Research And Implement Of Demolution Of TD-LTE Downlink

The thesis is concentrated on the research and realization of carrier recovery for digital phase modulation signals based on “Research on Digital Modulation Signal Test and Analysis in Hybrid/Heterogeneous Network”,which belongs to the project of the national key scientific instrucment and equipment development “Research and Application Development on High Performance Spectrum Analyzer”.The timing synchronization algorithms,correct frequency offset algorithms and channel estimation algorithms for TD-LTE downlink signal are studied and the major functional modules of modulation are designed and implemented.Considering the project targeting on recriving TD-LTE signal conforming follow 3GPP standard by achieving accurately synchronizing the timing and frequency and estimating the channel in the downlink.The main contributions are listed as follows:1.Timing and frequency synchronization of the receiving signal of TD-LTE downlink.Several algorithms are discussed.According to the futures of the downlink signal in TD-LTE system,the timing synchronization performance of the autocorrelation,cross correlation and piecewise correlation algorithms based on primary synchronization signal.The frame timing is realized by the peak detection based on the partial correlation algorithm.Frequency offset estimation and compensation are realized based on the correlation of parmary synchonization signal and cyclic prefix.The effect of inter carrier interference on the receiving signal is reduced.2.Channel estimation of the receiving signal of TD-LTE downlink are discussed.Reference signal based algorithms and LS algorithms and MMSE algorithms are discussed and compared.Concemed the complexity in realization,the performance of channel estimation,in order to tackle the problem of multipath effect,suitable algorithm for engineering application is designed.Through the detection of reference signal,and it is estimated by MMSE and the Discrete Wavelet Tranform.In the downlink data position,frequency domain Discrete Cosine Transform cascade connextion with Lagrange interpolation is used.3.Implementation and test of TD-LTE downlink demodulation system.According to the requirements of the project agreement,the design and implementation of the TD-LTE downlink signal test and analysis module is completed by C language.The test platform of TD-LTE downlink is built,then,test and analyze the real-time data.The result show that,the same environment,the test paramters of this system are compared with Agilent 896000 VSA,the key indicators of are close.The analysis can fulfill project parameter requirements well,and verificate the performance of system and algorithms.