Research On WAVE Protocol For Internet Of Vehicle Based On Cognitive Radio

In recent years,with the continuous progress of science and technology related to intelligent cities and the Internet of Things,the research of road traffic network,as the basis of social development,has also received widespread attention.In this context,researchers around the world are increasing their research on internet of vehicle year by year,and the research on internet of vehicle communication protocols is becoming more and more perfect.Internet of vehicle refers to the network that completes information exchange between vehicles and people,vehicles and vehicles,vehicles and roadside units under the norms of certain communication protocols,and the communication protocol is the rules that all parties in the vehicle networking must abide by to complete information exchange.At present,WAVE(Wireless Access in Vehicular Environment)protocol developed by IEEE organization is the most important vehicle networking communication protocol for research and application worldwide.This protocol is composed of 802.11 p and 1609 protocol family.Its main function is to formulate internet of vehicle communication rules and achieve the goal of information transmission in high-speed environment of internet of vehicle.In this paper,aiming at the low efficiency of information transmission and spectrum utilization of WAVE protocol,cognitive radio technology is introduced to study the cognitive vehicle network MAC protocol combined with priority and slot allocation,the cognitive vehicle network MAC protocol based on spread spectrum and the cognitive vehicle network spectrum sensing method based on double threshold energy detection.Firstly,in order to solve the problem of unclear priority division of user information and low efficiency of security information transmission caused by fixed slot allocation in WAVE MAC protocol,this paper proposes a new MAC protocol based on cognitive radio technology(CR-WAVE MAC).The protocol first uses enhanced distributed channel access(EDCA)parameter adjustment strategy,introduces service type and number of users as EDCA parameter adjustment standard,divides user information priority,and then uses cognitive radio spectrum sensing and allocation technology to allocate dynamic slots according to information priority level,so as to increase the transmission efficiency of security information.The simulation results show that the proposed CR-WAVE MAC protocol significantly improves the transmission rate and throughput of road safety information and reduces the transmission delay.Secondly,in order to increase the transmission opportunities of security information,this paper proposes a cognitive vehicle networking MAC protocol based on band switching.The protocol uses cognitive radio technology to evaluate the channel status of DSRC authorized band and ISM and UNII-3 unauthorized band.The dynamic channel allocation mechanism can switch the unsafe data information of vehicular network to channel transmission in ISM or UNII-3 band when the authorized band is full.It improves the access priority of transmission media of secure data,and thus improves the transmission quality of secure information.The simulation results show that the SS-WAVE MAC protocol proposed in this paper improves the transmission efficiency of road safety information by spreading spectrum.Finally,in order to improve the spectrum utilization of WAVE protocol in vehicle networking,this paper studies the spectrum sensing method based on double threshold energy detection in the internet of vehicles environment.Based on the single-threshold energy detection method,this method introduces the number of vehicle nodes in the network coverage,and carries out dual-threshold energy detection in the local decision stage.At the same time,the method also sets a double threshold "no decision" area to prevent users from uploading local decision results which are disturbed by noise to affect the success rate of spectrum sensing,thereby improving the spectrum utilization.The simulation results show that the proposed spectrum sensing method can effectively improve the spectrum detection probability under different vehicle densities and signal-to-noise ratios.