Research On Directional Modulation In Millimeter Wave Communication

Millimeter wave's wavelength belongs to the quantity level of millimeters and its frequency range from 30 GHz to 300 GHz.The bandwidth of Millimeter waves is very wide,so its transmission rates can reach to several Gbps.With the development of information technology and the popularity of mobile devices,the requirements for wireless communication transmission rates are getting higher and higher,however,in this case,millimeter-wave technology can meet the rate requirements.It is worthwhile to notice that if the eavesdropping receiver is sensitive enough,it still can obtain information from millimeter-wave sidelobe leakage.Therefore,there is a requirement for enhancing security in millimeter waves.The direction modulation can solve the security problem at the physical layer,so the direction modulation technology has attracted more and more attention in recent years.This thesis studied is focused on enhancing the safety level of millimeter waves with directional modulation techniques.This thesis is structured as follows:Firstly,briefly outlines the technologies of millimeter wave and the basic concepts of direction modulation.Secondly,the static system in millimeter wave direction modulation technology was studied.The traditional phased array directional modulation was studied.Based on phased array,a new high-order modulation direction modulation method was proposed.This method can achieve security without reducing the antenna gain and was verified with APSK.This thesis also studied several parameters of static direction modulation security,and provided a reference for the parameters selection of direction modulation system.Thirdly,the dynamic system in millimeter wave direction modulation technology was studied.The principle of dynamic direction modulation was studied and a dynamic phase modulation method based on phased array was proposed and the safety performance was analyzed.On this basis,in order to reduce the complexities,a low-complexity dynamic direction modulation implementation method which is the self-updating weight method was proposed.This method can not only reduce the complexity but also the resource space.Based on previous work,optimizing the weights of the solution to improve system security.Finally,the work of the thesis was summarized.The static direction modulation and dynamic direction modulation methods proposed in this thesis were evaluated.The system security can be effectively guaranteed.And the research direction of the subsequent direction modulation was prospected.