| With the continuous progress of intelligent unmanned cluster technology,UAVs with different appearance and different functions emerge in an endless stream.Nowadays,UAVs have been widely used in military operations,agriculture,urban management,geology,disaster relief and other fields.From the development process and trend,intelligent unmanned cluster technology is not a single technology,but a comprehensive application of unmanned control,group intelligence,artificial intelligence,wireless mobile network and other related technologies.Through deep integration of relevant technologies,unmanned platform will be constructed to make it have independent decision-making ability and widely applied to various fields,which will highlight great advantages will have a profound impact.Unmanned cluster relies on wireless network for communication,and the broadcast characteristics of wireless channel make information easily eavesdropped in the process of transmission.Especially in the military field,once the UAV Communication Network is eavesdropped or even attacked by the enemy,it will bring fatal impact and even determine the whole war situation.Therefore,the research on the communication security technology of UAV cluster network has great practical significance and practical value.Traditional high-layer security mechanisms rely on third-party key management centers for key distribution and are not suitable for real-world UAVs communication networks.The physical-layer key generation technology that has attracted widespread attention in recent years looks like a pretty good choice.From the perspective of information theory security,this paper studies the physical layer secret key generation technology and key agreement technology,proposes a secure communication method suitable for UAVs networks,and analyzes the communication performance of UAVs networks under a specific model.The main works of this paper are as follows:(1)The research background of the subject and the current research status at home and abroad are introduced.The value of UAVs in future wars and the security issues they face are summarized.The existing problems in the research of communication security of UAVs are analyzed.At the same time,the main content,research ideas and chapter arrangement of the paper are briefly introduced.(2)This article briefly introduces some concepts commonly used in information theory security theory,and then introduces the wiretapping channel model researched by Wyner and summarizes the research results on security capacity.Then we introduce our problem model,the UAV network wire-tap channel model,and analyze the ergodic secrecy capacity and outage probability of the UAV cooperative communication network in the case of obeying independent and non-uniformly distributed Rayleigh fading channels.(3)The physical layer key generation technology is applied to the UAV communication network,and some problems that may exist in the real scene are studied.Aiming at the problem of low key generation rate caused by slow channel changes under quasi-static channels,a point-to-point key generation method based on random signal transmission is proposed,which increases the amount of mutual information between legal UAVs and thus effectively improves the key generation rate;In view of the unsatisfactory channel conditions in some harsh environments,a key generation mechanism in non strict reciprocity channel is proposed,which is proved to be effective.(4)A new method for calculating the log-likelihood ratio(LLR)of key generation is proposed.This method is based on the one-bit quantization of the channel measurement value and the difference between the channel estimation values of the legitimate reciprocal nodes.The proposed method uses the Slepian-Wolf low-density parity check(LDPC)code to achieve the advantage extraction and information reconciliation.The MATLAB simulation results show that the proposed method has some advantages over the traditional physical layer key agreement method. |
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