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| 面向车载容迟网络的二维时钟同步算法 |
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赵忠华1,2,3, 皇甫伟1, 刘燕4, 孙利民1
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1.中国科学院 软件研究所, 北京 100190;2.信息安全国家重点实验室, 北京 100049;3.中国科学院 研究生院, 北京 100049;4.北京大学 软件与微电子学院, 北京 102600
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| 摘要: |
| 车载容迟网络中车辆节点频繁移动使得任意节点之间在特定时刻往往不存在一条端到端的通信路径,网络具有间歇连通性和节点移动等特点,以及车辆节点自身携带的时钟振荡器也易受到周围环境因素的影响,晶振频率处于不规则波动的状态,导致车载容迟网络直接引进传统网络中已有的成熟时钟同步算法时会产生很大的局限性和困难性.针对上述问题,提出了一种面向车载容迟网络的二维时钟同步算法,该算法包括纵向维度和横向维度的两个同步过程,与单程同步相比,减少了同步的时间误差,提高了同步精度.实验结果表明,车载容迟网络通过二维时钟同步后能够获得较高的同步精度. |
| 关键词: 车载容迟网络 时钟同步 公交车辆 二维 |
| DOI： |
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| 基金项目:国家自然科学基金(61073014);国家重点基础研究发展计划(973)(2011CB302902);国家科技重大专项(2010ZX03006-007) |
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| Two-Dimensional Clock Synchronization Algorithm for Vehicular Delay Tolerant Network |
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ZHAO Zhong-Hua1,2,3, HUANGFU Wei1, LIU Yan4, SUN Li-Min1
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1.Institute of Software, The Chinese Academy of Sciences, Beijing 100190, China;2.State Key Laboratory of Information Security, Beijing 100049, China;3.Graduate University, The Chinese Academy of Sciences, Beijing 100049, China;4.School of Software and Microelectronics, Peking University, Beijing 102600, China
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| Abstract: |
| In vehicular delay tolerant network(VDTN),vehicles nodes often move frequently,which results in existing no end-to-end communication path between any nodes at a given moment,and VDTN has intermittently connectivity.The clock oscillators in the vehicle nodes are also susceptible to environment factors,and the crystal frequency fluctuates in the state of irregular.There exits much limitation and difficulty,when the traditional network clock synchronization algorithms are introduced directly into VDTN.A two-dimensional clock synchronization algorithm for vehicular delay tolerant network is proposed,which includes two synchronization processes in the vertical dimension and in the horizontal dimension.The two-dimensional clock synchronization algorithm reduces the time synchronization error and improves the synchronization accuracy,compared with the one-way synchronization.The experimental results show that VDTN obtains a higher synchronization accuracy through the two-dimensional clock synchronization algorithm. |
| Key words: vehicular delay tolerant network clock synchronization bus vehicle two dimensions |
