Design, analysis, and performance evaluation for BICM-ID with square QAM constellations in Rayleigh fading channels

Abstract

We consider bit-interleaved coded modulation with iterative decoding (BICM-ID) for bandwidth-efficient transmission over Rayleigh fading channels. We propose the design criteria that utilize a large Hamming distance inherited in a low-rate code and a new labeling technique designed specifically for fading channels. This results in large coding gain over noniterative coded modulation and performance close to that of "turbo" coded modulation with less complexity. We also show that BICM-ID designed for fading channel usually has a very good performance over the additive white Gaussian noise (AWGN) channel while the converse is difficult to achieve. When combined with signal space diversity, diversity order can be improved to twice the diversity order of conventional BICM-ID; therefore, the code complexity can further be reduced while maintaining the same level of performance. Specifically, with the bandwidth efficiency of 2 bits/s/Hz over Rayleigh fading channels, a bit error rate (BER) of 10 6 can be achieved with 16-QAM, a four-state rate 1/2 code at 0 of about seven dB. We also derive performance bounds for BICM-ID with and without signal space diversity over Rayleigh fading channels, which can be easily extended for other types of fading channels.

EXIT Chart Analysis of Iterative Demodulation and Decoding of MPSK Constellations with Signal Space Diversity

“…This allows a coded modulation system with moderate complexity to have large diversity order and achieve coding gain in fading environments [2]. Furthermore, in [3], [4] it was shown that iterative decoding (ID) can increase the minimum intersignal Euclidean distance of bit interleaved coded modulation (BICM), while retaining the desirable Hamming distance. SSD can provide performance improvement over fading channels by maximizing the diversity of a communication system [1].…”

Iterative Detection Techniques for Clipped OFDM Systems

“…We adopt a simple strategy by treating D in (6) as an independent Gaussian noise. With this strategy, the demapping method used for BICM [9] can be applied here to evaluate (7). At the start, without any information about clpn(x), we simply set c = 0 in (6).…”

“…(iii) Generate the soft estimate of the clipping noise using (9). Steps (i)-(iii) are performed respectively by the soft mapper, IDFT and SC modules in the ESE.…”

“…Hence, the channel noise may dominate the performance and forward error control coding (FEC) can ensure good results. In highrate cases with coded modulation (such as the bit-interleaved coded modulation (BICM) [9]), the system works at a higher SNR. Thus, the non-linear distortion has a more significant impact and FEC alone may not be sufficient.…”

Algorithm for Generating All Optimal 16-QAM BI-STCM-ID Labelings

“…Since bit-interleaved coded modulation with iterative decoding (BICM-ID) was introduced [1,2], there have been many efforts made to analyze the impact of applied signal labeling on the system performance. Some researchers tried moving the position of constellation points for a given modulation order, e.g., [3,4], but in most cases the constellation points were fixed and the research focused on solving a combinatorial problem of associating binary labels with constellation points of well known modulations, like 8-PSK, 16-QAM, and 64-QAM [3,[5][6][7].…”