SISO MMSE - PIC detector in MIMO - OFDM systems

MIMO-OFDM with bit-interleaved coded modulation (BICM) is an attractive technique for wireless communications over frequency selective fading channels which has gained significant interests as a promising candidate for the 4th Generation wireless communication. The SISO MMSE-PIC based detector is proposed in this paper. The SISO MMSE-PIC detector exchanges soft information with SISO channel decoder through iterative process. For reduction complexity, the Max Log MAP approximations decoder is exploited for iterative BICM decoding of MIMO-OFDM under perfect channel knowledge. Simulation results in the IEEE 802.11 channel model show that the SISO MMSE-PIC iterative detector decoder leads to a clear improvement of the performance than the SISO ZF-PIC based detector with saturation at 4th iterations. For a large number of iterations, the performance improvement is not significant which could be investigated for practical reduction complexity considerations. Furthermore, for a 10 bit error rate BER target, the gain in the performance of the SISO MMSE-PIC is approximately about 3dB when the number of antennas is twice. The performance of the SISO MMSE-PIC under different modulation schemes for MIMO-OFDM systems shows that with lower modulation size, the method can perform better and decreases when the channel delay spreads is increased.