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.
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.
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 (Si)1≤2≤Nare taking turns in accessing the licensed spectrum of the primary users and communicating with a multi-antenna secondary base station (D) through the aid of a multi-antenna relay R in the presence of M eavesdroppers (Ek)1≤k≤Mthat 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 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.
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.
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.
This paper investigates the physical-layer security (PLS) of a single-input-multiple-output (SIMO) underlay cognitive radio network (CRN) over cascaded$\kappa −\mu fadingchannels.Asecondaryuser(SU)transmittercommunicateswithasecondaryuserreceiverovercascaded\kappa −\mu channels.Moreover,aneavesdropperresidingintheSUstransmission’srangewouldbecapableofinterceptingtheSUs’transmission.TheSUdestinationandtheeavesdropperarebothassumedtobeequippedwithmultipleantennas.Bothofthereceiversadoptmaximal−ratiocombining(MRC)overthemultiplecopiesofthesignal.InanunderlayCRN,theSUtransmittershouldkeepadjustingthetransmissionpowertoensurenottodisturbtheprimaryusers’(PUs)transmission.PLSisanalyzedintermsofthesecrecyoutageprobability(SOP)andtheprobabilityofnon−zerosecrecycapacity(P_{nz})$. Results indicate the evident effect of the cascade level and the number of antennas at the eavesdropper over the secrecy of the SUs pair. In addition, results reveal that PLS can be strengthened by increasing the number of antennas at the legitimate receiver. The impact of the interference level tolerable by the PU receiver over SUs’ secrecy is also analyzed. Monte-Carlo simulations and analytical results are presented to assess the system performance.
In this paper, the physical layer security of a multi-user jamming-assisted broadcast network in the presence of multiple eavesdroppers. Specifically, a base station (BS) is broadcasting data to multiple end-users via direct links in the presence of multiple passive wiretappers, while both the legitimate users and the eavesdroppers use a maximal-ratio combining scheme to achieve high spatial diversity gain. Furthermore, the BS is broadcasting a jamming signal that can not be canceled by the eavesdroppers to increase their decoding failure rates. All links are subject to Nakagami-m fading models. Relying on the upper incomplete moment-generating function of the combined Signal-to-interference-plus-noise ratio (SINR) at each wiretapper’s MRC output, tight approximate and asymptotic expressions for the secrecy outage probability (SOP) are derived considering two different scenarios, i.e., (i) absence and (ii) presence of the broadcasted artificial noise. The impact of the jamming signal level, severity fading parameter, and the number of MRC branches are examined, while the most influential parameter on the system’s security is retrieved. Numerical results and simulations reveal the accuracy of the obtained analytical expressions and gain more useful insights into the system’s secrecy.
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.