Cache-Aided Modulation for Heterogeneous Coded Caching over a Gaussian\n Broadcast Channel

Abstract

Coded caching is an information theoretic scheme to reduce high peak hours\ntraffic by partially prefetching files in the users local storage during low\npeak hours. This paper considers heterogeneous decentralized caching systems\nwhere cache of users and content library files may have distinct sizes. The\nserver communicates with the users through a Gaussian broadcast channel. The\nmain contribution of this paper is a novel modulation strategy to map the\nmulticast messages generated in the coded caching delivery phase to the symbols\nof a signal constellation, such that users can leverage their cached content to\ndemodulate the desired symbols with higher reliability. For the sake of\nsimplicity, in this paper we focus only on uncoded modulation and\nsymbol-by-symbol error probability. However, our scheme in conjunction with\nmultilevel coded modulation can be extended to channel coding over a larger\nblock lengths.\n