Cooperative Network Coding for Distributed Storage using Base Stations with Link Constraints

TL;DR

This paper introduces a cooperative network coding scheme for distributed storage in cellular networks with layered base stations, considering link constraints and costs, and derives optimal trade-offs and code constructions.

Contribution

It presents a new layered model for distributed storage with link constraints, deriving fundamental trade-offs and explicit optimal code constructions.

Findings

Derived closed-form expressions for storage and bandwidth costs at key operating points.

Established the fundamental trade-off between repair bandwidth cost and storage per node.

Provided an explicit optimal code construction for minimum storage regeneration.

Abstract

In this work, we consider a novel distributed data storage/caching scenario in a cellular setting where multiple nodes may fail/depart at the same time. In order to maintain the target reliability, we allow cooperative regeneration of lost nodes with the help of base stations allocated in a set of hierarchical layers. Due to this layered structure, a symbol download from each base station has a different cost, while the link capacities connecting the nodes of the cellular system and the base stations are also limited. In this more practical and general scenario, we present the fundamental trade-off between repair bandwidth cost and the storage space per node. Particularly interesting operating points are the minimum storage as well as bandwidth cost points in this trade-off curve. We provide closed-form expressions for the corresponding bandwidth (cost) and storage space per node for these operating points. Finally, we provide an explicit optimal code construction for the minimum storage regeneration point for a given set of system parameters.