Implementation Of LTE Link Level Simulation Platform And Reaserch On Cell Search Algorithm

As the primary process of cell search, the main physical layer process in the cell initial search phase is the initial frequency scanning of the downlink and the judgment of the center frequency position of cell. With the continuous development of LTE system, LTE and its evolution system will coexist for a long time in the evolution route of future mobile communication, and integrate with other wireless broadband technology closely.This topic comes from Model Certification Department, CTTL of the Ministry of Industry and Information Technology, "Search and Selection network of Mobile Terminal." In the initial stage of cell search, the power spectrum estimation algorithm is of great significance: as the core algorithm of the initial search phase, the performance of power spectrum estimation algorithm is directly related to whether the terminal can successfully access the optimal cell, and it will largely affect the quality of communication services. In the low signal-to-noise ratio (SNR) channel environment of LTE and future mobile communications, the performance of traditional power spectrum estimation algorithms has dropped dramatically, which is no longer applicable to this application scenario. In this paper, the power spectrum estimation algorithm under low signal-to-noise ratio is studied.Firstly, the process of cell initial search is introduced. The power spectrum estimation algorithm and its performance are analyzed in detail,and the main challenges in the current power spectrum estimation algorithm are pointed out. Then, the LTE link-level simulation platform is set up. In the design and implementation of the simulation platform, the idea of dividing the flow into functional modules is used to complete the signal sending and receiving and cell initial search functions. The simulation results of the platform show that the proposed LTE link-level simulation platform can complete the process of cell initial search well and provide the basic platform for algorithm realization and performance analysis for the next research of power spectrum estimation algorithm.Finally, the algorithm of power spectrum estimation in cell initial search is studied. Wavelet analysis is used to clear the direction of denoising, and then to estimate the power spectrum, wavelet threshold denoising, signal reconstruction, power spectrum estimate. The simulation results show that the proposed algorithm can effectively reduce the false probability of the center frequency of the cell and improve the accuracy of the frequency point judgment, and has a very good performance under low signal to noise ratio. Finally, a further improvement of wavelet threshold denoising method is given.