Research on Hybrid-ARQ Chase Combining Algorithms in ZF-SIC V-BLAST

In the conventional zero-forcing successive interference cancellation (ZF-SIC) detection algorithm of vertical Bell-Labs layered space-time (V-BLAST) architecture, the detection algorithm does not attempt to eliminate the effect of the error propagation, which is significantly deleterious to hybrid automatic repeat request (H-ARQ) scheme using bit-level Chase combining. Based on two ordering approaches respectively, we propose two novel H-ARQ bit-level Chase combining algorithms in this paper, which employ a new log-likelihood ratio (LLR) calculation algorithm to minimize the effect of the error propagation. Additionally, we bring forward a new pairwise LLR combining technique to enhance the reliability of ordering stage considerably. Through simulation results, it is shown that the new proposed algorithms outperform the conventional ones in system performance.