Cache-assisted interference cancellation in the multi-user downlink fading channel and its application in HetNets

Abstract

Next generation wireless systems will be characterized by two things among others: the dense deployment of small cell base stations (SBS), and caching of popular data files at the edge. In this paper we study the downlink multi-user fading channel in a small cell when the interfering transmissions from another non-cooperative BS are files characterized by asynchronous reuse, that is the same file is transmitted several times depending on its popularity. For this system model we propose cache-assisted successive interference cancellation (CAIC): The small cell users cache popular files, and then for decoding the desired file from the SBS they use the cached data for canceling the interfering transmissions of the interfering BS. The result in this case is an interference-free point-to-point link. For this system we develop an analytical model for the ergodic capacity (fast fading) and outage probability (slow fading) of the multi-user channel from the SBS towards its users. Next, we validate our analytical tools with simulation and experiments, and finally we apply CAIC in HetNets where we show the significant performance improvements that it offers. © 2019