On the fading channel performance of temporal-spatial filters for CDMA

A CDMA system performance can be enhanced by interference management techniques. We consider the uplink of a CDMA system that employs two such techniques: temporal multiuser detection and spatial antenna array beam forming. Temporal-spatial MMSE type receivers with several different criteria have been previously proposed for a static channel. We consider such MMSE filters assuming a multiple time-scale fading channel model. It is shown that under the given channel conditions and system assumptions, three MMSE type receivers; the unconstrained optimum MMSE detector, the constrained optimum MMSE detector and the cascaded temporal-spatial MMSE detector are identical and the resulting combined receiver employs an MMSE multiuser detector at the output of each array element (temporal MMSE filter) followed by an MRC (spatial matched filter).