Joint multipath-Doppler diversity in mobile wireless communications

We introduce a new approach for achieving diversity in spread-spectrum communications over fast-fading multipath channels. The RAKE receiver used in existing systems suffers from significant performance degradation due to the rapid channel variations encountered under fast fading. We show that the Doppler spread induced by temporal channel variations in fact provides another means for diversity that can be further exploited to combat fading. We develop the concept of Doppler diversity and propose a framework that exploits joint multipath-Doppler diversity in an optimal fashion. Performance analysis shows that even the relatively small Doppler spreads encountered in practice can be leveraged into significant diversity gains via our approach. The framework is applicable in several mobile wireless multiple access systems and can provide substantial performance improvement over existing systems.

[1]  P. Bello.  Characterization of Randomly Time-Variant Linear Channels , 1963 .

[2]  Gregory W. Wornell.  Spread-response precoding for communication over fading channels , 1996, IEEE Trans. Inf. Theory.

[3]  Kaveh Pahlavan,et al.  Wireless data communications , 1994, Proc. IEEE.

[4]  J.E. Mazo,et al.  Digital communications , 1985, Proceedings of the IEEE.

[5]  Giuseppe Caire,et al.  Impact of diversity reception on fading channels with coded modulation. I. Coherent detection , 1997, IEEE Trans. Commun..

[6]  Louis L. Scharf,et al.  Low rank detectors for Gaussian random vectors , 1987, IEEE Trans. Acoust. Speech Signal Process..

[7]  W. C. Jakes,et al.  Mobile Radio Propagation , 1974 .

[8]  ChannelsAkbar M. Sayeed,et al.  MULTIUSER TIMING ACQUISITION OVER MULTIPATH FADING , 1998 .

[9]  J. Cavers.  An analysis of pilot symbol assisted modulation for Rayleigh fading channels (mobile radio) , 1991 .

[10]  A. Viterbi.  CDMA: Principles of Spread Spectrum Communication , 1995 .

[11]  Fumiyuki Adachi,et al.  Channel estimation using time multiplexed pilot symbols for coherent RAKE combining for DS-CDMA mobile radio , 1997, Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97.

[12]  Gregory W. Wornell.  Spread-signature CDMA: efficient multiuser communication in the presence of fading , 1995, IEEE Trans. Inf. Theory.

[13]  Robert Spayde Kennedy,et al.  Fading dispersive communication channels , 1969 .

[14]  Douglas L. Jones,et al.  Optimal detection using bilinear time-frequency and time-scale representations , 1995, IEEE Trans. Signal Process..

[15]  Ronald A. Iltis,et al.  A digital DS spread-spectrum receiver with joint channel and Doppler shift estimation , 1991, IEEE Trans. Commun..

[16]  Ronald A. Iltis,et al.  Joint estimation of PN code delay and multipath using the extended Kalman filter , 1990, IEEE Trans. Commun..

[17]  F. Hlawatsch,et al.  Linear and quadratic time-frequency signal representations , 1992, IEEE Signal Processing Magazine.

[18]  Srikrishna Bhashyam,et al.  Time-selective signaling and reception for multipath fading channels , 1998, Proceedings. 1998 IEEE International Symposium on Information Theory (Cat. No.98CH36252).

[19]  Akbar M. Sayeed,et al.  Communication over Multipath Fading Channels: A Time-Frequency Perspective , 1997 .

[20]  B. Sklar,et al.  Rayleigh Fading Channels in Mobile Digital Communication Systems Part II: Mitigation , 1997, IEEE Communications Magazine.

[21]  Fuyun Ling.  Coherent detection with reference-symbol based channel estimation for direct sequence CDMA uplink communications , 1993, IEEE 43rd Vehicular Technology Conference.

[22]  Ronald A. Iltis,et al.  Adaptive parameter estimation using parallel Kalman filtering for spread spectrum code and Doppler tracking , 1994, IEEE Trans. Commun..

[23]  Masao Nakagawa,et al.  Performance of orthogonal multicarrier CDMA in a multipath fading channel , 1994, IEEE Trans. Commun..

[24]  Desmond P. Taylor,et al.  Extended MLSE diversity receiver for the time- and frequency-selective channel , 1997, IEEE Trans. Commun..

[25]  Akbar M. Sayeed,et al.  Multiuser detection in fast-fading multipath environments , 1998, IEEE J. Sel. Areas Commun..

[26]  Georgios B. Giannakis,et al.  Estimation and equalization of fading channels with random coefficients , 1996, 1996 IEEE International Conference on Acoustics, Speech, and Signal Processing Conference Proceedings.

[27]  Aaas News,et al.  Book Reviews , 1893, Buffalo Medical and Surgical Journal.

[28]  Srikrishna Bhashyam,et al.  Time-selective signaling and reception for communication over multipath fading channels , 2000, IEEE Trans. Commun..

[29]  B. Sklar,et al.  Rayleigh fading channels in mobile digital communication systems Part I: Characterization , 1997, IEEE Commun. Mag..

[30]  Barry D. Van Veen.  An analysis of several partially adaptive beamformer designs , 1989, IEEE Trans. Acoust. Speech Signal Process..

[31]  J. A. Catipovic,et al.  Adaptive multiuser detection for underwater acoustical channels , 1994 .

[32]  A. Sendonaris,et al.  Multiuser detectors for fast-fading multipath channels , 1997, Conference Record of the Thirty-First Asilomar Conference on Signals, Systems and Computers (Cat. No.97CB36136).