Programming Wireless Sensor Networks: Fundamental Concepts and State of the Art

Wireless sensor networks (WSNs) are composed of tiny devices equipped with computation, communication, and sensing/actuating capabilities. These networks recently attracted great interest in a number of application domains concerned with monitoring and control of physical phenomena, as they enable dense and untethered deployments at low cost and with unprecedented flexibility. However, application development is still the main hurdle to a wide adoption of WSN technology. Programming is typically carried out very close to the operating system, therefore requiring the programmer to focus on low-level system issues. This not only shifts the focus of the programmer away from the application logic, but also requires a technical background that is rarely found among application domain experts. The need for appropriate high-level programming abstractions, capable to simplify the programming chore without sacrificing efficiency, has been long recognized and several solutions have been hitherto proposed, which differ along many dimensions. In this paper, we survey the state-of-the-art in programming approaches for WSNs. We begin with a characterization of WSN applications, to identify the fundamental requirements programming platforms must deal with. Then, we introduce a taxonomy of WSN programming abstractions which captures the fundamental differences among existing approaches, and constitutes the core contribution of this paper. Our presentation style relies on concrete examples and code snippets taken from programming platforms representative of the taxonomy dimensions being discussed. We use the taxonomy to provide an exhaustive classification of existing approaches. Moreover, we also map existing approaches back to the application requirements, therefore providing not only a complete view of the state-of-the-art, but also useful insights for selecting the programming abstraction most appropriate to the application at hand.