A Novel Framework in MIMO Downlink Transmission with Non-orthogonal Multiple Access

Abstract

Sparse code multiple access (SCMA) technique is being noted as one of the promising non-orthogonal multiple access technologies for the fifth generation (5G) wireless communications. Due to the code-domain multiplexing and message passing algorithm (MPA) implementing at the receiver, SCMA technique shows high spectral efficiency and good performance. However, when combining multiple-input multiple-output (MIMO) technique in downlink scenario with SCMA, the performance of these existing schemes are not satisfactory with high complexity. In this paper, we propose a novel framework for MIMO downlink transmission based on the combination of SCMA and MIMO technique to significantly improve the spectrum efficiency and guarantee the performance. The simulation results show that the proposed scheme achieves significant spectral efficiency improvement and provides satisfactory performance when combining SCMA and MIMO together.