The Design And Implementation Of Trunk And Radio Interface Board

Trunking communication system is a dedicated and private system. It has thecharacteristics of integrated dispatching and emergency command communication (suchas push-to-talk, emergency call and the group call). With the development ofdispatching and emergency communications, the trunking system is more and morewidely used in the logistics, public security, fire, transportation, forestry, and manyother industries. Along with the development of trunking network increases, the demandof the network interconnection is growing day by day. Due to the departments such aspublic security, fire and others using of different trunking communication system,network integration is a scheduling problem.This paper analyzed the interface characteristics of different trunkingcommunication systems, propound a unified connecting solution based on the audiointerface, then design and produce the integrated switching and scheduling equipment.This paper mainly discusses the trunk and radio interface board design, which used inthe integrated switching and scheduling equipment. Each trunk and radio interfaceboard provided four trunking or radio interface. It can realize four different bands,various technical trunking system connecting with each other. It can also connect theradios to realize interconnection between trunking and radio systems. With datainteracting between the trunk and radio interface board and two wires board which inthe integrated switching and scheduling equipment, can also make trunking privatenetwork access the public switched telephone network (PSTN) and GSM/CDMAmobile network, making the smooth communication between duplex devices andsimplex devices. It solved the problem of the different departments can’t unifyscheduling and commanding.Trunk and radio interface board due to the size and cost control, the design of thehardware architecture is based on SOPC, using ALTERA’s FPGA and the inner isconstructed a NIOS II processor platform. In addition to voice codec by using ASICchip, the rest of the data processing and control are accomplished in FPGA. The main work of this paper is described below:1. Designed a hardware system of trunk and radio interface board, including thevoice interface circuit, speech coding and decoding circuit, FPGA subsystem and hotplug interface circuit and so on, has completed the hardware schematic diagram designand PCB layout.2. Completed the FPGA logic design and software development. For the design oftrunk and radio interface board has encountered in voice active detection (VAD) andDual Tone Multi Frequency (DTMF) detection two key algorithm, first using the Matlabsimulated, then using VHDL hardware description language Implementing the twoalgorithm, and use the ModelSim software to simulation, adjusted by modifying thetiming, to ensure that the program design is correct. After the FPGA logic programanalysis, synthesis, fitter and assembler then downloaded into FPGA, and usingSignalTapII Logic Analyzer tool validated the program algorithm. The program of thealgorithm are all realized by the FPGA internal basic logic unit, away from the FPGAinternal multiplier special logic, so that the two algorithm of the IP core are for allFPGA platforms, convenient for other products using.3. By an integrated hardware and software debugging and verification, eventuallythe equipment has been equipped police, civil air defense and other departments and hasbeen praised by users. DTMF detection IP core also ported to XX speaking andcontrolling equipment and other equipment. The practicability has been further verified.