Abstract In this work, the physical layer security performance of an underlay cognitive buffer‐aided relay network over the general Nakagami‐ m fading channel model is addressed, where a primary source communicates with a destination via a decode‐and‐forward relay node in the presence of an eavesdropper and a secondary communication system. The relay is equipped with a finite‐size storage equipment or buffer which can store the sequence of received data packets from source and forward it immediately or subsequently in an adequate time‐slot. In this way, the buffer relay enables to adopt a link selection scheme in order to detect the best available link, (i.e. the one with higher secrecy rate) among the available data at source or at the relay buffer. The closed‐form expression for the secrecy outage probability (SOP), which is a widely adopted performance metric in the considered scenario, is also derived. Numerical results confirm the accuracy of the derived closed‐form analytic expression for SOP and indicates the interaction between secrecy performance and the Nakagami channel parameter m . In particular, it is shown that the SOP experiences a significant drop as the Nakagami channel parameter increases for a predefined target secrecy rate.
Abstract In this work, the physical layer security performance of an underlay cognitive buffer‐aided relay network over the general Nakagami‐ m fading channel model is addressed, where a primary source communicates with a destination via a decode‐and‐forward relay node in the presence of an eavesdropper and a secondary communication system. The relay is equipped with a finite‐size storage equipment or buffer which can store the sequence of received data packets from source and forward it immediately or subsequently in an adequate time‐slot. In this way, the buffer relay enables to adopt a link selection scheme in order to detect the best available link, (i.e. the one with higher secrecy rate) among the available data at source or at the relay buffer. The closed‐form expression for the secrecy outage probability (SOP), which is a widely adopted performance metric in the considered scenario, is also derived. Numerical results confirm the accuracy of the derived closed‐form analytic expression for SOP and indicates the interaction between secrecy performance and the Nakagami channel parameter m . In particular, it is shown that the SOP experiences a significant drop as the Nakagami channel parameter increases for a predefined target secrecy rate.
The authors investigate the secrecy performance of a cooperative relaying network, wherein a fixed source communicates with a fixed destination via an amplify‐and‐forward mobile relay in the presence of a passive mobile eavesdropper. They assume that the source‐to‐relay channel and relay‐to‐destination channel experience Nakagami‐ m fading, whereas relay‐to‐eavesdropper link follows double Nakagami‐ m fading. Under such a mixed fading environment, they derive the novel tight closed‐form expressions for the secrecy outage probability (SOP), probability of non‐zero secrecy capacity, and intercept probability of the considered system. They also deduce the asymptotic secrecy outage and intercept probability expressions in the high signal‐to‐noise ratio regime to highlight the impact of fading parameters and channel conditions on the secrecy diversity order. It is shown that the system can achieve secrecy diversity order of min( ) in terms of SOP, and in terms of intercept probability, where and represent the fading severity parameters between source and relay and between relay and destination, respectively. They also formulate and investigate analytically two optimisation problems, namely, optimal relay location with fixed power allocation and optimal power allocation with fixed relay location, to minimise the system SOP. They verify analytical findings via numerical and simulation results.
In this paper, the physical layer security in cognitive radio networks (CRNs) is investigated. We consider an underlay relay assisted CRN consisting of multiple secondary sources, multiple-antenna destination, a single relay, and multiple eavesdroppers. The destination node performs the maximal-ratio combining under uncorrelated Rayleigh fading channels. In more details, we consider, a secondary source is randomly selected to transmit its data, and a jammer is chosen from the remaining source nodes to send a jamming signal to the eavesdroppers. The closed-form expression of the secrecy outage probability is derived, based on the statistical characteristics of the communication channels, under the primary user's quality of service constraint. The derived analysis gives deep insights into the impact of network parameters on the performance of on the secrecy outage performance. Analytic results are corroborated through Monte Carlo simulation.
Abstract In this paper, the secrecy outage probability (SOP) of an energy harvesting aided underlay single input multiple output cognitive radio network under the multiple eavesdroppers is investigated. It is assumed that all the channels within the network are subjected to Nakagami‐m distributions. In order to quantify the secrecy performance of the concerned network, two eavesdroppers' scenarios are considered and this includes: Colluding Eavesdropping and noncolluding Eavesdropping. Based on these, the SOP closed‐form expressions are derived for the network under the two scenarios. Our findings illustrate that the network under the noncolluding eavesdropping scenario achieve better secrecy outage performance compared with colluding eavesdropping mode. Furthermore, the impact of number of eavesdroppers Ne, the number of antennas equipped at eavesdroppers Ae as well as fading parameter of the wiretap channel me on the network secrecy outage performance are demonstrated. Finally, the accuracy of the derived expressions is validated through the Monte‐Carlo simulations.
Secure data transmission in future high-capacity high-coverage multi-tier hierarchical networks, for which cognitive radio(CR) has emerged as an essential recipe, is of utmost importance. This paper investigates the secrecy outage performance of selection combining(SC) in CR networks(CRNs) over Rayleigh fading channels. In a single-input multiple-output(SIMO) wiretap channel, a secondary user transmits confidential messages to another secondary user, which is equipped with( 1)B Bn n ≥ antennas. Meanwhile, a passive eavesdropper, which is equipped with( 1)E En n ≥ antennas, intends to overhear the messages. Both the legal receiver and the eavesdropper adopt SC scheme to process the received multiple signals. The secondary transmitter uses the underlay strategy to guarantee the quality of service of the primary user without spectrum sensing. Compared to the work proposed by Maged Elkashlan et al. in Ref. [1], we present an alternative method to derive the closed-form expression for the secrecy outage probability(SOP) and develop a simplified SOP when the maximal transmit power at the secondary user is sufficiently high. Our results reveal the impact of the primary network on the secondary network with a multi-antenna wiretap channel and simulations are conducted to validate the accuracy of our proposed analytical models.
In this paper, we study the physical layer security for underlay cognitive radio network in the presence of an eavesdropper that tries to intercept the secondary transmission. Specifically, a transmission at each hop uses a same frequency band of a primary user as long as the interference that caused by the secondary transmission at a primary receiver does not excess a maximum tolerable interference level. We investigate the secrecy outage probability (SOP) for a cognitive decode-and-forward (DF) relay network. Moreover, we drive a closed-form expression of the SOP of the considered system. Simulation results validate our theoretical results under three distinct cases as follows: the signal-to-noise ratio (SNR) of the main link between a secondary transmitter and a corresponding receiver is, respectively, smaller, equal to, or larger than the SNR of the eavesdropper link between the same secondary transmitter and the eavesdropper.
This paper investigates the secrecy performance of a single-input multiple-output (SIMO) based underlay cognitive radio networks. In particular, a single-antenna secondary transmitter transmits its secret message to a multi-antenna equipped secondary node in the presence of a multi-antenna equipped passive eavesdropper under a peak interference constraint at the single-antenna primary receiver. We proficiently derive the expressions for secrecy outage probability (SOP), intercept probability, and ergodic secrecy capacity (ESC) for the considered system over$\alpha -\mu fadingchannels.Further,wecarryouttheasymptoticanalysisofSOPandinterceptprobabilityundertwocasesofinterest;1)whentheaveragesignal−to−noiseratio(SNR)ofthemainlink,i.e.,betweenthesecondarysourceandsecondarydestination,goestoinfinitywithafixedaverageSNRofwiretaplinkbetweenthesecondarysourceandsecondaryeavesdropper,and2)whentheSNRsofboththemainandwiretaplinkstendtoinfinity.Wecaninferthatasecrecydiversityorderof\frac {\alpha _{D}N_{D}\mu _{D}}{2}canbeachievedundercase1,where\alpha _{D}and\mu _{D}arethemainlinkfadingparameters,andN_{D}$denotes the number of antennas at the destination. Whereas, under case 2, the system’s secrecy diversity order becomes zero. Moreover, we also present some interesting findings for the ESC when the interference constrained secondary transmitter power is considerably high. Further, we validate our analytical framework through extensive simulation and numerical results, and demonstrate the effects of system/channel parameters on the secrecy performance of the considered system. Our results reveal that the higher number of eavesdropper antennas can have a more deleterious impact on the system’s secrecy performance.