Research On Key Algorithms Of 5G Cell Search And FPGA Implementation

The 5th Generation Mobile Communication(5G)has been commercialized,and countries all over the world are stepping up the construction of 5G base stations.At present,the Release 16 version of the 5G standard has been frozen,and the new version improves the support for scenarios such as Ultra-Reliable and Low Latency Communication and Vehicle to Everything.However,most 5G terminals currently do not support these scenarios,and most 5G base stations still work in the enhanced Mobile Broadband(e MBB)scenario of Release 15."e MBB 5G UE Simulator" is a 5G terminal device whose purpose is to simulate the functions of 5G User Equipment(UE)and receive and process 5G downlink signals to test 5G base stations.Cell search is the first step after the UE is turned on,and its performance has a vital impact on the entire 5G terminal system.This thesis studies the synchronization algorithm and channel estimation algorithm in 5G cell search,and then according to the needs of the project,the entire cell search module is implemented using Field Programmable Gate Array(FPGA).The main work and innovations of this thesis are as follows:1.Based on the third-order correlation properties of m-sequences,this thesis proposes a primary synchronization signal fine synchronization algorithm.The results of the simulation are that when the signal-to-noise ratio is as low as-7d B,the detection accuracy of the third-order correlation algorithm is about 32% higher than that of the traditional algorithm.At the same time,the third-order correlation algorithm does not increase the space complexity compared to the traditional algorithm,and the time complexity is 129.67% higher than that of the traditional algorithm.2.Aiming at the channel estimation of the non-reference signal position in the Physical Broadcast Channel,this thesis proposes to use the fitting method instead of the traditional interpolation method for channel estimation.Thesis studies the application method of fitting in the channel estimation,and give the best fitting function under the Additive White Gaussian Noise(AWGN)channel.Finally,the estimation performance under different approximation methods is simulated.The results show that the estimation performance of the 4-point linear fitting under the AWGN channel can exceed the linear interpolation,and as the number of fitting points increases,the estimation performance gets better and better.But the fitting method needs to judge the current channel statistical law,otherwise it can not select an effective fitting function.3.According to the algorithm proposed in the previous article,this paper designs the hardware implementation of cell search,and then implements the proposed algorithm on FPGA and applies it to the existing scheme.Use the locally generated 5G signal to simulate the code,and then use the actual 5G air interface signal to test the program on-chip.The test result shows that the cell search procedure implemented in this article can correctly synchronize with the 5G signal with a signal-to-noise ratio of-5d B.The maximum on-chip resource occupancy rate of the overall cell search program is 8.29%,leaving plenty of hardware space for the remaining channel processing modules.