An adaptive framework of multiple schemes for event and query distribution in wireless sensor networks

Abstract

Wireless sensor networks are useful for many real-world applications including environmental monitoring, military applications, disaster management, etc. In many cases, interesting events detected by sensors are disseminated to some targeted node(s) for storage whereas queries for specific event types would be directed by a data dessimination protocol aiming to the "right" storage node(s) for definite answers. Nevertheless, the query/event ratio can be changing over time in many practical applications like the tracking of endangered animals in an open safari due to the seasonal trend or other factors. This varying query/event ratio will significantly affect the overall performance of different data dissemination schemes in the underlying sensor networks. In this paper, we consider an adaptive framework that can flexibly switch from one scheme to another based on the results quickly evaluated by our cost models. We implemented several GHT-based schemes including our adaptive GHT (AGHT) for event distribution in the JSim packages, and compared their performance on an example safari application with changing query/event ratios. In our simulation results, the AGHT clearly excelled the other GHT-based schemes with the lowest storage and communication overheads. More importantly, these promising results shed light on many possible directions for future investigation. © 2007 IEEE.