5,090 research outputs found
Physical Layer Security: Coalitional Games for Distributed Cooperation
Cooperation between wireless network nodes is a promising technique for
improving the physical layer security of wireless transmission, in terms of
secrecy capacity, in the presence of multiple eavesdroppers. While existing
physical layer security literature answered the question "what are the
link-level secrecy capacity gains from cooperation?", this paper attempts to
answer the question of "how to achieve those gains in a practical decentralized
wireless network and in the presence of a secrecy capacity cost for information
exchange?". For this purpose, we model the physical layer security cooperation
problem as a coalitional game with non-transferable utility and propose a
distributed algorithm for coalition formation. Through the proposed algorithm,
the wireless users can autonomously cooperate and self-organize into disjoint
independent coalitions, while maximizing their secrecy capacity taking into
account the security costs during information exchange. We analyze the
resulting coalitional structures, discuss their properties, and study how the
users can self-adapt the network topology to environmental changes such as
mobility. Simulation results show that the proposed algorithm allows the users
to cooperate and self-organize while improving the average secrecy capacity per
user up to 25.32% relative to the non-cooperative case.Comment: Best paper Award at Wiopt 200
Optimal Relay Selection for Physical-Layer Security in Cooperative Wireless Networks
In this paper, we explore the physical-layer security in cooperative wireless
networks with multiple relays where both amplify-and-forward (AF) and
decode-and-forward (DF) protocols are considered. We propose the AF and DF
based optimal relay selection (i.e., AFbORS and DFbORS) schemes to improve the
wireless security against eavesdropping attack. For the purpose of comparison,
we examine the traditional AFbORS and DFbORS schemes, denoted by T-AFbORS and
TDFbORS, respectively. We also investigate a so-called multiple relay combining
(MRC) framework and present the traditional AF and DF based MRC schemes, called
T-AFbMRC and TDFbMRC, where multiple relays participate in forwarding the
source signal to destination which then combines its received signals from the
multiple relays. We derive closed-form intercept probability expressions of the
proposed AFbORS and DFbORS (i.e., P-AFbORS and P-DFbORS) as well as the
T-AFbORS, TDFbORS, T-AFbMRC and T-DFbMRC schemes in the presence of
eavesdropping attack. We further conduct an asymptotic intercept probability
analysis to evaluate the diversity order performance of relay selection schemes
and show that no matter which relaying protocol is considered (i.e., AF and
DF), the traditional and proposed optimal relay selection approaches both
achieve the diversity order M where M represents the number of relays. In
addition, numerical results show that for both AF and DF protocols, the
intercept probability performance of proposed optimal relay selection is
strictly better than that of the traditional relay selection and multiple relay
combining methods.Comment: 13 page
Intercept Probability Analysis of Cooperative Wireless Networks with Best Relay Selection in the Presence of Eavesdropping Attack
Due to the broadcast nature of wireless medium, wireless communication is
extremely vulnerable to eavesdropping attack. Physical-layer security is
emerging as a new paradigm to prevent the eavesdropper from interception by
exploiting the physical characteristics of wireless channels, which has
recently attracted a lot of research attentions. In this paper, we consider the
physical-layer security in cooperative wireless networks with multiple
decode-and-forward (DF) relays and investigate the best relay selection in the
presence of eavesdropping attack. For the comparison purpose, we also examine
the conventional direct transmission without relay and traditional max-min
relay selection. We derive closed-form intercept probability expressions of the
direct transmission, traditional max-min relay selection, and proposed best
relay selection schemes in Rayleigh fading channels. Numerical results show
that the proposed best relay selection scheme strictly outperforms the
traditional direct transmission and max-min relay selection schemes in terms of
intercept probability. In addition, as the number of relays increases, the
intercept probabilities of both traditional max-min relay selection and
proposed best relay selection schemes decrease significantly, showing the
advantage of exploiting multiple relays against eavesdropping attack.Comment: 5 pages. arXiv admin note: substantial text overlap with
arXiv:1305.081
Cooperative Secure Transmission by Exploiting Social Ties in Random Networks
Social awareness and social ties are becoming increasingly popular with
emerging mobile and handheld devices. Social trust degree describing the
strength of the social ties has drawn lots of research interests in many fields
in wireless communications, such as resource sharing, cooperative communication
and so on. In this paper, we propose a hybrid cooperative beamforming and
jamming scheme to secure communication based on the social trust degree under a
stochastic geometry framework. The friendly nodes are categorized into relays
and jammers according to their locations and social trust degrees with the
source node. We aim to analyze the involved connection outage probability (COP)
and secrecy outage probability (SOP) of the performance in the networks. To
achieve this target, we propose a double Gamma ratio (DGR) approach through
Gamma approximation. Based on this, the COP and SOP are tractably obtained in
closed-form. We further consider the SOP in the presence of Poisson Point
Process (PPP) distributed eavesdroppers and derive an upper bound. The
simulation results verify our theoretical findings, and validate that the
social trust degree has dramatic influences on the security performance in the
networks.Comment: 30 pages, 11 figures, to be published in IEEE Transactions on
Communication
Secure Communication with a Wireless-Powered Friendly Jammer
In this paper, we propose to use a wireless-powered friendly jammer to enable
secure communication between a source node and destination node, in the
presence of an eavesdropper. We consider a two-phase communication protocol
with fixed-rate transmission. In the first phase, wireless power transfer is
conducted from the source to the jammer. In the second phase, the source
transmits the information-bearing signal under the protection of a jamming
signal sent by the jammer using the harvested energy in the first phase. We
analytically characterize the long-time behavior of the proposed protocol and
derive a closed-form expression for the throughput. We further optimize the
rate parameters for maximizing the throughput subject to a secrecy outage
probability constraint. Our analytical results show that the throughput
performance differs significantly between the single-antenna jammer case and
the multi-antenna jammer case. For instance, as the source transmit power
increases, the throughput quickly reaches an upper bound with single-antenna
jammer, while the throughput grows unbounded with multi-antenna jammer. Our
numerical results also validate the derived analytical results.Comment: accepted for publication in IEEE Transactions on Wireless
Communication
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