Performance analysis of cooperative NOMA based intelligent mobile edge computing system

In this manuscript, a cooperative non-orthogonal multiple access based intelligent mobile edge computing (NOMA-MEC) communication system is constructed in detail. The nearby user is viewed as a decoding and forwarding relay, which can assist a distant user in offloading tasks to the intelligent MEC server. Then, the closed-form expressions of offloading outage probability for a pair of users are derived in detail to evaluate the performance of the cooperative NOMA-MEC system. Furthermore, the approximate expressions of offloading outage probability are provided in the high signal-to-noise ratio region. Based on the asymptotic analyses, the diversity order of distant user and nearby user is n+m+1 and n+1, respectively. The system throughput and energy efficiency of cooperative NOMA-MEC are analyzed in delay-limited transmission mode. Numerical results show that 1) Cooperative NOMA-MEC is better than orthogonal multiple access (OMA) in terms of offload performance; 2) The offload performance of cooperative NOMA-MEC system improves as the number of transmission task decreases; and 3) Cooperative NOMA-MEC performs better than OMA in energy efficiency.