TR-IIS-07-009    Fulltext

As the number of opportunistic networking applications continues to surge, the need for an effective routing scheme that can accommodate the various types of intricate behavior observed in opportunistic networks is becoming increasingly urgent. In this paper, we propose the HEC-PF scheme, an enhancement of our previous H-EC scheme for effective data forwarding in opportunistic networks. The enhanced scheme modifies the aggressive forwarding phase of the H-EC scheme by implementing a new Probabilistic Forwarding feature, which decides whether to forward a message to a newly encountered node based on the delivery probability. Using simulations as well as realistic network traces, we evaluate the performance of the proposed scheme in terms of delivery latency and completion ratio. The results show that the HEC-PF scheme outperforms the EC and H-EC schemes in all test cases, and the performance gain is even more substantial when network connectivity is extremely poor. By varying the parameters of the HEC-PF scheme, we show that its completion ratio improves as the maximum forwarding distance or the hop distance considered when calculating the delivery probability increases. The effectiveness of the HEC-PF scheme makes it an ideal solution that goes a long way toward ensuring effective data delivery in opportunistic networks.

Keywords: Opportunistic Networks; Routing; Probabilistic Forwarding; Erasure Coding; H-EC Data Forwarding