Performance of low-complexity MMSE beamforming for WLAN systems

In this paper the use of adaptive antenna arrays for OFDM-based WLAN systems in indoor wireless environment is investigated. We present the performance of a new proposed low-complexity MMSE beamforming for OFDM systems in a frequency selective Rayleigh fading channel. The proposed MMSE beamforming algorithm is based upon hybrid frequency-time domain processing, where the dominant computation of the beamforming algorithm is carried out in the time domain while the minor part of the beamforming computation is done in the frequency domain. This approach provides significant computational complexity reduction over the conventional frequency domain beamforming for OFDM-based systems. We evaluate the system performance of the hybrid frequency-time domain beamforming algorithms through the use of computer simulation. The preliminary simulation results show that the proposed hybrid frequency-time domain beamforming outperforms time domain beamforming. Furthermore it provides acceptable system performance with significant computation reduction as compared to the conventional frequency domain beamforming.