Complete Of The Digital Trunking Terminal Protocol Stack Based On Omap3530

Digtal trunking mobile communication system is an advanced command and dispatch system, which also is an important part of the special mobile communication system. Currently, the technology of analogy trunking mobile communication has no longer met the market demand. Digital trunking communication system is becoming an advanced wireless command, liaison, dispatched communication system with the features of efficient and low-cost, because it has higher spectrum efficiency, greater system capacity, better communication quality and can provide simple operation, flexible network management, confidentiality, ability to multi-level grouping, etc. In the field of shipping traffic, public security and fire department, defense and military, also treatment of any other major emergencier, the digital trunking mobile system is receiving more and more considerable attention and application.In the case of the current smart phones with the competition of its configuration and functions, digital trunking handheld terminal in communication and dispatching functions of the emergency period, which played a huge role in the recent natural disasters of Ya’an earthquake. Digital trunking mobile phone design has been fully taken the harsh environment and unconventional usage into account, include of waterproof, dustproof, shockproof design, also made a nonslip handle design in mobile structure, and always provides the function of the GPS(global position System), etc. So under the circumstances of the local power, communication system and other aspects which has been seriously damaged, it has a great relief personnel scheduling and good information transmiting to ensure that relief operations to implement smoothly.The CNTM clusters standards is customized in accordance with the needs of a department of our military, which also has a reference to the TETRA protocol architecture and is independently designed based on "OMAP and FPGA" multicore chip platform of the digital trunking mobile communication system. This paper first summarize the development of history, status and the development trend of the digital trunking system, then it has an analysis in the overall structure and hierarchical model of the digital trunking air interface protocol stack, functional interface and other key concepts, also has comparison of four different synchronization technology between base station clock and time, and introduce the air interface baseband signal processing model and principle block diagram.Secondly, because of the system will choose the different type of the channel-codec according to different type of the logical channel, and then this paper specifically described these algorithms based on D-MAC player, includes Cyclic Redundancy Checks (CRC) check code, Reed-Muller error-correctiong, Rate compatible convolutional code and its corresponding Viterbi decoding, interleaving, scrammber code and so on, and then carry out one proper way to realize these models. Then, it analyses the evolution of the GMSK modulation technique and its basic principles, and implements the circuit of modulator based on FPGA model of Altera Cyclonell EP2C50F48418. The Gauss filter is implemented based on lookup table and the orthogonal modulation signal is generaterd by CORDIC(Coordinate Rotation Digital Computer) algorithm in GMSK modulator circuit, so the circuit is simple, adjustbale and flexible. It passes the Modelsim simulation and is verified by FPGA successfully, and has been applied in commericial products of the CNTM trunking communication system.Finally, the paper has a brief elaborate about digital trunking terminal hardware platform, decribes the hardware and software architecture of the OMAP3530and FPGA, focuses on the key technologies—it has the anaylsis and comparison of the communication mechanism between the three cores based on ARM, DSP and FPGA. Then, this issue provides a structural model diagram of the overall software system of CNTM communication system, by describing the mobile terminal how to send the baseband signal of the uplink data in DSP processing software system, and the inverse process of its base station’s receiving. In this place, it will detailed analysts of the data sent from the client to parse the package on the ARM side by the end of upper data, and then through the channel processing, channel multiplexing, to be a burst that is sent to the RF and its inverse process. It gives some parts of the package strcture between ARM, DSP and FPGA, also with its processing functions. At last, the author sum up the principal ideas of the whole dissertation and the directions of the further research.