Adaptive weighted least squares CDMA multiuser detection

Abstract

Adaptive optimal CDMA multiuser detection can be performed by using a bank of MMSE filters followed by a Viterbi detector. Several characteristics of this receiver structure are investigated. It is shown that this receiver can successfully suppress narrow band interference (NBI). The effect of the MMSE filter length on MSE is investigated and it is shown that the MMSE filter length needs to be only a few symbols long. The complexity/performance tradeoff capability of the receiver is studied. It is observed that this receiver, at one end, becomes the linear MMSE receiver with lowest complexity and, at the other end, it becomes the maximum likelihood (ML) receiver with highest complexity.