To reduce the secrecy loss due to the correlation between main and wiretap channels, this paper introduces a cooperative jamming relay to degrade the reception at the eavesdropper. We consider slow-fading multiple-input-single-output wiretap channels with a passive single-antenna eavesdropper, where full information for the channels to the legitimate receiver and statistical information for the channels to the eavesdropper is available. By deploying the cooperative jamming relay reasonably, the correlation between the channels from the introduced relay to the legitimate receiver and the eavesdropper can be much below than that between the main and wiretap channels. Thus, the relay can interfere with the eavesdropper more effectively than the traditional scheme of artificial noise-aided beamforming at the transmitter. The simulation results demonstrate that the secrecy outage probability under the transmit power and target secrecy rate constraints is reduced substantially.
To reduce the secrecy loss due to the correlation between main and wiretap channels, this paper introduces a cooperative jamming relay to degrade the reception at the eavesdropper. We consider slow-fading multiple-input-single-output wiretap channels with a passive single-antenna eavesdropper, where full information for the channels to the legitimate receiver and statistical information for the channels to the eavesdropper is available. By deploying the cooperative jamming relay reasonably, the correlation between the channels from the introduced relay to the legitimate receiver and the eavesdropper can be much below than that between the main and wiretap channels. Thus, the relay can interfere with the eavesdropper more effectively than the traditional scheme of artificial noise-aided beamforming at the transmitter. The simulation results demonstrate that the secrecy outage probability under the transmit power and target secrecy rate constraints is reduced substantially.
In physical layer security (PHY-security), the frequently observed high correlation between the main and wiretap channels can cause a significant loss of secrecy. This paper investigates a slow fading scenario, where a transmitter (Alice) sends a confidential message to a legitimate receiver (Bob) while a passive eavesdropper (Eve) attempts to decode the message from its received signal. It is assumed that Alice is equipped with multiple antennas while Bob and Eve each have a single antenna (i.e., a MISOSE system). In a MISOSE system, high correlation results in nearly collinear main and wiretap channel vectors, which help Eve to see and intercept confidential information. Unfortunately, the signal processing techniques at Alice, such as beamforming and artificial noise (AN), are helpless, especially in the extreme case of completely collinear main and wiretap channel vectors. On this background, we first investigate the achievable secrecy outage probability via beamforming and AN at Alice with the optimal power allocation between the information-bearing signal and AN. Then, an ingenious model, in which a cooperative jamming relay (Relay) is introduced, is proposed to effectively mitigate the adverse effects of high correlation. Based on the proposed model, the power allocation between the information-bearing signal at Alice and the AN at Relay is also studied to maximize secrecy. Finally, to validate our proposed schemes, numerical simulations are conducted, and the results show that a significant performance gain with respect to secrecy is achieved.
This paper proposes to employ multiple cooperative jammers to reduce the secrecy loss due to the correlation between main and wiretap channels. We consider slow-fading multiple-input single-output (MISO) wiretap channels with a passive single-antenna eavesdropper, in which an independent transmitter side and correlated receiver side are assumed. Considering that signal processing techniques as well as the blind growth of power at the source play a limited role in reducing the secrecy loss due to the receiver-side correlation, multiple cooperative jammers equipped with multiple antennas are introduced into the system. Owing to spatial diversity, the channel correlation from the different jammers to the destination and the eavesdropper varies. To interfere with the reception at the eavesdropper efficiently and consequently enhance security, some jammers in favorable channel conditions are selected to emit artificial noise (AN) with power optimization. Based on this, the secrecy outage probability is analyzed. The simulation results verify that the proposed scheme of multiple cooperative jammers provides substantial gains in terms of secrecy.
This paper investigates cooperative security for slow-fading channels, where the source sends confidential messages to the destination with the assistance of a cooperative jammer coexisting with multiple passive eavesdroppers. Assuming that accurate legitimate channel information and statistical illegitimate channel information are available with an independent transmitter side and a highly correlated receiver side, we propose a correlation-based cooperative jamming approach to reduce the secrecy loss due to receiver-side correlation. In particular, the correlation is considered to be a resource for acquiring more knowledge about illegitimate channels, based on which the statistical distribution of illegitimate channels is described more precisely. Then, the power of artificial noise in the null space of the legitimate channel from the jammer to the destination is placed more reasonably rather than as a simple uniform distribution. Additionally, a correlation-based beamformer is designed for transmitting the information-bearing signal. Finally, the achievable secrecy rate under a secrecy outage constraint is computed. The numerical results confirm that the proposed scheme achieves a performance improvement in terms of secrecy rate under a secrecy outage constraint when the receiver side is highly correlated.
An artificial-noise (AN)-aided beamformer for reducing secrecy loss due to the correlation between the main and wiretap channels is designed in this letter. We consider slow-fading multiple-input-single-output wiretap channels with a passive single-antenna eavesdropper, where the source has accurate main channel information and statistical wiretap channel information. By exploiting the channel correlation, the power of the AN in the null space of the main channel can be placed more reasonably instead of using a simple uniform distribution. Then, an efficient algorithm for power allocation between the information-bearing signal and the AN is developed. The simulation results show that the secrecy rate under the transmit power and secrecy outage constraint is improved.
An artificial noise (AN)-aided beamformer specific to correlated main and wiretap channels is designed in this paper. We consider slow-fading multiple-input-single-output wiretap channels with multiple passive single-antenna eavesdroppers in which an independent transmitter side and correlated receiver side are assumed. Additionally, the source has accurate main channel information and statistical wiretap channel information. To reduce the secrecy loss due to receiver-side correlation, this paper proposes a channel-correlation-enabled transmission optimization scheme. In particular, the correlation is viewed as a resource to acquire more knowledge about wiretap channels. Based on this, the statistical distribution of wiretap channels is described more precisely, and an elaborate channel-correlation-enabled AN-aided beamformer is designed. Then, the achievable secrecy rate under transmit power and secrecy outage constraints is derived. Finally, the study is also extended to a specific scenario of multiple-antenna eavesdroppers. Simulation results show that the secrecy rate under transmit power and secrecy outage constraints can be improved under high correlation.
Cooperative jamming approach has been commonly used in the field of physical layer security to achieve a good secrecy rate of wireless networks. In this approach, the Gaussian noise signal sent by a friendly jammer can disrupt the reception of the eavesdropper, however, it may also interfere with the legitimate receiver. In this paper, we propose a novel approach, namely, information jamming, to go beyond the secrecy rate achieved by the traditional cooperative jamming approach in a multiple-input single-output (MISO) wiretap channel. We propose that a multi-antenna friendly jammer transmits the source message rather than Gaussian noise signal for simultaneously enhancing the signal strength at the legitimate receiver and canceling the received signal at the eavesdropper. In particular, we aim to maximize the achievable secrecy rate by optimizing the information jammer's beamforming vector. Though the optimization problem is non-convex, we successfully solve it optimally via a two-stage based numerical approach. To gain more useful analytical results, we also propose two suboptimal jamming schemes with low computation, by targeting at improving the legitimate reception and avoiding the eavesdropping, respectively. Finally, numerical results show that the proposed information jamming approach significantly helps go beyond the secrecy rate of the existing cooperative jamming approach, especially when the transmit power of the jammer is large enough.