Mapping optimization for space-time block coded OFDM systems with iterative decoding

An iterative detection scheme enhances the performance of bit-interleaved coded modulation (BICM) by exploiting frequency diversity gains. Additionally, space-time block coding (STBC) scheme can significantly improve the system performance in fading channels by proper coordinating of the signaling over multiple antennas. In this paper, STBC technique based on BICM is applied to orthogonal frequency division multiplexing (OFDM) system over frequency selective channels. When iterative decoding (ID) is applied, the overall performance of the STBC BICM-ID OFDM is affected by the chosen mapping. We classify the mapping selection and search for the optimal mapping for the proposed system. Simulation results show that up to 3 dB gain is achieved for 8PSK and 16QAM in various conditions.