JoWUA

Abstract

This article addresses the issues of counting the number of nodes in opportunistic mobile networks (OMNs). The global knowledge of network size is commonly required to design optimal routing algorithms in OMNs. However, due to the inherent characteristic of long transfer delay, node counting in such intermittently-connected networks is a challenging task. In this paper, we propose the Mark- Recapture method to estimate the number of nodes in a network. In ecology, the statistical technique has been widely used to predict the population sizes of animals in open areas. The scheme initially samples nodes in the network, and an estimate of the network size is then calculated based on this partial knowledge of the network. Through extensive simulations driven by random movement and realistic mobility models, we show that the proposed method is able to produce a good estimate of network size within a relatively short duration of time. Finally, by tweaking Epidemic routing with the local estimate of network size, we can reduce the delivery cost of this flooding strategy without significantly degrading the overall network delivery performances.