Collaborative Online Edge Caching With Bayesian Clustering in Wireless Networks

摘要

In this article, we study the edge caching problem by considering the heterogeneous context with unknown users' preferences. The cache provider (CP) can personalize the users' storage based on available data to maximize the overall cache hit rate, accounting for the dynamic natures of both mobile edge cache scenarios and the users' preferences. Toward this end, we introduce an online Bayesian clustering caching algorithm for the CP to autonomously learn the users' interactive cache hit data in a collaborative way while maintaining sustainable scalability. Specifically, a Bayesian generative framework called the Dirichlet multinomial mixture (DMM) model is used to describe the uncertainty about the latent number of users' clusters, each of which consists of the users with the same preference. Then, a dynamic clustering policy is proposed to obtain both the underlying mapping of users to clusters and the preferences of each cluster by using a collapsed Gibbs sampling algorithm. Subsequently, cache decisions are made according to the generated mappings by extending the traditional cache bandit algorithm to a new bandit mechanism with clusters of arms, capable of expediting the learning process between the exploitation and exploration. We theoretically characterize the value of dynamic Bayesian clustering for the long-term edge caching scenario with respect to the regret incurred by the noncluster schemes. Finally, using a real-world data set, our numerical results show that the proposed scheme outperforms the caching algorithms without clustering in the uncertain network scenario.