As a complement to high-layer encryption techniques, physical layer security has been widely recognized as a promising way to enhance wireless security by exploiting the characteristics of wireless channels, including fading, noise, and interference. In order to enhance the received signal power at legitimate receivers and impair the received signal quality at eavesdroppers simultaneously, multiple-antenna techniques have been proposed for physical layer security to improve secrecy performance via exploiting spatial degrees of freedom. This paper provides a comprehensive survey on various multiple-antenna techniques in physical layer security, with an emphasis on transmit beamforming designs for multiple-antenna nodes. Specifically, we provide a detailed investigation on multiple-antenna techniques for guaranteeing secure communications in point-to-point systems, dual-hop relaying systems, multiuser systems, and heterogeneous networks. Finally, future research directions and challenges are identified.

A Survey on Multiple-Antenna Techniques for Physical Layer Security

Physical layer security (PLS) has been extensively explored as an alternative to conventional cryptographic schemes for securing wireless links. Many studies have shown that the cooperation between the legitimate nodes of a network can significantly enhance their secret communications performance, relative to the noncooperative case. Motivated by the importance of this class of PLS systems, this paper provides a comprehensive survey of the recent works on cooperative relaying and jamming techniques for securing wireless transmissions against eavesdropping nodes, which attempt to intercept the transmissions. First, it provides a in-depth overview of various secure relaying strategies and schemes. Next, a review of recently proposed solutions for cooperative jamming techniques is provided with an emphasis on power allocation and beamforming techniques. Then, the latest developments in hybrid techniques, which use both cooperative relaying and jamming, are elaborated. Finally, several key challenges in the domain of cooperative security are presented along with an extensive discussion on the applications of cooperative security in key enablers for 5G communications, such as nonorthogonal multiple access, device-to-device communications, and massive multiple-input multiple-output systems.

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A Comprehensive Survey on Cooperative Relaying and Jamming Strategies for Physical Layer Security

In the last decade, cognitive radio (CR) has emerged as a major next generation wireless networking technology, which is the most promising candidate solution to solve the spectrum scarcity and improve the spectrum utilization. However, there exist enormous challenges for the open and random access environment of CRNs, where the unlicensed secondary users (SUs) can use the channels that are not currently used by the licensed primary users (PUs) via spectrum-sensing technology. Because of this access method, some malicious users may access the cognitive network arbitrarily and launch some special attacks, such as primary user emulation attack, falsifying data or denial of service attack, which will cause serious damage to the cognitive radio network. In addition to the specific security threats of cognitive network, CRNs also face up to the conventional security threats, such as eavesdropping, tampering, imitation, forgery, and noncooperation etc‥ Hence, Cognitive radio networks have much more risks than traditional wireless networks with its special network model. In this paper, we considered the security threats from passive and active attacks. Firstly, the PHY layer security is presented in the view of passive attacks, and it is a compelling idea of using the physical properties of the radio channel to help provide secure wireless communications. Moreover, malicious user detection is introduced in the view of active attacks by means of the signal detection techniques to decrease the interference and the probabilities of false alarm and missed detection. Finally, we discuss the general countermeasures of security threats in three phases. In particular, we discuss the far reaching effect of defensive strategy against attacks in CRNs.

A survey of security issues in Cognitive Radio Networks

With the rapid development of functional requirements in the emerging Industry 4.0 era, modern industrial control systems (ICSs) are no longer isolated islands, making them more vulnerable to various cyberattack threats. Cyberattacks on ICSs may have disruptive consequences, such as significant social and economic losses. To proactively address the security issue of ICSs, this article presents a unified architectural approach from the perspectives of cyberthreats on ICSs, security-related ICS technologies, and methods for ICSs. It incorporates secure networks, secure control systems, secure physical processes, and their interactions seamlessly into a unified framework. To increase the resistance of ICSs against intrusions, the network security in our architectural approach is to secure the data in motion through the integration of secure network architecture, secure industrial network protocols, and secure end-to-end communications. The protection of control systems in our architectural approach is risk-based and hierarchical and encompasses prevention- and tolerance-centric defenses. It provides a layer-by-layer defense so that an acceptable level of cybersecurity risk is achieved and maintained. Aiming to maintain the stable operation of physical ICS processes, the secure control in our architectural approach implements a security process against process-aware attacks through a resilient safety control scheme. The global and systematic architectural approach presented in this article for the ICS cybersecurity will help facilitate the design and implementation of cyberattack-resilient ICSs in the networked world. For further development of ICS security technologies, emerging challenges are identified and discussed to motivate future research efforts.

A Unified Architectural Approach for Cyberattack-Resilient Industrial Control Systems

Cooperative spectrum sensing (CSS) is an effective approach to improve the detection performance in cognitive radio (CR) networks. The CSS process imposes some additional security threats to the CR networks. One of the common threats is primary user emulation attack (PUEA). In this particular type of attack, some malicious users try to imitate primary signal characteristics and defraud CR users to prevent them from accessing the idle frequency bands. Here, we propose a novel cooperative sensing scheme with attack-aware capability in the presence of a malicious PUEA. More precisely, the probabilities of the presence of a PUEA fake signal in both presence and absence of the licensed PU signal are estimated. Then, the obtained parameters are used to determine the optimal threshold that minimizes the total error probability. Simulation results are presented to indicate the performance improvement of the proposed method against PUEA compared with the conventional method.

Secure cooperative spectrum sensing under primary user emulation attack in cognitive radio networks: Attack-aware threshold selection approach

Security has played a major role in cognitive radio networks. Numerous researches have mainly focused on attacking detection based on source localization and detection probability. However, few of them took the penalty of attackers into consideration and neglected how to implement effective punitive measures against attackers. To address this issue, this article proposes a novel penalty mechanism based on cognitive trust value. The main feature of this mechanism has been realized by six functions: authentication, interactive, configuration, trust value collection, storage and update, and punishment. Data fusion center (FC) and cluster heads (CHs) have been put forward as a hierarchical architecture to manage trust value of cognitive users. Misbehaving users would be punished by FC by declining their trust value; thus, guaranteeing network security via distinguishing attack users is of great necessity. Simulation results verify the rationality and effectiveness of our proposed mechanism.

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Security management based on trust determination in cognitive radio networks

A round-robin transmission model is proposed for machine-type communication gateways (MTCGs) served by long-time evolution e-NodeBs (eNBs) The function of the MTCGs is to collect and buffer data from their subscribed MTC devices (MTCDs) until they are served by an eNB The service of each MTCG follows an independent and identically distributed G/G/1 queue model, which can be employed with any distribution according to the MTCD traffic characteristics The system performance is analysed based on queuing theory

Jianwu Li

Papers

A survey of security issues in Cognitive Radio Networks

Security management based on trust determination in cognitive radio networks

Round-robin access for G/G/1 queue modelling machine-type communication gateways in long-time evolution networks