Joint turbo equalization and BICM-ID-based IDMA over frequency selective fading channels

This paper proposes a joint turbo equalization and bit interleaved coded modulation with iterative detection-based interleave division multiple access (IDMA) technique over frequency selective fading channels. The transmission chain's parameters are optimized by using extrinsic information transfer-constrained Binary Switching Algorithm at a very low signal-to-noise power ratio range. A frequency domain turbo equalization is used together with IDMA signal detection to deal with all the simultaneous users. Simulation results show that the proposed technique can eliminate both intersymbol interference and multiple access interference, and achieve the excellent frame error rate performance in the cases of single user and 8 users, as well as of 10 users although the user number is larger than its equivalent spreading factor. Furthermore, we also propose a detection ordering technique to improve the efficiency of the detection scheme.