Performance Analysis of Mobile Edge Computing in Resource-Limited CSMA/CA Networks

Mobile Edge Computing (MEC) has proved its great potential for supporting the delay-stringent services in wireless networks. We notice that offloading performance of the MEC system is not only determined by the PHY-layer transmission rate, but also closely related to the performance of channel access and computation at the server. To this end, in this correspondence, we investigate a multiuser MEC system, where each user offloads packet to a single AP equipped with an MEC server by preempting the channel according to carrier sense multiple access with collision avoidance (CSMA/CA) protocol. We derive the effective offloading rate and delay by considering transmission outage caused by the poor channel condition, the MAC-layer channel competition, and the packet overflow due to the limited service capability of the server, where the service process is modelled as an $M/M/1/B$ queue. The theoretical analysis is verified by extensive simulations, which has shown that the competition intensity indicated by the number of users and the packet length, as well as the processing capability of the MEC server including the buffer size and the computation speed, has profound impact on the offloading performance.