Spatial-temporal CDMA receiver structures for Rayleigh fading channels
Ruifeng Wang, Steven D. Blostein · 2003
We investigate multi-user signal detection with a base-station antenna array for synchronous CDMA Rayleigh fading uplink channels. We have developed a discrete-time model that enables the formulation of a spatial-temporal decorrelating detector using the maximum-likelihood criterion. The detector is shown to be near-far resistant. We implement the spatial-temporal decorrelating receiver iteratively by applying either the expectation-maximization (EM) algorithm or the space alternating generalized expectation-maximization (SAGE) algorithm. Out of the two receiver structures obtained, the SAGE-based decorrelating receiver outperforms the EM-based decorrelating receiver and converges to the performance of the spatial-temporal decorrelating receiver with known channel parameters.