Neighbor discovery in delay tolerant networking using resource-constraint devices

In delay tolerant networking (DTN) nodes exploit their mobility in order to carry messages to their intended destination. Thus the knowledge of a node's neighbors over time, is a fundamental requirement for DTN nodes to exchange knowledge and messages. A typical problem in this task occurs when the neighboring nodes try to response to the neighbor discovery request initiated by a requesting node, during a fixed contention time window. In this paper a novel neighbor discovery protocol proposed for resource constraint devices (RFID tags) running according to the delay tolerant networking paradigm. The proposed protocol is based on the traditional P-Persistent CSMA algorithm, but with the addition of the sift-distribution (sift-Persistent) in order to reduce the collisions during the response phase. The proposal has been tested both in a simulator and in a real testbed under the OpenBeacon framework. Moreover, simulations and real testbed show a coherent behavior validating our proposal in the RFID context. Performance evaluations have been tested in terms of discovered neighbors.