Research Of Platoon's Wireless Channel Access Management

In the research process of automotive VANETs,many related network protocol standards have been born.The WAVE protocol that is most widely used now is the IEEE.The WAVE protocol is tailor-made for such high-speed mobile special network nodes,and the short message further satisfies the communication requirements of the vehicle in a complex and congested traffic environment.However,in the current WAVE protocol research,there is a lack of research on the special form of the team.The team is different from the ordinary vehicles which are made up of several cars in a linear arrangement.The whole team can be seen as a large vehicle node,but it not only involves External communications,including communication among members of the team,how to design special protocol interactions for the team and make the entire team's transmission efficiency and throughput achieve better results is a research hotspot of VANETs.The research content of this thesis will focus on the special form of the vehicle platoon and put forward specific wireless channel access control mechanism.Including the difference from the traditional interaction process,and based on the p head insisted competition algorithm and multi-channel distribution algorithm for hybrid vehicle types.In the team-oriented MAC protocol proposed in this paper,a new retransmission time slot(REI)will be added in the frame period,and the necessary information will be backed up with the front end.When the retransmission time slot arrives,the front end will control the backed-up information.When broadcast on the channel,the team members jump to the control channel for receiving.During the rest of the time,the team members can stay on the service channel to send and receive service data,which will allow the team members to make full use of the traditional frame period.The traffic channel resources in the idle state of the control channel time slot make the service data transmission and reception efficiency greatly improved.Based on the persistence of the p-based head-on competition algorithm to solve the problem of competition between multiple platoons' front and retransmission time slots,this algorithm will prioritize the front end according to the platoon size and set the corresponding AIFS size for it.This makes it possible for the larger platoon to have a higher probability of access to the channel.This will allow more vehicles in the scene toreceive backup information from the front of the vehicle.At the same time,according to the particularity of the security alarm information,members of the platoon can Accepting the security alarm information sent from any front end significantly reduces the delay of information compared to the situation where each vehicle head is responsible for its own members.In a multi-channel allocation algorithm for hybrid vehicle types,the control channel will be used for contention access,and the service channel will have no contention mode.All vehicles in the scenario will compete for a sender channel request message in the control channel,and the platoon's channel application will be the front end of the vehicle.Sending,this will greatly reduce the number of messages in the control channel,the collision probability will be smaller,while the number of channel applications in the platoon,the front of the car to allocate a correspondingly greater probability of access,making the big platoon of this node Channel requirements are prioritized so that channel allocation efficiency in the network is improved.The research content of this thesis is verified by ns3 network simulation platform.In the simulation of throughput,the MAC protocol of the team using this paper has a28% increase compared with the traditional WAVE protocol.In terms of delay,the success time of the security warning replay of the head vehicle is also shortened by nearly 9% compared with the traditional protocol.In addition,under the strategy of using the fleet as a whole for channel applications,the service channel access time for each vehicle is increased by about 206%.These results show that the research content of this paper has obviously improved the performance of the network of existing teams,and it also has certain reference significance for the future research direction of the platoon.