Software Design And Implementation Of Vehicle To Vehicle Communication Terminal System Based On WAVE Protocol

This thesis discussed a kind of vehicle to vehicle communication terminal system based on WAVE(Wireless Access in Vehicular Environment)protocol stack.In the scene of emergency vehicles,the front emergency brake and crossing warning,vehicles can share information through this system,to reminder drivers to take the most favorable reaction immediately towards various traffic situation,which can effectively avoid the traffic accidents.At present,the studies on vehicle to vehicle communication in domestic and abroad mainly focus on theoretical research and simulation analysis.The study on system development is quite rare.The system designed in this paper is helpful to the study and development of vehicle to vehicle communication system.The hardware platform of this system is consisted of ARM Company's Cortex-A7 that is the main processing unit(MPU),and the peripheral circuit.The wireless module is working at 5.9GHz frequency band to support the WAVE standard.In view of the vehicular environment's requirement of low latency and high performance,it is suitable to choose the QNX real-time operating system as the software development platform,focus on finishing the development of wireless network driver and daemon process.The main research content is as follows:(1)Start from the vehicle to vehicle communication system's application scenario,the author mainly discussed the functional requirement and system requirement.Then the author analyzed the operation system framework of QNX according to the system requirement,which provides theoretical support for the software design of vehicle to vehicle communication system.(2)In view of the QNX's network framework,this paper adopts the “top half” design mode that is based on io-pkt for the access of application program.In order to achieve the upper layer's configuration to the wireless module,it adopts a non-blocking message delivery mechanism to design the command channel of driver and daemon process,which can avoid system disorders effectively.Based on the command channel,it designs the data channel of driver and daemon process,respectively for IP data and WAVE short message.In order to meet the transmission requirements of different channels,this thesis presents a double channel design mode,which is respectively applied in transmission safety business and non-safety business.(3)The design of daemon aims at finishing the information interaction between handheld device and driver.In order to realize the handheld device's control on vehicle-mounted mainboard,this thesis adopts client/server development model.Daemon process is the sever-side,and handheld device is the client-side.According to functional requirements of daemon process,adopting the modularization design approach,it divides the daemon process into several parts: data receiving module,data processing module,data sending module,heartbeat packets detection module,statistics module,GPS module,and Log module.These modules coordinate and cooperate with each other.Construct system testing environment,to test the function and stability of the vehicle to vehicle communication terminal system.The test result indicates that the system in this thesis has reached the expected requirements.It can realize the communication among vehicles under the environment on board and the system is stable and reliable.