Analysis of the OutagePerformance of Energy-Harvesting Cooperative-NOMA System with Relay Selection Methods

In this paper, we propose a cooperative Non-Orthogonal Multiple Access (NOMA) transmission scheme with energy-harvesting, employing channel estimation to obtain accurate Channel State Information (CSI) through the Least Squares (LS) channel estimation procedure. The objective is to establish an optimal communication path between the source and the destination. To achieve this, we compare the performance of two relay selection methods: Optimal Relay Selection (ORS) and Max-Min Relay Selection (MMRS). We analyze the impact of the number of relays and the power allocation factor on the system's performance, specifically focusing on the outage probability expressions. Furthermore, we compare cooperative-NOMA with cooperative relaying without NOMA. Numerical and simulation results confirm that the cooperative-NOMA system outperforms the traditional relaying system without NOMA. Additionally, ORS demonstrates superiority over MMRS in terms of the outage performance.