Research On Elimination Method Of Air Interface Waveform Non-Orthogonal Access Interference

In recent years,mobile communication technology has gradually entered the fifth generation mobile communication(5G).The newly defined application scenarios pose great challenges to the physical layer air interface waveforms,which need to be flexible and adaptable to meet the needs of multiple services.In the 5G air interface waveform design,each waveform configures parameters such as bandwidth,cyclic prefix,subcarrier interval,and transmission time interval for the physical frame structure according to the actual scenario.However,based on the complexity and variability of application scenarios,using a universal transmission waveform is hard to meet all communication requirements,which puts forward higher requirements for the coordination and cooperation of multiple waveforms.Non-orthogonal access of different waveforms or non-orthogonal access of the same waveform with different parameters will affect the transmission quality due to adjacent band interference.This thesis mainly studies the adjacent-band interference of non-orthogonal access of the air interface waveform.And this thesis is based on the research of orthogonal frequency division multiplexing(OFDM)and windowing orthogonal frequency division multiplexing(W-OFDM),which is one of the 5G candidate waveforms.The research content mainly divided into two aspects:1.This thesis proposes an adjacent-band interference elimination algorithm of threshold truncation and orthogonal matching pursuit recovery(TT-OMP-R),which sets a certain threshold to cut off the signal at the sending end,and selects the reliable observation vector that is less disturbed by noise at the receiving end,and finally uses orthogonal matching pursuit(OMP)to recover the truncated distorted signal.Through the analysis and simulation of OFDM and W-OFDM,it is verified that the TT-OMP-R algorithm can well deal with the adjacent band interference caused by the non-orthogonal access of arbitrary waveforms,and significantly reduces the bit error ratio of the system.2.Aiming at solving the problem of insufficient sparsity estimation in the OMP algorithm used in TT-OMP-R,this thesis analyzes the corresponding algorithm and selects the sparsity adaptive matching pursuit(SAMP)algorithm to improve TT-OMP-R,and puts forward an adjacent-band interference elimination optimization method of threshold truncation and sparsity adaptive matching pursuit recovery(TT-SAMP-R).Compared with TT-OMP-R,this scheme uses SAMP to recover the truncated distorted signal.Besides,through the analysis and simulation of OFDM and W-OFDM,it is verified that the proposed TT-SAMP-R algorithm can not only eliminate the adjacent band interference of the system in non-orthogonal access,but also improve the bit error ratio of the system compared with TT-OMP-R.