User selection schemes for energy constrained SWIPT assisted CNOMA communication under Nakagami- fading

User selection significantly influences the efficiency and reliability of cooperative non-orthogonal multiple access (CNOMA) systems, particularly when nodes operate under radio frequency energy harvesting (RFEH). This study investigates RFEH-enabled CNOMA networks, with and without simultaneous wireless information and power transfer (SWIPT), to assess the impact of various user selection strategies under energy constraints. The system comprises a base station (BS), multiple near users, and one far user, where near users harvest energy via SWIPT and assist the far user using amplify-and-forward (AF), decode-and-forward (DF), or hybrid AF/DF relaying. The BS transmits a superimposed signal, and the selected near user performs successive interference cancellation to decode its data and forward the far user ‘s information using harvested energy. System performance over Nakagami-m fading channels is analysed in terms of outage probability, throughput, and energy efficiency, with MATLAB simulations identifying the optimal relaying and user selection combination for energy-constrained SWIPT-assisted CNOMA systems.