采用跨层协同设计的思路和定向通信机制,对移动 Ad Hoc 网中的按需路由算法进行跨层优化,提出一种新的 Ad Hoc 按需定向路由算法:CAODR。通过定向天线的使用和网络、MAC 与物理三层之间的跨层协同,实现了定向单播和全向广播的发送方式,...采用跨层协同设计的思路和定向通信机制,对移动 Ad Hoc 网中的按需路由算法进行跨层优化,提出一种新的 Ad Hoc 按需定向路由算法:CAODR。通过定向天线的使用和网络、MAC 与物理三层之间的跨层协同,实现了定向单播和全向广播的发送方式,成功减少了隐藏终端造成的分组碰撞和暴露终端造成的不必要等待。数学推导证明了 CAODR 对隐藏/暴露终端问题的改善。性能分析和仿真结果也表明:它在端到端时延、吞吐率、成功率等性能上的表现优于经典的 AODV 路由算法。展开更多
This paper presents the design of hierarchical communication network for traction power supply supervisory control and data acquisition (SCADA) system. Some key points, such as data transmission synchronization, datab...This paper presents the design of hierarchical communication network for traction power supply supervisory control and data acquisition (SCADA) system. Some key points, such as data transmission synchronization, database distribution, data transformation, and the network communication optimization at the supervisory level of the communication network are discussed. At the control level, based on the specificity of communication lines for electrified railway, a structure of two layer ring telecommunication network and the efficient bi directional polling scheme in software design are utilized. Then, an analysis for the scheme under normal and disturbance conditions is given. By means of the scheme, software switching over at a fault point of a channel is realized automatically.展开更多
文摘采用跨层协同设计的思路和定向通信机制,对移动 Ad Hoc 网中的按需路由算法进行跨层优化,提出一种新的 Ad Hoc 按需定向路由算法:CAODR。通过定向天线的使用和网络、MAC 与物理三层之间的跨层协同,实现了定向单播和全向广播的发送方式,成功减少了隐藏终端造成的分组碰撞和暴露终端造成的不必要等待。数学推导证明了 CAODR 对隐藏/暴露终端问题的改善。性能分析和仿真结果也表明:它在端到端时延、吞吐率、成功率等性能上的表现优于经典的 AODV 路由算法。
文摘This paper presents the design of hierarchical communication network for traction power supply supervisory control and data acquisition (SCADA) system. Some key points, such as data transmission synchronization, database distribution, data transformation, and the network communication optimization at the supervisory level of the communication network are discussed. At the control level, based on the specificity of communication lines for electrified railway, a structure of two layer ring telecommunication network and the efficient bi directional polling scheme in software design are utilized. Then, an analysis for the scheme under normal and disturbance conditions is given. By means of the scheme, software switching over at a fault point of a channel is realized automatically.
