在ZigBee无线网络中,为实现中继节点的休眠和唤醒功能,并达到降低系统功耗的目的,提出了一种新的时间同步算法。该算法利用模拟开关和RTC模块的中断信号控制主控模块的供电,使路由设备进入超低功耗运行状态;同时采用IEEE1588的精确时钟同步协议PrrP完成MAC层的时钟同步,减少了同步算法协议层间损耗,解决了传统时间同步算法精度不高的问题。试验表明,改进后同步算法的同步精度达到+50μs,系统运行功耗极低;节点仅靠锂电池即可持续工作半年以上,能够满足低频率数据监控等应用,使无线网络应用更加灵活、广泛。
In order to realize the sleep and wake-up functions of the relay nodes in ZigBee wireless network, and to reduce the system power consumption, a new time synchronization algorithm is proposed. It uses interrupt signals of analog switch and RTC module to control the power supply for main control module, and to make routing equipment get into ultra-low power consumption operation state. Meanwhile, IEEE 1588 precision time protocol (PTP) is used to complete the clock synchronization of MAC layer, reduce the loss between layers of synchronization algorithms protocol, and solve the problem of low accuracy of traditional time synchronization algorithm. Tests show that synchronization accuracy of the improved synchronous algorithm reaches + 50 μS, and the system operation power consumption is extremely low. Relying on Lithium battery, the nodes can continuously work up to six months. The method also can monitor the low frequency data, and make the application of wireless network more flexible and wider.