Repairable Fountain Codes with Unequal Locality for Heterogeneous D2D Data Storage Networks

In this paper, we consider a problem about a novel distributed erasure code, named repairable fountain code (RFC), used in heterogeneous networks (HetNets) including different micro base station (MBS) coverage areas, for data storage and delivery among the devices connected by D2D links. The system model of three-tier MBS distributed data storage network is presented and the basic principle is also detailed illustrated. Then, the downloading and repairing communication costs of RFC are analyzed based on its rateless, systematic and lower locality properties. Particularly, the unequal repair locality of RFC (URL-RFC) is designed and discussed for the adaption to the different mobilities with the Poisson process of the nodes in three MBS coverages, and to further reduce the energy cost. The simulation results show that, the URL-RFC scheme we proposed can obtain the lowest cost performance in the case of instantaneous repair, and the cost of URL-RFC is larger than that of RFC when the repair interval is also larger, but it will finally approach to the RFC communication cost curve.