Performance Analysis of a 5G Energy-Constrained Downlink Relaying Network With Non-Orthogonal Multiple Access

In this paper, a 5G energy-constrained network is considered, where a non-orthogonal multiple access (NOMA) scheme is applied at the multiple users. The outage probability and the ergodic rate are studied as two benchmarks to evaluate the system performance. First, a closed-form expression for the exact outage probability is derived. A lower bound of the outage probability is obtained and shown to predict well the system performance. In addition, the outage probability in the high signal-to-interference-plus-noise ratio (SINR) regime is studied to assess its upper limit while achieving the diversity order. Second, a closed-form expression for the upper bound of the ergodic rate is obtained. Then the ergodic rate in the high SINR regime is also analyzed. Finally, numerous computer simulations are performed to corroborate the superior performance of NOMA relative to orthogonal multiple access schemes and the validity of the derived analytical results.