Research On Multi-carrier And UFMC Synchronization Technology For 5G

Multi-carrier technology is one of the research hotspots in 5G key technologies.UFMC has become a powerful candidate waveform because of its advantages of low out-of-band radiation and high frequency domain robustness.According to the related multi-carrier technology regulations in the 5G new air interface protocol,the OFDM technology adopted in the LTE downlink is difficult to continue to be applied because it is highly sensitive to synchronization deviation.Synchronization deviations severely impair system performance.Among them,the timing error leads to ISI,and the frequency error causes ICI.Therefore,how to overcome the interference caused by the synchronization error and meet the 5G communication requirements is a key problem that needs to be solved urgently.This article first introduces LTE's multi-carrier technology-OFDM.Based on this,it introduces several popular multi-carrier technologies in 5G,including FBMC,UFMC and GFDM.The basic principle is introduced,and summarized the advantages and disadvantages of each multi-carrier technology are compared and from the perspectives of technical specifications and application requirements supported by 5G.Among them,the UFMC system and OFDM system are mainly compared,and comparing with the different CFO or different TO,and when using different filter lengths,the performance demonstrated by the UFMC system is good or bad.This article focuses on the application of synchronization technology in UFMC systems.Firstly,the existing UFMC system synchronization technology is described by category.Based on the auxiliary frequency offset estimation algorithm,two improved schemes are proposed.Both schemes use the good characteristics of the ZC sequence.One of the CFO joint elimination schemes uses a delay correlation algorithm to obtain a coarse frequency offset estimate.Second,the residual frequency offset is obtained by using an M-segment autocorrelation operation.Another frequency offset elimination scheme is based on a LS criterion for channel estimation to achieve coarse frequency offset estimation and compensation,and a special training sequence is constructed to simplify the fine frequency offset estimation step.After theoretical derivation and simulation verification,the results proof that the improved frequency offset estimation scheme has better frequency offset compensation effect in multi-path fading channels and improves UFMC system performance.Based on the timing synchronization technology,refer to the commonly used timing algorithms in OFDM systems and analyze their applicability and estimated performance in UFMC.In order to solve the problem of low precision of traditional symbol timing synchronization algorithm in UFMC system,the existing symbol timing synchronization technology is optimized and a symbol timing scheme suitable for UFMC system is proposed.This scheme overcomes the problems of low synchronization applicability and high computational complexity of traditional algorithms.Finally,combining the frequency offset synchronization scheme and the timing synchronization scheme,a complete synchronization process is proposed.The Matlab simulation results show that the proposed scheme shows better synchronization performance in UFMC compared with the traditional synchronization scheme.