Layer-aware Interference Mitigation Scheme for Downlink Multi-User SCMA System

Sparse code multiple access system with multiple antennas offers unprecedented massive connectivity and capacity. To reduce the interference in a downlink multiple user SCMA (MU-SCMA) system, we propose a layer-aware interference mitigation scheme (L-AIMS). Firstly, preprocess the codewords of paired users to mitigate the intra-layer interference. Secondly, adopt the generalized singular value decomposition to mitigate the inter-user interference. Then, we obtain the adjusted rate of paired users with L-AIMS. The simulation results show that the proposed L-AIMS can improve the sum rate of paired users and the adjusted rate of the user with bad channel condition compared with the original scheme.