Analysis of Geographic DTN Routing under Random Walk Mobility Model

In this paper, we derive the average and the distribution of message delivery delays in a geographic DTN routing with multiple mobile agents, whose mobility patterns are given by random walks on a graph and message routing algorithm is FIFO (First-In First-Out) algorithm. A geographic DTN routing aims at realization of message delivery among multiple (generally, geographically-dispersed) geographic locations on a field without necessity of specific communication infrastructure by utilizing mobility of mobile agents. We model the behaviors of mobile agents as multiple random walks on a graph. In this paper, two types of workload models - one-time workload model (i.e., simultaneous generation at the initial state) and continuous workload model (i.e., Poisson message arrival) - are considered. Our analysis reveals the effect of system parameters - the number of mobile agents on the field, the number of message loadings at a geographic location, the message generation rate and the number of message replicas - on the average and the distribution of message delivery delays. We also discuss the feasibility of a specific application of geographic DTN routing - communication among evacuation sites in disaster area.