In limited space scenarios, the antennas in the multiantenna cognitive radio (CR) system are closely spaced and often experience correlation among them. In this work, the secrecy performance of correlated multiantenna CR receiver over Nakagami-m fading channels with imperfect channel state information is studied and analyzed. We consider the underlay CR paradigm wherein Alice in the secondary network communicates with Bob while Eve tries to overhear the communication. We also consider that the antennas at Bob and Eve are closely spaced and thus uniformly correlated. To this extent, we derive the analytical expressions for the first and second order secrecy measures like secrecy outage probability, average secrecy outage rate & average secrecy outage duration, respectively for the CR receiver. Moreover, in order to gain insights at high SNR, asymptotic analysis of secrecy outage probability is derived, thus obtaining the secrecy diversity gain of order LD(i.e., the number of antennas at Bob). Monte Carlo simulations are carried out to validate the proposed analytical framework.
In limited space scenarios, the antennas in the multiantenna cognitive radio (CR) system are closely spaced and often experience correlation among them. In this work, the secrecy performance of correlated multiantenna CR receiver over Nakagami-m fading channels with imperfect channel state information is studied and analyzed. We consider the underlay CR paradigm wherein Alice in the secondary network communicates with Bob while Eve tries to overhear the communication. We also consider that the antennas at Bob and Eve are closely spaced and thus uniformly correlated. To this extent, we derive the analytical expressions for the first and second order secrecy measures like secrecy outage probability, average secrecy outage rate & average secrecy outage duration, respectively for the CR receiver. Moreover, in order to gain insights at high SNR, asymptotic analysis of secrecy outage probability is derived, thus obtaining the secrecy diversity gain of order LD(i.e., the number of antennas at Bob). Monte Carlo simulations are carried out to validate the proposed analytical framework.
In this paper, the physical layer security of a dual-hop underlay uplink cognitive radio network is investigated over Nakagami-m fading channels. Specifically, multiple secondary sources are taking turns in accessing the licensed spectrum of the primary users and communicating with a multiantenna secondary base station D through the aid of a multiantenna relay R in the presence of M eavesdroppers that are also equipped with multiple antennas. Among the remaining nodes, one jammer is randomly selected to transmit an artificial noise to disrupt all the eavesdroppers that are attempting to intercept the communication of the legitimate links i.e., S-R and R-D. The received signals at each node are combined using maximal-ratio combining. Secrecy analysis is provided by deriving closed-form and asymptotic expressions for the secrecy outage probability. The impact of several key parameters on the system's secrecy e.g., transmit power of the sources, number of eavesdroppers, maximum tolerated interference power, and the number of diversity branches is investigated. Importantly, by considering two scenarios, namely (i) absence and (ii) presence of a friendly jammer, new insights are obtained for the considered communication system. Especially, we tend to answer to the following question: Can better secrecy be achieved without jamming by considering a single antenna at eavesdroppers and multiple-ones at the legitimate users (i.e., relay and end-user) rather than sending permanently an artificial noise and considering that both the relay and the destination are equipped with a single antenna, while multiple antennas are used by the eavesdroppers? The obtained results are corroborated through Monte Carlo simulation and show that the system's security can be enhanced by adjusting the aforementioned parameters.
I265 this paper, we investigate the secrecy performance of multi-input single-output and single-eavesdropper (MISOSE) cognitive radio (CR) networks over correlated fading channels. For the security enhancement, the transmit antenna selection (TAS) scheme is used to select the best transmit antenna at Alice based on the main channel. In order to analyze the impact of channel correlation coefficient, interference temperature threshold and antenna numbers on the secrecy performance, we firstly derive the exact closed-form expression of the secrecy outage probability (SOP) for the considered system taking into account the correlation between the main channel and wiretapping channel. Moreover, to extract more deep insights, the asymptotic expression of SOP in high main-to-eavesdropper ratio (MER) regime is also derived, which reveals that the channel correlation does not degrade the secrecy diversity order and even can strengthen the secrecy performance in high MER regime. Finally, numerical results are provided to demonstrate the correctness and accuracy of our analysis.
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.
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.
p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 9.0px Helvetica} span.s1 {font: 7.5px Helvetica} xAbstract—In this paper, the physical layer security of a dualhop underlay uplink cognitive radio network is investigated over Nakagami-m fading channels. Specifically, multiple secondary sources are taking turns in accessing the licensed spectrum of the primary users and communicating with a multiantenna secondary base station (D) through the aid of a multiantenna relay R in the presence of M eavesdroppers that are also equipped with multiple antennas. Among the remaining nodes, one jammer is randomly selected to transmit an artificial noise to disrupt all the eavesdroppers that are attempting to intercept the communication of the legitimate links i.e., Si -R and R-D. The received signals at each node are combined using maximum-ratio combining. Secrecy analysis is provided by deriving closed-form and asymptotic expressions for the secrecy outage probability. The impact of several key parameters on the system’s secrecy e.g., transmit power of the sources, number of eavesdroppers, maximum tolerated interference power, and the number of diversity branches is investigated. Importantly, by considering two scenarios, namely (i) absence and (ii) presence of a friendly jammer, new insights are obtained for the considered communication system. Especially, we tend to answer to the following question: Can better secrecy be achieved without jamming by considering a single antenna at eavesdroppers and multiple-ones at the legitimate users (i.e., relay and enduser) rather than sending permanently an artificial noise and considering that both the relay and the destination are equipped with a single antenna, while multiple antennas are used by the eavesdroppers? The obtained results are corroborated through Monte Carlo simulation and show that the system’s security can be enhanced by adjusting the aforementioned parameters.
This work explores the physical layer security of an underlay cognitive radio network (CRN) in the presence of a powerful interferer called a primary transmitter (PT) under peak interference power constraint. Under this scenario, the secondary transmitter (Alice) transmits secret information on a single antenna with the highest signal-to-interference plus noise ratio (SINR) to a legitimate receiver (Bob), and an eavesdropper (Eve) attempts to intercept that information. Depending upon the availability of channel state information (CSI) of the eavesdropper channel, we investigate the secrecy performance of the proposed network in the Rayleigh fading environment for both passive and active eavesdropping scenarios. We obtain analytical expressions for the secrecy outage probability, intercept probability, andϵ-outage secrecy capacity in a passive eavesdropping scenario. A complete investigation of the average secrecy capacity (ASC) has been made, and novel expressions for the exact and asymptotic ASC have been obtained for active eavesdropping. Bolstering these results, we also define a high SINR power offset, which quantifies the significance of main system parameters on the ASC explicitly. Further, the effect of outdated CSI of Alice to primary receiver link on the various performance metrics with the concept of interference-outage is also studied.