SensorBus - A Policy-Based Middleware for Wireless Sensor Networks

The use of middleware to develop distributed applications liberates the programmer of the concerns (communication and coordination among software components) imposed by the distributed network environment. Besides these concerns, in wireless sensor networks are considered, also, their specific characteristics (address, mobility, amount and limited resources of the sensor nodes). This paper describes the implementation and performance evaluation of SensorBus, a message-oriented adaptive middleware for wireless sensor networks that uses policies to assist to the several characteristics of the wireless sensor networks. Policies are implemented in an application profile, through metadata, encoded in XML documents. Performance evaluation of SensorBus is made through their two main services: application and context. We used measurement techniques and simulation to carry out the experiments. Experiments show that using metadata to incorporate policies in the middleware does not imply undue overheads.