Design And Implementation Of Simulation System For Spectrum Cooperation In VANETs

Vehicular Ad Hoc Networks(VANETs)is a key technology for future intelligent transportation systems.The development of mobile communication technology has provided important conditions for the application of VANETs.Network features such as ultra-reliable and low latency can greatly improve the safety and efficiency of intelligent transportation.At present,the intelligent and cooperative use of spectrum between vehicles to transmit various services has become an important direction for the development of VANETs.However,the high-speed movement of vehicle will cause the network topology and communication environment to be highly dynamic.With the increase of connected vehicles,how to effectively use wireless spectrum resources has become particularly important.Spectrum cooperation has become a key technology for dynamically managing the spectrum resources of VANETs.Due to the high cost of external field tests and difficult to reproduce experimental results,simulation of VANETs with spectrum cooperation capabilities is a practical and effective research method.However,the existing simulation software for wireless networks or VANETs cannot support spectrum-level operations.To this end,this thesis designs and implements an integrated simulation system for VANETs that supports spectrum cooperation.This system can import real maps and vehicle motion trajectories,combine the vehicle clustering and spectrum decision-making algorithms,realize the real-time frequency conversion of the physical channel during the network simulation process and statistically display the simulation results in various intuitive ways.The main research work of this thesis is as follows:1.The protocol stack is the basis for the operation of the VANETs and the reference basis for the realization of network simulation.In order to enable VANETs to support spectrum cooperation,a cognitive protocol stack in VANETs is proposed for spectrum cooperation.Vehicles can use the results of spectrum sensing to perform clustering and spectrum decision-making to achieve spectrum cooperation.At the same time,this thesis discusses the design ideas of vehicle clustering algorithm and spectrum decision-making algorithm in the cognitive protocol stack.Compared with the traditional WAVE(Wireless Access in Vehicular Environment)network protocol stack,the cognitive protocol stack fully considers the high-speed mobility of the vehicle,the dynamic characteristics of the network topology,and the dynamic requirements of the spectrum,and provide reference for the research on spectrum cooperation technology in VANETs and simulation technology.2.Under the guidance of the cognitive protocol stack for spectrum cooperation in VANETs,an integrated simulation system for spectrum cooperation in VANETs including traffic simulation,network simulation,spectrum cooperation,and real-time display is designed.The thesis introduces the architecture design of the four modules,the design of their respective interfaces and interior,and the design of the interactive interface between the modules.The system can provide real and effective simulation support for the research of a variety of algorithms including spectrum cooperation in VANETs.3.In order to realize the design that supports spectrum cooperation,the corresponding program of the network simulation software EXata was modified,and based on this,an integrated simulation system including interfaces,function modules,and inter-module interfaces was implemented.The system was verified by setting up simulation scenarios at different periods,and the results show that the simulation system is simple and convenient to use,can effectively support spectrum cooperation,and can statistically simulate simulation results in real time and accurately.The map,vehicle movement trajectory and clustering results are highly intuitive to restore the scene of VANETs.