单向延迟测量的在线实时时钟调整检测算法  

Online Real-time Detecting Clock Adjustment in One-way Delay Measurement

作　　者：王卓[1] 朱德森[1] 汪秉文[1] 

机构地区：[1]华中科技大学控制科学与工程系信息所,湖北武汉430074

出　　处：《小型微型计算机系统》2007年第8期1456-1460,共5页Journal of Chinese Computer Systems

基　　金：高等学校博士学科点专项科研基金项目(20020487023)资助

摘　　要：在网络单向性能指标分析中,使用软件方法对单向延迟时间序列进行分析,在线检测时钟调整位置,消除端系统间的时钟偏差,实现在线时钟同步是提供准确网络单向测量的前提保证.根据端系统间单向时延的结构特征,分析时延在大扰动的情况下,使用滑动窗和自底向上算法进行在线实时时间序列分段来检测时钟调整,存在的分段不准确问题.提出一种基于离线分段和在线检测的时钟调整检测算法,其时间复杂度为O(w),解决了对单向延迟的时间序列进行实时分段准确性低的问题.仿真及实际测试实验表明,该算法是行之有效的.Delay metrics of Internet play an important role in evaluating the network performance. They are also the foundation for other metrics measuring, such as bandwidth, jitter and loss. One-way delay (OWD) measurement has been getting much attention in recent years. A key issue in one-way delay measurement is the removal of relative clock offset and the clock adjustment detection using software algorithm by analyze the delay time series. In this paper, with the time series segmentation technology, piecewise linear algorithms of Bottom-Up and Sliding Window are discussed to be incorrect under the situation of much delay noise. An online real time clock adjustment detecting algorithm by post facto segment and online detect named OCAD is proposed to estimate the clock adjustment, which computational complexity is of order O(w). Experiments show that these algorithms can provide reasonable clock adjustment detection.

关 键 词：单向时延 时间序列 时钟偏差 

分 类 号：TP393.4[自动化与计算机技术—计算机应用技术]