Minimum SINR maximization for multiuser MIMO downlink with per BS power constraints

The joint cooperative processing of transmitted signal from several multiple-input multiple-output (MIMO) base station (BS) antenna heads is considered for users located within a soft handover (SHO) region. The mathematical framework for the SHO based MIMO system is derived and the joint design of linear transmit and receive beamformers in a MIMO multiuser transmission subject to per BS power constraints is considered. Solution for the maximization of the minimum weighted SINR per data stream criterion is proposed. The proposed algorithm is shown to provide very efficient solutions despite of the fact that the global optimum cannot be guaranteed due to the non-convexity of the problem. Moreover, a less complex but still efficient allocation method based on zero forcing transmission is provided for the same optimization criterion.