Ubiquitous access to distributed data in large-scale sensor networks through decentralized erasure codes
Consider a large-scale wireless sensor network of n nodes, where a fraction k out of n generate data packets of global interest. Assuming that the individual nodes have limited storage and computational capabilities, we address the problem of how to enable ubiquitous access to the distributed data packets. Specifically, we assume that each node can store at most one data packet, and study the problem of diffusing the data so that by querying any k nodes, it is possible to retrieve all the k data packets of interest (with high probability). We introduce a class of erasure codes and show how to solve this problem efficiently in a completely distributed and robust way. Specifically we show that we can efficiently diffuse the data by "pre-routing" only O(ln n) packets per data node to randomly selected storage nodes. By using the proposed scheme, the distributed data becomes available "at the fingertips" of a potential data collector located anywhere in the network.