Caching frequently requested contents at fog nodes has been proposed to alleviate the unprecedent pressure of limited backhaul capacity and decrease latency. However, due to the broadcast characteristic of wireless communication and limited resource, how to ensure information security is of vital importance. Compared with traditional encryption method, physical layer security has advantages on low computing complexity and resource consumption. In this paper, aiming at maximizing secrecy throughput, the Wynar’s encoding method is adopted to ensure communication security by jointly optimizing the caching placement strategy and secrecy rate. Numerical results have demonstrated that the proposed security aware caching placement strategy can outperform the other two baseline algorithms and achieve the tradeoff between diversity and security in cooperative networks.

已经提出在雾节点处缓存经常请求的内容以减轻有限的回程容量的空前压力并减少等待时间。然而，由于无线通信的广播特性和资源有限，如何确保信息安全至关重要。与传统的加密方法相比，物理层安全性具有计算复杂度低和资源消耗低的优点。本文针对最大化保密吞吐量，采用Wynar编码方法，通过共同优化缓存放置策略和保密率来确保通信安全。