Joint Optimization on Cache Size and File Placement in Backhaul Limited Dense Networks

Abstract

Backhaul capability is usually considered as a bottleneck for system performance in dense wireless networks, caching popular file in base stations is an effective solution. In the dense deployed network, it is necessary to consider the interaction between cache size and file placement, which will lead to a rise of cache deployment cost. In order to solve this problem, this paper introduces the concept of user group and proposes a scheme with joint optimization of cache size and file placement. In this scheme, considering constraint of file delivery latency and other factors, joint optimization for minimizing the total cache size is established, with iteration of the coordinate axis descent algorithm and cache value competition algorithm. Simulation results show that, compared with the greedy algorithm, the proposed algorithm can effectively reduce the total cache size and and is very close to the optimal algorithm. Influences of user group size and preference on file placement are also discussed.