Efficient Multi-Dimensional Mapping Using QAM Constellations for BICM-ID

Abstract

Bit-interleaved coded modulation with iterative decoding (BICM-ID) offers very good error performance over additive white Gaussian noise (AWGN) and fading channels if it uses a wisely designed signal mapping. Further, error performance of BICM-ID can significantly be improved by employing multi-dimensional (MD) modulation. However, suitable MD mappings are obtained by computer search techniques except for MD modulations that use smaller constellation e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK) and $8$-ary phase shift keying ($8$-PSK) as basic modulation. The alphabet size of MD modulations increases exponentially as the order of the basic modulation increases and computer search becomes intractable. In this paper, we propose a systematic mapping method for MD modulations. The innovativeness of our proposed method is that it generates MD mappings using $16$- and $64$-quadrature amplitude modulation (QAM) very efficiently. The presented numerical results show that the proposed method improves bit error rate (BER) of BICM-ID.