Downlink precoding for multiuser spatial multiplexing MIMO system using linear receiver

In this paper, we propose a novel unitary downlink precoding design scheme for multiuser (MU) spatial multiplexing (SM) multiple-input multiple-output (MIMO) systems. With the perfect channel state information (p-CSI) available at the transmitter and the linear decoder at the receiver, we construct the cost function based on the minimum average probability of vector symbol error (APVSE) and give the design method of the precoding matrices. Our proposed precoding matrices can completely eliminate co-channel interference (CCI) for each user at the transmitter, and each terminal user will eventually observe an interference-free single-user (SU) channel, thus simplify the decoding of each terminal user. Finally, we derive the upper bound APVSEs of several schemes for performance comparison and the latter simulation results have shown that our proposed downlink precoding for MU SM MIMO system obtains the almost same performance as the SU precoding system.