Design And Implementation Of A Low-Detection Interference-resistant Ad-hoc Network Waveform

Ad-hoc network communication system is a special network structure.In Ad-hoc network system,the point that differs from the traditional network structure is that each of them has the function of both router and host.Because of this characteristic And because of these excellent characteristics,self-organizing network technology performs well in harsh environments,IOT,and especially military scenarios.In order to meet the needs of military Ad-hoc networks,it is necessary to design reasonable waveforms and adopt suitable technical regimes to support them.Therefore,this paper will design a waveform regime that can be applied to Ad-hoc networks so that the communication has good low-detection,interferenceresistant,and highly dynamic characteristics.The main research of this paper is as follows.1.In order to achieve the requirement of low detection and interference immunity,a spread spectrum communication system is introduced in the waveform design.In the system of spread spectrum communication,direct sequence spread spectrum and frequency hopping spread spectrum are the two more common systems.In this paper,the two spread spectrum means and their fusion of the hybrid spread spectrum technology are studied.2.A major focus of the spread spectrum technology is the synchronization technology.In synchronization,it is necessary to ensure the consistency of the three parts of the signal:time,frequency,and frequency hopping frequency point.At the same time,in the frequency hopping system,the capture and tracking of the hopping pattern also have higher requirements.Therefore,in the hybrid spread spectrum system,more effective synchronization techniques are needed to achieve the consistency between the receiver and the sender and to guarantee the stability of the communication.In this paper,the synchronization techniques of direct sequence spread spectrum and frequency hopping are investigated separately,and an improved frequency hopping capture and PMF-FFT direct spread capture scheme is proposed,which effectively improves the resistance to high dynamic environment and combines them into a hybrid spread spectrum synchronization capture scheme.3.In military Ad-hoc networks,data chain is a common application scenario.In this application scenario,the motion of both transceiver and transmitter usually causes Doppler shift,which affects the frequency synchronization of spread spectrum synchronization at the same time,and also affects the sampling point at the receiver side,plus the deviation of the device caused by the crystal,etc.Therefore,the design of sampling point timing synchronization should be considered in the waveform design.In this thesis,the bit synchronization method in communication system is studied and an improved Gardner timing synchronization algorithm is proposed,which can effectively reduce timing jitter and make it perform better under interference.4.Select a suitable hardware platform,implement the designed physical layer waveform scheme on this hardware platform,and test the effect of this waveform under the upper layer Ad-hoc network application.