Backoff method based on probability forecasting

Abstract

The invention discloses a backoff method based on probability forecasting. According to the method, by establishing a Markov chain model, the relations of the changes of collison probability and expiring probability of a beacon message along with the minimum contention window are deduced theoretically, and it is guaranteed that the acceptance rate of a broadcast message achieves the optimum; with regard to the problems that backoff factors of a traditional vehicle-mounted self-organizing network backoff method are too simplex, and backoff order number magnitude is overlarge, the backoff method based on probability forecasting (CEB for short) is provided. The method is put forward on the basis of the idea of the relations among beacon message collision probability, the expiring probability and the competition window values, and the competition window values are adjusted according to the relative magnitude and linearity according to the collision probability and the expiring probability. Through the method, the acceptance rate of the broadcast message and performance in the average arrival time delay are improved, the fairness of channel access is optimized, and the priority of an access channel of the emergent broadcast message can be guaranteed.

Description

technical field [0001] The invention relates to a backoff method based on probability prediction in a vehicle self-organizing network, and belongs to the technical field of network communication. Background technique [0002] At present, vehicular ad hoc network has gradually become a new way to solve various traffic problems, and has been vigorously developed in recent years. Among them, safety applications are its basic applications, which are mainly used to solve traffic accidents and provide traffic warnings. Security applications have extremely high requirements on the reception rate and average arrival delay of broadcast messages, but due to the limitations of the traditional Binary Exponentially Backoff (BEB) method in the vehicular ad hoc network IEEE802.11p protocol, its performance cannot meet the security requirements. application requirements. [0003] In 1990, the IEEE802 Standardization Committee established the IEEE802.11 Wireless LAN Standard Working Group. ...

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to provide a back-off method applied to the media access process of a vehicle-mounted ad hoc network. The method aims at the problem of low reception rate of broadcast messages in traditional methods. By establishing a Markov chain model, the method derives the beacon message theoretically. The relationship between the collision probability and the expiration probability and the change of the minimum competition window ensures that the reception rate of broadcast messages reaches the best; in view of the problems that the traditional vehicular ad hoc network backoff method has too single backoff factor and too large backoff order range, the present invention provides a A backoff method based on probability prediction (CEB for short), which is proposed based on the idea of ​​the relationship between beacon message collision probability, expiration probability and contention window value, linearly adjusts the contention window value according to the relative size of collision probability and expiration probability

Images