Theoretical Analysis of Hybrid SIC Success Probability Under Rayleigh Channel for Uplink CR-NOMA

Abstract

In Cognitive Radio Non-Orthogonal Multiple Access (CR-NOMA), hybrid successive interference cancellation (SIC) was proposed to improve the probability for a secondary user to be served. It shifts the traditional focus on channel state information (CSI) to a quality of service (QoS) driven strategy, which matches cognitive radio philosophy. We present an analytical framework to theoretically study Hybrid SIC (HS) and Hybrid SIC with dynamic power control (HS-P) algorithms in terms of their probability of success under Rayleigh channel. Specifically, considering a CR-NOMA uplink system, we analyse the probability to allocate a primary and a secondary user into a radio resource, given their minimum QoS requirement. We obtain closed-form expressions for the mentioned algorithms and investigate the impact that the minimum QoS and the channel conditions have on the performance. Our analysis demonstrates that both algorithms share similarities in the way the primary user behaves, whereas they significantly differ in the secondary user’s case. Finally, we validate the correctness of the study by conducting Monte Carlo simulations using various system parameters. Our results show that our theoretical expressions closely match the simulated results in all testing scenarios. They appear promising to design advanced CR-NOMA features to enhance system performance based on success probability such as grouping algorithms.