Abstract—Bit interleaved coded modulation (BICM)schemes have been shown to increase the diversity order.This paper studies the extension of such schemes with iterativedemodulation and decoding (ID) using error correctingcodes coupled with rotated MPSK signal constellationswith different symbol mappings and signal space diversity(SSD). Using extrinsic information transfer (EXIT) charts,an analysis of the impact of the rotation angle on theperformance of the system is presented. It is shown that fora given signal constellation, labeling, error correcting codeand Eb=N0-value, where conventional BICM-ID system’sdecoding trajectory gets stuck in a Rayleigh fading channel,SSD with a well considered choice of the rotation angleallows for the convergence of iterative demodulation anddecoding. Furthermore, it is shown that the proposed systemcan lead to a significant performance gain over BICM-ID.The optimal choice of the rotation angle for the coded systemis shown to be dependent upon the signal labeling and theerror correcting code being employed. Factors (degrees offreedom) that can effect the convergence behavior of theiterative demodulation and decoding of the proposed systemare identified and their effect is analyzed.
 
Index Terms—Channel coding, modulation, iterative demodulationand decoding, diversity, and EXIT chart analysis.

Cite: Nauman F. Kiyani and Jos H. Weber, "EXIT Chart Analysis of Iterative Demodulation and Decoding of MPSK Constellations with Signal Space Diversity," Journal of Communications, vol. 3, no.3, July, pp.43-50, 2008.