Narrowband Interference Compressed Detection And Mitigation In UWB System

Ultra-wideband(UWB)technology has the advantages of fast speed and low power consumption in short-distance wireless communication,and has broad application prospects in the field of wireless communication.However.due to the wide bandwidth of UWB signal,the high requirement of hardware resources in analog-to-digital conversion limits the rapid development of UWB technology.The compressed sensing theory has changed the current situation of high sampling rate of broadband signals and brought great convenience to the signal processing of UWB systems.On the other hand,as a method to improve the utilization of spectrum resources,UWB coexists with other systems in a low power way,which results in serious interference from other systems in the same frequency band.Therefore,narrowband interference(NBI)in the same frequency band must be detected and suppressed.In this thesis,the narrowband interference in UWB system is discussed based on compressed sensing.Two narrowband interference suppression methods are proposed from different ways:signal measurement stage and signal reconstruction stage.At the same time,an UWB digital receiver with narrowband interference suppression is designed.The main work of this thesis is described in the following two parts:1.Based on the application of compressed sensing theory in UWB system,the traditional GLRT detector is improved.The improved GLRT detector can suppress the interference signal in the measurement stage.Considering the spectrum leakage,the subspace of narrowband interference signal is obtained by the Consecutive Mean Excision algorithm(CME).Then,the orthogonal projection matrix of interference signal is constructed.and the measurement matrix is improved to further improve the GLRT detector.The simulation results show that the improved GLRT detector proposed in this paper not only has a good effect in acquiring the subspace of interference signal,but also can suppress the interference signal accurately,and improves the reliability of UWB system in the interference environment.2.To further improve the efficiency of UWB receiver,a narrowband interference suppression method based on parameter estimation is proposed.The method is based on the principle of selecting the atom with the greatest correlation in the reconstruction stage.First,the narrowband interference parameters are estimated,then the UWB signal parameters are estimated from the residual signal,then the interference suppression is realized from the signal reconstruction stage.At the same time,an UWB receiver with narrowband interference suppression is designed.The receiver can quickly complete symbol decision in the digital domain,which simplifies the design difficulty of the receiver.The simulation results show that the interference suppression method based on parameter estimation can achieve interference suppression and improve the performance of UWB receiver.