Performance issues in content dissemination to metropolitan mobile users

Abstract

In this paper we consider a set of heterogeneous terminals in a urban area that are interested in collecting the information originated from several sources. This set includes mobile nodes (pedestrian and vehicles) and fixed terminals. In particular, each terminal aims at retrieving the data items in a limited region of interest (ROI) centered around the node position. Since data items may change over time all nodes must strive for having access to the latest version. The goal of the paper is to evaluate the amount of information each node is able to gather (coverage) resorting to simple distributed data collection and sharing through local broadcast communications. We study the diffusion of information updates in the whole area, evaluate the impact of energy saving policies in the protocol version run by pedestrian devices, and the impact of contextual awareness about location and motion of nodes in the forwarding policies. The study we present in this paper has been carried out through simulation. To this end we develop a discrete event simulator working on top of mobility and radio propagation traces obtained from the UDelModels tools that allow to obtain realistic traces of mobility and radio propagation.