Design And Implementation Of Non-blind Fast DOA Estimation Method For Mobile Communication Terminal

With the development of mobile communication technology,there is a growing demand for mobile terminal positioning from Io T and other industries,and from public security department as well.The demand for wireless positioning of mobile communication technology has brought new research hotspots.Therefore,the non-blind DOA estimation method for mobile communication terminals is studied in the thesis.The non-blind DOA estimation method and its improved algorithm is deeply studied.The algorithm for uplink signals of mobile communication terminals based on the third-party receiver is designed and improved.Based on the LTE-A uplink signal,the algorithm is verificated and implemented.The main works are as follows:1.The antenna array receiving model commonly used in DOA estimation is studied.The significant technologies in the LTE-A system are studied,and the implementation of its uplink reference signal is analyzed,which provides a non-blind DOA estimation method for LTE-A.Theoretical basis.2.The basic non-blind DOA estimation algorithm is studied,and the principles of classic LMS algorithm and variable step LMS algorithm are described.Based on the design principles of the variable step size LMS algorithm,the improved variable step size LMS algorithm is proposed,which combines sigmoid function,normalization,feedback.The simulation experiment on it is carried out.The result shows that the convergence speed is superior to the rest of the algorithms,and the superiority of the algorithm against interference in special scenarios such as signal fluctuations and channel environment changes is tested.3.The difficulties faced by third-party receivers based on uniform circular arrays for DOA estimation are analyzed,and the uplink signal array receiving model of third-party receivers is derived based on actual scenarios.At the same time,the generation of reference signal DMRS and its simulation implementation are studied.Based on the upstream received signal model,the main algorithm of the third-party non-blind DOA estimation for mobile terminals is proposed,and the non-blind DOA estimation algorithm is improved accordingly.Based on the LTE-A uplink signal,the simulation experiment is carried out.The simulation results show that the algorithm can effectively overcome the inter-symbol interference problem caused by the third-party receivers,and is superior to other algorithms in the accuracy of the estimation result.Therefore,the DOA estimation algorithm based on indoor scenes is proposed,and the superiority of the estimation results is proved through simulation experiments.The main energy attenuation threshold of the algorithm is further studied.4.The algorithm is transplanted on the GNU Radio platform.The simulation algorithm is rewritten by C ++ language,and the algorithm is verified using the simulation signal.The flow chart of the algorithm under GNU Radio is further proposed,and the verification and optimization schemes are given.