Research Of DOA Estimation Method And Implementation For LTE Signal

In recent years,with the rapid upgrade and wide application of wireless communication technologies,various wireless devices have increased rapidly and the electromagnetic environment has become increasingly complex,which has brought new challenges to radio monitoring.In this context,this article studies the method of locating the LTE uplink signal from the perspective of the third party,and implements and validates the key algorithm on the DSP development platform.This paper discusses and analyzes the research status and theoretical basis of the DOA estimation algorithm.According to the goal of the project,we use the MUSIC algorithm in spatial spectrum direction finding technology to perform two-dimensional DOA estimation under the uniform circular array model.Under single source and multi-source conditions,the DOA estimation algorithm program written on the basis of matlab is simulated and verified,and the DSP platform of the algorithm program is transplanted on this basis.The development platform of TI-based TMS320C6670 multi-core DSP chip is briefly introduced,including the functions of each module,software development environment and SYS/BIOS real-time operating system.Migration work includes language conversions,function implementations,and platform-specific optimizations.Using the data generated by matlab on the DSP development platform to validate the DOA estimation algorithm after transplantation,the 2D DOA value of the target source can be accurately estimated,namely the depression angle and the azimuth angle,and the correctness of the transplantation work is verified.At the same time,the evaluation of the resource overhead was performed on the transplanted program,which verified the feasibility of the transplant program.When a third-party device performs direction finding on a target user,there are problems in that the co-channel interference and the user uplink signal arrival at the third-party device are not synchronized,this paper proposes to use the cross-correlation of the demodulation reference signal in the PUSCH channel,using the cross-correlation between the locally generated demodulation reference signal sequence and the demodulation reference signal sequence received by the antenna to solve the problem.For this reason,a method of generating a demodulation reference signal sequence in a PUSCH channel is studied,and a ZC sequence,a pseudo-random sequence,and a base sequence used in the generation process are introduced.Finally,the matlab and C code that generates the demodulation reference signal sequence are programmed to obtain the peak value in the energy spectrum through cross-correlation simulation to determine the target user's used resource location and eliminate the same frequency interference.The study of DOA estimation and the implementation on DSP development platform,as well as the cross-correlation simulation of demodulation reference signal in PUSCH channel have certain significance and value for radio monitoring.