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.
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.
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.
This paper investigates cooperative security in wireless networks, where a source (Alice) intends to transmit a confidential message to a legitimate destination (Bob), with the help of a cooperative jammer (Charlie), coexisting with multiple passive eavesdroppers (Eves). In particular, by assuming knowledge of Bob's perfect channel state information (CSI) but only Eves’ statistical CSIs, secrecy beamforming with artificial noise (AN) is utilized for secure transmission, and cooperative jamming (CJ) is explored to further enhance secrecy. We first derive an accurate closed-form expression for the secrecy outage probability (SOP), and establish the condition under which positive secrecy rate is achievable. Then, we provide a secure transmit design for maximizing the SOP constrained secrecy rate. Moreover, based on a strict mathematical analysis, we characterize the impact of the main channel quality and the number of Eves on transmit design and secrecy performance. Specifically, optimal power allocation ratio between the information-bearing signal and the AN signal increases as the main channel quality improves, and decreases with the number of Eves. Numerical results confirm that our design achieves performance improvement in terms of both secrecy rate and secure energy efficiency, as compared to the approach without CJ.
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.
In this paper, we consider physical layer security in wireless communication networks in which a source (Alice) intends to send a confidential message to a legitimate destination (Bob) with the help of a cooperative jammer (CJ), in the presence of a passive eavesdropper (Eve). Assuming that only statistical channel state information (CSI) of Eve is available, artificial-noise (AN) assisted beamforming and cooperative jamming are designed. The goal is to maximize the secrecy rate, subject to a constraint on secrecy outage probability. Numerical results validate the effectiveness of our scheme. Moreover, a higher secure energy efficiency (EE) can be achieved as compared with other schemes without a cooperative jammer.
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.
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.