Performance Evaluation of a Synchronization Protocol for Rechargeable Sensor Networks

Rechargeable sensor networks have been studied as candidates for next-generation wireless sensor networks. However, rechargeable sensor nodes cannot always communicate with other nodes, because they typically do not receive a stable supply of power. To cope with this problem, we propose a dynamic synchronization protocol that allows the synchronization of transmission and reception in rechargeable sensor networks. The protocol has three phases of synchronization. In the first phase, the charge rate is sent to the sink by piggybacking onto the sensor data. In the second phase, the minimum charge rate is propagated from the sink node. All nodes receiving the minimum charge rate can calculate the length of the transmission cycle. In the third phase, each node rearranges its own cycle length by inserting the sleep time and synchronizes the transmission time by changing the sleep time. The sleep time is changed according to the sensor data reception from the backward nodes. The simulation results confirmed the effectiveness of the proposed method.