【作者】 张继荣；

【导师】 吴守贤； 方强；

【作者基本信息】 中国科学院研究生院（国家授时中心） ， 天体测量与天体力学， 2008， 博士

【摘要】 提高通信网络运营质量和运营效率,发展一些新的通信业务,以及运营商之间的网间结算,都需要统一的时间。为了解决电信网自身对时间同步的需要,同时寻求一种可与全球定位系统(GPS)授时精度相当的授时新方法,满足其他行业统一时间的需要,本论文开展基于SDH网络的时间传递方法研究。利用SDH网络组建全国的时间同步网,需要研究SDH网络传递路径的时延和时延误差。论文采用理论分析、工程测量和仿真研究相结合的方法,提出了一种适合SDH网络结构特点的时间传递方法——环回采样法,该方法很好地解决了SDH环形网络双向信号传递路径不对称问题,大大提高了时间传送的精度。该方法适用范围广,可以在任意结构的SDH网络和网元中使用。论文对SDH单节点网元的处理时延进行了仿真,并与工程测量结果进行了对比,获得了一致的结果。论文基于提出的环回采样法,对SDH单节点网元发送部分和接收部分的不对称处理时延进行了理论分析和仿真测量。在此基础上,对8000公里长,经过81个SDH网元传递的时间精度做出了预测,获得了1纳秒以内的精度。论文还设计了实现环回采样时间传递的具体方案,设计了需要增加的硬件电路和软件流程。论文设计的时间同步网,综合考虑了已有的SDH频率同步网,将频率同步网和时间同步网统一在一起,较好的解决了各种通信网的时间同步,同时还可以为其他行业提供所需的时间同步信号。更多还原

【Abstract】 Unified time is need when improving the quality of telecommunication network operation, developing new telecommunication business, and doing net accounts between operators. In order to satisfy the need of telecommunications networks to synchronize time while searching for a new time service method with the accuracy equal to the one of GPS to meet the requirement for time unification of other industries at the same time, this article develops a research on time delivery research based on the SDH network.To build nationwide synchronized time net using SDH network, we must study the time delay in SDH network transmission path. In a way of combing theory analysis, engineering measurement, and simulated research, this article offers a method for time transmission suitable for the characteristics of SDH network structure—loop-back and sampling method, which effectively solves the problem of the asymmetric two-way signal transmission path of the SDH ring-network and, to a great extent, enhances the accuracy of time transmission. This method also has a wide scope of application and can be used in SDH network as well as network element with any structure.This article simulates the time-delay in the single-node SDH network element processing, and gains the same result with the one of engineer measurement after comparison.With the stated loop-back and sampling method, this article makes theory analysis and simulated measurement on the asymmetric processing time-delay in the transmitting and receiving part of the single-node SDH network element. Based on this, the time accuracy transmitted through 81 SDH network elements at the length of 8000 kilometers is calculated; the accuracy within one nanosecond is gained In this article, a specific plan to realize loop-back and sampling time transmission with hardware circuit and software process needing to be added is designed. The time synchronizing network designed in this article and the existing SDH frequency synchronizing network are unified, which effectively solves the problem of time synchronization in all kinds of telecommunication network, and is capable of providing time synchronizing signals for other industries.更多还原