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, 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, 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.
The broadcast nature of the wireless medium allows unintended users to eavesdrop on confidential information transmission. In this regard, we investigate the problem of secure communication between a source and a destination via a wireless energy harvesting untrusted node that acts as a helper to relay the information; however, the source and destination nodes wish to keep the information confidential from the relay node. To realize the positive secrecy rate, we use destination-assisted jamming. Being an energy-starved node, the untrusted relay harvests energy from the received radio-frequency (RF) signals, which include the source's information signal and the destination's jamming signal. Thus, we utilize the jamming signal efficiently by leveraging it as a useful energy source. At the relay, to enable energy harvesting and information processing, we adopt power splitting (PS) and time switching (TS) policies. To evaluate the secrecy performance of this proposed scenario, we derive analytical expressions for two important metrics, viz., the secrecy outage probability and the ergodic secrecy rate. The numerical analysis reveals design insights into the effects of different system parameters such as PS ratio, energy harvesting time, target secrecy rate, transmit signal-to-noise ratio (SNR), relay location, and energy conversion efficiency factor, on secrecy performance. Specifically, the PS policy achieves better optimal secrecy outage probability and optimal ergodic secrecy rate than that of the TS policy at higher target secrecy rate and transmit SNR, respectively.
This paper investigates secure communications of energy harvesting untrusted relay networks, where the destination assists jamming signal to prevent the untrusted relay from eavesdropping and to improve the forwarding ability of the energy constrained relay. Firstly, the source and the destination transmit the signals to the relay with maximal ratio transmission (MRT) technique or transmit antenna selection (TAS) technique. Then, the destination utilizes maximal ratio combining (MRC) technique or receive antenna selection (RAS) technique to receive the forwarded information. Therefore, four transmission and reception schemes are considered. For each scheme, the closed-form expressions of the secrecy outage probability (SOP) and the connection outage probability (COP) are derived. Besides, the effective secrecy throughput (EST) metric is analyzed to achieve a good tradeoff between security and reliability. In addition, the asymptotic performance of EST is also considered at the high signal-to-noise ratio (SNR). Finally, simulation results illustrate that: (1) the EST of the system with MRT and MRC scheme are superior to other schemes, however, in the high SNR regime, the EST of the system with MRT scheme is inferior to TAS; and (2) for the source node, there exists an optimal number of antennas to maximize the EST of the proposed schemes.
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.
This paper studies the secrecy performance of an energy-harvesting relaying system in the presence of a dualuse source node and an eavesdropper.Specifically, the source has dual roles in the dual-hop communication: 1) to transmit confidential information in the first hop; 2) to generate jamming signal to interfere the eavesdropper in the second hop.Moreover, the multi-antenna relay deploys a power-splitting harvesting scheme to coordinate the information receiving and energy harvesting, and adopts maximal ratio combining technique to process the multiple copies of signals.Considering decode-andforward protocol and transmit antenna selection scheme, we derive an analytical expression for secrecy outage probability, and perform Monte Carlo simulation to validate the analysis.Analytical results show that the SOP performance with the dualuse source node can be effectively improved when the relaydestination channel does not have absolute advantage over the relay-eavesdropper channel.
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.