Iterative Demodulation and Decoding for Rotated MPSK Constellations with Convolutional Coding and Signal Space Diversity

Abstract

Signal space diversity (SSD) with the rotation of the signal constellation using multi-level modulation schemes is known to provide good performance gains over fading channels. This paper studies the extension of such schemes with iterative demodulation and decoding using convolutional codes for MPSK signal constellations with different symbol mappings. It is shown that for a specific signal constellation and labeling using SSD on a Rayleigh fading channel, a well considered choice of the rotation angle leads to a significant gain over conventional bit interleaved coded modulation with iterative decoding (BICM-ID). Furthermore, the optimum rotation angle for the coded system is found to be dependent upon the symbol labeling and the number of iterations carried out at the receiver.