Sixth Baiona Workshop on Signal Processing in Communications David Falconer

Biography

David D. Falconer was born in Moose Jaw, Saskatchewan, Canada on August 15, 1940. He received the B.A. Sc. degree in Engineering Physics from the University of Toronto in 1962 and the S.M. and Ph.D. degrees in Electrical Engineering from M.I.T. in 1963 and 1967 respectively. After a year as a postdoctoral fellow at the Royal Institute of Technology, Stockholm, Sweden he was with Bell Laboratories, Holmdel, New Jersey from 1967 to 1980, as a member of the technical staff and later as group supervisor. During 1976-77 he was a visiting professor at Linköping University, Linköping, Sweden. Since 1980 he has been at Carleton University, Ottawa, Canada where he is a Professor in the Department of Systems and Computer Engineering. He is currently Director of the Broadband Communications and Wireless Systems
(BCWS) Centre at Carleton University. He was a consultant to Bell-Northern Research, working on ISDN access, in 1986-87 and to Codex/Motorola, working on cellular CDMA techniques, in 1990-91, during sabbaticals.

Dr. Falconer is a member of the Association of Professional Engineers of Ontario. He was awarded the Communications Society Prize Paper Award in Communications Circuits and Techniques in 1983 and again in 1986. He was a co-recipient of the IEEE Vehicular Technology Transactions best paper of the year award in 1992. He has been a Fellow of the IEEE since 1986 and a IEEE Communications Society Distinguished Lecturer since 1992.

His interests are in digital communications and communication theory, with particular application to wireless communications systems. From 1990 to 1998 he led a research project on broadband wireless communication at EHF radio frequencies, involving several universities, sponsored by CITR (Canadian Institute for Telecommunications Research), and he is still heavily involved in the project - supervising graduate student research on smart antennas for broadband wireless and EHF propagation modeling. He is also working with students on spatial-temporal processing in direct sequence CDMA receivers, and on signal processing and protocol techniques for unlicensed broadband cellular radio systems.

Talk: Frequency Domain Processing in Broadband Wireless Systems

Moderate-cost wireless communications systems offering broadband access at bit rates of 20 Mb/s and more exist now for wireless LANs, and are under intense research and standardization for outdoor fixed and mobile application environments. In these environments, non line of sight (NLOS) coverage is commonplace, causing significant multipath delay spread. The resulting intersymbol interference patterns at high bit rates may span 40 or more data symbols. Orthogonal Frequency Division Multiplexing (OFDM) is a currently popular frequency domain solution to this problem, since it uses computationally-efficient Fast Fourier Transform (FFT) operations to transmit and receive multiple narrowband non-interfering data streams over parallel subcarriers without intersymbol interference. The signal processing complexity per bit of FFT-based transmission and reception increases only logarithmically with delay spread, in contrast to the linear or quadratic trend for traditional time domain-based systems.

However the complexity advantages obtained from FFT processing are not limited to multi-carrier systems such as OFDM. The use of frequency domain receiver processing can confer the same complexity-lowering benefits on "traditional" single carrier systems. Furthermore, there are well-known advantages to single carrier systems in the form of reduced hardware costs relative to OFDM systems. Due to the latter's high transmitted peak to average power ratio and sensitivity to phase noise, OFDM systems generally require more expensive power amplifiers and synchronization components.

In this presentation we survey frequency domain processing for OFDM and single carrier broadband wireless systems, including comparisons and compatibilities, implementation and cost issues, extensions to feedback equalization, MIMO systems and overlap-save processing. We also venture some views on the role of single carrier and OFDM in B3G (beyond third
generation) wireless systems.