Performance Of Bit-interleaved Coded Modulation Research Articles

Analysis and Design of QC-LDPC Coded BICM Ensembles Based on RCA Density Evolution

This paper presents density evolution (DE) techniques based on reciprocal channel approximation (RCA) for general bit-interleaved coded modulation (BICM) systems. The original RCA-based DE (RCA-DE) technique is implemented under the assumption of binary-input additive white Gaussian noise channels (BI-AWGNCs). In BICM systems, however, <inline-formula> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula>-ary modulation schemes are generally used, and they can be regarded as to be a parallel transmission of <inline-formula> <tex-math notation="LaTeX">$\log _{2} M$ </tex-math></inline-formula> bits. Thus, <inline-formula> <tex-math notation="LaTeX">$\log _{2} M$ </tex-math></inline-formula> separate bit-level channels, which are not Gaussian equivalent, need to be considered. In order to extend the conventional RCA-DE technique to BICM systems, we first establish a model of protograph BICM ensembles. Two methods are developed based on the bit error rate (BER) and the BICM capacity in order to find a corresponding BI-AWGNC that models each of the bit-level channels. Using these methods, we implement the protograph RCA-DE technique for BICM systems and show that it achieves an accurate estimation. As a practical application of the proposed RCA-DE method, we design bit interleavers in order to achieve better BICM performance in the 3GPP New Radio (NR) LDPC coding system. Numerical results show that performance gain of up to 0.3 dB is consistently achieved over a wide range of parameter values.

Performance Analysis for BICM Transmission over Gaussian Mixture Noise Fading Channels

Bit-interleaved coded modulation (BICM) has been adopted in many systems and standards for spectrally efficient coded transmission. The analytical evaluation of BICM performance parameters, in particular bit-error rate (BER), has received considerable attention in the recent past. In this paper, we derive BER approximations for BICM transmission over general fading channels impaired by Gaussian mixture noise (GMN). To this end, we build upon the saddlepoint approximation of the pairwise error probability (PEP) and a recently established approximation for the probability density function (PDF) of bit-wise reliability metrics for nonfading additive white Gaussian noise (AWGN) channels. We extend this PDF approximation to the case of GMN, and obtain closed-form expressions for its Laplace transform for fading GMN channels. The latter allows us to express the PEP and thus BER via the saddlepoint approximation. For the special case of fading AWGN channels the presented approximations are closed form, since the saddlepoint is well approximated by 1/2 for BICM decoding. Furthermore, we derive closed-form PEP expressions also for GMN channels in the high signal-to-noise ratio regime and establish the diversity and coding gain for BICM transmission over fading GMN channels. Selected numerical results for the BER of convolutional coded BICM highlight the usefulness of the proposed approximations and the differences between AWGN and GMN channels.

The Performance of BICM With a Single Decision Feedback for the AWGN Channel

This paper studies the performance of bit interleaved coded modulation (BICM) with a single decision feedback. The separation of demodulation and decoding in BICM inevitably reduces the channel's capacity. Altering the conventional bit mapping in BICM and allowing a single decision feedback greatly reduces the capacity loss. The extra complexity introduced by the single decision feedback appears well justified for dense constellations.

BER Evaluation of BICM-ID via Bonferroni-Type Bounds

In this paper, we evaluate the bit error rate (BER) of bit-interleaved coded modulation (BICM) receivers that operate with a priori information obtained from the decoder during the so-called turbo iterations. We use Bonferroni-type lower and upper bounds to tightly estimate the BER performance in the range of signal-to-noise ratio (SNR) of interest. The results are shown to be useful for the convergence analysis of the iterative demapping via the so-called extrinsic information transfer (EXIT) charts and for the evaluation of the coded performance of BICM with iterative demapping (BICM-ID).

On the performance of BICM with mapping diversity in hybrid ARQ

AbstractHybrid ARQ with packet combining for high‐order modulations (such as 16‐QAM) may be significantly enhanced if the bits‐to‐symbols mappings are appropriately changed throughout the transmissions. In this paper, we analyze the relationship between such mapping diversity and channel coding. We calculate the capacity of the popular bit‐interleaved‐coded modulation (BICM) to draw qualitative and approximate quantitative conclusions that are valid for strong codes approaching the capacity limits. We conclude that the choice/design of the appropriate mapping depends on the targeted spectral efficiency and we demonstrate that certain forms of mapping diversity may be counterproductive. We also show that iterative demapping may be successfully applied to significantly reduce (by more than 1 dB) the gap between the BICM and coded modulations (CM) capacities. The analysis is illustrated with results obtained when the mapping diversity is combined with practical turbo codes. Copyright © 2007 John Wiley &amp; Sons, Ltd.

A Tight BER Upper Bound for Bit-Interleaved Coded Modulation with Square QAM and Gray Labeling

Bit-interleaved coded modulation (BICM) is a bandwidth-efficient coded system with diversity order higher than that of Ungerboeck's trellis-coded modulation on fading channels. In this paper, we investigate the BER (bit error rate) performance of BICM in the additive white Gaussian and Rayleigh fading channels. A new upper bound is given for the square QAM constellation with gray labeling, which constitutes a large portion of practical applications of BICM systems. The new upper bound is tighter than the well-known BICM union bound proposed in G. Caire et al. (1998)