Coded Caching with Heterogeneous User Groups

Coded caching is a promising technique to reduce the backbone load in content requesting and delivery networks. In conventional setup, users are assumed to be homogeneous such that all users cache the files in a same manner, i.e., for any two users, they cache the files according to the same distribution, which could be a uniform caching distribution or a nonuniform one. However, in the perspective of video service providers, it's necessary to offer better service for paying subscribers or VIP users, compared to normal users, to decrease the network load. In this paper, a more general and practical case with heterogeneous users is investigated. Users are classified as two groups in a manner that is independent of files, say VIP and non-VIP group. We would like to see how coded caching performs to ensure the users in VIP group have a better experience than those in non-VIP group. These two user groups are considered with nonuniform and uniform caching distributions, respectively. A heterogeneous caching and delivery scheme is proposed and the associated upper bound on the achievable rate is obtained with the robustness of fractions of the two groups. Simulation results confirm the robustness of our theoretical results and show that the VIP group could have better experience than the non-VIP group.