In this paper, we propose a novel scheme of grouping cooperative jamming(CJ) for secure communication. During the data transmission, the source broadcasts its information signal, all the helpers simultaneously transmit common artificial noise(AN) to interfere the eavesdropper for tradition CJ. In our scheme, all the helpers are divided to different groups which transmit independent artificial noises to the potential eavesdropper. The zero-forcing beamfomer is selected to cancel the AN out at the destination. The tradition CJ scheme can not completely consume the total power budget, while the grouping scheme is based on the instantaneously channel gain which can make best of the total power per group. The simulations show that our propose scheme based on minimum distance achieves the highest secrecy rate and the power actual consumed approaches to the total power budget. Additionally, we propose a fixed grouping scheme based on the second-order statistics of the channel gain which can be easily implemented. Furthermore, we consider the case that the eavesdropper has knowledge of the artificial noise. The tradition CJ does not work in such case, while our scheme works well even only one group keeps its AN secret. The analytical results and simulations show our scheme achieves better performance than the tradition CJ.
In this paper, we propose a novel scheme of grouping cooperative jamming(CJ) for secure communication. During the data transmission, the source broadcasts its information signal, all the helpers simultaneously transmit common artificial noise(AN) to interfere the eavesdropper for tradition CJ. In our scheme, all the helpers are divided to different groups which transmit independent artificial noises to the potential eavesdropper. The zero-forcing beamfomer is selected to cancel the AN out at the destination. The tradition CJ scheme can not completely consume the total power budget, while the grouping scheme is based on the instantaneously channel gain which can make best of the total power per group. The simulations show that our propose scheme based on minimum distance achieves the highest secrecy rate and the power actual consumed approaches to the total power budget. Additionally, we propose a fixed grouping scheme based on the second-order statistics of the channel gain which can be easily implemented. Furthermore, we consider the case that the eavesdropper has knowledge of the artificial noise. The tradition CJ does not work in such case, while our scheme works well even only one group keeps its AN secret. The analytical results and simulations show our scheme achieves better performance than the tradition CJ.
In this paper, we propose a novel scheme of grouping cooperative jamming (CJ) for secure communication. During the data transmission, the source broadcasts its information signal, all the helpers simultaneously transmit common artificial noise (AN) to interfere the eavesdropper for tradition CJ. In our scheme, all the helpers are divided to different groups which transmit independent artificial noises to the potential eavesdropper. The zero-forcing beamfomer is selected to cancel the AN out at the destination. The tradition CJ scheme can not completely consume the total power budget, while the grouping scheme is based on the instantaneously channel gain which can make best of the total power per group. The simulations show that our propose scheme based on minimum distance achieves the highest secrecy rate and the power actual consumed approaches to the total power budget. Additionally, we propose a fixed grouping scheme based on the second-order statistics of the channel gain which can be easily implemented. Furthermore, we consider the case that the eavesdropper has knowledge of the artificial noise. The tradition CJ does not work in such case, while our scheme works well even only one group keeps its AN secret. The analytical results and simulations show our scheme achieves better performance than the tradition CJ.
This paper considers cooperative jamming (CJ) to ensure secure communication between the transmitter and the legitimate receiver. CJ serves as an effective and promising way to confuse the eavesdropper. However, in the presence of the CJ, the secrecy capacity is obtained at a certain cost of power, which consists of two parts: one part is the extra power consumed by transmitting CJ, and the other part is the signal-to-noise ratio (SNR) loss caused by imperfect CJ cancellation at the authorized receiver, which can be equivalent to the wasted power of the desired signal. In this paper, we both take into account the imperfect CJ cancellation and the extra power penalty to analyze the secrecy capacity, which can be a measurement of system security performance. Numerical simulation is adopted, revealing that the proposed scheme reduces the proportion of power used to transmit jamming signals, and achieves almost the same secrecy capacity as the case which does not take the extra power penalty into consideration. Moreover, the channel capacity of the desired signal is improved.
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.
We consider a cooperative wireless network in the presence of one or more eavesdroppers, and exploit node cooperation for achieving physical (PHY) layer based security. Two different cooperation schemes are considered. In the first scheme, cooperating nodes retransmit a weighted version of the source signal in a decode-and-forward (DF) fashion. In the second scheme, referred to as cooperative jamming (CJ), while the source is transmitting, cooperating nodes transmit weighted noise to confound the eavesdropper. We investigate two objectives: i) maximization of the achievable secrecy rate subject to a total power constraint and ii) minimization of the total power transmit power under a secrecy rate constraint. For the first design objective, we obtain the exact solution for the DF scheme for the case of a single or multiple eavasdroppers, while for the CJ scheme with a single eavesdropper we reduce the multivariate problem to a problem of one variable. For the second design objective, existing work introduces additional constraints in order to reduce the degree of difficulty, thus resulting in suboptimal solutions. Our work raises those constraints, and obtains either an analytical solution for the DF scheme with a single eavesdropper, or reduces the multivariate problem to a problem of one variable for the CJ scheme with a single eavesdropper. Numerical results are presented to illustrate the proposed results and compare them to existing work.
In this paper, we consider the multiple-input single-output (MISO) wiretap channel with a cooperative jammer (CJ). Motivated by the fact that corrupting pilot signals can effectively degrade the channel estimation at the eavesdropper (Eve), we emphasize that the physical-layer security can be enhanced by introducing jamming signals in pilot phase. Therefore, we propose a cooperative jamming scheme which delivers artificial noise (AN) both in pilot and data phases, unlike the conventional schemes that transmit AN only in data phase. More specifically, we optimize the jamming power allocation between pilot phase and data phase, along with designing the beamforming vector at the CJ. Furthermore, considering the limitation of energy budget at the CJ, the energy efficiency of the proposed scheme is investigated based on the circuit power consumption model. Finally, numerical results verify the performance of the proposed scheme, in terms of secrecy rate and energy efficiency.
In this paper, we investigate 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 node (Charlie), in the presence of multiple independent eavesdroppers (Eves). In particular, cooperative jamming (CJ) is explored to enhance secure communication between Alice and Bob. We provide a transmit design to maximize the secrecy rate, subject to a secrecy outage probability (SOP) constraint. Specifically, we establish a condition under which positive secrecy rate can be guaranteed. In addition to secrecy rate performance, we also pay attention to the secure energy efficiency, defined as the ratio of secrecy rate to total power consumption. Numerical results validate the effectiveness and energy efficiency of our proposed CJ scheme.