Performance Analysis for Uplink NOMA System Based on Hybrid SIC Decoding Strategy

In this paper, based on an uplink two users NOMA (non-orthogonal multiple access) system, a hybrid SIC (successive interference cancelation) decoding strategy is proposed, in which BS (base station) adaptively select SIC decoding strategy according to channel station information (CSI) and QoS (quality of service) constrains. As we all know, determining the user's SIC decoding order based on QoS and CSI, have their own shortcomings, respectively. However, the proposed hybrid SIC decoding strategy can effectively overcome the shortcomings of the above two traditional strategies. Monte-Carlo simulations show that the hybrid SIC decoding strategy obtain better performance compared to two traditional strategies (CSI SIC decoding strategy and QoS SIC decoding strategy) and OMA (orthogonal multiple access) transmission mode. In addition, we also can see that, the power allocation coefficient has important impact on the ergodic capacity and outage probability of Un (near-end user) based on two traditional strategies. However, based on hybrid SIC decoding strategy, the change of the power allocation coefficient has little effect on the performance of Un. This shows that the proposed hybrid SIC decoding strategy has good robustness to the change of the power allocation coefficient.

I. Introduction

Non-orthogonal multiple access (NOMA) is considered to be one of the key technologies to improve the performance of the next-generation wireless communication networks [1], [2], which is mainly attributed to its higher spectral efficiency (SE) compared to orthogonal multiple access (OMA). MOMA mainly uses superposition coding (SC) to achieve differentiated power allocation accoring to channel state information (CSI) at the transmitting end, and uses successive interference cancelation (SIC) at the receiving end to decode user information [3].