Forwarding Strategy Selection in Dual-Hop NOMA Relaying Systems

Non-orthogonal multiple-access (NOMA) with perfect successive interference cancellation is an emerging research topic in the future wireless communication systems. In this work, NOMA is applied to dual-hop relaying systems, where the signals are transmitted with the aid of either decode-and-forward (DF) or amplify-and-forward (AF) relay. Exact expressions for outage probability and ergodic capacity are derived over independent Rayleigh fading channels, and a tight upper bound for the outage probability of AF scheme is provided. Based on the analysis, we study forwarding strategy selection for both fixed and optimized power allocation. The presented simulations verify the accuracy of the analysis, and the efficiency of the proposed forwarding strategy.