Frequency domain adaptive equalization for MIMO systems

Time domain (TD) adaptive equalization based on the modified recursive least squares (RLS) algorithm has been proposed for multiple-input multiple-output (MIMO) systems. The paper proposes frequency domain (FD) adaptive equalization to reduce the computational complexity associated with the fast converging RLS algorithm. The effect of correlation between different sub-channels of the MIMO systems is also studied. The performance in terms of bit error rate (BER) and the complexity of the FD approach is compared with that of the TD approach. The FD adaptive equalization can obtain significant computational saving over the TD approach with approximately the same BER performance even for a small number of equalizer coefficients.