Design And Implementation Of Az Interface Test Cases In TETRA Digital Trunked System

TETRA digital trunked standard is an open digital trunked communication system standard and is very popular all over the world at present, and the standard is designed and developed by ETSI (European Telecommunications Standards Institution). TETRA digital trunked standard developed by ETSI is mainly used for terminal side protocols, and there is no uniform standard in the infrastructure side of the TETRA digital trunked system. Testing to the system protocol implementation can ensure the reliability of the self-developed TETRA digital trunked communication system, and is of great significance.The Mobile Switch Center (MSC) of TETRA digital trunked communication system is connected with Base Station Controller (BSC) by Az interface, and its functions are terminal registration and the call of the registered terminals. TTCN-3is widely used in protocol conformance testing, interoperability testing, capability testing and so on. The protocol conformance testing of the Az interface based on TTCN-3is the important part of the protocol conformance testing in TETRA digital trunked communication system.Firstly, the development status of the protocol testing is summarized in the paper, and the related theory of the protocol testing is expounded, and the characteristics and advantages of TTCN-3standard test language are analyzed, and the structure of TTCN-3test system is analyzed in detail. Then, based on the analysis of the air interface protocol and Az interface in the TETRA digital trunked system, the functions of the CMCE entity and MM entity such as individual call, group call, short message transmission, group management, registration’and so on in the MSC side are deeply researched, and the functions and signaling format of the Az interface are analyzed in detail, and the Az interface can realize the functions of signaling transmission and service transmission. According to the features of TTCN-3test system, the configuration of the test system and the design of the internal structure are completed, and the test cases are run in an MTC or the test cases are run in a PTC controlled by MTC. Finally, based on the signaling procedure in MSC side, the design of TTCN-3modules, data types, ports, component types, timers, functions, module parameters and test sequence for test cases such as group management, registration, individual call, group call, short message and so on are completed. According to the hardware and software environment required and LoongTesting test system based on TTCN-3, the test platform is built. The conformance testing on MSC protocol of TETRA system is performed by using the remote testing method, and a detail analysis of the conformance test results is given based on the testing verdict.