Biblio

In this paper, physical-layer security (PLS) of an underlay cognitive radio network (CRN) operating over cascaded Rayleigh fading channels is examined. In this scenario, a secondary user (SU) transmitter communicates with a SU receiver through a cascaded Rayleigh fading channel while being exposed to eavesdroppers. By harvesting energy from the SU transmitter, a cooperating jammer attempts to ensure the privacy of the transmitted communications. That is, this harvested energy is utilized to generate and spread jamming signals to baffle the information interception at eavesdroppers. Additionally, two scenarios are examined depending on the manner in which eavesdroppers intercept messages; colluding and non-colluding eavesdroppers. These scenarios are compared to determine which poses the greatest risk to the network. Furthermore, the channel cascade effect on security is investigated. Distances between users and the density of non-colluding eavesdroppers are also investigated. Moreover, cooperative jamming-based energy harvesting effectiveness is demonstrated.

In this paper, we study an underlay Cognitive Radio (CR) system with energy harvesting over Nakagami-m fading channel. This system consists of a secondary source, a secondary receiver, a primary receiver and a single eavesdropper. The source in the secondary network has one antenna and transmits information to the secondary receiver equipped with two separated antennas to operate in a Full-Duplex (FD) mode. The upper and lower bounds for the Strictly Positive Secrecy Capacity (SPSC) are derived and the numerical results demonstrate that the performance of the proposed system can be improved by increasing the average channel power gain between the source and the destination. Here, the lower and upper bounds are merged to form the exact SPSC when the total interference is below a predefined limit.

This paper investigates the secrecy outage performance of Multiple Input Multiple Output (MIMO) secondary nodes for underlay Cognitive Radio Network (CRN) over α–μ fading channel. Here, the proposed system consists of one active eavesdropper and two primary nodes each with a single antenna. The power of the secondary transmitter depends on the harvested energy from the primary transmitter to save more energy and spectrum. Moreover, a Transmit Antenna Selection (TAS) scheme is adopted at the secondary source, while the Maximal Ratio Combining (MRC) technique is employed at the secondary receiver to optimize the quality of the signal. A lower bound closed-form phrase for the secrecy outage performance is derived to demonstrate the effects of the channel parameters. In addition, numerical results illustrate that the number of source transmit antennas, destination received antenna, and the eavesdropper received antenna have significant effects on improving the secrecy performance.

The electromagnetic energy harvesting technology is a new and effective way to supply power to the condition monitoring sensors installed on or near the transmission line. We will use Computer Simulation Technology Software to simulate the different designs of stand-alone electromagnetic energy harvesters The power generated by energy harvesters of different design structures is compared and analyzed through simulation and experimental results. We then propose an improved design of energy harvester.

Cognitive radio primary network secure communication strategy based on secondary user energy harvesting and primary user destination assistance is investigated to guarantee primary user secure communication in cognitive radio network. In the proposed strategy, the primary network selects the best secondary user to forward the traffic from a primary transmitter (PT) to a primary receiver (PR). The best secondary user implements beamforming technique to assist primary network for secure communication. The remaining secondary transmitters harvest energy and transmit information to secondary receiver over the licensed primary spectrum. In order to further enhance the security of primary network and increase the harvested energy for the remaining secondary users, a destination-assisted jamming signal transmission strategy is proposed. In this strategy, artificial noise jamming signal transmitted by PR not only confuses eavesdropper, but also be used to power the remaining secondary users. Simulation results demonstrate that, the proposed strategy allows secondary users to communicate in the licensed primary spectrum. It enhances primary network secure communication performance dramatically with the joint design of secondary user transmission power and beamforming vectors. Furthermore, physical layer security of primary and secondary network can also be guaranteed via the proposed cognitive radio primary network secure communication strategy.

Physical-layer security (PLS) for an underlay cognitive radio network (CRN)-based simultaneous wireless information and power transfer (SWIPT) over cascaded κ-µ fading channels is investigated. The network is composed of a pair of secondary users (SUs), a primary user (PU) receiver, and an eavesdropper attempting to intercept the data shared by the SUs. To improve the SUs’ data transmission security, we assume a full-duplex (FD) SU destination, which employs energy harvesting (EH) to extract the power required for generating jamming signals to be emitted to confound the eavesdropper. Two scenarios are presented and compared; harvesting and non-harvesting eavesdropper. Moreover, a trade-off between the system’s secrecy and reliability is explored. PLS is studied in terms of the probability of non-zero secrecy capacity and the intercept probability, whereas the reliability is studied in terms of the outage probability. Results reveal the great impact of jamming over the improvement of the SUs’ secrecy. Additionally, our work indicates that studying the system’s secrecy over cascaded channels has an influence on the system’s PLS that cannot be neglected.

We investigate cognitive radio networks where the unlicensed sender operates in the overlay mode to relay the information of the licensed transmitter as well as send its individual information. To secure information broadcasted by the unlicensed sender against the wire-tapper, we invoke jammers to limit eavesdropping. Also, to exploit efficiently radio frequency energy in licensed signals, we propose the unlicensed sender and all jammers to scavenge this energy source. To assess the security measures of both licensed and unlicensed networks, we first derive rigorous closed-form formulas of licensed/unlicensed secrecy outage probabilities. Next, we validate these formulas with Monte-Carlo simulations before using them to achieve insights into the security capability of the proposed jamming-aided energy harvesting cognitive radio networks in crucial system parameters.

Simultaneous Wireless Information and Power Transfer (SWIPT) technique is introduced in Radio Frequency (RF) communication to carry both information and power in same medium. In this approach, the energy can be harvested while decoding the information carries in an RF wave. Recently, the same concept applied in Visible Light Communication (VLC) namely Simultaneous Light Wave Information and Power Transfer (SLIPT), which is highly recommended in an indoor applications to overcome the problem facing in RF communication. Thus, SLIPT is introduced to transmit the power through a Light Emitting Diode (LED) luminaries. In this work, we compare both SWIPT and SLIPT technologies and realize SLIPT technology archives increased performance in terms of the amount of harvested energy, outage probability and error rate performance.

We address secure resource allocation for the energy harvesting (EH) based 5G cooperative cognitive radio networks (CRNs). To guarantee that the size-limited secondary users (SUs) can simultaneously send the primary user's and their own information, we assume that SUs are equipped with orthogonally dual-polarized antennas (ODPAs). In particular, we propose, develop, and analyze an efficient resource allocation scheme under a practical non-linear EH model, which can capture the nonlinear characteristics of the end-to-end wireless power transfer (WPT) for radio frequency (RF) based EH circuits. Our obtained numerical results validate that a substantial performance gain can be obtained by employing the non-linear EH model.

Unmanned aerial vehicles (UAVs) based cognitive radio (CR) systems improve the sensing performance. However, such systems demand secure communication with lower power consumption. Motivated by these observations, we consider an energy-constraint yet energy harvesting (EH) drone flying periodically in the circular track around primary transmitter in the presence of an eavesdropper with an aim to use the licensed band opportunistically. Considering the trade-off between the residual energy and secondary link performance, we formulate the constrained optimization problem, i.e., maximizing residual energy under the constraint of secondary secrecy outage. Simulation results verify the proposed theoretical analysis.

Underwater sensor networks (UWSN) are a division of classical wireless sensor networks (WSN), which are designed to accomplish both military and civil operations, such as invasion detection and underwater life monitoring. Underwater sensor nodes operate using the energy provided by integrated limited batteries, and it is a serious challenge to replace the battery under the water especially in harsh conditions with a high number of sensor nodes. Here, energy efficiency confronts as a very important issue. Besides energy efficiency, data privacy is another essential topic since UWSN typically generate delicate sensing data. UWSN can be vulnerable to silent positioning and listening, which is injecting similar adversary nodes into close locations to the network to sniff transmitted data. In this paper, we discuss the usage of compressive sensing (CS) and energy harvesting (EH) to improve the lifetime of the network whilst we suggest a novel encryption decision method to maintain privacy of UWSN. We also deploy a Mixed Integer Programming (MIP) model to optimize the encryption decision cases which leads to an improved network lifetime.

In this paper, secrecy outage probability (SOP) of cooperative communications in ESCRNs is numerically evaluated by the recommended precise closed-form formula which is corroborated by numerous computer simulations. Results expose that the relay's location, energy scavenging time, message recovering time, and power division for energy scavenging and message recovering dramatically impact the SOP of the cooperative communications in ESCRNs. Moreover, results infer that the SOP is constant either in energy scavenging non-cognitive networks (ES-nonCRNs) or in ESCRNs with infinite power transmitters.

In this paper, we propose an exact closed-form expression of secrecy outage probability (SOP) for underlay cognitive network with energy scavenging capable relay over Nakagami-m fading channels and under both (maximum transmit and interference) power constraints. Various results validated the proposed expression and shed insights into the security performance of this network in key specifications.

In order to be more environmentally friendly, a lot of parts and aspects of life become electrified to reduce the usage of fossil fuels. This can be seen in the increased number of electrical vehicles in everyday life. This of course only makes a positive impact on the environment, if the electricity is produced environmentally friendly and comes from renewable sources. But when the green electrical power is produced, it still needs to be transported to where it's needed, which is not necessarily near the production site. In China, one of the ways to do this transport is to use High Voltage Direct Current (HVDC) technology. This of course means, that the current has to be converted to DC before being transported to the end user. That implies that the converter stations are of great importance for the grid security. Therefore, a precise monitoring of the stations is necessary. Ideally, this could be accomplished with wireless sensor nodes with an autarkic energy supply. A role in this energy supply could be played by a thermoelectrical generator (TEG). But to assess the power generated in the specific environment, a simulation would be highly desirable, to evaluate the power gained from the temperature difference in the converter station. This paper proposes a method to simulate the generated power by combining a model for the generator with a Computational Fluid Dynamics (CFD) model converter.

Distributed consensus is a prototypical distributed optimization and decision making problem in social, economic and engineering networked systems. In collaborative applications investigating the effects of adversaries is a critical problem. In this paper we investigate distributed consensus problems in the presence of adversaries. We combine key ideas from distributed consensus in computer science on one hand and in control systems on the other. The main idea is to detect Byzantine adversaries in a network of collaborating agents who have as goal reaching consensus, and exclude them from the consensus process and dynamics. We describe a novel trust-aware consensus algorithm that integrates the trust evaluation mechanism into the distributed consensus algorithm and propose various local decision rules based on local evidence. To further enhance the robustness of trust evaluation itself, we also introduce a trust propagation scheme in order to take into account evidences of other nodes in the network. The resulting algorithm is flexible and extensible, and can incorporate more complex designs of decision rules and trust models. To demonstrate the power of our trust-aware algorithm, we provide new theoretical security performance results in terms of miss detection and false alarm rates for regular and general trust graphs. We demonstrate through simulations that the new trust-aware consensus algorithm can effectively detect Byzantine adversaries and can exclude them from consensus iterations even in sparse networks with connectivity less than 2f+1, where f is the number of adversaries.

In Cooperative Networks based on simultaneous wireless information and power transfer (SWIPT), relay nodes collect the energy of radio signals received from source node and transmit the information of source nodes to destination nodes, which not only prolongs the service life of energy-constrained nodes, but also improves the ability of long-distance transmission of information. Due to the openness of energy harvesting, there may be eavesdropping users with malicious decoding. In order to study the security performance of the Cooperative Networks based on SWIPT, this paper mainly studies the physical layer security performance of this network, derives and simulates the expression of system security outage probability and throughput. The simulation results show that the system security performance is mainly influenced by time allocation parameter of SWIPT and decreases with the increase of target rate.

This paper investigates the secrecy outage performance of an energy harvesting-based dual-hop amplify-and-forward (AF) mixed radio-frequency/underwater optical wireless communication (RF/UOWC) system. A single-antenna source node (S) is considered, communicating with one legitimate destination node (D) with the aid of a multi-antenna AF relay (R) device. In this setup, the relay node receives the incoming signal from S via an RF link, which is subject to Nakagami-m fading, then performs maximal-ratio-combining (MRC) followed by a fixed-gain amplification, before transmitting it to the destination via a UOWC link, subject to mixture Exponential-Gamma fading. Assuming the presence of a malicious eavesdropper attempting to intercept the S- R hop, a tight approximate expression for the secrecy outage probability is retrieved. The derived results provide useful insights into the influence of key system parameters on the secrecy outage performance. Our analytical results are corroborated through computer simulations, which verifies their validity.

We address secure resource allocation for an OFDMA cooperative cognitive radio network (CRN) with energy harvesting (EH) capability. In the network, one primary user (PU) cooperates with several untrusted secondary users (SUs) with one SU transmitter and several SU receivers, where the SU transmitter and all SU receivers may overhear the PU transmitter's information while all SU receivers may eavesdrop on each other's signals. We consider the scenario when SUs are wireless devices with small physical sizes; therefore to improve system performance we suppose that SUs are equipped with co-located orthogonally dual-polarized antennas (ODPAs). With ODPAs, on one hand, the SU transmitter can first harvest energy from radio frequency (RF) signals emitted by the PU transmitter, and then utilize the harvested energy to simultaneously serve the PU and all SU receivers. On the other hand, by exploiting polarization-based signal processing techniques, both the PU's and SUs' physical-layer security can be enhanced. In particular, to ensure the PU's communication security, the PU receiver also sends jamming signals to degrade the reception performance of SUs, and meanwhile the jamming signals can also become new sources of energy powering the SU transmitter. For the considered scenario, we investigate the joint allocation of subcarriers, powers, and power splitting ratios to maximize the total secrecy rate of all SUs while ensuring the PU's minimum secrecy rate requirement. Finally, we evaluate the performance of our resource allocation scheme through numerical analyses.