Research Of LTE System RF Signal Parameter Estimation Method

With the rapid development of LTE communication technology,a large number of LTE network device has appeared in the practical communication network,nevertheless,the LTE signal wireless testing technology is still an important issue that must to be solved.The core technology of LTE test instrumentation is the radio-frequency(RF)signal parameter estimation,there are important significance for managing radio spectrum,preventing illegal use and illegal occupy the spectrum,and ensuring that the legitimate user normal communication and efficient use of spectrum resources.Therefore,it is very important to study the RF signal parameter estim ation method for the LTE system.This article study in depth the LTE downlink signal parameter estimation algorithm,the main results obtained are as follows:1.In order to facilitate the simulation experiment of the parameter estimation algorithm,the LTE downlink signal simulation platform is built by using MATLAB software according to the relevant protocol of 3GPP 36 series.The model can be used to produce LTE downlink simulation signal according to the standard,and adjust the modulation type,signal-noise ratio,carrier frequency,signal bandwidth and so on.The model can satisfy multiple needs of the LTE signal parameter estimation algorithm simulation.2.In this paper,we make a full investigation and research on the existing parameter estimation algorithms,and propose a more excellent parameter estimation algorithm based on the existing problems and the characte ristics of LTE signal.The carrier frequency estimation scheme is divided into coarse estimation and accurate estimation of two parts through introducing the idea of least squares,carrier frequency offset estimation scheme for coarse estimation and fine estimation,it makes the performance of the algorithm has a huge improvement.After introducing the idea of local linear fitting based on the original bandwidth estimation algorithm,the algorithm overcomes the defects of the original algorithm to the noise sensitive.In addition,based on the design of bandwidth estimation algorithm,a detailed design scheme of the transmission power estimation algorithm is proposed.The proposed parameters estimation algorithm not only has a very good performance,the optimization of the time complexity is carried out as far as possible from the point of view of engineering implementation when the algorithm is designed.The experimental results obtained on the LTE downlink signal simulation platform are analyzed,and the proposed algorithm has better performance than the traditional parameter estimation algorithm.3.This paper not only presents the design idea and performance analysis of the estimation algorithms of the parameters,but also provides the overall design scheme and implementation scheme of a complete parameter estimation system,finally the key data structure and interface definition are given.In order to make full use of FFTW open source library to achieve power spectrum estimation,this paper also according to the implementation of the program to complete the detailed code written in C languag e and debug process.Under the condition of ordinary single computer experiment,the demand of the amount of a million level of data operations,the implementation of the proposed scheme to complete all the parameters of the algorithm is only less than a second of time consumption,fully able to meet the requirements of real-time performance of the algorithm in the field of wireless monitoring.If the proposed parameter estimation algorithm is transplanted to DSP and other hardware,the use of multi thread technology or DSP thread pipelining optimization to speed up its operation speed,it will able to complete the parameters estimation with higher level data.Therefore,the implementation of the proposed parameter estimation algorithm in this paper has a very good feasibility in practical engineering.