Updating Content in Cache-Aided Coded Multicast

TL;DR

This paper introduces a novel cache-aided multicast scheme that leverages nearby caches to reduce delivery costs in dynamic, correlated data networks, without requiring the source to access past data.

Contribution

It proposes a decentralized cache design and update scheme compatible with existing network codes, optimizing multicast efficiency for dynamic, correlated data.

Findings

Caches significantly reduce multicast costs.

The scheme is compatible with any network code.

Simulation results validate the theoretical benefits.

Abstract

Motivated by applications to delivery of dynamically updated, but correlated data in settings such as content distribution networks, and distributed file sharing systems, we study a single source multiple destination network coded multicast problem in a cache-aided network. We focus on models where the caches are primarily located near the destinations, and where the source has no cache. The source observes a sequence of correlated frames, and is expected to do frame-by-frame encoding with no access to prior frames. We present a novel scheme that shows how the caches can be advantageously used to decrease the overall cost of multicast, even though the source encodes without access to past data. Our cache design and update scheme works with any choice of network code designed for a corresponding cache-less network, is largely decentralized, and works for an arbitrary network. We study a convex relation of the optimization problem that results form the overall cost function. The results of the optimization problem determines the rate allocation and caching strategies. Numerous simulation results are presented to substantiate the theory developed.