Multi-Antenna Coded Caching for Shared Caches With Arbitrary User-to-Cache Association

Abstract

We consider the multi-antenna shared cache setup where the server is equipped with multiple transmit antennas and is connected to a set of users that are assisted with a smaller number of helper nodes. The helper nodes serve as caches that are shared among the users. Each user gets connected to exactly one helper cache. For this setting, under uncoded cache placement, an optimal multi-antenna coded caching scheme supporting all types of user-to-cache association is known in the literature which is applicable only when the number of antennas is at most the number of users connected to the least occupied cache. The other known multi-antenna shared caching schemes considered only uniform association of users to helper caches. In this work, we propose a multi-antenna coded caching scheme for the shared cache setting with more diverse user-to-cache associations where the number of antennas is not less than the number of users connected to the least occupied cache. Under certain scenarios, our scheme achieves the same performance exhibited by some optimal schemes.