Abdulrauf Hafeez

Abdulrauf Hafeez

EECS Department

University of Michigan

Thursday, February 18
4:30 - 5:30 PM
Room 1001 EECS

Trellis based algorithms for equalization and multiuser detection


Maximum-likelihood sequence estimation (MLSE) is an optimum detection technique for channels with memory and additive noise. An attractive low-complexity alternative to MLSE is known as decision feedback sequence estimation (DFSE). DFSE is a reduced trellis search algorithm which finds applications in equalization of inter-symbol interference, detection of partial response signals, trellis-coded modulation and multiuser detection. In this talk, we examine the role of the receive filter and the branch metric in DFSE receivers. An analysis of the DFSE receiver indicates that a proper combination of the receive filter and the branch metric is necessary to avoid bias (untreated interference components) in the receiver. We show that the noise-whitening filter DFSE receiver is an optimum unbiased receiver in the sense that it maximizes the error distance. We obtain a novel DFSE receiver structure which is suitable for multiuser detection in DS-CDMA systems. Upper bounds on the symbol error probability of the various DFSE receivers are obtained and simulation and analytical results are presented for several examples.

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