Adaptive beamforming technique combined to ppSNR based switching in multi-user MIMO systems

This paper investigates adaptive Beamforming techniques used in concatenation with a ppSNR-based switching algorithm in multi-user MIMO OFDM systems. The performance´s equivalence of SM adaptive beamforming and STBC adaptive one is shown analytically and by simulation, and a complexity study is carried out and allows selecting the beamforming adapted to SM. The effect of the MIMO architecture (with or without Eigen modes selection) is also explored when the switching algorithm is combined to SM adaptive beamforming, and simulation results leads to significant improvement in terms of BER in comparison with MIMO diversity and spatial multiplexing when applied separately.