Research And Implementation Of Interference Suppression Algorithm In SC-FDE System

Wireless communication systems have been a hot research issue in recent years.Multipath transmission and channel multipath effects have brought a very serious impact on the reliability of wireless communication systems.The use of Single CarrierFrequency Domain Equalization(SC-FDE)technology in the system can not only cope with multipath fading in the propagation process,but also overcome Orthogonal Frequency Division Multiplexing(Orthogonal Frequency Division Multiplexing,OFDM)technology's inherent shortcomings such as poor anti-amplifier nonlinearity.Civil or military communications not only have natural interference,but there may also be manmade interference.Therefore,it is very necessary and very important to study antiinterference technology in communication systems to ensure the correct transmission of information.The frequency-domain interference suppression algorithms and timedomain interference suppression algorithms in the SC-FDE communication system are studied in this thesis,and the frequency-domain interference suppression and timedomain interference suppression are implemented in FPGA.Firstly,it is introduced the SC-FDE system structure and fading channel in this thesis,the method of modeling and simulating the fading channel in MATLAB are briefly explained,and the frequency domain single tone interference,frequency domain narrowband interference,and time domain pulse interference,the three mathematical models of interference are established.Secondly,the frequency domain interference suppression algorithm and the time domain interference suppression algorithm are studied in this thesis.Aiming at the two frequency-domain interferences,monophonic interference and narrow-band interference,the half overlap windowing method are studied in this thesis,an interference detection algorithm based on the Continuous Mean Excision(CME)method is designed,and the maximum likelihood Frequency domain interference suppression method is elaborated.The traditional interference clamping method is improved,and the interference suppression effect of the algorithm is improved by 4d B.The impact of different window functions,different interference signal ratios,and different threshold parameters on system performance under different channels are analyzed in the simulation.The interference suppression effects of different algorithms are compared in the simulation,and we can see the results that the half overlap windowing method has the best suppression effect.For the pulse time domain interference,the quenching method,the amplitude limiting method and the minimum mean square error time domain interference suppression method are studied in this thesis,and the large scale and samll scale timedomain interference suppression method are proposed,which can improve the adaptability of the time domain interference suppression method in hardware performance.The matrix interleaving is verified in the simulation that it can improve the ability of time-domain interference suppression.After comparing the performance of different time-domain interference suppression algorithms,it is found that the minimum mean square error time-domain interference suppression method and the large scale and small scale time-domain interference suppression method are both have good suppression effect.Finally,the half-overlap windowing method,the minimum mean square error timedomain interference suppression method and the large scale and samll scale time-domain interference suppression method are implemented in FPGA,and related modules in detail are introduced,hardware performances are analyzed.Using verilog language on Vivado and modelsim joint platform to do simulation and verification,and the half overlap windowing method and the minimum mean square error time-domain interference suppression method are tested on the FPGA based on the XC7K690 T chip,which verifies the correctness of its functions.