Research On Universal-filtered Multicarrier For 5G Wireless Communication System

New mobile communication scenarios raise new design challenges for 5G wireless communication system,requiring a flexible air interface.Although OFDM can combat the interference caused by channels effectively,it has greate out-of-band power leakage(OOB),and requires additional guard bands to avoid ACI?long cyclic prefix,not fully utilizing spectrum.What's more,it is sensitive to ICI requiring strict time-frequency synchronization.Therefore,new 5G multicarriers have become a hot research topic.In this thesis,comparison between OFDM?UFMC?FBMC and GFDM on OOB?PAPR(peak-to-average ratio)and spectral efficiency was conducted firstly.Afterwards new channel estimation and equalization schemes was proposed.Finally,an UFMC-MIMO scheme based on CP-HC-UFMC was suggested.The specific work is as follows:Firstly,the mechanism of UFMC at both transmitter and receiver was analyzed in detail under the AWGN channel proving that it can demodulate correctly at receiver by 2N-FFT.In order to simplify the design of sub-band filter,a simple design method for UFMC system with the same subband size was introduced.Analysis of the influence of sub-band filters on UFMC carrier spectrum was given,obtaining a basic principle to guide the design of UFMC system parameters.Comparison of CFO's effects on OFDM and UFMC was made by simulation,results show that UFMC is always better than OFDM,this offers the possibility to reduce synchronization requirement,making UFMC more suitable for applications with relatively low synchronization requirements in 5G.Secondly,comparison of OOB,PAPR and spectral efficiency was made between UFMC?OFDM?FBMC and GFDM.FBMC and GFDM can reduce out-of-band power leakage and relax time-frequency synchronization requirements by using filters like UFMC.In terms of OOB,FBMC and GFDM have lower out-of-band power leakage due to the use of sub-carrier filters with longer length.FBMC?GFDM and UFMC all have slightly larger PAPR than OFDM due to the use of various filters;GFDM and FBMC are more suitable for the transmission of services with longer frame length in 5G,while UFMC is more suitable for the service with short frame length.Thirdly,in order to eliminate the interference caused by multipath channel,a new channel estimation scheme suitable for UFMC system was proposed.This scheme designed a special pilot with repetitive patterns for channel estimation with low complexity.What's more two new equalization algorithms were proposed to eliminate ISI?ICI and IBI caused by multipath channel,which were Zero-Forcing equalization algorithm based on interference cancellation and equalization algorithm based on Iterative Interference Cancellation.Both algorithms can further eliminate ICI and IBI on the basis of eliminating ISI.Simulation results show that the proposed channel estimation and equalization algorithm can effectively eliminate the ISI,ICI and IBI,making it possible for UFMC to be applied in actual system.Finally,the solution which can combine UFMC with MIMO was studied.In order to combine them,an UMFC-MIMO transmission scheme based on CP-HC-UFMC was proposed in this thesis.This scheme designed a new UFMC implementation method based on cyclic prefix.The receiver of this multicarrier system can complete channel equalization and demodulation only by N-point FFT transform.Theoretical analysis proves that this solution can seamlessly use the point-to-point mathematical model of MIMO system and make full use of existing MIMO technologies by simple modification.Simulation results show that this scheme not only retains the advantages of traditional UFMC technology,but also reduces the implementation complexity of UFMC.