This paper investigates divide-and-conquer based cooperative jamming for physical-layer security enhancement in the presence of multiple eavesdroppers. Different from previous works, we consider a scenario where the eavesdroppers can be located anywhere inside the communication region of the source, no location information of the eavesdroppers is available and no constraint on the number of eavesdroppers is presupposed. The basic idea is to transmit the message in multiple rounds and exploit the helpful interference from the source and the destination to jam the eavesdroppers in close proximity. Stochastic geometry based analytic results as well as Monte Carlo simulations are presented to illustrate the achievable secrecy performances.
This paper investigates divide-and-conquer based cooperative jamming for physical-layer security enhancement in the presence of multiple eavesdroppers. Different from previous works, we consider a scenario where the eavesdroppers can be located anywhere inside the communication region of the source, no location information of the eavesdroppers is available and no constraint on the number of eavesdroppers is presupposed. The basic idea is to transmit the message in multiple rounds and exploit the helpful interference from the source and the destination to jam the eavesdroppers in close proximity. Stochastic geometry based analytic results as well as Monte Carlo simulations are presented to illustrate the achievable secrecy performances.
This paper investigates cooperative jamming for secure connection in wireless networks. A cooperative jamming strategy is proposed to thwart eavesdroppers anywhere in the network, even if they are located close to the source or the destination. The basic idea is to defeat eavesdroppers by a divide and conquer strategy, and exploit the helpful interference from the source and the destination to circumvent the nearby eavesdropper problem. Analysis and simulation results reveal that this strategy can enhance the secure connection probability and can tolerate any number of independent eavesdroppers provided that the number of legitimate nodes satisfies certain condition.
Cooperative jamming is an approach that has been recently proposed for improving physical layer based security for wireless networks in the presence of an eavesdropper. While the source transmits its message to its destination, a relay node transmits a jamming signal to create interference at the eavesdropper. In this paper, a scenario in which the relay is equipped with multiple antennas is considered. A novel system design is proposed for determining the antenna weights and transmit power of source and relay, so that the system secrecy rate is maximized subject to a total transmit power constraint, or, the transmit power is minimized subject to a secrecy rate constraint. Since the optimal solutions to these problems are difficult to obtain, suboptimal closed-form solutions are proposed that introduce an additional constraint, i.e., the complete nulling of jamming signal at the destination.
The broadcast nature of wireless communications makes the propagation medium vulnerable to security attacks such as eavesdropping and jamming from adversarial or unauthorized users. Applying physical layer secrecy approaches will enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers, without using any secret keys. However, physical layer security approaches are typically feasible only when the source-eavesdropper channel is weaker than the source-destination channel. Cooperative jamming can be used to overcome this challenge and increase the secrecy rate. In this paper, the security of two-phase relaying system with multiple intermediate nodes and in the presence of an eavesdropper is investigated. To enhance the system secrecy rate, a joint cooperative beamforming and jamming combined with relay and jammer selections is proposed. In phase I, the source node broadcasts a signal to relays while three intermediate nodes (which act as jammers) help the source node by transmitting random jamming signals to confuse the eavesdropper. Since the friendly (cooperative) jammers create interference for both the intended relays and the eavesdropper, optimal beamforming is applied such that no interference is caused at two preselected desired relays (that are going to receive the confidential massage in phase I). In phase II, two preselected relays transmit the source message with beamforming coefficients such that the received signal at the eavesdropper is completely nulled out. Our goal in this paper is to minimize the received SNR at the eavesdropper while increasing it at the destination as much as possible by applying different methods such as cooperative beamforming, cooperative jamming and relay selection. To avoid operational complexity, we consider the minimum number of intermediate nodes that are necessary without losing the performance. Numerical results demonstrate the advantage of our proposed scheme compared with the scheme with no cooperative jamming.
In this paper, we enhance physical layer security performance of downlink cellular networks through cooperative jamming technology. Assuming the locations of eavesdroppers (Eve) are available, idle user equipments (UE) are carefully selected to cooperatively transmit jamming signal to confuse eavesdroppers (Eve). Analytical expressions of the connection and secrecy performances are derived, which are validated through Monte Carlo simulations. Simulation results demonstrate that our proposed scheme can improve connection performance, while approaches the secrecy performance of [12]. Furthermore, only 6% idle UEs of [12] are used for cooperative jamming, which helps to decrease energy consumption of network.
Physical (PHY) layer security approaches for wireless communications can prevent eavesdropping without upper layer data encryption. However, they are hampered by wireless channel conditions: absent feedback, they are typically feasible only when the source-destination channel is better than the source-eavesdropper channel. Node cooperation is a means to overcome this challenge and improve the performance of secure wireless communications. This paper addresses secure communications of one source-destination pair with the help of multiple cooperating relays in the presence of one or more eavesdroppers. Three cooperative schemes are considered: decode-and-forward (DF), amplify-and-forward (AF), and cooperative jamming (CJ). For these schemes, the relays transmit a weighted version of a reencoded noise-free message signal (for DF), a received noisy source signal (for AF), or a common jamming signal (for CJ). Novel system designs are proposed, consisting of the determination of relay weights and the allocation of transmit power, that maximize the achievable secrecy rate subject to a transmit power constraint, or, minimize the transmit power subject to a secrecy rate constraint. For DF in the presence of one eavesdropper, closed-form optimal solutions are derived for the relay weights. For other problems, since the optimal relay weights are difficult to obtain, several criteria are considered leading to suboptimal but simple solutions, i.e., the complete nulling of the message signals at all eavesdroppers (for DF and AF), or the complete nulling of jamming signal at the destination (for CJ). Based on the designed relay weights, for DF in the presence of multiple eavesdroppers, and for CJ in the presence of one eavesdropper, the optimal power allocation is obtained in closed-form; in all other cases the optimal power allocation is obtained via iterative algorithms. Numerical evaluation of the obtained secrecy rate and transmit power results show that the proposed design can significantly improve the performance of secure wireless communications.
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.