Probabilistic Routing with Multi-Copies in Delay Tolerant Networks

Intermittently connected mobile networks don´t have a complete path from a source to a destination at most of the time. Such an environment can be found in very sparse mobile networks where nodes meet only occasionally or in wireless sensor networks where nodes sleep most of the time to conserve energy. Current approaches in such networks are primarily based on two kinds of transmissions: multi-copy flooding scheme and single-copy forwarding scheme. However, they have either high overheads due to excessive transmission or long delays due to the possible incorrect choices during forwarding. In this paper, we propose a hybrid probabilistic routing algorithm using multi-copies called HUM, in which a packet is initially replicated to a certain number of nodes, which sequentially forward those packets to the destination node based on a probabilistic routing scheme. Simulations show that compared to Epidemic routing, Spray and wait routing, HUM routing scheme provides a nearly optimal delay performance with a stable packet arrive rate with the community mobility model.