Design and Deployment of Wireless Networked Embedded Systems

The recent rise and widespread adoption of wireless networking technologies for mobile communication applications has sparked numerous visions of an ever more networked and interactive world. One such vision proposed in the late nineties are Wireless Sensor Networks (WSN), where wireless communication and computing elements are combined with integrated sensors to enable tightly coupled interaction with the physical world. As a new application domain for wireless technology, key challenges here are (i) the limited resources of the highly integrated nodes that are to be leveraged by the amount of devices deployed and the collaboration between them, (ii) the tight coupling of application, nodes and the environment and (iii) the broad usage profile by systems-experts and non-expert users alike. First medium-scale experiments and field-trials have reported that it is increasingly hard to design, develop, deploy, test and validate systems consisting of more than a hand-full of nodes, especially when situated in a real-world environment. Prototypical applications are scarce, seldom consisting of more than a few tens to a hundred nodes. Setting up large, heterogeneous, interactive and functional systems as forecast in the visions is no small task; currently more an art than a systematic engineering effort. Coordinated methods and tools for the design and deployment of wireless networked embedded systems are missing today. With this work, we contribute to the design and development of wireless networked embedded systems. The specific contributions are presented and discussed in the context of a vertical slice of the design space concerned and the relevant questions encountered: (i) Functional and qualitative requirements of a location management service for WSNs based on measurements and simulation have been developed. We present one of the earliest algorithms for the distributed computation of node location. (ii) A novel platform for fast-prototyping of WSNs has been developed. This platform has successfully served numerous researchers, among ourselves, as an underlying infrastructure for experimentation and education. (iii) The BTnode platform has been used to develop multihop networks and topology control mechanisms for Bluetooth scatternets. To our knowledge, the experiments presented are the largest connected Bluetooth scatternets reported of to date. (iv) The concept of a deployment-support network as a powerful tool for the development, deployment, test and validation of WSNs is presented in conjunction with experimental evidence on the feasibility of the approach.