Analysis and Design of Generalized BICM-T System

The performance of bit-interleaved coded modulation (BICM) using convolutional codes in nonfading channels can be significantly improved if the coded bits are not interleaved at all. This particular BICM system is referred to as BICM trivial (BICM-T). In this paper, we analyze a generalized BICM-T system that uses a nonequally spaced signal constellation in conjunction with a bit-level multiplexer in an additive white Gaussian noise (AWGN) channel. As such, one can exploit the full benefit of BICM-T by jointly optimizing different system modules to further improve its performance. We also investigate the performance of the considered BICM-T system in the Gaussian mixture noise (GMN) channel because of its practical importance. The presented numerical results show that an optimized BICM-T system can offer gains up to 1.5 dB over a non-optimized BICM-T system in the AWGN channel for a target bit error rate of
$10^{-6}$
. The presented results for the GMN channel interestingly reveal that if the strength of the impulsive noise component, i.e., the noise component due to some ambient phenomenon in the GMN, is below a certain threshold level, then the BICM-T system performs significantly better as compared to traditional BICM system.