Design of Codebook for Non-Binary Polar Coded SCMA

Abstract

As a new non-orthogonal multiple access (NOMA) access technology, sparse code multiple access (SCMA) can effectively improve the resource utilization of communication system, so it can meet the needs of massive access for IoT service. In this paper, a design method of SCMA codebook is proposed based on the maximum sum of Euclidean distances (MSED) criterion between constellation points. Meanwhile, non-binary polar coding is suitable for short packet due to the higher reliability. Then, the mapping relations between non-binary polar coded alphabets and SCMA codewords should be considered. In this paper, two metrics are designed to optimize the mapping strategy. Simulation results show that the MSED codebook design method has good performance and a fine scalability. In addition, the mapping strategy further optimizes performance of the polar coded SCMA while ensuring the power equilibrium for each user’s output signal.