Network security with encryption and decryption technology to complete the application layer, but this technology will bring computing resources and a waste of energy, particularly in these two resources are limited wireless communication system for this problem, we use a large-scale multi-antenna technology, using beamforming algorithm in power and spectrum limited conditions, to maximize the mutual information system security, the simulation results demonstrate the ability to secure transmission algorithms can effectively improve the system.
Network security with encryption and decryption technology to complete the application layer, but this technology will bring computing resources and a waste of energy, particularly in these two resources are limited wireless communication system for this problem, we use a large-scale multi-antenna technology, using beamforming algorithm in power and spectrum limited conditions, to maximize the mutual information system security, the simulation results demonstrate the ability to secure transmission algorithms can effectively improve the system.
Due to the characteristics of the broadcast function of the wireless communication network, the problem of information security has become very serious. And because the traditional upper-layer encryption technology is accompanied by the advancement of computer technology and eavesdropping technology, it has become more and more far from being able to meet the needs of modern society for information security. The multi-antenna beamforming technology in the airspace technology is a technology that can effectively increase the strength of the legal signal and suppress the eavesdropping signal. Therefore, it has become the most important technology in the physical layer security of our country and deserves our attention. Therefore, this article aims to study the wireless communication physical layer information security technology based on airspace technology. Based on the analysis of the basic theory of physical layer security, the current status of physical layer security research and the airspace physical layer security technology, the artificial noise auxiliary technology is promoted and applied to security identification. Taking the speed of maximizing the safe frequency spectrum as the design goal, an algorithm for joint optimization of information noise beam and artificial noise beam is proposed. The simulation results show that this algorithm can effectively improve the security and stability of the system, and it can also solve the eavesdropping problem.
With the rapid development of mobile Internet technology and the continuous improvement of people's understanding of data security, the research on the secure transmission of information in wireless communication systems has received extensive attention. Using physical layer security technology to protect the information transmission security is not only beneficial to prevent illegal eavesdroppers from obtaining the transmitted information, but also greatly reduces the computational complexity caused by traditional encryption methods. Based on Shannon's communication theory and Wyner's wiretapping channel, this paper briefly introduces the physical layer transmission security technologies such as beamforming, artificial noise and cooperative communication, mainly analyzes massive MIMO antennas and intelligent reflecting surface, and makes a prospect summary. At the end of the paper, the open issues are identified as our future research directions.
It is an important approach for achieving secure physical layer transmission using beamforming technology of multi-antenna, most of the transmission models are built on the perfect channel estimation model. The paper studies the secure physical layer transmission of multi-antenna beamforming with imperfect channel estimation information (CSI) and discusses the realization of the physical layer security in the actual communication environment with channel estimation error. We build a secure physical layer transmission model using beamforming technology of multi-antenna combined with SVD precoding technology, and we also prove the realization of the model with simulation under imperfect CSI.
This paper considers a basic MIMO information-energy broadcast system, where a multi-antenna transmitter transmits information and energy simultaneously to a multi-antenna information receiver and a dual-functional multi-antenna energy receiver which is also capable of decoding information. Due to the open nature of wireless medium and the dual purpose of information and energy transmission, secure information transmission while ensuring efficient energy harvesting is a critical issue for such a broadcast system. Providing that physical layer security techniques are adopted for secure transmission, we study beamforming design to maximize the achievable secrecy rate subject to a total power constraint and an energy harvesting constraint. First, based on semidefinite relaxation, we propose global optimal solutions to the secrecy rate maximization (SRM) problem in the single-stream case and a specific full-stream case. Then, we propose inexact block coordinate descent (IBCD) algorithm to tackle the SRM problem of general case with arbitrary number of streams. We prove that the IBCD algorithm can monotonically converge to a Karush-Kuhn-Tucker (KKT) solution to the SRM problem. Furthermore, we extend the IBCD algorithm to the joint beamforming and artificial noise design problem. Finally, simulations are performed to validate the effectiveness of the proposed beamforming algorithms.
Physical layer security is a promising technique for information security. In multi-antenna systems, secure transmission designs are of crucial importance for physical layer security. In this thesis, our research focuses on the secure transmission designs for jamming signal aided multi-antenna systems. We first investigate robust secure transmission designs for a cooperative jamming aided multiple-input-single-output (MISO) system. Two scenarios are considered: (a) eavesdroppers' channel state information (ECSI) is available and (b) ECSI is unavailable. In scenario (a), a quality-of-service (QoS)-based design is considered to minimize the worst case signal-to-interference-and-noise ratio at the eavesdroppers. A secrecy rate based design is also studied. In scenario (b), a QoS-based design is considered to maximize the power of jamming signals, and the secrecy rate based design is not applicable. We propose an algorithm for each design problem through semidefinite relaxation. Our analysis shows that, even though the beamforming scheme in our designs is fixed as single stream beamforming, this does not cause any loss of optimality. We further consider secure transmission designs for a simultaneous wireless information and power transfer enabled MISO heterogeneous cellular network. In the considered system, all base stations (BSs) send confidential messages to information receivers and energy signals to energy receivers (ERs). BSs collaboratively utilize the energy signals as jamming signals to cripple ERs' interceptions. We propose a sum logarithmic secrecy rate maximization design problem. To tackle the design problem, we propose a semidefinite relaxation and successive convex approximation based centralized secure transmission design algorithm. Moreover, an alternating direction method of multipliers based distributed secure transmission design is also proposed. Simulation results demonstrate the effectiveness of the proposed algorithms. Secure transmission is designed for a cooperative jamming aided MISO non-orthogonal multiple access system. We consider an outage constrained secure transmission design problem under the assumption that only statistical ECSI is available. In the design problem, the minimum probabilistic secrecy rate is maximized. Based on 0-norm and the path-following approach, we develop an algorithm to find a solution to the design problem. Simulation results demonstrate that the secrecy outage probability can be guaranteed through the proposed secure transmission design algorithm.
Wireless broadcast allows widespread and easy information transfer. However, it may expose the information to unintended receivers, which could include eavesdroppers. As a solution, cryptography at the higher network levels has been used to encrypt and protect data. Cryptography relies on the fact that the computational power of the adversary is not enough to break the encryption. However, due to increasing computing power, the adversary power also increases. To further strengthen the security and complement the encryption, the concept of physical layer security has been introduced and surged an enormous amount of research. Widely speaking, the research in physical layer security can be divided into two directions: the information-theoretic and signal processing paradigms. This thesis starts with an overview of the physical layer security literature and continues with the contributions which are divided into the two following parts. In the first part, we investigate the information-theoretic secrecy rate. In the first scenario, we study the confidentiality of a bidirectional satellite network consisting of two mobile users who exchange two messages via a multibeam satellite using the XOR network coding protocol. We maximize the sum secrecy rate by designing the optimal beamforming vector along with optimizing the return and forward link time allocation. In the second scenario, we study the effect of interference on the secrecy rate. We investigate the secrecy rate in a two-user interference network where one of the users, namely user 1, requires to establish a confidential connection. User 1 wants to prevent an unintended user of the network to decode its transmission. User 1 has to adjust its transmission power such that its secrecy rate is maximized while the quality of service at the destination of the other user, user 2, is satisfied. We obtain closed-form solutions for optimal joint power control. In the third scenario, we study secrecy rate over power ratio, namely ``secrecy energy efficiency''. We design the optimal beamformer for a multiple-input single-output system with and without considering the minimum required secrecy rate at the destination. In the second part, we follow the signal processing paradigm to improve the security. We employ the directional modulation concept to enhance the security of a multi-user multiple-input multiple-output communication system in the presence of a multi-antenna eavesdropper. Enhancing the security is accomplished by increasing the symbol error rate at the eavesdropper without the eavesdropper's CSI. We show that when the eavesdropper has less antennas than the users, regardless of the received signal SNR, it cannot recover any useful information; in addition, it has to go through extra noise enhancing processes to estimate the symbols when it has more antennas than the users. Finally, we summarize the conclusions and discuss the promising research directions in the physical layer security.