Improved BD Precoding Algorithms for Multi-User MIMO Systems

The Block diagonalization(BD) precoding algorithm of multi-user MIMO systems eliminates the co-channel interference(CCI),but great differences of intensity still exist in its substreams.This paper proposes a low complexity substreams selection algorithm and a power allocation scheme based on the fairness between users.The former improves the BER performance and the efficiency in power utilization with a bearable capacity loss.The later makes all the substreams have the same SNR and all the users have the same BER performance.It also reduces the computational complexity by saving the necessity in conducting numerical optimization.