Generalized Orthogonal Sequences and Their Applications in MIMO Channel Estimation

by Professor Pingzhi Fan, SMIEEE, PhD(UK), Chair of the IEEE China VT Chapter, Institute of Mobile Communications, Southwest Jiaotong University, Chengdu, China

 :  06 Jun 2005 (Mon)
 :  3:00pm - 4:30pm
Venue  :  Room 2464, 2/F (Lifts 25-26), HKUST

Efficient channel estimation plays a key role in multiple-input multiple-output (MIMO) wireless communication systems as the performance of space-time decoders depends on how accurate the channel knowledge is. To minimize estimation errors due to interference, for a single tap coefficient discrete channel model with identically independent additive Gaussian noises, orthogonal sequences such as Walsh sequences can be simultaneously applied to transmitter antennas. In the case of multi-path channel, the channel for each pair of transmitting and receiving antennas should be modeled by several taps, which will introduce multi-path interference, thus destroying the orthogonality between Walsh sequences. In such case, ideal training sequences having both zero cross-correlation function and impulsive autocorrelation function should be used. Unfortunately, according to Welch and other bounds, such set of ideal training sequences does not exist. Instead, optimal MIMO channel estimation can be achieved if the training sequence used in each antenna is not only orthogonal to its shifts within Z taps but also orthogonal to the training sequences in other antennas with shifts within Z taps. In this talk, concepts and constructions of generalized orthogonal (GO) sequences, or zero correlation zone (ZCZ) sequences, are discussed. It is shown that the use of the GO sequences can effectively reduce the mutual interference among different transmitting antennas, compared with the conventional orthogonal and pseudorandom sequences. By considering a general multi-path MIMO channel model, a closed-form estimation variance, together with the performance of the least squares (LS) and scaled LS (SLS) approaches, is presented for MIMO channel estimation employing GO training sequences. Besides, implicit channel estimation using GO training sequences is also investigated


Pingzhi Fan, SMIEEE, M.Sc (China), Ph.D (UK). He is currently a professor and director of the Institute of Mobile Communications, Southwest Jiaotong University, PRC, chairman of the IEEE China VT Chapter. His research interests include CDMA theory and technology, information theory & coding, sequence design & applications, radio resource management, cellular radio positioning, etc.

He is a guest editor, associate editor or editorial member of a number of academic journals, including International Journal of High Performance Computing and Networking (Inderscience, USA), Journal of Wireless Communications and Mobile Computing(John Wiley & Sons. Ltd., USA), Parallel and Distributed Computing: Applications and Technologies (volume LNCS-3320, Springer-Verlag, 2004, Berlin), IEICE Transactions on Information and Systems (IEICE, Japan), IEICE Transactions on Fundamentals (IEICE, Japan), Chinese Journal of Electronics, Journal of Radio Science, Journal of Circuit and System, Journal of Transport Engineering and Information, Computer Applications, Railway Signalling & Communication Engineering, Computer Applications in Railway, etc. He is also a regular reviewers of a number of academic journals and international conferences, such as transactions and journals of IEEE and IEICE, journals of IEE, CIE, CIC etc. He serves as the general chair or program chair of SETA'06, WSN'05, IWSDA'05, WICSP'04, PDCAT'03 and IWSDA'01, and a co-chair, track chair, or PC member of a number of international conferences, including, VTC Fall'05, ICCCAS'05, WSN'05, VTC'03, MAIM'03, ISCTA'03, PDCAT'02, ICCCAS'02, DSPCS^Ò00, IMA-CC'98, etc. He has published 7 books and over 200 research works, including 4 books published in English by John Wiley (1996),SWJTU Press (2001), IEEE Press (2003), Springer-Verlag (2004) respectively, over 100 journal papers and about 100 referred conference papers. The journal papers include those published in IEEE Trans on IT, IEEE Trans on PDS, IEEE Trans on Com, IEEE Trans. on VT, IEEE Trans. on Computer, IEEE Communication Letters, IEICE Trans. on Fund., IEICE Trans. On Info & Syst, IEE Electronic Letters, IEE Proc. on Communications,, Applied Signal Processing, Science in China, Acta Electronica Sinica, Journal of Communications, Journal of Railway, Journal of Circuit and System, Journal of Mobile Communications, Railway Communications and Signalling, etc. He is the inventor of 15 patents. Recent and current on-going research projects led by Dr Fan are funded by Royal Society (UK), DAAD (Germany), MEXT (Japan), JSPS (Japan), RGC (Hong Kong), IITA/KOSEF (South Korea), NSFC(China), National 863 project (MoST), University Doctorial Research Foundation (MoE), industrial companies and other sources. He has been a visiting professor with many academic institutions in the world, such as, Leeds University, UK; Georgia State University, USA; National Chonbuk University, South Korea; Tsukuba University, Japan; Mikkeli Polytechnic, Finland; FernUniversity, Germany; University of Science and Technology, Hong Kong; Shanghai Jiaotong University, China, UESTC, China, etc.


*** All are Welcome ***