Improvement of Iterative Decoding Algorithm in the Adaptive Modulation and Coding System

In this paper, we propose and analyze an adaptive modulation system with optimal turbo coded V-BLAST (vertical-bell-lab layered space-time) technique that adopts the extrinsic information from MAP (maximum a posteriori) decoder with iterative decoding as a priori probability in two decoding procedures of V-BLAST scheme; the ordering and the slicing. The result indicates that the proposed systems achieve a better throughput performance than the conventional systems in the whole SNR range. In addition, the simulation result shows that the maximum throughput improvement in each MIMO scheme is respectively about 421 kbps, 545 kbps, and 880 kbps. It is suggested that the effect of the proposed decoding algorithm accordingly gets higher as the number of system antenna increases.