Exploiting Joint-Cache-Channel Coding for Decentralized Coded Caching With Heterogeneous Link Rates and Cache Sizes

Abstract

Coded caching can achieve significant caching gain by leveraging coded multicast for content delivery, which attracts great attentions in recent years. However, the coded multicast delivery design for decentralized coded caching with heterogeneous cache sizes and link rates is still an open problem. To this end, joint-cache-channel (JCC) coding is exploited in this paper. More specifically, a novel coded multicast delivery scheme that explores JCC coding is developed for the practical case with a finite number of packets per file. Instead of directly constructing the conflict graph at each packet level in existing studies, a packet-merging mechanism and a color-merging mechanism are developed to achieve the conflict graph in packet cluster level for coded multicast delivery so as to harvest the performance gain of JCC coding. The information-theoretic analysis of the transmission time via JCC coding is further conducted in the asymptotic regime when the number of packets per file approaches infinity, which provides the theoretical coded caching gain by JCC coding. Simulation results further show that compared to the existing method, the transmission time can be effectively reduced by our proposed scheme.