Joint Optimization of Cooperative Coded Edge Caching and Task Offloading for Bi-directional Task Computing in Hierarchical Wireless Edge Networks

Abstract

To minimize the average processing latency of the bi-directional computation tasks in a hierarchical wireless edge network, where the input data of each task originates from both the local user devices and the remote cloud, the collaborative coded edge caching and task offloading schemes are jointly considered in this paper. The joint cooperative coded caching and task offloading decision-making problem is formulated as a non-convex non-linear integer programming problem, and thus is difficult to be solved in polynomial time. To efficiently solve the formulated problem, we adopt a two-step methodology, whereas the original optimization problem is decoupled into a cooperative coded edge caching subproblem and a bi-directional computation task offloading subproblem. An efficient alternating optimization algorithm is also proposed to optimize the caching and offloading decisions jointly. Extensive numerical simulations are carried out to demonstrate the convergence performance of our algorithm and confirm the effectiveness of the proposed algorithm in reducing the task processing delay and improving the cache hit ratio.