Decorrelation Based Receive Transformation for MIMO System under Multi-User Co-Channel Interference

The MIMO system with decorrelation based receive transformation (MIMO-DRT), in which a decorrelation based transformation is employed on the received signal and is followed by a noise-limited MIMO receiver (which treats the interference plus noise as the noise uncorrelated over all receive antennas), is studied. We derive the achievable capacity of MIMO-DRT and find that it can reach the MIMO channel capacity under multi-user cochannel interference. This result is due to the fact that MIMO-DRT decorrelates the interference plus noise over all receive antennas so that the subsequent noise-limited MIMO receiver can maximize the achievable capacity. Simulation results further show that compared to the optimum noise-limited MIMO receiver and other MIMO receivers that also employ the correlations over all receive antennas, MIMO-DRT gives significant gains in the achievable capacity.