Wireless Distributed Storage in Socially Enabled D2D Communications

Wireless distributed storage systems can potentially relieve the centralized traffic burden of base stations (BSs), and further improve system reliability for content sharing in device-to-device (D2D) communications. Mobile devices [i.e., content requesters (CRs)] can not only download their desired contents from serving BSs, but can also get them from neighboring devices [i.e., content helpers (CHs)] with possession of the contents. However, D2D links between CRs and CHs are not necessarily stable, due to user mobility and the time-varying property of wireless links. This paper focuses on the utilization of socially enabled D2D links to deliver the desired contents based on distributed storage. We evaluate the success rate for downloading and repairing in D2D-assisted networks accordingly, by analyzing statistic social interaction information for potential D2D links. Thus, it is necessary to maintain or assign enough qualified D2D links to afford content downloading and repairing from neighboring devices. To reduce the overall system transmission cost, this paper further proposes a hierarchical bi-partite method to guarantee at least k admissible D2D links according to their statistical channel state information, by considering one type of erasure correcting codes, the maximum distance separable code. Simulation results demonstrate the performance and advantage of our proposed scheme.