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SERIES EDITORIAL
OPTICAL ACCESS NETWORKS
Osman S. Gebizlioglu
T
Vijay Jain
he telecommunications industry has continued to focus on providing additional network capacity to meet growing needs for bandwidth in access, metro, and long-haul networks. Throughout 2012, we noted the news of shrinking global sales volume in optical communications systems and components. However, we closed the year with hopes of accelerated efforts in expanding optical access and high-capacity optical transport networks all over the globe. In our November 2012 OCS issue, we addressed high-capacity optical transport, and therefore, we thought that it would be timely to turn our attention to advances in optical access in this first OCS issue of 2013. In this issue, we have selected five contributions that address passive optical network (PON) monitoring solutions; architectural approaches for energy savings in broadband access networks; energy-efficient optical access networks; PON for mobile backhaul; and long-reach PONs. We take this opportunity to express our appreciation for the contributions to this issue. In the first contribution, entitled “Fiber Plant Manager: An OTDR- and OTM-Based PON Monitoring System,” P. J. Urban, G. Vall-llosera, E. Medeiros, and S, Dahlfort present a set of practical requirements for a successful PON monitoring approach along with an overview of published proposals that have appeared in the literature. PON deployments require monitoring solutions that reduce the operators’ operational expenditures (OPEX). In order to achieve such OPEX reductions, monitoring systems with high reliability and accuracy should support fault detection, identification, and localization in deployments involving various fiber access topologies. They also present a method to monitor power splitter- and wavelength splitter-based PON through combined techniques of optical time domain reflectometry (OTDR) and optical transceiver monitoring (OTM). The method involves approaches that do not interfere with data traffic flow and requires no additional hardware or software functionality at the optical network terminal (ONT) side. In the second contribution, entitled “Saving Energy in Long-Reach Broadband Access Networks: Architectural Approaches,” L. Shi, P. Chowdhury, and B. Mukherjee present an analysis focused on energy conservation and reach-extension technologies for broadband access networks. They discuss several broadband access network architectural enhancements to enable energy conservation in long-reach broadband access networks using methods that may involve such techniques as turning off idle transceivers and other network elements, shedding transmission speed, and adaptive self-reconfiguration based on current traffic characteristics. In the third contribution, entitled “Energy Efficient Optical
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John Spencer
Access Networks: Issues and Technologies,” J. Kani, S. Shimazu, N. Yoshimoto, and H. Hadama present a discussion of issues and technologies for the next generation energy-efficient optical access networks with their focus on mid-term upgrades and longterm evolution. In order to reduce the total power consumption in the mid-term upgrade to 10-Gigabit access, it is necessary to optimize the network configuration as well as the usage of various technologies while avoiding any service degradation in the next generation broadband services. In the long-term evolution, wavelength routing will play a key role by drastically decreasing the total power consumption of the access network. In the fourth contribution, entitled ”Exploiting PONs for Mobile Backhaul,” T. Orphanoudakis, E. Kosmatos, J. Angelopoulos, and A. Stavdas present the results of their investigation on the use of PONs for mobile backhaul and propose a resource allocation framework building on the efficiency of PONs to share resources and dynamic bandwidth allocation in real time to enhance efficiency by improved statistical multiplexing. The growing worldwide popularity of mobile data services requires a rapid network capacity growth not only on the air interface to the end user, but also on the backhaul network interface. In the case of the backhaul network, the capacity growth is of critical importance as it impacts the mobile operator business model, affecting capital investment, operational expenses, service deployment, and customer experience. Fiber infrastructure is inevitably the only long-term solution, and the deployment of PONs presents an opportunity for a cost-effective, scalable, and future-proof solution. The main objective of this work is to use existing standardized technologies, and provide design and deployment guidelines regarding the PON medium access control (MAC) operation enabling a gradual and future-safe infrastructure upgrade of mobile backhaul networks. In the fifth contribution, entitled “Efficient Inter-Thread Scheduling Scheme for Long-Reach Passive Optical Networks,” J. Ahmed, J. Chen, B. Chen, L. Wosinska, and B. Mukherjee address current trends toward extending the reach of PON to cover large geographical areas in order to achieve central office (CO) consolidation with resultant OPEX savings. However, this reach extension necessitates the design of efficient dynamic bandwidth allocation (DBA) schemes in order to mitigate performance degradation caused by the increased propagation delay in LR-PON. Thus, they review different inter-thread scheduling schemes for LR-PON and propose a novel approach by integrating the key ideas of the existing ones that include a multi-thread-based DBA scheme where several bandwidth allocation processes are performed in paral-
IEEE Communications Magazine • February 2013
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SERIES EDITORIAL lel. They report that without proper communication between the overlapped threads, the multi-thread DBA approach may result in a loss of efficiency when compared to the conventional single-thread algorithms. Simulations conducted confirm that the proposed scheme can significantly improve DBA performance for LR-PON under a variety of scenarios with consideration of different values of network load and reach. In this first OCS issue of 2013, we wish all IEEE Communications Society members and our readers a New Year of Health, Happiness, and Success. We look forward to your continued support of the OCS and your contributions as authors and/or reviewers.
BIOGRAPHIES OSMAN S. GEBIZLIOGLU [SM] (
[email protected]) joined Huawei Technologies USA as a principal consultant for optical distribution network (ODN) technology research in February 2011. From 1987 when he joined Bellcore until his departure from Telcordia Technologies at the end of January 2011, he was involved with the development of performance and reliability assurance requirements for optical communications components. In addition to his work to support the implementation of optical communications technologies in major service provider networks, he has been involved in failure analysis and reliability assurance efforts on aerospace and defense communications networks. He holds B.Sc. and M.Sc. degrees in chemical engineering (Middle East Technical University, Ankara, Turkey), and a Ph.D in chemical engineering and polymer materials science and engineering (Princeton University, New Jersey). Before joining Bellcore in 1987, he held Monsanto and ExxonMobil postdoctoral fellowships and research scientist appointments in mechanical engineering (Mechanics of Materials Division), chemical engineering (Microstructural Engineering Division), and the Center for Materials Science & Engineering at Massachusetts Institute of Technology, Cambridge. He has been an active member of the American Chemical Society, Materials Research Society, SPIE — International Society for Optical Engineering, Optical Society of America, IEEE Photonics Society, and IEEE Communications Society. He holds five U.S. patents and chaired the Telecommunications
Industry Association TR-42.13 Subcommittee on Passive Optical Devices and Fiber Optic Metrology. He served as co-Series Editor of the IEEE Communications Magazine Optical Communications Series (2009–2012), and he is now serving the IEEE Communications Society in his new capacity as Associate Editor-in-Chief since January 1, 2013. VIJAY JAIN serves as chief technology officer in Sterlite Network Ltd. based in Mumbai, India. He held the position of general manager in Bharti Airtel prior to joining Sterlite. He was Fiber Optic Components Independent Test Laboratories program manager at Verizon to support Verizon’s FTTP initiative before his move to Bharti Airtel. He has over 15 years of experience in the telecom industry, and has worked in Canada, the United States, and India. He held management positions in telecom equipment manufacturers and product test laboratories prior to joining Verizon. During the last 15 years, he has worked in engineering, R&D planning, and strategic business development roles. His achievements include designing and testing GSM/CDMA-based wireless antenna, DSP-based VLSI chips, NMS for optical and wireless technologies, fiber optic components, and high-speed transport systems. He holds Master’s degrees, one in telecom engineering specializing in wireless technology from the Indian Institute of Technology and the other in DSP technology from Concordia University in Canada. JOHN SPENCER [SM] (
[email protected]) is a telecom industry veteran with over 37 years’ experience. He worked 29 years with BellSouth, 14 of those years as a member of technical staff in the Science & Technology Department. During that time he was involved in the introduction of SONET and erbium doped fiber amplifiers, and had a team leader role for the introduction of DWDM technology in the BellSouth network. He worked four years as regional director of product marketing engineering for Mahi Networks, Petaluma, California. He is currently business and technology strategist for Optelian Access Networks, where he manages industry and customer direction to Optelian’s product line as well as taking a key role in Optelian’s AT&T account management. He was Conference Co-Chairman for NFOEC in 1991 and 1998. He has served on the NFOEC Technical Program Committee for 10 years. He served as Secretary and Chairman of ANSI accredited committee T1X1, Digital Hierarchy and Synchronization, which developed the standards for SONET. He is a graduate of Georgia Institute of Technology (B.E.E.) and is a registered Professional Engineer (PE) in the State of Alabama. He currently serves on the NFOEC/OFC Technical Program Committee.
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IEEE Communications Magazine • February 2013
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