72 research outputs found
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
Low-resolution ADC receiver design, MIMO interference cancellation prototyping, and PHY secrecy analysis.
This dissertation studies three independent research topics in the general field of wireless communications. The first topic focuses on new receiver design with low-resolution analog-to-digital converters (ADC). In future massive multiple-input-multiple-output (MIMO) systems, multiple high-speed high-resolution ADCs will become a bottleneck for practical applications because of the hardware complexity and power consumption. One solution to this problem is to adopt low-cost low-precision ADCs instead. In Chapter II, MU-MIMO-OFDM systems only equipped with low-precision ADCs are considered. A new turbo receiver structure is proposed to improve the overall system performance. Meanwhile, ultra-low-cost communication devices can enable massive deployment of disposable wireless relays. In Chapter III, the feasibility of using a one-bit relay cluster to help a power-constrained transmitter for distant communication is investigated. Nonlinear estimators are applied to enable effective decoding. The second topic focuses prototyping and verification of a LTE and WiFi co-existence system, where the operation of LTE in unlicensed spectrum (LTE-U) is discussed. LTE-U extends the benefits of LTE and LTE Advanced to unlicensed spectrum, enabling mobile operators to offload data traffic onto unlicensed frequencies more efficiently and effectively. With LTE-U, operators can offer consumers a more robust and seamless mobile broadband experience with better coverage and higher download speeds. As the coexistence leads to considerable performance instability of both LTE and WiFi transmissions, the LTE and WiFi receivers with MIMO interference canceller are designed and prototyped to support the coexistence in Chapter IV. The third topic focuses on theoretical analysis of physical-layer secrecy with finite blocklength. Unlike upper layer security approaches, the physical-layer communication security can guarantee information-theoretic secrecy. Current studies on the physical-layer secrecy are all based on infinite blocklength. Nevertheless, these asymptotic studies are unrealistic and the finite blocklength effect is crucial for practical secrecy communication. In Chapter V, a practical analysis of secure lattice codes is provided
Robust Beamforming for Security in MIMO Wiretap Channels with Imperfect CSI
In this paper, we investigate methods for reducing the likelihood that a
message transmitted between two multiantenna nodes is intercepted by an
undetected eavesdropper. In particular, we focus on the judicious transmission
of artificial interference to mask the desired signal at the time it is
broadcast. Unlike previous work that assumes some prior knowledge of the
eavesdropper's channel and focuses on maximizing secrecy capacity, we consider
the case where no information regarding the eavesdropper is available, and we
use signal-to-interference-plus-noise-ratio (SINR) as our performance metric.
Specifically, we focus on the problem of maximizing the amount of power
available to broadcast a jamming signal intended to hide the desired signal
from a potential eavesdropper, while maintaining a prespecified SINR at the
desired receiver. The jamming signal is designed to be orthogonal to the
information signal when it reaches the desired receiver, assuming both the
receiver and the eavesdropper employ optimal beamformers and possess exact
channel state information (CSI). In practice, the assumption of perfect CSI at
the transmitter is often difficult to justify. Therefore, we also study the
resulting performance degradation due to the presence of imperfect CSI, and we
present robust beamforming schemes that recover a large fraction of the
performance in the perfect CSI case. Numerical simulations verify our
analytical performance predictions, and illustrate the benefit of the robust
beamforming schemes.Comment: 10 pages, 5 figures; to appear, IEEE Transactions on Signal
Processing, 201
An Overview of Physical Layer Security with Finite-Alphabet Signaling
Providing secure communications over the physical layer with the objective of
achieving perfect secrecy without requiring a secret key has been receiving
growing attention within the past decade. The vast majority of the existing
studies in the area of physical layer security focus exclusively on the
scenarios where the channel inputs are Gaussian distributed. However, in
practice, the signals employed for transmission are drawn from discrete signal
constellations such as phase shift keying and quadrature amplitude modulation.
Hence, understanding the impact of the finite-alphabet input constraints and
designing secure transmission schemes under this assumption is a mandatory step
towards a practical implementation of physical layer security. With this
motivation, this article reviews recent developments on physical layer security
with finite-alphabet inputs. We explore transmit signal design algorithms for
single-antenna as well as multi-antenna wiretap channels under different
assumptions on the channel state information at the transmitter. Moreover, we
present a review of the recent results on secure transmission with discrete
signaling for various scenarios including multi-carrier transmission systems,
broadcast channels with confidential messages, cognitive multiple access and
relay networks. Throughout the article, we stress the important behavioral
differences of discrete versus Gaussian inputs in the context of the physical
layer security. We also present an overview of practical code construction over
Gaussian and fading wiretap channels, and we discuss some open problems and
directions for future research.Comment: Submitted to IEEE Communications Surveys & Tutorials (1st Revision
The Effect of Eavesdropper's Statistics in Experimental Wireless Secret-Key Generation
This paper investigates the role of the eavesdropper's statistics in the
implementation of a practical secret-key generation system. We carefully
conduct the information-theoretic analysis of a secret-key generation system
from wireless channel gains measured with software-defined radios. In
particular, we show that it is inaccurate to assume that the eavesdropper gets
no information because of decorrelation with distance. We also provide a bound
for the achievable secret-key rate in the finite key-length regime that takes
into account the presence of correlated eavesdropper's observations. We
evaluate this bound with our experimental gain measurements to show that
operating with a finite number of samples incurs a loss in secret-key rate on
the order of 20%.Comment: Submitted to the IEEE Transactions on Information Forensics and
Securit
Secure Transmission Design With Feedback Compression for the Internet of Things
ARC Discovery Projects Grant DP150103905
Enhancing Secrecy with Multi-Antenna Transmission in Wireless Ad Hoc Networks
We study physical-layer security in wireless ad hoc networks and investigate
two types of multi-antenna transmission schemes for providing secrecy
enhancements. To establish secure transmission against malicious eavesdroppers,
we consider the generation of artificial noise with either sectoring or
beamforming. For both approaches, we provide a statistical characterization and
tradeoff analysis of the outage performance of the legitimate communication and
the eavesdropping links. We then investigate the networkwide secrecy throughput
performance of both schemes in terms of the secrecy transmission capacity, and
study the optimal power allocation between the information signal and the
artificial noise. Our analysis indicates that, under transmit power
optimization, the beamforming scheme outperforms the sectoring scheme, except
for the case where the number of transmit antennas are sufficiently large. Our
study also reveals some interesting differences between the optimal power
allocation for the sectoring and beamforming schemes.Comment: to appear in IEEE Transactions on Information Forensics and Securit
A Critical Review of Physical Layer Security in Wireless Networking
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
Quantized VCG Mechanisms for Polymatroid Environments
Many network resource allocation problems can be viewed as allocating a
divisible resource, where the allocations are constrained to lie in a
polymatroid. We consider market-based mechanisms for such problems. Though the
Vickrey-Clarke-Groves (VCG) mechanism can provide the efficient allocation with
strong incentive properties (namely dominant strategy incentive compatibility),
its well-known high communication requirements can prevent it from being used.
There have been a number of approaches for reducing the communication costs of
VCG by weakening its incentive properties. Here, instead we take a different
approach of reducing communication costs via quantization while maintaining
VCG's dominant strategy incentive properties. The cost for this approach is a
loss in efficiency which we characterize. We first consider quantizing the
resource allocations so that agents need only submit a finite number of bids
instead of full utility function. We subsequently consider quantizing the
agent's bids
Unconditionally Secure Authentication and Integrity Protection for the Galileo Open Service Signal
The operational GNSSs do not offer authentication and integrity protection for the Open Service (OS) signal/message. But it is urgently needed, since several attacks can threat the OS user. By this reason the Galileo GNSS is working on this issue. This thesis contributes at the problem by adopting an approach as generic as possible, which outlines a theoretical bound on the key size. Therefore, the focus is providing data and signal unconditionally secure authentication and integrity pro
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