Synchronous communication requires both parties to communicate at the same clock frequency and coordinate accurately, ensuring accurate synchronization of the sender and receiver by sharing a single clock or timing pulse source.
Clock synchronization is an important foundation for synchronizing wireless communication networks. It is one of the core technologies for correct reception of wireless signals, time division multiple access, power control, synchronous frequency hopping and other functions. Each node in the wireless communication network has an independent hardware clock. The hardware clock is timed by a crystal oscillator and a counter. Due to manufacturing processes, external environment, hardware aging, etc., the frequency of the crystal oscillator of the hardware clock of each node is different. , so completing frequency synchronization between node clocks is an important guarantee for time synchronization between network nodes. [0004] One type of existing technology relies on external clock sources to complete time synchronization between wireless communication network nodes. For example, satellite timing systems such as GPS and Beidou are used to synchronize the time of the wireless communication network, and corresponding time stamp signal receiving devices are integrated in the nodes. Each node in the wireless communication network is independently synchronized with the time of the satellite timing system to complete the entire system. Network time synchronization.
[0005] Using IEEE1588 (Network Measurement and Control System Precision Clock Synchronization Protocol) timing to synchronize the time of the wireless communication network requires a stable clock source external to the network to complete the time synchronization of the wireless communication network step by step. [0006] The time synchronization scheme of wireless communication networks using satellite timing systems such as GPS and Beidou requires integrating time stamp signal receiving equipment in network nodes, which increases the cost of network nodes, and when the satellite timing signal is interfered or the signal strength is relatively high, In weak scenarios, network synchronization accuracy cannot be guaranteed. [0007] Utilizing IEEE1588 (Network Measurement and Control System Precision Clock Synchronization Protocol) timing to carry out a time synchronization scheme for a wireless communication network requires an external stable clock source, which increases the cost and implementation difficulty of the wireless communication network. At the same time, this scheme requires a stable and reliable clock. Only the transmission network can ensure the stability of time synchronization, which is difficult to achieve for wireless communication networks. [0008] The other type is to complete time synchronization step by step by establishing a hierarchical relationship between nodes in the wireless communication network. This time synchronization scheme selects a clock to track the source node, and the current node only performs time synchronization with the selected tracking source node. [0009] When the frequency deviation between nodes in the wireless communication network is large, the low-order modulation between nodes cannot communicate normally. At this time, the nodes cannot receive the time synchronization information of the clock tracking node, so the wireless communication network time cannot be guaranteed. The synchronization was successfully completed. And the frequency difference between nodes will lead to differences in clock timing speed, affecting time synchronization accuracy.