Multiple Decision Aided Successive Interference Cancellation Receiver for NOMA Systems

Non-orthogonal multiple access (NOMA) is one of the critical technologies in fifth generation systems. Successive interference cancellation (SIC) is a typical solution of multiple users detection in NOMA systems. However, conventional SIC suffers from error propagation. To alleviate this problem, in this letter, a multiple decision SIC (MD-SIC) strategy is introduced. Instead of choosing one codeword for each user in traditional SIC detection, the proposed algorithm introduces multiple codewords as the candidates to combat the error propagation. Furthermore, a threshold is designed to control the size of candidate set for each user. It helps the MD-SIC to achieve a better tradeoff between performance and complexity. The simulation results indicate that the MD-SIC algorithm obviously outperforms the conventional SIC with a little additional computational complexity.