Linear multiuser detection for CDMA systems with correlated spatial diversity

This contribution analyzes the behaviour of CDMA (code division multiple access) systems with correlated spatial diversity. The users transmit to one or more antenna arrays. The centralized receiver employs a linear multistage detector. We provide a unified framework for the performance analysis of any linear multiuser detector representable as a multistage Wiener filter in a large system with random spreading sequences and weak assumptions on the flat fading channel gains--the fading may be correlated and contain line-of-sight components. We show that, as the number of users and the spreading factor grow large with fixed ratio, the performance is independent of the correlation at the transmitting side but depends on the correlation at the receiver. The mathematical tools provided in this work enable also the design of low complexity multistage detectors with universal weights following the same lines as in [7].