This paper provides a comprehensive review of the domain of physical layer security in multiuser wireless networks. The essential premise of physical layer security is to enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers, without relying on higher-layer encryption. This can be achieved primarily in two ways: without the need for a secret key by intelligently designing transmit coding strategies, or by exploiting the wireless communication medium to develop secret keys over public channels. The survey begins with an overview of the foundations dating back to the pioneering work of Shannon and Wyner on information-theoretic security. We then describe the evolution of secure transmission strategies from point-to-point channels to multiple-antenna systems, followed by generalizations to multiuser broadcast, multiple-access, interference, and relay networks. Secret-key generation and establishment protocols based on physical layer mechanisms are subsequently covered. Approaches for secrecy based on channel coding design are then examined, along with a description of inter-disciplinary approaches based on game theory and stochastic geometry. The associated problem of physical layer message authentication is also briefly introduced. The survey concludes with observations on potential research directions in this area.
This paper provides a comprehensive review of the domain of physical layer security in multiuser wireless networks. The essential premise of physical layer security is to enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers, without relying on higher-layer encryption. This can be achieved primarily in two ways: without the need for a secret key by intelligently designing transmit coding strategies, or by exploiting the wireless communication medium to develop secret keys over public channels. The survey begins with an overview of the foundations dating back to the pioneering work of Shannon and Wyner on information-theoretic security. We then describe the evolution of secure transmission strategies from point-to-point channels to multiple-antenna systems, followed by generalizations to multiuser broadcast, multiple-access, interference, and relay networks. Secret-key generation and establishment protocols based on physical layer mechanisms are subsequently covered. Approaches for secrecy based on channel coding design are then examined, along with a description of inter-disciplinary approaches based on game theory and stochastic geometry. The associated problem of physical layer message authentication is also briefly introduced. The survey concludes with observations on potential research directions in this area.
Due to the broadcast nature of wireless communications, it is difficult to shield transmitted signals from adversarial users in the coverage area of the transmission. This chapter highlights many issues concerned with achieving secrecy in the physical layer. It discusses overview of the foundations dating back to the pioneering key-based Shannon and keyless Wyner–Ziv works on information-theoretic security. In 1978, Leung-Yang-Cheong and Hellman considered the Gaussian wiretap channel. The chapter introduces multiformity of cooperative jamming techniques to show the effectiveness of jamming signals transmitted by some legitimate transmitters in a network of multiple transmitters and receivers in achieving physical layer security for a certain legitimate pair. It gives the idea of employing cooperative jammers in a multiple trusted/untrusted relay networks in order to improve security, and the interactions arising between cooperation and secrecy in the presence of untrusted relays are adopted. A resurgence of interest in aspects of secrecy at the physical layer has been experienced.
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.
Wireless networking has kept evolving with additional features and increasing capacity. Meanwhile, inherent characteristics of wireless networking make it more vulnerable than wired networks. In this thesis we present an extensive and comprehensive review of physical layer security in wireless networking. Different from cryptography, physical layer security, emerging from the information theoretic assessment of secrecy, could leverage the properties of wireless channel for security purpose, by either enabling secret communication without the need of keys, or facilitating the key agreement process. Hence we categorize existing literature into two main branches, namely keyless security and key-based security. We elaborate the evolution of this area from the early theoretic works on the wiretap channel, to its generalizations to more complicated scenarios including multiple-user, multiple-access and multiple-antenna systems, and introduce not only theoretical results but practical implementations. We critically and systematically examine the existing knowledge by analyzing the fundamental mechanics for each approach. Hence we are able to highlight advantages and limitations of proposed techniques, as well their interrelations, and bring insights into future developments of this area.
Physical layer security is emerging as a promising means of ensuring secrecy in wireless communications. The key idea is to exploit the characteristics of wireless channels such as fading or noise to transmit a message from the source to the intended receiver while keeping this message confidential from eavesdroppers. Topics covered in Trusted Communications with Physical Layer Security for 5G and Beyond include secrecy metrics for physical layer security over fading channels; trusted wireless communications with spatial multiplexing; directional modulation enabled physical layer wireless security; secure waveform for 5G systems; confidential and energy efficient communications using physical layer security; secure data networks with channel uncertainty; antenna selection strategies for wiretap channels; physical layer security for massive MIMO systems, millimeter wave cellular networks, non-orthogonal multiple access, multiuser relay networks, cognitive radio networks, MIMOME-OFDM systems; wirelessly powered communication systems and D2D-enabled cellular networks; and security solutions and applications at the physical layer, including case studies of secret key generation and secrecy coding in communication nodes and terminals.
The open nature of radio propagation enables ubiquitous wireless communication. This allows for seamless data transmission. However, unauthorized users may pose a threat to the security of the data being transmitted to authorized users. This gives rise to network vulnerabilities such as hacking, eavesdropping, and jamming of the transmitted information. Physical layer security (PLS) has been identified as one of the promising security approaches to safeguard the transmission from eavesdroppers in a wireless network. It is an alternative to the computationally demanding and complex cryptographic algorithms and techniques. PLS has continually received exponential research interest owing to the possibility of exploiting the characteristics of the wireless channel. One of the main characteristics includes the random nature of the transmission channel. The aforesaid nature makes it possible for confidential and authentic signal transmission between the sender and the receiver in the physical layer. We start by introducing the basic theories of PLS, including the wiretap channel, information-theoretic security, and a brief discussion of the cryptography security technique. Furthermore, an overview of multiple-input multiple-output (MIMO) communication is provided. The main focus of our review is based on the existing key-less PLS optimization techniques, their limitations, and challenges. The paper also looks into the promising key research areas in addressing these shortfalls. Lastly, a comprehensive overview of some of the recent PLS research in 5G and 6G technologies of wireless communication networks is provided.
This chapter provides a survey of physical layer security and key generation methods. This includes mainly an overview of ongoing research in physical layer security in the present and next generation communication networks. Although higher layer security mechanisms and protocols address wireless security challenges in large extent, more security vulnerabilities arise due to the increasingly pervasive existence of wireless communication devices. In this context, the focus of this chapter is mainly on physical layer security. Some security attacks in general are briefly reviewed. Models of physical layer security, information theoretic works, and key generation methods including quantization and reconciliation are discussed. Some latest developments for enhanced security like Multiple-Input Multiple-Output (MIMO) systems, reconfigurable antennas, and multiple relay systems are also presented. Finally, some existing and emerging application scenarios of physical layer security are discussed.