Security and energy are two critical Issues for emerging wireless networks and thus we study wireless energy harvesting and physical-layer security for a spectrum-sharing network with a multi-antenna full-duplex secondary receiver in the presence of an eavesdropper. We adopt a time-switching strategy where in the first phase, secondary users are powered through wireless energy transfer from the primary source. In the second phase, the secondary transmitter and receiver use the harvested energy to transmit the information and jamming signal, respectively. We propose a beamforming scheme at the secondary receiver with the main purpose of minimizing the outage probability of the secondary data transmission and maximizing the achievable secrecy rate of the primary system. We derive analytical expression for the outage probability at the secondary receiver and the achievable secrecy rate of the primary network. Moreover, asymptotic closed-form outage probability is presented. Numerical simulations verify the performance of the proposed scheme and analytical results and allow us to investigate the impact of the key system parameters on the network performance.
Security and energy are two critical Issues for emerging wireless networks and thus we study wireless energy harvesting and physical-layer security for a spectrum-sharing network with a multi-antenna full-duplex secondary receiver in the presence of an eavesdropper. We adopt a time-switching strategy where in the first phase, secondary users are powered through wireless energy transfer from the primary source. In the second phase, the secondary transmitter and receiver use the harvested energy to transmit the information and jamming signal, respectively. We propose a beamforming scheme at the secondary receiver with the main purpose of minimizing the outage probability of the secondary data transmission and maximizing the achievable secrecy rate of the primary system. We derive analytical expression for the outage probability at the secondary receiver and the achievable secrecy rate of the primary network. Moreover, asymptotic closed-form outage probability is presented. Numerical simulations verify the performance of the proposed scheme and analytical results and allow us to investigate the impact of the key system parameters on the network performance.
This work investigates the secure transmission in the wireless information and power transfer system where a source node communicates with a wireless-powered full-duplex destination node in the presence of a passive eavesdropper. In particular, we propose such a two-phase time-sharing (TS) secure communication protocol: in the first phase, energy harvesting is conducted from the source node to the destination node, while in the second phase, the source node transmits information-bearing signal under the protection of artificial noise sent from the destination node. It is worth to mention that the energy of this artificial noise at the destination node is converted from the harvested energy in the first phase and self-interference exists at the destination in the second phase. We derive the closed-form expressions for the connection outage probability (COP), the secrecy outage probability (SOP) and the transmission outage probability (TOP), based on which the secrecy throughput is formulated. Further, we determine the optimal time allocation factor and the optimal codeword transmission rate to maximize the secrecy throughput with dual outage constraints. Finally, numerical results verifies our results and exams the effect of the time allocation factor and the codeword transmission rate on the performance.
We consider an underlay cognitive radio system, in which a source in a secondary system transmits information to a full-duplex (FD) wireless-powered destination node in the presence of an eavesdropper. In particular, the destination node is equipped with a single receiving antenna and a single transmitting antenna to enable FD operation. The receiving antenna can simultaneously receive information and energy from the source through power-splitter architecture. The received energy is then used in the transmitting antenna to send jamming signals to degrade the eavesdropper’s decoding capacity. Upper and lower bounds of probability of strictly positive secrecy capacity (SPSC) have been derived. Numerical results show that under the condition that the interference from the source and destination at primary user’s receiver is smaller than the interference temperature limit, upper and lower bounds merge together to become the exact SPSC.
In this paper, we investigate the secrecy performance of energy-constrained wireless-powered networks with considering the passive eavesdropping scenario, where the simultaneous wireless information and power transfer-based full-duplex self-jamming (SWIPT-FDSJ) scheme is developed. The maximal ratio transmission protocol is applied at the multi-antenna source such that the wireless signals are designated to the destination directly. Besides, the energy harvesting and full-duplex self-jamming operations are adopted at the energy-constrained destination to prolong its lifetime as well as to confuse the eavesdropper. Specifically, the exact and asymptotic closed-form expressions of the connection outage probability (COP), the secrecy outage probability (SOP), and the secrecy throughput of the proposed system are obtained, based on which we optimize the time-switching ratio to maximize the secrecy throughput. We also degenerate the proposed SWIPT-FDSJ scheme to the reduced half-duplex with no self-jamming (HDNSJ) scheme. The finds suggest that in the HDNSJ scheme, adding the antenna number of the source only benefits the COP performance, but has no impact on the SOP performance. By contrast, it will promote the COP and SOP performance at the same time in the SWIPT-FDSJ scheme, which eventually results in the great improvement of secrecy throughput. In addition, we present the practical application condition of the SWIPT-FDSJ scheme. It is demonstrated that the secrecy throughput performance of the SWIPT-FDSJ scheme is much superior to the HDNSJ scheme on condition that the application condition is satisfied.
In this paper, we investigate physical layer security, where a source node communicates with a wireless powered full-duplex destination node using multiple subcarriers in the presence of an eavesdropper. The destination node adopts the time switching technique to coordinate information decoding and energy harvesting, and can use the harvested energy to send jamming signals to interfere with the eavesdropper. We investigate the problem of optimizing transmit power allocation at the source node, the transmit power allocation for jamming at the destination node and the time allocation for maximizing the secrecy rate, and propose an iterative algorithm to solve the optimization problem. It is shown by simulation results that the proposed algorithm greatly outperforms other reference algorithms.
In order to provide privacy provisioning for the secondary information, we propose an energy harvesting based secure transmission scheme for the cognitive multi-relay networks. In the proposed scheme, two secondary relays harvest energy to power the secondary transmitter and assist the secondary secure transmission without interfere the secondary transmission. Specifically, the proposed secure transmission policy is implemented into two phases. In the first phase, the secondary transmitter transmits the secrecy information and jamming signal through the power split method. After harvesting energy from a fraction of received radio-frequency signals, one secondary relay adopts the amplify-and-forward relay protocol to assist the secondary secure transmission and the other secondary relay just forwards the new designed jamming signal to protect the secondary privacy information and degrade the jamming interference at the secondary receiver. For the proposed scheme, we first analyze the average secrecy rate, the secondary secrecy outage probability, and the ergodic secrecy rate, and derive their closed-form expressions. Following the above results, we optimally allocate the transmission power such that the secrecy rate is maximized under the secrecy outage probability constraint. For the optimization problem, an AI based simulated annealing algorithm is proposed to allocate the transmit power. Numerical results are presented to validate the performance analytical results and show the performance superiority of the proposed scheme in terms of the average secrecy rate.
In this paper, the physical-layer security of a cooperative wireless system with multi-antenna full-duplex (FD) destination is examined. More specifically, we consider a cooperative transmission scenario in which a source communicates with a destination through a relay in the presence of an eavesdropper. In order to degrade the wiretap channel, the FD destination simultaneously transmits an interference signal towards the eavesdropper, while receiving information from the relay. A joint transmit and receive beamformer design is proposed to maximize the signal-to-interference-plus-noise ratio (SINR) at the destination, while guaranteeing that the SINR at the eavesdropper is below a certain threshold. We reformulate the optimization problem as a semidefinite relaxation problem in terms of a transmit beamforming matrix. To balance the performance and system complexity, we investigate suboptimum beamforming designs based on zero-forcing criterion. We derive exact closed-form expressions for the average secrecy rates of the proposed suboptimum designs. Our results reveal that optimum and suboptimum beamforming schemes along with friendly jamming significantly improve the secrecy performance. Moreover, simulation results demonstrate that the optimum scheme outperforms suboptimum schemes, especially in high transmit power regimes.