Throughput Performance of an Adaptive Power Splitting Relaying Protocol for Cooperative NOMA Networks

Abstract

The combination of Cooperative Non-Orthogonal Multiple Access (NOMA) and Simultaneous Wireless Information and Power Transfer (SWIPT) enhances the reception reliability and communication quality of users in wireless networks. However, conventional Fixed Power Splitting (FPS) protocol limits system performance due to its inability to adapts to fluctuating channel conditions. This strategy leads to decoding errors and reduces the rate of data transmission. This paper presents an Adaptive Power Splitting (APS) NOMA protocol for two-user SWIPT-based cooperative NOMA network. The adaptive strategy enables the near user to dynamically adjust its power splitting ratio based on real-time channel conditions to optimize Energy Harvesting (EH) and Information Decoding (ID). A system model was developed by incorporating a channel-based power splitter into the near user’s receiver architecture. The mathematical expressions for the Outage Probability (OP) and throughput for both users are derived over Rayleigh fading channels to evaluate the throughput performance of the proposed system. Performance analysis is conducted through MATLAB-based simulations, evaluating the effects of system parameters on the throughput performance of the considered system. The results reveal that at Signal-to-Noise-Ratio (SNR) of 25dB, APS NOMA system outperforms FPS NOMA and Orthogonal Multiple Access (OMA) by 13.33% and 29.66%, respectively, at near user, and by 4.74% and 30.38%, respectively, at the far user, validating its effectiveness for energy-constrained wireless networks and future IoT systems.