Joint Optimization of Cache Placement and Bandwidth Allocation in Heterogeneous Networks

Content caching at edge of the network has been considered as an effective way to reduce latency and alleviate burden on backhaul. In this paper, cache placement and bandwidth allocation strategies are jointly investigated in a multi-user system of a heterogenous network consisting of one macro base station and multiple small base stations. With the goal of minimizing outage probability, a simulated annealing algorithm-aided cache placement scheme along with an optimized bandwidth allocation via a dual decomposition method is proposed while taking into account the constraints of total available bandwidth, storage capacity of caching nodes, and fairness among users. Unlike previous works, the optimizations of the cache placement and bandwidth allocation are jointly considered in this paper. Meanwhile, in order to guarantee performance of each individual user while optimizing outage probability of the entire system, user fairness is taken into account as well. Simulation results show that, compared with other cache placement and bandwidth allocation schemes, the proposed method can obtain lower outage probability and maintain user fairness.