Distributed power control and beamforming on MIMO interference channels

This paper considers the so-called Multiple-Input-Multiple-Output interference channel (MIMO-IC). We address the design of precoding (i.e. beamforming) vectors and power control at each data stream with the aim of striking a compromise between beamforming gain at the intended receiver (Egoism) and the mitigation of interference created towards other receivers (Altruism). Combining egoistic and altruistic beamforming has been shown previously to be instrumental to optimizing the rates in a Multiple-Input-Single-Output (MISO) interference channel and MIMO-IC. Here we extend these concepts to multi-stream scenarios and further improve the rate performance by allowing power control which is not addressed in previous interference alignment related works. The key idea behind power control in interference coordination schemes is that it can help restore feasibility conditions in the high SNR regime, thus avoiding a saturation of the sum rate. Our analysis and simulations attest improvement in terms of complexity and performance.