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Tutorial 1- Broadband Wireless Access using TD-CDMA Technology for Cellular and Ad Hoc Systems

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Riaz Esmailzadeh, Keio University, Yokohama

Harald Haas, International University of Bremen

This tutorial will provide an in-depth analysis of the Time Division Duplex (TDD) mode of CDMA (Code Division Multiple Access) communications as it applies to the 3rd and 4th generation of mobile communications systems. It deals with both TD-CDMA, or UTRATDD (UMTS Terrestrial Radio Access), and TD-SCDMA standards and discusses the associated public and ad-hoc network topologies for next generation systems. The tutorial provides a detailed state of the art analysis, including the implementation and rollout issues, and how the TD-CDMA business and technology is developing.

Although considered a complimentary technology to the Frequency Division Duplex (FDD) mode in the 3G standards, TDD systems are emerging as equal, if not the dominant, mode of the future mobile communication services (including 3G services).
They are the front-runner to become the major duplex technology in 4G systems as flexible operation, asymmetric capacity requirements of 4G services, as well as unpaired frequency allocation and the lack of a guard radio frequency band gives them a significant advantage over the FDD mode - especially for asymmetric high data rate transmission. In addition to these advantages, the channel reciprocity characteristic of TDD transmission facilitates specific techniques, which enable TDD systems to transmit at higher rates and support higher system capacity. In addition, new communication modes such as ad hoc, relaying or multi-hop will play a significant role in future wireless communications due to the significantly reduced coverage for high data-rate transmissions. It will be demonstrated the TDD technology is the most appropriate duplexing method to enable the new communications modes. We complete the tutorial with a study of cost vs. benefits of TD-CDMA as compared with some other broadband wireless systems.

The disadvantageous of the TDD mode such as the need for synchronisation will also be discussed and solutions will be provided.

Biography : Dr. Riaz Esmailzadeh
Dr. Riaz Esmailzadeh received his PhD in Electrical Engineering from Keio University, Japan, in 1994, and MBA from IMD, Switzerland, in 2002. He has over 17 years of work experience in various capacities related to telecommunications research, development and management. Riaz worked as a research engineer in Telstra, Australia, continued at the central research laboratories of Hitachi in Tokyo, and after working at Ericsson in Sweden, founded the research unit at Nippon Ericsson. He then co-founded and was the CTO at Genista Corporation, a telecom software company headquartered in Tokyo. Since September 2002, he is an Associate Professor at the Information and Computer Science
Department of Keio University, Yokohama, Japan. He is a co-author of "TDD-CDMA for Wireless Communications," published by Artech House in October 2002. He has been an author of more than 70 technical paper in journals and international conferences, and more than 50 patent applications, 16 of which have so far been granted.

Biography : Dr. Harald Haas
Dr. Harald Haas received the Ph.D form Edinburgh University (Scotland / UK) in 2001. From 1998 until 2001 he was research associate and Nokia consultant at Edinburgh University where he conducted research on interference, coverage and capacity issues and dynamic channel assignment (DCA) algorithms for TDD based 3G cellular systems. Dr. Haas received the best paper award at the International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC) in 1999 and was awarded the Honorary Fellowship of Edinburgh University in 2001. In February 2001, Dr. Haas joined Siemens AG, Information and Communication Mobile Networks, where he was the project
manager of a joint research project involving Chinese and German universities. He conducted and managed research on potential 4G technologies such as multi-carrier transmission, link adaptation, ad-hoc communication, MIMO techniques and DCA algorithms for TDD based cellular systems. From September 2002 until now, Dr. Haas is Associate Professor at the International University Bremen (IUB), Germany. His research interests are geared towards joint optimisation of physical layer and system layer techniques for TDD-based enhanced-3G and 4G systems. Dr. Haas holds several patents and has published numerous peer-reviewed conference and journal papers.