In this paper, we investigate the secrecy outage performance in simultaneous wireless information and power transfer (SWIPT) systems taking artificial noise assistance into account. Multiple antennas in the source and a single antenna in both the legitimate receiver and the eavesdropper are assumed. Specifically, the transmitted signal at the source is composed of two parts, where the first part is the information symbols and the other is the noise for the eavesdropper. To avoid making noise in the legitimate receiver, these two parts in the transmitted signals are modulated into two orthogonal dimensions according to the instantaneous channel state between the source and the legitimate receiver. We derive an approximate closed-form expression for the secrecy outage probability (SOP) by adopting the Gauss-Laguerre quadrature (GLQ) method, where the gap between the exact SOP and our approximate SOP converges with increase of the summation terms in the GLQ. To obtain the secrecy diversity order and secrecy array gain for the considered SWIPT system, the asymptotic result of the SOP is also derived. This is tight in the high signal-to-noise ratio region. A novel and robust SOP approximation is also analyzed given a small variance of the signal-to-interference-plus-noise ratio at the eavesdropper. Some selected Monte-Carlo numerical results are presented to validate the correctness of the derived closed-form expressions.
In this paper, we investigate the secrecy outage performance in simultaneous wireless information and power transfer (SWIPT) systems taking artificial noise assistance into account. Multiple antennas in the source and a single antenna in both the legitimate receiver and the eavesdropper are assumed. Specifically, the transmitted signal at the source is composed of two parts, where the first part is the information symbols and the other is the noise for the eavesdropper. To avoid making noise in the legitimate receiver, these two parts in the transmitted signals are modulated into two orthogonal dimensions according to the instantaneous channel state between the source and the legitimate receiver. We derive an approximate closed-form expression for the secrecy outage probability (SOP) by adopting the Gauss-Laguerre quadrature (GLQ) method, where the gap between the exact SOP and our approximate SOP converges with increase of the summation terms in the GLQ. To obtain the secrecy diversity order and secrecy array gain for the considered SWIPT system, the asymptotic result of the SOP is also derived. This is tight in the high signal-to-noise ratio region. A novel and robust SOP approximation is also analyzed given a small variance of the signal-to-interference-plus-noise ratio at the eavesdropper. Some selected Monte-Carlo numerical results are presented to validate the correctness of the derived closed-form expressions.
In this paper, the secrecy outage performance of cognitive radio (CR) systems with simultaneous wireless information and power transfer (SWIPT) is investigated, in which non-colluding eavesdroppers (Eves) are randomly located in a 2-dimensional disk and artificial noise is added to safeguard the secrecy performance of the targeted information delivery in the secondary network. The secondary users coexist with primary users in the same bands while the secondary user transmitter (SU-TX) transmits confidential messages to a legitimate receiver (Bob) and energy to multiple energy-receivers (ERs) via the same radio frequency signals. Apart from harvesting energy, these ERs may act as Eves to overhear the confidential information only for Bob. SU-TX equipped with multiple antennas performs beamforming to Bob, which is equipped with multiple antennas and adopts selection combining (SC) scheme. To enhance the secure performance of the considered CR-SWIPT system, SU-TX adds artificial noise (AN) to the original signal designed for Bob according to the instantaneous channel state information (CSI) between SU-TX and Bob, where the artificial noise and original signals for Bob are orthogonal so that Bob can cancel this noise. On ERs’ side, the total received energy for harvesting is not degraded, and a lower signal-to-interference-plus-noise ratio for eavesdropping on the information between SU-TX and Bob is introduced. The approximated closed-form expression for the secrecy outage probability (SOP) is derived by using Gauss-Laguerre quadrature, as well as the asymptotic results are valid in the high signal to noise ratio region. Finally, Monte-Carlo simulations are presented to validate the correctness of the derived analytical results.
Secrecy Analysis in SWIPT Systems Over Generalized-K Fading Channels
In this letter, we investigate the secrecy performance of the simultaneous wireless information and power transfer (SWIPT) system over generalized-K fading channels. After analyzing the communications scenario, we derive the closedform expression for the secrecy outage probability (SOP), and give some simplified expressions for SOP in some special cases. Effective secrecy throughput is also investigated to capture the amount of secure transmitted information. To derive the diversity order, the asymptotic SOP is also analyzed when the average signal-to-noise ratio is sufficiently large. Finally, numerical results are used to validate the correctness of our derived expressions.
Simultaneous wireless information and power transfer (SWIPT) is a major breakthrough in the field of low-power wireless information transmissions. In this paper, the secrecy performance of the SWIPT-enabled relay network with full-duplex destination-aided jamming is assessed, where both the power-splitting (PS) and time-switching (TS) schemes at the relay are considered with the linear and nonlinear energy harvesting models. The relay harvests energy from the confidential signal and artificial noise sent by the source and destination, respectively, and forwards the amplified signal to the destination, in the presence of an eavesdropper. The analytical closed-form expressions of the connection outage probability (COP), secrecy outage probability (SOP), and transmission outage probability (TOP) for PS- and TS-based schemes are derived, and the closed-form expression of the lower bound of ergodic secrecy capacity (ESC) is calculated. The asymptotic-form expressions of the COP, SOP, TOP, and ESC are further analyzed to capture the valuable information in the high SNR regime. Numerical results verify the correctness of analytical results, reveal the effects of the PS/TS ratio, and transmit the signal-to-noise ratio on secrecy performance.
This study examines the wireless communications secrecy performance of multi-user (MU) simultaneous wireless information and power transfer (SWIPT) scheme employing transmit antenna selection (TAS) and maximal-ratio combining (MRC). In order to address the user scheduling requirement of MU-SWIPT scheme, orthogonal frequency-division multiple access (OFDMA) has been utilized, and the secrecy outage probability (SOP) performance is examined via simulations. In the study, it is aimed to examine a realistic scenario where eavesdropper might detect the sub-carrier indices of the legitimate users. In addition, the variation of the SOP performance has been revealed for different values of the number of legitimate users, the number of eavesdropper antennas, the power division factor related to the SWIPT process and the noise variance introduced by the information decoder.
In this article, we investigate the security of a cognitive satellite-terrestrial network that seamlessly integrates simultaneous wireless information and power transfer (SWIPT). The network comprises a secondary system that employs the sophisticated multiple-input multiple-output SWIPT technology. Within shared spectrum, the secondary network's primary objective is to transmit confidential messages to a legitimate receiver (Bob), all the while providing energy to multiple energy receivers, which may act as eavesdroppers. Beamforming techniques and artificial noise schemes are employed to enhance transmission specifically to Bob. The ergodic secrecy capacity (ESC) with the Gauss–Laguerre quadrature approximation method is analyzed. Moreover, the asymptotic results for ESC are investigated including the slope and power offset under high signal-to-noise ratios. Finally, Monte Carlo simulations are presented to affirm the precision and accuracy of the derived analytical models and the proposed analysis.
This paper considers a wirelessly powered wiretap channel, where an energy constrained information source, powered by a dedicated power beacon, communicates with a legitimate user in the presence of a passive eavesdropper. The source is assumed to have multiple antennas, while the other three nodes are equipped with a single antenna each. Considering a simple time-switching design where power transfer and information transmission are separated in time. We investigate two popular transmission schemes, namely maximum ratio transmission (MRT) and transmit antenna selection (TAS). Closed-form expressions are derived for the achievable secrecy outage probability of both schemes. In addition, simple approximations are obtained at the high signal-to-noise ratio (SNR) regime. Our results demonstrate that the more channel state information (CSI) available, the better the secrecy performance. For instance, with full CSI of the main channel, the system can achieve substantial secrecy diversity gain. On the other hand, without the CSI of the main channel, no diversity gain can be attained. Finally, our theoretical claims are validated by the numerical results.