1,108 research outputs found
On Secrecy Performance of Antenna Selection Aided MIMO Systems Against Eavesdropping
In this paper, we consider a multiple-input multiple-output (MIMO) system
consisting of one source, one destination and one eavesdropper, where each node
is equipped with an arbitrary number of antennas. To improve the security of
source-destination transmissions, we investigate the antenna selection at the
source and propose the optimal antenna selection (OAS) and suboptimal antenna
selection (SAS) schemes, depending on whether the source node has the global
channel state information (CSI) of both the main link (from source to
destination) and wiretap link (from source to eavesdropper). Also, the
traditional space-time transmission (STT) is studied as a benchmark. We
evaluate the secrecy performance of STT, SAS, and OAS schemes in terms of the
probability of zero secrecy capacity. Furthermore, we examine the generalized
secrecy diversity of STT, SAS, and OAS schemes through an asymptotic analysis
of the probability of zero secrecy capacity, as the ratio between the average
gains of the main and wiretap channels tends to infinity. This is different
from the conventional secrecy diversity which assumes an infinite
signal-to-noise ratio (SNR) received at the destination under the condition
that the eavesdropper has a finite received SNR. It is shown that the
generalized secrecy diversity orders of STT, SAS, and OAS schemes are the
product of the number of antennas at source and destination. Additionally,
numerical results show that the proposed OAS scheme strictly outperforms both
the STT and SAS schemes in terms of the probability of zero secrecy capacity.Comment: 11 pages; IEEE Transactions on Vehicular Technology, 201
Buffer-Aided Relay Selection Algorithms for Physical-Layer Security in Wireless Networks
In this work, we consider the use of buffer-aided relays, linear precoding
techniques and multiple antennas for physical-layer security in wireless
networks. We develop relay selection algorithms to improve the secrecy-rate
performance of cooperative multi-user multiple-antenna wireless networks. In
particular, we propose a novel finite buffer-aided relay selection algorithm
that employs the maximum likelihood (ML) criterion to select sets of relays
which fully exploit the flexibility offered by relay nodes equipped with
buffers. Numerical results show the benefits of the proposed techniques as
compared to prior art.Comment: 5 pages, 3 figures in WSA 201
Large-Scale MIMO Relaying Techniques for Physical Layer Security: AF or DF?
In this paper, we consider a large scale multiple input multiple output
(LS-MIMO) relaying system, where an information source sends the message to its
intended destination aided by an LS-MIMO relay, while a passive eavesdropper
tries to intercept the information forwarded by the relay. The advantage of a
large scale antenna array is exploited to improve spectral efficiency and
enhance wireless security. In particular, the challenging issue incurred by
short-distance interception is well addressed. Under very practical
assumptions, i.e., no eavesdropper channel state information (CSI) and
imperfect legitimate CSI at the relay, this paper gives a thorough secrecy
performance analysis and comparison of two classic relaying techniques, i.e.,
amplify-and-forward (AF) and decode-and-forward (DF). Furthermore, asymptotical
analysis is carried out to provide clear insights on the secrecy performance
for such an LS-MIMO relaying system. We show that under large transmit powers,
AF is a better choice than DF from the perspectives of both secrecy performance
and implementation complexity, and prove that there exits an optimal transmit
power at medium regime that maximizes the secrecy outage capacity.Comment: arXiv admin note: text overlap with arXiv:1401.304
Multi-Antenna Relay Aided Wireless Physical Layer Security
With growing popularity of mobile Internet, providing secure wireless
services has become a critical issue. Physical layer security (PHY-security)
has been recognized as an effective means to enhance wireless security by
exploiting wireless medium characteristics, e.g., fading, noise, and
interference. A particularly interesting PHY-security technology is cooperative
relay due to the fact that it helps to provide distributed diversity and
shorten access distance. This article offers a tutorial on various
multi-antenna relaying technologies to improve security at physical layer. The
state of the art research results on multi-antenna relay aided PHY-security as
well as some secrecy performance optimization schemes are presented. In
particular, we focus on large-scale MIMO (LS-MIMO) relaying technology, which
is effective to tackle various challenging issues for implementing wireless
PHY-security, such as short-distance interception without eavesdropper channel
state information (CSI) and with imperfect legitimate CSI. Moreover, the future
directions are identified for further enhancement of secrecy performance.Comment: 17 pages, 4 figures, IEEE Communications Magazine, 201
Study of Relay Selection for Physical-Layer Security in Buffer-Aided Relay Networks Based on the Secrecy Rate Criterion
In this paper, we investigate an opportunistic relay and jammer scheme along
with relay selection algorithms based on the secrecy rate criterion in
multiple-input multiple-output buffer-aided down link relay networks, which
consist of one source, a number of relay nodes, legitimate users and
eavesdroppers, with the constraints of physical layer security. The
opportunistic relay and jammer scheme is employed to improve the transmission
rate and different relay selection policies are performed to achieve better
secrecy rate with the consideration of eavesdroppers. Among all the
investigated relay selection policies, a relay selection policy which is
developed to maximize the secrecy rate based on exhaustive searches outperforms
other relay selection policies in terms of secrecy rate. Based on the secrecy
rate criterion, we develop a relay selection algorithm without knowledge of the
channels of the eavesdroppers. We also devise a greedy search algorithm based
on the secrecy rate criterion to reduce the computational complexity of the
exhaustive search technique. Simulations show the superiority of the secrecy
rate criterion over competing approaches.Comment: 6 pages, 3 figure
Study of Opportunistic Cooperation Techniques using Jamming and Relays for Physical-Layer Security in Buffer-aided Relay Networks
In this paper, we investigate opportunistic relay and jammer cooperation
schemes in multiple-input multiple-output (MIMO) buffer-aided relay networks.
The network consists of one source, an arbitrary number of relay nodes,
legitimate users and eavesdroppers, with the constraints of physical layer
security. We propose an algorithm to select a set of relay nodes to enhance the
legitimate users' transmission and another set of relay nodes to perform
jamming of the eavesdroppers. With Inter-Relay interference (IRI) taken into
account, interference cancellation can be implemented to assist the
transmission of the legitimate users. Secondly, IRI can also be used to further
increase the level of harm of the jamming signal to the eavesdroppers. By
exploiting the fact that the jamming signal can be stored at the relay nodes,
we also propose a hybrid algorithm to set a signal-to-interference and noise
ratio (SINR) threshold at the node to determine the type of signal stored at
the relay node. With this separation, the signals with high SINR are delivered
to the users as conventional relay systems and the low SINR performance signals
are stored as potential jamming signals. Simulation results show that the
proposed techniques obtain a significant improvement in secrecy rate over
previously reported algorithms.Comment: 8 pages, 3 figure
Improving Physical-Layer Security in Wireless Communications Using Diversity Techniques
Due to the broadcast nature of radio propagation, the wireless transmission
can be readily overheard by unauthorized users for interception purposes and is
thus highly vulnerable to eavesdropping attacks. To this end, physical-layer
security is emerging as a promising paradigm to protect the wireless
communications against eavesdropping attacks by exploiting the physical
characteristics of wireless channels. This article is focused on the
investigation of diversity techniques to improve the physical-layer security,
differing from the conventional artificial noise generation and beamforming
techniques which typically consume additional power for generating artificial
noise and exhibit high implementation complexity for beamformer design. We
present several diversity approaches to improve the wireless physical-layer
security, including the multiple-input multiple-output (MIMO), multiuser
diversity, and cooperative diversity. To illustrate the security improvement
through diversity, we propose a case study of exploiting cooperative relays to
assist the signal transmission from source to destination while defending
against eavesdropping attacks. We evaluate the security performance of
cooperative relay transmission in Rayleigh fading environments in terms of
secrecy capacity and intercept probability. It is shown that as the number of
relays increases, the secrecy capacity and intercept probability of the
cooperative relay transmission both improve significantly, implying the
advantage of exploiting cooperative diversity to improve the physical-layer
security against eavesdropping attacks.Comment: IEEE Network Magazine, 201
Energy-Efficient Power Allocation for Secure Communications in Large-Scale MIMO Relaying Systems
In this paper, we address the problem of energy-efficient power allocation
for secure communications in an amplify-and-forward (AF) large-scale
multiple-input multiple-output (LS-MIMO) relaying system in presence of a
passive eavesdropper. The benefits of an AF LS-MIMO relay are exploited to
significantly improve the secrecy performance, especially the secrecy energy
efficiency (bit per Joule). We first analyze the impact of transmit power at
the relay on the secrecy outage capacity, and prove that the secrecy outage
capacity is a concave function of transmit power under very practical
assumptions, i.e. no eavesdropper channel state information (CSI) and imperfect
legitimate CSI. Then, we propose an energy-efficient power allocation scheme to
maximize the secrecy energy efficiency. Finally, simulation results validate
the advantage of the proposed energy-efficient scheme compared to the capacity
maximization scheme.Comment: 6 pages, 5 figure
Recent Advances in Cloud Radio Access Networks: System Architectures, Key Techniques, and Open Issues
As a promising paradigm to reduce both capital and operating expenditures,
the cloud radio access network (C-RAN) has been shown to provide high spectral
efficiency and energy efficiency. Motivated by its significant theoretical
performance gains and potential advantages, C-RANs have been advocated by both
the industry and research community. This paper comprehensively surveys the
recent advances of C-RANs, including system architectures, key techniques, and
open issues. The system architectures with different functional splits and the
corresponding characteristics are comprehensively summarized and discussed. The
state-of-the-art key techniques in C-RANs are classified as: the fronthaul
compression, large-scale collaborative processing, and channel estimation in
the physical layer; and the radio resource allocation and optimization in the
upper layer. Additionally, given the extensiveness of the research area, open
issues and challenges are presented to spur future investigations, in which the
involvement of edge cache, big data mining, social-aware device-to-device,
cognitive radio, software defined network, and physical layer security for
C-RANs are discussed, and the progress of testbed development and trial test
are introduced as well.Comment: 27 pages, 11 figure
On Secure Mixed RF-FSO Systems With TAS and Imperfect CSI
In this work, we analyze the secrecy outage performance of a dual-hop relay
system composed of multiple-input-multiple-output radio-frequency (RF) links
and a free-space optical (FSO) link while a multiple-antenna eavesdropper
wiretaps the confidential information by decoding the received signals from the
resource node. The channel state information (CSI) of the RF and FSO links is
considered to be outdated. We propose three transmit antenna selection (TAS)
schemes to enhance the secrecy performance of the considered systems. The
secrecy outage performance with different TAS schemes is analyzed and the
effects of misalignment and detection technology on the secrecy outage
performance of mixed systems are studied. We derive the closed-form expressions
for probability density function (PDF) and cumulative distribution function
(CDF) over M\'alaga channel with imperfect CSI. Then the closed-form
expressions for the CDF and PDF of the equivalent signal-to-noise ratio (SNR)
at the legitimate receiver over Nakagami- and M\'alaga channels are derived.
Furthermore, the lower bound of the secrecy outage probability (SOP) with
different TAS schemes are derived. Besides, the asymptotic results for SOP are
investigated by exploiting the unfolding of Meijer's -function when the
electrical SNR of FSO link approaches infinity. Finally, Monte-Carlo simulation
results are presented to testify the correctness of the proposed analysis. The
results illustrate that the outdated CSI shows a strong effect on the secrecy
outage performance. In addition, increasing the number of antennas at the
source cannot significantly enhance the secrecy performance of the considered
systems.Comment: 14 pages, to appear in the IEEE Transactions on Communication
- …