Research And Development Of SubNetwork Dependent Convergence Protocol Layer In TETRA Digital Trunked System

With the development of TETRA digital trunked communication in our country, the requirement for TETRA digital trunked system equipment will be increasing step by step. The TETRA digital trunked system equipment, which are made by foreign manufactures, are too expensive, and ordinary people can not afford them. Therefore, it has practical significance to develop TETRA digital trunked system equipment which has independent intellectual property rights.SubNetwork Dependent Convergence Protocol is the network layer protocol of TETRA digital trunked system, and is also the core of TETRA digital trunked system packet switched domain. SNDCP is responsible for the mapping of packet data services in network onto the air interface. It provides many packet data services, such as photographs transfer, E-mail, web browser, global position system service and provides radio dispatching applications for wireless subscribers. Therefore, the development of SNDCP layer is the key of the development of protocol stack in TETRA digital trunked system.The thesis summarizes the technological characteristics of TETRA digital trunked communication system and its developing situation at home and abroad, and TETRA digital trunked system Softswitch architecture is given according to the trend of TETRA digital trunked system. The thesis analyzes the design and implementation principle of TETRA digital trunked packet system domain in detail. Based on Telelogic Tau G2 integrated development environment, the procedure of implementation from the SNDCP module design to the programming is fulfilled by using method of mixed-language programming between UML and C. The functions such as PDP context activation and deactivation, packet data channel set-up, packet data compression and packet data paging mechanism are developed independently, and the protocol conformance tests are accomplished. The test results are in accordance with "ETS 300 392-2 TETRA V+D Part 2: Air Interface" and satisfy the design requirement completely.