Research On Optimal Interface Selection And Switching Algorithm For C-V2X

The improvement of science technology and social economy has developed the automobile industry and manufacturing technology,which pushed Chinese car ownership to spring up and the owners’ further requirements for in-vehicle applications.From the initial“electronic dog” to the current in-vehicle multimedia,these applications need the support of the Internet of Vehicles.Because of constant moving of these vehicles,cellular Internet of Vehicles is characterized by its high mobility,heterogeneous network structure and complexity of network topology.In this way,different communication interfaces need to be used in different scenarios,and their switching and selection will be involved in this process.The communication interfaces of cellular V2X(Vehicle to Everything)include PC5 port and Uu port with different characteristics.Their ability to achieve seamless interface switching and optimal interface selection is a key factor in meeting vehicular applications.Therefore,this thesis takes the above contents as the research objects.In the scenario where LTE network and NR network coexist,UE(User Equipment)could use four types of interfaces,including LTE Uu,LTE PC5,NR Uu,and NR PC5.These four interfaces have different characteristics and performance and these features could vary with different scenarios,so it is necessary to research how to choose an optimal interface to send data in different scenarios.In response,this thesis will propose TOPSIS(Technique for Order Preference by Similarity to Ideal Solution)algorithm based on the fuzzy analytic hierarchy process,according to the characteristics of different communication interfaces,in order to solve the problem of optimal interface selection for different types of messages in5 G cellular V2 X based on LTE and NR.The whole process of selecting the optimal interface is mainly composed of three parts — pre-screening,weight analysis of decision factors,and optimal interface selection.The decision factors of this algorithm are data rate,CBR(Channel Busy Ratio)and RSS(Received Signal Strength),and this algorithm belongs to a multi-factor decision algorithm;then,the weight vector of these three decision factors can be obtained through fuzzy analysis,and the weighted standardized decision matrix can be obtained by correspondingly multiplying the weight vector and the decision matrix;finally,the TOPSIS algorithm can be used to obtain the optimal interface.According to the simulation results,this algorithm has obvious advantages in the optimal interface selection success rate,and it can greatly increase the throughput of the communication system and improve the system capacity compared with the single factor algorithm based on CBR and RSS.When the UE selects different interfaces for vehicle-to-vehicle communication at different times,it needs to switch between different interfaces.Due to the high latency of interface switching in a high-speed environment,this thesis will analyze the interface switching that may occur in several typical interface switching scenarios,give the guidelines and process schemes for interface switching,and evaluate the time delay of the interface switching scheme.The evaluation results show that the interface switching scheme proposed in this thesis can basically meet the delay requirements of V2 X seamless switching.