Collaborative Data Delivery in Energy-Synchronized Sensor Networks

In an energy-synchronized sensor network, each sensor node needs to synchronize its duty-cycle with its residual energy (or energy harvesting rate) to meet a predefined network lifetime requirement. A key research challenge of such energysynchronized sensor networks is how to collaboratively utilize the heterogeneous node duty-cycles for efficient and fair data delivery. In the proposed system, a collaborative data delivery protocol is designed to exploit multiple energy-synchronized paths based on a new max-flow min-variance algorithm. In consort with this data delivery protocol, a localized TDMA MAC protocol is designed to synchronize nodes’ duty-cycles and mitigate media access contentions. The time synchronization is realized through a low-cost and low-power WWVB receiver. We have conducted extensive simulations and experiments to evaluate the system. The results demonstrate that this design not only increases network throughput and fairness, but also increases network lifetime, comparing to the existing protocol stack in TinyOS for duty-cycled sensor network.