A middleware for task allocation in wireless sensor networks

Resource constrained platforms, dynamic nature, and complex applications set challenges to the development of wireless sensor networks (WSN). Sophisticated tasking and networking control is required in WSNs to reach lifetimes in order of years. This paper presents a WSN node middleware, which controls task allocation and WSN topology according to the current requirements of the application. The middleware uses a lightweight algorithm that balances communication and computation load between nodes. The discovering of resources and application tasks are comprised by a tuple space that selectively disperses information to nodes. The middleware has been implemented and evaluated in a wireless sensor network simulator (WISENES) that models resource usage and network operation accurately. The results show that in a static network configuration the obtained lifetime with our middleware is 6.8 times longer compared to an uncontrolled network while the increase in processing is negligible and the peek data memory usage increases by 11.6%. In a dynamically changing network the lifetime increases by a factor 3.9. Our middleware does not limit the applications and networks and improves the performance and predictability of WSNs significantly