Locus: a location-based data overlay for disruption-tolerant networks

Embedded sensors in mobile devices such as cars and smart phones present new opportunities to collect location-specific data about an environment. This data can be used to enable new real-time location-based applications. A major challenge is efficiently collecting, storing and sharing the data. This paper proposes Locus, a location-based data overlay for DTNs. Locus keeps objects at specific physical locations in the network using whatever devices currently are nearby. Nodes copy objects between themselves to maintain the locality of data. Location utility functions prioritize objects for replication and enable location-based forwarding of data look-ups. As a first-of-its-kind application, Locus is compared against other possible replication policies and shown to achieve query success rates nearly 4 times higher than other approaches.