Non-orthogonal Multiple Access with SIC Error Propagation in Downlink Wireless MIMO Networks

Non-orthogonal multiple access (NOMA) is an emerging technology that can improve system spectral efficiency. In this paper, we propose a downlink multiple-input-multiple-output (MIMO) wireless system that incorporates NOMA. To make the system model more realistic, error propagation in successive interference cancellation (SIC) is considered during the decoding process. We formulate an optimization problem aiming at maximizing system throughput. The imposed error propagation increases the complexity to find a closed-form solution, so a heuristic way is proposed to solve the precoding matrix by an iterative algorithm. Case studies are performed to evaluate the impact of power allocation with residual interference afterwards. Simulation results show the superiority of the proposed precoding design and give an insight on power allocation.