Research On The Countermeasure Technology In OFDM With Narrowband Interference And Impulsive Noise

With the wide application of 4G communication technology and the rapid development of 5G communication technology,people have more and more requirements for the transmission performance of the modern digital communication systems.In the face of noise and interference,which limits the robustness,stability and reliability of communication system,the corresponding effective countermeasure technology is highly anticipated.Especially in the face of narrow-band interference(NBI)and impulse noise(IN)in the digital communication system,which is different from the white noise of Gauss but quit common existing,the traditional methods are rarely effective.Faced with this problem,this paper starts from the burst and sparsity of narrow-band interference and impulse noise.Based on the research of the characteristic expansion of the orthogonal frequency division multiplexing communication system(OFDM),several dimensions including the synchronization frame structure improvement,the time frequency interleaving with noise preprocessing and the stimulation and reconstruction of noise under the theory of compressed sensing are set out respectively to further enhance the performance of the orthogonal frequency division multiplexing communication system under the influence of narrow-band interference and impulse noise.After understanding the current research status of narrow-band interference and impulse noise resistance in the current orthogonal frequency division multiplexing communication systems,the characteristics of narrow-band interference and impulse noise are studied in this paper.Several typical narrow-band interference models and impulse noise modes are analyzed and simulated in detail.On this basis,The research is taken on the following aspects:First,in order to solve the problem that the synchronization performance and the carrier recovery of the orthogonal frequency division multiplexing system are easily affected by the narrow-band interference,the paper analyzes and improves on the traditional classical algorithm,and proposes an optimization algorithm using the scrambling operation and the preamble character,which improves the resistance of the orthogonal frequency division multiplexing system to the narrow-band interference.At the same time,the accuracy of timing synchronization and carrier frequency offset synchronization is enhanced.Second,considering about the drawback that conventional interleaving techniques cannot simultaneously mitigate narrow-band interference and impulse noise effectively,the optimal time-frequency combined interleaving technology is studied.At the same time,in order to make up for the poor performance of the time-frequency interleaving technique under the influence of strong narrow-band interference and impulse noise,the combined time-frequency interleaving scheme is proposed by the nonlinear noise preprocessing method with joint limiting,which effectively improves the resistance performance of the OFDM system to the poor channel with narrow-band interference and impulse noise coexistence.Finally,in view of the shortcomings of the traditional method of resisting impulse noise,such as poor precision,high complexity and low practicability,this paper proposes a reconstruction square method based on the compression perception theory and the sparse recovery theory,which is based on the prior information,and can effectively reconstruct the impulse noise,from which the impulse noise can be reconstructed effectively.It is beneficial to further eliminate noise and improve the performance of communication system.Through the above research,the paper aims at eliminating the main clue of the research by scrambling?diversity and restraining.The optimization design of anti narrow-band interference synchronization frame structure,the time frequency interleaving noise preprocessing method of narrowband interference and impulse noise,and the compression perceptual impulse noise reconstruction based on the prior information,which are beneficial to the further elimination of noise,are proposed for the narrow-band interference and impulse noise countermeasures in the OFDM system.Technological research provides theoretical basis and technological reserve.