In this paper, we investigate the secrecy performance of an energy harvesting relay network, where a legitimate source communicates with a legitimate destination via the assistance of multiple trusted relays. In the considered system, the source and relays deploy the time-switching based radio frequency energy harvesting technique to harvest energy from a multi-antenna beacon. Different antenna selection and relay selection schemes are applied to enhance the security of the system. Specifically, two relay selection schemes based on the partial and full knowledge of channel state information are proposed. The exact closed-form expressions of the systems secrecy outage probability in these schemes are derived. A Monte-Carlo based simulation validates our analysis results.
In this paper, we investigate the secrecy performance of an energy harvesting relay network, where a legitimate source communicates with a legitimate destination via the assistance of multiple trusted relays. In the considered system, the source and relays deploy the time-switching based radio frequency energy harvesting technique to harvest energy from a multi-antenna beacon. Different antenna selection and relay selection schemes are applied to enhance the security of the system. Specifically, two relay selection schemes based on the partial and full knowledge of channel state information are proposed. The exact closed-form expressions of the systems secrecy outage probability in these schemes are derived. A Monte-Carlo based simulation validates our analysis results.
In this paper, we investigate the secrecy performance of an energy harvesting relay system, where a legitimate source communicates with a legitimate destination via the assistance of multiple trusted relays. In the considered system, the source and relays deploy the time-switching-based radio frequency energy harvesting technique to harvest energy from a multi-antenna beacon. Different antenna selection and relay selection schemes are applied to enhance the security of the system. Specifically, two relay selection schemes based on the partial and full knowledge of channel state information, i.e., optimal relay selection and partial relay selection, and two antenna selection schemes for harvesting energy at source and relays, i.e., maximizing energy harvesting channel for the source and maximizing energy harvesting channel for the selected relay, are proposed. The exact and asymptotic expressions of secrecy outage probability in these schemes are derived. We demonstrate that applying relay selection approaches in the considered energy harvesting system can enhance the security performance. In particular, optimal relay selection scheme outperforms partial relay selection scheme and achieves full secrecy diversity order, regardless of energy harvesting scenarios.
In this paper, the secrecy performance of a wireless-powered multi-antenna relaying system, which consists of a source(S), a destination(D),N(N>1)relays (Rs), a power beacon(B), and an eavesdropper(E), is studied in the presence of imperfect channel state information at Rs. Both S and Rs are assumed to be with nonlinear energy harvesters, and harvest energy from radio-frequency signals from B through a time-switching harvesting scheme. Assuming Rs deploy decode-and-forward scheme, a generalKth best relay in terms of instantaneous secrecy capacity for S-R-D link is selected for information transmission. An analytical expression for secrecy outage probability (SOP), validated via Monte Carlo simulation, is derived when all channels experience independent Rayleigh fading. Numerical results show that a higher correlation coefficient between the estimated and real channel values leads to better SOP performance when the ratio of the channel gains of R-D and R-E links is in the high region for the first hop or in the low-to-medium region for the second hop. Furthermore, there exists a special value of the saturation threshold of the energy harvester at S or R, and SOP performance cannot be improved when the saturation threshold is beyond that value.
In this paper, we study radio frequency energy harvesting (EH) in a wireless sensor network in the presence of multiple eavesdroppers (EAVs). Specifically, the sensor source and multiple sensor relays harvest energy from multiple power transfer stations (PTSs), and then, the source uses this harvested energy to transmit information to the base station (BS) with the help of the relays. During the transmission of information, the BS typically faces a risk of losing information due to the EAVs. Thus, to enhance the secrecy of the considered system, one of the relays acts as a jammer, using harvested energy to generate interference with the EAVs. We propose a best-relay-and-best-jammer scheme for this purpose and compare this scheme with other previous schemes. The exact closed-form expression for the secrecy outage probability (SOP) is obtained and is validated through Monte Carlo simulations. A near-optimal EH time algorithm is also proposed. In addition, the effects on the SOP of key system parameters such as the EH efficiency coefficient, the EH time, the distance between the relay and BS, the number of PTSs, the number of relays, and the number of EAVs are investigated. The results indicate that the proposed scheme generally outperforms both the best-relay-and-random-jammer scheme and the random-relay-and-best-jammer scheme in terms of the secrecy capacity.
In this paper, we present a secrecy outage performance analysis of wireless powered communication networks with multiple eavesdroppers, where an energy-limited information source with multiple antennas harvests the radio frequency (RF) energy from a dedicated power beacon (PB) before transmission. To exploit the benefits of multiple antennas at source, two popular multi-antenna transmission schemes, i.e., maximal ratio transmission and transmit antenna selection, are investigated for two intercepting ways at Eves, i.e., non-colluding and colluding scenarios, respectively. Specifically, adopting the time-switching protocol at PB, we derive exact and asymptotic closed-form expressions of the secrecy outage probability for both two transmission schemes taking into account the outdated channel state information (CSI). From our analysis, several important concluding remarks are obtained as follows: a) Full secrecy diversity order can be achieved by both two transmission schemes with no feedback delay, however, it reduces to zero in the presence of feedback delay; b) MRT scheme always outperforms TAS scheme with no feedback delay. However, TAS scheme achieves a similar performance as MRT scheme or even better in moderate and even serious feedback delay conditions.
This paper proposes a secure wireless communication system that integrates Physical Layer Security (PLS) with Energy Harvesting (EH) to improve both data confidentiality and network sustainability. The system model consists of a source node S, powered by energy harvested from spatially distributed power stations, a multi-antenna destination node D, and an eavesdropper node E located within the communication range. A time-switching protocol enables the source node S to alternate between energy harvesting and secure data transmission. To enhance signal quality and system security, the destination node D employs Selection Combining (SC) and Maximal Ratio Combining (MRC) techniques to mitigate fading effects and eavesdropping risks. Analytical expressions for the Signal-to-Noise Ratios (SNRs) at both the destination D and the eavesdropper E are derived, along with the Probability Density Function (PDF) and Cumulative Distribution Function (CDF) of these SNRs under block Rayleigh fading conditions. Furthermore, an exact analytical formulation for Secrecy Outage Probability (SOP) is presented, quantifying the probability of information leakage under various system configurations. The proposed model is validated through extensive Monte Carlo simulations, which confirm the accuracy of the mathematical analysis of SOP. Based on simulation results, the impact of key system parameters—such as energy harvesting efficiency η, time-switching protocol parameter α, the number of antennas M at the destination node, and the number of beacon nodes N—on SOP is analyzed. The results provide valuable insights for optimizing secure and energy-efficient communication in wireless networks.
This paper investigates the physical layer secrecy performance of radio frequency (RF) energy harvesting (EH) relaying networks based on the combination of time switching-adaptive power splitting (TSAPS) and best relay selection (BRS) schemes. Specifically, the system consists of one source, one destination and multiple energy-constrained decode-and-forward (DF) relays which help the source transmit information to the destination, in the presence of a passive eavesdropper. In this setting, the relays harvest RF energy from the source signal to power their relaying transmission, in which power splitting ratio self-adjustment policy and best relay selection scheme are utilized. To characterize the secrecy performance, the exact closed-form expressions of secrecy outage probability for random relay selection and best relay selection are derived. In addition, the comparison to random relay selection is presented to verify the efficiency in terms of secrecy outage probability of the proposed protocol. Finally, the numerical and simulation results are also provided to evaluate the impact of the key parameters on the secrecy performance and confirm the correctness of our analysis.