The PicoRadio Project at the Berkeley Wireless Research Center (BWRC) is focusing on networks of extremely small self-powered nodes communicating via radio. A PicoRadio network must be self-configuring, power-aware, and scalable, so the media access and network protocols are necessarily complex. The goal of the project is to build a single-chip version of a node in which much of the protocol implementation is to be hard-coded on the IC.
In order to ensure that the protocols work before the chip is built, we have implemented the protocol suite on the PicoRadio test bed: a network of nodes built from off-the-shelf components with configurable elements such as a processor and programmable logic. The test bed emulates fairly closely the conditions expected when the single-chip nodes are deployed, so we can gain a detailed understanding of the functionality of the protocols, the behavior of the network under dynamic conditions, and the parts of the protocol suite that should be parameterized.
The test bed implementation has already proven to be a valuable tool for understanding network behavior. The implementation team has performed a large set of measurements under varying conditions, and is continuing to gather data. Lessons learned from previous studies have been incorporated into the protocol set, for instance, the stability of the media access protocol in the presence of rapidly changing radio channels has been greatly improved. These lessons are currently being applied to the implementation of a preliminary version of the final PicoRadio node.
4Visiting Researcher, Swiss Federal Institute of Technology, Lausanne