Physical layer security is an emerging technique for improving wireless communication security, which is widely regarded as a complement to cryptographic technologies. To design physical layer security techniques for ...Physical layer security is an emerging technique for improving wireless communication security, which is widely regarded as a complement to cryptographic technologies. To design physical layer security techniques for practical scenarios, uncertainty and imperfections in the channel knowledge need to be taken into account. This paper is a survey of recent research on physical layer security that considers imperfect channel state information （CSI） at communication nodes. We first give an overview of the main information-theoretic measures of secrecy performance with imperfect CSI. Then, we describe several signal processing enhancements in secure transmission designs. These enhancements include secure on-off transmission, beamforming with artificial noise, and secure communication assisted by relay nodes or in cognitive radio systems. Recent studies of physical layer security in large-scale decentralized wireless networks are also summarized. Finally, open problems for on-going and future research are discussed.展开更多
According to the National Airport standards,this article has looked over the height of 180000 buildings in the airfield control height region of Cencun Airport(about 123.6 sq.km)for thefirst time.In the paper,based on...According to the National Airport standards,this article has looked over the height of 180000 buildings in the airfield control height region of Cencun Airport(about 123.6 sq.km)for thefirst time.In the paper,based on the planning&approving data and ADS40 aerial survey data,GIS spatial analysis,ADS40 stereo-altimetry technology,field digital measurement and 2D/3D visualization are used synthetically to achieve the results above.Furthermore,the quantity and spatial distribution of over theoretical height buildings are clarified,which is significant to review the airfield height management and to guide the regulatory plan of Tianhe Intellectualized Business District.展开更多
文摘Physical layer security is an emerging technique for improving wireless communication security, which is widely regarded as a complement to cryptographic technologies. To design physical layer security techniques for practical scenarios, uncertainty and imperfections in the channel knowledge need to be taken into account. This paper is a survey of recent research on physical layer security that considers imperfect channel state information （CSI） at communication nodes. We first give an overview of the main information-theoretic measures of secrecy performance with imperfect CSI. Then, we describe several signal processing enhancements in secure transmission designs. These enhancements include secure on-off transmission, beamforming with artificial noise, and secure communication assisted by relay nodes or in cognitive radio systems. Recent studies of physical layer security in large-scale decentralized wireless networks are also summarized. Finally, open problems for on-going and future research are discussed.
文摘According to the National Airport standards,this article has looked over the height of 180000 buildings in the airfield control height region of Cencun Airport(about 123.6 sq.km)for thefirst time.In the paper,based on the planning&approving data and ADS40 aerial survey data,GIS spatial analysis,ADS40 stereo-altimetry technology,field digital measurement and 2D/3D visualization are used synthetically to achieve the results above.Furthermore,the quantity and spatial distribution of over theoretical height buildings are clarified,which is significant to review the airfield height management and to guide the regulatory plan of Tianhe Intellectualized Business District.
