Performance Analysis of a CR‐Enabled Energy‐Efficient Device‐to‐Device Network With Ambient Backscattering and NOMA

ABSTRACT A cooperative device‐to‐device (D2D) communication system with cognitive radio (CR) enabled that integrates ambient backscattering (AB) and energy harvesting is studied in this paper. Cellular network (CN) resources are exploited by D2D users. The transmission between source and destinations is hybrid (overlay or underlay) based on sensing information. In overlay, cellular users (CUs) are absent in the given channel; thus, relay transmits with high power based on available harvested energy. On the other hand, in underlay CUs are present, and they communicate with each other via base station (BS); thus, in D2D network, relay transmits with controlled power using nonorthogonal multiple‐access (NOMA) technique. In contrast to the conventional hybrid transmission, in the proposed work, relay adopts the ambient backscatter communications (ABCs) in underlay because RF signal of BS is available. The relay first backscatters the source information using available RF signal of BS; thereafter, it uses its own battery for controlled transmission and keeps the interference to the CU receiver within a tolerable limit. Spectrum sensing (SS) and a transmit power limitation are taken into consideration while developing analytical models for throughput, outage, and energy efficiency (EE). An algorithm is proposed to optimize the relay transmit power in the underlay scenario. Through meticulous simulation, the network performance in terms of throughput, outage, and EE is examined for hybrid transmission with ABCs.