Iterative Decoding Algorithm in the Adaptive Modulation and Coding System with MIMO Schemes

Sangjin RYOO
Kyunghwan LEE
Cheolwoo YOU

IEICE TRANSACTIONS on Communications   Vol.E91-B    No.4    pp.1180-1184
Publication Date: 2008/04/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e91-b.4.1180
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Wireless Communication Technologies
AMC,  Turbo Code,  V-BLAST,  MAP decoder,  iterative decoding,  

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In this paper, we propose and analyze the adaptive modulation system with optimal Turbo Coded V-BLAST (Vertical-Bell-lab Layered Space-Time) technique that adopts extrinsic information from a 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 the AMC (Adaptive Modulation and Coding) using the conventional Turbo Coded V-BLAST technique that simply combines the V-BLAST scheme with the turbo coding scheme. And we compare the proposed iterative decoding algorithm to a conventional V-BLAST decoding algorithm and a ML (Maximum Likelihood) decoding algorithm. In this analysis, the MIMO (Multiple Input Multiple Output) and the STD (Selection Transmit Diversity) schemes are assumed to be parts of the system for performance improvement. Results indicate that the proposed systems achieve better throughput performance than the conventional systems over the whole SNR (Signal to Noise Ratio) range. In terms of transmission rate performance, the suggested system is close in 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 350 kbps, 460 kbps, and 740 kbps. It is suggested that the effect of the proposed iterative decoding algorithm accordingly gets higher as the number of system antenna increases.