Research And Design Of Interference Suppression Techniques In UFMC System

Universal Filtered Multi-Carrier(UFMC)has the advantages of high spectrum utilization and loose synchronization in the time domain,and has a great application prospect in packet transmission communication scenarios.At the same time,UFMC has been listed as a candidate waveform of 5G physical layer by the European Union.Therefore,the research of UFMC technology has aroused widespread concern in the academic community.Filtering each subband separately in the UFMC system results in non-orthogonality of the inter-subband carrier,which results in Interband Interference,IBI;at the same time,the time-varying wireless channel and Doppler effect make frequency offsets occur in the transmission signal,resulting in Inter Carrier Interference(ICI).Both ICI and IBI will reduce the transmission performance of the system.For this reason,this thesis conducts in-depth research on the elimination methods of ICI and IBI in UFMC system.The specific work is as follows:Firstly,based on the research of ICI self-cancellation(SC)algorithm in UFMC system,aiming at the low spectrum utilization of SC algorithm,this thesis proposes an optimized scheme combined raised cosine windowing and Partial Self Cancellation(PSC),which improves the spectrum utilization of the system by setting a fixed-proportional self-eliminating subcarrier within the subcarriers.Simulation results show that the optimization scheme proposed in this thesis has improved both transmission performance and spectrum utilization.Secondly,aiming at the limited performance of the Subcarrier Weighting(SW)interference suppression algorithm for improving the UFMC system,this thesis proposes an improved algorithm based on the algorithm combined with the Carrier Cancellation(CC)method.The newly inserted weighted sub-carriers between the sub-bands further suppress the out-of-band attenuation of the adjacent sub-bands.Simulation results show that the improved algorithm has lower BER and out-of-band attenuation.Finally,a feasible implementation scheme for the proposed SC and its improved interference suppression algorithm is designed on the Software Defined Radio platform to verify the reliability of the algorithm.Specifically,a UFMC baseband transmission system is built on the GNU Radio software and an interference suppression functionmodule is implemented.With existing UFMC receivers,the algorithm performance is verified through actual signal transmission.Experimental results show that the algorithm can improve the system's anti-jamming capability,and the measured results are basically consistent with the simulation results.