Abstract
We propose a joint transmit and receive optimization scheme for the multi-input multi-output (MIMO) spatial multiplexing system (also known as BLAST) in a narrowband wireless channel. The optimum solution is found using the minimum mean square error criterion subject to average transmitter power constraint. The transmit and receive filters are shown to decouple the MIMO channel into parallel sub-chanhels. The optimum power allocation policy on these sub-channels is derived.