Effective Resource Utilization Schemes for Decode-and-Forward Relay Networks With NOMA

This paper investigates an effective resource utilization scheme for the decode-and-forward (DF) cooperative relaying networks (CRNs) with non-orthogonal multiple access (NOMA). Considering a T time slots transmission, the proposed effective resource utilization scheme adopts max-min relay selections to satisfy the quality-of-service (QoS) and provide a higher priority. Unlike the conventional CRNs, to improve the system performance and resource utilization, the unselected relays will continue receiving the signals transmitted by the base station (BS), as well as the selected relays forward the decoded signals to the user equipment (UE). Moreover, the maximum ratio combining (MRC) is utilized at the UE to jointly detect the receptions for each time slot. The achievable average sum-rate (SR) of the proposed system is analyzed for independent Rayleigh fading channels, and the asymptotic expressions are also provided. The qualitative numerical results corroborating our theoretical analysis show that the proposed effective resource utilization scheme significantly improves the transmission rate and SR performance in comparison to the conventional CRN-NOMA schemes.