Hello message exchange method for greedy geographical routing protocol

Abstract

The invention discloses a hello message exchange method for a greedy geographical routing protocol. The realization scheme of the method is that the road width is considered to be far smaller than communication radiuses of vehicles; the vehicles on a road are approximately taken as a one-dimensional network; the communication ranges of nodes are discretized; mathematical modeling is carried out on link states by employing a Markov process; links are described as Markov links with absorption boundaries; link connection probabilities are calculated according to a first arrival probability and a one-step transfer probability matrix; corresponding relationships can be established between the link communication probabilities and beacon exchange periods according to statistic properties; the width of a link disconnection interval in the minimum hello message exchange period of the vehicles can be designed; and neighbor nodes in the link disconnection interval will be deleted by forwarding nodes. Compared with the greedy geographical routing protocol, the method has the advantages that the data packet delivery success rate is improved, the relatively low control overhead is obtained, and the method can be applied to a vehicular ad-hoc network.

Description

technical field [0001] The invention belongs to the technical field of communication, and mainly relates to a hello message exchange method of a greedy geographic routing protocol in a vehicle ad hoc network. Background technique [0002] In the VANET, the greedy geographical routing protocol calculates the distance to the target node based on the location information of the surrounding one-hop neighbor nodes and performs greedy forwarding. Each node needs to establish and maintain the neighbor node table through the Hello message exchange, so as to obtain the local topology status information. However, most greedy geographic routing protocols use periodic Hello message exchange, that is, each node broadcasts a Hello message with a lifetime of 1 hop to all neighbor nodes to inform itself of its existence and location information. To build and maintain their own neighbor node table. In the traffic environment, due to the roads in the VANET restricting the trajectory of vehi...

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Problems solved by technology

In the traffic environment, due to the roads in the VANET restricting the trajectory of vehicles, the existence of roadside obstacles, non-uniform vehicle distribution and high-speed movement of vehicles, there is poor link stability, and it is easy to In the periodic Hello message exchange algorithm, the location information of the neighbor nodes maintained by the node cannot accurately reflect the change of the node location, nor can it reflect the on-off of the link in time, so that the best next The jump node will become a non-optimal candidate node, and the robustness and immediacy of data transmission will be seriously disturbed

[0003] The existing Hello message exchange algorithm is implemented in the Ad hoc network. The VANET is a highly dynamic network. There is a speed difference between vehicles. The width of the lane is relatively small compared to the communication radius of the vehicle. The vehicles can be considered to exist in a In the three-dimensional space, the connectivity analysis of the Ad Hoc network cannot be directly introduced into the VANET; on the other hand, most of the hello message exchange cycles formulated by these algorithms are obtained qualitatively, lacking the knowledge of the network dynamic characteristics and link characteristics. theoretical analysis

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