Joint detection and decoding of polar-coded SCMA systems

摘要

Sparse-code multiple-access (SCMA) is a novel multiplexing method to increase the capacity of wireless communication systems. By giving users non-orthogonal codebook with few non-zero entries, the SCMA approach can highly improve the spectral efficiency, compared with traditional orthogonal ones such as CDMA, with tolerable detection complexity. Therefore, it has been considered as an option for 5G air-interface technique. Also essential in 5G, polar code has already been adopted by 5G eMBB control channel, for its capacity-achieving capability. In this work, a joint detection and decoding (JDD) method of polar-coded SCMA system is proposed for the first time, which can highly improve the performance of the polar-SCMA systems. By merging two factor graphs together, the intrinsic messages can be exchanged iteratively to help the likelihood messages converge. Numerical results have shown that, compared to separated detection and decoding (SDD), JDD can achieve remarkable performance gain little complexity overhead. Hardware architecture is also presented in this paper to demonstrate the feasibility of the proposed JDD scheme.