Node/Proxy portability: Designing for the two lives of your next WSAN middleware

Middleware for wireless sensor and actuator networks (WSANs) provides powerful programming abstractions which simplify application development. While it is highly desirable to reuse WSAN middleware across a wide range of hardware platforms, in practice, complex middleware may not fit in nodes with limited resources. As one possible solution, we propose the so-called proxy approach: the middleware is ported on a general purpose computer, from where the sensors and actuators of the resource-constrained nodes are accessed remotely yet in a way that is transparent to the application, which runs unmodified, as if it resided on the physical nodes. We provide design guidelines and a middleware transformation process for implementing the proxy approach in a structured way. We also present a concrete implementation of the proxy approach for our own middleware, along with a performance evaluation of the proxy software environment in a wired testbed with almost 200 sensor nodes.