TTDD: Two-tier Data Dissemination in Large-scale Sensor Networks

Sink mobility brings new challenges to large-scale sensor networking. It suggests that information about each mobile sink’s location be continuously propagated through the sensor field to keep all sensor nodes updated with the direction for forwarding data reports. Unfortunately frequent location updates from multiple sinks can lead to both excessive drain of sensors’ limited battery power supply and increased collisions in wireless transmissions. In this paper we describe TTDD, a Two-Tier Data Dissemination approach that provides scalable and efficient data delivery to multiple mobile sinks. In TTDD Each data source proactively builds a grid structure which enables mobile sinks to continuously receive data on the move by flooding queries within a local cell only. Exploiting the fact that sensor nodes are stationary and location-aware, TTDD constructs and maintains the grid structures with low overhead. We have evaluated TTDD performance through both analysis and extensive simulation experiments. Our results show that TTDD handles multiple mobile sinks efficiently with performance comparable with that of stationary sinks.