Storage-Repair Bandwidth Trade-off for Wireless Caching with Partial Failure and Broadcast Repair

TL;DR

This paper investigates the trade-off between storage capacity and repair bandwidth in wireless caching systems with partial node failures, demonstrating how broadcast repair can significantly reduce bandwidth requirements.

Contribution

It introduces a novel analysis of broadcast repair for partially failed cache nodes, deriving the storage-bandwidth trade-off in wireless caching environments.

Findings

Broadcast repair reduces repair bandwidth compared to unicast methods.

Utilizing surviving cache contents improves repair efficiency.

Theoretical trade-off curves are derived for various failure scenarios.

Abstract

Repair of multiple partially failed cache nodes is studied in a distributed wireless content caching system, where $r$ out of a total of $n$ cache nodes lose part of their cached data. Broadcast repair of failed cache contents at the network edge is studied; that is, the surviving cache nodes transmit broadcast messages to the failed ones, which are then used, together with the surviving data in their local cache memories, to recover the lost content. The trade-off between the storage capacity and the repair bandwidth is derived. It is shown that utilizing the broadcast nature of the wireless medium and the surviving cache contents at partially failed nodes significantly reduces the required repair bandwidth per node.