Research on Cooperative Caching Strategy in 5G-Satellite Backhaul Network

Abstract

With the advantage of stable communication links and broadcast coverage, satellites play an irreplaceable role in terrestrial-satellite integrated system nowadays. However, when taking consideration of satellite transmission in backhaul link, it will cost a long time due to its high altitude. As we know, 5G network will be deployed in 2020 with the requirements of higher capacity and lower latency. Thus, how to reduce the delay of transmission in 5G-satellite backhaul link after users’ request is the research we discussed. Caching is considered an efficient and time-saving technique in terrestrial communication networks. Based on this reference, a cooperative caching strategy is proposed in this paper where caches can be placed at macro-micro cells deployed on the ground as well as satellite. Our target is to minimize the average latency of users during the requested files transmitting between satellite and ground. Then, we formulate the cooperative caching optimization problem as a NP-Hard problem. Furthermore, to avoid meeting premature convergence, the proposed optimized cooperative caching strategy is based on simulated annealing algorithm to carry out the caching allocation efficiently. The simulation results demonstrate that the proposed caching strategy can improve the performance of users’ QoS.