Channel Estimate And Equalization For OFDM/OQAM Systems

With the development of wireless communication technology,the requirements of transmission rate,communication quality and spectrum efficiency of the wireless communication system will be higher and higher.Because of the good performance such as high spectrum efficiency and anti multipath fading,Orthogonal Frequency Division Multiplexing(OFDM)technology has become the core technology in the downlink of 4G.However,in the case of high dynamic communication senario,Doppler frequency shift will be more serious,which will lead to a spectrum spreading of the received signal in the wireless communication system,which makes the system performance worse.Orthogonal frequency division multiplexing / quadrature amplitude modulation(OFDM/OQAM)system uses filter which has a good time-frequency focusing properties,so the system do also has a good anti frequency selective fading and time selective fading ability when there is not add the cyclic prefix.In this paper,the OFDM/OQAM system is the research object,improving the anti time-frequency selective fading performance of the communication system is the research target,moreover,put forward and demonstrate the filter waveform design,pilot design and channel estimation and equalization technology of OFDM/OQAM communication system as the research content,focuses on the following:Firstly,the principle of OFDM/OQAM communication system is learned,the mathematical model is constructed,the fast implementation algorithm and the pulse filter function of the system are emphatically analyzed,and the performance of the system with different filter in different environments also has been analyzed,in addition,it also studied the modeling and Simulation of time-frequency channel.Secondly,the pilot design technology of OFDM/OQAM communication system is studied,and the design method of interference cancellation is discussed.Thirdly,the channel estimation techniques of OFDM/OQAM communication system are studied.Several classical channel estimation methods are introduced,and the channel estimation methods based on interference cancellation and interference are commonly used in OFDM/OQAM.This paper puts forward an optimized LMMSE iterative channelestimation algorithm,and analyzes the performance of the system under different channel estimation methods.Finally,a brief introduction to the OFDM/OQAM channel equalization technology have been taken,and the simulation and analysis the system performance in different channels also have been done.