Computation Offloading Outage Probability Analysis and Min-Max Fairness Optimization in RIS-Assisted MEC System

Reconfigurable intelligent surface (RIS) is able to enhance the wireless channels, and further improve the performance in terms of outage in the mobile edge computing (MEC) system. Taking the computation offloading outage probability (COOP) as the metric, we investigate the coverage performance of the RIS-assisted MEC system. Specifically, we first obtain the closed-form expression of the COOP. Then we derive an asymptotic COOP expression at the high transmit power region and minimize the COOP in the single-smart device (SD) scenario. Finally, aiming at ensuring fairness among SDs in the multi-SD scenario, we propose an alternating optimization-based COOP min-max fairness (AOCMMF) algorithm to obtain the suboptimal solution of the nonconvex min-max problem. The simulation results verify that our closed-form and asymptotic expressions depict the COOP correctly. The proposed AOCMMF scheme can reduce the maximum COOP by 42.23% compared with the equal edge computing resource scheme, and the min-max fairness among SDs is realized.