The Research Of ODFM Wireless Channel Estimation Model Based On Pilot

Orthogonal Frequency Division Multiplexing is one of the key technologies in the mobile communication technology,due to its unique characteristics such as fast transmission rate,high anti multipath fading ability and high spectrum utilization,it is regarded as the research focus of the communication in future by many experts and scholars.Channel estimation,as an important part of the OFDM technology,is to enable the receiver to recover the channel state information accurately,and to improve the performance of the system.The study of this paper mainly revolves around the OFDM wireless channel estimation based on pilot,the main research works are as follows:(1)The paper researches the characteristics of signal transmission in the wireless channel,the statistical features of multipath fading are introduced in detail,and the channel impulse response model has been given.By the researches of OFDM key technologies,focusing on its basic working principle,system structure model and its important component.The OFDM channel estimation based on pilot is studied in deeply,three pilot structures are analyzed: block type pilot,comb type pilot,and lattice type pilot,the paper focuses on four typical channel estimation algorithms about pilot: LS,MMSE,LMMSE and SVD-MMSE,and also introduces several common interpolation method in the subcarrier location.(2)The paper studies the traditional LMMSE algorithm in detail,because that it needs to deal with the complex matrix in the channel estimation,and the algorithm needs to predict the statistical features of the channel.In order to solve this problem,the paper introduces the weighted coefficient average method based on the sparse feature of the channel enery distribution,and introduces wavelet to deal with the symbol.Then,the paper gives the design of simulation experiment,the results of the simulation experimental show that the performance of the proved algorithm is better than the classic LS algorithm,the SVD-LMMSE algorithm,the LMMSE algorithm and the improved LMMSE algorithm by the weighted average method.(3)The paper researches the traditional SVD-LMMSE algorithm in deeply,although it has simplified the traditional LMMSE algorithm,there is a question of the big channel estimation error.Thus,the paper introduces the wavelet and the Empirical Mode Decomposition to solve this problem,and introduces the threshold to deal with the symbol.Then,the paper gives the design of simulation experiment,the results of simulation experimental show that the performance of the proved algorithm is better than the traditional LS algorithm,the LMMSE algorithm and the more popular SVD-LMMSE algorithm at present.