Design on Polarization Weight-Based Polar Coded SCMA System over Fading Channels

Abstract

Sparse code multiple access (SCMA) is one of the key techniques to address the high spectral efficiency and massive connectivity requirements for the fifth generation (5G) wireless systems. Moreover, polar codes are selected as the candidate scheme of control codes in enhanced mobile broadband (eMBB). Note that the joint design of channel coding and SCMA scheme can significantly improve the system overall performances, which essentially shows the potential for 5G massive machine type communications (mMTC). Thus, in this paper, we proposed a polarization weight (PW)-based polar coded SCMA (PC SCMA) system to satisfy the requirements of low complexity implementation and high reliability under a wide range of code length and rate. Our design of PW-based PC SCMA system is mainly including the following three aspects: 1) deploy the polarization weight (PW) algorithm to construct polar code with lower complexity; 2) employ the bit-reverse shortening (BRS) algorithm to achieve rate matching in the encoding part; 3) adopt the cyclic redundancy check (CRC) to set up an early stopping criterion in the decoding part. Simulation results show that the proposed PW-based PC SCMA system can outperform the existing PC SCMA system over AWGN and fading channels.