Time Shared Half/Full-Duplex Cooperative NOMA With Clustered Cell Edge Users

This letter proposes time sharing (TS)-based half/full-duplex (HD/FD) cooperative non-orthogonal multiple access (CRNOMA) schemes, namely, TS-HD-CRNOMA and TS-FD-CRNOMA to efficiently utilize the spectrum of unpaired users. A scenario with more cell edge users (CEUs) than cell center users is considered. Both schemes pair a CCU with multiple clustered CEUs in a TS fashion via a relay, thereby efficiently utilizing the frequency bands of multiple CEUs, which may remain underused in conventional CRNOMA. Ergodic sum capacity of the schemes is analytically derived, validated through simulations, and compared with conventional multiple access schemes to show the achieved capacity gains.