In this letter, we propose a learning-based wireless powered secure transmission, in which a source utilizes energy harvested from a power beacon to communicate with a legitimate receiver, in the presence of an eavesdropper. In order to confuse the eavesdropper, we assume that the source transmits the artificial noise signals, in addition to the information signals. We first characterize the effective secrecy throughput of our system, showing its dependence on the transmission parameters, including the fraction of time allocated for wireless power transfer, the fraction of power allocated to the information signals, as well as the wiretap code rates. We then leverage the deep feedforward neural network to learn how the optimal transmission parameters that jointly maximize the effective secrecy throughput can be obtained. Through numerical results, we demonstrate that our learning-based scheme can achieve almost the same secrecy performance as the optimal solution obtained from the exhaustive search, while requiring much less computational complexity.
In this letter, we propose a learning-based wireless powered secure transmission, in which a source utilizes energy harvested from a power beacon to communicate with a legitimate receiver, in the presence of an eavesdropper. In order to confuse the eavesdropper, we assume that the source transmits the artificial noise signals, in addition to the information signals. We first characterize the effective secrecy throughput of our system, showing its dependence on the transmission parameters, including the fraction of time allocated for wireless power transfer, the fraction of power allocated to the information signals, as well as the wiretap code rates. We then leverage the deep feedforward neural network to learn how the optimal transmission parameters that jointly maximize the effective secrecy throughput can be obtained. Through numerical results, we demonstrate that our learning-based scheme can achieve almost the same secrecy performance as the optimal solution obtained from the exhaustive search, while requiring much less computational complexity.
This paper investigates a wireless powered secure communication network (WPSCN), in which the legitimate users have no constant energy supply and need to be wireless powered for information transmitting. The harvest-then-transmit protocol is adopted in the WPSCN, i.e., the energy access point (EAP) first transfers energy to legitimate users through energy beamforming, and then, the legitimate users transmit their data to the information access point (IAP) by time-division multiple access. Since an eavesdropper intercepts users’ uplink information, the EAP creates artificial noise to cripple the interception capability of the eavesdropper. For providing a secrecy throughput balancing across different legitimate users, we aim to maximize the minimum secrecy throughput of all users via time allocation, energy beamforming, and artificial noise design. To this end, a low-complexity two-stage algorithm is proposed. In the first stage, without taking into account the eavesdropper's wiretapping, we design time allocation and energy beamforming by solving the problem of minimum throughput maximization, which is convex and can be easily solved. In the second stage, two easily implementable strategies are proposed for artificial noise design so as to strengthen the noise power at the eavesdropper and simultaneously reduce the noise power at the IAP. Simulation results show that the performance of the proposed approach is close to the upper bound and not sensitive to scenario settings, which confirms the effectiveness of the proposed method.
This paper considers the secrecy communication of a wirelessly powered network, where an energy-constrained legitimate transmitter (Alice) sends message to a legitimate receiver (Bob) with the energy harvested from a dedicated power beacon, while an eavesdropper (Eve) intends to intercept the information. A simple time-switching protocol with a time-switching ratio α is used to supply power for the energy-constrained legitimate transmitter. To improve the physical layer security, we first propose a protocol that combines maximum ratio transmission with zero-forcing (ZF) jamming for the case without Eve's channel state information (CS!), i.e., Alice has access to Bob's CSI only. Then, we propose a protocol that uses a ZF transmitting strategy to minimize the signal-to-noise ratio (SNR) at Eve for the case that Alice is capable of obtaining partial CSI related to Eve. Closed-form expressions and simple approximations of the connection outage probability and secrecy outage probability are derived for both protocols. Furthermore, the secrecy throughput as well as the diversity orders achieved by our proposed protocols are characterized, and the optimal time-switching ratio α and power allocation coefficient β for secrecy throughput maximization are derived in the high SNR regime. Finally, numerical results validate the effectiveness of the proposed schemes.
This paper investigates secure transmission in a wireless powered communication network (WPCN) with an energy harvesting (EH) source configured with multiple antennas. In the WPCN, the EH source harvests energy from the radio frequency (RF) signals broadcasted by a power beacon (PB), and purely relies on the harvested energy to communicate with the destination in the presence of passive eavesdroppers. It is noteworthy that the RF-EH source is equipped with a finite energy storage to accumulate the harvested energy for the future usage. Moreover, due to energy-constraint and complexity- limitation, the multi-antenna source is only configured with a single RF-chain. To enhance the security for the WPCN, we propose two adaptive transmission schemes, i.e., energy-aware transmit antenna selection (EATAS) and energy-aware differential spatial modulation (EADSM). According to the energy status and the channel quality, the source adaptively decides whether to transmit confidential information or harvest RF energy. To evaluate the secrecy performance of the proposed schemes, we first study the evolution of the energy storage, and then derive the analytical expressions of connection outage probability (COP), secrecy outage probability (SOP) and efficient secrecy throughput (EST). Numerical results demonstrate that our proposed schemes outperform the existing schemes, i.e., time-switching based TAS (TS-TAS) and accumulate-then-transmit (ATT). And, increasing the transmit power of the PB or the capacity of the source's energy storage is helpful to improve the secrecy performance. Moreover, there exists an optimal transmission rate for each proposed scheme to achieve best secrecy performance.
In this paper, we consider a secrecy wireless powered communication network, where an information source (IS) transmits message to a legitimate information receiver (IR) with the energy it harvests from the energy source (ES) and a full-duplex (FD) active eavesdropper (AE) performs eavesdropping and jamming simultaneously with the energy it harvests from the ES. With a goal to maximize the achievable secrecy rate, we jointly optimize the energy beamforming and the artificial noise (AN) beamforming at the ES, the information beamforming at the IS and the energy transfer time at the ES. Numerical results are given to show the superiority of our proposed scheme.
This paper proposes a novel power beacon-assisted wiretap channel, where an energy constrained source, powered by a dedicated power beacon, aims to establish secure communications with a legitimate user in the presence of an eavesdropper. The power beacon and the source are assumed to have multiple antennas, while the legitimate user and the eavesdropper are equipped with a single antenna each. Considering a time-switching protocol, the power beacon first charges the source through wireless power transfer, and then acts as a friendly jammer to assist the source for secure communication. Depending on the available channel state information (CSI) at the power beacon, we propose several different jamming schemes for secrecy performance enhancement. Closed-form expressions are derived for the achievable secrecy outage probability of the proposed schemes. In addition, simple and accurate approximations are obtained at the high signal-to-noise ratio regime. The outcomes suggest that jamming is an effective approach to improve the secrecy performance: with full CSI available at the power beacon, employing simple zero-forcing scheme attains significant secrecy diversity gain and without the CSI of the eavesdropper link, jamming provides only some array gain. Moreover, we show that the proposed limited feedback-based random beamforming is an effective approach, which may outperform the antenna selection scheme. Furthermore, numerical results reveal that there exists a unique time switching ratio that maximizes the effective secrecy throughput.
This letter studies the secure communication between a wireless powered source node and a destination node in the presence of multiple eavesdroppers. We propose a hybrid base station (BS) scheme where the hybrid BS first transfers wireless power to the source and then performs cooperative jamming while the source transmits the information signal using the harvested energy. We maximize the secrecy throughput by jointly optimizing the time allocation, source transmit power, and redundancy rate under the secrecy constraint and transmit power constraint. We transform the secrecy throughput maximization problem into a convex optimization problem and obtain the optimal solutions efficiently. Numerical results illustrate that our solution is superior to other benchmark schemes.