【摘要】 精确的时间和频率信息对于通信系统各种应用非常重要。传统电路交换通过TDM链路帧同步实现精确频率同步,而分组网络的"存储-转发"特性为同步消息引入延时,要实现精确的能够满足传统通信需要的频率和时间同步更加困难。IEEE1588精密时间同步协议(Precision Time Protocol,PTP)是一个原来应用于工业控制、测试测量等领域低成本高精度的同步协议,根据分组通信网络的特点,提出了IEEE1588在通信中的应用框架,采用虚拟和真实网络环境相结合的仿真方法,分析了所提框架的同步性能及各种性能补偿措施的补偿效果。虚拟网络仿真采用OMNeT++工具,给出网络业务特性对精确时间同步的定性和定量影响。真实网络仿真基于校园网环境,采用软件时间戳标记达到50μs的同步精度。更多还原

【Abstract】 Precise time and frequency information is very important for telecom systems.Traditional Circuit-switching relies on frame alignment of TDM link to provide precise frequency.Packet network introduces delay impairments into synchronization message because of its storage-forward mechanism.IEEE 1588(Precision Time Protocol,PTP) protocol provides a low-cost high-accuracy time and frequency synchronization in industrial control,test and measurement.According to the packet network features,this paper gives a telecom application framework of IEEE 1588.Using the combination methods of virtual and real network simulation,this paper also analyzed the synchronous performance and the compensation effects of the impairments.The OMNeT++ discrete event network simulation gave out the qualitative and quantitative impact of network characteristics.The real LAN network simulation gets a result of 50μs time accuracy which meets the requirement of telecom applications.更多还原