Parameter Estimation Of Signals And Application Of Wireless Security

For a long time,modulation recognition and parameter estimation of digital communication signals are hot topics in the field of communication,and play an important role in the traditional civil and military fields.With the rapid development of wireless technology,5G promotes the rise of the Internet of Things and other industries,resulting in more and more complex communication scenarios,such as Internet of Vehicles,smart city,home automation,etc.Signal parameter estimation technology may threaten its security as an attack means.Information security,as the basis and premise of communication,highlights the unprecedented importance.In this paper,modulation recognition,parameter estimation and vehicle radar safety are studied.The main work is as follows:In the channel environment of Gauss white noise,modulation recognition method based on high-order cumulant and cyclic spectrum is studied.The recognition objects are BPSK,QPSK,8PSK,OQPSK,UQPSK,MSK and so on.The basic principle of high-order cumulant method is introduced.The theoretical values of high-order cumulant of digital modulation signals are given.The recognition rate of each signal is obtained by simulation.Then this dissertation introduces the basic principle of the cyclic spectrum method,analyses the characteristics of the cyclic spectrum,simulates the cyclic spectrum and the fourth power spectrum of each digital signal,constructs the characteristic parameters according to the difference of the spectrum lines,and simulates and evaluates the recognition performance.A parameter estimation method of FMCW signal based on differential envelope detection is designed.Firstly,the signal is sampled and the differential operation is carried out to obtain the sequence with linear envelope change.Then,the envelope of the sequence is extracted by Hilbert transform.Finally,the envelope data is calculated to estimate the signal period,positive frequency,negative frequency,minimum and maximum frequency of sweep interval.The results show that this method can effectively estimate the parameters of FMCW signals under the conditions of no noise and high signal-to-noise ratio.A neutralizing deception attack method is designed for FMCW radar.Firstly,the FMCW radar attack model is given,and the three stages of the attack are described.Then,the received signals of vehicle radar before and after being attacked are expressed in frequency and time domain,and the expressions of neutralization signal and deception signal are deduced.In order to reduce the influence of parameter estimation error on neutralization effect,a phase difference compensation scheme is designed and simulated.Finally,a protective measure is designed for the designed FMCW signal parameter estimation method and neutralization deception attack method.The research shows that the neutralization deception attack against FMCW radar is theoretically feasible and will affect the safety of automobile radar and automobile.