In this paper, a novel transmission scheme is proposed to improve the security of downlink cellular network. The confidential message intended to one of K mobile users (MUs) should be securely kept from the undesired recipients. In this work, the K-1 remaining users are regarded as potential eavesdroppers and called as internal eavesdroppers. For the security enhancement, we propose an adaptation of a single cooperative jammer (CJ) to increase the ambiguity at all malicious users by distracting them with artificial interference. With the help of CJ, we derive the optimal joint transmission scheme by beamforming solution to maximize the secrecy rate of the intended user. Numerical results show the performance improvement of the proposed scheme.
In this paper, a novel transmission scheme is proposed to improve the security of downlink cellular network. The confidential message intended to one of K mobile users (MUs) should be securely kept from the undesired recipients. In this work, the K-1 remaining users are regarded as potential eavesdroppers and called as internal eavesdroppers. For the security enhancement, we propose an adaptation of a single cooperative jammer (CJ) to increase the ambiguity at all malicious users by distracting them with artificial interference. With the help of CJ, we derive the optimal joint transmission scheme by beamforming solution to maximize the secrecy rate of the intended user. Numerical results show the performance improvement of the proposed scheme.
In this paper, we consider a cooperative jammer to improve secrecy of the wireless transmission in a cellular downlink network. The private message intended for a single user should be kept from the remainder of the users who are regarded as internal eavesdroppers. To improve the secrecy of the intended user, we propose an employment of a helper with multiple antennas and design its optimal transmit beamforming vector. Specifically, the helper node generates the artificial interference to the internal eavesdroppers and so enhances the security by increasing the ambiguity at the eavesdroppers. Based on a framework of power gain region in [1], we optimize the transmission strategy for the helper which maximizes the secrecy capacity of the intended user. The analytical and simulation results show that the proposed scheme enhances the secrecy capacity. In addition, all users whose secrecy rates are zero with no helper's cooperation can achieve the positive secrecy rate by the proposed scheme.
We consider the K-user cellular network coexisting with a single helper node (HN) (or cooperative jammer) whose objective is to enhance the secrecy of the confidential data transmission. Due to the broadcast nature of the wireless medium, the information leakage to the undesired users is unavoidable when the base station (BS) transmits the private information to the intended mobile user (MU). In this paper, the unintended users are regarded as the potential eavesdroppers and called as the internal eavesdroppers. In [1], the proposed optimal transmission strategy for the helper maximizes the secrecy capacity of the intended user. However, its computational complexity geometrically increases as the number of the legitimate users or the network size grows. This property is inappropriate to the cellular network where dozens of users generally exist. To resolve such practical issue, we design the low complexity transmission strategies of the helper which are insensitive to the network size. In addition, as a part of an effort to develop the usability, we classify the helper's cooperation according to whether the helper possesses the channel state information (CSI) about the downlink channel BS → MUkfor k ∈ K = {1, 2, …, K} or not. We analyze the computational complexity of the proposed schemes and verify that their complexity dramatically decreases compared to the optimal transmission strategy in [1]. Also, through the simulation results, it is observed that the proposed transmission strategies provide the comparable secrecy rates to that of the optimal transmission.
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.
In this paper, we consider secure downlink transmission in two-cell networks where the one base station (Alice) provides secure wireless services to its legitimate receiver (Bob) in the presence of a passive eavesdropper (Eve). For multi-cell networks, the inter-cell interference to Bob and Eve has a great impact on the security performance. In order to improve the confidentiality of information transfer from Alice to Bob, it is crucial to properly design the transmit strategies. With the results of conventional cooperative jamming (CJ) scheme, we propose a modified CJ scheme for cooperative base station (CBS) to further degrade the quality of signal reception at Eve, and therefore the secrecy rate can be increased. Both theoretical analysis and numerical results show that the modified CJ scheme outperforms the conventional CJ scheme by achieving a higher secrecy rate. Additionally, by taking the energy efficiency into account, we formulate an adaptive cooperation, in which the CBS is allowed to provide services to its desired receiver. We design a cooperative beamforming for CBS to satisfy the rate requirement while maximizing the secrecy rate of legitimate channel. Numerical results validate the effectiveness of the proposed cooperation scheme.
In this paper, we explore how to enhance the physical layer security performance in downlink cellular networks through cooperative jamming technology. Idle user equipments (UE) are used to cooperatively transmit jamming signal to confuse eavesdroppers (Eve). We propose a threshold-based jammer selection scheme to decide which idle UE should participate in the transmission of jamming signal. Threshold conditions are carefully designed to decrease interference to legitimate channel, while maintain the interference to the Eves. Moreover, fewer UE are activated, which is helpful for saving energy consumptions of cooperative UEs. Analytical expressions of the connection and secrecy performances are derived, which are validated through Monte Carlo simulations. Theoretical and simulation results reveal that our proposed scheme can improve connection performance, while approaches the secrecy performance of [12]. Furthermore, only 43% idle UEs of [12] are used for cooperative jamming, which helps to decrease energy consumption of network.
In this paper, we investigate the secrecy performance of cooperative wireless communication networks, where a source (Alice) intends to transmit information to a legitimate user (Bob) with an unmanned aerial vehicle (UAV) enabled friendly jammer in the presence of a passive eavesdropper (Eve). In order to maximize the secrecy rate of the system under a certain secrecy outage probability, we design a scheme utilizing artificial-noise (AN) beamforming and cooperative jamming to determine the optimal power allocation factor with only location and statistical channel state information of the Eve. Numerical results validate that the proposed scheme can significantly improve the secrecy rate and secure energy efficiency (EE) performance.