A clock synchronization method and device

Abstract

Embodiments of the invention disclose a clock synchronization method and device. The method and the device are applied to a network fusing radio over fiber RoF and a passive optical network PON. The method comprises the following steps that a hybrid optical line terminal OLT sends an obtained analog atomic clock synchronization signal to a network module through an RoF link, and the network module extracts the analog atomic clock synchronization signal; and the network module computes clock adjustment information and adjusts a clock of the network module through moment information recorded by the network module. According to the method and the device, in the RoF technology-based clock synchronization method, the RoF link is utilized for transmitting a precise analog atomic clock synchronization signal obtained by the hybrid OLT and the network module extracts the analog atomic clock synchronization signal, so that a problem of distortion after digitization of the clock synchronization signal can be effectively avoided, the clock synchronization precision of the network module at the access side is improved and the precise network clock synchronization is realized.

Description

technical field [0001] The invention relates to the technical field of network communication, in particular to a clock synchronization method and device for a network based on the integration of wireless over light and passive optical networks. Background technique [0002] In the process of network communication, in order to ensure the quality of communication and make the business run normally, precise network clock synchronization must be required, that is, the time or frequency between network devices must be kept within a reasonable error level. Network clock synchronization includes time synchronization and frequency synchronization. Especially in the wireless access system, each base station node is required to strictly maintain the synchronization accuracy of the wireless interface, which requires each base station node to extract the clock through GPS to ensure its synchronization. However, the GPS clock synchronization solution requires the antenna to have a good ...

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Problems solved by technology

However, the GPS clock synchronization scheme requires the antenna to have a good view of the sky in order to ensure that the receiver can receive effective signals, which increases the difficulty of GPS site selection, and the feeder line needs to be erected between the antenna and the base station, which increases the erection cost

In addition, the base station has no other backup clocks, and the system reliability is low

Although the IEEE 1588V2 clock synchronization protocol can solve the problems of high time synchronization cost and insufficient precision, and its synchronization accuracy can reach sub-microsecond level, what is transmitted based on this protocol is a digital clock signal, that is, in the clock synchronization process, first To digitize the clock signal, this process will inevitably cause the loss of many attributes in the clock signal, resulting in the distortion of the clock signal recognized by the network module at the receiving end, which will have a certain impact on the synchronization delay and accuracy, and ultimately affect the communication quality.

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