Adaptive-rank receiver for space-time DS-CDMA systems

In this paper we propose a reduced rank space-time receiver for multi-user time slotted CDMA systems. The channel estimation is based on an under-parameterization of the space-time channel model. The channels for all users are estimated jointly by constraining the channel matrix of each user to be low-rank. As the rank depends on the interference level and the characteristics of the propagation environment (delay and angle spreads), the rank-order is estimated adaptively for each user according to the MDL criterion (Minimum Description Length).