Integrating Wireless Sensors and RFID Tags into Energy-Efficient and Dynamic Context Networks

Context-aware systems have traditionally used distributed sensors to gather context information. The unique identity provided by radio frequency identification (RFID) tags could provide additional information to the sensor data. However, the task of matching identity and sensor information in the same context is not trivial. By placing wireless sensor nodes in the same RFID tagged objects, we can build distributed wireless networks that collaborate to produce uniquely identified context. In this paper, we introduce a set of network protocols that dictate the formation of context-specific wireless sensor networks (WSNs). One of the main goals of our protocols is to maintain an energy-efficient WSN, in which network members can join and leave the network in a dynamic, transparent way. Simulations show that our design provides important improvements in network lifetime and that it is specially suited for dynamic environments. Additionally, we describe our implementation experience and provide a set of tools for creating and evaluating our application.