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Radio Resource Management in OFDMA-Based Cellular Relay Networks Radio Resource Management in OFDMA-based Cellular Relay Networks Mohamed Salem, B.Sc, M.Sc. A thesis submitted to The Faculty of Graduate and Postdoctoral Affairs in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical Engineering Ottawa-Carleton Institute for Electrical and Computer Engineering Department of Systems and Computer Engineering Carleton University, Ottawa, Ontario, Canada ©2011 Mohamed Salem Library and Archives Bibliotheque et 1*1 Canada Archives Canada Published Heritage Direction du Branch Patrimoine de I'edition 395 Wellington Street 395, rue Wellington Ottawa ON K1A 0N4 Ottawa ON K1A 0N4 Canada Canada Your file Votre reference ISBN: 978-0-494-79636-8 Our file Notre reference ISBN: 978-0-494-79636-8 NOTICE: AVIS: The author has granted a non­ L'auteur a accorde une licence non exclusive exclusive license allowing Library and permettant a la Bibliotheque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par I'lnternet, pr§ter, telecommunication or on the Internet, distribuer et vendre des theses partout dans le loan, distribute and sell theses monde, a des fins commerciales ou autres, sur worldwide, for commercial or non­ support microforme, papier, electronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriete du droit d'auteur ownership and moral rights in this et des droits moraux qui protege cette these. Ni thesis. Neither the thesis nor la these ni des extraits substantiels de celle-ci substantial extracts from it may be ne doivent etre imprimes ou autrement printed or otherwise reproduced reproduits sans son autorisation. without the author's permission. In compliance with the Canadian Conformement a la loi canadienne sur la Privacy Act some supporting forms protection de la vie privee, quelques may have been removed from this formulaires secondaires ont ete enleves de thesis. cette these. While these forms may be included Bien que ces formulaires aient inclus dans in the document page count, their la pagination, il n'y aura aucun contenu removal does not represent any loss manquant. of content from the thesis. 1*1 Canada Abstract The main objective of next-generation wireless networks is to accommodate the in­ creasing user demand and to achieve a ubiquitous high-data-rate coverage so that mobile broadband services comparable to those of the wirelines are realized in a cost- efficient manner. This ambitious objective however faces several technical challenges in the conventional cellular architecture, e.g., the large pathloss. Wireless multihop relaying is therefore among the envisioned solutions; for that relays- with much less functionality and cost than base stations- can extend coverage, overcome shadowing through routing, and/or improve detection in a cooperative manner. Hence, a future network comprising various forms of dedicated wireless relays is envisaged in many wireless standardization bodies and forums which have adopted orthogonal frequency division multiple access (OFDMA) as the prospective air interface. The synergy of multihop relaying and OFDMA techniques offers a very rich set of opportunities but renders an unsuitable environment for static resource planning. This is due to the increased system dynamics, the portion of resources invested in operating the wireless relays, and the co-channel interference associated with the inevitable aggressive reuse of the scarce licensed spectrum. Therefore, intelligent radio resource management (RRM) schemes are required to combat the interference and to operate the relays in a dynamic and opportunistic manner. It is not immediately clear though how to perform RRM in such a complex environment. As such, RRM could be the main obstacle confronting the deployment and operation of future networks. iii On these grounds, our objective is to devise intelligent RRM schemes that dy­ namically optimize the resource allocation in future networks in multiple dimensions; frequency, time, space, power, and relay route, so that bandwidth is efficiently uti­ lized while a reliable and ubiquitous service is achieved regardless of users' locations and channel conditions. Towards that end, mathematical optimization and dynamic programming tools are employed along with novel opportunistic medium access tech­ niques, in a centralized as well as a distributed manner. Various forms of relays of different characteristics and functionalities, such as the fixed and nomadic relays, are incorporated. In addition, algorithms with low computational complexity and signaling overhead are devised for practical implementation. IV Acknowledgement In the name of God the Most Gracious, the Most Merciful. To Him we belong and all the praise and thanks are due. By only His will our efforts could ever be fruitful and our plans could ever be seen through. No matter how much knowledge we acquire, He remains the utmost knowing and before His name, none of the following deservings may show. My deep and sincere thanks, gratitude and respect are due to my academic super­ visor and research mentor, Prof. Halim Yamkomeroglu. No doubt, I would attribute the success of this program to his on-going guidance and phenomenal mentorship that was never limited to the highly professional academic and technical supervision. I must also acknowledge his persistent encouragement and inspiring enthusiasm to conduct high quality research publishable in the first tier journals and flagship inter­ national conferences. He has been more of a friend or an older brother to me than a supervisor. In a nutshell, Prof. Yamkomeroglu has made the usually cumbersome and stressful PhD course of study an enjoyable and unforgettable experience for me. My appreciation and gratitude are due as well to my thesis co-supervisor, Prof. David Falconer whose invaluable comments and professional insights have substan­ tially enhanced the quality of this work, not to mention his persistent and strong support in grant and award applications throughout the program. I would like also to thank my project manager, my co-author, and my dear friend, Dr. Abdulkareem Adinoyi, for all his sincere efforts, sleepless nights and diligent work v he has put into that project to make it such a success. He has indeed provided me with an ideal research environment that was full of appreciation, brotherhood, and productive teamwork. Sincere thanks to all of my colleagues and fellow researchers who helped me see this dream coming true, especially Mahmudur Rahman, whose technical tips and experience have expedited the warming phase of my research; and also Sebastian Szyszkowicz who have kindly helped me shape this thesis into its current format. I would like also to thank our industrial collaborator, Samsung Electronics, SAIT, Korea, for funding this program, providing enlightening discussions, and filing three patents out of this work. On the personal side, special thanks and gratitude to my beloved parents for their continuous support and encouragement throughout my career. I just can not thank them enough for every single moment and effort they invested on my path to earn this degree. May the success of this program be the sweet fruit of their long-term strive. I would like also to express my appreciation and gratefulness to my beloved wife for her tireless support, understanding, patience, and countless sacrifices since I started this program. There are no words indeed that can be said in return to her loving care. Although he is only one year old, I wouldn't deny as well the great influence my little son had on my enthusiasm and motivation to attain such an honor that would make him proud once he is old enough to read and comprehend these lines. Last but not least, I would like to thank my sister and my brother for their warm encouragement and moral support. VI Contents Abstract iii Acknowledgement v Contents vii List of Figures xii List of Tables xviii Nomenclature xix 1 Introduction 1 1.1 The RRM Problem Statement 2 1.2 Publications, Patent filings, and Technical Reports 5 2 Overview on RRM in OFDMA Relay Networks 10 2.1 Activities on Relay-based Architecture among Standardization Bodies, Forums, and Consortiums 11 2.2 Some Basic RRM Tools 13 2.2.1 Scheduling 13 2.2.2 Routing 14 2.2.3 Link Adaptation: Adaptive Modulation and Coding 15 vii 2.2.4 Power Control 15 2.2.5 Cooperative Relaying in OFDMA Networks 16 2.3 Earlier RRM Research in Relay Networks 18 2.3.1 Relaying in Downlink Multicellular Networks 18 2.3.2 Relaying in Uplink Multicellular Networks 21 2.4 RRM in OFDMA Fixed-Relay Networks 24 2.4.1 Centralized RRM Schemes in Single-cell OFDMA Relay Networks 24 2.4.2 Centralized RRM Schemes in Multi-cell OFDMA Relay Networks 30 2.4.3 Distributed RRM Schemes in OFDMA Relay Networks .... 33 2.5 RRM Opportunities and Challenges in OFDMA Cellular Relay Networks 35 2.5.1 Migration from Conventional Cellular to Relay-Enhanced ... 35 2.5.1.1 Centralized or Distributed? 35 2.5.1.2 Cell-load Balancing 37 2.5.1.3 Various Forms of Wireless Relays of Different func­ tionalities 37 2.5.1.4 Relay Selection or In-Cell Routing 39 2.5.1.5 CAC and Handover for Network-Load Balancing via Inter-Cell Routing 40 2.5.2 Co-Channel Interference in OFDMA Cellular Relay Networks 41 2.5.3 Restating the Strategy for Improving the Goodput Efficiency
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