The Research On The Repeater With DPMR Standard And Implementation And Application Of The Wired Interface

Digital trunking communication system gradually becomes the mainstreambecause of the advantages over the analog trunking communication system, such ashigher spectrum efficiency, stronger ability to resist channel fading and betterconfidentiality. To tie in with the development of the digital trunking communicationsystem, multiple standards of digital technology have been launched at home andabroad, including dPMR standard by European Telecommunications StandardsInstitute in2005, which has the advantages of high spectrum efficiency, low technicalthreshold and low cost terminal and so on, and is a good way to support the transitionof trunking communication system from analog to digital.In this dissertation, the two parts of the key technologies including modulator anddemodulator and numerical controlled oscillator, as well as its implementation andapplication of wired interface are mainly studied based on repeater of dPMR standard.Firstly, aiming at the problem of the phase error estimation induced by the differentialphase detection under low sampling rate, an improved differential phase detection isproposed through a multistage linear approximated theoretical phase value, andsimulation results demonstrate the improved differential phase detection caneffectively reduce the influence of the phase error estimation under the condition ofnot obvious increasing the computational complexity. Secondly, aiming at theproblem of the intersymbol interference induced by the demodulation with harddecision decoding, the improved decision method with dynamically judgmentthreshold according to the associated elements is proposed, and simulation resultsdemonstrate that it can effectively reduce the intersymbol interference, and improvethe transmission performance of the system. Thirdly, aiming at the problem ofcomputation complexity of numerical controlled oscillator based on CORDICalgorithm, an improved CORDIC algorithm is proposed, and theoretical analysisconfirmed improved algorithm can effectively simplify the computation complexityunder the condition of not obvious reducing the precision of output. Finally, based on the repeater with dPMR standard, the data transmission with the external equipmentis realized through the wired interface, and through the analysis of existingscheduling software structure, the scheduling management software of the repeater isdesigned and implemented based on dPMR standard, and the aim of informationmanagement of mobile terminal and GPS position is realized.