Distributed Storage in Mobile Wireless Networks with Device-to-Device Communication

TL;DR

This paper explores how distributed storage with erasure coding in mobile wireless networks can reduce communication costs, especially when repairs are frequent and device arrivals are high, highlighting the effectiveness of MDS codes in this context.

Contribution

It introduces a repair scheduling framework for distributed storage in wireless networks and analytically evaluates its impact on communication costs, emphasizing the benefits of MDS codes.

Findings

Distributed storage reduces communication costs compared to base station downloads.

Frequent repairs and high device arrival rates further decrease costs.

MDS codes perform well in wireless distributed storage, contrary to classical settings.

Abstract

We consider the use of distributed storage (DS) to reduce the communication cost of content delivery in wireless networks. Content is stored (cached) in a number of mobile devices using an erasure correcting code. Users retrieve content from other devices using device-to-device communication or from the base station (BS), at the expense of higher communication cost. We address the repair problem when a device storing data leaves the cell. We introduce a repair scheduling where repair is performed periodically and derive analytical expressions for the overall communication cost of content download and data repair as a function of the repair interval. The derived expressions are then used to evaluate the communication cost entailed by DS using several erasure correcting codes. Our results show that DS can reduce the communication cost with respect to the case where content is downloaded only from the BS, provided that repairs are performed frequently enough. If devices storing content arrive to the cell, the communication cost using DS is further reduced and, for large enough arrival rate, it is always beneficial. Interestingly, we show that MDS codes, which do not perform well for classical DS, can yield a low overall communication cost in wireless DS.