Bit-interleaved Coded Modulation With Iterative Decoding Research Articles

Labeling-Based Recipient Identification with Low-Order Modulation

Labeling-Based Recipient Identification (LABRID) brings the possibility of representing the destination station address in a Bit-Interleaved Coded Modulation with Iterative Decoding (BICM-ID) system by a signal labeling rule. Low-order modulations, such as BPSK or QPSK, pose a general problem for BICM-ID due to a limited convergence of iterative decoding. In the context of LABRID, they have one more drawback—a small number of different labeling rules in general; the number of the optimal ones, which exhibit the maximal asymptotic coding gain, is reduced even further. Meanwhile, LABRID needs a sizable collection of different optimal labeling rules to serve many users in large wireless networks. In this paper, the author suggests the use of hypercube BPSK or QPSK labeling to overcome all these challenges. By means of the Reactive Tabu Search (RTS) algorithm, more than 1500 equivalent optimal hypercube labeling rules are found. Analytical error bounds of the system are developed and supported by simulation experiments. Then, the focus is moved to the criterion to determine the frame destination at the LABRID receiver; a simple threshold-based method is proposed to keep the incorrect decision probability below 10−5. Finally, it is shown that LABRID outperforms a reference BICM-ID system in terms of computational complexity.

BICM-ID Labeling-Based Recipient Identification in a Heterogeneous Network

The concept of labeling-based recipient identification (LABRID) for bit-interleaved coded modulation with iterative decoding (BICM-ID) is revisited. LABRID allows addressing a message recipient station in a wireless network by using an individual labeling map without compromising error performance. This eliminates the need to use any byte of the data frame to carry the recipient address explicitly. In addition, the destination of the frame can be determined in parallel with a BICM-ID decoding procedure in the receiver's physical layer. Therefore, the MAC layer is not involved in processing the vast majority of frames transmitted in a network. Previously, it was shown that LABRID works fine if there are only LABRID-compatible stations within the network, and every receiver can reject frames destined for other receivers. This paper considers a scenario in which LABRID-compatible BICM-ID stations and legacy BICM stations coexist in the same network. A few experiments show that the LABRID receiver can reject an old-fashioned BICM frame by judging the convergence of the iterative decoding process. It also turns out that the legacy BICM receiver can identify and dismiss the LABRID-type frames thanks to the standard cyclic redundancy check (CRC) procedure.

Bit-Interleaved Coded Energy-Based Modulation With Iterative Decoding

This paper develops a low-complexity suboptimal non-coherent receiver for a multi-level energy-based coded modulation system. Inspired by the turbo processing principle, we incorporate the fundamentals of bit-interleaved coded modulation with iterative decoding (BICM-ID) into the proposed receiver design. The resulting system is called bit-interleaved coded energy-based modulation with iterative decoding (BICEM-ID) and its error performance is analytically studied. Specifically, we derive upper bounds on the average pairwise error probability (PEP) of the non-coherent BICEM-ID system in the feedback-free (FF) and error-free feedback (EFF) scenarios. It is revealed that the definition of the nearest neighbors, which is important in the performance analysis in the FF scenario, is very different from that in the coherent BICM-ID counterpart. The analysis also reveals how the mapping from coded bits to energy levels influences the diversity order and coding gain of the BICEM-ID systems. A design criterion for good mappings is then formulated, and an algorithm is proposed to find a set of best mappings for BICEM-ID. Finally, simulation results corroborate the main analytical findings.

A Probabilistic Shaping Scheme for Bit-Interleaved Coded Modulation With Iterative Decoding

In this letter, a probabilistic shaping (PS) scheme for bit-interleaved coded modulation with iterative decoding (BICM-ID) between low density parity check (LDPC) decoder and demodulator is proposed. Compared to conventional LDPC-coded 8-quadrature amplitude modulation (QAM) system on additive white Gaussian noise (AWGN) channel, when spectral efficiency (SE) is 2.10 bits/s/Hz, the proposed PS-8QAM scheme for BICM-ID can obtain 0.73 dB theoretical gain, where the simulated error performance gain is 1.02 dB with frame error rate (FER) at 10−3. Compared to conventional LDPC-coded 32QAM system on AWGN channel, when SE is 3.75 bits/s/Hz, the proposed PS-32QAM scheme for BICM-ID can obtain 1.08 dB theoretical gain, where the simulated error performance gain is 1.10 dB with FER at 10−3. Both the information-theoretic analysis and simulated error performance show that the proposed PS scheme for BICM-ID is reliable, which is suitable for non gray mapped constellations.

Adaptive protograph-based BICM-ID relying on the RJ-MCMC algorithm: a reliable and efficient transmission solution for plasma sheath channels

For reentry communication, owing to the influence of the highly dynamic plasma sheath (PS), the parasitic modulation effect can occur and the received phase shift keying (PSK) signal constellation can be severely rotated, leading to unacceptable demodulation performance degradation. In this work, an adaptive non-coherent bit-interleaved coded modulation with iterative decoding (BICM-ID) system with binary PSK (BPSK) modulation and protograph low-density parity-check under the PS channel is proposed. The proposed protograph-based BICM-ID (P-BICM-ID) system can achieve joint processing of demodulation and decoding, where the soft information is adaptively estimated by reversible-jump Markov chain Monte Carlo (RJ-MCMC) algorithms. Simulation results indicate that compared to existing algorithms, the proposed system can adapt well to the dynamic characteristics of the PS channel and can obtain a 5 dB performance improvement at a bit error rate of 10−6.

Multi-User Interference Cancellation for Uplink FBMC-Based Multiple Access Channel

In the uplink of multi-user systems, signals from different users may arrive at the base station with different timing offsets (TO), which degrades the performance of conventional OFDM systems. In this letter, an FBMC-based multiple access channel with timing errors is considered under frequency selective channels. To eliminate the intrinsic interference (InI), TO-induced interference (TOI) and multi-user interference (MUI) terms, an iterative receiver is proposed. The proposed receiver combines bit-interleaved coded modulation with iterative decoding (BICM-ID) processing with parallel interference cancellation and iterative interference cancellation. The results show that FBMC is robust to timing errors and the proposed receiver can effectively eliminate the interference terms. This motivates the use of FBMC as an alternative to OFDM in applications that require asynchronous transmissions.

Protograph LDPC-Coded BICM-ID With Irregular Mapping: An Emerging Transmission Technique for Massive Internet of Things

Bit-interleaved coded modulation with iterative decoding (BICM-ID) is a key technology enabling the communication systems to realize reliable and efficient data transmission. In this work, we present a study on the adaptive irregular-mapping (AIM)-aided BICM-ID systems with the use of protograph low-density parity-check (PLDPC) codes. To be specific, we first propose a three-step design strategy to generate a type of adaptive constellations, which can be combined with their corresponding initial constellations to formulate an AIM scheme for improving the BICM-ID performance. Then, we put forward a theoretical-analysis tool, called AIM-based protograph extrinsic information transfer (PEXIT) algorithm, to estimate the convergence performance of PLDPC codes in the AIM-aided BICM-ID systems. By making use of such an algorithm, we further develop a code-design method to construct a new type of PLDPC codes, called enhanced PLDPC codes, tailored for the AIM-aided BICM-ID systems. Both convergence analysis and simulations indicate that the proposed AIM-aided BICM-ID systems perform better than the existing counterparts, and their performance can be significantly improved by using the enhanced PLDPC codes. Consequently, the proposed designs have great potential to meet the high-reliability, high-throughput, and strong link-adaptation requirements of future wireless-communication scenarios, such as green Internet of Things (IoT).

Design and Convergence Analysis of an IIC-based BICM-ID Receiver for FBMC-QAM Systems

Next generation cellular networks are expected to connect billions of devices through its massive machine-type communication (mMTC) use case. To achieve this, waveforms with improved spectral confinement and high spectral efficiency compared to cyclic-prefix orthogonal division multiplexing (CP-OFDM) are required. In this paper, filter-bank muilticarrier with quadrature amplitude modulation (FBMC-QAM) is studied as an alternative to CP-OFDM for such applications. However, FBMC-QAM presents the challenge of high intrinsic interference due to the loss of complex orthogonality in time-frequency domain. Bit-interleaved coded modulation with iterative decoding (BICM-ID) has been shown to exhibit capacity-approaching decoding performance. Therefore, in this paper, an iterative interference cancellation (IIC) based BICM-ID receiver is designed to cancel the intrinsic interference in FBMC-QAM systems. The proposed receiver consist of an inner decoder, which combines iterative demodulation and interference cancellation, and an outer decoder which is a low density parity check (LDPC) channel decoder. To evaluate the convergence behaviour of the proposed receiver, extrinsic information transfer (EXIT) chart analysis is employed, where EXIT curves for the components of the iterative decoder are derived. Numerical results show that the intrinsic interference in FBMC-QAM systems can be removed by adopting the proposed IIC-based BICM-ID receiver. With a receiver that is able to successfully cancel intrinsic interference, FBMC-QAM becomes an interesting alternative waveform for asynchronous mMTC applications due to its superior frequency localization compared to CP-OFDM. Furthermore, it has been shown that FBMC-QAM with the IIC-based receiver can achieve similar bit-error-rate (BER) performance as a CP-OFDM benchmark under different fading channels. Finally, the complexity of the proposed receiver for FBMC-QAM is analysed and compared to the complexity of the CP-OFDM benchmark.

Analysis and Optimization of Tail-Biting Spatially Coupled Protograph LDPC Codes for BICM-ID Systems

As a typical example of bandwidth-efficient techniques, bit-interleaved coded modulation with iterative decoding (BICM-ID) provides desirable spectral efficiencies in various wireless communication scenarios. In this paper, we carry out a comprehensive investigation on tail-biting (TB) spatially coupled protograph (SCP) low-density parity-check (LDPC) codes in BICM-ID systems. Specifically, we first develop a two-step design method to formulate a novel type of constellation mappers, referred to as labeling-bit-partial-match (LBPM) constellation mappers, for SC-P-based BICM-ID systems. The LBPM constellation mappers can be seamlessly combined with high-order modulations, such as M-ary phase-shift keying (PSK) and M-ary quadrature amplitude modulation (QAM). Furthermore, we conceive a new bit-level interleaving scheme, referred to as variable node matched mapping (VNMM) scheme, which can substantially exploit the structure feature of SC-P codes and the unequal protection-degree property of labeling bits to trigger the wave-like convergence for TB-SC-P codes. In addition, we propose a hierarchical extrinsic information transfer (EXIT) algorithm to predict the convergence performance (i.e., decoding thresholds) of the proposed SC-P-based BICM-ID systems. Theoretical analyses and simulation results illustrate that the LBPM-mapped SC-P-based BICM-ID systems are remarkably superior to the state-of-the-art mapped counterparts. Moreover, the proposed SC-P-based BICM-ID systems can achieve even better error performance with the aid of the VNMM scheme. As a consequence, the proposed LBPM constellation mappers and VNMM scheme make the SC-P-based BICM-ID systems a favorable choice for the future-generation wireless communication systems.

Labeling-Based Recipient Identification for 16-QAM BICM-ID

In recent years, many efforts have been made to find the optimal labeling maps for bit-interleaved coded modulation with iterative decoding (BICM-ID) with the aim to exploit the benefits of iterative decoding to the maximal extent. The current paper reveals new opportunities that BICM-ID signal labeling brings for system designers: it enables recipient addressing without any explicitly sent identifier. Instead, the recipient ID is represented by a labeling map, selected from a set of equally optimal labelings. A simple method of frame filtering, necessary to retrieve the desired data frame at the receiver side, is proposed and evaluated. It is also shown that the proposed Labeling-Based Recipient Identification (LABRID) approach does not cause any inferior performance outcome in terms of bit error rate.

Iterative demodulation and decoding of polar coded BICM with bit-flipping

A new bit-interleaved coded modulation with iterative decoding (BICM-ID) scheme for polar codes is proposed, in which a flipping-based successive cancellation list (SCL) decoder is employed. This enhanced decoder can provide a large number of hard-decision outputs, from which only a few paths are selected and re-encoded to obtain a candidate set. Combined with the received signals and Pyndiah’s approximation, the candidate set generates extrinsic information which will be transmitted to the demodulator as the priori information after being interleaved. With the iterative decoding, the error performance of polar coded BICM scheme can be significantly improved. Simulation results show that the proposed flipping-based SCL decoder not only performs much better than the conventional SCL decoder with the same list size, but also shows competitiveness with some existing improved approaches of SCL decoding. More importantly, it generates efficient soft information which greatly improve the performance after iterative demodulation and decoding. Furthermore, the average complexity of the proposed BICM-ID scheme is acceptable and is similar to an SCL decoder at medium to high signal to noise ratio (SNR).

Novel Method for Multi-Dimensional Mapping of Higher Order Modulations for BICM-ID Over Rayleigh Fading Channels

Multi-dimensional (MD) mapping offers more flexibility in mapping design for bit-interleaved coded modulation with iterative decoding (BICM-ID) and potentially improves the bandwidth efficiency. However, for higher order signal constellations, finding suitable MD mappings is a very complicated task due to the large number of possible mappings. In this paper, a novel mapping method is introduced to construct efficient MD mappings to improve the error performance of BICM-ID over Rayleigh fading channels. We propose to break the MD mapping design problem into four distinct 2-D mapping functions. The 2-D mappings are designed such that the resulting MD mapping improves the BICM-ID error performance at low signal-to-noise ratios (SNRs). We also develop cost functions that can be optimized to improve the error performance at high SNRs. The proposed mapping method is very simple compared to well-known mapping methods, and it can achieve suitable MD mappings for different modulations including higher order modulations for BICM-ID. The simulation results show that our mappings significantly outperform the previously known mappings at a target bit error rate (BER) of 10−6. Our mappings also offer a lower error-floor compared to their well-known counterparts.

Bit Labeling and Code Searches for BICM-ID Using 16-DAPSK

Bit-interleaved coded modulation with iterative decoding (BICM-ID) is suitable for correlated Rayleigh fading channels. Additionally, BICM-ID using differential encoding can avoid the pilot overhead. In this paper, we consider BICM-ID using 16-DAPSK (differential amplitude and phase-shift keying). We first derive the probability of receiving signals conditioned on the transmission of input bits for general differential encoding; then we propose two new 16-DAPSK bit labeling methods. In addition, convolutional codes for the new bit labeling are developed. Both the minimum distance and the simulation results show that the proposed labeling has better error performance than that of the original differential encoding, and the searched new codes can further improve the error performance.

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

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

BICM-ID with Physical Layer Network Coding in TWR Free Space Optical Communication Links

Physical layer network coding (PNC) is a promising technique to improve the network throughput in a two-way relay (TWR) channel for two users to exchange messages across a wireless network. The PNC technique incorporating a TWR channel is embraced by a free space optical (FSO) communication link for full utilization of network resources, namely TWR-FSO PNC. In this paper, bit interleaved coded modulation with iterative decoding (BICM-ID) is adopted to combat the deleterious effect of the turbulence channel by saving the message being transmitted to increase the reliability of the system. Moreover, based on this technique, comparative studies between end-to-end BICM-ID code, non-iterative convolutional coded and uncoded systems are carried out. Furthermore, this paper presents the extrinsic information transfer (ExIT) charts to evaluate the performance of BICM-ID code combined with the TWR-FSO PNC system. The simulation results show that the proposed scheme can achieve a significant bit error rate (BER) performance improvement through the introduction of an iterative process between a soft demapper and decoder. Similarly, Monte Carlo simulation results are provided to support the findings. Subsequently, the ExIT functions of the two receiver components are thoroughly analysed for a variety of parameters under the influence of a turbulence-induced channel fading, demonstrating the convergence behaviour of BICM-ID to enable the TWR-FSO PNC system, effectively mitigating the impact of the fading turbulence channel.

Iterative Channel Coded Physical Layer Network Coding on Impulsive Noise Channels

Physical-Layer Network Coding (PNC) employed on a conventional two-way relay communications is an active research area due to the potential doubling of the throughput compared with traditional routing. In this paper, we investigate the effects of impulsive noise added at the relay and sink nodes of a TWRC employing link-by-link coded PNC. The Gaussian mixture model is chosen to model the impulsive noise and the performance of bit-interleaved coded modulation with iterative decoding (BICM-ID) and turbo codes on the conventional two-way relay communications is evaluated through simulation results for different mixtures, , of impulsive noise. For high and low values of the turbo codes outperform trellis BICM, but it is shown that for values between = 0.1 and = 0.5, a PNC system with trellis BICM outperforms a comparable PNC system with turbo codes, where both coding schemes have the same block size, code rate and constraint length.

On the Sum Rate of BICM-ID Transmission Over Vector-Perturbation Precoding in Multiuser Downlink

This paper proposes a channel code for vector perturbation (VP) precoded transmission in multiuser downlink and examines its achievable sum-rate performance. In particular, we first find the most suitable outer convolutional code (CC) for VP precoded transmission under bit-interleaved coded modulation with iterative decoding (BICM-ID) by applying a semi-analytic technique based on extrinsic information transfer charts. We then study the achievable sum rate of the proposed BICM-ID-based VP precoded system, and we compare it with the sum capacity of the dirty paper coding (DPC) scheme. Our investigation shows that under perfect channel state information (CSI), the sum rate of the proposed system grows linearly over the number of users, which is the same growth of the DPC. Under quantized CSI and finite-rate feedback, a linear increase in feedback overhead per user is necessary to maintain such a linear sum-rate growth.

IRREGULAR REPETITION CODE HYBRID ARQ IN WIRELESS SYSTEM

Error control consists of error detection and error correction in the communication system. The purpose of this research work is to reduce error in the wireless communication system by using the advantages of both error correction techniques which are forward error correction (FEC) and automatic repeat request (ARQ). Thus, error can be corrected without retransmission and also via retransmission(s) when needed. Combination of FEC and ARQ is known as Hybrid ARQ. In this paper, Hybrid ARQ system is designed using three components which are the irregular repetition code (IRC) as a simple code, bit-interleaved coded modulation with iterative decoding (BICM-ID) as a simple Turbo processing and ARQ. The HARQ system is enhanced by the extended mapping (EM) adopted in the mapping system. The performance of the systems is evaluated in the additive white Gaussian noise (AWGN). The results show the Hybrid ARQ with extended mapping (Hybrid ARQ-EM) outperforms Hybrid ARQ with standard mapping (Hybrid ARQ-SM). Hybrid ARQ-EM achieves low bit error rate BER (10-5) at low signal-to-noise ratio SNR which only 3.03dB close to the theoretical limit. The proposed system Hybrid ARQ-EM achieves 52 percent gain enhancement of SNR gap from the theoretical limit compared to Hybrid ARQ-SM. Hybrid ARQ-EM gives better performance although in worse channel condition.

Distributed Linear Constellation Precoding with BICM/BICM-ID in Two-Way Relaying Communications

This paper investigates distributed linear constellation precoding (DLCP) for two-way relaying communication systems in conjunction with the techniques of bit-interleaved coded modulation (BICM) and BICM with iterative decoding (BICM-ID). First, a decoding strategy for the relay node that is based on quaternary code representation is developed. Then, the union bounds (for the case of BICM) and error-free feedback bounds (for the case of BICM-ID) on the quaternary digit error probability and bit error probability under network coding in the multiple-access (MA) phase are obtained. Based on the obtained bounds, the impact of DLCP on the error performance is analyzed by considering three error types in the MA phase. It is shown that type-3 errors need to be carefully taken into account in the design of a DLCP scheme. By developing a performance metric related to type-3 errors, the design parameter of DLCP is optimized when BICM is used, whereas it is shown that DLCP is not needed when BICM-ID is used. Extensive simulation results are provided to corroborate the analysis and demonstrate the performance superiority of the proposed decoding strategy over the one that directly decodes the exclusive-OR ( xor ) code. For the case of BICM, the performance advantage achieved by properly designing DLCP is also illustrated.

Analysis of BICM-ID Receivers Exploiting Transformations of Extrinsic Information

In this article we analyze a novel idea to increase the applicability of Bit Interleaved Coded Modulation with Iterative Decoding (BICM-ID) to legacy waveforms. One essential design parameter of BICM-ID receivers with respect to the error correcting capabilities is the symbol mapping of the digital modulation scheme. A so-called Semi-Set Partitioning (SSP) symbol mapping is well known to provide higher stepwise gains in robustness in every iteration than a Gray encoded symbol mapping. The novel approach is based on the idea to make in a first step of BICM-ID the deliberately false assumption that a well performing symbol mapping has been used at the transmitter, even though in reality a less powerful symbol mapping was applied. In a second step, the mismatch in both symbol mappings is compensated by an innovative Transformation of Extrinsic Information (TEI). After having reviewed the innovative TEI idea in more detail, we will discuss the fundamentals of the required signal processing. In addition, as a novelty of this article we will analyze three different ways to implement the TEI approach. Several simulation results will be shown which demonstrate the theoretically achievable performance gains.