Packet-centric approach to distributed sparse-graph coding in wireless ad hoc networks

In this paper we present a packet-centric approach for distributed coding in decentralized wireless ad hoc networks, for applications in distributed data storage, data persistence and efficient data gathering. We study the setting where each of N network nodes generates an information packet and the goal is to efficiently encode information packets and disseminate produced encoded packets across the network in such fashion that gathering of any subset of slightly more than N encoded packets allows for retrieval of the original information. The process of distributed encoding is performed using packets that randomly walk over the network and sample information packets from network nodes, producing the encoded packets in a simple, elegant, fully decentralized and stateless way. The proposed scheme maintains properties of centralized codes in terms of performance parameters, offering at the same time advantage of robustness to node failures and changes in network topology. We specialize the proposed scheme for several important classes of low-complexity encodable/decodable sparse-graph codes – LDGM, LDPC (IRA), LT, and Raptor codes, evaluating its performance via simulation for various data-gathering scenarios.