Research On Technique Of Anti-Frequency-Offset-Interference For Zero-Tail DFT-Spread-OFDM

In order to meet the needs of the 5~thh generation of mobile communication(5G)for low latency,high reliability,and high number of connections scenarios,the zero tail Discrete Fourier Transform-spread-Orthogonal Frequency Division Multiplexing(ZT DFT-S-OFDM)technology is proposed as a new type of single-carrier system,and becomes the next one of the candidates for 5G.ZT DFT-S-OFDM retains the advantages of low Peak to Average Power Ratio(PAPR)from DFT-S-OFDM,and overcomes the shortcomings of high Out of band(OOB)from OFDM/DFT-S-OFDM,moreover,ZT DFT-S-OFDM can adaptively adjust the length of the guard interval according to the channel length to avoid throughput waste.However,ZT DFT-S-OFDM is more sensitive to carrier frequency offsets(CFO).In addition,its OOB is still high compared to other alternative waveforms.This paper focuses on these two problems mentioned above.Firstly,this paper studies the overall architecture of ZT DFT-S-OFDM.The principle and implementation of the key parts of the system,which are different from the DFT-S-OFDM system,are described in detail.And then ZT DFT-S-OPDM is compared with OFDM and DFT-S-OFDM,to verify the performance of ZT DFT-S-OFDM from the aspects of power spectral density,PAPR,and bit error rate.Secondly,aiming at the sensitivity of CFO in ZT DFT-S-OFDM,a CFO estimation algorithm based on channel is proposed.Because of the special structure of ZT DFT-S-OFDM system,it is impossible to use the frequency offset estimation algorithm that has been studied so far,so a joint estimation algorithm in time domain is proposed.The simulation results show that the proposed frequency offset estimation method can realize frequency offset estimation and compensation in Ped-A and Veh-A channels to ensure the reliability of communication links.Finally,aiming at the frequency offset sensitivity and high out-of-band leakage problem of ZT DFT-S-OFDM,a filtered ZT DFT-S-OFDM is proposed in this paper.Aiming at the problem that the PAPR of the system is increased due to the superposition of the filter tail,this paper proposes an improved scheme for the system's fraction,thus reducing the PAPR of the filtered ZT DFT-S-OFDM system.On this basis,the performance of the filtered ZT DFT-S-OFDM system is verified by power spectral density(PSD),PAPR,and simulation results of bit error rate at different frequency offsets.The experimental results show that the effect of frequency offset on the system can be effectively reduced in the AWGN channel or Ped-A and Veh-A channels while reducing the out-of-band leakage.