Performance 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. Also, we consider and compare The Adaptive Modulation System using conventional Turbo Coded V-BLAST technique that is simply combined V-BLAST scheme with Turbo Coding scheme and that is decoded by the ML(Maximum Likelihood) decoding algorithm. In addition, we apply MIMO (Multiple Input Multiple Output) schemes to the systems for more performance improvement. The result indicates that the proposed systems achieve a better throughput performance than the conventional systems in the whole SNR range. And in terms of the throughput performance, the suggested system is close proximity to the conventional system using the ML decoding algorithm. In addition, the simulation result shows that the maximum throughput improvement in each MIMO scheme is respectively about 421 kbps, 545 kbps, and 880 khps. It is suggested that the effect of the proposed decoding algorithm accordingly gets higher as the number of system antenna increases.