Low Complexity Iterative Receiver Design for Sparse Code Multiple Access
arXiv:2002.12181
Abstract
Sparse code multiple access (SCMA) is one of the most promising methods among all the non-orthogonal multiple access techniques in the future 5G communication. Compared with some other non-orthogonal multiple access techniques such as low density signature (LDS), SCMA can achieve better performance due to the shaping gain of the SCMA codewords. However, despite of the sparsity of the codewords, the decoding complexity of the current message passing algorithm (MPA) utilized by SCMA is still prohibitively high. In this paper, by exploring the lattice structure of SCMA codewords, we propose a low complexity decoding algorithm based on list sphere decoding (LSD). The LSD avoids the exhaustive search for all possible hypotheses and only considers signal within a hypersphere. As LSD can be viewed a depth-first tree search algorithm, we further propose several methods to prune the redundancy visited nodes in order to reduce the size of the search tree. Simulation results show that the proposed algorithm can reduce the decoding complexity substantially while the performance loss compared with the existing algorithm is negligible.
Cited by in corpus (5)
- Enabling Sphere Decoding for SCMA
- Sparse or Dense: A Comparative Study of Code-Domain NOMA Systems
- Iterative Receivers for Downlink MIMO-SCMA: Message Passing and Distributed Cooperative Detection
- Message-Passing Receiver Design for Joint Channel Estimation and Data Decoding in Uplink Grant-Free SCMA Systems
- Towrad 5G Air Interface Technology: Sparse Code Muliple Access