Research On Channel Estimation And Channel Equalization Technique Of FBMC System

Using filter banks as modulators,Filter Bank Multicarrier(FBMC)gets higher spectral efficiency,smaller out-of-band emissions,better performance of Anti ICI and Anti ISI.However,the using of filter banks brings many problems to FBMC,such as higher implementation complexity,inherent signal interference,and the difficulty of signal demodulation.Channel estimation and equalization,as an important part of the receiver of the wireless communication system,affect the performance of the communication system.However,the filter bank cannot make the subcarriers strictly orthogonal,this introduces inherent interference between subcarriers.Interference increases the difficulty of signal demodulation.Traditional channel estimation and equalization techniques are unable to apply to FBMC systems.This paper focuses on the FBMC system,especially on the channel estimation and equalization technology and the corresponding pilot scheme for the FBMC system,introduces some methods of improving the accuracy of channel estimation in wireless channel environment and the transplantation of the classical equalization.This paper gives a Field Programmable Gate Array(FPGA)design of the methods.In this paper,two improved channel estimation algorithms are proposed for block pilots,including an improved algorithm based on block auxiliary pilots and an improved algorithm based on time filter.The improved block auxiliary pilot algorithm uses lower-energy pilot symbols,adds auxiliary pilot symbols on both sides of the pilot symbols to cancel out the inherent interference of the corresponding subcarriers.These auxiliary pilot symbols can also cancel out some of the inherent interference on adjacent subcarriers.The results show that the performance of this improved algorithm has a certain increase.The improved algorithm based on time filter improves spectrum efficiency by using two consecutive symbols to carry pilots and auxiliary pilots.The auxiliary pilots are used to cancel out the inherent interference of the corresponding subcarriers.A time filter is added to the channel estimation section of the receiver to adjust the channel estimation value.The results show that the proposed algorithm can get better performance and same transmission efficiency as the Orthogonal Frequency Division Multiplexing(OFDM)system.But this method increases the computational complexity.This paper selects the improved channel estimation algorithm based on time filter and zero-forcing equalization to realize on FPGA.This paper combines channel estimation and equalization to discuss,reduce parts of the calculation program,which reduces the resource consumption of FPGA.This paper gives the FPGA implementation block diagram of channel estimation and equalization.Through simulation,we can see that the designed FPGA project can complete the implementation of the algorithm.