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February 2011, Vol. 49, No. 2

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Passive Optical Networks

l ria to Tu eo c id So d V 9 om n ge C dba Pa ee oa e Fr Br Se

Special Supplement

MAGAZINE

•Next-Generation Mobile Networks •Synchronization over Next Generation Packet Networks

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RF Signal Generators There’s always room for improvement The Agilent N5181A-503 is an excellent 100 kHz to 3 GHz signal generator.

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Director of Magazines Andrzej Jajszczyk, AGH U. of Sci. & Tech. (Poland)

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IEEE

Editor-in-Chief Steve Gorshe, PMC-Sierra, Inc. (USA) Associate Editor-in-Chief Sean Moore, Centripetal Networks (USA) Senior Technical Editors Tom Chen, Swansea University (UK) Nim Cheung, ASTRI (China) Nelson Fonseca, State Univ. of Campinas (Brazil) Torleiv Maseng, Norwegian Def. Res. Est. (Norway) Peter T. S. Yum, The Chinese U. Hong Kong (China) Technical Editors Sonia Aissa, Univ. of Quebec (Canada) Mohammed Atiquzzaman, U. of Oklahoma (USA) Paolo Bellavista, DEIS (Italy) Tee-Hiang Cheng, Nanyang Tech. U. (Rep. Singapore) Jacek Chrostowski, Scheelite Techn. LLC (USA) Sudhir S. Dixit, Nokia Siemens Networks (USA) Stefano Galli, Panasonic R&D Co. of America (USA) Joan Garcia-Haro, Poly. U. of Cartagena (Spain) Vimal K. Khanna, mCalibre Technologies (India) Janusz Konrad, Boston University (USA) Abbas Jamalipour, U. of Sydney (Australia) Deep Medhi, Univ. of Missouri-Kansas City (USA) Nader F. Mir, San Jose State Univ. (USA) Amitabh Mishra, Johns Hopkins University (USA) Sedat Ölçer, IBM (Switzerland) Glenn Parsons, Ericsson Canada (Canada) Harry Rudin, IBM Zurich Res.Lab. (Switzerland) Hady Salloum, Stevens Institute of Tech. (USA) Antonio Sánchez Esguevillas, Telefonica (Spain) Heinrich J. Stüttgen, NEC Europe Ltd. (Germany) Dan Keun Sung, Korea Adv. Inst. Sci. & Tech. (Korea) Danny Tsang, Hong Kong U. of Sci. & Tech. (Japan) Series Editors Ad Hoc and Sensor Networks Edoardo Biagioni, U. of Hawaii, Manoa (USA) Silvia Giordano, Univ. of App. Sci. (Switzerland) Automotive Networking and Applications Wai Chen, Telcordia Technologies, Inc (USA) Luca Delgrossi, Mercedes-Benz R&D N.A. (USA) Timo Kosch, BMW Group (Germany) Tadao Saito, University of Tokyo (Japan) Consumer Communicatons and Networking Madjid Merabti, Liverpool John Moores U. (UK) Mario Kolberg, University of Sterling (UK) Stan Moyer, Telcordia (USA) Design & Implementation Sean Moore, Avaya (USA) Salvatore Loreto, Ericsson Research (Finland) Integrated Circuits for Communications Charles Chien (USA) Zhiwei Xu, SST Communication Inc. (USA) Stephen Molloy, Qualcomm (USA) Network and Service Management Series George Pavlou, U. of Surrey (UK) Aiko Pras, U. of Twente (The Netherlands) Networking Testing Series Yingdar Lin, National Chiao Tung University (Taiwan) Erica Johnson, University of New Hampshire (USA) Tom McBeath, Spirent Communications Inc. (USA) Eduardo Joo, Empirix Inc. (USA) Topics in Optical Communications Hideo Kuwahara, Fujitsu Laboratories, Ltd. (Japan) Osman Gebizlioglu, Telcordia Technologies (USA) John Spencer, Optelian (USA) Vijay Jain, Verizon (USA) Topics in Radio Communications Joseph B. Evans, U. of Kansas (USA) Zoran Zvonar, MediaTek (USA) Standards Yoichi Maeda, NTT Adv. Tech. Corp. (Japan) Mostafa Hashem Sherif, AT&T (USA) Columns Book Reviews Andrzej Jajszczyk, AGH U. of Sci. & Tech. (Poland) History of Communications Mischa Schwartz, Columbia U. (USA) Regulatory and Policy Issues J. Scott Marcus, WIK (Germany) Jon M. Peha, Carnegie Mellon U. (USA) Technology Leaders' Forum Steve Weinstein (USA) Very Large Projects Ken Young, Telcordia Technologies (USA) Publications Staff Joseph Milizzo, Assistant Publisher Eric Levine, Associate Publisher Susan Lange, Online Production Manager Jennifer Porcello, Publications Specialist Catherine Kemelmacher, Associate Editor

®

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MAGAZINE February 2011, Vol. 49, No. 2

www.comsoc.org/~ci SPECIAL SUPPLEMENT ADVANCES IN PASSIVE OPTICAL NETWORKS GUEST EDITORS: MAHMOUD DANESHMAND, CHONGGANG WANG, AND WEI WEI

S12 GUEST EDITORIAL S16 OPPORTUNITIES FOR NEXT-GENERATION OPTICAL ACCESS Next-generation optical access technologies and architectures are evaluated based on operators’ requirements. The study presented in this article compares different FTTH access network architectures. DIRK BREUER, FRANK GEILHARDT, RALF HÜLSERMANN, MARIO KIND, CHRISTOPH LANGE, THOMAS MONATH, AND ERIK WEIS

S25 COST AND ENERGY CONSUMPTION ANALYSIS OF ADVANCED WDM-PONS The authors compare several WDM-PON concepts, including hybrid WDM-PON with integrated per-wavelength multiple access, with regard to these parameters. They also show the impact and importance of generic next-generation bandwidth and reach requirements. KLAUS GROBE, MARKUS ROPPELT, ACHIM AUTENRIETH, JÖRG-PETER ELBERS, AND MICHAEL EISELT

S33 TOWARD ENERGY-EFFICIENT 1G-EPON AND 10G-EPON WITH SLEEP-AWARE MAC CONTROL AND SCHEDULING The authors briefly discuss the key features of 10G-EPON. Then, from the perspective of MAC-layer control and scheduling, they discuss challenges and possible solutions to put optical network units into low-power mode for energy saving. JINGJING ZHANG AND NIRWAN ANSARI

S39 MULTIRATE AND MULTI-QUALITY-OF-SERVICE PASSIVE OPTICAL NETWORK BASED ON

HYBRID WDM/OCDM SYSTEM

The authors present a new scheme to support multirate and multi-quality-of-service transmission in passive optical networks based on a hybrid wavelength-division multiplexing/optical code-division multiplexing scheme. The idea is to use multilength variable-weight optical orthogonal codes as signature sequences of a hybrid WDM/OCDM system. HAMZEH BEYRANVAND AND JAWAD A. SALEHI

S45

PASSIVE OPTICAL NETWORK MONITORING: CHALLENGES AND REQUIREMENTS The authors address the required features of PON monitoring techniques and review the major candidate technologies. They highlight some of the limitations of standard and adapted OTDR techniques as well as non-OTDR schemes. MOHAMMAD M. RAD, KERIM FOULI, HABIB A. FATHALLAH, LESLIE A. RUSCH, AND MARTIN MAIER

IMT-ADVANCED AND NEXT-GENERATION MOBILE NETWORKS GUEST EDITORS: WERNER MOHR, JOSE F. MONSERRAT, AFIF OSSEIRAN, AND MARC WERNER

82 84

GUEST EDITORIAL

92

ASSESSING 3GPP LTE-ADVANCED AS IMT-ADVANCED TECHNOLOGY: THE WINNER+ EVALUATION GROUP APPROACH

EVOLUTION OF LTE TOWARD IMT-ADVANCED The authors provide a high-level overview of LTE Release 10, sometimes referred to as LTE-Advanced. First, a brief overview of the first release of LTE and some of its technology components is given, followed by a discussion on the IMT-Advanced requirements. The technology enhancements introduced to LTE in Release 10, carrier aggregation, improved multi-antenna support, relaying, and improved support for heterogeneous deployments, are described. STEFAN PARKVALL, ANDERS FURUSKÄR, AND ERIK DAHLMAN

The authors describe the WINNER+ approach to performance evaluation of the 3GPP LTE-Advanced proposal as an IMT-Advanced technology candidate. The official registered WINNER+ Independent Evaluation Group evaluated this proposal against ITU-R requirements. The authors provide an overview of the ITU-R evaluation process, criteria, and scenarios, and focus on the working method of the evaluation group. KRYSTIAN SAFJAN, VALERIA D’AMICO, DANIEL BÜLTMANN, DAVID MARTIN-SACRISTAN, AHMED SAADANI, AND HENDRIK SCHÖNEICH

IEEE Communications Magazine • February 2011

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See into the future of wireless technology with tools that stay ahead of it. Agilent 89600B vector signal analysis (VSA) software enables more simultaneous views of virtually every aspect of complex wireless signals. The result is an unprecedented ability to understand signal problem root causes today and in the future. That’s clarity. That’s Agilent. NEW! 89600B VSA Software Up to 20 traces, 20 markers each > 70 signal standards and modulations Advanced time, frequency and modulation tools > 30 supported measurement platforms

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Communications IEEE

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2011 Communications Society Elected Officers

102

Byeong Gi Lee, President Vijay Bhargava, President-Elect Mark Karol, VP–Technical Activities Khaled B. Letaief, VP–Conferences Sergio Benedetto, VP–Member Relations Leonard Cimini, VP–Publications Members-at-Large Class of 2011 Robert Fish, Joseph Evans Nelson Fonseca, Michele Zorzi Class of 2012 Stefano Bregni, V. Chan Iwao Sasase, Sarah K. Wilson Class of 2013 Gerhard Fettweis, Stefano Galli Robert Shapiro, Moe Win 2011 IEEE Officers Moshe Kam, President Gordon W. Day, President-Elect Roger D. Pollard, Secretary Harold L. Flescher, Treasurer Pedro A. Ray, Past-President E. James Prendergast, Executive Director Nim Cheung, Director, Division III IEEE COMMUNICATIONS MAGAZINE (ISSN 01636804) is published monthly by The Institute of Electrical and Electronics Engineers, Inc. Headquarters address: IEEE, 3 Park Avenue, 17th Floor, New York, NY 10016-5997, USA; tel: +1-212705-8900; http://www.comsoc.org/ci. Responsibility for the contents rests upon authors of signed articles and not the IEEE or its members. Unless otherwise specified, the IEEE neither endorses nor sanctions any positions or actions espoused in IEEE Communications Magazine.

122

A 25 GB/S(/KM2) URBAN WIRELESS NETWORK BEYOND IMT-ADVANCED

AND

REPRINT

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Send address changes to IEEE Communications Magazine, IEEE, 445 Hoes Lane, Piscataway, NJ 08855-1331. GST Registration No. 125634188. Printed in USA. Periodicals postage paid at New York, NY and at additional mailing offices. Canadian Post International Publications Mail (Canadian Distribution) Sales Agreement No. 40030962. Return undeliverable Canadian addresses to: Frontier, PO Box 1051, 1031 Helena Street, Fort Eire, ON L2A 6C7

SUBSCRIPTIONS, orders, address changes — IEEE Service Center, 445 Hoes Lane, Piscataway, NJ 08855-1331, USA; tel: +1-732-981-0060; e-mail: [email protected]. ____________

The authors present a survey on the technical challenges of future radio access networks beyond LTE-Advanced, which could offer very high average area throughput to support a huge demand for data traffic and high user density with energyefficient operation. They highlight various potential enabling technologies and architectures to support the aggressive goal of average area throughput 25 Gb/s/km2 in beyond IMT-Advanced systems. SHENG LIU, JIANJUN WU, CHUNG HA KOH, AND VINCENT K. N. LAU

GUEST EDITORS: STEFANO BREGNI AND RAVI SUBRAHMANYAN

130 132

GUEST EDITORIAL

140

SYNCHRONIZATION OF AUDIO/VIDEO BRIDGING NETWORKS USING IEEE 802.1AS

148

NGN PACKET NETWORK SYNCHRONIZATION MEASUREMENT AND ANALYSIS

156

PERFORMANCE ASPECTS OF TIMING IN NEXT-GENERATION NETWORKS

164

USING IEEE 1588 AND BOUNDARY CLOCKS FOR CLOCK SYNCHRONIZATION IN TELECOM NETWORKS

ADVERTISING: Advertising is accepted at the discretion of the publisher. Address correspondence to: Advertising Manager, IEEE Communications Magazine, 3 Park Avenue, 17th Floor, New York, NY 10016. SUBMISSIONS: The magazine welcomes tutorial or survey articles that span the breadth of communications. Submissions will normally be approximately 4500 words, with few mathematical formulas, accompanied by up to six figures and/or tables, with up to 10 carefully selected references. Electronic submissions are preferred, and should be sumitted through Manuscript Central http://mc.manuscriptcentral.com/commag-ieee. Instructions can be found at the following: ______ http://dl.comsoc.org/livepubs/ci1/info/sub_guidelines.html. For further ____________________ information contact Sean Moore, Associate Editor-inChief ([email protected]). ___________ All submissions will be peer reviewed.

The evolution of LTE uplink transmission toward MIMO has recently been agreed in 3GPP, including the support of up to four-layer transmission using precoded spatial multiplexing as well as transmit diversity techniques. The authors provide an overview of these uplink MIMO schemes, along with their impact on reference signals and DL control signaling. CHESTER SUNGCHUNG PARK, Y.-P. ERIC WANG, GEORGE JÖNGREN, AND DAVID HAMMARWALL

SYNCHRONIZATION OVER ETHERNET AND IP IN NEXT-GENERATION NETWORKS

EDITORIAL CORRESPONDENCE: Address to: Editorin-Chief, Steve Gorshe, PMC-Sierra, Inc., 10565 S.W. Nimbus Avenue, Portland, OR 97223; tel: +(503) 4317440, e-mail: [email protected]. Abstracting is permitted with credit to the source. Libraries are permitted to photocopy beyond the limits of U.S. Copyright law for private use of patrons: those post-1977 articles that carry a code on the bottom of the first page provided the per copy fee indicated in the code is paid through the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923. For other copying, reprint, or republication permission, write to Director, Publishing Services, at IEEE Headquarters. All rights reserved. Copyright © 2011 by The Institute of Electrical and Electronics Engineers, Inc.

EVOLUTION OF THE STANDARDS FOR PACKET NETWORK SYNCHRONIZATION The authors summarize the work done by ITU-T Q13/15 over the last six years to standardize the transport of timing over packet networks. They provide a summary of the published documents in this area from ITU-T while providing some of the background that went into each document including the specification of synchronous Ethernet and IEEE 1588 telecom profiles. JEAN-LOUP FERRANT AND STEFANO RUFFINI The Audio/Video Bridging project in the IEEE 802.1 working group is focused on the transport of time-sensitive traffic over IEEE 802 bridged networks. Current bridged networks do not have mechanisms that enable meeting these requirements under general traffic conditions. IEEE 802.1AS is the AVB standard that will specify requirements to allow for transport of precise timing and synchronization in AVB networks. GEOFFREY M. GARNER AND HYUNSURK (ERIC) RYU As the transport of data across the network relies increasingly on Ethernet/IP methods and less on the TDM infrastructure, the need for packet methods of synchronization transport arises. Evaluation of these new packet methods of frequency and time transport requires new approaches to timing measurement and analysis. LEE COSART Circuit-switched networks based on time-division multiplexing require synchronization to deliver information, whereas packet-switched networks can deliver information in an asynchronous environment. However, all real-time services require that synchronization and timing information be delivered over the network. Performance of timing distribution is quantified using particular metrics and adherence to requirements determined by using masks. KISHAN SHENOI

The authors describe the use of IEEE 1588 and boundary clocks for clock distribution in telecom networks. The technology is primarily used to serve the radio interface synchronization requirements of mobile systems such as WiMAX and LTE, and to reduce the deployment and dependence of GPS systems in base stations. MICHEL OUELLETTE, KUIWEN JI, SONG LIU, AND HAN LI President’s Page Letters to the Editor Certification Corner New Products

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Coordinated multipoint or cooperative MIMO is one of the promising concepts to improve cell edge user data rate and spectral efficiency beyond what is possible with MIMO-OFDM in the first versions of LTE or WiMAX. Interference can be exploited or mitigated by cooperation between sectors or different sites. Significant gains can be shown for both the uplink and downlink. RALF IRMER, HEINZ DROSTE, PATRICK MARSCH, MICHAEL GRIEGER, GERHARD FETTWEIS, STEFAN BRUECK, HANS-PETER MAYER, LARS THIELE, AND VOLKER JUNGNICKEL

EVOLUTION OF UPLINK MIMO FOR LTE-ADVANCED

tion. $16 per year digital subscription. Non-member print subscription: $400. Single copy price is $25.

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COORDINATED MULTIPOINT: CONCEPTS, PERFORMANCE, AND FIELD TRIAL RESULTS

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Conference Calendar Product Spotlights Global Communications Newsletter Advertisers’ Index

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COMSOC MARKETING: VALUED OFFERINGS FOR VALUED CUSTOMERS

M

and challenges that must be addressed in arketing, in general, is a term that order to best serve ComSoc customers. I we often use, but are not sure of the share this issue with Stan Moyer, ComSoc exact definition. For the purposes of this artiDirector of Marketing and Industry Relacle, we cite the definition provided by the tions, and John Pape, (staff) Director of MarAmerican Marketing Association.1 keting and Creative Services. Marketing is the activity, set of institutions, Stan Moyer is an executive director and and processes for creating, communicating, strategic research program manager in the delivering, and exchanging offerings that have Applied Research area of Telcordia Techvalue for customers, clients, partners, and nologies, where he has worked since 1990. society at large. Currently, he is leading a business developKey to this definition is the concept that ment effort for end-user information privacy “offerings” must have value for the customer. protection for mobile services. In the past he Therefore, determining what products and led research and business development activiservices customers find of value is a crucial ties related to digital content services and aspect of marketing. Our members are “cusBYEONG GI LEE home networking. He has also worked on tomers,” with the Society’s marketing efforts ATM switch hardware, broadband having primary focus on satisfying network architectures and prototheir needs while meeting the cols, middleware, Internet network broader goals of their Society. Since and application security, Internet any organization must operate withQoS, and voice over IP. He is curin the boundaries of its mission rently President of the OSGi and/or goals, we revisit the goals of Alliance. He served as a member of the IEEE Communications Society the IEEE Technical Activities (ComSoc) first, which are two-fold: Board Finance Committee. Within •Scholarly — scientific and ComSoc, he is currently serving as directed toward the advancement of Director-Marketing and Industry the theory, practice, and application Relations, a member of the Comof communications engineering and Soc Standards Board, Vice-Chair of related arts and sciences. the IEEE CCNC steering commit•Professional — promoting high tee, and co-Chair of the Ad hoc professional standards, developSTAN MOYER JOHN PAPE Industry Promotion Committee. ment of competency and the Stan has a ME degree in Electrical advancement of the standings of Engineering from Stevens Institute of Technology and an members of the professions. MBA degree in Technology Management from the University These goals are implemented through a diverse set of of Phoenix. activities by members and the business actions managed by John Pape has served as the (staff) Director of Marketing volunteer leaders and paid staff. Our main business includes and Creative Services since 1997. His responsibilities include publishing journals and magazines, holding meetings and conplanning and implementing the society’s marketing activities ferences, offering education and training, and selling adverfor membership, publications, continuing education, and contisements. Our business is to serve ComSoc’s customers, ferences. During his tenure, products have migrated from including members, and to achieve the goals of the Society. print to electronic media, and marketing tactics have evolved Next, we need to understand the background of ComSoc’s from direct mail and manual processing to complicated e-mail customers, which include members, publication subscribers, campaigns and social media outreach. Recently, he has led conference attendees, and recipients of other ComSoc serComSoc’s efforts to provide members with a digital option for vices. Most current members have advanced educations: postIEEE Communications Magazine and to create and execute graduate degrees in EE, physics, mathematics, computer the plan to offer a virtual course in wireless communications sciences, business, or related fields. engineering. From 1989 to 1997, he managed the Publications Serving ComSoc’s “customers” is the mission of ComSoc’s Marketing Department of the American Society of Civil EngiMarketing and Creative Services Department, which promotes neers. He has managed marketing activities for more than 30 all ComSoc products and provides creative services to Comyears with international publishers including S. Karger PubSoc officers, volunteers, and all other departments of Comlishers, Methuen, and Springer-Verlag. Soc. The department completes over 300 marketing projects per year in order to refine and renew ComSoc’s offerings. COMPETITORS AND ADDRESSABLE MARKET ComSoc offerings can be grouped into four major areas: membership, publications, conferences, and education & ComSoc, just like most businesses, has competitors for its training. products and services. ComSoc competes for time, prestige, In this article we will describe the marketing of ComSoc in money, authors, attendees, readers, volunteers, subscribers, terms of ComSoc offerings, marketing process, and the issues and resources with other organizations, events, publishers, and information sources in the communications field. Some might 1 American Marketing Association website, _______________ consider communications websites or self-organized social http://www.marketingpowmedia as directly competitive as they can provide alternative er.com/aboutama/pages/definitionofmarketing.aspx

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Telecommunications Management and technical consulting Scientific R&D services

US employment trends (1000s)

1400

1200

1000

800

600

400 1/99

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1/01

1/02

1/03

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1/05

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1/07

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FIGURE 1. U.S. employment trends. resources for members and potential members. Some known competitors, in that context, include trade or corporate-centric organizations such as the ITU, GSMA, IET, ACM, TIA, ATIS, CTIA, AFCEA, OSA, ISOC, and other national organizations. Publishers such as John Wiley and Sons, SpringerVerlag, CMP, Cambridge University Press, and Elsevier provide alternative global publications (books, journals, magazines) as information sources and legitimate venues for scholarly authors and practical technical publishing. Certain forums and/or special interest groups (SIGs) deal with rapid technological developments, such as the WiMax Forums, Telecommunications Management Forum, NGN, IMS, and the Femto Forum. Trade shows and technical conferences (sponsored by corporate entities such as the Yankee Group or non-profits such as PCIA) on communications topics can be found throughout the year at locations around the globe. Within the IEEE, other societies such as Antennas and Propagation, Signal Processing, Vehicular Technology, Information Theory, Computer, Photonics, Consumer Electronics, and Microwave Theory and Techniques all have some technical overlap with ComSoc. However, ComSoc does not have a broad-based direct global competitor serving individuals within the global community in its technical scope. When marketing products and services, it helps to understand the addressable market – that is, the entire space for which our products and services would be of interest. Defining the estimated universe of potential members or communications related subject matter experts can be a challenge. Based on published data, there have been about 800,000 EE BS degrees granted in the US in the past 40 years. Less than half of them attained a Master’s degree or Ph.D. level degree. Historically about 14% enter communications-centric employment, resulting in about 110,000 individuals with an undergraduate degree and about 50,000 individuals holding an EE Master’s degree or higher in the US. With 20,000 members in the US, ComSoc member demographics imply that ComSoc has captured about 25% of the potential US market holding Master’s degrees or higher. Of those earning a Bachelor’s Degree, data would suggest that ComSoc has captured about 10% of the potential US universe. The potential member universe could include other disciplines such as physics, mathematics, computer science, and business management, but all EE graduates do not pursues careers in EE fields. Data sources for the international higher education area and employment markets are unreliable and inconsistent; it is not possible to estimate realistically the global member universe, although someone may estimate the size to be double the US.

The US Department of Labor maintains employment data for the telecom industry for all employees (including nondegreed employees). Employment in the traditional telecommunications industry has declined by 35% since reaching highs of more than 1.4 million in 2000; there have been other areas of employment growth. While telecom employers have been shedding traditional full-time employees, technical consulting and scientific research employment have increased by 50% in the last decade. As a result, the US membership market is not as apparent or easily accessible as it once was. Communications specialists can be found in a much broader array of companies and working scenarios. Figure 1, drawn based on the US Bureau of Labor statistics charts, represents this shift graphically.

MEMBERSHIP One of the primary “products” that ComSoc provides to “customers” is membership in the society. As a society of the IEEE, ComSoc membership is offered for a fee in addition to IEEE membership dues. ComSoc sets the price and defines the benefits of society membership. The prime justifications for membership are to maintain technical competence, receive desired services at discounted rates, and network with colleagues. Each member receives monthly issues of IEEE Communications Magazine, the leading technical periodical devoted to communications technologies on an advanced level. ComSoc membership dues are $25 in 2011, with digital delivery of IEEE Communications Magazine; in 1999 ComSoc membership dues were $23 with print delivery of IEEE Communications Magazine. From the end of February to the end of September each year, dues for new members are half the regular price. ComSoc membership was about 8,800 when the Society was founded in 1963 with the establishment of IEEE. Membership has increased rapidly over the past 15 years, which was influenced by the half-year free membership campaign started in 1998 and the technology bubble of the late 1990’s. However, it began to decline from the early 2000’s due to the rapid decline of traditional telecommunications employment and full implementation of IEEE Xplore, which resulted in online IEEE (and ComSoc) content availability. The membership decline stopped at the 40,000+ level in the late 2000’s and maintained that level until it began to increase in 2010 to about 48,000. The majority of ComSoc members reside outside the US, whereas the majority of IEEE members reside in the US. This is the result of several phenomena. The communications industry diffused globally and became successful in many Asian and European countries. IEEE Xplore sales penetration in the US market has resulted in many potential US members satisfying their need for technical publications without joining ComSoc. In the late 1990’s, our surveys indicated that more than 62% of members were industry-employed; in 2008 that number decreased to 45%. This indicates that any membership growth in the future is most likely to come with the support of industry, consulting, or government areas. Each year ComSoc recruits about 11,000 new members. The majority of these new members result from offering to new IEEE members a free ComSoc membership for the first year. Some new members join during the annual IEEE renewal process. To recruit new members, marketing executes various print, online, and e-mail direct response campaigns; trade show exhibits; free book premiums; conference registration offers; and monthly new IEEE member e-campaigns. In addition, membership recruiting is supported by extensive web page updating; distributing promotion material to Sister Societies;

IEEE Communications Magazine • February 2011

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% of CommMag Readers that Read

EE Times

23.50%

Telecommunications

20.60%

EDN

15.90%

Electronic Design

15.10%

Wireless Design & Development

13.60%

Microwave & RF

13.20%

Network World

13.10%

Microwave Journal

12.60%

Lightwave

8.90%

Business Communications Review

7.00%

Test & Measurement World

6.50%

Internet Telephony

5.60%

Photonics Spectra

4.90%

Telephony/ Connected Planet

4.10%

Urgent Communications

2.70%

TABLE 1. Percentage of CommMag readers that read other magazines. local Chapter support with promotion material, sample copies, posters and special offers; cover wraps; free offers of a brief communications history book highlighting Society notables; an up-to-date Society PowerPoint presentation for group presentations; back-office coordination/support for data and other membership development activities such as Chapter Chair Congresses, Distinguished Lecturer Tours, and volunteer visits; Best of the Best and other book/DVD/product special offers; and special opportunistic efforts. In recent years, the Industry Now program has been established to offer bulk or multiple memberships to companies in emerging economies that are not acquainted with the advantages of ComSoc association. Retaining members is a constant process of providing reminders and opportunities to members that illustrate the value of membership. The annual ComSoc Community Directory and letter from the President are sent to each new ComSoc member on a biweekly basis. Members are surveyed for satisfaction and needs. Articles and columns dealing with member issues appear every month in IEEE Communications Magazine, as do advertisements specifically aimed at members. Monthly issues of e-News spotlight the President’s monthly message and present member-only special offers, including conference registrations, the Book of the Month, free tutorials, technically sponsored Webinars, new product offers, and other useful information such as the Top Ten list of ComSoc papers appearing in IEEE Xplore, and content announcements for optional publications. Support for volunteer committees, Chapters, Distinguished Lecturer Tours, premiums, and other programs also contribute to retention efforts.

PUBLICATIONS ComSoc publishes magazines, journals/transactions, proceedings, DVDs, books (with IEEE’s publisher John Wiley and independently) and newsletters. There are several methods to measure the popularity and effectiveness of periodical publications, e.g., subscription data, electronic PDF downloads, submissions, the ISI Journal Citation report, and reader/member surveys. Most periodicals are available in print or electronic format.

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There are three general categories for the subscription market: subscription agents; libraries; and individuals. ComSoc relies heavily on IEEE Sales and Marketing for sales to libraries and to subscription agents; all electronic package sales, including consortia licensing sales, are handled by the IEEE. The IEEE offers several packages of periodicals. The All Societies Periodical Package (ASPP), Enterprise, the IEEE Electronic Library (IEL), and the new IEEE Communications Library are among the offerings that include ComSoc periodicals and conference proceedings. IEEE participates in library conferences such as the ALA and SLA annual trade shows. All ComSoc periodicals are included in the annual Society brochure, on Society Membership applications, online web and PDF formats, and in the ComSoc Community directory. IEEE Communications Magazine (CommMag) is the most important Society publication, which all members receive monthly. The editorial data reflects hot topics of interest to members and is written in a style to be accessible to all members, with academic and corporate interests alike. CommMag is a hybrid publication, containing editorial material that can be described as scholarly with sufficient industry attraction to generate $1 million plus in advertising sales each year. No other IEEE society magazine can claim the distinction of most non-member subscriptions, most 2009 magazine Xplore views, high ISI Journal Citation Report impact factor (rated #5 in telecommunications in 2009), and $1+ million generated in advertising revenue. CommMag is the most significant scholarly/industry publication in the specialty of communications. To emphasize the uniqueness of ComSoc members, a survey of readers found that no competitive trade publication was read by more than 25% of CommMag readers (see Table 1). IEEE Wireless Communications Magazine and IEEE Network Magazine complement IEEE Communications Magazine and focus on two strong areas of communications technology. These are optional bi-monthly publications with technical cosponsorship with the Computer Society. Both are similar to CommMag in layout and offer a broader readership concept. Core ComSoc archival journals/transactions including IEEE Transactions on Communications, IEEE Journal on Selected Areas in Communications, IEEE Communications Letters, IEEE Communications Surveys and Tutorials (e-only), and IEEE Transactions on Network and Service Management (eonly) reflect the scope of the scholarly activity. And financially co-sponsored journals such as IEEE Transactions on Wireless Communications, IEEE/ACM Transactions on Networking, IEEE/OSA Journal of Lightwave Technology, IEEE/OSA Journal of Optical Communications and Networking, and IEEE Transactions on Mobile Computing demonstrate relationships with other related specialties.

CONFERENCES All conferences sponsored and co-sponsored by ComSoc are marketed and promoted by mixed media through different channels. The degree of marketing effort increases as the level of financial ownership and budget increases. For a specific event, a separate marketing plan or strategy is created. There are some common areas. Most of these events include conference proceedings with papers also appearing online in IEEE Xplore. This results in authors/presenters wanting to submit papers and contribute to the conferences and ComSoc revenue. Conferences generate more gross revenue than any other product in the portfolio, and conferences command more marketing resources than any other products in the ComSoc portfolio. Conferences have different levels of financial co-sponsor(Continued on page 10)

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_____________________________________________________

This tutorial addresses the key challenges related to the delivery of high quality next-generation video. It describes important techniques that can be exploited to enhance video transmission over a broad range of networks: bandwidth-constrained managed private networks, error-prone over-the-air broadcast networks, as well as unmanaged online networks that often lose packets due to network congestion. Key topics covered include H.264/VC-1/VP8 video coding, bandwidth management and conservation, video quality improvement via error concealment, adaptive streaming, 3D/multiview video technologies, and advanced user-TV interface. FREE ACCESS SPONSORED BY For other sponsor opportunities, please contact Eric Levine, Associate Publisher Phone: 212-705-8920, E-mail: ______________ [email protected]

Communications IEEE

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THE PRESIDENT’S PAGE (Continued from page 8) ship that range from fully financially sponsored by ComSoc (e.g., ICC, GLOBECOM, CCNC), financially co-sponsored by ComSoc (e.g., OFC/NFOEC, MILCOM), and conferences with no financial sponsorship (IEEE Sarnoff 2009, WTS 2009, IEEE Policy 2009). Those conferences are typically technically co-sponsored by ComSoc. Depending on budgets, most fully-owned ComSoc conference marketing includes web site development, Call-forPapers (CFP) assistance, advance and final program design and production, online and media advertising, flyers, and a series of e-mail efforts. Recently, there have been additional activities such as recording live sessions and other program events. Under the ComSoc Webcasts brand, access to these events can be purchased for live participation or recorded listening. Often, a keynote speech can be enjoyed free of charge. At some recent flagship events, there have been increased visibility activities with press releases and local, national, and global media coverage. Some ComSoc volunteer leaders have made trips to local high schools and colleges to explain the benefits of careers in the communications sciences. At a recent MILCOM, high school science students visited the exhibit floor to sample the experience and view the scope of the industry. Social media – e.g., blogs, Facebook, Linkedin, Twitter – are now playing a larger role in conference marketing. ComSoc has more than 35 social media sites dedicated to conferences! Social media also provides new ways for registrants to participate. Marketing efforts related to conferences not only help to promote the conference, but also utilize the conference to market other ComSoc products and services. Conferences serve as a great forum for the ComSoc marketing staff and volunteers to meet ComSoc members and conference attendees to get feedback and input on what they do and do not like about ComSoc, the conference, and other products and services.

EDUCATION AND TRAINING

IN CLOSING

Continuing education and/or educational products/product development are important but least developed areas within ComSoc. In reality, everything ComSoc produces falls under the subject of education, and most member surveys indicate support for additional educational opportunities. In response, we plan to invest intensive efforts to fully develop the education and training areas in accordance with the progress of the mobile converged communications era. Conference Tutorials are developed with ComSoc events, but they are developed under the banner of the event itself, so marketing for these tutorials falls under the domain of the individual event. Tutorials Now represent an online portfolio of individual half-day or full-day tutorials that had been given at ComSoc events. The total number of titles accumulated so far is 84, but it grows every year. Selected presenters record voice over slide presentations after the event and forward the completed files to ComSoc for quality control testing and uploading. Presenters receive an honorarium and/or royalties for accepted tutorials. Recently these tutorials have been indexed for access through the ComSoc Digital Library. Some Tutorial Now modules are offered as potential sponsorship to companies. These can be offered to ComSoc members free of charge for a limited time when a sponsor has been secured. Courses/sessions can be developed for non-ComSoc conferences and trade shows. In 2009 and 2010, a course on

With a membership of more than 48,000 global individuals, ComSoc is the second largest IEEE society and has strong volunteer commitments, a dedicated staff, expert operational support, and a global reputation of excellence. ComSoc excels at producing technical publications, organizing technical conferences, as well as fostering educational programs. ComSoc has a potential to grow much more in the future while undergoing transformation toward the converged communications era. ComSoc’s marketing has adapted to many changes in the past decade, thus enabling ComSoc to reach its current status. Anticipating future opportunities, the ComSoc volunteer/staff partnership for marketing will support increased industry patronage, new partnerships with organizations and companies that can help enhance ComSoc’s position as the “go-to” resource for the communications industry. Further, it will help promote new publications and conferences in emerging communications areas, develop new services geared to industry, attract non-US members, expand digital delivery of information and virtual meetings, explore social media opportunities, and prepare for the unexpected. ComSoc’s marketing will keep playing a pivotal role while ComSoc navigates through the newly emerging converged communications era, creating new offerings that have value for the ComSoc’s customers and thereby making ComSoc a valuable home for all the communications communities and professionals of the world.

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Wireless Communications (specifically the areas covered by the WCET certification program) was held at 4G World in Chicago. A five-day virtual intensive course on Wireless Communications was held in September 2010. This first offering was very successful, with 75 registrants from 15 countries. Each day’s sessions were held over the Internet; participants never had to leave their computers. For 2011, the five-day virtual intensive course on wireless communications is scheduled for multiple offering times. Eventually this event could be settled as a quarterly or bimonthly course, demand permitting. ComSoc’s WCET (Wireless Communication Engineering Technologies) Certification Program was officially launched in early 2008. It was developed by ComSoc and an international collection of industry experts to address the worldwide wireless industry’s growing need for professionals with real-world problem-solving skills. Industry consensus, obtained through an industry survey with more than 1,300 individual responses representing more than 65 countries from around the world, was that a wireless certification program is necessary. The purpose of the WCET is to certify individuals in wireless communications. Two testing windows are offered each year, during which individuals can sit for the exam. There are more than 500 testing sites located in 75 countries around the world. The exam is administered at a Computer Based Testing facility and consists of 150 multiple-choice questions encompassing seven major wireless areas: RF engineering; propagation and antennas; access technologies; network and service architecture; network management and security; facilities infrastructure; agreements, standards, policies, and regulations; and fundamental knowledge. The WCET program has evolved for the past two years while passing through a learning curve. Marketing strategy for the WCET exam originally started with the objective to generate direct individual applications, but the focus was changed from the individual to the company and from the exam to training. The five-day virtual intensive course thus developed has proved popular with industry and provides a natural sequence for those wishing to successfully navigate the WCET exam.

IEEE Communications Magazine • February 2011

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Mobile WiMAX A Systems Approach to Understanding IEEE 802.16m Radio Access Technology By Sassan Ahmadi ISBN: 978-0-12-374964-2 List Price: $99.00 I £60.99 | €71.95

NEW Just Published title Hot Technology

DESCRIPTION: Presenting the new IEEE 802.16m standard, this is the first book to take a systematic, topdown approach to describing Mobile WiMAX and its next generation, giving detailed algorithmic descriptions together with explanations of the principles behind the operation of individual air-interface protocols and network components.

FEATURES: • A systematic and detailed, top-down approach to the design of 4G cellular systems based on IEEE 802.16m and 3GPP LTE/LTE-Advanced technologies • A systematic approach to understanding IEEE 802.16m radio access network and mobile WiMAX network architecture and protocols • The first comprehensive technical reference on the design, development and performance evaluation of IMT-Advanced systems, including the theoretical background and design principles as well as implementation considerations ABOUT THE AUTHOR: The author, chief architect and technical lead of the IEEE 802.16m project at Intel Corporation, initiated and masterminded the development of the IEEE 802.16m standard and has been one of the leading technical drivers in its standardization process in IEEE. The author was also a leading technical contributor to the definition and development of requirements and evaluation methodology for the IMT-Advanced systems in ITU-R. Reflecting the author’s 20+ years expertise and experience, the book provides an in-depth, systematic and structured technical reference for professional engineers, researchers, and graduate students working in cellular communication systems, radio air-interface technologies, cellular communications protocols, advanced radio access technologies for 4G systems, and broadband cellular standards.

Available on elsevierdirect.com, Amazon and where ever fine books are sold. SAVE 20% + FREE SHIPPING when ordering on www.elsevierdirect.com. Enter promotional code wimax20 at checkout All prices and publication dates subject to change without notice. ©2010 by Elsevier. All Rights Reserved

Communications IEEE

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LETTERS TO THE EDITOR EDITED BY MISCHA SCHWARTZ Comments on “An Early History of the Internet” by Leonard Kleinrock Greg Adamson, Melbourne

To the Editor, I read your “History of Communications” pages with interest, and particularly the August 2010 article by Leonard Kleinrock. This article creates a challenge for the reader: how to weigh an account of historical events by a major participant in those events. I have separately seen the problem described as “military history written by generals.” You would be aware that Donald Davies in part covered the same ground in an article published in 2001 (The Computer Journal, vol. 44, no. 3, pp. 152–62). I found Davies’ account very moving: a renowned researcher in his dying months establishing his view of a contested period of discovery (and not to assert his own claim). After reviewing the work of Kleinrock and Paul Baran, he summed up his finding in the following way: “My contention is that the work of Kleinrock before and up to 1964 gives him no claim to have originated packet switching, the honour for which must go to Paul Baran. The passage in his book on time-sharing queue discipline, if pursued to a conclusion, might have led him to packet switching, but it did not.” I appreciate that Leonard Kleinrock would not agree with this perspective, yet I feel his article is too oblique. I would be very interested in seeing a

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more specific response to the points that Davies made. Perhaps you should have an occasional column titled “Debates in the History of Communications.” Response to Greg Adamson: by Leonard Kleinrock

In my August 2010 article, I state that the detail I afford to my perspective is based on personal experience and is not a claim to importance. I also call attention to many more histories of the Internet in need of study; Adamson calls this whole enterprise “military history written by generals” and has asked me to respond to claims he cites from the late Donald Davies in which my work on time-sharing is addressed. A major goal of packetization is to prevent long messages from hogging the channel and thereby causing shorter messages to wait inordinately. This was raised by Davies as a major concern since it provided the network operator the ability to control network delay rather than being at the mercy of the end user. In my 1962 dissertation I clearly considered the role of message priority classes and priority queueing disciplines in accomplishing this. Relating this to network delay, I devoted Chapter 5 to studying the “...manner in which message delay is affected when one introduces a priority structure (or queue discipline) into the set of messages....” I isolated the effect of queue discipline by looking at a single node, as “An understanding of the effects of a

priority discipline at the single-node level is necessary before one can make any intelligent statements about the multinode case.” Among the classes of discipline I studied were the preemptive disciplines where the transmission of a message can be interrupted and then continued later. I devoted an entire section to time-shared servicing of data traffic in which I broke messages into smaller, fixed size pieces. I also provided a mathematical analysis and showed that the deleterious effects of channel hogging were indeed avoided. It would take far more space to delineate the properties of packet switching, since it involves much more than just chopping messages into smaller fixed length segments (the issue addressed by Adamson to which I have herein responded). Briefly, it also involves network efficiency which I addressed with the broader issue of demand access; it involves robustness and reliability which comes about from distributed adaptive routing in a mesh network, which I also presented in my early work. In the August 2010 article, I explain how my work informed the technology of the ARPANET as well as its timing relative to that of Baran’s. Prior to the writing of Davies’ posthumous article, he contacted me about these topics, and I did respond accordingly. Dr. Adamson has raised these same issues, which I have already explained in my article.

IEEE Communications Magazine • February 2011

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Everything you need to get from 3G to LTE.

Broadest set of LTE design and test tools

Extensive LTE knowledge library

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Getting to market fast with LTE products requires up-to-date test tools and reliable insights. Count on the Agilent LTE Design and Test Portfolio for the broadest set of LTE design and test tools, plus a robust knowledge library of LTE app notes, CDs, expert help and more. In short, everything you need to interpret, clarify and test to the evolving LTE standard. With greater insight, and greater confidence. That’s Agilent.

Gain greater LTE insight and confidence www.agilent.com/find/LTEInsight © 2010 Agilent Technologies, Inc.

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u.s. 1-800-829-4444 canada: 1-877-894-4414

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CERTIFICATION CORNER THE VALUE OF VOLUNTEERS BY ROLF FRANTZ In many of the months this column has appeared, it has often included some words about the volunteers who have made WCET certification possible. It’s worth taking more time to describe the many roles that volunteers have played – and continue to play – because of the value they bring to the program. It started when the original Practice Analysis Task Force (PATF) convened in December 2006 to develop the Delineation (the description of wireless practice and underlying knowledge). The PATF included more than 15 industry experts from around the world who gave their time to get the program off to a strong start. Without their commitment, there would not be a WCET certification program. Several of these volunteers remain actively involved today, especially in championing the value of certification within the industry. The next volunteers were the participants in Focus Groups and the Independent Reviewers. Dozens of industry experts studied the Delineation and offered constructive feedback that helped make it

even more representative of wireless communications practice in a broad range of companies and countries. Again, some of those volunteers remained active in the WCET program for years, taking on specific roles and responsibilities, and their continued involvement has been valuable in guiding and growing the program. Special thanks go to the volunteers who have served on the Industry Advisory Board. They have given focused feedback on all aspects of the WCET program, ranging from promoting the program to industry to critiquing the WCET website. The fact that Board members represent companies in all segments of the wireless commu-

__________

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__________

nications industry, based in countries around the world, has helped maintain the vendor neutrality and trans-national nature of WCET certification. Other volunteers have served as question writers, question reviewers, and on the exam committee that has used the best questions to create exams covering the breadth of wireless communications. They have maintained the balance among the seven technical areas that was developed by the PATF and reinforced by industry feedback as to the relative importance of various tasks and knowledge in the workplace. Some of these volunteers recently joined with others to form a “mini-PATF” to review all the detailed feedback on the Delineation that we have received. They invested their time and effort to refresh and update the Delineation to reflect changes in the industry over the past few years. A Core Team of volunteers has provided steady leadership to the program throughout its history. They have led committees that looked at issues of policy, marketing, the Handbook, strategy, training, the WEBOK, recertification, and question writing and exam creation. A couple dozen volunteers have made a significant commitment to these leadership positions over the years. The Steering Committee is responsible for the long-term direction of the WCET program. More than a dozen volunteers have served on this committee, helping to identify strengths and weaknesses and also areas where ComSoc can build on the certification program. An example of the latter is the development of ComSoc training offerings, an area where there was a clear demand in the industry and a path within ComSoc to address the need. The title of this month’s column sums it up: the hundreds of volunteers who have played many different roles in the development, growth, guidance, and success of WCET certification have been our most valuable asset. We have expressed our thanks to each as they have relinquished a role or responsibility, but we owe one large THANK YOU to all of them. Attention WCP certificate holders in particular: volunteer opportunities abound! Please let us know how you would like to contribute to continuing to grow the WCET program to its full potential.

IEEE Communications Magazine • February 2011

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_____________________________________________________

SYSTEMS FOR WIRELESS COMMUNICATIONS (Or Orig ig gin inal a ly pre al r se ented nt at IEEE ICC CC C 200 06)

This MIMO tutorial begins by establishing the necessary basics: fundamentals, modeling of fading channels, transceiver architectures, diversity, space-time coding, and channel estimation. The tutorial then covers diversity vs. multiplexing trade-off, coherence vs. noncoherence, precoding and optimum signaling, and multiuser MIMO. Finally, MIMO applications in cellular systems and wireless LANs are covered, along with forthcoming applications. FREE ACCESS SPONSORED BY For other sponsor opportunities, please contact Eric Lev vine, in Associate Publisher Phone: 212-705-8920, E-mail: ______________ [email protected]

Communications IEEE

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NEW PRODUCTS CHIP FAMILY SUPPORTS THE ITU-T G.HN GLOBAL STANDARD Lantiq Lantiq has introduced a chip family supporting the ITU-T G.hn global standard for next generation wired home networks. Lantiq XWAY HNX devices provide manufacturers of consumer, computing and smart home electronics with the foundation for in-home networks that can be connected using any combination of phone, power and cable wiring. Endorsed by the 191 member countries of the ITU in June 2010, the G.hn standard defines technology to provide network connectivity across all common in-home wiring with data rates as high as 1 Gigabit per second (Gbps). As G.hn becomes an integral feature in residential gateways, consumer electronics devices, personal computers and Internet-connected smart home devices, service providers will be able to realize significantly reduced installation and operations costs as a result of plug-andplay network operation and greater device connectivity. Lantiq XWAY HNX chips can be used in standalone G.hn node applications or as part of multi-service platforms. The device is provided to customers with a software package that includes pre-integrated drivers for the broad range of Lantiq system-level silicon devices, including Gigabit speed gateway processors, 802.11n WLAN supporting carrier-grade video, DECT/CAT-iq, VoIP and analog voice. http://www.lantiq.com/hnx

LOW NOISE, HIGH-OUTPUT XPON VIDEO RECEIVER

supply in most xPON applications. RFRX8888’s ultra-low noise performance, combined with high output power, extends the performance and lifetime of wired networks by improving the link margin and/or allowing more passive optical splits. For FTTP applications requiring +5 VDC power supply operation, the RFRX8890 video receiver is also available. Features include: •+12V Single Supply Operation •On-Die Bias Circuitry Reduces Cost and Board Area •Best-in-Class Low Noise (<3.0 pA/rtHz Equivalent Input Noise Current) •Low Power: 1.4 W at +12V •Best-in-Class +23 dBmV per Channel RF Output Capability •Linearity Better Than -63 dBc CSO and -66 dBc CTB at +23 dBmV RF Out Per Channel (79-NTSC Equivalent Channels) •48 MHz to 1002 MHz Operational Bandwidth •30 dB AGC Range http://www.rfmd.com

SG384 RF SIGNAL GENERATOR Stanford Research Systems, Inc. Introducing the SG384, a 4 GHz RF Signal Generator from SRS. It offers a DC to 4 GHz frequency range with 1 +Hz resolution, AM, FM, and PM, with -116 dBc/Hz phase noise at 20 kHz offset from 1 GHz, full octave frequency sweeps, an OCXO timebase and standard RS232, GPIB and Ethernet interfaces. Options include clock outputs, analog I/Q inputs and a rubidium timebase. http://www.thinkSRS.com

RF Micro Devices RFMD’s new RFRX8888 video receiver performs transimpedance amplification of the differential input from a high performance 1550nm optical wavelength photo detector (PD), all with best-in-class noise performance. This IC's output is linear low distortion RF from 48 MHz to 1002 MHz. RFRX8888 is ideal for 1550nm optical wavelength RF analog or digital overlay video receive circuitry employed in xPON FTTP ONT triplexer and quadplexer modules. Its first stage features integrated bias circuitry simplifying external-to-IC end product design and lowering overall end product assembly cost. Optimized for operation from a +12 VDC power supply with a highly efficient power consumption of just 1.4 W, it eliminates the need for a supplemental ONT power

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Msample per second. It comes with a robust, interchangeable solid-state drive with one Tbyte of storage capacity and a recording rate of 270 Mbyte per second. The R&S IQR I/Q data recorder records digital RF signals in realtime. Thanks to its unique combination of speed, compactness and robustness, it is ideal for use in drive tests in broadcasting and mobile radio networks. For instrument tests or electronic component testing, the recorder can be used to supply previously generated test signals. In addition, broadband spectra or sporadic signals can be recorded in realtime for later offline analysis. To obtain a continuous analysis system for digital RF signals, the user can connect the data recorder with either a spectrum or radio network analyzer and with a signal generator from Rohde & Schwarz via the digital I/Q interface. This I/Q interface simplifies both parameter exchange between the instruments and the setup of the data recorder. During configuration, the user can access several trigger modes for the start/stop function that range from manual quick start to the triggering of recording via a previously entered I/Q signal level. The integrated Ethernet interface permits remote control of the instrument as well as the transfer of the measurement data via LAN. Two extra USB interfaces on the front panel and a touch screen round out the user-friendly concept of the data recorder. http://www.rohde-schwarz.com

MODEL-DRIVEN CONFIGURATION MANAGEMENT Tail-f Systems

DIGITAL I/Q

DATA RECORDER

Rohde & Schwarz Rohde & Schwarz introduuced the R&S IQR digital I/Q data recorder at electronica in Munich. The recorder can record, store and replay digital RF signals loss-free and in realtime over the I/Q interface developed by Rohde & Schwarz. When used in combination with RF scanners, generators and network analyzers from Rohde & Schwarz, the recorder completes a high-performance, continuous analysis system for digital RF signals. This system will prove to be of particular benefit for users in broadcasting, mobile radio, aerospace & defense, and the automobile industry. The compact recorder – in half 119-inch format – currently offers transmission rates of up to 66

Tail-f Systemshas announced the first model-driven configuration management application for provisioning Carrier Ethernet services. NCS for Carrier Ethernet will benefit both service providers and networking equipment providers by enabling the activation of complex services in less time and with fewer resources. NCS also radically simplifies the development of new and enhanced management systems, allowing developers to bring new products to market much faster. NCS is a general applications framework for building configuration management systems. NCS for Carrier Ethernet extends the value of NCS by incorporating service and device models plus a Web UI optimized for implementing Carrier Ethernet management systems. http://www.tail-f.com

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CONFERENCE CALENDAR MARCH

Phoenix Park, Korea. http://www.icact.org/

2011 FEBRUARY • NTMS 2011 - 4th Int’l. Conference on New Technologies, Mobility and Security, 7-10 Feb. Paris, France. http://www.ntms-conf.org/innovative-pro__________________________ jects.htm ______

• ONDM 2011 - 15th Int’l. Conference on Optical Networking Design and Modeling, 8-10 Feb. Bologna, Italy. http://www.ondm2011.unibo.it/

• ICACT 2011 - 13th Int’l. Conference on Advanced Communication Technology, 13-16 Feb.

z IEEE CogSIMA 2011 - IEEE Conference on Cognitive Methods in Situation Awareness and Decision Support, 22-24 Feb. Miami, FL. http://www.ieee-cogsima.org

• ISWPC 2011 - Int’l. Symposium on Wireless Pervasive Computing, 23-25 Feb. Hong Kong, China. http://www.iswpc.org/2011/

• WSA 2011 - Int’l. ITG Workshop on Smart Antennas, 24-25 Feb. Aachen, Germany. http://www.wsa2011.rwth-aachen.de/

z OFC/NFOEC 2011- Optical Fiber Communication Conference, 6-10 March Los Angeles, CA. http://www.ofcnfoec.org/

z IEEE WCNC 2011 - IEEE Wireless Communications and Networking Conference, 28-31 March Cancun, Mexico. http://www.ieee-wcnc.org/

• ICCIT 2011 - Int’l. Conference on Communications and Information Technology, 28-31 March Aqaba, Jordan. http://iccit-conf.org/

APRIL

z Communications Society portfolio events are indicated with a diamond before the listing; • Communications Society technically co-sponsored conferences are indicated with a bullet before the listing. Individuals with information about upcoming conferences, calls for papers, meeting announcements, and meeting reports should send this information to: IEEE Communications Society, 3 Park Avenue, 17th Floor, New York, NY 10016; e-mail: [email protected]; ____________ fax: +1-212-705-8996. Items submitted for publication will be included on a space-available basis.

z IEEE ISPLC 2011 - 15th IEEE Int’l. Symposium on Power Line Communications and Its Applications, 3-6 April Udine, Italy. http://www.ieee-isplc.org/

____________

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CONFERENCE CALENDAR z IEEE INFOCOM 2011 - IEEE Conference on Computer Communications, 10-15 April Shanghai, China. http://www.ieee-infocom.org

• IEEE RFID 2011 - IEEE Int’l. Conference on RFID 2011, 12-14 April Orlando, FL. http://ewh.ieee.org/mu/rfid2011/

• WTS 2011 - Wireless Telecommunications Symposium 2011, 13-15 April New York, NY. http://www.csupomona.edu/~wtsi/wts/index.h tm __

• IIT 2011 - Int’l. Conference on Innovations in Information Technology, 25-27 April Dubai, United Arab Emirates. http://www.it-innovations.ae/iit10/index.html

• ISPS 2011 - 10th Int’l. Symposium on Programming and Systems, 25-27 April Algiers, Algeria. http://www.isps2011.dz/

MAY • IEEE SARNOFF - 34th Sarnoff Symposium 2011, 2-4 May Princeton, NJ. http://sarnoff-symposium.ning.com/

• MC-SS 2011 - 8th Int’l. Workshop on Multi-Carrier Systems and Solutions, 3-4 May Herrsching, Germany. http://www.mcss.dlr.de/

z IEEE DySPAN 2011 - IEEE Int’l. Symposium on Dynamic Spectrum Access Networks, 3-6 May Aachen, Germany. http://www.ieee-dyspan.org/

• ICT 2011 - 18th Int’l. Conference on Telecommunications, 8-11 May Ayia Napa, Cyprus. http://www.ict2011.org/

z IEEE CQR 2011 - 2011 Annual IEEE CQR Int’l. Workshop, 10-12 May

Arequipa, Peru. http://conatel.ucsp.edu.pe/

z IEEE/IFIP IM 2011 - 12th IFIP/IEEE Int’l. Symposium on Integrated Network Management, 23-27 May Dublin, Ireland. http://www.ieee-im.org/

JUNE z IEEE IWQoS 2011 - 18th IEEE Int’l. Workshop on Quality of Service, 5-7 June San Jose, California. http://www.ieee-iwqos.org/

z IEEE ICC 2011 - IEEE Int’l. Conference on Communications, 5-9 June Kyoto, Japan. http://www.ieee-icc.org/2011/

• IEEE POLICY 2011 - IEEE Int’l. Symposium on Policies for Distributed Systems and Networks, 6-8 June Pisa, Italy. http://www.ieee-policy.org/

z IEEE CAMAD 2011 - IEEE Int’l. Workshop on Computer-Aided Modeling Analysis and Design of Communication Links and Networks 2011, 10-11 June

Salt Lake City, Utah. http://www.ieee-secon.org/2011/

• IEEE ITMC 2011 - IEEE Int’l. Technology Management Conference, 27-30 June San Jose, CA. http://www.ieee-itmc.org/

z IEEE ISCC 2011 - 16th IEEE Symposium on Computers and Communications, 28 June-1 July Kerkyra, Greece. http://www.ieee-iscc.org/2011/

• ICL-GNSS 2011 - Int’l. Conference on Localization and GNSS 2011, 29-30 June Tampere, Finland. http://www.icl-gnss.org/2011/index.php

JULY z IEEE HPSR 2011 - 12th IEEE Int’l. Conference on High Performance Switching and Routing, 4-6 July Cartagena, Spain. http://www.ieee-hpsr.org/

• OECC 2011 - 16th Opto-Electronics and Communications Conference, 4-8 July Kaoshlung, Taiwan. http://www.oecc2011.org/

Kyoto, Japan. http://www.nprg.ncsu.edu/camad/

z IEEE ICME 2011 - 2011 IEEE Int’l. Conference on Multimedia and Expo, 11-15 July

z IEEE HEALTHCOM 2011 - 13th IEEE Int’l. Conferece on e-Health Networking, Application & Services, 13-15 June

Barcelona, Spain. http://www.icme2011.org/

Columbia, MO. http://www.ieee-healthcom.org/

• ConTEL 2011 - 11th Int’l. Conference on Telecommunications, 15-17 June Graz, Austria. http://www.contel.hr/

• ICUFN 2011 - 3rd Int’l. Conference on Ubiquitous and Future Networks Dalian, China. http://www.icufn.org/main/

AUGUST • ICCCN 2011 - Int’l. Conference on Computer Communications and Networks 2011, 1-4 Aug. Maui, Hawaii. http://www.icccn.org/ICCCN11/

z ATC 2011 - 2011 Int’l. Conference on Advanced Technologies for Communications, 3-5 Aug. Da Nang City, Vietnam. http://rev-conf.org/

Naples, FL. http://committees.comsoc.org/cqr/

z IEEE CTW 2011 - IEEE Communication Theory Workshop, 20-22 June

• ICADIWT 2011 - 4th Int’l. Conference on the Applications of Digital Information and Web Technologies, 46 Aug.

z IEEE ICSOS 2011 - IEEE Int’l. Conference on Space Optical Systems and Applications, 11-13 May

Sitges, Spain. http://www.ieee-ctw.org

Stevens Point, WI. http://www.dirf.org/DIWT/

Santa Monica, CA.

z IEEE SECON 2011 - 8th Annual IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks, 27-30 June

z IEEE P2P 2011 - IEEE Int’l. Conference on Peer-to-Peer Computing, 31 Aug.-2 Sept.

http://icsos2011.nict.go.jp/

• CONATEL 2011 - 2nd Nat’l. Conference on Telecommunications (Peru),

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17-20 May

Tokyo, Japan. http://p2p11.org/

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CONFERENCE CALENDAR (Continued from page 17) z IEEE EDOC 2011 - 15th IEEE Int’l. Enterprise Distributed Object Computing Conference, 31 Aug.-2 Sept. Helsinki, Finland. http://edoc2011.cs.helsinki.fi/edoc2011/

SEPTEMBER • ITC 23 2011 - 2011 Int’l. Teletraffic Congress, 6-8 Sept.

Houston, TX. http://www.ieee-globecom.org/2011/

Las Vegas, NV. http://www.ieee-ccnc.org/

2012

MARCH

JANUARY z IEEE CCNC 2012 - IEEE Consumver Communications and Networking Conference, 8-11 Jan.

z IEEE INFOCOM 2012 - IEEE Int’l. Conference on Computer Communications, 25-30 March Orlando, FL. http://www.ieee-infocom.org/2012/

San Francisco, CA. http://www.itc-conference.org/2011

z IEEE PIMRC 2011 - 22nd IEEE Int’l. Symposium on Personal, Indoor and Mobile Radio Communications, 11-14 Sept. Toronto, Canada. http://www.ieee-pimrc.org/2011/

• ICUWB 2011 - 2011 IEEE Int’l. Conference on Ultra-Wideband, 14-16 Sept.

Realize a new level of confidence in LTE PHY design

Bologna, Italy. http://www.icuwb2011.org/

z IEEE GreenCom 2011 - Online Conference, 26-29 Sept. Virtual. http://www.ieee-greencom.org/

OCTOBER • DRCN 2011 - 8th Int’l. Workshop on Design of Reliable Communication Networks, 10-12 Oct. Krakow, Poland. http://www.drcn2011.net/index.html

NOVEMBER • ISWCS 2011 - 8th Int’l. Symposium on Wireless Communication Systems

Verification

Golden Reference

Performance Testing

LTE Toolbox/Blockset for MATLAB®/Simulink® Comprehensive set of functions/blocks modeling the LTE physical layer transmit and receive processing

Aachen, Germany. http://www.ti.rwth-aachen.de/iswcs2011/

Supports FDD and TDD duplexing

• COMCAS 2011 - 2011 IEEE Int’l. Conference on Microwaves, Communications, Antennas and Electronic Systems, 7-9 Nov.

Channel estimation, synchronization and MIMO receivers (ZF,MMSE,SFBC)

Tel Aviv, Israel. http://www.comcas.org/

z MILCOM 2011 - Military Communications Conference, 7-10 Nov. Baltimore, MD. http://www.milcom.org/index.asp

Standard compliant propagation channel models (EPA, EVA, ETU, Moving, HST) Product roadmap includes releases through LTE-Advanced GUI based tools for LTE conformance test simulation and ARB waveform generation Extensive help, background documentation and demo set including HARQ and MIMO performance, PDCCH/DCI decoding and MIB/SIB recovery

Evaluate the complete solution at

www.steepestascent.com/lte/mathworks

DECEMBER z IEEE GLOBECOM 2011 - 2011 IEEE Global Communications Conference, 5-9 Dec.

www.steepestascent.com [email protected]

(UK): +44 141 552 8855 (US): +1 805 413 4127

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PRODUCT SPOTLIGHTS GL Communications

Vectron The solution for all applications with no room for compromise in g-sensitivity, noise or stability performance but small size is required. Ideal for equipment used in harsh environments such as tactical weapons, avionics and portable equipment. The 508 product family of oscillators offers the industry's leading aging, stability, phase noise and g-sensitivity in a miniature 9 x 14 package. http://www.vectron.com

GL’s PacketProbe™ is an advanced CPE-based VoIP monitoring, reporting and diagnostic appliance. PacketProbe™ passively monitors VoIP traffic carried over the WAN/LAN by producing per call and per-stream voice quality metrics. Call Detail Records (CDR’s) along with voice quality statistics and other vital diagnostic information provide network managers immediate visibility into service quality, call volumes and call details. Service providers are able to rapidly drill down and diagnose voice related issues. Standards based Real-time Monitoring, Reporting and Diagnostic tools fit seamlessly into any existing standards based Management or Reporting environment, such as SNMP and RADIUS. Vital voice call quality statistics, Call Detail Records and Quality of Service metrics are available at the end of each call. Optionally GL offers its own Monitoring and Reporting System, PacketScanWEB™. http://www.gl.com/packetprobe.html

Silicon Labs Learn how to simplify your timing design using glitch-free frequency shifting to address low-power design challenges and the complexity of generating a wide range of frequencies in consumer electronics applications such as audio, video, computing or any application that requires multiple frequencies. Download this in-depth white paper from Silicon Labs. http://www.silabs.com/frequency-shifting

RSoft Design

Omicron Labs Omicron Labs’ Vector Network Analyzer Bode 100 now provides a 360° view on switched mode power supplies and voltage regulators. In combination with the Picotest Signal Injector series all key parameters such as Stability, PSRR, cross-talk, reverse transfer and impedance can be measured easily and accurately. http://www.omicron-lab.com http://www.picotest.com

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RSoft releases version 5.2 of its award winning Optical Communication Design Suite OptSim and its multimode companion ModeSYS. The latest release features enhanced modeling capabilities for 100G Coherent PM-QPSK, Polarization induced all-optical switching, Bi-directional Ethernet in the First Mile, Interferometric systems, mode-coupling based Multimode systems, and Plastic Optical Fiber systems. http://www.rsoftdesign.com

GL Communications GL’s MAPS™(Message Automation & Protocol Simulation)-LTE supports scripted LTE simulation with the ability to simulate entities such as eNodeB (Evolved Nodeb), MME (Mobility Management Entity), SGW (Serving Gateway), and PGW (Packet Data Network Gateway). Supported interfaces include S1, S11 and S5/S8 (LTES1 and LTE-eGTP). Support for other interfaces such as S4, S11, and S12 is coming soon. The application gives the users the unlimited ability to edit S1-AP/NAS and eGTP-C (Evolved GPRS Tunneling Protocol for Control Plane (eGTP-c) messages and control scenarios (message sequences). http://www.gl.com/maps-lte.html

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Global

Newsletter February 2011

IEEE Healthcom 2010: “Ambient Assisted Living” for Better Health By Norbert Noury, Healthcom 2010 General Chair, University of Lyon, France Telecommunications and networks are well recognized enabling technologies for telemedicine applications in remote and rural locations, but are also more and more becoming facilitating technologies for continuous health monitoring out of hospital, for p-health at home, and during various human activities, professional, leisure, or sports. A new field of investigation, never entered before, is now made possible: to continuously collect health information with context awareness. The field of e-health is also a remarkable melting point which gives the opportunity to bring together interested parties from around the world working in the various fields of healthcare and engineering to exchange ideas, discuss innovative and emerging solutions, and develop collaborations around operational projects. The 12th International Conference on e-Health Networking, Application & Services, Healthcom2010, was held in Lyon, France, on 1–3 July 2010. It was an important forum for discussions on e-health projects sponsored by world bodies such as the European Community (FP6 and FP7 European projects on AAL and e-inclusion, etc.). Each year, a broad variety of topics are presented at Healthcom, addressing the different levels of e-Health, from technologies to applications: •Network and Communications Infrastructures and Architectures for Healthcare Delivery •New Models for Healthcare Delivery •e-Health for Public Health •e-Health for Aging •m-Health •Field Applications •Education •Ethics The conference gathered more than 130 attendees, coming from 35 countries, including clinicians, IT professionals, researchers, healthcare solutions vendors, and consultants. About 90 papers were presented, addressing a broad variety of topics within e-Health. The submission rate was high, with 122 papers out of which 62 were selected for presentation, included in the Proceedings accessible through IEEEXplore, and six selected papers are to appear in a special issue of the International Journal of e-Health and Medical Communications (Professor Joel Rodrigues, Editor-in-Chief). The first keynote speaker, Professor Louis Lareng, Director of the European Telemedicine Society, reviewed the history of developing telemedicine in Europe since the 1950s. Dr Loukianos Gatzoulis, from the European Commission in Brussels, presented the goals of the EU in supporting ehealth, societal and economical. Jean Schwoerer, from Orange Labs, depicted the current normalization efforts in the field of

body sensor networks. Professor André Dittmar from CNRS in Lyon demonstrated the need for new ubiquitous body sensors to support e-health efforts and deployments. The HC10 was articulated around three main sessions, “Enabling Technologies,” “Enabling Information Systems,” and “Enabling Applications.” The variety and density of information were very high. Some main points are the followings. Body sensor networks allow collecting and aggregating data from several sensors in a mobile context. This mobility offers continuous monitoring of patient status, imrpoving patients’ quality of life. Existing femtocellular network resources, already available on site, may be used for rapid provisioning of mobile broadband data connectivity indoors for emergency telemedicine applications. This approach results in a reduction in service outage rates. Remote telemonitoring of elderly people in their own homes is a major challenge to face the fast growing population of elderly people. Health Smart Homes allow monitoring the behavior of a person with non-intrusive sensors. The major trends in the activity reflect the global homeostasis of the subject. High-level decision tools are used to classify scenarios of daily living and eventually to build an index of activities of daily living. As these smart homes will benefit people in preventing loss of autonomy, disabled people or elderly people with cognitive deficiencies, it is essential to facilitate their interactions with Smart Homes through dedicated interfaces, such as systems reactive to vocal orders. Audio recognition is also a promising way to ensure detection of distress situations. E-healthcare and telemedicine applications, when deployed to provide healthcare to remote locations in developing countries, must carefully take into account the existing healthcare and communications facilities, but also socio-economic conditions of populations. Telemedicine can also allow deployment of real-time disease surveillance and notification systems in developing countries. The communication technologies, adopting global standards for structured messages (SMS, email, web), will reduce the delays in communicating field data to central epidemiology units, which can therefore detect disease outbreaks in a timely manner, and allow health system to effectively respond and mitigate the consequences for populations. The domain of e-health is currently demonstrating high vitality. It is a living laboratory for cooperation between the fields of health and engineering. It is also a chance to better understand the health of humans in their living contexts. I want to thank Assistant Professor Pradeep Ray, director of the Asia-Pacific Ubiquitous Healthcare Research Centre (APuHC) at the University of New South Wales, who kindly invited me to organize IEEE Healthcom 2010.

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1st FOKUS FUSECO Forum 2010, Berlin, Germany By Prof. Dr. Thomas Magedanz, General Chair, TU Berlin/Fraunhofer FOKUS, Germany The First international FOKUS FUSECO Forum (FFF) on “Business and Technical Challenges of Seamless Service Provision in Converging Next Generation Fixed and Mobile Networks” was held in Berlin, Germany, on 14-15 October 2010 and was attended by around 150 experts from industry and academia. The FFF represents a technologically focused follow-up to the famous FOKUS IMS Workshop series, as the future role of IP Multimedia Subsystem (IMS) in mobile and fixed next-generation networks (NGNs) deserves some critical considerations in regard to slow industry adoption and rapidly emerging new control protocols and platforms from the Internet domain. There is no doubt that IMS has consolidated the various views on Session Initiation Protocol (SIP) and Diameter-based NGNs, and many standards have been established for voice over IP (VoIP), rich communications services (RCS), and IPTV. But there is lot of pressure from emerging over-the-top (OTT) applications originating from the Internet, challenging IMS business case calculations and extensive deployments beyond NGN VoIP. In addition, IMS is limited to SIP-based control and thus HTTP (Hypertext Transport Protocol) and other protocol-based applications, forming the majority of current fixed and mobile broadband traffic are out of control. Here the 3GPP Evolved Packet Core) (EPC) has the potential to emerge as a common control platform for any IP application. From the technical maturity and global recognition points of view, EPC stands today where IMS stood five years ago; thus, it is time to launch a new workshop series to create global awareness in academia and industry about this promising technology. Thus, the FFF discussed for two days the relationship between the EPC, IMS, and OTT approaches. The first day started with a technical tutorial about Long Term Evolution (LTE) and EPC standards, and introduced the Fraunhofer HHI LTE-Advanced Testbed and Fraunhofer FOKUS OpenEPC toolkit, which have been integrated into the Future Seamless Communication (FUSECO) Playground, the globally first open testbed uniting wireless LANs, 3G networks, LTE, and EPC technologies for early prototyping of new seamless applications. Practical demonstrations including seamless handovers of Skype and video services with quality of service assurance from the FUSECO Playground and an OpenEPC Release 2 preview were also provided to the audience. The second day featured a conference with presentations from various international network operators and service providers. A vendor panel session and an associated exhibition presented the state of the art and upcoming products in this field. In the following some more details are provided for both days. The tutorial “Understanding the Next Generation of Mobile Broadband Communications: LTE and EPC Concepts, Architectures, Protocols and Applications” on the first day was presented by Dr. Thomas Haustein, Fraunhofer HHI, and Prof. Dr. Thomas Magedanz, Fraunhofer FOKUS and TU Berlin. It started by pointing out the continuously increasing mobile data traffic demand and motivated the need for LTE, EPC, and IMS technologies in order to allow smooth evolution from existing circuit- and packet-switched mobile networks to a next-generation mobile network. A session about LTE presented details about the radio part, covering standards and architectures, and gave an outlook on LTE-Advanced. The correlated network part was covered in the following session by introducing EPC terminology, key concepts, and architecture, as well as the related Third Generation Partnership Project (3GPP) standards. Subsequently, potential applications and related platforms were discussed, including operator IMS platforms for voice over LTE (VoLTE), as well as over the top Internet service platforms. An outlook onto global Future Internet research and related application areas has concluded this tutorial section. The tutorial

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The 1st International FOKUS FUSECO Forum (FFF) was attended by approximately 150 experts from industry and academia. ended with a presentation of the experiences from the Berlin LTE-Advanced testbed, the OpenEPC testbed toolkit, and the FUSECO Playground. Demonstrations during the breaks showed current proof of concept realizations, including seamless handovers between LTE-A and WLAN, service composition, and transparent mobility. The demonstrations covered essential challenges in the scope of LTE and EPC, and illustrated practical solutions based on these emerging technologies. On day 2 the conference started with a session on “Competing Mobile Broadband Access Network Technologies” chaired by Thomas Haustein, Fraunhofer HHI, and addressed challenges emerging with the introduction of LTE and EPC. The second session, “Access Network Integration and Service Enabling,” chaired by Hans Schotten, University of Kaiserslautern, addressed technical problems during the deployment of EPC into existing network infrastructures, in particular IMS roaming and different QoS signaling, as well as the complex IMS and EPC interoperability, which might take until 2014/2015. A vendor panel, “Standards, Products, and Business Cases for Future Seamless Communication,” chaired by Thomas Magedanz, TU Berlin, discussed the LTE business case, voice over LTE, the importance of open application programming interfaces (APIs) for VoLTE and RCS, and so on. The fourth session, “FUSECO Telco Applications: Voice, RCS and More,” chaired by Hans Joachim Einsiedler, Deutsche Telekom Laboratories, addressed mobile broadband services and M2M opportunities, and application challenges regarding fast deployment of web services and slow agreement on interoperability. The overall tenor forecasts no LTE/mobile broadband killer application. The last session, “FUSECO OTT Applications: Beyond Smart Bit Pipes,” chaired by Thomas Michael Bohnert, SAP Research, presented opportunities for wholesale and enterprise operators, OTT services, and the usability of LTE for vehicles. VoIP in mobile networks is growing in acceptance, increasingly challenging the operators around the globe. As Facebook has now announced interworking with Skype, the question of using Facebook as the main interface for launching new applications in the future has been raised. Alongside the workshops and conference, vendor exhibitions showed 4G Subscriber Data Management/Communications as a Service, Enhancements of Mobility Management for the 3GPP EPS — smart mobile devices in a dense wireless network environment, IBM Software Strategy for CSPs — start planning and implementing smarter communications systems, and smart networks for user-centric broadband. In addition, the newest (Continued on Newsletter page 4)

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Internet for Everybody in Spain: The 1 Mb/s Universal Service By Ana Vázquez Alejos, Rafel Asorey Cacheda and Felipe José Gil Castiñeira, University of Vigo, Spain Universal telecom service is a concept defined at the European level with the objective to guarantee all citizens the right of access to a defined set of basic electronic communications services, independent of their geographical location, with a minimum quality and at a reasonable price. Until now, in Spain, only a functional Internet access was considered as a service offered by the public phone wired network, with download speeds of 256 kb/s. During October 2009, the Spanish Ministry of Industry performed a public survey [1] to determine the minimum features that would require the Internet universal service to be updated to the growing needs of the Information Society. The survey outcomes concluded that choosing broadband access with a bit rate of 1 Mb/s would conciliate the current demands of the Information Society and the requirements to impel the modernization of the digital infrastructures. As a consequence, the Minister of Industry announced that the universal service would include the 1 Mb/s downlink broadband connection in 2011 as a minimum requirement to increase competitiveness in the broadband business. Recently, during the celebration of CEBIT 2010 in Hannover, Spanish Government President Mr Rodriguez Zapatero confirmed this aim. The operator in charge of providing the universal service will be selected during 2010. The inclusion of the broadband access with a minimum downlink speed of 1 Mbps makes Spain to go in head of the digital European policies. This actuation can be considered an epilogue to the AVANZAPEBA plan [2], designed to extend the penetration of the broadband access in Spain and deployed by the Government from 2005 to 2008. Now, that the plan is over, it is time to measure the achievements before designing the new telecom policy. We can compare the Spanish case to other European countries such as Finland. Traditionally, the latter has been found positioned in first place of the pro-right career in telecommunications, reaching the point of including in its constitution the right of a nationwide 1 Mb/s broadband connection provided by any kind of technology, hoping to reach the speed of 100 Mb/s by 2015. However, it was not Finland but Switzerland that, in 2008, defined broadband access as a connection of 100 kb/s/600 kb/s for up-/downlink speeds. Thus, Spain will become the third European country adopting a quantitative definition of broadband access. Despite this, the reality and the political intentions follow paths dangerously separated. The European Competitive Telecommunications Association (ECTA) Broadband Scorecard is a recognized benchmark being used regularly by industry, the European Commission, national regulators, and institutions. Biennially, ECTA collates and publishes data tracking the progress on broadband penetration and local loop unbunding in the 25 European Member States [3]. Some of the latest published statistics are plotted in Figure 1. According to this source, goals seem not to be reached, placing Spain under the average of European countries in broadband penetration, with a penetration rate of 21 percent, which is two points under the EU average placed at 23.5 percent. Along the same lines, a recent report published by the Regional Government of Galicia (Northwestern Spain) demonstrated that this situation is even more critical [4]. The determining factor of this circumstance can be found in the situation experienced by rural areas, which present 70 percent nonexistent or low-quality network access, under 512 kb/s, even after an investment of €225,000,000 provided by public funds. The same happens in other Spanish regions, showing a deep imbalance between urban and rural state areas.

2009 April total connections per technology for Spain including radio [2]. Closer insight into tje data provided by ECTA reveals that Sweden remains Europe’s fiber leader, with 7.5 percent of the population benefiting from high-speed modern access lines compared to an average of just 0.4 percent across the EU. Despite “regulatory holidays” for incumbents in countries such as Germany and Spain, the survey showed little evidence of increased fiber deployment in those countries. It also highlights a strong link between effective economic regulation and investment levels in the telecom sector, where a regulatory framework helps alternative operators compete against the national incumbent, but also does not encourage investments on new infrastructure since new deployments require many resources and are only profitable in the long term. The EU presidency by part of Spain in 2010 would seem to be a suitable moment to support the consideration of broadband Internet as an indispensable service in the Information Society. However, 1 Mb/s may not be enough and can hardly be considered broadband Internet in 2010. Moreover, no one has explained how this service will be provided since there are large areas in Spain without any kind of Internet access. And the most important thing is the need to define how the provision of this service will be financed. Probably, without public funds, it will not be possible to accomplish these goals, although achieving them would doubtlessly place Spain on top of the most developed information societies.

References [1] [2] [3] [4]

http://www.mityc.es http://www.planavanza.es http://www.ectaportal.com http://imit.xunta.es/

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Distinguished Lecturer Tour of Bhumip Khasnabish in India By Deergha Rao Korrai, Chair, Communications and Signal Processing Societies Joint Chapter, Hyderabad, India The Distinguished Lecturer Program is one of the best initiatives of the IEEE Communications Society. It brings distinguished experts to give lectures at Chapters on all continents. A DL tour of Dr. Bhumip Khasnabish, ZTE, United States, was held in India in July 2010. Lectures entitled “Services over IP: Implementation Options and Challenges” and “Converged Services and a New Generation of Networking” were given in India from 9 July to 17 July 2010 with the following schedule: 1) Mumbai, 9 July 2010 (two lectures); 2) Pune, 10 July, 12 July 2010 (two lectures); 3) Hyderabad, 13 July 2010 (two lectures); 4) Kharagpur, 15 July 2010 (one lecture); 5) Kolkata, 17 July 2010 (one lecture). Dr. Khasnabish’s lectures in Hyderabad were organized by the Communications and Signal Processing Societies Joint Chapter of the IEEE Hyderabad Section, and his accommodation and travel within Hyderabad were arranged by TCS Hyderabad. “Services over IP: Implementation Options and Challenges” is a tutorial and was held on 13 July 2010 at the Research and Training Unit for Navigational Electronics (NERTU) auditorium, University College of Engineering, Osmania University, Hyderabad from 9 a.m. to 1 p.m. There were 55 audience members for the tutorial, including students, research scholars, participants from industry, and faculty of colleges. During this lecture, issues related to mouth-to-ear delay calculation or estimation, GPS integration, location services, current status and future infrastructure deployment, speed of IPTV and the status of current compression technology, cooperating multimode devices, net enabled health services, security issues like DRM, Skype, and emerging trends were raised by the participants. These were well answered by the speaker; furthermore, he emphasized the need for interoperability, standardization, and protocol integration. “Converged Services and a New Generation of Networking” was held on 13 July 2010 at the Gadavari auditorium, TCS, Dec-

Global Newsletter www.comsoc.org/pubs/gcn _______________

STEFANO BREGNI Editor Politecnico di Milano - Dept. of Electronics and Information Piazza Leonardo da Vinci 32, 20133 MILANO MI, Italy Ph.: +39-02-2399.3503 - Fax: +39-02-2399.3413 Email: ___________ [email protected], [email protected] _________ IEEE COMMUNICATIONS SOCIETY

KHALED B. LETAIEF, VICE-PRESIDENT CONFERENCES SERGIO BENEDETTO, VICE-PRESIDENT MEMBER RELATIONS JOSÉ-DAVID CELY, DIRECTOR OF LA REGION GABE JAKOBSON, DIRECTOR OF NA REGION TARIQ DURRANI, DIRECTOR OF EAME REGION NAOAKI YAMANAKA, DIRECTOR OF AP REGION ROBERTO SARACCO, DIRECTOR OF SISTER AND RELATED SOCIETIES REGIONAL CORRESPONDENTS WHO CONTRIBUTED TO THIS ISSUE

THOMAS M. BOHNERT, SWITZERLAND (THOMAS [email protected]) _____________________ JOSEMARIA MALGOSA SANAHUJA, SPAIN (_______________ [email protected]) JOEL RODRIGUES, PORTUGAL (JOELJR @IEEE.ORG) __________ EWELL TAN, SINGAPORE (____________ [email protected])

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Mr.MGPL Narayana(Hyderabad section chair, third from left), Dr.Bhumip Khasnabish (fourth from left), Dr.Deergha Rao Korrai (chapter chair, fifth from left) and other IEEE volunteers of the Hyderabad section after the lecture at the Godavari auditorium of TCS. can Park,Hi-Tech City, Hyderabad, from 5 p.m. to 7 p.m. There were 154 audience members for this lecture, including students, research scholars, participants from industry, and faculty of universities and colleges. In this lecture the speaker answered issues raised by participants related to protocols and infrastructure, IETF.org, streaming media, VoIP, IPTV, packet delay, packet losses, acceptable delays (< 150 ms), the difference between Internet phone and IP phone, telemedicine prospects in India, IPv6 adoption, QoS, QoE, WiMAX, LTE, virtual device (embedded) services, and more. The single biggest phenomenon that is transforming the global telecom industry is convergence. Internet users are now exposed to different modes of communication than basic voice telephony. Communication now includes pictures and videos, and is not limited to person-to-person communication; communities and user groups are being created, and information exchange is not limited to and from people known to each other. Content is driving service subscription, and identifying the right content in the right format at the right cost and delivering it in a secure manner to any kind of business model for the communication industry are the main issues. Convergence has been visible on the horizon for the last couple of years, but has yet to arrive in developing countries in a major way. The lecture focused on convergence of communication services like data, voice, and video in IP-based networks. The speaker stressed the importance of quality of experience (QoE) apart from quality of service (QoS) in IPTV user judgment and acceptance. Experience needs to be preserved as video traffic is transported across IP infrastructure. Service providers need IP-based next-generation network (IP-NGN) infrastructure solutions that are intelligent and video-aware. An outstanding video experience requires excellent solutions in the customer home to decode, decrypt, share, and display the content the way it was intended. In feedback, the participants expressed satisfaction with the event organization, suggesting increasing the time for these kinds of lectures, more explanations of security, and some demonstrations using MATLAB interfacing and Labviews.

FOKUS FUSECO FORUM/continued from page 2 toolkits from Fraunhofer FOKUS, the universal client framework myMONSTER TCS (www.opensoaplayground.org/tcs) and the newest release of the OpenEPC toolkit (www.openepc.net), were presented. This new forum will be continued next year in November 2011 to establish a regular meeting point for international researchers from academia and industry (www.fuseco_________ forum.org/2011). __________

Global Communications Newsletter • February 2011

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Anritsu Optical Time Domain Reflectometers

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Editor-in-Chief Steve Gorshe, PMC-Sierra, Inc. (USA) Associate Editor-in-Chief Sean Moore, Centripetal Networks (USA) Senior Technical Editors Tom Chen, Swansea University (UK) Nim Cheung, ASTRI (China) Nelson Fonseca, State Univ. of Campinas (Brazil) Torleiv Maseng, Norwegian Def. Res. Est. (Norway) Peter T. S. Yum, The Chinese U. Hong Kong (China) Technical Editors Sonia Aissa, Univ. of Quebec (Canada) Mohammed Atiquzzaman, U. of Oklahoma (USA) Paolo Bellavista, DEIS (Italy) Tee-Hiang Cheng, Nanyang Tech. U. (Rep. Singapore) Jacek Chrostowski, Scheelite Techn. LLC (USA) Sudhir S. Dixit, Nokia Siemens Networks (USA) Stefano Galli, Panasonic R&D Co. of America (USA) Joan Garcia-Haro, Poly. U. of Cartagena (Spain) Vimal K. Khanna, mCalibre Technologies (India) Janusz Konrad, Boston University (USA) Abbas Jamalipour, U. of Sydney (Australia) Deep Medhi, Univ. of Missouri-Kansas City (USA) Nader F. Mir, San Jose State Univ. (USA) Amitabh Mishra, Johns Hopkins University (USA) Sedat Ölçer, IBM (Switzerland) Glenn Parsons, Ericsson Canada (Canada) Harry Rudin, IBM Zurich Res.Lab. (Switzerland) Hady Salloum, Stevens Institute of Tech. (USA) Antonio Sánchez Esguevillas, Telefonica (Spain) Heinrich J. Stüttgen, NEC Europe Ltd. (Germany) Dan Keun Sung, Korea Adv. Inst. Sci. & Tech. (Korea) Danny Tsang, Hong Kong U. of Sci. & Tech. (Japan) Series Editors Ad Hoc and Sensor Networks Edoardo Biagioni, U. of Hawaii, Manoa (USA) Silvia Giordano, Univ. of App. Sci. (Switzerland) Automotive Networking and Applications Wai Chen, Telcordia Technologies, Inc (USA) Luca Delgrossi, Mercedes-Benz R&D N.A. (USA) Timo Kosch, BMW Group (Germany) Tadao Saito, University of Tokyo (Japan) Consumer Communicatons and Networking Madjid Merabti, Liverpool John Moores U. (UK) Mario Kolberg, University of Sterling (UK) Stan Moyer, Telcordia (USA) Design & Implementation Sean Moore, Avaya (USA) Salvatore Loreto, Ericsson Research (Finland) Integrated Circuits for Communications Charles Chien (USA) Zhiwei Xu, SST Communication Inc. (USA) Stephen Molloy, Qualcomm (USA) Network and Service Management Series George Pavlou, U. of Surrey (UK) Aiko Pras, U. of Twente (The Netherlands) Networking Testing Series Yingdar Lin, National Chiao Tung University (Taiwan) Erica Johnson, University of New Hampshire (USA) Tom McBeath, Spirent Communications Inc. (USA) Eduardo Joo, Empirix Inc. (USA) Topics in Optical Communications Hideo Kuwahara, Fujitsu Laboratories, Ltd. (Japan) Osman Gebizlioglu, Telcordia Technologies (USA) John Spencer, Optelian (USA) Vijay Jain, Verizon (USA) Topics in Radio Communications Joseph B. Evans, U. of Kansas (USA) Zoran Zvonar, MediaTek (USA) Standards Yoichi Maeda, NTT Adv. Tech. Corp. (Japan) Mostafa Hashem Sherif, AT&T (USA) Columns Book Reviews Andrzej Jajszczyk, AGH U. of Sci. & Tech. (Poland) History of Communications Mischa Schwartz, Columbia U. (USA) Regulatory and Policy Issues J. Scott Marcus, WIK (Germany) Jon M. Peha, Carnegie Mellon U. (USA) Technology Leaders' Forum Steve Weinstein (USA) Very Large Projects Ken Young, Telcordia Technologies (USA) Publications Staff Joseph Milizzo, Assistant Publisher Eric Levine, Associate Publisher Susan Lange, Online Production Manager Jennifer Porcello, Publications Specialist Catherine Kemelmacher, Associate Editor

MAGAZINE February 2011, Vol. 49, No. 2

www.comsoc.org/~ci SPECIAL SUPPLEMENT ADVANCES IN PASSIVE OPTICAL NETWORKS GUEST EDITORS: MAHMOUD DANESHMAND, CHONGGANG WANG, AND WEI WEI

S4 CONFERENCE PREVIEW OFC/NFOEC 2011: LEADING THE WAY IN OPTICAL COMMUNICATIONS LYNDSAY BASISTA

S8 CONFERENCE REPORT 36TH EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION FABIO NERI

S12 GUEST EDITORIAL S16 OPPORTUNITIES FOR NEXT-GENERATION OPTICAL ACCESS Next-generation optical access technologies and architectures are evaluated based on operators’ requirements. The study presented in this article compares different FTTH access network architectures. DIRK BREUER, FRANK GEILHARDT, RALF HÜLSERMANN, MARIO KIND, CHRISTOPH LANGE, THOMAS MONATH, AND ERIK WEIS

S25 COST AND ENERGY CONSUMPTION ANALYSIS OF ADVANCED WDM-PONS The authors compare several WDM-PON concepts, including hybrid WDM-PON with integrated per-wavelength multiple access, with regard to these parameters. They also show the impact and importance of generic next-generation bandwidth and reach requirements. KLAUS GROBE, MARKUS ROPPELT, ACHIM AUTENRIETH, JÖRG-PETER ELBERS, AND MICHAEL EISELT

S33 TOWARD ENERGY-EFFICIENT 1G-EPON AND 10G-EPON WITH SLEEP-AWARE MAC CONTROL AND SCHEDULING The authors briefly discuss the key features of 10G-EPON. Then, from the perspective of MAC-layer control and scheduling, they discuss challenges and possible solutions to put optical network units into low-power mode for energy saving. JINGJING ZHANG AND NIRWAN ANSARI

S39 MULTIRATE AND MULTI-QUALITY-OF-SERVICE PASSIVE OPTICAL NETWORK BASED ON

HYBRID WDM/OCDM SYSTEM

The authors present a new scheme to support multirate and multi-quality-of-service transmission in passive optical networks based on a hybrid wavelength-division multiplexing/optical code-division multiplexing scheme. The idea is to use multilength variable-weight optical orthogonal codes as signature sequences of a hybrid WDM/OCDM system. HAMZEH BEYRANVAND AND JAWAD A. SALEHI

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PASSIVE OPTICAL NETWORK MONITORING: CHALLENGES AND REQUIREMENTS The authors address the required features of PON monitoring techniques and review the major candidate technologies. They highlight some of the limitations of standard and adapted OTDR techniques as well as non-OTDR schemes. MOHAMMAD M. RAD, KERIM FOULI, HABIB A. FATHALLAH, LESLIE A. RUSCH, AND MARTIN MAIER

FOR INFORMATION ABOUT ADVERTISING CONTACT ERIC LEVINE ADVERTISING MANAGER 212-705-8920 [email protected] _______________

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(+=,9;0:,4,5;

Smartphone & Tablets Traffic Calls for Rethinking System Design Approaches By Gilles Garcia THE HUGE GROUNDSWELL in traffic on our optical transport networks (OTNs) is just the beginning. To date, only about 10% of the world’s population own Smartphones with web/data services. Service providers are competing aggressively for the largely untapped markets in China, India, and other parts of the globe, and performance is being touted as a key differentiator for attracting new customers. For example, in a recent announcement,1 AT&T revealed plans to invest between $18 billion and $19 billion—this year—to support even faster network performance for Apple iPhone, iPad, and other 3G-connected devices. With market share clearly dependent on building out OTN capacity, communication system designers are under pressure to speed the deployment of 100G ports and the evolution to 400G-capable networks. Many are turning to Xilinx Targeted Design Platforms for OTN to accelerate time to market and simultaneously take advantage of unparalleled power, bandwidth, and density optimization for large-scale integration of their systems. With the industry’s first optically compliant FPGA,2 Xilinx programmable platforms are helping industry leaders rapidly evolve their OTN capabilities. Cisco, in fact, recently named Xilinx its Supplier of the Year, for helping its design teams deliver next-generation networking solutions. Tellabs likewise recognized Xilinx this year, for helping 1 2

With bandwidth consumption expected to grow at alarming rates over the next few years, communication systems providers need to turn to programmable platforms to address the demand.

them grow and gain market share by enabling first-class products. The latest Xilinx OTN Targeted Design Platforms leverage devices that enable ultra-high bandwidth with the highest number of 11.2Gbps high-speed serial transceivers available on any FPGA—up to 24 for 11.2Gbps or 48 for 6.5Gbps of capacity. The Xilinx platforms will allow customers to accelerate their development for transponder, muxponder, or ODUFLEX applications for optical systems. The next-generation Xilinx devices (Xilinx 7 series FPGAs) will more than double that serial bandwidth to enable 400G line cards applications. This year, Xilinx also announced the industry’s first stacked silicon interconnect (SSI) technology for FPGAs, which is pushing capacity and bandwidth while driving down power requirements. By combining 3D packaging technologies and through-silicon vias (TSVs) with its 28nm 7 series FPGAs, Xilinx helps communications designers more than

double the reach of the largest single-die FPGAs (more than Moore’s Law) and extend capacity up to two-million logic cells. Xilinx also confirmed shipping in Q4 2010 of the industry’s only FPGA SERDES that meets 10G optical jitter performance for pairing with SFP+, XFP, and CFP optical modules. The superior jitter performance and signal integrity eliminates the cost of external signal conditioning and provides the margin needed to build robust highspeed interfaces. Be sure to stop by booth #2335 at OFC 2011 and see the next wave of advancements that Xilinx is bringing to communications systems. Xilinx will be demonstrating the newest OTN Targeted Design Platforms as well as other innovations that are accelerating the transition to 100/400G networks. Learn how Xilinx offerings can let you design today to meet the capacity requirements of the future. For more information on Xilinx Targeted Design Platforms, please visit www.xilinx.com.

AT&T press room, November 22, 2010, “AT&T Delivers Nation’s Fastest Mobile Broadband Network by Wide Margin” Xilinx news room, November 8, 2010, “Xilinx Virtex-6 HXT FPGAs Deliver Superior Transceiver Performance for Wired Optical Communications”

About the Author: Gilles Garcia is the Director of Product Marketing, Communication Business Unit, Xilinx Inc. (San Jose, Calif.). Contact him at _______________ [email protected]. © Copyright 2011 Xilinx, Inc. Xilinx, the Xilinx logo, Virtex, Spartan, ISE, and other designated brands included herein are trademarks of Xilinx in the United States and other countries. All other trademarks are the property of their respective owners.

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CONFERENCE PREVIEW OFC/NFOEC 2011: LEADING THE WAY IN OPTICAL COMMUNICATIONS BY LYNDSAY BASISTA Once again, optical communications and networking professionals from around the world will come together for an intense week of networking, high-quality science, and the most comprehensive exhibit in the industry at the Optical Fiber Communication Conference and Exposition (OFC) and the National Fiber Optic Engineers Conference (NFOEC). This year’s conference will feature hundreds of peer-reviewed technical and invited presentations, a rump session focusing on “green” networking, a special symposium on computer components and architectures, an exhibit hall with more than 500 leading optical communications companies and so much more. Areas that will be highlighted include: Datacom/Data Centers, FTTx/In-home, Next Generation Data Transfer Technology, Photonic Integration and Wireless Backhaul. OFC/NFOEC will be held at the Los Angeles Convention Center in Los Angeles, Calif. from March 6 – 10 with the exposition taking place March 8 – 10.

PLENARY SESSION This year’s plenary speakers are leaders at the forefront of the optical communications industry. As always, OFC/NFOEC draws speakers who are industry veterans and their wide range of expertise is certain to be a main attraction at this year’s OFC/NFOEC. The event will take place on Tuesday, March 8 from 8 – 11 a.m. Olivier Baujard, Chief Technology Officer at Deutsche Telekom has had a career spanning all facets of the telecommunications industry. From his time at France Telecom where he held engineering and managerial roles to his 20-year tenure at Alcatel-Lucent, France where he rose to the level of chief executive officer and chairman, Baujard has been a leader in the ever-changing telecommunications industry. In his current position at Deutsche Telekom, Baujard is responsible for the group-wide engineering, deployment and operation of fixed, mobile and carrier infrastructures. During his plenary talk, Baujard will discuss the future data and media-centric world with a particular emphasis on the challenges it presents for network operators. Additionally, he will cover network transformation and strategy and practical examples of how to enable efficient broadband. Baujard will also provide insights about Deutsche Telekom and their vision for the future of wireless services. Providing an insider’s perspective on the advances and developments that optical technologies have on supercomputing is Alan Gara, IBM Fellow and Blue Gene Chief Architect. Gara’s talk will discuss the challenges of reaching computing at the exaflop level with a special emphasis on areas where traditional communication solutions will not suffice. Gara has been leading high performance computing architecture and design efforts at IBM Research since 1999. Before then, Gara worked on the Superconductor supercollider (SSC) in Texas and at the Large Hadron Collider (LHC) at CERN. He has been the recipient of many prestigious awards for his supercomputing efforts including two Gordon Bell awards. With a career spanning more than 30 years in the telecommunications industry, Kristin Rinne, Senior Vice President – Architecture & Planning at AT&T, will share with attendees her outlook on the explosive growth of mobile data and how that growth impacts optical networks including cell site back-

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haul. Rinne is responsible for the IT and Network architecture and planning for AT&T, including setting the direction for the Network, BSS/OSS Systems, Services, etc. She is also responsible for the IPTV and the wireless network infrastructure and device technology vendor selection and first office implementation. Prior to joining AT&T, Rinne served as Cingular’s chief technology officer and before that was vice president–Technology Strategy at SBC Wireless and managing director–Operations at Southwestern Bell Mobile Systems. The plenary session will be held on Tuesday, March 8 from 8 – 11 a.m.

RUMP SESSION Back for its third year is the always popular Rump Session, an audience-driven discussion designed to be as interactive and dynamic as possible. This year’s Rump Session will be devoted to the question: “Is green networking revolutionary?” Organizers are looking for attendees to discuss whether a more energy-efficient network is crucial to continued growth of the Internet or if “green” is merely today’s buzzword for something quite familiar to us in the past, whether energy bottlenecks will constrain network growth if more attention is not paid to energy efficiency, and whether consumers and carriers will pay more to go “green,” and whether “green” networking will reduce costs in the long run. Any audience member is permitted to participate in the discussion and can use slides to further demonstrate points (no more than two can be accepted). The Rump Session will take place Tuesday, March 8 from 7:30 – 9:30 p.m.

EXHIBIT HALL The OFC/NFOEC exhibit hall attracts some of the biggest players in the optical communications industry from fiber equipment and components manufacturers to systems and cable vendors, participating companies include industry heavyweights like Juniper Networks, JDSU, Huawei, Finisar, Ciena and Nokia Seimens. The exhibit hall will be the place to see the latest in product demonstrations and innovation while also providing an opportunity for networking with industry leaders. The exhibit hall is also home to a number of programming events and activities. New this year, EXPO Theater II will have an optical networking focus and will feature events such as the Ethernet Alliance Program (panel discussion on the future of high-speed Ethernet and new storage facilities for efficiency and flexibility), the Green Touch Panel Presentation (panel discussion on when the energy crunch will affect optical networks), and the Optical Internetworking Forum (panel discussions on market requirements for the next generation optical network, considering 400G vs.1 Terabit speeds; and building blocks for high-speed, on-demand services).

THE OPTICAL BUSINESS FORUM – TUESDAY, MARCH 8 Optical technologies have become integral to the solutions needed to ensure the speed – and capacity – of transactions can keep pace with the needs of customers in the business world. The Optical Business Forum will discuss the latest advances in optical business services with sessions including: (Continued on page S6)

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CONFERENCE PREVIEW (Continued from page S4) •Who’s Buying Optical Bandwidth Services? •The Economics & Business Case for Connecting Data Centers •Carrier Ethernet Exchanges Additional information can be found online: http://www.ofcnfoec.org/OBF

SERVICE PROVIDER SUMMIT – WEDNESDAY, MARCH 9

INVITED SPEAKERS

Also in the exhibit hall is the perennial favorite Service Provider Summit. The Service Provider Summit is geared toward CTOs, network architects, network designers and technologists within the service provider and carrier sector. The program will include a keynote presentation, exhibit time and networking time. Keynote Presentation: The Financial Industry’s Race to Zero Latency and Terabit Networking – Andrew Bach, Senior Vice President and Global Head of Network Services, NYSE Euronext Panels: •Evolution to Higher Speed •What’s Going on in Wireless? Additional information can be found online: http://www.ofcnfoec.org/Service_Provider_Summit

OFC/NFOEC invited speakers are chosen through a highly selective nominations process to keep attendees at the forefront of optical communications. This year’s exciting lineup of speakers will cover various topics in 14 categories, from Optical Network Applications and Services to Transmission Subsystems and Network Elements. •Regulation Environments around the World: Impacts on Deployments, Fabrice Bourgart, France Telecom, France. •Google Optical Network Deployment, Vijay Vusirikala, Google, USA. •Energy-Efficient Optical Access Network Technologies, Junichi Kani, NTT Access Service Systems Labs, Japan. •Cloud Computing over Telecom Network, Dominique Verchere, Alcatel-Lucent Bell Labs France, France. •Scaling Networks in Large Data Centers, Donn Lee, Facebook, USA. •Optical Networking Trends and Evolution, Christoph Glingener, ADVA Optical Networking, Germany. A full list of invited speakers is available online: http://www.ofcnfoec.org/Invited_Speakers

MARKET WATCH – TUESDAY, MARCH 8 – THURSDAY, MARCH 10 This three-day series of panel sessions engages the applications and business communities in the field of optical communications. Presentations and panel discussions feature esteemed guest speakers from industry, research and the investment communities. Tuesday Panels: •State of the Optical Industry •Implications of Converged Wireline Wireless for Network Evolution Wednesday Panel: •100G Ecosystem: Enabling Technology and Economics Thursday Panels: •Data Center: Traffic and Technology Drivers •What’s Next for Optical Networking More information can be found online: ____________ http://www.ofcnfoec.org/Market_Watch

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SHORT COURSES Short Courses cover a broad range of topic areas at a variety of educational levels. The courses are taught by highly regarded industry experts on subjects such as 40 Gb/s transmission systems, optical transmission systems, photonic integrated circuits, and ROADM technologies. New topics for 2011 include computercom interconnects and data center networking. More information on the Web: http://www.ofcnfoec. org/Short_Courses/

WORKSHOPS Workshops and panel discussions will take place throughout the conference and will cover all topical areas of OFC/NFOEC. Some topics include: •Beyond 100G, Options and Implications for Today’s Networks TJ Xia, Verizon USA; Milorad Cvijetic, NEC and Frank Chang, Vitesse. •FTTH Around the World: Today and Tomorrow Shoichi Hanatani, Hitachi. •FTTX and Technical Challenges of Emerging Applications: How Do We Keep Up with the Pace of Digital Evolution David Li, Ligents Photonics. A full list of workshops and panel discussions is available online at: http://www.ofcnfoec.org/Workshops_ and_Panels

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Innovations Needed? Why Whykeep keepher herwaiting? waiting?

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ECOC 2010 CONFERENCE REPORT

36TH EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION BY

FABIO NERI, POLITECNICO DI TORINO

The annual European Conference on Optical Communication (ECOC) is the largest conference on optical communication in Europe, and one of the largest and most prestigious events in this field worldwide. ECOC travels from one European country to another each year and this year has visited Turin, Italy, for the first time, after the two previous successful ECOCs, 2008 in Brussels and 2009 in Vienna. As a not-for-profit conference, ECOC focuses on the dissemination of new research results, the education of engineering and business leaders, and the exposition of cutting-edge optical fiber communication and networking products in the associated exhibition. ECOC brings together professionals in several fields related to optical communications, covering the areas of fiber design, opto-electronic devices, optical transmission systems, optical transport networks, and access technologies, all the way to future optical routing architectures and quantum information applications. Most of the major international telecommunication service providers and optical network system vendors participate and present their most recent developments at ECOC each year. ECOC 2010 was held from 19 to 23 September in Turin, Italy, at the Lingotto Conference and Exhibition Center, former location of Fiat’ s first major car factory, built between 1917 and 1920. Lingotto houses today a shopping center, a hotel, an art gallery, a concert hall and a conference center: a large modern structure designed especially for conventions. The city of Turin is a major business and cultural center in northern Italy. Founded by the Romans over 2000 years ago, in 1861, it became the first capital of Italy, playing a leading role in the nation’s history as a city of many vocations: political, social, and cultural. Although it owes its recent development mainly to industry, today it offers a variety of attractions: Roman ruins, Baroque monuments, urban landscapes, world-class museums — like the Egyptian Museum, featuring the second most important collection after that of Cairo — a vibrant cultural life, and several opportunities for sport and recreation. The region is also renowned for its varied and refined cuisine, and the famous wines from the surrounding area. For what concerns the scientific history of the town, important contributions to the early developments of fiber optic communications were made by the CSELT laboratories of Telecom Italia, located in Turin. September 2010 was indeed the 33rd anniversary

Delegates at ECOC 2010.

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The ECOC 2010 Technical Program co-Chairmen: P. Poggiolini, M. Schiano, and A. Galtarossa (left to right).

Plenary session at the Lingotto Auditorium, designed by Renzo Piano.

of an important event in the history of optical communications: in September 1977 the first optical communication cable, called COS 2, was laid between two urban exchanges of SIP (now Telecom Italia). ECOC 2010 was the 36th conference edition, and confirmed ECOC’s reputation and attractiveness as one of the world’s major forums for discussion of the most recent advances in research, development, and industrial applications of optical communication technologies and networks. The general co-Chairmen of ECOC 2010 were Pierluigi Franco (PGT Photonics), Fabio Neri (Politecnico di Torino), and Giancarlo Prati (Scuola Superiore Sant’Anna and Centro Nazionale Interuniversitario per le Telecomunicazioni — CNIT). The conference was organized by the Stilema company, based in Turin. ECOC 2010 was attended by 1111 delegates from all over the world; the countries with the largest representation were Japan, the United States, Germany, and Italy. As in the ECOC tradition, a major exhibition was collocated with the conference, offering a showcase for the most recent advances in optical communications products. Three hundred companies worldwide participated as exhibitors, and the countries with the largest representation among exhibitors were China and the United States; 3775 exhibition visitors were registered in addition to conference delegates. The conference was organized by Nexus Business Media, United Kingdom. (Continued on page S10)

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ECOC 2010 CONFERENCE REPORT (Continued fromwas pagesponsored S8) ECOC 2010 by Telecom Italia, Cisco, Ericsson, Istituto Superiore Mario Boella, and ZTE, and by the local authorities and agencies Regione Piemonte, Camera di Commercio Artigianato e Agricoltura di Torino, Unione Industriale Torino, and Fondazione CRT. A rich technical program was organized by technical program co-Chairmen Andrea Galtarossa (Università di Padova), Pierluigi Poggiolini (Politecnico di Torino), and Marco Schiano (Telecom Italia). The conference program started on Sunday with 11 well attended (over 650 delegate badges were collected on Sunday) half-day workshops. The opening session was held in the Lingotto Auditorium, and featured three world-renowned plenary speakers from industry and academia: Menahem Kaplan (former CTO of Alcatel-Lucent Optics), with a talk on “Technology Opportunities Beyond and Besides 100G,” Masataka Nagazawa (Tohoku University, Japan), with a talk on “Giant Leaps in Optical Communication Technologies Towards 2030 and Beyond,” and John Bowers (University of California atSanta Barbara), with a talk on “Challenges in Silicon as a Photonic Platform.” The bulk of the conference program was based on contributed technical papers, carefully selected for oral or poster presentation by an outstanding technical program committee, comprising around 100 well-known experts of the field, and organized in six subcommittees: “Fibers, Fiber Devices and Amplifiers,” “Waveguides and Optoelectronic Devices,” “Subsystems and Network Elements for Optical Networks,” “Transmission Systems,” “Backbone and Core Networks,” and

Gala dinner at La Venaria Reale royal castle.

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Welcome reception, “Taste of Piemonte.” “Access Networks and LANs.” The 245 oral and 131 poster paper presentations were complemented by 38 invited talks from renowned experts, six tutorial presentations, and seven symposia focused on hot topics, organized in 71 sessions running in seven parallel tracks for the four conference days. The poster session on Wednesday afternoon was very popular, with intense informal discussions among authors and other conference delegates. The most recent research achievements and breakthroughs in the field of optical communications were presented in post-deadline paper sessions at the end of the conference. The European Physical Society and CLEO Europe-EQEC organized within ECOC 2010 a special CLEO Focus Meeting on New Frontiers in Photonics, aimed at bridging the gap between basic science and optical telecommunications applications. The CLEO Focus Meeting covered five sessions in the ECOC program. Seven hundred ninety-three regular papers and 66 postdeadline papers were submitted to ECOC 2010. The acceptance ratio was 51 percent for regular papers (33 percent for oral presentations and 18 percent for posters), and 27 percent for post-deadline papers. Accepted ECOC 2010 papers are now available on IEEE Xplore, thanks to the technical sponsorship of the IEEE Photonics Society. The ECOC 2010 conference organization has enriched the technical program with a wide range of social events and additional services. A get-together cocktail was offered on Sunday evening, and a welcome reception was held at the Lingotto Conference Center on Monday evening, with around 1000 participants. The gala dinner was organized at the La Venaria Reale royal castle, part of the UNESCO World Heritage, and was a memorable event for over 500 participants. In the closing session, the token was passed to the organizers of ECOC 2012 in Geneva, who offered chocolate to participants, representing the worldwide reputation of Switzerland in chocolate making. ECOC 2010 confirmed the ECOC tradition of high-quality technical contributions, and very active and interactive participation of the lively research community on optical communications and technologies. The CLEO Focus Meeting, the ECOC conference, and the ECOC exhibition together provided an exciting inter- and multidisciplinary forum for people from basic research, R&D, industry, and telecom operators interested in optical communications. The rich social program and conference services contributed to making ECOC 2010 a memorable edition. More details on ECOC 2010 are available at http://www.ecoc2010.org.

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«Excellent wireless site solutions for LTE» FTTA – Fiber To The Antenna • ODC® – Leading standard solution for remote radio systems, plug & play PTTA – Power To The Antenna • Outdoor power cable system to remote radio heads LISCA – Antenna Jumper Cables • Low PIM optimized Lightning Protection • Low PIM optimized designs • 10 kA protection for telco lines • Up to 100 kA protection for RF line PIM Test Kits – Field Solutions • Everything needed for on-site testing and certification USA and Canada: Toll free 1866 HUBER SUHNER(1-866-482-3778) Fax 1-802-878-9880 HUBER+SUHNER AG 9100 Herisau Switzerland [email protected] _____________

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GUEST EDITORIAL

ADVANCES IN PASSIVE OPTICAL NETWORKS

Mahmoud Daneshmand

Chonggang Wang

A

s an ultimate broadband access solution for future Internet, the passive optical network (PON) brings many advantages such as cost effectiveness, energy savings, service transparency, and signal security over other last-/first-mile technologies. Over the past several years, we have witnessed significant development and deployment of time-division multiple access (TDMA) PONs such as IEEE 802.3ah Ethernet PONs (EPONs) and ITUT G.984 Gigabit PONs (GPONs) to provide high-quality triple-play services for residential users. However, future Internet applications, apart from triple-play service (e.g., peer-to-peer [P2P] social networking, online video sharing, grid computing, and mobile Internet), along with their unique traffic characteristics and huge bandwidth requirements, pose big challenges for current PON design and migration, which in turn are driving legacy TDMA PONs toward ultra-high-speed flexible next-generation PONs such as wavelength-division multiplexed (WDM) PONs and optical orthogonal frequency-division multiplexed (OFDM) PONs, and/or a hybrid WDM/OFDM/ TDM PON. This special issue features recent and emerging advances in PONs. Of the large number of submitted papers, five were selected for this issue . The selected articles cover topics including next-generation PON architecture, energy-efficient PONs, layer 2 medium access control (L2 MAC), quality of service (QoS) provisioning in future PONs, and PON monitoring techniques. The first article, “Opportunities for Next Generation Optical Access,” coauthored by Dirk Breuer, Frank Geilhardt, Ralf Hülsermann, Mario Kind, Christoph Lange, Thomas Monath, and Erik Weis, discusses the impact of the new business models on network architecture based on the comparison of different optical access network variants. It also pro-

1

Please note that several more papers were accepted as the second part of the special issue and will be published in the September 2011 issue of IEEE Communications Magazine.

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Wei Wei

vides perspective on access node consolidation for network operators. One of the PON’s advantages is the potential to provide high energy efficiency toward future green communications. The second article, “Cost and Energy Consumption Analysis of Advanced WDM-PONs” contributed by Klaus Grobe, Markus Roppelt, Achim Autenrieth, Jörg-Peter Elbers, and Michael Eiselt, focuses on the analysis of cost and energy-consumptions of future advanced WDM-PON options. The authors conclude that it is essential to carefully clarify the requirements for next-generation access with regard to per-PON client count and maximum reach. In particular, if client count does not exceed ~320, and a passive filter-based optical distribution network (ODN) is accepted, the most efficient solution, with regard to both cost and power consumption, is a simple WDM-PON. The article “Toward Energy-Efficient 1G-EPON and 10G-EPON with SleepAware MAC Control and Scheduling,” co-authored by Jingjing Zhang and Nirwan Ansari, presents L2 techniques, proposing sleep-aware MAC control and scheduling approaches for EPON. Two sleep-mode control and sleep-aware scheduling schemes are analyzed: sleep for over one DBA cycle and sleep within one DBA cycle. In addition to reducing energy consumption, multirate and multi-QoS provision is a critical feature next-generation PONs shall possess naturally to cater for existing and emerging Internet applications. The article titled “Multirate and Multi-Quality-of-Service Passive Optical Network Based on Hybrid WDM/OCDM System” by Hamzeh Beyranvand and Jawad A. Salehi proposes a new scheme to guarantee multi-QoS in WDM/OCDM system. The basic idea is to use multilength variable-weight optical orthogonal codes (MLVWOOC) as the signature sequence of an OCDM system. The code weight and code length of MLVWOOC are designed based on the characteristics of the requested classes of services. The last article, “Passive Optical Network Monitoring: (Continued on page S14)

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GUEST EDITORIAL (Continued from page S12)

Challenges and Requirements,” co-authored by Mohammad M. Rad, Kerim Fouli, Habib A. Fathallah, Leslie A. Rusch, and Martin Maier, touches on a different problem. In addition to the discussion of challenges and requirements for PON monitoring, it presents a comprehensive review of techniques for in-service monitoring PONs to detect and localize faults. The authors recommend the hybrid techniques as promising solutions for delivering the maintenance and protection functionalities required by current and next-generation PONs. We would like to take this opportunity to thank our reviewers for their effort in reviewing the manuscripts. We also thank the Editor-in-Chief, Dr. Steve Gorshe, for his supportive guidance during the entire process.

BIOGRAPHIES ____________ is a Distinguished Member MAHMOUD DANESHMAND ([email protected]) of Technical Staff, AT&T Labs Research; executive director of the University Collaborations Program and assistant chief scientist of AT&T Labs; adjunct professor of computer science at the Stevens Institute of Technology; and adjunct professor of electrical engineering at Sharif University of Technology. He has more than 35 years of teaching, research and publications, and management experience in academia and industry, including Bell Laboratories, AT&T Labs, the University of California at Berkeley, the University of Texas at Austin, Tehran University, Sharif University of Technology, National University of Iran, New York University, and Stevens Institute of Technolo-

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gy. He has published more than 70 journal/conference papers and book chapters, co-authored two books, given several keynote talks, and served as general chair and TPC chair of many IEEE conferences. His current areas of teaching and research include artificial intelligence, knowledge discovery and data mining, complex network analysis, sensor network and RFID system reliability and performance, and mining of sensor and RFID data. He has Ph.D. and M.A. degrees in statistics from the University of California, Berkeley, and M.S. and B.S. degrees in mathematics from the University of Tehran. CHONGGANG WANG ([email protected]) __________ is a senior staff engineer in InterDigital Communications. Before joining InterDigital Communications, he conducted research with NEC Laboratories America, AT&T Labs Research, the University of Arkansas, and Hong Kong University of Science and Technology. His research interests include future Internet, machine-to-machine (M2M) communications, and wireless networks. He has published more than 80 journal/conference articles and book chapters. He is on the editorial boards of IEEE Communications Magazine, IEEE Network, ACM/Springer Wireless Networks, and Wiley Wireless Communications and Mobile Computing. He has served as a TPC member for numerous IEEE conferences including ICNP, INFOCOM, GLOBECOM, ICC, and WCNC. He received his Ph.D. in computer science from Beijing University of Posts and Telecommunications in 2002. WEI WEI [SM] ([email protected]) ___________ is a senior engineer at Ciena Corporation. Before joining Ciena, he conducted research with NEC Laboratories America and the State University of New York at Buffalo. His research interests include cognitive optical networks, network virtualization, and future Internet. He has published more than 60 journal/conference articles and book chapters. He also has rich engineering experiences in developing and designing broadband optical networks and IP networks. He is the holder of three patents with five others pending. He has served as a TPC member for several IEEE conferences including GLOBECOM and ICC. He received his Ph.D. degree in electrical engineering from Shanghai Jiao Tong University.

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ADVANCES IN PASSIVE OPTICAL NETWORKS

Opportunities for Next-Generation Optical Access Dirk Breuer, Frank Geilhardt, Ralf Hülsermann, Mario Kind, Christoph Lange, Thomas Monath, and Erik Weis, Deutsche Telekom Laboratories

ABSTRACT Next-generation optical access technologies and architectures are evaluated based on operators’ requirements. The study presented in this article compares different FTTH access network architectures. Additionally, the impact of new business models on network architectures is discussed.

MOTIVATION It is expected that in the near future an end user will require much more guaranteed bandwidth than is available today [1]. There is a common understanding that fiber to the home (FTTH) will overcome the bandwidth limitations of today’s copper-based and hybrid fiber access solutions (e.g., fiber to the cabinet [FTTCab]). FTTH is seen as the ultimate and most futureproof access solution. In consequence, this means building a completely new access network, thus requiring enormous investment and potentially allowing new business models. In the long run this will enable next-generation optical access (NGOA) networks where the access network is not limited to the first mile but will potentially further extend beyond today’s central offices (COs). The target function when optimizing the structure of such a new network is rather simple: satisfy all the needs of the customers along with minimized total costs of ownership (TCO) for building and operation of the whole network. When looking at a cost-optimal structure of the access/aggregation network, its structure can be subdivided into different building blocks, and the cost of the majority of the building blocks depends significantly on the number of access sites. This is shown in Fig. 1. In this model the access site is the demarcation point between the access network and the aggregation network providing active network elements, which terminate the access lines, aggregate the traffic, and forward the aggregated traffic via the aggregation network toward the core network. Nevertheless, access and aggregation networks can merge seamlessly when making use of appropriate optical-fiberbased network architectures and related systems. Considering the different building blocks, the following interdependencies can be seen.

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The costs of the first mile and in-house cabling, used for connecting the customer premises, are mostly driven by the number of customer connections and the customer density in a given area, and are independent of the number of access sites. The cost of the feeder links, which connect the first mile with the access sites, are mostly driven by the length of the feeder links, first due to the building and material costs of the cables, and second due to rising costs of the used access network systems when increasing the reach requirements. Since the length of the feeder links will decrease with an increasing number of access sites, the costs of this link are inversely proportionally related to the number of access sites. The cost of building and operating the access sites scales with the number of sites. When decreasing the number of access sites, the mean number of customers per site will increase, and in consequence the size of the traffic switches inside the access sites can be increased. The cost for maintaining the network equipment installed in the access sites is also related to the number of access sites: maintaining centralized equipment installed in a small number of access sites will cause smaller traveling times and a smaller number of required maintenance personal compared to distributed equipment installed in a higher number of access sites. The costs of the aggregation links will increase with an increasing number of access nodes. In our model the aggregation link includes the egress interfaces of the switches inside the access nodes, the transmission systems (typically wavelength-division multiplexing [WDM] systems), and the ingress interfaces of the core network equipment. The mean number of customers connected to an access site increases with a decreasing number of access sites, and the number of customers per switch will also increase. A higher number of customers per switch will result in a higher amount of aggregated traffic at the egress of the switch; therefore, the required capacity of the egress interfaces also increases. The cost of these four building blocks contributes significantly to the total cost of the access/aggregation network. When analyzing the sum of the three cost types, the cost function has a minimum defining the cost-optimal number of access nodes. The characteristics of the cost

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F

These cost considerations affect

PoP Aggregation network

a number of players Total costs

Access network

Access site

Costs

Aggregation links Access site

Feeder link costs

who maintain an Site costs

active interest in future access

First mile costs

networks. Even under competition the deployment and

Feeder links

operation of First mile Optical distribution network/ customer premises

Aggregation link costs Number of access sites

broadband networks is an attractive business area for a still increasing

Figure 1. Principal building blocks of access/aggregation networks and corresponding cost structure as a function of the number of access sites. function of each network segment are strongly related to the deployed technology in the respective network segment (e.g., copper lines vs. FTTx in the access network). Therefore, it is expected that the cost-optimal number of access nodes for NGOA will differ from the cost optimum in copper-based access networks. Particular attention should be paid to the costs of the feeder link section since only the feeder link cost decreases with increasing number of access sites. In copper-based access networks the cost of the feeder link section is strongly related to the pure material cost of the cables, which depends on the length and the cross-sectional area of the copper wires. The maximum transmission distance is limited by the copper line loop resistance and can only be increased by increasing the cross-sectional area of the copper wires or introducing intermediate repeaters, which both would drive feeder link costs. In optical access networks the situation is different: Due to the superior transmission characteristics of optical fibers — high transmission bandwidth and low loss — the interdependency between feeder cable length and feeder section costs is much more relaxed. Furthermore, point-to-multipoint optical access network architectures provide multiplexing of several subscriber lines, which decreases the number of required feeder fibers significantly compared to a copper-like point-to-point architecture. Therefore, we expect that the cost-optimal number of access sites in optical access networks will be below the number of access sites in today’s copper-based access networks. These cost considerations affect a number of players who maintain an active interest in future access networks. Even under competition, the deployment and operation of broadband networks is an attractive business area for a still increasing number of players. This includes mobile as well as fixed operators, but also utility companies like energy providers; even construction companies are entering this business environment. This article gives an overview of today’s FTTH approaches and the related economics, and an outlook toward network consolidation

number of players.

evolution and the enabling optical access network technologies. In addition, the impact of new business models on network architecture and the requirements resulting from node consolidation concepts are qualitatively discussed.

TODAY’S FTTH APPROACH FIBER RICH VS. SHARED APPROACH FTTH networks can be deployed using different architectures as shown in Fig. 2. In a point-topoint (PtP) architecture all subscribers are connected to an access node (e.g., CO) via dedicated fibers. Today’s PtP deployments are mainly based on Ethernet technology using Ethernet switches in the access node with a high port density. The network termination at the subscriber site is realized with media converters (e.g., 100Base-TX ‹ 100Base-BX) or mini-switches. The PtP architecture with its dedicated fiber connections requires a very high number of fibers in the whole access network, which causes high costs for fiber rollout and handling. In addition, each connection requires two interfaces, which cause high footprint and power consumption. In order to reduce the high number of fibers in the access network, point-to-multipoint (PtMP) architectures can be used. A PtMP architecture offers one or more additional aggregation layers between the subscriber location and CO. In general, two PtMP architectures can be distinguished: the active optical network (AON) and passive optical network (PON). The AON is determined by an active aggregation element (e.g., Ethernet switch) in the first mile. Figure 2 shows two AON variations. In one AON concept an Ethernet switch is located at the street cabinet (Fig. 2a), whereas in the second variant an Ethernet switch is used at the building location (Fig. 2b). On one hand the AON allows a reduction of the fiber count in the access network compared to a PtP solution, but on the other hand it is not able to decrease the number of required interfaces, so it is virtually impossible to reduce the footprint and power consumption.

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This analysis assumes

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PoP

Home/building

CO

Cab

a zero touch

Metro access node

deployment. This means that the fiber

Inhouse

infrastructure and the system

1. PtP

ONT ONT ONT

2a. AON

ONT ONT ONT

2b. AON

ONT ONT ONT

3. PON

ONT ONT ONT

equipment of the first mile are deployed at the beginning for final

First mile network

Feeder network

1

1 or 2 Not considered in the economic analysis

demand but the ONTs and the system equipment of CO

Aggr. network

1

1 or 2

location are considered demandorientated. 4. Optical access and node consolidation

ONT ONT ONT

1 OLT Power splitter

e.g. GPON

Splitter/switch/...

OLT/switch / ...

Figure 2. FTTH architectures and reference points. In contrast to an AON, PON aggregation is based on passive components such as optical power splitters or WDM (de)multiplexers. Today, typically 32–64 subscribers are connected to one PON port at the optical line termination (OLT). This means that a PON architecture enables fiber reduction as well as optimization of the footprint and power consumption compared to a PtP architecture.

AN OPERATOR’S VIEW ON ECONOMICS This analysis is based on the FTTH architectures depicted in Fig. 2. The scenarios have been modeled based on commercially available technology from leading system vendors. The PtP and AON scenarios are predicted on switched Ethernet technology. The AON switches in the first mile are connected to an Ethernet switch at the CO via optical gigabit Ethernet links (1GbE or 10GbE). The Ethernet optical network termination (E-ONT) at the subscriber site is linked to an AON switch via single-fiber Ethernet lines (100Base-BX, 1000Base-BX). Two transmission data rates have been considered for the PtP and AON scenarios, 100 Mb/s and 1 Gb/s. The PON scenario has been modeled with a G-PON system and a splitting ratio of 1:32, enabling a data rate of 2.5 Gb/s (downstream) and 1.25 Gb/s (upstream). The results refer to a dense urban service area with one CO, 100 street cabinets, 2000 buildings, and 16,000 subscribers. This service area is a brownfield area with a high number of empty ducts that can be used for fiber rollout. This analysis assumes a zero touch deployment. This means that the fiber infrastructure and the system equipment of the first mile are

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deployed at the beginning for final demand but the ONTs and the system equipment of CO location are considered demand-orientated. All scenarios allow a guaranteed downstream data rate of 100 Mb/s. This means that maximum 25 subscribers can be connected to one G-PON. A peak data rate of 1000 Mb/s at the User Network Interface (UNI) of the ONT is supported by the G-PON and PtP/AON solutions with a transmission data rate of 1 Gb/s. The PtP/AON scenarios with a transmission data rate of 100 Mb/s allow a peak data rate of 100 Mb/s. The techno-economical analysis considers the cost of the active system technology and the fiber infrastructure including installation. The fiber infrastructure takes into account the civil works (digging), fiber cables, optical passive splitters, optical distribution frame (ODF) at the CO, outdoor cabinets, and power for the active technology in the field. The system technology has been modeled on the basis of the price information provided by the vendors. Table 1 shows, as an example, the relative price information for the G-PON and PtP/AON solutions with a transmission data rate of 1 Gb/s. The difference between prices for the same network element from different vendors (e.g., pluggable 10GbE transceiver) can be explained by various business strategies. Figure 3a shows the total cost per line over the number of subscribers for the FTTH architectures described in Fig. 2. The results are normalized to the total cost per line of the G-PON solution at the end of the rollout (16,000 subscribers). The chart shows that the G-PON results in the lowest total cost per line independent of the number of connected subscribers. Especially in

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Network element

Description

Relative price

GPON

F

The fiber infrastructure takes into

ONT

Data only

CO OLT

1.00

account the civil works, fiber cables,

GPON OLT with 16 PON card slots

—

Basic costs

incl. chassis, fan, power supply, switch fabric

78.67

Optics uplink

10GBASE-LR X2 module

11.00

tion frame (ODF) at

Line card uplink

2 × 10GbE

6.91

the CO, the outdoor

PON card

4 × G-PON ports incl. class B optics

80.00

ONT

Data only

0.87

CO switch

Ethernet switch with 8 Line card slots

—

Basic costs

Incl. chassis, fan, power supply, switch fabric

179.66

Optics uplink

10GBASE-LR X2 Module

20.26

Line card uplink

6 × 10GbE

126.57

Optics downlink

1000BASE-BX

6.58

Line card downlink

48 × 1000BASE-X

83.53

optical passive splitters, optical distribu-

cabinets and the power for the active

PtP with GbE interface

technology in the field. The system technology has been modeled on the basis of the price information provided by the vendors.

AON with Cab switch and GbE interface PtP ONT

Data only

0.87

CO switch

Ethernet switch with 8 line card slots

—

Basic costs

incl. chassis, fan, power supply, switch fabric

151.89

Optics (up and down)

10GBASE-LR X2 Module

20.26

Line card

4 × 10GbE

101.28

Ethernet switch with 5 Line card slots

—

Basic costs

incl. chassis, fan, power supply, switch fabric

130.29

Line card downlink

48 × 1000BASE-X

83.53

Optics downlink

1000BASE-BX

6.58

Optics uplink

10GBASE-LR X2 module

20.26

Cab switch

AON with basement switch and GbE interface PtP ONT

Data only

0.87

CO switch

Ethernet switch with 11 line card slots

—

Basic costs

incl. chassis, fan, power supply, switch fabric

313.93

Optics uplink

10GBASE-LR X2 Module

20.26

Line card uplink

4 × 10GbE

101.28

Optics downlink

1000BASE-BX

6.58

Line card downlink

48 × 1000BASE-X

126.59

Ethernet switch

—

Basic costs

12-port 1000BASEs-X Ethernet switch

40.48

Optics (up & down)

1000BASE-BX

6.58

Basement switch

Table 1. Relative price information.

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Total costs per line (equipment + infrastructure)

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Power consumption of FTTH variants in a dense urban service area (without ONT)

6

160 140

5

Building (basement) Cabinet (air conditioning) Cabinet CO

120 4 P/kW

100

3

80 60

2

40 20

1 0 1 0 0

2000

4000

6000

8000 10,000 12,000 14,000 16,000 Subscribers

AON with cab switch and GbE interface AON with cab switch and 100BT interface AON with basement switch and GbE interface PtP with 100BT interface PtP with GbE interface G-PON

2

3

4

5

6

1. PtP with GbE interface (UNI) 2. PtP with 100BT interface 3. AON with cab switch and GbE interface 4. AON with cab switch and 100BT interface 5. AON with basement switch and GbE interface 6. G-PON with GbE interface

Figure 3. a) Total costs per line for different FTTH architectures; b) energy consumption of different FTTH variants.

the economically sensitive initial deployment period with a low number of subscribers, the total cost per line decreases very fast due to the high level of sharing of the PON architecture. Though the system costs of the PtP solutions are lower for small subscriber numbers (less than 250–750 users per service area), the total cost are higher due to the infrastructure effort (fibers). For 100 percent coverage the total cost per line of the AON scenario with an Ethernet switch at the street cabinet (100 Mb/s transmission rate) is about 1.5 times more expensive than the G-PON solution. The total cost per line of the AON scenario with an Ethernet switch at the street cabinet and a transmission rate of 1 Gb/s is almost 2.3 times more expensive than the G-PON variant. The worst result has been calculated for the AON scenario with Ethernet switch at the building location (Fig. 2b). For 100 percent coverage the total costs per line are about 2.7 times more costly than the G-PON solution. This is mainly caused by the high cost of the building switch that has to fulfill network operator requirements. The cost of this switch cannot be compared with the cost of a simple LAN switch. At the beginning of the FTTH deployment with a low number of subscribers the PtP solution has a lower total cost per line than the AON variant because the AON equipment in the field causes very high initial investment due to zero touch rollout. The optical interfaces of the PtP solution have been considered demand-orientated, but the equipment of the AON has been deployed at the beginning for 100 percent coverage. Another important aspect within the comparison of different FTTH architectures is the energy consumption, since over the lifetime of a deployed technology it is a major contribution to the operational expenditures and also has a direct environmental impact. The energy con-

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sumption has been analyzed for the considered FTTH architectures (Fig. 2). It has been modeled on the basis of the power consumption per port for different interface types and network elements, as shown in Table 2. These values have been extracted from vendor data sheets. It includes the energy consumption of the transceiver and the appropriate portion of the line card and basic components (chassis, switch fabric, uplink, etc.). The difference between the power consumption of interfaces with the same type can be explained by the fact that a node with a high port density is more energy efficient than a node with a low port density. Figure 3b shows the maximum energy consumption of the different FTTH architectures for one dense urban service area with 100 percent coverage, neglecting the ONT at the customer site. It is assumed that all subscribers are connected. The PtP deployment with a Gigabit-Ethernet customer interface was used as a reference case. The GPON solution needs about 84 percent less energy compared to the reference. It is also evident from Fig. 3b that a PtP deployment with a reduced bandwidth of 100 Mb/s would not lead to significant power savings. In the AON scenario the power consumption would even increase due to field deployed active switch technology. Also, in the AON case a speed reduction has almost no influence on power saving.

EVOLUTION TOWARD NETWORK CONSOLIDATION TOPOLOGY SCENARIOS In the case of reducing the total numbers of access sites when deploying optical access network technologies, new (NGOA) service areas

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have to be identified according to a number of boundary conditions: • Economic considerations: A cost-optimal cut of service areas has to be identified. • Maximum reach of access network technologies. • Limitation of the number of fibers that can be terminated in the remaining CO buildings. This refers mainly to the available capacity of the house lead-ins and feeding trunks as well as the available floor space for the optical distribution frame and active equipment, mainly the OLT devices. • Resilience requirements: The maximum number of subscribers connected to a certain CO may be limited. To identify potential new service areas by consolidation of some existing traditional service areas, we used a clustering algorithm for developing four exemplary network scenarios differing in the number of NGOA service areas. We used a reference model for Germany, and in all scenarios we started from 8000 COs and reduced the remaining number to 500, 1000, 2000, and 4000 COnew, respectively. It is obvious that other related parameters like the number of households connected to a certain access node or the covered area per NGOA service area vary in the different scenarios too. The whole NGOA service area is served by the COnew, which, however, now comprises several traditional service areas, one directly linked to the COnew and the others remotely linked to the COnew by elongated feeder links. The feeder links are interconnecting the former COs in remote service areas to the CO new . The distance for this feeder fiber depends on the number of CO new and with this on the degree of CO consolidation, and is up to about 40 km in most cases for working and backup paths (Fig. 4a). Figure 4a shows the feeder length and demand as a function of the degree of node consolidation, whereby solid lines represent the shortest working path and dashed lines show the shortest protection path, respectively. Distances above 40 km are observed only in the case of a very high degree of node consolidation (< 500 COnew/> 95 percent node consolidation) and when considering the most distant customer premises (95 percent quantile). Since in Fig. 4a only the additional feeder link length, caused by the consolidation of the CO sites, is shown, the length of the subscriber lines in the first mile (inside the traditional service area) must be added when estimating the total required reach budget of the access line system. In Germany the subscriber line length is typically below 5 km. Besides the length of the feeder links also the fiber demand in the feeder link section is an import evaluation criterion since this parameter impacts the costs of the cable infrastructure. In Fig. 4b the amount of feeder fibers needed for connecting 100 percent of all households is shown for all scenarios assuming bidirectional transmission on a single fiber and different splitting ratios. We use the splitting ratio 1:1 (pointto-point systems), 1:32 (widely used GPON splitting ratio) as well as 1:512 (feasible splitting ratios for NGOA systems). The ordinate is in

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Interface type

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1000BASE-BX

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4.4

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logarithmic scale and it is obvious that the fiber demand for p-t-p systems compared to systems providing 1:512 splitting ratio is increased by more than two orders of magnitude.

POTENTIAL TECHNOLOGIES Technologies for NGOA networks must be able to connect subscribers by optical fibers over typical distances ranging from several hundred meters up to about 60 km or even higher, taking into account protection scenarios at high bit rates and high splitting ratios of up to 1:1024. There are different options to meet these requirements: dedicated point-to-point fiber links from the CO to every subscriber, AONs with intermediate active equipment in the field, and PONs relying on a fully passive optical outside plant with power splitters. Additionally, these options can be realized in different ways regarding topology, architecture, and used technology [2]. Incumbent network operators are very much in favor of PON-based FTTH access networks due to their cost advantages in largescale network deployments with inherited passive infrastructure (proved also by the detailed cost considerations for current PON architectures in the previous section). In the case of PONs, the optical fiber as the transmission medium is shared between multiple users. There are several principal options for ensuring the necessary multi-user access: timedivision multiple access (TDMA), frequencydivision multiple access (FDMA), and code-division multiple access (CDMA), whereby from the principal point of view FDMA encompasses both wavelength-division multiple access (WDMA) and orthogonal FDMA (OFDMA) as optical technologies discussed in the PON environment. In addition, besides the multi-user access property, some of these options can be seen as efficient modulation formats, as currently discussed in case of OFDM(A). Today’s gigabit-class PON technology is based on time-division multiplexing (TDM) and a passive power splitter in the field in order to collect a number of subscribers into a single OLT port. Higher-rate TDM-PON systems have been considered for the next generation of access networks, and they rely on the same optical distribution network as the gigabit-class PON systems. PON systems with a downstream data

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Figure 4. a) Feeder link length; b) feeder fiber demand as functions of the access network node consolidation degree. rate of 10 Gb/s are standardized by IEEE and full-service access network (FSAN)/International Telecommunication Union — Telecommunication Standardization Sector (ITU-T) [3, 4]. The 10 Gigabit Ethernet PON (10G-EPON) specification has been finalized by IEEE task group 802.3av, and the 10 Gigabit PON (XG-PON) [5] has been specified by the ITU-T within the G.987 Recommendation series. Long-reach extensions of TDM-type PONs utilize intermediate reach extenders amplifying or regenerating the signal; for example, amplified long-reach GPON or 10G-PONs systems have been demonstrated. Another option for obtaining longer reach are WDM-type PONs partly relying on arrayed waveguide gratings (AWGs) as distribution elements with less attenuation — compared to power splitters — in the field. However, whether WDM PONs may reach resource allocation flexibility and necessary cost targets for mass market deployments — compared to TDM-PONs — is questionable from today’s point of view. Hybrid PONs combining WDM and TDM approaches seem to be promising solutions in order to obtain long-reach high-rate and highsplit access systems. Further interesting and promising PON approaches currently under investigation are OFDM PONs and OCDM PONs (optical CDMA). OFDM and OCDM PONs are intensely discussed in the research community. They are in an early stage of development and laboratory tests using demonstrator setups have been reported. In conclusion, there are different and very promising technology solutions for optical access systems: The main question is how these different access technology options may suit the operator’s needs to provide cost-efficient and reliable broadband access over long periods of time.

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IMPACT OF NEW BUSINESS MODELS GENERAL BUSINESS ENVIRONMENT NGOA, as it is defined in this article, assumes a FTTH network. In practice, this might be not the available network for the upcoming years. According to market data from the Organization for Economic Cooperation and Development (OECD), current digital subscriber line (DSL) coverage is about 88 percent related to the population [6]. The same report outlines that the average coverage for broadband cable is about 60 percent, but this differs across countries in Europe, and not all cable networks are upgraded yet. In addition, mobile, wireless, and satellite networks are present today with coverage of 80 percent. Fiber networks are, besides some countries, increasing but not available to a large part of the population. So starting from today, there are a number of networks available, and fiber will have to increase market share in order to become the relevant base infrastructure for NGOA. Comparing in detail the situation of today with the announcements, again a mixed view can be found. Most incumbents in large European countries have connected only few households with fiber. BT wants to connect 2.5 million homes by 2012, Deutsche Telekom announced 4 million homes for the same time frame, and Telecom Italia 13 percent of the households FTTx in 2013 and 15 percent FTTH in the long term, just to name some of the plans. In addition, a number of smaller players will start to deploy their own networks, but those numbers are so far relatively small compared with total population. While extrapolating these announcements to the 2015 or 2020 time frame (under the assumption that the targets will by accomplished), the authors assume that 20–30 percent of all households will be covered by fiber in 2015 and 30–50 percent in 2020.

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Political interest and regulation are demanding certain coverage, and this might increase the deployment speed [7]. Other important aspects are changes in the business relationships. In copper networks the incumbent has built the network and was forced either to provide appropriate wholesale products and/or to open the infrastructure. Nonetheless, the only available systems and infrastructure were provided by one player. According to the announcements, the infrastructure business will be more divided in the future, not only in terms of technology but also in terms of ownership. So the business environment might need new rules and mechanisms to work together and coexist. This will include organization of everyday processes like provisioning and forums with the aim to develop standards for the technology to be deployed. For example, in Sweden alternative network operators have already established such an organization, the Swedish Urban Network Association; in the United Kingdom BT Openreach is operating a platform called the Equivalence Management Platform (EMP: Openreach’s trading platform for Local Loop Unbundling). In addition, the trust relationship between the new alternative operators and the incumbents will change as the incumbent will be no longer the primary infrastructure provider. Overall, it can be seen that the situation is split in a number of aspects and directions, and a business framework for cooperation in NGOA networks is needed.

BUSINESS CASE ASPECTS FOR A NGOA PROVIDER The previous section outlined that there will be competition by different infrastructures and technologies. On the other hand, the active infrastructure of xDSL is no longer provided by a single player on a per country basis, and it can be assumed that this competition will still be present in the NGOA case, at least when a player reaches a significant market power and regulation comes into play. An important aspect is here cooperation whether forced, in the case of regulation, or on an open basis, like sharing active infrastructure with other providers. In any case, this demands a business relationship, which provides trust between the different parties in order to work together on a well-known basis. In addition, competition might be indirectly increased by infrastructure providers, who have the highest capital expenditures while deploying optical networks, and are looking to share these costs and retain revenues as fast as possible. Extending the viewpoint from an NGOA provider to a combined service and/or infrastructure provider/operator (like all incumbents are typically), the analysis will become even more complicated and will depend more on country specifics.

DISCUSSION OF NGOA REQUIREMENTS AND ECONOMIC OUTLOOK TECHNICAL REQUIREMENTS NGOA networks are intended to allow operators to bring down the network and production costs while at the same time ensuring high net-

work quality, availability, security, and significantly increased bandwidth per user. A number of requirements are aligned with these aspects. It is expected that the data rate demand will continuously grow over the next decades [8]. This will drive the peak rates per user to at least 1 Gb/s or even more and the committed data rate to above 0.3 Gb/s, and will force much more symmetry between downstream and upstream traffic [1]. As shown, structural network changes will be the key to optimize the network and to bring down costs. Merging access and aggregation networks into a simplified network an NGOA network will lead to cost savings resulting form better utilization of network resources (e.g., interfaces, fibers, aggregation nodes), reducing significantly the number of aggregation network elements, thus avoiding expensive signal adaptations. This restructuring of the network, however, will require much higher access reach up to 100 km, and a high customer concentration per fiber (e.g., 1024). Subsequently per cable route effective redundancy concepts and protection mechanisms for service and network availability will be required. Over the next years significant FTTH deployments are expected. NGOA systems have to work on existing first mile fiber infrastructures without requiring changes on the deployed infrastructure and deployed components. Migration to the NGOA network should not affect running services, already deployed systems and used spectra. Another key to enable further cost savings is common access for residential customers, business customers (small and medium enterprises), and mobile radio backhaul on a single NGOA network avoiding multiplied network operations and network resources is required. Efficient use of network resources requires furthermore suitable quality of service (QoS) mechanisms, resource control, and management functions to address the requirements of different user types and the mobile backhaul as well as functions enabling efficient content distribution (e.g., multicast). A huge effort is to bring down network operation cost. For the systems and architecture part, much higher energy efficiency is expected in NGOA networks. For the network operation itself, a zero touch network is expected, with high automation and support functions for basic operation processes like provisioning, maintenance, fault, and management needs to be developed that minimize manual switching efforts and increase process efficiency. A customer network termination (NT), for example, should allow doit-yourself (DIY) installation (plug and play) and be customer-unspecific (colorless) to simplify logistics. Changes in the service portfolio or the access product should be done through a selfservice approach enabled by auto-configuration functions in the network. Functions for easy, fast, and efficient maintainability and restorability are needed (e.g., seamless software upgrade without service interruption, end-to-end service/ traffic performance monitoring per customer and service). Resiliency including automatic reconnections through redundant network con-

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NGOA networks are intended to allow the operators to bring down the network and production costs while ensuring at the same time high network quality, availability, security, and significantly increased bandwidth per user. A number of requirements are aligned with these aspects.

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There are a variety of requirements on NGOA networks. Therefore the challenge is to define and select the requirements in a way to find the right balance enabling a cost optimization and establishing a network with minimum total cost of ownership.

BUSINESS CONSEQUENCES FOR TECHNICAL ASPECTS

DIRK BREUER ([email protected]) ____________ received Dipl.-Ing. and Dr.-Ing. degrees in electrical engineering from the Technical University of Berlin in 1993 and 1999, respectively. Since joining Deutsche Telekom Laboratories, he has mainly been concerned with developing optimization strategies for the optical transport network of Deutsche Telekom. In recent years he is mainly involved in developing upgrade strategies toward next-generation broadband access networks.

With respect to technology, there are a lot of options to establish next-generation access networks. In this section some points are highlighted that are related to the interrelationship between the business and technology aspects. Provided that there is competition and open access in next-generation access networks, it will be important to consider the market share and the related number of customers in order to fill possible long-reach PONs with high splitting ratios. Technically, it would be possible to extend the access up to 100 km, but for business needs and the open access model, new interfaces — possibly active — are necessary and may be contradictory to the node consolidation approach. These are important for establishing and operating access networks in changing business environments cost efficiently. From the operators’ point of view, one main requirement is upgrading either bandwidth or systems on existing fiber infrastructure as long as possible since infrastructure investment is the big bulk. Another point is changing systems under almost running conditions. This needs to be considered from the beginning. In consequence, cost efficiency in network installation and operation is key for network operators. It requires finding a balance between pure technical and business problems. Bringing all these problems together is still open from today’s point of view, and requires further research and in-depth investigations which will be conducted to a certain extent in current FP 7 projects like OASE.

REFERENCES [1] Analysis Mason, “Fibre Capacity Limitations in Access Networks,” report for OFCOM, Jan. 2010. [2] Optical Access Seamless Evolution (OASE), “Survey of NGOA system Concepts,” FP7/2007–2013, deliv. D4.1; http://www.ict-oase.eu/. [3] J. Kani et al., “Next-Generation PON Part I — Technology Roadmap and General Requirements,” IEEE Commun. Mag., vol. 47, no. 11, 2009, pp. 43–49. [4] F. Effenberger et al., “Next-Generation PON Part II — Candidate Systems for Next Generation PON,” IEEE Commun. Mag., vol. 47, no. 11, 2009, pp. 50–57. [5] F. Effenberger et al., “Next-Generation PON Part II — System Specifications for XG-PON,” IEEE Commun. Mag., vol. 47, no. 11, 2009, pp. 58–64.

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[6] A. Díaz-Pinés, “Indicators of Broadband Coverage,” OECD, DSTI/ICCP/CISP(2009)3/FINAL. [7] Booz & Company, “NGNBN Case Studies — Next Generation National Broadband Network Country Profiles,” July 2009; _______________________ http://www.booz.com/media/file/NGNBNCountry-Profiles.pdf ___________ [8] Cisco Systems, “Cisco Visual Networking Index: Forecast and Methodology, 2009–2014,” San Jose, CA, 2009; http://www.cisco.com/en/US/solutions/collateral/ns341/n s525/ns537/ns705/ns827/white_paper_c11-481360.pdf.

ACKNOWLEDGMENTS

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cepts should minimize the effect of failures, but to prevent and clear failures, suitable fault management supported by optical diagnosis and measurement solutions for fault detection and localization up to the home are necessary. There are a variety of requirements for NGOA networks. Therefore, the challenge is to define and select the requirements in a way to find the right balance, enabling cost optimization and establishing a network with minimum TCO.

The work leading to these results has received funding from the European Union’s Seventh Framework Program (FP7 2007/2013) under grant agreement no. 249025 (project: Optical Access Seamless Evolution — OASE).

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F RANK G EILHARDT ([email protected]) ________________ received a Dipl.-Ing. (FH) degree in telecommunication engineering from the University of Applied Sciences of Berlin in 2001. Afterward he started to work in the Fixed Access Network Group of T-Systems Nova GmbH that was merged into TSystems Enterprise Services GmbH. In 2009 he joined Deutsche Telekom Laboratories in Berlin. Since joining TSystems he was mainly concerned with access network evolution including techno-economic assessments as well as the operation of access technology demonstrators. RALF HÜLSERMANN ([email protected]) _________________received a Dipl.-Ing. (FH) degree in telecommunication engineering from the University of Applied Sciences of Leipzig in 2001. Since joining Deutsche Telekom AG in 2001 he has been concerned with architectures for optical transport networks. Currently he is with Deutsche Telekom Laboratories where he is mainly involved in planning and optimizing optical access networks with focus on techno-economic assessment. M ARIO K IND ([email protected]) ______________ received a Dipl.-Inf (FH) degree in communications and information technology at Deutsche Telekom Hochschule für Telekommunikation Leipzig (FH), University of Applied Sciences (HfTL). He is employed as an expert in the area of broadband access networks. His main working area is the economic evaluation of business, technology, and service trends in the Internet, telecommunication, and broadcast industry. He is author or co-author of several papers published in international telecommunications conferences and journals. C HRISTOPH L ANGE ([email protected]) _________________ is with Deutsche Telekom Laboratories, the research department of Deutsche Telekom AG, Berlin, Germany. He received a Dipl.-Ing. degree (diploma) in electrical engineering and Dr.-Ing. degree (Ph.D.) in communications engineering from the University of Rostock, Germany, in 1998 and 2003, respectively. His current research interests include broadband networks, emphasizing access network topics as well as the energy consumption and sustainability of telecommunication networks. THOMAS MONATH ([email protected]) ________________ received his Diplom-Ingenieur (M.S.) degree in communication engineering from the University of Rostock in 1997. After finishing studies he joined Deutsche Telekom. He is working as a senior expert in techno-economics of telecommunication networks and as a project Leader (PMP) of strategic access network evolution projects. He has been involved in several European projects of EURESCOM, ACTS, and IST focused on broadband access network evolution. He is author or co-author of several papers published in international telecommunications conferences and journals. E RIK W EIS ([email protected]) _____________ received a Dipl.-Ing. degree in electrical engineering from the Technical University of Dresden. He joined the Research Institute of Deutsche Telekom in 1997, where he was involved in national and international R&D projects on optical and hybrid optical broadband access networks. His current research interests include developing upgrade strategies and concepts toward next-generation broadband optical access networks.

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ADVANCES IN PASSIVE OPTICAL NETWORKS

Cost and Energy Consumption Analysis of Advanced WDM-PONs Klaus Grobe, Markus Roppelt, Achim Autenrieth, Jörg-Peter Elbers, and Michael Eiselt, ADVA AG Optical Networking

ABSTRACT Next-generation access systems will have to provide bandwidths in excess of 100 Mb/s per residential customer, in conjunction with high customer count and high maximum reach. Potential systems solutions include several variants of WDM-PONs. These systems, however, differ significantly in their cost (capital expenditures) and energy consumption potential. We compare several WDM-PON concepts, including hybrid WDM-PON with integrated per-wavelength multiple access, with regard to these parameters. We also show the impact and importance of generic next-generation bandwidth and reach requirements.

INTRODUCTION Residential access bandwidth is ever increasing, and today, no change in this trend can be seen. Future applications that can easily fill bandwidths in excess of (several) 100 Mb/s consist of a combination of ultra-high-definition threedimensional TV with time-shifted or peer-topeer unicast. It can already be predicted that even fiber access based on Ethernet/gigabitcapable passive optical network (EPON/GPON) and their successors, 10G-EPON and XG-PON1, will reach its limit and is not suitable for that kind of application. So a new generation of broadband access systems will be required. These access systems are also referred to as next-generation PON, or NG-PON2 in full-service access network (FSAN) terminology [1] and are likely to be more than five years away from now. During this time, active site reduction and network consolidation will lead to larger reach requirements for the access and backhaul systems, with remaining sites having to serve a significantly larger number of customers [2]. The new technology will likely be based on wavelength-division multiplexing (WDM), possibly in conjunction with suitable wavelength sharing schemes. Following cost expectations and energy-consumption predictions [3], much focus with regard to next-generation access systems is put on advanced PON concepts. There is, however, much uncertainty about the respective ranges of these requirements. The

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different requirements regarding reach and client count as well as the requirements with respect to the optical distribution network (ODN) have severe impact on the potential capital expenditures (CapEx) and also on the operational expenditures (OpEx) of the resulting systems solutions. This is discussed in detail in the next sections. Regarding OpEx, we concentrate on energy consumption, as this constitutes a large part of these costs. Other differences in operation expenses resulting from operations and maintenance are hard to quantify, and might not even be fully appreciated by the network operators.

BROADBAND APPLICATIONS Today, there is much debate about a useful broadband definition for residential access. Sometimes, bandwidths starting at 1 Mb/s are referred to as broadband, sometimes this is increased to the range of 10 Mb/s, but sometimes, a definition of 256 kb/s has been used [4]. It is obvious that the broadband definition is frequently adopted toward increased bandwidth values. This discussion often leaves the downstream (central office or point of presence to customer) vs. upstream (the counter-direction) asymmetry unconsidered. Here, we refer to broadband access as an infrastructure which is able to potentially scale to beyond 1 Gb/s of sustained bandwidth per residential customer. Oversubscription, or statistical multiplex bandwidth gain, can be applied in a dedicated aggregation layer. This aggregation may be implemented at the edge to the backhaul and core parts of the network and can lead to significantly decreased sustained bandwidths. However, the transport and multiple-access parts of the access infrastructure should still enable sustained bandwidths in the range of 1 Gb/s. On a broad scale, bandwidths beyond, say, sustained 100 Mb/s should be provided via a fiber-based infrastructure (fiber to the home [FTTH] or fiber to the building [FTTB]), mostly due to cost and energy consumption reasons [3]. FTTH and FTTB require a massive, very costly infrastructure to be overbuilt. Hence, the nextgeneration infrastructure in turn must not be limited to anything below 1 Gb/s for reasons of investment security.

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A chicken-egg play: we do not see broadband peer-topeer applications today, which is likely due to the fact that upstream bandwidth is not available in the

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Figure 1. Downstream and upstream bandwidth requirements and capabilities of different (near-future) services and solutions.

application. It is easy to envisage future services that can fill these bandwidths. This even holds for symmetric downstream-upstream scenarios. From today’s viewpoint, one application in particular can be identified which could make use of bandwidths approaching, and possibly exceeding, 1 Gb/s — unicast highest-resolution video, in conjunction with symmetric-bandwidth peer-to-peer applications. Today’s high-definition television (HDTV) requires bit rates between 8 and 15 Mb/s, depending on the compression efficiency (of the Moving Pictures Experts Group’ MPEG4 or International Organization for Standards/International Electrotechnical Commission [ISO/IEC] 14496 standard). The next step beyond HDTV is already clear — ultra-HDTV (UHDTV), with a resolution of today 3840 × 2160, in future 7680 × 4320 pixels, with 16:9 format, 60 Hz frame rate, and 22.2 audio (24-channel audio, including two subwoofer channels). These formats are also referred to as 4k and 8k UHDTV, respectively. They have been developed by the Japanese TV broadcast company NHK, together with the consumer systems industry. According to [5], it is likely that the 8k format will require up to 200 Mb/s per channel (72 Gb/s uncompressed). Furthermore, 3D versions of UHDTV may require up to 180 percent increased bit rate compared to 2D. Combined with time-shifted unicast or even peer-to-peer applications, these formats will then fill bandwidths up to the 400 Mb/s range. They will have to be provided — in the busy hour — via sustained bandwidth, without further oversubscription in the access network. The respective (downstream) UHDTV bandwidth will need to be at least twice that per typical household, assuming two parallel independent downstream or download sessions. Concerning the upstream direction, a similar bandwidth may be required in peer-to-peer applications. Here, a chickenegg problem comes into play: we do not see broadband peer-to-peer applications today, which is likely due to the fact that the required upstream bandwidth is not available in the

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majority of today’s access installations. Once the bandwidth is provided, it may thus fuel the application. The downstream and upstream bandwidth requirements of corresponding applications are compared in Fig. 1, together with the bandwidth capabilities of some of today’s access solutions with the highest bandwidth. Here, we assume an UHDTV bandwidth of only 75 Mb/s, which caters to the uncertainty about future codec efficiency and 3D overhead. It is also not clear what bit rate requirements may come after 8k 3DUHDTV. The authors hence believe that any new access infrastructure must be able to potentially deliver bit rates that are considerably higher than the requirements shown in Fig. 1.

BROADBAND ACCESS SOLUTIONS As discussed earlier, we focus on fiber-based next-generation broadband access. This refers to both FTTH and FTTB scenarios, where FTTH is more likely to be the broadband access endgame, and FTTB may be seen as one of the migration scenarios and also as an alternative in cases where optical in-house cabling is difficult or impossible. The main reason for this fiber access focus can also be derived from Fig. 1: for access bandwidth requirements in the 100 Mb/s range and beyond, there are no efficient alternatives. Clearly, DOCSIS3.0 and VDSL2 can exceed 100 Mb/s, but the former is a shared medium incapable of providing high dedicated bandwidth to all customers in a cluster at the same time, and the latter is severely limited in reach for bandwidths exceeding 50 Mb/s. In addition, both will lead to higher energy consumption than the PON candidates due to the fact that they are based on copper cabling. Figure 1 also gives the comparison of GPON and WDM-PON downstream and upstream capabilities. From this comparison it can be derived that GPON, in particular when it comes to unicast and symmetric-bandwidth applications, cannot meet the requirements by 2020. The same is true for EPON and the successors, XG-PON1 and

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10G-EPON. The proposed solution to the scalability requirement is an access technology that scales through the use of WDM. If this is combined with a passive ODN for cost and energy consumption effectiveness, we refer to it as a WDM-PON. WDM-PONs have been considered for quite a while as promising contenders for next-generation access [6, 7]. To the knowledge of the authors, only Korea Telecom has deployed an early implementation of a WDM-PON so far. The lack of further installations is mostly attributed to missing international standardization and cost efficiency. This is expected to change once the International Telecommunication Union (ITU) or IEEE provides relevant standards. Increased deployment numbers enabled by standardization will in turn lead to decreased WDM-PON cost.

REQUIREMENTS As mentioned in the introduction, the requirements for next-generation PONs vary a lot. The key performance indices are dedicated data rate per customer, total customer count, and maximum reach. With regard to customer count, anything between 64 and several thousand is stated [8]. Concerning maximum reach, the range from 50 to >100 km is covered. Only the bandwidth requirements seem to be clear: whatever the next generation of access is, it will have to support per-client bandwidth, which may go beyond 1 Gb/s in the long term. In order to limit the candidates, the next-generation access configurations considered here were required to support >100 customers with a sustained bandwidth of >500 Mb/s each. Minimum reach requirement for the ODN without additional reach extension was set to at least 50 km. To the best of our knowledge, these numbers represent what can be considered sufficient for 2020. It also has to be noted that, in particular, the sustained per-client bandwidth can be increased to 1 Gb/s (and potentially more) through reconfigurations of the respective solutions.

OPTICAL DISTRIBUTION NETWORK Taking reach extension into account, the key requirements will also support reduction of active sites by an order of magnitude, and hence longer distances in the ODN. It is not clear yet if a fully passive ODN is required, or if the ODN may accommodate a certain amount of active equipment. This is considered very important since it has an obvious impact on the accumulated insertion or path loss of the end-to-end ODN. Combining an optical power splitter/combineronly ODN with the requirement to support very high customer count, say in clear excess of 100, leads to high insertion/path loss. On the other hand, in order to keep any next-generation access technology competitive, it must be restricted in its available power budget. This is demonstrated in Fig. 2. Figure 2 shows the accumulated insertion loss for PONs with power splitters/combiners only, filters (arrayed waveguide gratings [AWGs]), band-splitters and interleavers only (i.e., a pure WDM-PON), and hybrid PON with both power

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Splitter only 1:8 TFF + Splitter 1:80 AWG + S/C + IL 1:80 AWG + Splitter

40

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Figure 2. Accumulated insertion loss of power-splitter PON, filter-based (WDM-) PON, and hybrid filter-plus-splitter PON. TFF is a thin-film filter, S/C is an additional S/C-band splitter, IL is an interleaver, and AWG is an arrayed waveguide grating. splitters/combiners and filters. The light-grey area indicates the region for a pure WDM-PON that can be covered with cheap (positive-intrinsic-negative [PIN] photo-diode-based) transceivers and leaves enough power budget for the ODN fiber to cover distances of 40–60 km. For the hybrid infrastructure, it is assumed that the interfaces have a total bandwidth of 10 Gb/s in order to provide sufficient per-client bandwidth after the power splitter. It becomes clear that this infrastructure does not allow use of the cheapest transceivers since these have to support 10 Gb/s accumulated bandwidth, a multiple access mechanism, and also higher total power budgets for per-wavelength split ratios exceeding 1:4. It is also obvious that higher numbers of wavelengths decrease the insertion loss for hybrid infrastructure. The black squares and diamonds in Fig. 2 indicate the range for the split ratio where up to 1 Gb/s per client can be guaranteed when using 10 Gb/s total per-wavelength capacity. For split ratios >1:8 (white squares and diamonds), this is not possible anymore at 10 Gb/s per wavelength. For the splitter-only infrastructure, very high split ratios result in very high insertion loss exceeding 30 dB. This infrastructure can only be supported by means of coherent ultra-dense WDM (UDWDM). Then ultra-densely spaced (i.e., < 12.5 GHz) wavelengths with dedicated per-client bandwidth of 1 Gb/s can be used. Coherent technology can provide the necessary power budget to cope with the insertion loss. However, it is doubtful that it can achieve the cost points of the much simpler filter-based (or wavelength-routed) WDM-PON. It must be noted that in Fig. 2, we calculated the insertion loss for the ODN power splitters/combiners only. In an ultra-dense WDM-PON (UDWDM-PON), the transceivers in the optical line terminal (OLT, i.e., the central office equipment) have to be combined by means of splitters and/or filters as well. These additional combiners must be considered when designing the respective OLT transceiver array.

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COMPARED SOLUTIONS The lasers must be very precisely tunable to maintain the ultra-dense spacing. This is achieved by heterodyne closedloop control and may require additional environmental control. It is therefore doubtful if uncooled, low-cost lasers can be used in this scheme.

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Several WDM-PONs and derivatives have been discussed so far [6, 7]. These include plain WDM-PON, which only makes use of wavelength-division multiple access (WDMA), as well as more sophisticated so-called hybrid PON and UDWDM-PON. Hybrid PON refers to combinations of WDM transport and multiple access (WDMA) and additional per-wavelength multiple access mechanisms like time-division multiple access (TDMA), subcarrier multiple access (SCMA), and code-division multiple access (CDMA). WDM-, hybrid, and UDWDM-PON are not equally capable of supporting all next-generation requirements (high client count, high dedicated per-client bandwidth, long reach), regardless of the exact numbers. In addition, they differ significantly in estimated per-client cost (CapEx) and per-client end-to-end energy consumption. These two parameters are very important on a broad scale with millions of subscribers. Hence, a detailed analysis is required, and is provided hereinafter. We restrict our analysis to fiberbased solutions that use WDM filters in the ODN due to the considerations in the last section. The schematic diagrams of the considered architecture alternatives are compared in Fig. 3. The WDM-PON shown in Fig. 3a makes use of the C-, L-, and S-bands, which are accessible via a cyclic AWG. Today, such AWGs (which also cover further bands like the extended Lband) are available for 32 ports and channel spacing in the 100 GHz range. Non-cyclic lowloss AWGs are available that support 96 channels at 50 GHz. We expect that cyclic 50 GHz AWGs with port counts between 64 and 96 will become available very soon. The WDM-PON is further based on highly integrated photonic integrated circuits (PICs), which contain the OLT transceiver arrays, and low-cost tunable lasers in the optical networking units (ONUs, i.e., the client equipment). PICs are considered necessary in order to reduce both power consumption and form factor in the OLT. The tunable ONU transmitters can be based on monolithic multisection distributed Bragg reflector (DBR) lasers (e.g., SG DBR or DS DBR lasers). Uncooled operation without thermo-electric cooling (TEC) of these devices has already been demonstrated [9]. TEC-less operation is required in order to achieve the lowest power consumption. It is also frequently required by large network operators. For lowest cost, the ONU lasers will also not get their own dedicated wave lockers. They will then have to be wavelength-tuned via closed-loop control, which incorporates feedback signals from either the OLT or the PON remote node. The active/passive hybrid PON shown in Fig. 3b connects access switches (active part) via passive WDM (passive backhaul part) running 10 Gb/s per wavelength. Tunable extended-formfactor pluggables (XFPs) can be used for the WDM backhaul, and lowest-cost grey small form-factor pluggables (SFPs) can be used for the active point-to-point access. The passive WDM part can also be used for generalized backhaul. This combination has potential for

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very high per-client and total capacity and long reach in excess of 60 km. It requires, however, the accessibility of the respective active sites for the access switches. Figure 3c shows a hybrid WDM/TDMA-PON. For our analysis, we considered DWDM-colored TDMA at symmetric 10 Gb/s (per pair of wavelengths). This can be regarded as an extension of the stacked XG-PON approach. It can enable both high split ratio and high capacity. However, it leads to the necessity for 10 Gb/s TDMA (burst-mode) transceivers, which have up to 35 dB power budget. In addition, the transceivers must be tunable or be based on seeded reflective technology [6] (i.e., reflective electro-absorption modulator-semiconductor optical amplifier [REAM-SOA] combinations). The latter, however, lack long-distance capability because of Rayleigh crosstalk or require dedicated seed fibers [10]. The OLT again makes use of photonic integration. Finally, Fig. 3d shows a diagram of a coherent UDWDM-PON. Heterodyne detection is used in order to reuse the local oscillator laser also for the respective upstream or downstream signal transmission. In the OLT several channels can be integrated in broadband multichannel transceivers, thus reducing cost. In the ONUs, narrow-line-width lasers are required. If quaternary phase shift keying (QPSK) at 1 Gb/s is used, the line width must not exceed ~200 kHz [11]. The lasers must be very precisely tunable to maintain the ultra-dense spacing. This is achieved by heterodyne closed-loop control and may require additional environmental control. It is therefore doubtful that uncooled low-cost lasers can be used in this scheme. The coherent detection scheme also requires polarization control, diversity, or scrambling (Pol. Scr. in Fig. 3) mechanisms [12], which further increase complexity and cost. On the other hand, power budget of >45 dB is possible which allows the combination of very high customer count (up to and exceeding 1000), dedicated 1 Gb/s per customer, and long reach in excess of 50 km. Note that in Fig. 3d, a hybrid infrastructure with 100 GHz AWGs and subsequent power splitters/ combiners is shown. The AWG first routes groups of tightly spaced wavelengths to the respective ports. These wavelength groups are then split in the splitters/combiners. This approach requires gaps between the wavelength groups to allow for filtering, but leads to significantly decreased insertion loss compared to the splitter/combiner-only configuration.

COST AND ENERGY CONSUMPTION For a comparison of cost and energy consumption, the respective contributions of all major components must be considered. One major difficulty results from the fact that not all components are commercially available today. Parts of these components are not even technically mature yet. This leads to the necessity of predicting both cost and power consumption that these components will have. This prediction has been done based on the complexity (functionality), optical power budget, and bandwidth processing requirements of the respective components.

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Figure 3. Schematic diagrams of broadband next-generation access solutions: a) a basic C+L+S-band WDM-PON for 128-192 bidirectional channels — L/C, C/S, and R/B are the respective band filters, with R, B the Red and Blue sub-bands in the S-band; RXA, TXA: transmit and receive arrays, RN: remote node, SFF: small form factor transceiver, including a tunable laser diode (T-LD); note that only the WDM-PON in 3a is based on a filter-only ODN; b) an active/passive WDM hybrid PON, where the backhaul part is based on passive WDM and the last-mile access is based on active (Ethernet) point-to-point; TXFP, SFP: tunable extended and small form-factor pluggables, ARN and PRN: active and passive RN; c) a WDM/TDMA hybrid PON running (symmetrical) 10 Gb/s TDMA on each wavelength pair. MDXM:mux/demux, APD: avalanche photo diode, SOA: semiconductor optical amplifier, CLK Rec.: clock recovery; d) a coherent UDWDM-PON with cascaded filters and power splitters/combiners in the ODN. ADC and DAC: analog-digital and digital-analog conversion, US: upstream, DS: downstream, RF: radio frequency, Pol. Scr.: polarization scrambler. Where possible, we considered the nearest or most sophisticated components available today, and estimated their cost and power consumption decrease over the next years, assuming mass production (examples: tunable XFPs, grey SFPs). Also note that, for example, the tunable XFPs will be produced in significantly smaller numbers than the lowest-cost tunable ONU transceivers

(TRXs). The respective cost impact has been considered. The cost and power consumption assessment has been performed, to the best of our knowledge, with equally challenging assumptions for all components. The resulting cost and power consumption figures were discussed with component and system vendors, and also network operators at FSAN.

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Table 1. Cost and energy-consumption parameters.

Table 1 gives an overview of cost and power consumption figures of the most relevant components for the systems shown in Fig. 3. Cost figures have been normalized to the common baseline costs of the solutions, which are the costs for common parts such as shelves and management controllers. From Table 1, the most relevant components can be identified. In the first place the transceivers, which are required on a per-client basis, determine the resulting cost and also part of the power consumption. With regard to cost, the common contribution from shelves, power supply units, management controllers, interfaces, and so on are in second place. Regarding power consumption, these common components are already the main contributor. Solution-specific application-specific integrated circuits (ASICs), switches, and the perport contribution from filters (AWGs) and splitters/combiners are of least importance. The results for cost and power consumption of the four solutions compared in Fig. 3 are listed in Table 2. They are split into contributions from the ONU, OLT, and remote node. The results are also visualized in Fig. 4. From the analysis, it can be seen that a pure WDM-PON clearly has the lowest per-client (end-to-end) power consumption, and almost lowest per-client cost. Again, plain WDM-PON refers to a system without any further added

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multiple access mechanism or coherent detection, using filters rather than splitters/combiners. The per-client end-to-end connection includes the complete ONU, the respective portion of the remote node (RN; with regard to power consumption, there is only a contribution for the active/passive hybrid PON), and the respective portion of the OLT node. The latter includes transceivers, any electronics necessary for modulation, multiple access and signal processing, and also the respective portion of an aggregation switch. We attribute the WDM-PON performance to the possibility to use cost-effective simple transceivers (27 dB class with PIN photo diodes, 1 Gb/s bandwidth, monolithically integrated lasers, no complicated medium access control [MAC] layer or multiple access). In turn, such transceivers are allowed because filters are used in the ODN rather than power splitters/combiners. According to the numbers in Table 2, the active/passive hybrid system leads to lowest cost (although the difference against the WDM-PON is small), and also has second best power consumption. Per-client power consumption is increased by 0.8 W. Note that this difference is produced mainly in the added active sites. The relatively good cost and power consumption performance of this solution can mainly be attributed to the use of lowest-cost lowest-complexity very-low-power-consuming grey transceivers

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Common baseline

Energy consumption

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Table 2. Results of cost and power consumption analysis for next-generation access.

(SFPs) for the active access links. Today, such SFPs are available with power consumption going down to 0.4 W and cost going down into the range of US$20. These numbers cannot be achieved with any other transceiver class (10G, added multiple access, high power budget, etc.). We note, however, that this solution will not be accepted by every network operator due to the necessity of active sites. The hybrid WDM/TDMA-PON is higher in cost and power consumption than the two first solutions. Compared to the WDM-PON, cost is ~27 percent higher. This can be regarded as a reasonable cost markup given the fact that the WDM/TDMA-PON can support a larger number of clients over a purely passive ODN. Power consumption, however, is increased by 1.3 W/client. This difference is partly spent in the ONU and is likely to be paid by the customers, not the network operator or service provider. On a global scale, at high take rate of the respective technology, the question remains if such a difference is acceptable in the context of green IT. An advantage of this solution is the support of GPON access infrastructure, together with the filter-based backhaul. It also has to be noted that other WDM hybrid schemes (based on added SCMA or CDMA) from today’s perspective do not seem to offer advantages over the WDM/TDMA hybrid PON. According to our analysis, the UDWDMPON leads to highest cost and also highest power consumption. Cost compared to the simpler DWDM-PON is 165 percent, and per-client power consumption is higher by 2 W. We attribute these differences to the necessary added complexity of coherent detection, which includes tight wavelength control, added (digital or analog) signal processing, ultra-narrowlinewidth lasers, polarization control, diversity, or scrambling, and also the need for balanced receivers with multiple photo diodes. Clearly, a UDWDM-PON has very high optical performance and is able to potentially support more than 1000 clients via a splitter infrastructure or, using WDM filters, over very long access distances in excess of 100 km. Here, the most important question is whether or not this technology is overengineered for the majority of applications or clients (which will require significantly less reach performance than 100 km).

So far, we have not considered means other than PICs and TEC-less lasers for reduction of power consumption in WDM-based PONs. Besides general power consumption reduction in (opto-) electronic components, reduction in WDM-PON can be achieved through so-called doze or (cyclic) sleep modes, where either transmitters are deactivated when not used, or complete transceivers are periodically deactivated. Such power-saving modes are expected to be simpler in implementation and more power-saving-efficient in WDM-PONs than the ones known from GPON since no common MAC layer has to be kept alive.

CONCLUSION We have shown that a simple WDM-PON is most efficient for next-generation access with up to 1 Gb/s (sustained) per client and client numbers not exceeding 128–192. Access distances of 40–60 km can also be supported. This can clearly be attributed to the inherent simplicity of the transceivers and the multiple access mechanism that can still be used for these numbers. Other solutions — hybrid WDM/TDMA, UDWDM, or active-plus-passive hybrid — exist, but either lead to higher cost and power consumption, or require active sites which may contradict site consolidation programs of certain network operators. We conclude that it is essential to carefully clarify the requirements for next-generation access with regard to per-PON client count and maximum reach. The question of whether WDM filters are allowed in the ODN (instead of power splitters/combiners) also has to be answered, and the same is true for active equipment in the access network. In particular, if client count does not exceed 128–192, and a passive filter-based ODN is accepted, the most efficient solution with regard to both cost and power consumption is a simple WDM-PON. This client-count range may even be increased to 256–384 by using interleavers in order to effectively use a 25 GHz DWDM grid.

ACKNOWLEDGMENT The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/20072013) under grant agreement no. 249025

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(ICT-OASE) and from the German Ministry for Education and Research (BMBF) under Grant 13N10864.

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[1] J. Kani and R. Davey, “Requirements for Next Generation PON,” ITU-T/IEEE Wksp. NGOA Sys., Geneva, Switzerland, June 2008. [2] M. Fricke, “Examining the Evolution of the Access Network Topology,” IEEE GLOBECOM ‘09, Honolulu, HI, Dec. 2009. [3] R. Tucker, “Optical Packet-Switched WDM Networks: a Cost and Energy Perspective,” OFC/NFOEC ‘08, San Diego, CA, Feb. 2008. [4] OECD, “Broadband Statistics”; http://www.oecd.org/sti/ict/broadband. [5] T. Kuroda, “Current Status on Super HDTV Development in Japan,” IEEE Int’l. Symp. Broadband Multimedia Sys. Broadcasting, 2010. [6] A. Banerjee et al., “Wavelength-Division Multiplexed Passive Optical Network (WDM-PON) Technologies for Broadband Access: A Review,” J. Optical Net., vol. 4, no. 11, Nov. 2005, pp. 737–58. [7] K. Grobe and J.-P. Elbers, “PON in Adolescence: From TDMA to WDM-PON,” IEEE Commun. Mag., vol. 46, no. 1, Jan. 2008, pp. 26–34. [8] R. P. Davey et al., “Long-Reach Access and Future Broadband Network Economics,” ECOC ‘07, Berlin, Germany, Sept. 2007. [9] Y. Liu et al., “Directly-Modulated DS dBR Tunable Laser for Uncooled C-band WDM System,” OFC ‘06, Anaheim, CA, Mar. 2006. [10] G. Talli and P. D. Townsend, “Hybrid DWDM-TDM Long-Reach PON for Next-Generation Optical Access,” IEEE J. Lightwave Tech., vol. 24, no. 7, July 2006, pp. 2827–34. [11] M. Seimetz, “Laser Linewidth Limitations for Optical Systems with High-Order Modulation Employing Feed Forward Digital Carrier Phase Estimation,” OFC/NFOEC ‘08, San Diego, CA, Mar. 2008. [12] J. M. Fabrega and J. Prat, “New intradyne Receiver with Electronic-Driven Phase and Polarization Diversity,” OFC ‘06, Anaheim, CA, Mar. 2006.

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Figure 4. Per-client end-to-end power consumption (top) and relative cost (bottom) of the four solutions, broken down into the main contributions of each.

BIOGRAPHIES KLAUS GROBE [M‘94] received Dipl.-Ing. and Dr.-Ing. degrees in electrical engineering from Leibniz University, Hannover, Germany, in 1990 and 1998, respectively. Since 2000 he has been with ADVA AG Optical Networking. He has authored or co-authored three book chapters on WDM and PON technologies, and more than 70 scientific papers. He is a member of the IEEE Photonics Society, OFC Subcommittee F, the German VDE ITG, and ITG Fachgruppe 5.3.3 (Photonic Networks). JÖRG-PETER ELBERS received his diploma and Dr.-Ing. degrees in electrical engineering from Dortmund University, Germany, in 1996 and 2000, respectively. In 1999–2001 he was with Siemens AG — Optical Networks, as director of network architecture. In 2001 he joined Marconi Communications as director of technology. Since September 2007 he has been with ADVA AG Optical Networking, where he is vice president of advanced technology. He authored and co-authored more than 70 scientific publications and holds 14 patents. M ARKUS R OPPELT received a diploma degree in electrical engineering from the Karlsruhe Institute of Technology (KIT), Germany, in 2009. He is currently working toward a

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Ph.D. degree in electrical engineering at ADVA AG Optical Networking. His current primary research interest is in nextgeneration optical networks. M ICHAEL E ISELT [SM] received his Dr.-Ing. degree in photonics from the Technical University of Berlin in 1994. During his 20-year career in optical communications, he has worked at various companies and research organizations in Germany and the United States. As director of advanced technology at ADVA Optical Networking, he is currently leading physical layer research for high-speed and access applications. He is a Fellow of the Optical Society of America. A CHIM A UTENRIETH [M] received his Dipl.-Ing. and Dr.-Ing. degrees in electrical engineering and information technology from Munich University of Technology (TUM), Germany, in 1996 and 2003, respectively. From 2003 to 2010 he was with Siemens AG, Siemens Networks GmbH & Co KB, and Nokia Siemens Networks, last as head of BCS R&D Innovations. Since 2010 he is with ADVA AG Optical Networking, Advanced Technology. His research interests include multilayer transport networks and control planes. He is a member of VDE/ITG.

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ADVANCES IN PASSIVE OPTICAL NETWORKS

Toward Energy-Efficient 1G-EPON and 10G-EPON with Sleep-Aware MAC Control and Scheduling Jingjing Zhang and Nirwan Ansari, New Jersey Institute of Technology

ABSTRACT To rapidly meet increasing traffic demands from subscribers, the IEEE 802.3av task force was charged to study the 10G-EPON system to increase the data rate to 10 times the line rate of 1G-EPON. With the increase of the line rate, the energy consumption of 10G-EPON increases accordingly. Achieving low energy consumption with 10G-EPON has attracted broad research attention from both academia and industry. In this article we first briefly discuss the key features of 10G-EPON. Then, from the perspective of MAC-layer control and scheduling, we discuss challenges and possible solutions to put optical network units into low-power mode for energy saving. More specifically, we detail sleep-mode control and sleep-aware traffic scheduling schemes in two scenarios: sleep for over one DBA cycle, and sleep within one DBA cycle.

INTRODUCTION As one of the major fiber to the home/curb/cabinet/and so on (FTTx) technologies, Ethernet passive optical network (EPON) is developed based on Ethernet technology, and enables seamless integration with IP and Ethernet technologies [1]. Due to the advantages of fine scalability, simplicity, and multicast convenience, as well as the capability of providing full-service access, EPON has been rapidly adopted in Japan and is also gaining momentum with carriers in China, Korea, and Taiwan since the IEEE ratified EPON as the IEEE 802.3ah standard in June 2004. On the other hand, video-centric applications and services such as HDTV are growing and emerging in the network [2]. As compared to traditional voice and data traffic, these multimedia applications are more bandwidth-hungry. For example, one HDTV channel requires as much as 10 Mb/s bandwidth. Motivated by satisfying these emerging high bandwidth demands, the IEEE 802.3av 10G-EPON task force was charged to increase the downstream bandwidth to 10 Gb/s, and to support two upstream data rates: 10 Gb/s and 1 Gb/s. While the line rate is significantly increased

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to satisfy subscribers’ demands, the power consumption of 10G-EPON may be increased as well [3]. Power consumption of 10G-EPON has become a big concern of network service providers as it contributes to part of their operational expenditure (OPEX). Moreover, energy consumption is becoming an environmental and therefore social and economic issue because one big reason for climate change is the burning of fossil fuels and the direct impact of greenhouse gases on the Earth’s environment [4]. Previously, Baliga et al. [5] estimated that the Internet currently consumes around one percent of the total electricity consumption in broadband enabled countries. It is also shown that currently and in the medium term future, access networks consume the majority of the energy in the Internet. The analysis in [5, 6] showed that, among various access technologies, such as WiMAX, fiber to the node (FTTN), and point-to-point optical access networks, PON is the most power-efficient solution in terms of energy consumption per transmission bit attributed to the nearest approach of optical fibers to users. Although PON consumes the smallest power among all access network technologies, it is desirable to further reduce its power consumption, especially when the line rate is increased to 10 Gb/s. With the increase in line rate, the optical dispersion increases as well. Compensating for higher dispersion exerts higher requirements on optical lasers, which may incur an increase of power consumption of lasers. In addition, the electronic circuit should be sufficiently powered such that it can process 10 times faster than that of 1G-EPON. Thus, 10G-EPON will consume more energy than 1G-EPON [4, 5]. Reducing power consumption of 10G-EPON requires efforts across both the physical and medium access control (MAC) layers. Efforts are being made to develop optical transceivers and electronic circuits with low power consumption. Besides, multi-power-mode devices with the ability of disabling certain functions can also help reduce the energy consumption of the network. However, low-power-mode devices with some functions disabled may result in degradation of network performances. To avoid service degradation, it is important to properly design

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Data rate (Gb/s)

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FEC

Line coding

Tx type and launch power (dbm)

1.25

Optional RS(255, 239)

8b/10b

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PX20: OLT: [2,7] ONU: [–1,4]

10.3125

10.3125

Enabled RS(255, 223)

64b/66b

PR10: OLT: EML [1,4] ONU: DML [–1,4]

PR20: OLT: EML+AMP [5,9] ONU: DML [–1,4]

PR30: OLT: EML [2,5] ONU: HP DML [4,9]

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PRX10: OLT: EML [1,4] ONU: DML [–1,4]

PRX20: OLT: EML+AMP [5,9] ONU: DML [–1,4]

PRX30: OLT: EML [2,5] ONU: DML [.6,5.6]

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Table 1. Comparison between 1G-EPON and 10G-EPON. MAC-layer control and scheduling schemes that are aware of the disabled functions. This is the focus of this article. We first discuss the evolution from 1G-EPON to 10G-EPON. Then, we discuss the challenges in empowering optical network units (ONUs) in low-power mode. Finally, we detail our proposed control and scheduling schemes to achieve energy saving without degrading user services.

EVOLUTION FROM 1G-EPON TO 10G-EPON 10G-EPON supports both symmetric 10 Gb/s downstream and upstream, and asymmetric 10 Gb/s downstream and 1 Gb/s upstream data rates, while 1G-EPON provides only the 1 Gb/s symmetric data rate. With a focus on the physical layer, the IEEE 802.3av Task Force specifies the reconciliation sublayer (RS), symmetric and asymmetric physical coding sublayers (PCSs), physical media attachments (PMAs), and physical media-dependent (PMD) sublayers. Table 1 lists several key physical layer features of 10G-EPON [7]. Instead of using the 8B/10B line coding adopted in 1G-EPON, 10G-EPON employs 64B/66B line coding, with which the bit-to-baud overhead is reduced to as small as 3 percent. To relax the requirements for optical transceivers, Reed-Solomon code (255, 223) is chosen as the mandatory forward error correction (FEC) code in 10G-EPON to enhance the FEC gain, while Reed-Solomon code (255, 239) is specified as optional for 1G-EPON. 10G-EPON defines the PRX power budget for asymmetric-rate PHY of 10 Gb/s downstream and 1 Gb/s upstream, and the PR power budget for symmetric-rate PHY of 10 Gb/s both upstream and downstream. Each power budget further contains three power budget classes: low power budget (PR(X)10), medium power budget (PR(X)20), and high power budget (PR(X)30). PR(X)10 and PR(X)20 power budget classes are defined in 1G-EPON as well, while PR(X)30, which can support 32-split with a distance of at least 20 km, is an additional one defined in 10G-EPON. Due to limited space, we only list the transmitter (Tx) type along with its launch power of 10G-EPON in Table 1. As compared to 1G-EPON, advanced transmitters and higher launch power are employed in 10G-EPON

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to guarantee a sufficient signal-to-noise ratio (SNR) at the receiver side for accurate recovery of data with a rate of 10 Gb/s. Because of the increased launch power, the power consumption of the optical transmitter should be increased accordingly. Also, due to the mandatory FEC mechanism and increased line rate, the electronic circuit has to enable more functions and process faster than that in 1G-EPON, thus consequently incurring high power consumption and possibly larger heat dissipation. Therefore, to accommodate 10 Gb/s in the physical layer, the power consumption of the optical line terminal (OLT) and ONU may increase significantly. For the MAC layer and layers above, in order to achieve backward compatibility such that network operators are encouraged to upgrade their services, 10G-EPON keeps the EPON frame format, MAC layer, MAC control layer, and all the layers above almost unchanged from 1G-EPON. This further implies that similar network management system (NMS), PON-layer operations, administrations, and maintenance (OAM) system, and dynamic bandwidth allocation (DBA) used in 1G-EPON can be applied to 10G-EPON as well. Next, with a focus on MAC layer control and DBA, we propose a scheme to reduce energy consumption of 1G-EPON and 10G-EPON. In this article, we focus on reducing the energy consumption of ONUs.

CHALLENGES IN SAVING ENERGY OF 1G-EPON AND 10G-EPON Formerly, the sleep mode was proposed to be introduced into ONUs to save energy when ONUs are idle [8–10]. ITU-T Recommendation G. sup 45 [11] specified two energy saving modes for ONUs in GPON. One is doze mode, in which only the transmitter can be turned off when possible. Another one is cyclic sleep mode, in which both transmitter and receiver can be turned off. Since the access network traffic is rather bursty [12], ONUs may be idle for quite long periods, implying that putting idle ONUs into sleep mode is an effective way to reduce energy consumption. However, it is challenging to wake up sleep ONUs in time to avoid service disruption when downstream or upstream traffic arrives in 1GEPON and 10G-EPON.

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The major challenge lies in downstream transmission. In EPON, the downstream data traffic of all ONUs is time-division multiplexed (TDM) into a single wavelength, and is then broadcasted to all ONUs. An ONU receives all downstream packets and checks whether the packets are destined to itself. An ONU does not know when the downstream traffic arrives at the OLT and the exact time the OLT schedules its downstream traffic. Therefore, without proper sleep-aware MAC control, receivers at ONUs need to be awake all the time to avoid missing their downstream packets. To address this problem, Mandin [9] proposed to implement a three-way handshake process between OLT and ONUs before putting ONUs to sleep. Since an OLT is aware of the sleep status of ONUs, it can queue the downstream arrival traffic until the sleep ONU wakes up. However, to implement the three-way handshake process, extended multipoint control protocol (MPCP) is required to introduce new MPCP packet data units (PDUs). In addition, the negotiation process takes at least several round-trip times that further incurs large delay. Lee et al. [13] proposed to implement fixed bandwidth allocation (FBA) when the network is lightly loaded. By using FBA, the time slots allocated to each ONU in each cycle are fixed and known to the ONU, and thus ONUs can go to sleep in the time slots allocated to other ONUs. However, since traffic of an ONU changes dynamically and from cycle to cycle, FBA may result in bandwidth under- or overallocation, and consequently degrade services of ONUs to some degree. Besides the downstream scenario, an efficient sleep control mechanism should also consider upstream traffic and MPCP control message transmission. For upstream transmission, the wake-up of a sleep ONU can be triggered by the arrival of upstream traffic. However, this arrival traffic cannot be transmitted until the ONU is notified of the allocated time from the OLT. Before the OLT allocates bandwidth to an ONU, the newly awake ONU first needs to request upstream bandwidth. To realize this, some periodic time slots may need to be allocated to ONUs to enable them to access the upstream channel in time even when they are asleep. Regarding the MPCP control message transmission, to keep a watchdog timer in the OLT from expiring and deregistering the ONU, both IEEE 802.3ah and IEEE 802.3av specify that ONUs should send MPCP REPORT messages to the OLT periodically to signal bandwidth needs as well as to arm the OLT watchdog timer even when no request for bandwidth is being made. The longest interval between two reports as specified by report_timeout is set as 50 ms in both 1G-EPON and 10G-EPON. Besides, the OLT also periodically sends GATE messages to an ONU even when the ONU does not have data traffic. The longest interval between two GATE messages, specified by gate_timeout, is set as 50 ms. Therefore, to comply with MPCP, sleeping ONUs need to wake up every 50 ms to send the MPCP REPORT messages and receive the GATE messages.

UNI UNI UNI

Ethernet switch

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Figure 1. The constitution of an ONU.

SLEEP-AWARE MAC CONTROL AND SCHEDULING In this section, we discuss our proposals on saving energy in ONUs. Our basic idea is still putting ONUs into sleep mode whenever possible. Different from existing proposals, which put the whole ONU to sleep, we investigate the constitution of an ONU and put different components of an ONU to sleep under different conditions.

SLEEP STATUS OF ONUS Figure 1 illustrates the typical constitution of an ONU. The optical module consists of an optical transmitter (Tx) and an optical receiver (Rx). The electrical module mainly contains serializer/deserializer (SERDES), ONU MAC, network/packet processing engine (NPE/PPE), Ethernet switch, and user-network interfaces (UNIs). When neither upstream nor downstream traffic exists, every component in the ONU can be put to sleep. When only downstream traffic exists, the functions related to upstream transmission can be disabled. Similarly, the functions related to receiving downstream traffic can be disabled when only upstream traffic exists. Even when upstream traffic exists, the laser driver and laser diode (LD) do not need to function all the time, but only during the time slots allocated to this ONU. Thus, each component in the ONU can likely sleep, and potentially higher power savings can be achieved. By putting each component of an ONU to sleep, an ONU ends up with multiple power levels. Figure 2 shows the power levels of an ONU and the transition between different power levels. The wakeup of UNI, NPE/PPE, and switch can be triggered by the arrival of upstream traffic and the forwarding of downstream traffic from the ONU MAC [14]. They are relatively easily controlled as compared to the other components. Thus, we only focus on the ONU MAC, SERDES, Tx, and Rx. As shown in Fig. 2a, two power levels, all:awake and all:sleep, result from putting the whole ONU to sleep. In our proposal two more sleep statuses, Rx:sleep and Tx:sleep, are introduced; thus, four power levels are generated. When the ONU is in the all:awake status, if Tx does not need to work, it enters into Tx:sleep status, and further enters into all:sleep status if Rx does not need to function either. In all:sleep status, besides Rx and Tx, the ONU MAC and SERDES sleep as well. Similarly, transitions happen between the all:awake, Tx:sleep, and Rx:sleep statuses. Transitioning among these statuses should be properly designed so as to maximize energy sav-

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Power All: awake Level 2

All: awake

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Rx: sleep 7

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Figure 2. Multi-power-level ONUs.

a: If the Tx has not transmitted traffic for the time duration of idle_threshold s = 1; b: Tx enters into sleep status; sleep_time = 2s – 1*short_active + (2s–1 – 1) * idle_threshold; If sleep_time > 50 ms sleep_time = 50 ms Endif Tx wakes up after sleep time duration The ONU checks the queue length and reports the queue status If there is queued traffic Keep Tx awake s = 0; go to line a; Else s = s + 1; go to line b; Endif Endif

Algorithm 1. Decide the transition between all:awake and Tx:sleep.

ing without degrading services. We present solutions in determining the transitions under two respective scenarios: sleep for more than one DBA cycle, and sleep within one DBA cycle.

SCENARIO 1: SLEEP FOR MORE THAN ONE DBA CYCLE In this scenario the transition is decided by the incoming traffic status. Tx/Rx is put to sleep if no upstream/downstream traffic exists for some time. Whether or not downstream/upstream traffic exists can be inferred based on the information of the time allocated to ONUs and queue lengths reported from ONUs, which is known to both OLT and ONUs. If no upstream traffic arrives at an ONU, the ONU requests zero bandwidth in the MPCP REPORT message. Then, the OLT can assume that this ONU does not have upstream traffic. If no downstream traffic for an ONU arrives at the OLT, the OLT will not allocate downstream bandwidth to the ONU. Assume that, out of fairness concerns, an OLT allocates some time slots in a DBA cycle to every ONU with downstream traffic. Then, considering the uncertainty of the exact time allocated to an ONU in a DBA cycle, the ONU can infer that no downstream traffic exists if it does not receive any downstream traffic within two DBA cycles.

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The next question is to decide the transition between different statuses. In this scenario, the status Rx:sleep actually does not exist since there will still be some downstream MPCP control packets for an ONU to facilitate the upstream transmission even when no downstream data traffic exists. Hence, we next discuss the transition between all:awake and Tx:sleep, and the transition between Tx:sleep and all:sleep. Formerly, Kudo et al. [10] proposed periodic wakeup with sleep time adaptive to the arrival traffic status. We also decide the sleeping time based on traffic status. More specifically, we set the sleep time as the time duration in which traffic stops arriving. When putting Tx to sleep, for example, Algorithm 1 describes the transition between all:awake and Tx:sleep. We assume that Algorithm 1 is known to the OLT as well. Then, the OLT can accurately infer the time that Tx is asleep or awake. Let idle_threshold be the maximum time duration a transmitter stays idle before being put to sleep, short_active be the time taken for an ONU to check its queue status and send out the report, and sleep_time be the time duration each time an ONU sleeps. If the transmitter is idle for idle_threshold, Tx will be put into sleep status, and the sleep_time for the first sleep equals idle_threshold. Then, Tx wakes up to check its queue status and sends a report to the OLT, which takes short_active time duration. If there is no upstream traffic being queued, Tx will enter sleep status again. Until now, the elapsed time since the last time Tx transmitted data packets equals idle_threshold + time duration of the first sleep + short_active. So for the second sleep, the sleep time duration sleep_time is set as idle_threshold + time duration of the first sleep + short_active. According to MPCP, ONUs send MPCP REPORT messages to the OLT every 50 ms when there is no traffic. Thus, we set the upper bound of sleep_time as 50 ms to be compatible with MPCP and also to avoid introducing too much delay of the traffic which arrives during sleep mode. This process repeats until upstream traffic arrives. For the sth sleep, the sleep_time equals idle_threshold + the total time durations of the former s – 1 sleep + (s – 1)* short_active, which also equals 2 s – 1 * short_active + (2s–1 – 1) * idle_threshold. For the transition between Tx:sleep and all:sleep, the transitioning algorithm is similar to Algorithm 1 with the exception that line a should be changed to: “If the Rx has not received downstream traffic destined to the ONU for the time duration of idle_threshold.” The remaining codes are similar. Figure 3 shows an example of the sleep time control process with short_active = 2.5 ms and idle_threshold = 10 ms. Then, sleep_times of the first, second, third, and fourth sleeps are as follows: • First sleep: 10 ms • Second sleep: idle_threshold + 10 ms + short_active = 22.5 ms • Third sleep: idle_threshold + 32.5 ms + 2 * short_active = 47.5 ms • Fourth sleep: min{50 ms, idle_thresh-

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old + 80 ms + 3 * short_active} = 50 ms In deciding the sleep time, idle_threshold and short_active are two key parameters which are set as follows. idle_threshold — Setting idle_threshold needs to consider the time taken to transit between sleep and awake. Considering the transition time, the net sleep time will be reduced by the sum of the transit time from awake to sleep and the transit time from sleep to awake. Hence, idle_threshold should be set longer than the sum of two transit times in order to save energy in the first sleep. Currently, the time taken to power up the whole ONU is around 2–5 ms [8]. Hence, idle_threshold should be greater than 4 ms in this case. In addition, we assert that the upstream/downstream traffic queue is empty if no bandwidth is allocated to upstream/downstream traffic for idle_threshold. To ensure this assertion is correct, idle_threshold should be at least one DBA cycle duration, which typically extends less than 3 ms to guarantee delay performance for some delay-sensitive service. So Tx/Rx must sleep for over one DBA cycle with this scheme. short_active — During the short awake time of Tx, an ONU checks its upstream queue status and reports to the OLT. Thus, short_active should be long enough for an ONU to complete these tasks. In addition, using some upstream bandwidth for an ONU to send a report affects the upstream traffic transmission of other ONUs. In order to avoid interruption of the traffic transmission of other ONUs, we set short_active to be at least one DBA cycle duration such that an OLT can have freedom in deciding the allocated time for an ONU to send its report. For Rx, during the short awake time, the OLT begins sending the queued downstream traffic if there is any. Similar to the Tx case, short_active is set to be at least one DBA cycle to avoid interrupting services of ONUs in the Rx case.

SCENARIO 2: SLEEP WITHIN ONE DBA CYCLE In the former scenario, the sleep and awake durations of Tx and Rx are greater than one DBA cycle. In this section, we discuss the scheme of putting Tx and Rx to sleep within one DBA cycle. Consider a PON with 16 ONUs. During a DBA cycle, on average, only 1/16 of time duration is allocated to an ONU. This means that even if upstream/downstream traffic exists, Tx/Rx need only be awake for 1/16 of the time and can go to sleep for the other 15/16 of the time. Therefore, significant energy savings can be achieved. To enable an ONU to sleep and wake up within a DBA cycle, the transit time between awake and sleep should be less than half the DBA cycle duration such that the net sleep time can be greater than zero, and thus energy can be saved. Formerly, Wong et al. [15] reduced the transition time to as small as 1–10 ns by keeping some of the back-end circuits awake. Thus, with advances in speeding up transition time, it is

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1 x Sleep 3: 47.5

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Figure 3. An example of sleep time control of the transmitter. physically possible to put an ONU to sleep within one cycle to save energy. For the upstream case, waking up Tx can be triggered by ONU MAC when the allocated time comes. Tx can go to sleep after data transmission. For the downstream case, however, it is difficult to achieve since Rx does not know the time when the downstream traffic is sent and has to check every downstream packet. To address this problem, we propose the following sleepaware downstream scheduling scheme. For downstream transmission, an OLT schedules the downstream traffic of ONUs one by one, and the interval between two transmissions of an ONU is determined by the sum of the downstream traffic of all other ONUs. Again, due to the bursty nature of ONU traffic, the ONU traffic in the next cycle does not vary much from that in the current cycle. Accordingly, we can make an estimation of traffic of other ONUs and put this particular ONU to sleep for some time. More specifically, for a given ONU, denote 6 as the difference between the ending time of its last scheduling and the beginning time of its current scheduling. Then we set the rule that the OLT will not schedule this ONU’s traffic until f(6) time after the ending time of the current scheduling. As long as the ONU is aware of this rule, it can go to sleep for f(6) time durations. Figure 4 illustrates one example of putting an ONU to sleep within one DBA cycle. In this example, one OLT is connected to four ONUs, and f(6) is set as 0.8 * 6. The interval between the first two schedulings of ONU 4 is 9. Hence, the OLT will not schedule the traffic of ONU 4 until 7.2 time duration later; ONU 4 can sleep for 7.2 time duration and then wake up. However, this wakeup is an early wakeup since the actual transmission of the other ONUs takes 9.5 time durations, which is 2.3 longer than the estimation. Similarly, the duration of the second sleep is set as 7.6. However, this wakeup is a late wakeup since the actual time taken to transmit the other ONUs’ traffic is 6.5. The late wakeup incurs 1.1 idle time duration on the downstream channel. As can be seen from the example, early wakeup and late wakeup are two common phenomena of this scheme. Early wakeup implies that energy can be further saved, while late wakeup results in idle time durations, and thus possibly service degradation. From the network service providers’ perspective, avoiding late wakeup and the subsequent service degradation is more

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Figure 4. One example of putting ONUs into sleep within one DBA cycle. desirable than avoiding early wakeup. Hence, 0 < f(6) < 6 is suggested to be set. If f(6) is set as small as 0.56, on average an ONU can still sleep 15/32 of the time when a PON supports 16 ONUs and traffic of ONUs is uniformly distributed. Therefore, significant power savings can be achieved with this scheme.

CONCLUSION With the increase of line rate, energy consumption of 10G-EPON may be significantly increased as compared to that of 1G-EPON. It is important to reduce power consumption of 10G-EPON for low OPEX and environmental friendliness. In this article, with the focus on saving energy of ONUs, we have proposed to disable some functions of ONUs whenever possible, and introduced four power levels for ONUs. Then, from the perspective of MAC control and scheduling, we have investigated schemes to properly transit between power levels of ONUs. Two schemes have been proposed for two respective scenarios: sleep for over one DBA cycle, and sleep within one DBA cycle. For the former scenario, we have described the scheme of implicitly conveying sleep information between ONU and OLT, and proposed an algorithm to adapt the sleeping time to user traffic. For the latter scenario, to address the challenging issue in the downstream case, we have designed a sleep-aware downstream scheduling scheme to achieve energy saving without degrading user service.

REFERENCES [1] Y. Luo and N. Ansari, “Bandwidth Allocation for Multiservice Access on EPONs,” IEEE Commun. Mag., vol. 43, no. 2, 2005, pp. S16–S21. [2] K. Cho et al., “The Impact and Implications of the Growth in Residential User-to-User Traffic,” Proc. Conf. Apps., Tech., Architectures, Protocols for Comp. Commun., 2006. [3] R. Kubo et al., “Sleep and Adaptive Link Rate Control for Power Saving in 10G-EPON Systems,” Proc. 2009 IEEE GLOBECOM, 2009, pp. 1573–78. [4] J. Baliga et al., “Energy Consumption in Optical IP Networks,” IEEE/OSA J. Lightwave Tech., vol. 27, no. 13, 2009, pp. 2391–2403. [5] J. Baliga et al., “Energy Consumption in Access Networks,” Proc. Optical Fiber Commun. Conf., 2008. [6] C. Lange and A. Gladisch, “On the Energy Consumption of FTTH Access Networks,” Proc. Optical Fiber Commun. Conf., 2009 [7] K. Tanaka, A. Agata, and Y. Horiuchi, “IEEE 802.3av

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10G-EPON Standardization and Its Research and Development Status,” IEEE/OSA J. Lightwave Tech., vol. 28, no. 4, Feb.15, 2010, pp. 651–61. [8] S. Wong et al., “Sleep Mode for Energy Saving PONs: Advantages and Drawbacks,” IEEE GreenCom, 2009. [9] J. Mandin, “EPON Power Saving via Sleep Mode,” IEEE P802. 3av 10GEPON Task Force Meeting, 2008. [10] R. Kubo et al., “Adaptive Power Saving Mechanism for 10 Gigabit Class PON Systems,” IEICE Trans. Commun., vol. E93-B, no.2, 2010, pp. 280–88. [11] ITU-T Rec. G. sup. 45. [12] G. Kramer, B. Mukherjee, and G. Pesavento, “Ethernet PON (ePON): Design and Analysis of an Optical Access Network,” Photonic Net. Commun., vol. 3, no. 3, 2001, pp. 307–19. [13] S. Lee and A. Chen, “Design and Analysis of a Novel Energy Efficient Ethernet Passive Optical Network,” Proc. 9th Int’l. Conf. Net., 2010. [14] E. Trojer and P. Eriksson, “Power Saving Modes for GPON and VDSL,” Proc. 13th Euro. Conf. Netw. & Optical Commun., Austria, June 30–July 3, 2008. [15] S. Wong et al., “Demonstration of Energy Conserving TDM-PON with Sleep Mode ONU Using Fast Clock Recovery Circuit,” Proc. Optical Fiber Commun. Conf., 2010.

BIOGRAPHIES J INGJING Z HANG [S‘09] received a B.E. degree from Xi’an Institute of Posts and Telecommunications, China, in 2003, and an M.E. degree from Shanghai Jiao Tong University, China, in 2006, both in electrical engineering. She is working toward her Ph.D. degree in electrical engineering at the New Jersey Institute of Technology (NJIT), Newark. Her research interests include planning, capacity analysis, and resource allocation of broadband access networks, QoE provisioning in next-generation networks, and energy-efficient networking. She received the New Jersey Inventors Hall of Fame Graduate Student Award in 2010. N I R W A N A N S A R I [S‘78, M‘83, SM‘94, F‘09] (Nirwan. _____ [email protected]) received his B.S.E.E. (summa cum laude, __________ with a perfect GPA) from the New Jersey Institute of Technology (NJIT) in 1982, his M.S.E.E. degree from the University of Michigan, Ann Arbor, in 1983, and his Ph.D. degree from Purdue University, West Lafayette, Indiana, in 1988. He joined NJIT’s Department of Electrical and Computer Engineering as an assistant professor in 1988, tenured associate professor in 1993, and full professor since 1997. He has also assumed various administrative positions at NJIT. He authored Computational Intelligence for Optimization (Springer, 1997, translated into Chinese in 2000) with E.S.H. Hou, and edited Neural Networks in Telecommunications (Springer, 1994) with B. Yuhas. His current research focuses on various aspects of broadband networks and multimedia communications. He has also contributed over 350 technical papers, over one third of which were published in widely cited refereed journals/magazines. For example, one of his published works was the sixth most cited article published in IEEE Transactions on Parallel and Distributed Systems, according to the journal EIC report in February 2010. He has also guest edited a number of special issues, covering various emerging topics in communications and networking. He was visiting (chair) professor at several universities. He has served on the Editorial and Advisory Boards of eight journals, including as a Senior Technical Editor of IEEE Communications Magazine (2006–2009). He has served the IEEE in various capacities such as Chair of the IEEE North Jersey Communications Society Chapter, Chair of the IEEE North Jersey Section, member of the IEEE Region 1 Board of Governors, Chair of the IEEE Communications Society Networking Technical Committee Cluster, Chair of the IEEE Communications Society Technical Committee on Ad Hoc and Sensor Networks, and Chair/Technical Program Committee Chair of several conferences/symposia. Some of his recent recognitions include a 2007 IEEE Leadership Award from the Central Jersey/Princeton Section, the NJIT Excellence in Teaching Award in Outstanding Professional Development in 2008, a 2008 IEEE MGA Leadership Award, the 2009 NCE Excellence in Teaching Award, several best paper awards (ICNIDC 2009 and IEEE GLOBECOM 2010), a 2010 Thomas Alva Edison Patent Award, and designation as an IEEE Communications Society Distinguished Lecturer (2006–2009, two terms).

IEEE Communications Magazine • February 2011

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ADVANCES IN PASSIVE OPTICAL NETWORKS

Multirate and Multi-Quality-of-Service Passive Optical Network Based on Hybrid WDM/OCDM System Hamzeh Beyranvand and Jawad A. Salehi, Sharif University of Technology

ABSTRACT In this article we present a new scheme to support multirate and multi-quality-of-service transmission in passive optical networks based on a hybrid wavelength-division multiplexing/ optical code-division multiplexing scheme. The idea is to use multilength variable-weight optical orthogonal codes as signature sequences of a hybrid WDM/OCDM system. To provide the requested classes of service, the code weight and code length of MLVW-OOCs are designed based on the characteristics of the requested classes of service. In order to mitigate multiple access interference, we propose to utilize a multilevel signaling technique and interference remover structure based on advanced optical logic gate elements. We show that utilizing such a technique improves the QoS of the proposed scheme.

INTRODUCTION

This work was supported in part by Iran National Science Foundation (INSF).

The increasing growth of Internet Protocol (IP) and the popularity of the web are resulting in altering the traffic pattern in data networks such that voice- and text-oriented traffic have changed to data- and image-based traffic. Furthermore, the emergence of IP based multimedia applications such as VoIP, IPTV, video conferencing, and so on, diversifies data traffic having different data rate and quality of service (QoS) requirements. Therefore, designing a high-capacity network to handle diverse and bulky data traffic is an essential challenge toward next-generation data networks. Optical networks exploiting tremend