无人机辅助5G网络中基于合同的缓存租赁机制

Contract-Based Cache Renting Mechanism in UAV-Assisted 5G Networks

为了缓解回程链路的压力,移动网络运营商(MNO)在其宏基站(MBS)覆盖范围内的热点地区上方灵活部署具有缓存能力的无人机(UAVs)作为空中基站.此外,多个内容提供商(CPs)渴望租用MBS和UAVs的缓存空间以主动缓存其流行视频,从而降低订阅用户的服务时延.但每个CP租赁缓存空间的意愿程度是私有的,这导致MNO和CPs间的信息不对称.为了解决此问题,提出了基于合同理论的缓存资源租赁机制以最大化MNO的效用.理论上推导出了合同的可行条件,继而将目标优化问题放松为凸规划问题,采用KKT条件求得缓存租赁的最优合同.仿真结果验证了所提出的无人机辅助第5代移动通信系统(5G)网络缓存租用机制的有效性,并讨论了UAVs的飞行高度对系统性能的影响.

To alleviate the load of the backhaul link,a mobile network operator(MNO) temporarily deploys cache-enabled unmanned aerial vehicles(UAVs) as aerial base stations to offload the traffic from a macro base station(MBS). While several content providers(CPs) desire to rent the cache space at both the MBS and UAVs to proactively place their popular videos so that their subscribers can receive low-latency services. However,the willingness for cache renting is privately for each(CP),resulting in asymmetric information between the MNO and CPs. To overcome this problem,the contract theory is exploited to formulate the cache renting problem and to maximize the utility of MNO. The feasible conditions for the contract are derived,and the target optimization problem is relaxed to the convex programming problem.Finally,the KKT condition is utilized to solve the optimal contract for the cache renting. Experiments validate the effectiveness of the proposed cache renting mechanism in UAV-assisted the 5 th generation of mobile communications system(5G) networks,and the influence of UAVs’ flight altitude on system performance is discussed.