Service Placement and User Assignment in Multi-Access Edge Computing with Base-Station Failure

Multi-access edge computing (MEC) enables users to exploit the resources of cloud computing at a base station (BS) in proximity to the users where an MEC server is hosted. While we have advantage of being able to communicate with low latency and small network load in MEC networks, the resources in BSes are limited. One challenge is where to provide users with services from to make efficient use of resources. Furthermore, to enhance the reliability of MEC system, the case that a BS fails needs to be considered. This paper proposes a service placement and user assignment model with preventive start-time optimization against a single BS failure in MEC networks. The proposed model preventively determines the service placement and user assignment in each BS failure pattern to minimize the worst-case penalty which is the largest penalty among all failure patterns. We formulate the proposed model as an integer linear programming problem. We introduce two algorithms, one is the greedy algorithm with allocation upgrade and the other is with allocation upgrade and preemption, to solve the problem. The results show that the introduced algorithms obtain a solution with the smaller worst-case penalty than the benchmark in a practical time.