Design And Verification Of Communication Protocol For Onboard-Trackside Equipments In CTCS Level 3

With the rapid development of the China Railway Industry, the requirements for train operating control system are becoming more and more rigorous. That CTCS level 3 train operating control system onboard-trackside equipments communicate by using GSM-R is to fulfill the high-speed railway requirements. Because the GSM-R communication system can't fulfill the high level safety requirements of train operating control system perfectly, we need a communication protocol for onboard-trackside equipments which can play a role on raising the safety performance and reliability in data transpfort respect.In this paper, the designing and researching of safety-related communication protocol for CTCS level 3 onboard-trackside communication system (abbreviation: CTCS level 3 communication protocol) has been completed. In the first place, the CTCS level 3 requirements for communication protocol has been analyzed from two points of view: The first angel is analyzing the train operating control system requirement for communication system based on the communication process of onboard-trackside equipments in CTCS level 3; The second angel is analyzing the requirements for CTCS level 3 communication protocol according to the GSM-R transmission system QoS requirement in CTCS level 3. In the second place, according to the EN50159-2 system standard which about safety-related transmission, some demands in order to protecting potential safety hazard have been made.Then according to requirements, CTCS level 3 communication protocol is designed. ETCS has accumulated much experience in GSM-R application, and ETRMS has made the European Radio Function Interface Specification (EuroRadio FIS) which describes the means of designing the communication protocol based GSM-R. So we can design CTCS level 3 communication protocol, according to some items in EuroRadio FIS that can fulfill the requirements of CTCS level 3 communication protocol. And then we can optimize the design result for some requirements EuroRadio FIS can't fulfill. By this way, we can make sure that the safety-related communication protocol not only attaches the target to inherit some achievements but also fulfill the requirements from CTCS level 3 and safety-related communication standard EN50159-2.The communication protocol are improved on the basis of the EuroRadio FIS, so we need to analyze the functions and capabilities of CTCS level 3 communication protocol by some formulization analysis means, in the design stage. Then the guarantee of correctness and usability can be taken out. In the paper, CPN is select to model CTCS level 3 communication protocol and EuroRadio FIS. And the "CPN tools" is used to validate the status space feature and other capability. Especially, by comparing these two models, it can be validated that some special capabilities of CTCS level 3 communication protocol are better than of EuroRadio protocol. At the end of the paper, the conclusion is that CTCS level 3 onboard-trackside communication system safety-related communication protocol, researched and designed in the paper, is fulfill the requirements of CTCS level 3 and can be put into useing.