Best User Selection for NOMA-Aided Full-Duplex Cooperative D2D Communication System

Full-duplex (FD) and device-to-device (D2D) communication are emerging as a prominent technology for the fifth-generation (5G) and beyond cellular networks. This paper proposes the best-user selection scheme for non-orthogonal multiple access (NOMA) aided FD cooperative D2D (C-D2D) communication system. According to this scheme, among all available FD-D2D user pairs, the D2D source (S) that can achieve the largest signal-to-interference-plus-noise ratio (SINK) improvement of cellular transmission is selected to share the cellular spectrum. A self-interference suppression (SIS) technique is used at the FD node to cancel self-interference (SI). In addition, a power splitting protocol is employed using NOMA to divide resources between the cellular uplink and the D2D link transmission. Further, successive interference cancellation (SIC) is used at the D2D receiver (D) to decode the signals. The analytical expressions for achievable rates of the cellular and D2D links and their outage probabilities are derived. Results show that the proposed scheme suggests the choice of optimal values for parameters such as the power splitting factor and the SIS parameters (/3 and A) to improve the performance of the cellular and D2D users.