Ergodic sum capacity analysis of NOMA‐SWIPT enabled IoT relay systems

Instead of using the participating relay node only for relaying the data of the source node, in this letter, we have also considered transmitting the data of the IoT relay node (IoTR) along with the source node data based on time switching (TS), power splitting (PS) relaying and NOMA. Therefore, in this context, we investigate the ergodic sum capacity (ESC) analysis of simultaneous wireless information and power transfer (SWIPT) based non‐orthogonal multiple access (NOMA) for the Internet of Things (IoT) relay systems. Furthermore, we also study the effect of both perfect successive interference cancellation (pSIC) and imperfect SIC (ipSIC) on the proposed system. Analytical expressions for the ESC under both pSIC and ipSIC scenarios are mathematically derived and corroborated through Monte‐Carlo simulations. Our result demonstrates that the PS relaying with NOMA is more energy‐efficient than TS relaying with NOMA for the proposed system.