Coverage Problems in Wireless Sensor and RFID Systems

The rapid self-configuration, ease of deployment and§small cost of components motivate the popularity of§wireless sensor networks, the recent interest§generated by wireless Radio Frequency Identifier§(RFID) systems and their envisioned integration.§While the autonomous operation and random deployment§of components determine the low set up cost of such§systems, they also become sources of problems. This§thesis studies the problem of extending the network§lifetime of sensor and RFID systems by defining and§detecting redundant components whose simultaneous§deactivation maintains the initial network coverage.§§First, we present efficient distributed algorithms§for computing and maintaining solutions for the§redundant sensor elimination problem. Second, we§study three problems in dense RFID deployments, the§reader collision avoidance problem, the optimal tag§reporting problem and the optimal tag coverage§problem. We propose a distributed and localized§Redundant Reader Elimination (RRE) algorithm that§addresses these problems. We rigorously analyze the§performance and accuracy of all our contributions and§provide results from elaborate simulations for a wide§range of system parameters.