Interference Alignment-Like Behaviors of MMSE Designs for General Multiuser MIMO Systems

Interference Alignment (IA) transceiver designs are currently of great interest to the community. They are, however, limited to certain configurations. This paper seeks to show that for general multiuser MIMO systems, a) there is a relationship between MMSE designs and IA, and b) MMSE designs should be used instead of IA ones. The former is done by proving that MMSE designs naturally have IA-like behaviors. The latter is done using several arguments. One of them is based on the MIMO X network numerical results involving the generalized iterative approach (GIA) and the previously proposed MMSE-IA. In the simulation, the hybrid IA approach is clearly outperformed by the purely MMSE based GIA. The GIA is also run for the MIMO M network.