B-Geocasting: Effective data dissemination protocol to support group mobility of sinks

This paper studies on data dissemination for mobile sink groups in wireless sensor networks. A mobile sink group denotes a set of tightly coupled mobile sinks for team collaborations such as a team of firefighters and a group of soldiers. This mobile sink group has a collective movement feature. That is, even though sinks in a group randomly move in their own personal spaces, they collectively move together as a single entity. For mobile sink groups, previous studies provide flooding-based protocols that determine immediate areas of a group at moments, which are successive snapshots of a group continuously moving, and then propagate data within the areas by flooding. However, since a group is still moving during decision of each snapshot, they cause asynchrony between an immediate area and the actual area at a moment. Eventually, it harms reachability and energy-efficiency. This paper therefore proposes a novel data dissemination protocol that takes into account continuous motion properties of a mobile sink group: slowly varying and streamlike movement. Based on the slowly varying property, the protocol predictively and effectively deliver data to a mobile sink group through a band of sensor nodes located in front of the streamlike trajectory of the group. Numerical analysis and computational simulations prove that this band-based data dissemination show better performances than the previous schemes with respect to both reachability and communication costs including data forwarding as well as signaling in a variety of scenarios.