Sustainable Relay Selection Strategies via Auction Mechanisms in NOMA Cognitive Radio Networks for B5G Communications

ABSTRACT These days, wireless communication is facing the problems of short battery lifetime and lower capacity globally for Beyond 5G (B5G) communication. These problems can be addressed by proposing the advantages of nonorthogonal multiple access (NOMA)–based cooperative green cognitive radio networks (GCRNs) utilizing green secondary users (GSUs) as relays. For this, an auction market is designed with the composition of BS (auctioneer), GSUs (sellers), and PUs (buyers). The PUs must pay for the cooperative service provided by GSUs, while GSUs sell it for revenue. Moreover, PUs can adjust their bid according to their residual energy. Thus, less energy PUs have a higher chance of winning GSUs' service to prevent energy exhaustion. Meanwhile, GSUs reduce their ask price as per the amount of energy harvesting (EH). Hence, GSUs can serve more PUs if they harvest more energy from the received NOMA signal. Three auction rules impacting GSUs (as relay) selection are also being proposed. Finally, the simulation illustrates the diverse performance of three auction rules (with their merits and demerits) in selecting GSUs. Although all of them effectively enhance system capacity and extend the battery lifetime of PUs, with 0.01% battery energy consumption noticed in each second while transmitting 10 GB of data from the BS to the PUs.