Research On Anti-interference Transmission Technology In Wireless Networks

In order to meet people's demand for high communication quality and actively respond to the possible confrontational communication environment in the future,anti-interference waveform technology has been continuously developing and advancing.Traditional anti-interference technologies mainly include: spectrum spreading,adaptive antenna,error correction coding technology,and time domain,frequency domain,airspace interference suppression techniques.This thesis focuses on the research and design of anti-interference waveforms for spectrum extension and OFDM technology.Firstly,this thesis analyzes and summarizes the advantages and disadvantages of traditional anti-interference technology based on spread spectrum technology and OFDM technology and simulates their BER performance.Then,in view of the shortcomings of traditional OFDM anti-interference performance,this thesis proposes two improved Coded-OFDM based anti-interference waveform schemes.The simulation results show that the above two schemes can effectively improve the anti-interference ability of the system.For the single anti-interference type of single spread spectrum technology,the BER performance needs to be further improved.In this thesis,an improved anti-interference waveform scheme based on hybrid SS-OFDM is proposed.The simulation results show that the anti-interference system based on hybrid SS-OFDM can effectively improve the BER performance and resist multiple types of interference.Finally,the FrFT-based COFDM anti-interference system and the FrFT-based SS-OFDM anti-interference system are realized by replacing FFT and IFFT with FrFT and inverse FrFT.The above scheme is simulated by the Monte-Carlo method,and the comparison simulation results are observed.It is concluded that the FrFT-based COFDM anti-jamming system and the FrFT-based SS-OFDM anti-jamming system have good anti-interference performance.The FrFT method can effectively improve the system BER performance.Based on the traditional anti-jamming scheme,this thesis designs a variety of new anti-interference schemes,which improves the BER performance of the system and reduces the SNR threshold of system interruption.It can be widely used in communication scenarios with low SNR or strong interference.