Secure Outage Probability Research Articles

Cooperative Hybrid Nonorthogonal Multiple Access-Based Mobile-Edge Computing in Cognitive Radio Networks

In order to efficiently compute the primary data and support the secondary quality-of-service (QoS) requirement, we propose a cooperative hybrid non-orthogonal multiple access (NOMA) scheme for mobile edge computing (MEC) assisted cognitive radio networks. In the proposed scheme, the primary computation task is securely offloaded to the secondary base station, and the hybrid NOMA technique is adopted to provide secondary spectrum access and secure the primary offloading simultaneously. The weighted energy consumption minimization problem for both the primary and secondary systems is first studied under the constraints of the primary system’s secure outage probability and the secondary system’s QoS requirements, and a two-stage algorithm is proposed to derive the optimal power, time slot and computation task allocation. To motivate the secondary system’s cooperation, we optimally allocate the transmit power, time slot and computation task, such that the average secondary system’s rate is maximized under the primary system’s security requirement, and we derive closed-form expressions for the optimal resource allocations. Numerical results demonstrate the performance superiority of the proposed scheme compared with the full-offloading scheme in terms of the energy consumption and the average secondary rate.

Enhancing Secrecy Performance of Cooperative NOMA-Based IoT Networks via Multiantenna-Aided Artificial Noise

With the increasing demand for security in many sectors, such as defense and health systems, developing secure Internet of Things (IoT) networks is a matter of great urgency. Looking at a potential solution for secure IoT systems, we investigate the physical layer security of cooperative nonorthogonal multiple access (NOMA) systems. After decoding information signal, the idea that a strong IoT node can serve as a relay node for other weak IoT nodes in enhancing their signal reception reliability, is known as cooperative NOMA. We consider both single-antenna and multiantenna aided transmission scenarios, where the base station (BS) communicates with two IoT nodes of different strengths. In the multiantenna scenario, artificial noise (AN) is generated at the BS and the strong IoT node for improving the security of the system. In order to characterize the secrecy performance, we derive new exact expressions of the security outage probability for both the IoT nodes under both the single-antenna and multiantenna aided scenarios. For the single-antenna scenario, we show that the power optimization at the BS and the strong IoT node can enhance the secrecy performance to some extent. For this case, we further study the secrecy diversity order of the overall system, which is mainly determined by the IoT node with the worse channel condition. For the multiantenna scenario, we derive the asymptotic secrecy outage probability (SOP) when the number of antennas tends to infinity. Extensive simulations have been conducted to verify the accuracy and effectiveness of the proposed analytical derivations. The presented results verify that the security performance of the cooperative NOMA-based IoT network can be improved through an appropriate power control scheme and by generating AN at the BS and the strong IoT node. The simulation results further illustrate that the asymptotic SOP is close to the exact one.

Enhancement of Multicast Security with Opportunistic Relaying Technique over <i>κ</i>-<i>μ</i> Shadowed Fading Channels

The effects of scatterers, fluctuation parameter and propagation clusters significantly affect the performance of κ-μ shadowed fading channel. On the other hand, opportunistic relaying is an efficient technique to improve the performance of fading channels reducing the effects of aforementioned parameters. Motivated by these issues, in this paper, a secure wireless multicasting scenario through κ-μ shadowed fading channel is considered in the presence of multiple eavesdroppers with opportunistic relaying. The main purpose of this paper is to ensure the security level in wireless multicasting compensating the loss of security due to the effects of power ratio between dominant and scattered waves, fluctuation parameter, and the number of propagation clusters, multicast users and eavesdroppers, by opportunistic relaying technique. The closed-form analytical expressions are derived for the probability of non-zero secrecy multicast capacity (PNSMC) and the secure outage probability for multicasting (SOPM) to understand the insight of the effects of above parameters. The results show that the loss of security in multicasting through κ-μ shadowed fading channel can be significantly enhanced using opportunistic relaying technique by compensating the effects of scatterers, fluctuation parameter, and the number of propagation clusters, multicast users and eavesdroppers.

Security in Multicast Over <i>α</i>-<i>μ</i> Fading Channels with Orthogonal Frequency Division Multiplexing

The orthogonal space-frequency block coding (OSFBC) with orthogonal frequency division multiplexing (OFDM) system reduces complexity in the receiver which improves the system performance significantly. Motivated by these advantages of OSFBC-OFDM system, this paper considers a secure wireless multicasting scenario through multiple-input multiple-output (MIMO) OFDM system employing OSFBC over frequency selective α-μ fading channels. The authors are interested to protect the desired signals from eavesdropping considering the impact of the number of multicast users and eavesdroppers, and the fading parameters α and μ. A mathematical model has been developed based on the closed-form analytical expressions of the probability of non-zero secrecy multicast capacity (PNSMC) and the secure outage probability for multi-casting (SOPM) to ensure the security in the presence of multiple eaves-droppers. The results show that the security in MIMO OSFBC OFDM system over α-μ fading is more sensitive to the magnitude of α and μ and this effect increases in the high signal-to-noise ratio (SNR) region of the main channel.

Enhancing Security in Multicellular Multicast Channels Reducing Interference Power with the Best Relay Selection

The capacity of wireless networks is fundamentally limited by interference. A few research has focused on the study of the simultaneous effect of interference and correlation, and less attention has been paid to the topic of canceling simultaneous effect of interference and correlation until recently. This paper considers a secure wireless multicasting scenario through multicellular networks over spatially correlated Nakagami-m fading channel in the presence of multiple eavesdroppers. Authors are interested to protect the desired signals from eavesdropping considering the impact of perfect channel estimation (PCE) with interference and correlation. The protection of eavesdropping is also made strong reducing the simultaneous impact of interference and correlation on the secrecy multicast capacity employing opportunistic relaying technique. In terms of the signal-to-interference plus noise ratio (SINR), fading parameter, correlation coefficient, the number of multicast users and eavesdroppers and the number of antennas at the multicast users and eavesdroppers, the closed-form analytical expressions are derived for the probability of non-zero secrecy multicast capacity and the secure outage probability for multicasting to understand the insight of the effects of aforementioned parameters. The results show that the simultaneous effects of correlation and interference at the multicast users degrade security in multicasting. Moreover, the security in multicasting degrades with the intensity of fading and the number of multicast users, eavesdroppers and antennas at the eavesdroppers. The effects of these parameters on the security in multicasting can be significantly reduced by using opportunistic relaying technique with PCE. Finally, the analytical results are verified via Monte-Carlo simulation to justify the validity of derived closed-form analytical expressions.

Secrecy Outage Performance of FD-NOMA Relay System With Multiple Non-Colluding Eavesdroppers

In this paper, we investigate the secrecy performance of a full-duplex (FD) non-orthogonal multiple access (NOMA) relay system under the presence of multiple non-colluding eavesdroppers over Rayleigh fading channels. Furthermore, to improve legitimate link's capacity, the partial relay selection (PRS) scheme is applied to choose the best relay. To evaluate the secrecy performance, we derive the closed-form expressions of the secure outage probability (SOP) of each user, the overall SOP and the sum effective secrecy throughput (EST) of the considered FD-NOMA relay system. We compare the SOP of the FD-NOMA relay system with that of the half-duplex (HD)-NOMA system and the SOPs of FD-NOMA relay system in the cases that PRS and multiple-relay (MR) schemes are employed at multiple relays. Monte-Carlo simulations verify the correctness of all derived mathematical expressions. Numerical results show that thanks to utilizing FD relays and PRS scheme, the considered FD-NOMA relay system has superior secrecy performance than other systems. Furthermore, increasing the number of FD relays, enhancing their self-interference cancellation capability, and selecting a suitable transmission power help to reduce the SOP of the considered FD-NOMA relay system. Meanwhile, the EST rapidly increases with the equivocation rate of the eavesdropping channel then gradually reaches the saturated maximum value.

Exact secure outage probability performance of uplinkdownlink multiple access network under imperfect CSI

In this paper, we study uplink-downlink non-orthogonal multiple access (NOMA) systems by considering the secure performance at the physical layer. In the considered system model, the base station acts a relay to allow two users at the left side communicate with two users at the right side. By considering imperfect channel state information (CSI), the secure performance need be studied since an eavesdropper wants to overhear signals processed at the downlink. To provide secure performance metric, we derive exact expressions of secrecy outage probability (SOP) and and evaluating the impacts of main parameters on SOP metric. The important finding is that we can achieve the higher secrecy performance at high signal to noise ratio (SNR). Moreover, the numerical results demonstrate that the SOP tends to a constant at high SNR. Finally, our results show that the power allocation factors, target rates are main factors affecting to the secrecy performance of considered uplink-downlink NOMA systems.

Security Analysis in Multicasting over Shadowed Rician and α−μ Fading Channels: A Dual‐hop Hybrid Satellite Terrestrial Relaying Network

In this era of 5G technology, the ever-increasing demands for high data rates lead researchers to develop hybrid satellite-terrestrial (HST) networks as a substitution to the conventional cellular terrestrial systems. Since an HST network suffers from a masking effect which can be mitigated by adopting the terrestrial relaying strategy, in this work, wireless multicasting is focused on through an HST relaying network (HSTRN) in which a satellite sends messages to multiple terrestrial nodes via multiple relays under the wiretapping efforts of multiple eavesdroppers. The concern is to protect the multicast messages from being eavesdropped taking advantage of the well-known opportunistic relaying technique. It is considered that the satellite links follow Shadowed Rician fading whereas the terrestrial links undergo α − μ fading. The secrecy performance of the proposed HSTRN model is accomplished by deriving expressions for the probability of nonzero secrecy multicast capacity, ergodic secrecy multicast capacity, and secure outage probability for multicasting in closed-form. Capitalizing on the derived expressions, the authors analyze how a perfect secrecy level can be preserved in spite of harsh channel conditions and also present a secrecy trade-off in terms of the number of relays, multicast users, and multiple eavesdroppers. Finally, the numerical analyses are corroborated via Monte-Carlo simulations.

A RFID-Integrated Framework for Tag Anti-Collision in UAV-Aided VANETs

In this paper, we investigate tags in anti-collision applications of radio frequency identification (RFID) technology in unmanned aerial vehicle (UAV)-aided vehicular ad hoc networks (VANETs). The integration of RFID technology in UAV-aided VANETs can provide reliable traffic-related services for vehicles. However, multiple tags’ simultaneous responses to a reader mounted on a UAV, denoted as tag collision, gravely affect the correct tag detection on each vehicle. Therefore, in order to decrease the collision probability and improve the throughput, we propose a multi-frequency tag identification method. In the proposed scheme, we devise a tag grouping method based on adaptive power control to make the reader dynamically match the optimal frame length. Based on the above matching results, we introduce a tag estimation method using the optimal weight to improve the accuracy of tag estimation. We theoretically analyze the closed-form expression of the security outage probability expression. Finally, our simulation results demonstrate that the proposed tag anti-collision scheme achieved significant performance superiority in terms of the throughput and identification time slots.

Capacity and outage performance analysis of secure cooperative RF-FSO relaying system in the presence of multiple eavesdroppers

This paper presents the performance analysis of the cooperative radio frequency-free space optical (RF-FSO) relaying system in the presence of multiple eavesdroppers. In this work, the RF link is modeled with Hyper-Gamma (HG) distribution and the FSO link is modeled with unified Gamma–Gamma (ΓΓ) distribution. The RF-FSO combined channel is linked together through a decode-and-forward (DF) based relaying scheme. It is assumed that unknown number of eavesdroppers try to wiretap the confidential data sent from the source by using HG fading channels in the physical layer. The key concern of this work is to ensure safe data transmission through the proposed RF-FSO channel by defending them against passive eavesdropping activities. This work offers the mathematical closed-form expressions of the probability of strictly positive secrecy capacity (PSPSC), secure outage probability (SOP), and average secrecy capacity (ASC) in respect of Meijer’s G function. To acquire better insights into the proposed model, the asymptotic expression of SOP is also provided. Moreover, the impacts of receiver detection type, atmospheric turbulence, pointing error, and eavesdropper signal-to-noise ratio (SNR) on the secrecy performances are investigated in the derived outcomes. The demonstration of the supremacy of the proposed model is done based on the generic nature HG fading channel. Finally, all analytical outputs are checked through Monte Carlo simulations for validation purpose.

Cooperative jamming in downlink satellite network with hardware impairments

AbstractIn this article, a land mobile satellite communication network with an external jammer to fight against the eavesdropper is investigated, where the hardware impairments are introduced to make the analyses more practical. It is worth noting that three jamming schemes, that is, the Gaussian noise jamming, the friendly jamming, and the scheme without jamming, are taken into account to explore the effect of the jammer comprehensively. The secrecy metrics such as the connectivity outage probability (COP), the security outage probability, and the secrecy throughput (ST), are derived for the passive eavesdropping scenario, while the ergodic secrecy capacity is analyzed for the active eavesdropping scenario. Moreover, to get intuitive insight from the closed‐form expressions, the asymptotic ST and the asymptotic COP under the condition of high signal‐to‐noise ratio are also considered. Finally, all the derivations are validated by Monte Carlo simulations, and the effects of different parameters on the performance of the network are analyzed.

On the Physical Layer Security of Mixed FSO-RF SWIPT System With Non-Ideal Power Amplifier

Free-space optical (FSO) links are contemplated as a potential paradigm to yield efficient point-to-point communication in wireless systems. Notably, these links are used to provide the proficient wireless connectivity between the radio frequency (RF) wireless network and the fiber optic-based network. To this end, more attention has been paid to mixed FSO-RF systems where single-hop FSO transmission and single-hop RF transmission configuration is used. In this paper, we propose a mixed FSO-RF dual-hop simultaneous wireless information and power transfer (SWIPT) relaying system in the presence of power amplifier (PA). It is assumed that FSO links suffer from Málaga (M)-turbulence with pointing errors and RF links experience the double shadowed Rician fading. Particularly, the physical layer security is analyzed by deriving the closed-form expressions for secrecy metrics such as secure outage probability, strictly positive secrecy capacity, and secrecy throughput. We consider the three scenarios: 1) FSO-side eavesdropping attack 2) RF-side eavesdropping attack 3) Simultaneous FSO- and RF-side eavesdropping attacks. The asymptotic approximations for the final results are also derived to obtain secrecy diversity order. The effect of SWIPT parameters and PA efficiency on the secrecy performance are then further investigated in detail. In summary, the results show that the reliability and security of the proposed system can be enhanced by utilizing efficient PAs at the RF front end depending on the eavesdropper's location and can also be controlled by the SWIPT parameters.

Secrecy Analysis for Orthogonal Time Frequency Space Scheme Based Uplink LEO Satellite Communication

Recently, satellite communication (Sat-Com) has developed rapidly, and its security is critical. In this letter, we investigate the security performance for an uplink low earth orbit (LEO) Sat-Com system, where the cooperative UAV is employed to send jamming signals against the reconnaissance satellite. In particular, the uplink transmission is based on the orthogonal time frequency space (OTFS) technique, in order to combat the severe Doppler effect caused by the high mobility of the LEO satellite. As a pioneer work, we derive the closed-form expression for the security outage probability (SOP) at the legitimate receiver, where a novel moment matching approach is used for finding a summed probability distribution function (PDF) of the shadowed-Rician (SR) distributed terms. Furthermore, we analyze the SOP advantage achieved by the OTFS scheme over the traditional orthogonal frequency division multiplexing (OFDM) scheme. Simulation results validate the theoretical results for SOP performance of the uplink LEO Sat-Com, and show the effectiveness of employing UAV jammer in terms of enhancing secrecy transmission.

Secure outage probability of cognitive radio network relying non-orthogonal multiple access scheme

This paper studies the secondary network relying relay selection to transmit signal from the secondary source (base station) to two destinations. Especially, two destinations are required non-orthogonal multiple access (NOMA) scheme and it benefits to implementation of the Internet of Things (IoT) systems. However, eavesdropper over-hears signal related link from selected relay to destination. This paper measure secure performance via metric, namely secure outage probability (SOP). In particular, signal to noise ratio (SNR) criterion is used to evalute SOP to provide reliable transmission to the terminal node. Main results indicates that the considered scheme provides performance gap among two signals at destination. The exactness of derived expressions is confirmed via numerical simulation.

Opportunistic Relay in Multicast Channels With Generalized Shadowed Fading Effects: A Physical Layer Security Perspective

Through ordinary transmissions over wireless multicast networks are greatly hampered due to the simultaneous presence of fading and shadowing of wireless channels, secure transmissions can be enhanced by properly exploiting random attributes of the propagation medium. This study focuses on the utilization of those attributes to enhance the physical layer security (PLS) performance of a dual-hop wireless multicast network over κ - μ shadow-fading channel under the wiretapping attempts of multiple eavesdroppers. In order to improve the secrecy level, the best relay selection strategy among multiple relays is employed. Performance analysis is carried out based on the mathematical modeling in terms of analytical expressions of non-zero secrecy capacity probability, secure outage probability, and ergodic secrecy capacity over multicast relay networks. Capitalizing on those expressions, the effects of system parameters, i.e., fading, shadowing, the number of antennas, destination receivers, eavesdroppers, and relays, on the secrecy performance are investigated. Numerical results show that the detrimental impacts caused by fading and shadowing can be remarkably mitigated using the well-known opportunistic relaying technique. Moreover, the proposed model unifies secrecy analysis of several classical models, thereby exhibiting enormous versatility than the existing works.

Secrecy Performance Analysis of a Cognitive Network for IoT over k‐μ Channels

With the development of Internet of Things (IoTs), devices are now connecting and communicating together on a heretofore unheard‐of scale, forming huge heterogeneous networks of mobile IoT‐enabled devices. For beyond 5G‐ (B5G‐) enabled networks, this raises concerns in terms of spectral resource allocation and associated security. Cognitive radio is one effective solution to such a spectrum sharing issue which can be adopted to these B5G networks, which works on the principle of sharing spectrum between primary and secondary users. In this paper, we develop the confidentiality of cognitive radio network (CRNs) for IoT over k‐μ fading channels, with the information transmitted between secondary networks with multiple cooperative eavesdroppers, under the constraint of the maximum interference that the primary users can tolerate. All considered facilities use a single‐antenna receiver. Of particular interest, the minimum limit values of secure outage probability (SOP) and the probability of strictly positive secrecy capacity (SPSC) are developed for this model in a concise form. Finally, the Monte Carlo simulations for the system are provided to support the theoretical analysis presented.

On the Intercept Probability and Secure Outage Analysis of Mixed (α – κ – μ)-Shadowed and Málaga Turbulent Models

This work deals with the secrecy performance analysis of a dual-hop RF-FSO DF relaying network composed of a source, a relay, a destination, and an eavesdropper. We assume the eavesdropper is located close to the destination and overhears the relay’s transmitted optical signal. The RF and FSO links undergo (α-κ-μ)-shadowed fading and unified Málaga turbulence with pointing error. The secrecy performance of the mixed system is studied by deriving closed-form analytical expressions of secure outage probability (SOP), strictly positive secrecy capacity (SPSC), and intercept probability (IP). Besides, we also derive the asymptotic SOP, SPSC, and IP upon utilizing the unfolding of Meijer’s G function where the electrical SNR of the FSO link tends to infinity. Finally, the Monte-Carlo simulation is performed to corroborate the analytical expressions. Our results illustrate that fading, shadowing, detection techniques (i.e. heterodyne detection (HD) and intensity modulation and direct detection (IM/DD)), atmospheric turbulence, and pointing error significantly affect the secrecy performance. In addition, better performance is obtained exploiting the HD technique at the destination relative to IM/DD technique.

On secure transmission in hybrid satellite‐terrestrial cooperative network with untrusted energy harvesting relay and imperfect channel estimation

AbstractIn this paper, the security performance of a hybrid satellite‐terrestrial cooperative network (HSTCN) with untrusted energy limited relay and imperfect channel state information (CSI) is investigated. The satellite and terrestrial links are assumed to follow Shadowed‐Rician fading and Rayleigh fading distributions respectively. The amplify‐and‐forward energy‐limited relay node employs power splitting relaying mode to scavenge energy from its received signals. By considering imperfect CSI between the relay and destination link, maximum ratio combining (MRC) and selection combining (SC) diversity schemes are utilized at the destination to enhance the quality of received signal‐to‐noise ratio (SNR) and aid jamming signal to prevent the untrusted relay from intercepting the satellite confidential data. Thus, to evaluate the HSTCN security performance, the exact analytical closed‐form expressions for the security outage probability (SOP) and connectivity outage probability (COP) are derived for each of the diversity combining techniques. Owing to trade‐off between SOP and COP, the effective secrecy throughput (EST) expression is obtained for the considered diversity schemes with a view to examine the security and reliability performance of the concerned system. Moreover, the impact of system parameters such as transmit SNR, channel coefficient, energy harvesting coefficient, and number of antennas are evaluated. In addition, the results reveal that the MRC has better SOP, COP, and EST performance compare with the SC. Also, it is found that the system EST degrades at high transmit SNR when the number of antennas at satellite is higher. The accuracy of the derived analytical expressions is confirmed by using Monte‐Carlo simulations.

Enhancing multicast security of cognitive radio networks with antenna correlations over Nakagami-m fading channels

In this paper, we investigate the impact of diversity and antenna correlations on the secrecy capacity and outage performance of a cognitive radio multicast network over Nakagami-m fading channels analytically. The proposed network consists of single primary and secondary user, multiple primary and secondary receivers, and multiple eavesdroppers. It is assumed that each user is equipped with single antenna while all the primary and secondary receivers, and eavesdroppers are equipped with multiple antennas. The primary and secondary users transmit their common messages to the respective receivers in the presence of multiple eavesdroppers. A mathematical model is developed to ensure successful reception of confidential information to the primary receivers protecting the activities of eavesdroppers neglecting the effect of interference due to secondary user. In order to analyze the security of the proposed model, closed-form analytical expressions have been derived for the secrecy multicast capacity, the secure outage probability for multicasting and the probability of non-zero secrecy multicast capacity. Analytical results are justified via Monte-Carlo simulations.

Secrecy Analysis of Cognitive Radio Networks over Generalized Fading Channels

At present, the fifth generation (5G) communication networks are in the time of large-scale deployment principally because its characteristics consists of large bandwidth, fast response, and high stability. As a partner of 5G, the Internet of Things (IoT) involves billions of devices around the world, which can make the wireless communication environment more intelligent and convenient. However, the problem that cannot be ignored is the physical layer security of 5G-IoT networks. Based on this, we perform a security analysis of cognitive radio networks (CRN) for IoT, where the CRN is the single-input multiple-output (SIMO) model experiencing κ-μ shadowed fading with multiple eavesdroppers. To analyze the confidentiality of the system under consideration, we analyze the security performance for the considered IoT systems with the help of the derived secure outage probability (SOP) and probability of strictly positive secrecy capacity (SPSC). As a verification of the theoretical formula, Monte Carlo simulation is also provided. The results of great interest are the factors that can produce better security performance in high SNRs region which consist of smaller M, smaller k, and larger N, and larger μ, smaller IP, and smaller Rth.