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GUEST EDITORIAL
TECHNOLOGIES IN MULTIHOP CELLULAR NETWORKS
Peter H. J. Chong
C
Fumiyuki Adachi
Seppo Hamalainen
ellular networks have existed for many years, and provide a wide range of services and worldwide roaming with low costs and stable service quality. Thus, this technology plays an important role in providing public mobile communication services. Next generation cellular networks are expected to provide richer and more diverse multimedia services, such as mobile Internet, video conferencing, and mobile gaming, with much higher data rates, even up to 1 Gb/s. Since the transmit power of a data link increases with the data rate when a specific link quality is maintained, providing very high data rate services in the future will require either the expenditure of high amounts of power or limiting the link to a short distance. Therefore, the current cellular network architecture may not be economically feasible to cater to the requirements of future mobile communication services. As an alternative to cellular communications, ad hoc networking is a wireless communication technology distinguished by allowing nodes to form an infrastructureless network by communicating via multihop transmissions. Hence, ad hoc networking can possibly reduce the transmit power needed to support high data rate services by reducing the communication distances. Recently, a newly evolved cellular network architecture, the multihop cellular network (MCN), which combines the characteristics of ad hoc networking with those of a cellular network, has been drawing a lot of attention from researchers. MCN incorporates the flexibility of ad hoc networking, while preserving the benefits of using an infrastructure. The salient feature of MCN is that communications are not restricted to single hop; multihop transmissions are allowed. The advantages of using MCN include capacity enhancement, coverage extension, network scalability, and power reduction. However, there are still a number of open research issues that need to be solved in order to provide efficient and effective multihop transmissions in cellular networks in the future. This feature topic covers a variety of research articles related to MCN technologies with the purpose of informing both industry and academia about this important research area. We received 48 articles for this call. All of
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them were reviewed by experts in this field, and six of them have been selected for publication. The first article, by L. Le and E. Hossain, “Multihop Cellular Networks: Potential Gains, Research Challenges and Resource Allocation Framework,” first presents an overview of several technologies for MCN including the potential gains and research challenges of each. The authors then present a resource allocation framework for out-of-band relaying in code-division multiple access (CDMA) cellular networks. The numerical results show that multihop transmission for CDMA cellular networks can provide a significant capacity gain. The second article, by B. Can et al., “Implementation Issues for OFDM-Based Multihop Cellular Networks,” discusses the implementation issues of orthogonal frequencydivision multiplexing (OFDM)-based MCN including the issues of synchronization for downlink transmissions, relaying, hardware implementation, and link layer retransmissions. A frame structure to enable adaptive relaying per subchannel is presented as a possible solution. In addition, the article proposes a novel retransmission method for MCN to improve performance in terms of cell latency, goodput, and throughput. The third article, by J. He et al., “Application of IEEE 802.16 Mesh Networks as Backhaul of Multihop Cellular Networks,” investigates the possible use of IEEE 802.16 mesh networking to provide ad hoc networking capability for cellular base stations and gateways to the Internet. The article studies several routing and scheduling algorithms for an 802.16-based MCN backhaul. Since MCN integrates various overlapping wireless technologies such as third-generation (3G) networks, WiMAX, and WiFi, it will create zones with different technological coverage combinations. The fourth article, by A. H. Zahran and B. Liang, “A Generic Framework for Mobility Modeling and Performance Analysis in NextGeneration Heterogeneous Wireless Networks,” presents a generic framework for mobility modeling to analyze the performance of heterogeneous networks with different overlapping technological zones using phase-type distributions.
IEEE Communications Magazine • September 2007
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GUEST EDITORIAL The fifth article, by P. P. Lam and C. Liew, “Nested Network Mobility on Multi-hop Cellular Network,” looks into network mobility (NEMO) based on pure IP layer technology to enable terminal mobility over the entire MCN. The article introduces a new architecture, which is based on nested NEMO and MCN, to support IP applications such as Internet access. A potential problem specific to the nested NEMO on MCN architecture is described, and a simple technique to overcome the problem is proposed. Finally, the feature topic concludes with an article by S. Pack et al., “Mobility Management in Mobile Hotspots with Heterogeneous Multihop Wireless Links.” This article studies two mobility management schemes, the NEMO basic support protocol and the Session Initiation Protocol (SIP)-based network mobility support protocol for mobile hotspots with heterogeneous multihop wireless links. The article first describes the location registration and packet delivery procedures in NEMO and SIP mobility management schemes. Then, the performance evaluation of these two mobility management schemes in terms of handoff latency is presented. In closing, we would like to thank all the authors who submitted papers to this feature topic for their valuable contributions. Most important, we would like to thank more than 100 experts who spent their precious time to complete the paper review process within a limited time. Without them, we would not be able to produce such a high-quality feature topic. Last but not least, we would like to thank the Editor-in-Chief of IEEE Communications Magazine, Dr. Tom Chen, and the magazine’s publication staff, Joseph Milizzo and Sue Lange, for the full support they have given us in the preparation of this feature topic.
BIOGRAPHIES PETER H. J. CHONG (
[email protected]) received a B.Eng. (with distinction) in electrical engineering from the Technical University of Nova Scotia, Halifax, Canada, in 1993, and M.A.Sc. and Ph.D. degrees in electrical engineering from the University of British Columbia, Vancouver, Canada, in 1996 and 2000, respectively. Between July 2000 and January 2001 he worked in the Advanced Networks Division at Agilent Technologies Canada Inc., Vancouver. From February 2001 to May 2002 he was with the Radio Communications Laboratory at Nokia Research Center, Helsinki, Finland, and was involved in research on WCDMA and standardization for HSDPA. During his stay in Finland, he taught part of a graduate course in WCDMA at Helsinki University of Technology. Since May 2002 he has been with the School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, where he is an assistant professor. He was a Technical Program Committee Chair for Mobility Conference 2005 and 2006, and a General Chair for Mobility Conference 2007. He was a Guest Editor of Journal of Internet Technology in 2006 and International Journal of Ad Hoc and Ubiquitous Computing in 2007. He serves as an Editor of Far East Journal of Electronics and Communications. His research interests are in the areas of mobile communications systems including channel assignment schemes, radio resource management and multiple access, MANET, and multihop cellular.
IEEE Communications Magazine • September 2007
FUMIYUKI ADACHI [M’79, SM’90, F’00] (
[email protected]) received B.S. and Dr. Eng. degrees in electrical engineering from Tohoku University, Sendai, Japan, in 1973 and 1984, respectively. In April 1973 he joined the Electrical Communications Laboratories of Nippon Telegraph & Telephone Corporation (now NTT) and conducted various types of research related to digital cellular mobile communications. From July 1992 to December 1999 he was with NTT Mobile Communications Network, Inc. (now NTT DoCoMo, Inc.), where he led a research group on wideband/broadband CDMA wireless access for IMT-2000 and beyond. Since January 2000 he has been with Tohoku University, Sendai, Japan, where he is a professor of electrical and communication engineering at the Graduate School of Engineering. His research interests are in CDMA wireless access techniques, equalization, transmit/receive antenna diversity, MIMO, adaptive transmission, and channel coding, with particular application to broadband wireless communications systems. From October 1984 to September 1985 he was a United Kingdom SERC Visiting Research Fellow in the Department of Electrical Engineering and Electronics at Liverpool University. He was a co-recipient of the IEEE Vehicular Technology Transactions Best Paper of the Year Award in 1980 and 1990, and also a recipient of an Avant Garde award in 2000. He is a member of the Institute of Electronics, Information and Communication Engineers of Japan (IEICE), and was a recipient of an IEICE Achievement Award in 2002, and a co-recipient of the IEICE Transactions Best Paper of the Year Award in 1996 and 1998. He was a recipient of a Thomson Scientific Research Front Award in 2004. SEPPO HÄMÄLÄINEN (
[email protected]) is research director at Nokia Siemens Networks. He received an M.Sc. degree in electrical engineering from Lappeenranta University of Technology’s Department of Information Technology in 1994 and a Ph.D. degree in electrical engineering from Jyväskylä University’s Department of Information Technology in February 2003. He joined Nokia Research Center in 1993, where he worked in different research and research management positions until the end of 2005. During 2002–2005 he led Nokia Research Center’s office in Beijing, China. At the beginning of 2006 he joined Nokia Networks, where he was director, Network Systems Research. Now he is working with Nokia Siemens Networks. His research interests lie in 3G and beyond 3G radio network performance and radio resource management issues. He has supervised several M.Sc and Lic.Sc thesises. He is author or co-author of six book chapters, three journal papers, 26 conference papers, and 16 independent patents. VICTOR C. M. LEUNG [S’75, M’89, SM’97, F’03] (
[email protected]) received a B.A.Sc. (Hons.) degree in electrical engineering from the University of British Columbia (UBC) in 1977, and was awarded the APEBC Gold Medal as the head of the graduating class in the Faculty of Applied Science. He attended graduate school at UBC on a Natural Sciences and Engineering Research Council Postgraduate Scholarship and obtained a Ph.D. degree in electrical engineering in 1981. From 1981 to 1987 he was a senior member of technical staff at MPR Teltech Ltd., specializing in the planning, design, and analysis of satellite communication systems. In 1988 he was a lecturer in the Department of Electronics at the Chinese University of Hong Kong. He returned to UBC as a faculty member in 1989, where he is a professor and holder of the TELUS Mobility Research Chair in Advanced Telecommunications Engineering in the Department of Electrical and Computer Engineering, and a member of the Institute for Computing, Information, and Cognitive Systems. His research interests are in the areas of architectural and protocol design and performance analysis for computer and telecommunication networks, with applications in satellite, mobile, personal communications, and high-speed networks. He is a voting member of ACM. He is an editor of IEEE Transactions on Wireless Communications, an associate editor of IEEE Transactions on Vehicular Technology, and an editor of International Journal of Sensor Networks. He has served on the Technical Program Committees of numerous conferences, as TPC Vice Chair of IEEE WCNC 2005, General Co-Chair of ACM/IEEE MSWiM 2005, and General Chair of QShine 2007.
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