We propose a two-phase artificial-noise-aided scheme to power a single-antenna energy-harvesting source node (Alice) and secure her transmissions to a multiple-antenna legitimate destination (Bob) in the presence of a multiple-antenna eavesdropper (Eve). A one-time pad (OTP) encryption scheme is used to ensure the security of the source's information signal. In our proposed scheme, Bob sends a secret key to Alice then Alice uses an OTP encryption scheme to secure her transmissions. If Alice can correctly decode the secret key and has stored enough energy to ensure reliable information transmission (i.e., ensure no outages on her link to Bob), she sends her data packet to Bob. To secure the key signal from the eavesdropper, Bob uses a hybrid fast-fading and slow-fading multiplicative artificial-noise scheme. Power allocation between the multiplicative noise and the desired signal and time allocation between the two transmission phases are investigated.
We propose a two-phase artificial-noise-aided scheme to power a single-antenna energy-harvesting source node (Alice) and secure her transmissions to a multiple-antenna legitimate destination (Bob) in the presence of a multiple-antenna eavesdropper (Eve). A one-time pad (OTP) encryption scheme is used to ensure the security of the source's information signal. In our proposed scheme, Bob sends a secret key to Alice then Alice uses an OTP encryption scheme to secure her transmissions. If Alice can correctly decode the secret key and has stored enough energy to ensure reliable information transmission (i.e., ensure no outages on her link to Bob), she sends her data packet to Bob. To secure the key signal from the eavesdropper, Bob uses a hybrid fast-fading and slow-fading multiplicative artificial-noise scheme. Power allocation between the multiplicative noise and the desired signal and time allocation between the two transmission phases are investigated.
We propose an artificial-noise (AN)-aided transmission scheme to achieve two objectives: 1) energize a single-antenna legitimate transmitter (Alice) by receiving an AN signal from a multi-antenna base-station (Bob) and 2) secure the information signal transmitted from Alice to Bob from eavesdropping by a multi-antenna eavesdropper (Eve). We assume a two-phase transmission scheme. In the first phase, Bob transmits two orthogonal precoded AN vectors to power Alice and confuse Eve. In the second phase, Alice transmits her information signal to Bob along with an amplified version of the AN signal to confuse Eve. Our numerical results show that the proposed scheme can efficiently power Alice while securing her transmissions. Moreover, we show that the achieved average secrecy rate under the proposed scheme outperforms the case when the conventional communication scheme is employed.
We propose a new scheme to secure a wireless-powered untrusted cooperative-communication network, where a legitimate source node (Alice) transmits her information messages to a legitimate destination node (Bob) through the multiple amplify-and-forward untrusted relays. The relay nodes are assumed to be honest but curious nodes; hence, they are trusted at the service level but are untrusted at the information level. To reduce the energy consumption of the network, only one relay node is selected in each time slot to forward Alice's information signal. We assume a power-splitting-based energy-harvesting scheme, where each relay node splits its received signal into information and energy streams. Since the relay nodes are assumed to be untrusted at the information level, they attempt to decode the information intended to Bob while harvesting energy at the same time. When the relaying mode is selected, the scheme is realized over two non-overlapping time phases. To prevent any information leakage to the untrusted relay nodes, Bob and a cooperative jammer (John) inject jamming (artificial noise) signals during the first phase. During the second phase, the untrusted relay nodes that will not be forwarding the information signal must harvest energy to accumulate more energy to help Alice in future time slots. Moreover, the cooperative jammer will jam the untrusted relays to further power their batteries and prevent them from decoding the information-forwarding relay signal in case they decided to cheat and decode it. We model the battery state transitions at each relay as a finite-state Markov chain and analyze it. Our numerical results show the security gains of our proposed scheme relative to two benchmark schemes.
In this article, we propose a lightweight security scheme for ensuring both information confidentiality and transmission resiliency in the Internet-of-Things (IoT) communication. A single-antenna transmitter communicates with a half-duplex single-antenna receiver in the presence of a sophisticated multiple-antenna-aided passive eavesdropper and a multiple-antenna-assisted hostile jammer (HJ). A low-complexity artificial noise (AN) injection scheme is proposed for drowning out the eavesdropper. Furthermore, for enhancing the resilience against HJ attacks, the legitimate nodes exploit their own local observations of the wireless channel as the source of randomness to agree on shared secret keys. The secret key is utilized for the frequency hopping (FH) sequence of the proposed communication system. We then proceed to derive a new closed-form expression for the achievable secret key rate (SKR) and the ergodic secrecy rate (ESR) for characterizing the secrecy benefits of our proposed scheme, in terms of both information secrecy and transmission resiliency. Moreover, the optimal power sharing between the AN and the message signal is investigated with the objective of enhancing the secrecy rate. Finally, through extensive simulations, we demonstrate that our proposed system model outperforms the state-of-the-art transmission schemes in terms of secrecy and resiliency. Several numerical examples and discussions are also provided to offer further engineering insights.
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.
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.
This letter studies the physical-layer security of a full-duplex (FD) multiple-input multiple-output relay channel. A legitimate source node (Alice) communicates with her destination node (Bob) through an FD relay node in the presence of a cooperative FD jammer and a potential eavesdropper (Eve). The cooperative jammer is assumed to be an FD node that is solely charged by the ambient radio-frequency transmissions. We investigate the self-energy recycling at the cooperative jammer and derive a sufficient condition for the cooperative jammer to operate as a node with reliable energy supply. Without knowing the eavesdropper's channel state information at the legitimate nodes, we propose a precoded artificial-noise (AN) injection scheme to secure the legitimate transmissions. The numerical results demonstrate that our proposed AN-aided secure scheme achieves a significant average secrecy rate improvement compared with the case of no cooperative jammer.