Research On Vehicle Node Communication Technology For Transportation Cyber-physical System

Transportation Cyber-Physical System (TCPS) is one of the important sub-systems ofCyber-Physical System (CPS), which is used in the field of Intelligent TransportationSystem (ITS). It has the characteristic of CPS that computation world and physical worldare deeply integrated, which provides new ideas and directions for the development of ITS,and has aroused more and more concern by institutions and scholars. As the importantdevice for vehicle to collect information of TCPS, vehicle node, remarkablecommunication performance is the important guarantee for timely, accurately, and reliablycollecting information, also is the key method to ensure a safe, stable and efficienttransportation system safe. Therefore, this paper puts the communication technology ofvehicle node in TCPS as the research object, has important research value and socialsignificance.The WAVE protocol is a wireless communication technology witch is appliedexclusively in the transportation field, has advantages of lower transmission delay, bettermobility support, longer communication distance and higher transmission rate comparedwith other wireless communication technologies. Two communication modes of WAVE,WBSS and WIBSS, are suitable for the communication in V2V and V2I respectively. Thispaper, based on the analysis of WAVE protocol in detail, thorough studied the design andimplementation procedures of WSM communication in vehicle node to vehicle node andvehicle node to onboard side unit of TCPS.Firstly，four-tier architecture of TCPS witch includes physical layer, integration layer,information layer and application layer was put forward, and the composition and functionof each layer were briefly described, the characteristics and key technologies of TCPSwere analyzed. Secondly, IEEE802.11p protocol and IEEE1609.4/3protocols, the mostimportant parts of WAVE were introduced. Among them, two communication modesWBSS and WIBSS defined in IEEE802.11p, multi-channel access control mechanismdefined in IEEE1609.4and WAVE Short Message Protocol (WSMP) defined in IEEE1609.3were focus analyzed. Then, the WSM communication realizing process betweenOBU and OBU in WIBSS mode and it between OBU and RSU in WBSS mode weremainly studied. A program used to test the communication performance between OBU andRSU was written，and the antenna height and the speed of the vehicle effect on packet droprate were analyzed on the NCTUns-6.0simulation platform. At last, to solve the multi-hop routing problem in communication between OBU and OBU, a VP-LD algorithm was given,witch selects next-hop vehicle based on the position and communication link duration ofadjacent vehicles. Through the NCTUns-6.0simulation platform, the performance ofVP-LD and GPSR algorithm were compared, and the simulation results show that, theperformance of VP-LD witch proposed in this paper is superior to GPSR, especially onhigh vehicle speed.