A Two-stage Adaptive Weight-adjusting Interference Cancellation Demodulation Technology Based on SLIC and CWIC for NOMA

Abstract

Gbps business will become an important part of the future mobile communications systems. It has been shown that non-orthogonal multiple access (NOMA) based on power multiplexing could potentially offer a robust performance in the spectrum utilization efficiency. However, when the terminal performs demodulation, the difference in user power superposition and the non-uniformity of user distribution may lead to some severe problems such as intensive excessive power or insufficient signal-to-noise ratio (SNR) under different scenarios, the performance of the communication system is reduced. Therefore, in this paper, a two-stage adaptive weight-adjusting interference cancellation (AWIC) demodulation technology based on symbol level based interference cancellation (SLIC) and code word level interference cancellation (CWIC) has been developed and presented. Moreover, we analyzed the downlink transmission performance of NOMA, innovated the multi-stage adaptive weight-adjusting serial interference cancellation (SIC) demodulation technology, and adjusted the depth of the demodulation algorithm according to the posterior decoding performance feedback. It improves NOMA demodulation performance under a low SNR environment and reduced the complexity under a high SNR environment. According to the computer simulations, under the average bit error rate (BER) of $3\times 10^{-2}$, the improved NOMA interference cancellation approach proposed in this paper has a 5.09 dB performance improvement compared to SLIC and 9.8 dB compared to CWIC.