Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey

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 introduced briefly. The survey concludes with observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials, 201

Wireless Throughput and Energy Efficiency under QoS Constraints

Mobile data traffic has experienced unprecedented growth recently and is predicted to grow even further over the coming years. As one of the main driving forces behind this growth, wireless transmission of multimedia content has significantly increased in volume and is expected to be the dominant traffic in data communications. Such wireless multimedia traffic requires certain quality-of-service (QoS) guarantees. With these motivations, in the first part of the thesis, throughput and energy efficiency in fading channels are studied in the presence of randomly arriving data and statistical queueing constraints. In particular, Markovian arrival models including discrete-time Markov, Markov fluid, and Markov-modulated Poisson sources are considered, and maximum average arrival rates in the presence of statistical queueing constraints are characterized. Furthermore, energy efficiency is analyzed by determining the minimum energy per bit and wideband slope in the low signal-to-noise ratio (SNR) regime. Following this analysis, energy-efficient power adaptation policies in fading channels are studied when data arrivals are modeled as Markovian processes and statistical QoS constraints are imposed. After formulating energy efficiency (EE) as maximum throughput normalized by the total power consumption, optimal power control policies that maximize EE are obtained for different source models. Next, throughput and energy efficiency of secure wireless transmission of delay sensitive data generated by random sources are investigated. A fading broadcast model in which the transmitter sends confidential and common messages to two receivers is considered. It is assumed that the common and confidential data, generated from Markovian sources, is stored in buffers prior to transmission, and the transmitter operates under constraints on buffer/delay violation probability. Under such statistical QoS constraints, the throughput is determined. In particular, secrecy capacity is used to describe the service rate of buffers containing confidential messages. Moreover, energy efficiency is studied in the low signal-to-noise (SNR) regime. In the final part of the thesis, throughput and energy efficiency are addressed considering the multiuser channel models. Five different channel models, namely, multiple access, broadcast, interference, relay and cognitive radio channels, are considered. In particular, throughput regions of multiple-access fading channels are characterized when multiple users, experiencing random data arrivals, transmit to a common receiver under statistical QoS constraints. Throughput regions of fading broadcast channels with random data arrivals in the presence of QoS requirements are studied when power control is employed at the transmitter. It is assumed that superposition coding with power control is performed at the transmitter with interference cancellation at the receivers. Optimal power control policies that maximize the weighted combination of the average arrival rates are investigated in the two-user case. Energy efficiency in two-user fading interference channels is studied when the transmitters are operating subject to QoS constraints. Specifically, energy efficiency is characterized by determining the corresponding minimum energy per bit requirements and wideband slope regions. Furthermore, transmission over a half-duplex relay channel with secrecy and QoS constraints is studied. Secrecy throughput is derived for the half duplex two-hop fading relay system operating in the presence of an eavesdropper. Fundamental limits on the energy efficiency of cognitive radio transmissions are analyzed in the presence of statistical quality of service (QoS) constraints. Minimum energy per bit and wideband slope expressions are obtained in order to identify the performance limits in terms of energy efficiency

A Stochastic based Physical Layer Security in Cognitive Radio Networks: Cognitive Relay to Fusion Center

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Cognitive radio networks (CRNs) are found to be, without difficulty wide-open to external malicious threats. Secure communication is an important prerequisite for forthcoming fifth-generation (5G) systems, and CRs are not exempt. A framework for developing the accomplishable benefits of physical layer security (PLS) in an amplify-andforward cooperative spectrum sensing (AF-CSS) in a cognitive radio network (CRN) using a stochastic geometry is proposed. In the CRN the spectrum sensing data from secondary users (SU) are collected by a fusion center (FC) with the assistance of access points (AP) as cognitive relays, and when malicious eavesdropping SU are listening. In this paper we focus on the secure transmission of active APs relaying their spectrum sensing data to the FC. Closed expressions for the average secrecy rate are presented. Analytical formulations and results substantiate our analysis and demonstrate that multiple antennas at the APs is capable of improving the security of an AF-CSSCRN. The obtained numerical results also show that increasing the number of FCs, leads to an increase in the secrecy rate between the AP and its correlated FC