PSR versus TSR Relaying Protocols: Leveraging Full-Duplex DF and Energy Harvesting for SWIPT in NOMA Systems

This study introduces a cooperative non-orthogonal multiple access (NOMA) system designed for simultaneous wireless information and power transfer (SWIPT), incorporating a relay node operating in full-duplex (FD) communication mode. The system employs two protocols: power-splitting relaying (PSR) and time-switching-based relaying (TSR), catering to both delay-limited and delay-tolerant transmission modes. These protocols aim to optimize energy harvesting and information processing at the relay user. The paper provides closed-form expressions for performance metrics and investigates the impact of key parameters. Our findings indicate that the NOMA scheme consistently achieves a lower outage probability (OP) in comparison to conventional orthogonal multiple access (OMA) schemes. Furthermore, PSR surpasses TSR in both low and high signal-to-noise ratio (SNR) regions with respect to throughput (TP), ergodic rate (ER), and energy efficiency (EE). The integration of energy harvesting (EH) into NOMA has been demonstrated to significantly enhance EE.