The Research And Design Of Digital Baseband System Based On DPMR Protocol

Along with the development of the voice processing technology and ICtechnology, the modern voice communication system is constantly evolving fromanalog to digital, that tend to use the system solution of software radio. The wirelessinterphone which plays an important role in the command scheduling, management,and other private network communication, is also being gradually transition todigital, providing people with a higher quality, richer business to meet the needs ofthe practical applications.This thesis mainly studies the baseband section of digital interphone system,including voice vocoder, the wireless transmission protocol software design and thebaseband hardware platform design. Firstly, introduce the architecture of the entiresystem, and then analysis the main part of software algorithms, including thevocoder module and the communication protocol stack processing. Among them,selecte the MELP algorithm as the vocoder module to achieve the collected voicedata compression encoding, then analysis the vocoder parameters extraction, speechsynthesis and so on related technologies. Use the DPMR standard as thecommunication protocol which proposed by the ETSI, then analysis the keytechnologies used in the protocol, such as4FSK modulation and demodulation,channel error correction coding, synchronization technology, etc. Secondly, designand optimization the software function module around channel codec, voice codecand transport protocol from the digital interphone baseband in the DSP platform,which combined with the performance requirements for baseband system, scalability,and other aspects taken into consideration. With TI’DSP TMS320VC5509as thecore processor designed the data acquisition circuit and other hardware modulecircuit for baseband system, establish the baseband hardware platform. Finally,transplantation and optimization the MELP vocoder and DPMR protocol in thebaseband platform, then performance testing of each module and joint debugging forthe whole baseband system. Through debugging, baseband system can correctly for the speech dataacquisition, processing and playback. The system successfully implement the MELPvocoder, channel codec, baseband modem and so on, completed the point-to-pointcommunication on both sides.