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

• Main Authors: Xi Wu, Yafeng Wang
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Sensors
• Subjects: sparse code multiple access; polar code; partially information coupling; parity check; successive cancellation list; extrinsic information transfer
• Online Access: https://www.mdpi.com/1424-8220/20/23/6740

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 <inline-formula><math display="inline"><semantics><mrow><msub><mi>E</mi><mi>b</mi></msub><mo>/</mo><msub><mi>N</mi><mn>0</mn></msub></mrow></semantics></math></inline-formula>