Relay Selection in NOMA-Based Cooperative Wireless Backhaul Networks

The joint application of wireless backhaul networks and non-orthogonal multiple access (NOMA) hold the potential to fulfill the increasing demands of fifth-generation (5G) communication networks and beyond. It is usual in wireless backhaul networks to take assistance from small cell base stations acting as intermediate relays to reach the remote destination. This cooperative communication is an acknowledged technique to combat multi-path fading, improve energy efficiency, and enhance the reliability and capacity of wireless networks. This article studies the application of relay selection (RS) in the proposed NOMA-based cooperative wireless backhaul network model. The system performance is analyzed through closed-form and asymptotic expressions of the sum ergodic rate. The paper also presents practical design guidelines of optimum location for small base stations of wireless backhaul networks.