RDD: Repository-based Data Dissemination protocol for opportunistic networks

In opportunistic networks, mobile nodes such as mobile phones and PDAs use the mobility of devices in addition to wireless forwarding between intermediate nodes to facilitate communication without requiring a simultaneous path between source and destination.Without guaranteed connectivity, the strategy for forwarding messages has a significant effect on system performance. Most of the existing research work in opportunistic networking is based on the assumption that mobile nodes cooperate fully as data relays. In this paper, we present the design and evaluation of the Repository-based Data Dissemination (RDD) protocol. The protocol is based on the idea of exploiting well placed standalone fixed devices (named repositories) to facilitate data dissemination in opportunistic network environments where cooperation cannot be guaranteed. Our protocol uses push based communication where choice of the receiver depends on the interests and social behaviour of the users. The performance of the RDD is evaluated using simulation on real world traces. In comparison with epidemic routing, the results show that RDD with optimal location for repositories is able to drastically reduce resource consumption, especially in terms of message redundancy. At the same time, the RDD preserves the performance in terms of message delivery.