Proactive edge caching, as a promising approach to accommodate the explosively increased mobile data demand of Video on demand (VoD) service, has received extensive attention. However, although targeted to VoD service, existing caching policies are mainly designed for file downloading service while the unique requirement of quality of experience (QoE) for VoD service has been seldom considered. Aimed at maximizing the weighted average QoE of VoD service, this paper optimizes the proactive edge caching polices including the cached fraction and encoding bit rate of every video. We consider a two-tier network, where the helpers equipped with caching resource are deployed in the coverage area of traditional base stations. We formulate the caching optimization problems and show their hidden convexity properties, then we find that the optimal caching policy is determined by the weighted popularity-to-duration ratio of videos. Based on the result, we develop a low-complexity algorithm to find the optimal caching policy. Simulation results demonstrate evident performance gain of the proposed policy over the existing policy for VoD service.

中文翻译：

---

具有质量自适应的视频点播的主动边缘缓存

主动边缘缓存作为一种适应视频点播（VoD）服务爆炸性增长的移动数据需求的有前途的方法，受到了广泛的关注。然而，虽然针对VoD业务，现有缓存策略主要针对文件下载业务而设计，而很少考虑VoD业务对体验质量（QoE）的独特要求。本文以最大化VoD业务的加权平均QoE为目标，优化了主动边缘缓存策略，包括每个视频的缓存分数和编码码率。我们考虑一个两层网络，其中配备缓存资源的助手部署在传统基站的覆盖范围内。我们制定了缓存优化问题并展示了它们隐藏的凸性属性，然后我们发现最佳缓存策略是由视频的加权流行度与时长比决定的。基于结果，我们开发了一种低复杂度的算法来寻找最佳缓存策略。仿真结果表明，与现有的 VoD 服务策略相比，所提出的策略具有明显的性能提升。