Human Mobility and Message Caching in Opportunistic Networks

Opportunistic communication is one of the key technologies for advertisement, information sharing, disaster evacuation guidance in delay-tolerant networks (DTNs), vehicular ad hoc networks (VANETs) and so on. The efficiency of message delivery in opportunistic communication is correlated to the routing protocols and the movement pattern of mobile entities. In this paper, we focus on message delivery based on opportunistic communication by pedestrians who move based on Levy walk and Random walk movement patterns on the road network of a city. Moreover, we introduce roadside units located in the city, which play a role in the distributed message cache. So, we analyze the influence of roadside units, pedestrian walk patterns and the routing protocols of opportunistic communication on message delivery. We assume Random walk and Levy walk as pedestrian mobility models and Epidemic, Spray and Wait and PRoPHET as the routing protocols. Our simulation results clarify the difference of routing protocols and show that the roadside units have a significant impact on message delivery with a small number of pedestrians.