Design And Implementation Of A Software Platform Based On Digital Private Network Radio Communication System

At present,China's wireless communication network system is divided into public network system and private network system.Private network locates at serving different market from public network and plays an irreplaceable role.The main representative of the private network communication system is interphone communication system.Now in the market,the high cost of digital interphone leads to the final high price.The development of digital interphone market still has a long way to go.The main content of this thesis has designed a software platform of digital private network radio communication system based on dPMR protocol,aiming at designing a simple operating system to cut costs,rather than using an existing generic operating system.Firstly,the thesis has introduced the overall framework of the system,and then been divided into different modules including the protocol stack,the keyboard and screen module,the audio and RF module and relations between them.The protocol stack has achieved functions of the physical layer,the data link layer and the call control layer,focusing on the implementation of the clock extraction algorithm and the design of the state machine and the call control process.The functions of the keyboard and screen module are screen displaying and the parsing and processing of keyboard commands.Functions of voice capturing,playing,data transmission,coding and decoding of the vocoder has been achieved in the audio module.Furthermore the thesis has explained the invoking relationship between audio driver and protocol stack and realized the designing and implementation of data transmission and reception in the RF module.Finally,the thesis has improved the design of the interphone,including the design of analog and digital dual modes,power-saving in sleep mode,and the function realization in engineering mode.The innovation point of this thesis is that the entire software system is equivalent to a customized operating system.All modules in this design are independent and they call each other based on mutual links between them without using the existing common operating system to reduce the design costs.It is proved that the system has achieved the function of point to point communication between the terminals.