The Design And Realization Of LTE Uplink Time-frequency Synchronization And Equalization

Aiming at the design and realization of LTE uplink time-frequency synchronization and equalization,the thesis is supported by the task “Research on Digital Modulation Signal Test and Analysis in Hybrid/Heterogeneous Network” belonging to the national significant scientific apparatus project “Research and Application on High-Performance Spectrum Analyzer Development”(2012YQ20022404),in which the subtask requires “Solution for the TD-LTE signal Test and Analysis”.The time-frequency synchronization algorithms and channel equalization algorithms for LTE uplink signal are studied and the performance test of modulation are designed and implemented considering the project targeting on receiving TD-LTE signal conforming with 3GPP standard by achieving accurately synchronizing the timing and frequency and equalizing the channel in the uplink.The specific contents are as follows:1.Timing synchronization of the receiving signal of LTE uplink.Several algorithms are discussed.According to the features of the uplink signal in LTE system,the timing synchronization is achieved by searching for the maximum peak in the correlation detection between the local reference signal and the received signal since the CAZAC properties are within the reference signals generated from Zadoff-Chu sequence.Combining with the CP correlation detection,the accuracy of the timing synchronization is enhanced.2.The Frequency synchronization of the LTE uplink signals.Cyclic prefix based algorithms and Schmidl-Cox frequency offset estimation algorithm based on training sequences and algorithm based on demodulation reference signals are discussed and compared.Concerned the complexity in realization,the range of frequency estimation and the accuracy requirement of signal demodulation,in order to tackle the problem of multipath effect,the local reference signal based correlation detection algorithm are designed and implemented for the realization of frequency offset estimation.3.The equalization of the uplink in LTE uplink channels.After comparing the conventional single carrier transmission mechanism with multi-carrier system,the differences of channel equalization methods in between are interpreted and explained.In the design and implementation of the uplink estimation,the frequency domain equalization based on channel estimation are preferred with the channel response sufficiently estimated in the LTE system uplink to compensate the non-ideal characteristics of the channel and eliminate the inter-symbol interference caused by imperfect channel thereby.4.Testing and analyzing the vectorial errors of modulation parameters.Through calculating and analyzing the error parameter between measurement signals and reference signals,a general test and analysis framework for LTE uplink receiving signals is established and the test environment is built and goals of accurate reception,test and analysis are achieved.The results of LTE uplink signals test and analysis are compared with target product and benchmarking.It is manifested that the performance indexes of the implemented module are closed to that of Agilent VSA89600 the target product.