Analysis of wireless message broadcast in large ad hoc networks of PDAs

We study the performance of message broadcasting in a real-world presence-awareness application using PDAs. Experimental data on the times needed to send and relay messages are analyzed from the perspective of the application and used to estimate the dependence of performance on the number of nodes. The results are then used to show that the introduction of a simple probabilistic method for controlling both the generation and rebroadcast of messages is sufficient to allow the application to be used in situations where there are large numbers of nodes.