  Recently coded caching has emerged as a promising means to handle
continuously increasing wireless traffic. However, coded caching requires users
to cooperate in order to minimize the overall transmission rate. How users with
heterogeneous preferences cooperate in coded caching and how to calculate the
resulting caching gains are still open problems. In this paper, a two-phase
cache-aided network is investigated, in which users with heterogeneous
preferences are served by a base station through a shared link. Effective
throughput is considered as a performance metric. It is proved that the
achievable domain of effective throughputs is a convex set and can be
characterized by its boundary. A special type of caching schemes, named uncoded
placement absolutely-fair (UPAF) caching, is studied. For the two-user case,
games are formulated to allocate effective throughput gains for the two users.
For the general multiuser case, a UPAF policy is proposed to organize user
cooperation. It is shown that users with more concentrated preferences can
obtain higher effective throughputs.
