Content Cache Placement for Scalable Video in Heterogeneous Wireless Network

To alleviate the pressure brought by the explosion of mobile video traffic on present cellular networks, small cell base stations (SBSs) with caching ability are introduced. In this letter, we consider the caching strategy of scalable video coding streaming over heterogeneous wireless network containing SBSs. We formulate an integer programming problem to minimize the average download time under the constraint of cache size at each SBS, and show that finding the optimal caching placement strategy is NP-hard. Heuristic solution was proposed based on the convex programming relaxation, which reveals the structural properties of cache allocation for each video. Simulation results demonstrate that our proposed caching strategies acquire significant performance gain compared with conventional caching policy.