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.
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.
In this study, we investigate the physical layer secrecy performance of RF energy harvesting (EH) networks over Rayleigh fading channels. The RF-EH system considered here consists of one power transfer station, one source, one destination, and multiple passive eavesdroppers. The source harvests energy from the power transfer station and transmits the information to the destination by using a time switching-based relaying protocol. The eavesdroppers try to extract the transmitted information without an active attack. By using the statistical characteristics of the signal-to-noise ratio (SNR), the exact closed-form expressions of the existence probability of the secrecy capacity and the secrecy outage probability are derived. Further, we analyze the secrecy performance of the system with respect to various system parameters, such as the location of the system elements and the number of eavesdroppers. Finally, the equivalent Monte Carlo simulation results are provided to confirm the correctness of our calculations.
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.
Nowadays, physical layer secrecy has become the new approach to enhance information security of wireless networks and have attracted the attention of lot of researchers in the world. This paper investigates the physical layer secrecy performance of radio frequency energy harvesting (RF-EH) networks over Rayleigh fading channels. The considered RF-EH system consists of multiple power transfer stations, one source and multiple destinations in the presence of multiple passive eavesdroppers. The best power transfer station and the best received signal at destination is selected among multiple power transfer stations and among multiple destinations respectively. By using statistical characteristics of the signal-to-noise ratio (SNR), the exact closed-form expressions of existence probability of secrecy capacity and secrecy outage probability are derived. Finally, simulation results confirm an agreement between our analysis and equivalent Monte-Carlo simulations.
In this paper, we analyze the secrecy capacity of a half-duplex energy harvesting (EH)-based multi-antenna amplify-and-forward relay network in the presence of a passive eavesdropper. During the first phase, while the source is in the transmission mode, the legitimate destination transmits an auxiliary artificial noise (AN) signal which has two distinct purposes: 1) to transfer power to the relay and 2) to improve system security. Since the AN is known at the legitimate destination, it is easily cancelled at the intended destination, which is not the case at the eavesdropper. In this respect, we derive new exact analytical expressions for the ergodic secrecy capacity for various well-known EH relaying protocols, namely, time switching relaying (TSR), power splitting relaying (PSR), and ideal relaying receiver (IRR). Monte Carlo simulations are also provided throughout our investigations to validate the analysis. The impacts of some important system parameters, such as EH time, power splitting ratio, relay location, AN power, EH efficiency, and the number of relay antennas, on the system performance are investigated. The results reveal that the PSR protocol generally outperforms the TSR approach in terms of the secrecy capacity.
In this paper, we investigate the physical layer security (PLS) of a wireless sensor network (WSN) that consists of a base station (BS), multiple sensor nodes (SNs), and multiple energy-limited relays (ERs) in the presence of a passive eavesdropper (EAV). We adopt a time-switching/power-splitting (TSPS) mechanism for information transmission. The communication protocol is divided into two phases. The purpose of the first phase is to decode information, and energy harvesting (EH) is performed in accordance with the TSPS protocol. The purpose of the second phase is to transmit information to multiple destinations using the amplify-and-forward (AF) technique. In this study, we introduce a multirelay cooperative scheme (MRCS) to improve the secrecy performance. We derive analytical expressions for the secrecy outage probability (SOP) of the MRCS and that of the noncooperative relay scheme (NCRS) by using the statistical characteristics of the signal-to-noise ratio (SNR). Specifically, we propose an optimal relay selection scheme to guarantee the security of the system for the MRCS. In addition, Monte Carlo simulation results are presented to confirm the accuracy of our analysis based on simulations of the secrecy performance under various system parameters, such as the positions and number of ERs, the EH time, and the EH efficiency coefficients. Finally, the simulation results show that the secrecy performance of our MRCS is higher than that of the NCRS and the traditional cooperative relay scheme (TCRS).
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.