Practical low complexity linear equalization for MIMO-CDMA systems

This article first reviews recently proposed techniques for adaptive and direct linear MIMO equalization in the context of MIMO-CDMA systems and in particular with application to a MIMO-extended UMTS-FDD downlink. The focus is thereby mainly on the complexity of the algorithms. The second part of the paper proposes frequency domain (FD) MIMO equalization using the overlap/add FFT method in conjunction with two different low-complexity FD-deconvolution techniques to obtain the equalizer coefficients based on explicit channel impulse response estimates. The effects of imperfect channel estimation are discussed. An architecture for the VLSI implementation of the proposed method is suggested and an estimate of the complexity of the proposed circuit is given in the conclusions.

[1]  B. Hassibi,et al.  Adaptive equalization of multiple-input multiple-output (MIMO) frequency selective channels , 1999, Conference Record of the Thirty-Third Asilomar Conference on Signals, Systems, and Computers (Cat. No.CH37020).

[2]  Gerard J. Foschini,et al.  Layered space-time architecture for wireless communication in a fading environment when using multi-element antennas , 1996, Bell Labs Technical Journal.

[3]  John G. Proakis,et al.  Equalization and Decoding for Multiple-Input Multiple-Output Wireless Channels , 2002, EURASIP J. Adv. Signal Process..

[4]  Jonathan Ling,et al.  Performance evaluation of the VBLAST algorithm in W-CDMA systems , 2001, IEEE 54th Vehicular Technology Conference. VTC Fall 2001. Proceedings (Cat. No.01CH37211).

[5]  Sivarama Venkatesan,et al.  Chip equalisation for third generation MIMO high data rate applications , 2002, Sensor Array and Multichannel Signal Processing Workshop Proceedings, 2002.

[6]  Markus Rupp,et al.  Low complexity frequency domain equalization of MIMO channels with applications to MIMO-CDMA systems , 2003, 2003 IEEE 58th Vehicular Technology Conference. VTC 2003-Fall (IEEE Cat. No.03CH37484).

[7]  Jacob Benesty,et al.  Frequency-domain adaptive filtering revisited, generalization to the multi-channel case, and application to acoustic echo cancellation , 2000, 2000 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings (Cat. No.00CH37100).

[8]  Richard D. Wesel,et al.  Multi-input multi-output fading channel tracking and equalization using Kalman estimation , 2002, IEEE Trans. Signal Process..

[9]  Hai Huyen Dam,et al.  Frequency domain adaptive equalization for MIMO systems , 2003, 2003 IEEE 58th Vehicular Technology Conference. VTC 2003-Fall (IEEE Cat. No.03CH37484).

[10]  Markus Rupp,et al.  Performance of MIMO-extended UMTS-FDD downlink comparing space-time RAKE and linear equalizer , 2003, 2003 IEEE 58th Vehicular Technology Conference. VTC 2003-Fall (IEEE Cat. No.03CH37484).

[11]  E. Ferrara.  Fast implementations of LMS adaptive filters , 1980 .

[12]  L. Mailaender,et al.  Linear MIMO chip equalization for the CDMA downlink , 2003, 2003 4th IEEE Workshop on Signal Processing Advances in Wireless Communications - SPAWC 2003 (IEEE Cat. No.03EX689).

[13]  Dirk Dahlhaus,et al.  Joint Kalman channel estimation and equalization for the UMTS FDD downlink , 2003, 2003 IEEE 58th Vehicular Technology Conference. VTC 2003-Fall (IEEE Cat. No.03CH37484).

[14]  Yangfeng Su,et al.  On iterative solvers of the matrix equation X+A/sup T/X/sup -1/A=I , 1999, Proceedings of the 38th IEEE Conference on Decision and Control (Cat. No.99CH36304).

[15]  A. Gray,et al.  Unconstrained frequency-domain adaptive filter , 1982 .

[16]  Markus Rupp,et al.  Prototype experience for MIMO BLAST over third-generation wireless system , 2003, IEEE J. Sel. Areas Commun..