Towards Practical File Packetizations in Wireless Device-to-Device Caching Networks

TL;DR

This paper introduces two combinatorial methods for D2D caching networks that significantly reduce packetization complexity while maintaining high throughput, and further enhances performance through spatial reuse.

Contribution

The paper proposes two novel combinatorial approaches, hypercube and graph-based, to reduce packetization in D2D caching networks while achieving comparable throughput.

Findings

Exponential reduction in packetizations compared to traditional schemes

Achieved high per-user throughput with reduced complexity

Spatial reuse further improves throughput in certain regimes

Abstract

We consider wireless device-to-device (D2D) caching networks with single-hop transmissions. Previous work has demonstrated that caching and coded multicasting can significantly increase per user throughput. However, the state-of-the-art coded caching schemes for D2D networks are generally impractical because content files are partitioned into an exponential number of packets with respect to the number of users if both library and memory sizes are fixed. In this paper, we present two combinatorial approaches of D2D coded caching network design with reduced packetizations and desired throughput gain compared to the conventional uncoded unicasting. The first approach uses a "hypercube" design, where each user caches a "hyperplane" in this hypercube and the intersections of "hyperplanes" represent coded multicasting codewords. In addition, we extend the hypercube approach to a decentralized design. The second approach uses the Ruzsa-Szem\'eredi graph to define the cache placement. Disjoint matchings on this graph represent coded multicasting codewords. Both approaches yield an exponential reduction of packetizations while providing a per-user throughput that is comparable to the state-of-the-art designs in the literature. Furthermore, we apply spatial reuse to the new D2D network designs to further reduce the required packetizations and significantly improve per user throughput for some parameter regimes.