On-line conformance testing of the Communication-Based Train Control (CBTC) system

As metro systems have become more advanced, Communication-Based Train Control (CBTC) has been increasingly valued because of its characteristics. It is, however, necessary to guarantee that the CBTC system is safe so that the safety of the whole metro system can be improved. Traditional off-line testing methods are widely used to determine whether the CBTC system complies with the desired specification, but unfortunately these testing methods are becoming insufficient due to the growing complexity and wider functional coverage requirements of the system. In particular, off-line testing methods ask for a deterministic system while the CBTC system is usually non-deterministic. To solve the problem, we propose an on-line testing method, based on a micro railway simulator and the testing tool UPPAAL-TRON, by generating and executing test cases simultaneously. Firstly, we applied the theory of Timed Automata (TA) to model a general routing procedure of the CBTC system. Secondly, the observable abstract variables in the TA-based model were mapped to the simulated variables in our micro railway simulator and the simulated variables were connected to the SUT's variables. Then, we processed the TA-based model via a black-box conformance testing tool UPPAAL-TRON to generate and execute the test case simultaneously. Finally, we analysed the testing results to determine the test coverage and to find out whether there are inconsistencies between the SUT design and its testing specification.