Iterative Detection and Decoding for Spatially Coupled Multiuser Data Transmission

• Published in: Communications and Networking Vol. 209; pp. 221 - 231
• Main Authors: Wang, Xiaodan, Wang, Sijie, Si, Zhongwei, He, Zhiqiang, Niu, Kai, Dong, Chao
• Format: Book Chapter
• Language: English
• Published: Switzerland Springer International Publishing AG 2017; Springer International Publishing
• Series: Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering
• Subjects: Detection and decoding; Iterative; Message-passing; NOMA; Spatially coupling
• ISBN: 331966624X; 9783319666242
• ISSN: 1867-8211; 1867-822X
• DOI: 10.1007/978-3-319-66625-9_22

Non-orthogonal multiple access (NOMA) is a candidate multiple access scheme for 5G wireless communication. In this paper we consider applying the principle of spatially coupling in a NOMA system, where coupled data streams from different users transmit via the additive white Gaussian noise (AWGN) multiple access channel. A data stream is constructed by replicating each encoded bit for several times and then permuting the replicated bits. We propose an message-passing algorithm (MPA) based iterative multiuser detection combining with channel decoding, which is illustrated and analysed by the factor graph representation and the extrinsic information transfer (EXIT) chart, respectively. Numerical results show that lower node degree of the spatially coupled structure, higher number of iterations of the detector, and an appropriate encoding/decoding scheme jointly contribute to a better performance of the multiuser transmission system.