SWIPT enabled full-duplex overlay cognitive NOMA with hardware impairments

Abstract

Wireless system energy and spectrum efficiency can be increased by combining energy harvesting using cognitive radio with Non-orthogonal Multiple Access (NOMA) approaches. In this thesis, we analyze the performance of an overlay cognitive multiuser NOMA (OCNOMA) system in the presence of Hardware Impairments (HIs) on its transceiver nodes. The major transmitter's radio frequency signal is harvested by an energy-constrained full duplex secondary transmitter node, which then uses that energy to send its own unique communication signal using the NOMA technique in addition to relaying the primary information signal. We use the Spectrum Sharing Cooperation-Decode and Forward (SSC-DF) protocol for this purpose. Crucially, we take into account the effects of noisy signal processing caused by HIs and inadequate sequential interference cancellation in NOMA, both of them are inevitable in systems found in the real world. Additionally, we address the DPT (Direct Primary Transmission) scheme as a benchmark for evaluating the effectiveness of the full-duplex (FD) based cooperative spectrum sharing transmission (CSST) scheme. We uncover some relevant ceiling effects in the system by obtaining the mathematical equations of outage probability of the primary and secondary networks. In addition, we assess the energy efficiency and system throughput of the OCNOMA system under consideration. Our findings show off the advantages of the recommended SWIPT enabled FD CSST technique over the standard orthogonal multiple access and its half-duplex (HD) counterparts.