Performance Test Method Based On C-V2X High-density Communication Scenario

In recent years,with the gradual commercialization of driver assistance functions such as cruise control,intelligent parking assist,and collision warning,the apply of ICV（Intelligent Connected Vehicle）is gradually popularized.The IOV（Internet of Vehicles）,as an important realization path for making vehicles intelligent and connected,is also developing rapidly.V2X（vehicle to everything）is a new communication technology that connects vehicles with everything.Compared with the traditional intelligent driving based on visual perception systems such as cameras and radars,V2 X technology greatly reduces the cost and is an important development direction for future intelligent driving.In recent years,C-V2 X,as the main direction of our country’s V2 X development,has gradually become the mainstream technology of V2 X development in the world.At present,C-V2 X has not yet achieved large-scale commercial use,and most of the related test activities are in the exploratory stage,and no authoritative and complete test specifications have been formed.For the existing tests,most of the tests are limited by the experimental conditions,experimental sites,and experimental equipment,and have not been able to obtain very representative test results.At the same time,there is a lack of research on the ability to cope with the high-density communication scenarios faced by the large-scale commercialization of C-V2 X in the future.Based on this,this paper studies the performance test based on C-V2 X in high-density communication environment from multiple aspects,and gives a complete set of test methods,and more than 50 teams composed of more than 100 companies in the industry chain,that is,more than 50 test equipment,have used this test method to carry out field tests for nearly a month.In this paper,the test scene is set as the intersection in the closed test field,and two scenarios of driving in the same direction and driving in the opposite direction are set.For the driving in the opposite direction,we also divide it into two scenarios: driving closer and driving farther.In the performance evaluation of C-V2 X equipment,PER（packet error rate）,IPG（Inter Packet Gap）and ITT（Inter-Transmit Time）are important indicators to measure the communication performance of the device.In the performance evaluation of C-V2 X equipment,the PER and the IPG are important indicators to measure the performance of the equipment,which measures the reliability of C-V2 X communication and ensures the continuous and stable operation of C-V2 X applications.We give the analysis methods for these indicators and analyze their performance on the test results;In particular,for the PER indicator,the causes of packet errors are mainly divided into two parts: the sending device fails to send packets and the receiving device fails to receive packets.Since it is difficult to obtain the actual packet sending situation of the bottom layer of the sender,the current research is basically the analysis of the end-to-end PER.In this regard,this paper also provides an analysis method for the packet loss phenomenon at the sender end in C-V2 X communication.The analysis of the PER is divided into two parts,which are the PER at the sender end and the PER at the receiver end.Based on this method,the data from the above tests were analyzed;In C-V2 X applications such as forward collision warning,the perception and prediction of the surrounding vehicles’ trajectories are crucial.Based on this,this paper proposes a vehicle trajectory prediction method based on BSM,and uses the data obtained from the above tests to verify it.Through the above test and analysis,we concluded that: At present,various types of C-V2 X communication equipment can basically meet the communication needs in a high-density communication environment;For the PER analysis,although the phenomenon of packet loss at the sending end is often ignored,it is an important part of it,which is positively related to the environmental communication density,and is related to the performance of modules and terminal equipment and other factors;In addition,the PER of the receiver is positively correlated with the environmental communication density and the distance between the sender and the receiver;The ITT is positively correlated with the communication density of the environment;IPG is positively correlated with PER,communication density,distance between communication parties and other factors;Regarding the performance of the receiver,the performance of driving in the same direction is better than that of driving in the opposite direction,and the performance of driving closer is better than that of driving farther;It has been verified that the vehicle trajectory prediction algorithm based on BSM is basically consistent with the actual test results.