Research On Channel Estimation Technology Of 60GHz Millimeter Wave Communication System

With the vigorous development of global mobile Internet and Internet of Things technologies,the number of mobile users and business traffic has exploded.How to meet the above-mentioned explosive growth of mobile communication service demands on limited spectrum resources has become a huge challenge facing the development of broadband wireless mobile communication system technology.It is no longer possible to allocate a wide continuous spectrum in the low frequency band,so the millimeter wave communication system technology that works in the frequency band above 60 GHz has attracted widespread attention.This article mainly studies the channel estimation technology of the millimeter wave communication system in the 60 GHz frequency band.First,this thesis introduces the development history and research status of millimeter wave communication technology,analyzes the main factors that affect the wireless propagation characteristics of millimeter wave frequency band electromagnetic waves in free space and atmospheric environment,and compares the characteristics and advantages of millimeter wave frequency band transmission.On the basis of introducing the development status of millimeter wave communication systems,this thesis analyzes the two wireless LAN standards of IEEE 802.11 ad and IEEE 802.11 ay in the 60 GHz frequency band,and studies the standard wireless frame structure and physical layer link parameters and other system frameworks.At the same time,this thesis outlines the channel model in typical application scenarios based on IEEE 802.15.3c.On this basis,this thesis gives an overall plan for a60 GHz millimeter wave communication system,defines the frame structure of the system,and designs a preamble based on Golay complementary sequence.Secondly,the key technology of channel estimation in wireless communication system is studied in this paper.On the basis of introducing channel estimation based on training sequence,blind channel estimation and semi-blind channel estimation technology,this thesis derives and analyzes least square channel estimation,minimum mean square error channel estimation,adaptive channel estimation and other channel estimation algorithms based on training sequence.At the same time,this thesis studies the classical interpolation algorithms such as linear interpolation,cubic spline interpolation and polynomial interpolation.In addition,this paper compares and analyzes the minimum mean square error and other performance of different algorithms through computer simulation.Then,the channel estimation algorithm based on Golay sequence is studied in this thesis.For single-point frequency domain equalization,the algorithm obtains the time-domain channel estimation by cross-correlation between the received signal and the local sequence,and then obtains the channel frequency response through signal processing.On this basis,two improved algorithms has been proposed.In the first algorithm,the system frame structure is changed,that is,the polarity structure of the Golay sequence is changed and a different channel estimation sequence length is selected.Algorithm 2 sets a threshold threshold,and sets the initial value of the time-domain channel estimation below the threshold to zero to suppress the influence of system noise.In addition,this thesis presents a joint phase noise processing channel estimation algorithm,which improves the channel estimation performance through iterative signal processing of channel estimation and phase noise suppression.This thesis verifies the minimum mean square error and bit error rate performance of different algorithms through computer simulation comparison,two of the improved algorithms and the channel estimation algorithm of joint phase noise processing have improved the minimum mean square error and bit error rate performance.Finally,the channel estimation technology based on matching pursuit is studied in this thesis.Aiming at the sparse characteristics of multipath channels in the millimeter wave frequency band,the channel estimation problem is transformed into a sparse signal reconstruction problem,and the idea of compressed sensing and matching tracking algorithms are used to solve the problem.This thesis analyzes and studies the matching pursuit algorithm and the orthogonal matching pursuit algorithm,gives the implementation steps of the orthogonal matching pursuit algorithm,and compares the minimum mean square error and bit error rate performance of different algorithms through computer simulation.Among them,the comprehensive performance of the orthogonal matching pursuit algorithm is better than other algorithms.