Approaching ergodic capacity in time varying MIMO V-BLAST channels

In this paper, a new low complexity rate quantization scheme is proposed for MIMO V-BLAST systems in time varying channels, the adaptive modulation issue for MIMO V-BLAST systems in time varying channels is investigated and a low complexity rate quantization scheme is proposed. In V-BLAST systems, the optimal adaptation modulation scheme is difficult to find due to optimum successive decoding at the receiver. Without any exhaustive numerical search, the proposed modified successive quantization with power control (MSQPC) with square QAM constellations of 5 rate levels is shown to significantly improve the spectral efficiency. The results show that this latter with MSQPC is about 1.5 dB greater than other recently proposed rate quantization for V-BLAST