A comparison of the MMSE detector and its BLAST versions for MIMO channels

Detection algorithms for single-user wireless communication using multiple antennas at both the transmitter and receiver in a Rayleigh (flat) fading environment are compared. The algorithms are based on the MMSE detector and its BLAST versions. Comparisons are made using bit error ratio (BER) versus signal-to-noise ratio (SNR) simulation. The system includes N transmitting antennas and M receiving antennas (N≤M). The effects of coding and error propagation on algorithm performance are investigated for BPSK and 16-QAM modulation schemes. Simulations are carried out assuming firstly no coding at the transmitter and secondly repetition coding at the transmitter (delay diversity). If no coding is implemented, the performance of the MMSE detector can be improved by implementing its D-BLAST version and further improved by implementing its V-BLAST version. If repetition coding is used, the BER versus SNR performance of the MMSE detector is at least as good as that of its BLAST versions (due to BLAST error propagation effects). In general, for both modulation and coding schemes, the best performance is achieved by using repetition coding and the MMSE detector. The effect of error propagation in the BLAST schemes on BER depends on the choice of N, M, SNR modulation scheme and coding and can be significant.