Time synchronization method based on vehicle ad hoc network topology structure

A network topology and time synchronization technology, applied in network topology, synchronization devices, electrical components, etc., can solve problems such as node overload and overall performance degradation

Inactive Publication Date: 2009-09-16
UNIV OF SCI & TECH BEIJING
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Problems solved by technology

Although nodes with GPS devices are helpful for vehicle synchronization, from a practical point of view, as a time server, energy and bandwidth need to be paid. From the concept of a distributed network, some nodes should not be overloaded, because In a network with roughly the same processor power, a singularity may break the balance of the network, resulting in a decrease in overall performance

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  • Time synchronization method based on vehicle ad hoc network topology structure
  • Time synchronization method based on vehicle ad hoc network topology structure
  • Time synchronization method based on vehicle ad hoc network topology structure

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Embodiment Construction

[0055] like figure 1 As shown in , in a real complex intersection, the nodes identified in the intuitive analysis diagram are the best secondary servers. According to the algorithm of the present invention, the same effect can be achieved, refer to figure 2 , 3 , 4, the specific implementation is as follows:

[0056] 1. Server A broadcasts its time and neighbor list information in its route to its signal coverage area (assumed to be a standard circle) when the speed is lower than a certain speed, and initiates synchronization. A low-speed node is likely to be at a certain traffic intersection and can directly synchronize more nodes. With this multicast method, although the message is long, the efficiency is high, and all neighbor nodes can receive the message.

[0057] 2. Each node that receives the message performs a set subtraction operation, that is, subtracts the received list from the local neighbor list, so as to obtain the nodes that node A can reach through this n...

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Abstract

The invention discloses a time synchronization method based on the vehicle ad hoc network topology structure. According to the feature that the overall distribution of the vehicles is characterized by I type, T type or X type, the vehicle with GPS facility is used as an initial time server; according to the concept of grading, the number of the neighbor nodes in the routing table is taken as the standard, synchronization is carried out while the optical sub-grade time server is selected, wherein the selected lower-grade time server is in accordance with the characteristic shape of the road and satisfies the requirement of having a plurality of unsynchronized lower-grade neighbor nodes. The invention is characterized in that: the synchronization and the selection of the optical sub-grade server are carried out at the same time, thus preventing the selected sub-grade server from failing caused by fast changing routing; multicast and shorter synchronizing information are adopted for time hack, thus reducing the occurrence of the conflicting and paralyzing of the network when the network performs global synchronization; the server only performs the insertion sort process once and other operation is totally shared by other nodes, thus reducing the operand of the server.

Description

technical field [0001] A time synchronization method based on vehicle ad hoc (self-organizing) network topology belongs to the research field of mobile ad hoc network time synchronization. technical background [0002] The ad hoc network is a distributed network without infrastructure. This type of network consists of wireless mobile nodes that form an autonomous system. Each node is both a host and a router. There is no centralized network management, and it can flexibly adapt to the topological structure. Variety. The processors of each node have a high degree of autonomy and cooperate with each other, and sometimes even need to share all the software and hardware resources in the system. Time is an important coordinate in a distributed network and an indispensable parameter. Usually, there is a deviation between any clock and the standard time, and the rate of each clock is different. Therefore, people need to regularly synchronize the time of each node of the network t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04W56/00H04W84/18
Inventor 杨扬侯国梁周贤伟安建伟杨裕亮
Owner UNIV OF SCI & TECH BEIJING
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