scholarly journals Improving Polar-Coded SCMA System by Information Coupling and Parity Check

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6740
Author(s):  
Xi Wu ◽  
Yafeng Wang
Keyword(s):  
Information Transfer ◽  
Multiple Access ◽  
Iterative Detection ◽  
Bayes Rule ◽  
Parity Check ◽  
Extrinsic Information ◽  
Polar Code ◽  
Successive Cancellation ◽  
Simulation Results ◽  
Encoding Method

In this paper, the uplink information-coupled polar-coded sparse code multiple access (PC-SCMA) system is proposed. For this system, we first design the encoding method of systematic joint parity check and CRC-aided (PCCA) polar code. Using the systematic PCCA-polar code as base code, the partially information-coupled (PIC) polar code is constructed. Then, a joint iterative detection and successive cancellation list (SCL)-decoding receiver is proposed for the PC-SCMA system. For the receiver, the coupled polar decoder’s extrinsic messages are calculated by the Bayes rule and soft cancellation (SCAN) algorithm. Based on the extrinsic information transfer (EXIT) idea, the PIC PCCA-polar code is optimized. Simulation results demonstrate that the PIC PCCA-PC-SCMA system outperforms the other polar (or LDPC) coded SCMA systems at various code rates and channel configurations. Additionally, compared with an uncoupled PC-SCMA system with SCL decoder, the complexity of PIC PCCA-PC-SCMA is reduced at a high Eb/N0

scholarly journals Adding a Rate-1 Third Dimension to Parallel Concatenated Systematic Polar Code: 3D Polar Code

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Zhenzhen Liu ◽  
Kai Niu ◽  
Chao Dong ◽  
Jiaru Lin
Keyword(s):  
Full Advantage ◽  
Information Transfer ◽  
Three Dimensional ◽  
Error Floor ◽  
Extrinsic Information ◽  
Exit Chart ◽  
Convergence Behavior ◽  
Polar Code ◽  
Simulation Results ◽  
Third Dimension

In this paper, a three-dimensional polar code (3D-PC) scheme is proposed to improve the error floor performance of parallel concatenated systematic polar code (PCSPC). The proposed 3D-PC is constructed by serially concatenating the PCSPC with a rate-1 third dimension, where only a fraction λ of parity bits of PCSPC are extracted to participate in the subsequent encoding. It takes full advantage of the characteristics of parallel concatenation and serial concatenation. In addition, the convergence behavior of 3D-PC is analyzed by the extrinsic information transfer (EXIT) chart. The convergence loss between PCSPC λ=0 and different λ provides the reference for choosing the value of λ for 3D-PC. Finally, the simulation results confirm that the proposed 3D-PC scheme lowers the error floor.

Optimization of LDPC Codes by Extrinsic Information Transfer Chart

2013 ◽  
Vol 427-429 ◽  
pp. 1518-1523
Author(s):  
Jing Xi Zhang
Keyword(s):  
Information Transfer ◽  
Multiple Access ◽  
Gaussian Approximation ◽  
Additive White Gaussian Noise ◽  
Ldpc Code ◽  
Multiple Access Channel ◽  
Parity Check ◽  
Extrinsic Information ◽  
Access Channel ◽  
Check Matrix

The optimization of degree profiles of low-density parity-check (LDPC) code in additive white Gaussian noise (AWGN) multiple access channel (MAC) by fitting the transfer characteristics of variable nodes detector (VND) and that of check nodes detector (CND) is discussed. Extrinsic information transfer (EXIT) characteristics are used for determining the degree profiles based on curve fitting. The convergence the optimized LDPC code is ensured by the EXIT characteristics of VND and CND. Degree profiles are obtained and check matrix is constructed. Simulation results show that the method is variable in designing LDPC code degree profiles in MAC with reduced complexity compared with density evolution based on Gaussian approximation.

scholarly journals Convergence analysis of the unpunctured turbo trellis-coded modulation (UTTCM)

2019 ◽  
Vol 13 (2) ◽  
pp. 447
Author(s):  
Ahmed Haffane ◽  
Abdelhafid Hasni ◽  
Mustapha Khelifi ◽  
Boufeldja Kadri
Keyword(s):  
Gaussian Noise ◽  
Iterative Decoding ◽  
Information Transfer ◽  
Additive White Gaussian Noise ◽  
Coded Modulation ◽  
Extrinsic Information ◽  
Trellis Coded Modulation ◽  
Exit Chart ◽  
Trellis Coded ◽  
Simulation Results

In this paper, the performance of the Unpunctured Turbo Trellis-Coded Modulation (UTTCM) over Additive White Gaussian Noise (AWGN) channel is analyzed using the non-binary extrinsic information transfer (EXIT) chart. The exchange of the extrinsic information between the decoder components is tracked, allowing the generation of an EXIT chart, which is a powerful tool for analyzing the convergence behavior of iterative decoding and prediction of convergence position. The Simulation results are compared with the turbo cliff positions on the BER curves.

Image Transmission Based on QC-LDPC Codes with Simple Recursive Encoding Form

2014 ◽  
Vol 602-605 ◽  
pp. 3223-3227
Author(s):  
Hua Xu
Keyword(s):  
Information Transfer ◽  
Ldpc Codes ◽  
Ldpc Code ◽  
Image Transmission ◽  
Parity Check ◽  
Extrinsic Information ◽  
Transmission Scheme ◽  
Check Matrix ◽  
Exponent Matrix ◽  
Base Matrix

Low encoding delay and complexity is very important for image transmission. This paper proposes a novel image transmission scheme with low encoding complexity. The proposed scheme is based on quasi-cyclic low density parity check (QC-LDPC) codes with a simple recursive encoding form (SREF QC-LDPC code) which results in low encoding complexity and delay. Constructing the SREF QC-LDPC codes in this scheme composes of two main steps, construction of the base matrix and the exponent matrix. We combine the differential evolution and protograph extrinsic information transfer (PEXIT) method to optimize the base matrix of QC-LDPC code. Consequently, the exponent matrix and the parity check matrix are constructed. Simulation results show that the proposed scheme based on SREF QC-LDPC code can provide a good tradeoff between the performance and complexity.

scholarly journals Conceiving Extrinsic Information Transfer Charts for Stochastic Low-Density Parity-Check Decoders

IEEE Access ◽  
2018 ◽  
Vol 6 ◽  
pp. 55741-55753
Author(s):  
Asun Perez-Pascual ◽  
Alex Hamilton ◽  
Robert G. Maunder ◽  
Lajos Hanzo
Keyword(s):  
Information Transfer ◽  
Low Density ◽  
Parity Check ◽  
Extrinsic Information ◽  
Low Density Parity Check

scholarly journals On efficient designing of protograph LDPC codes

2021 ◽  
Vol 19 (6.2) ◽  
pp. 39
Author(s):  
Huong-Giang Nguyen ◽  
Nghia Xuan Pham ◽  
Thu Phuong Nguyen ◽  
Chi Dinh Nguyen
Keyword(s):  
Information Transfer ◽  
Ldpc Codes ◽  
Code Rate ◽  
Weight Enumerator ◽  
Error Floor ◽  
Extrinsic Information ◽  
Simple Method ◽  
Prior Art ◽  
Simulation Results

This paper designs two protograph LDPC codes with code-rate $R > 1/2$. A simple method using the protograph extrinsic information transfer (PEXIT) to design the codes with a low decoding threshold and the asymptotic weight enumerator (AWE) to evaluate the error floor of the codes is deployed. Simulation results show that the proposed codes have a better error floor than prior art protograph codes and offer higher rate protographs.

scholarly journals Sparse Signature Matrix Optimization for NOMA under Imperfect CSI

2021 ◽  
Author(s):  
Kun Lu ◽  
Hongwen Yang
Keyword(s):  
Iterative Decoding ◽  
Information Transfer ◽  
Multiple Access ◽  
Rapid Development ◽  
Minimum Mean Square Error ◽  
Accurate Information ◽  
Analysis Tool ◽  
Matrix Optimization ◽  
High Spectral Efficiency ◽  
Signature Matrix

Abstract Non-orthogonal multiple access (NOMA) can support the rapid development of the Internet of Things (IoT) with its potential to support high spectral efficiency and massive connectivity. The low-density superposition modulation (LDSM) scheme is one of the NOMA schemes and uses the sparse signature matrix to reduce multiple access interferences (MAI). In order to improve the NOMA system performance in practice, this paper focuses on designing the sparse signature matrix with a large girth for LDSM under imperfect channel state information (CSI). Based on the orthogonal pilot and linear minimum mean square error (LMMSE) estimation, the LDSM optimized by bare-bone particle swarm optimization (BBPSO) algorithm has a larger girth and can gather more accurate information in the process of iterative decoding convergence. An extrinsic information transfer (EXIT) chart analysis is designed for the LDSM-OFDM system as a theoretical analysis tool. The simulation results show that the optimized LDSM outperforms the reference LDSM system, bringing about a 0.5 dB performance gain.

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