摘要
We consider the goal of adaptively controlling access to medium in wireless sensor networks with minimal footprint and complexity. Lightweight protocols are desirable in general and inevitable in some real-world applications such as infant monitoring. We assume high-data-rate, resource-constrained wireless sensor nodes in a star network. We take a deterministic approach to contention resolution to achieve bounded latency on data transmissions while reducing the overhead. In addition to simplicity and small footprint, our approach requires fewer message exchanges compared to the state of the art. We then present a lightweight hybrid protocol that is seamlessly integrated with the proposed contention-resolution scheme, one better suited for delay-sensitive applications with real-time constraints by providing determinism. Another feature of the proposed protocol is that it requires carrier-sensing hardware only on the base station but not on the sensor nodes. The average probing complexity of our protocol in a highly dynamic network is O( n/log n) per round, and experimental results show the proposed scheme to be scalable and highly adaptive to the contention level.