Coded caching with multiple file requests
Yi-Peng Wei, Şennur Ulukuş · 2017
We study a two-phase caching network consisting of one server with N files connected to K users through an error-free shared link. Each user has a cache memory which can store M files in the placement phase. In the delivery phase, each user requests L files, and the server transmits the messages accordingly. Using the message sent by the server combined with the cache memory, each user reconstructs the L files they requested. In this work, we focus on the case L > 1, i.e., the case of multiple file requests. We adopt the symmetric batch caching scheme and propose a general delivery scheme. To prove the optimality of the proposed general delivery scheme, we apply two converse techniques. The first converse technique is for general coding schemes and is obtained through virtual user construction. The second converse technique is for vector linear coding schemes and is obtained using an interference alignment point of view. With these two converse techniques, we characterize either the unconstrained optimal coding rate, or optimum linear coding rate, with symmetric batch caching for certain cases.