Content caching is a widely studied technique aimed to reduce the network load imposed by data transmission during peak time while ensuring users’ quality of experience. It has been shown that when there is a common link between caches and the server, delivering contents via the coded caching scheme can significantly improve performance over conventional caching. However, finding the optimal content placement is a challenge in the case of heterogeneous users’ behaviors. In this paper we consider heterogeneous number of demands and non-uniform content popularity distribution in the case of homogeneous and heterogeneous user-preferences. We propose a hybrid coded–uncoded caching scheme to trade-off between popularity and diversity. We derive explicit closed-form expressions of the server load for the proposed hybrid scheme and formulate the corresponding optimization problem. Results show that the proposed hybrid caching scheme can reduce the server load significantly and outperforms the baseline pure coded and pure uncoded schemes and previous works in the literature for both homogeneous and heterogeneous user preferences.

内容缓存是一项广泛研究的技术，旨在减少高峰时间数据传输带来的网络负载，同时确保用户的体验质量。已经表明，当缓存和服务器之间存在公共链接时，通过编码缓存方案传递内容可以显着提高传统缓存的性能。然而，在异构用户行为的情况下，找到最佳内容放置是一个挑战。在本文中，我们考虑了同质和异质用户偏好情况下的异质需求数量和非均匀内容流行度分布。我们提出了一种混合编码-未编码缓存方案，以在流行度和多样性之间进行权衡。我们为所提出的混合方案推导出服务器负载的显式闭合表达式，并制定相应的优化问题。结果表明，所提出的混合缓存方案可以显着降低服务器负载，并且在同类和异类用户偏好方面均优于基线纯编码和纯未编码方案以及文献中的先前工作。