Key Technologies Research Of Transform Domain Communication System Based On Time-frequency Analysis And Modulation Of The Pseudo-random Phase

In order to improve the utilization of the limited spectrum resources and thecommunication quality,the transform domain communication system is proposed.Thesystem proposes a new idea about inhibiting interference.Within a given systembandwidth,at the transmitter and the receiver to compose basic modulation waveformdynamically which is not contain the interference(or the users are using)to modulate andreceive data.This will take the initiative to avoid channel interference,and enhance theeffectiveness and reliability of the communication system greatly,also makes the systemwith low detectability and low intercept.At present,the study of transform domain communication system are not considerthe influence of the measurement noise from the spectral estimation when estimate thechannel.This paper focuses on modern mutual-spectral estimation theory and methods tosuppress the measurement noise in the spectrum of the channel estimation,therebyimproving the quality of communication.Firstly,this text introduce the composition and the basic principle of the transformdomain communication system,and then study the theory and methods of the spectralestimation (include the self power spectrum estimation and mutual power spectrumestimation).Secondly,propose the Levinson algorithm and the SVD algorithm all based onthe mutual-spectral AR model parameters and study the amplitude spectrum of themolding method,the pseudo-random phase generation algorithm and modulation methods.Finally,using MATLAB software to build a simulation platform of transform domaincommunication system,and verify that the colored noise background,the TDCS use theLevinson algorithm and the SVD algorithm all based on the mutual-spectral of ARmodel parameters estimated can effectively suppress colored noise,while compare withthe Direct Sequence Spread Spectrum,and verify that the TDCS has a strong suppressionfor single-tone interference,multi-tone interference,10%narrow-band interference and70%narrow-band interference.