Sub-graph based joint sparse graph for sparse code multiple access systems

Lai, K., Wen, L., Lei, J., Xiao, P., Maaref, A. and Imran, M. A. (2018) Sub-graph based joint sparse graph for sparse code multiple access systems. IEEE Access, 6, pp. 25066-25080. (doi: 10.1109/ACCESS.2018.2828126)

Abstract

Sparse code multiple access (SCMA) is a promising air interface candidate technique for next generation mobile networks, especially for massive machine type communications (mMTC). In this paper, we design a LDPC coded SCMA detector by combining the sparse graphs of LDPC and SCMA into one joint sparse graph (JSG). In our proposed scheme, SCMA sparse graph (SSG) defined by small size indicator matrix is utilized to construct the JSG, which is termed as sub-graph based joint sparse graph of SCMA (SG-JSG-SCMA). In this paper, we first study the binary-LDPC (B-LDPC) coded SGJSG- SCMA system. To combine the SCMA variable node (SVN) and LDPC variable node (LVN) into one joint variable node (JVN), a non-binary LDPC (NB-LDPC) coded SG-JSG-SCMA is also proposed. Furthermore, to reduce the complexity of NBLDPC coded SG-JSG-SCMA, a joint trellis representation (JTR) is introduced to represent the search space of NB-LDPC coded SG-JSG-SCMA. Based on JTR, a low complexity joint trellis based detection and decoding (JTDD) algorithm is proposed to reduce the computational complexity of NB-LDPC coded SGJSG- SCMA system. According to the simulation results, SG-JSGSCMA brings significant performance improvement compare to the conventional receiver using the disjoint approach, and it can also outperform a Turbo-structured receiver with comparable complexity. Moreover, the joint approach also has advantages in terms of processing latency compare to the Turbo approaches.

• Item Type: Articles
• Additional Information: This work is supported in part by Huawei Technologies Co., Ltd, Ottawa, Canada, in part the National Natural Science Foundation of China under Grant 61502518, 61702536 and 61372098, in part by the National Defense Technology Foundation under Grant 3101168, in part by the Hunan Natural Science Foundation under grant 2017JJ2303, in part by Natural Science Research Project of National University of Defense Technology Research of new multiple access techniques based on joint sparse graph.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Imran, Professor Muhammad
• Authors: Lai, K., Wen, L., Lei, J., Xiao, P., Maaref, A., and Imran, M. A.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: IEEE Access
• Publisher: IEEE
• ISSN: 2169-3536
• ISSN (Online): 2169-3536
• Published Online: 20 April 2018
• Copyright Holders: Copyright © 2018 IEEE. Translations and content mining are permitted for academic research only. Personal use is also permitted, but republication/redistribution requires IEEE permission.
• First Published: First published in IEEE Access 2018 6:25066-25080
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher