Research On Phase Noise Estimation And Compensation Algorithms For 5G Systems

With the continuous development of Internet technology,the existing network has been unable to meet the demand,and the Fifth Generation mobile communication system(5G)emerges as the times require.Compared with conventional mobile communication systems,5G supports higher carrier fr-equencies,which intensifies the effects of phase noise introduced by local oscillators.In this thesis,based on Phase Tacking Reference Signal(PT-RS),the phase noise elimination in Orthogonal Frequency Division Multiplexing(OFDM)system is studied.The influence of phase noise at the receiver of the OFDM system includes the Common Phase Error(CPE)and the Inter-Carrier-Interference(ICI).In this thesis,we study the phase difference estimation and compensation algorithms in two common OFDM systems.Meanwhile,the PT-RS parameters for practical applications are designed and given,and the improved phase difference estimation scheme is proposed.Furthermore,we propose an ICI estimation and elimination algorithm with high precision and low complexity.Through simulation,the performance of the algorithms under multiple PT-RS configuration modes and different channels is analyzed.The focus of phase difference estimation and compensation algorithm in Cyclic Prefix OFDM(CP-OFDM)system is how to eliminate the effects of frequency domain CPE.In this system,based on the analysis of the system model,the thesis firstly estimates and compensates the phase difference in frequency domain.Secondly,designs the time domain and frequency domain density of PT-RS,and the relevant recommendation forms are given.Finally,two improved schemes are proposed for the deficiencies of existing algorithms,and the comparison and analysis are carried out by simulation.The focus of the phase difference estimation and compensation algorithm in Discrete Fourier Transform Spread OFDM(DFT-S-OFDM)system is how to eliminate the effects of phase rotation on the time domain.Similarly,in this system,the thesis first analyzes the system model and realizes the estimation and compensation of the time domain phase difference.Secondly,the location of the PT-RS block,the PT-RS symbol-level time domain density and the sampling-level time domain density are designed,and relevant reference comments are given.Finally,according to the relevant simulation results,the difference of the influence of phase noise on the two OFDM systems and the difference between the corresponding phase difference estimation and compensation algorithm are analyzed.When the phase noise is large,the influence of ICI cannot be ignored.In order to reduce the complexity of the algorithm,this thesis only consider the interference from adjacent subcarriers.Firstly,in order to estimate ICI more accurately,based on the original single PT-RS structure,this thesis proposes two new PT-RS configuration modes,namely blank mode and dual PT-RS mode.Secondly,in the specific solution of ICI,this thesis proposes two solutions,which are independent solution and joint solution.Finally,matlab simulations are performed under Additive White Gaussian Noise(AWGN)channel and multipath fading channel.The results show that the accuracy of solving ICI jointly is higher than that of solving ICI independently,indicating that increasing the number of consolidations by using the potential relationship between ICI can effectively improve the accuracy of ICI estimation;In the blank mode,the system has the highest spectral efficiency,which indicates that although the data is effectively transmitted at the least,the ICI estimation accuracy is greatly improved,and finally the best spectral efficiency performance is obtained.