EXIT-Chart-Matching-Aided Near-Capacity Coded Modulation Design and a BICM-ID Design Example for Both Gaussian and Rayleigh Channels

Abstract

Bit-interleaved coded modulation with iterative decoding (BICM-ID) is investigated, wherein a novel method of designing amplitude phase-shift keying (APSK) constellations is proposed, which is capable of outperforming both traditional quadrature amplitude modulation (QAM) and nonuniformly spaced QAM (NU-QAM). It is shown that the channel capacity can be approached by the proposed <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$M$</tex></formula> -APSK constellation as <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$M$</tex></formula> tends to infinity. Additionally, a new algorithm is introduced for finding the best bit-to-symbol mapping. Furthermore, when signal space diversity is also employed, our extrinsic information transfer (EXIT) chart analysis and Monte Carlo simulations demonstrate that the proposed BICM-ID schemes exhibit a near-Shannon-capacity performance for transmission over both additive white Gaussian noise (AWGN) and Rayleigh fading channels. For a block length of 64 800 bits, the bit-error-rate (BER) curve of the proposed BICM-ID 16/64-APSK scheme is only about 0.8 and 1.0 dB away from the Gaussian-input Shannon limit over AWGN and Rayleigh fading channels, respectively, at the BER of <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{10}^{-5}$</tex> </formula> and for a code rate of 1/2.