In this paper, we investigate physical layer security of a multicast network consisting of multiple legitimate users in the presence of an eavesdropper. Besides information receivers, the legitimate users are assumed to be able to act as jammers for interfering with the eavesdropper to improve secrecy. The joint user selection and power control problem for maximizing the average sum secrecy rate of the multicast network under the transmit power constraints is investigated with perfect channel state information (CSI) or with unknown CSI related to the eavesdropper, and heuristic algorithms are proposed correspondingly. Simulation results are presented to verify the proposed algorithms. It is shown that the proposed algorithms significantly outperform the reference algorithms in terms of average sum secrecy rate.
In this paper, we investigate physical layer security of a multicast network consisting of multiple legitimate users in the presence of an eavesdropper. Besides information receivers, the legitimate users are assumed to be able to act as jammers for interfering with the eavesdropper to improve secrecy. The joint user selection and power control problem for maximizing the average sum secrecy rate of the multicast network under the transmit power constraints is investigated with perfect channel state information (CSI) or with unknown CSI related to the eavesdropper, and heuristic algorithms are proposed correspondingly. Simulation results are presented to verify the proposed algorithms. It is shown that the proposed algorithms significantly outperform the reference algorithms in terms of average sum secrecy rate.
Recently, physical layer security has been recognized as a new design paradigm to provide security in wireless networks. In contrast to the existing conventional cryptographic methods, physical layer security exploits the dynamics of fading channels to enhance security of wireless communications. This paper studies optimization frameworks for a multicasting network in which a transmitter broadcasts the same information to a group of legitimate users in the presence of multiple eavesdroppers. In particular, power minimization and secrecy rate maximization problems are investigated for a multicasting secrecy network. First, the power minimization problem is solved for different numbers of legitimate users and eavesdroppers. Next, the secrecy rate maximization problem is investigated with the help of private jammers to improve the achievable secrecy rates through a game theoretic approach. These jammers charge the transmitter for their jamming services based on the amount of interference caused to the eavesdroppers. For a fixed interference price scenario, a closed-form solution for the optimal interference requirement to maximize the revenue of the transmitter is derived. This rate maximization problem for a nonfixed interference price scenario is formulated as a Stackelberg game in which the jammers and transmitter are the leaders and follower, respectively. For the proposed game, a Stackelberg equilibrium is derived to maximize the revenues of both the transmitter and the private jammers. To support the derived theoretical results, simulation results are provided with different numbers of legitimate users and eavesdroppers. In addition, these results show that physical layer security based jamming schemes could be incorporated in emerging and future wireless networks to enhance the quality of secure communications.
In this paper, we examine the physical layer security for cooperative wireless networks with multiple intermediate nodes, where the decode-and-forward protocol is considered. We propose a new joint relay and jammer selection (JRJS) scheme for protecting wireless communications against eavesdropping, where an intermediate node is selected as the relay for the sake of forwarding the source signal to the destination and meanwhile, the remaining intermediate nodes are employed to act as friendly jammers, which broadcast the artificial noise for disturbing the eavesdropper. We further investigate the power allocation among the source, relay and friendly jammers for maximizing the secrecy rate of proposed JRJS scheme, and derive a closed-form sub-optimal solution. Specifically, all the intermediate nodes, which successfully decode the source signal, are considered as relay candidates. For each candidate, we derive the sub-optimal closed-form power allocation solution and obtain the secrecy rate result of the corresponding JRJS scheme. Then, the candidate, which is capable of achieving the highest secrecy rate, is selected as the relay. Two assumptions about the channel state information (CSI), namely the full CSI (FCSI) and partial CSI (PCSI), are considered. Simulation results show that the proposed JRJS scheme outperforms the conventional pure relay selection, pure jamming, and generalized singular-value-decomposition-based beamforming schemes in terms of secrecy rate. Additionally, the proposed FCSI-based power allocation and PCSI-based power allocation schemes both achieve higher secrecy rates than the equal power allocation scheme.
This paper investigates secrecy rate optimization for a multicasting network, in which a transmitter broadcasts the same information to multiple legitimate users in the presence of multiple eavesdroppers. In order to improve the achievable secrecy rates, private jammers are employed to generate interference to confuse the eavesdroppers. These private jammers charge the legitimate transmitter for their jamming services based on the amount of interference received at the eavesdroppers. Therefore, this secrecy rate maximization problem is formulated as a Stackelberg game, in which the private jammers and the transmitter are the leaders and the follower of the game, respectively. A fixed interference price scenario is considered first, in which a closed-form solution is derived for the optimal amount of interference generated by the jammers to maximize the revenue of the legitimate transmitter. Based on this solution, the Stackelberg equilibrium of the proposed game, at which both legitimate transmitter and the private jammers achieve their maximum revenues, is then derived. Simulation results are also provided to validate these theoretical derivations.
This paper investigates secrecy rate optimization for a multicasting network, in which a transmitter broadcasts the same information to multiple legitimate users in the presence of multiple eavesdroppers. In order to improve the achievable secrecy rates, private jammers are employed to generate interference to confuse the eavesdroppers. These private jammers charge the legitimate transmitter for their jamming services based on the amount of interference received at the eavesdroppers. Therefore, this secrecy rate maximization problem is formulated as a Stackelberg game, in which the private jammers and the transmitter are the leaders and the follower of the game, respectively. A fixed interference price scenario is considered first, in which a closed-form solution is derived for the optimal amount of interference generated by the jammers to maximize the revenue of the legitimate transmitter. Based on this solution, the Stackelberg equilibrium of the proposed game, at which both legitimate transmitter and the private jammers achieve their maximum revenues, is then derived. Simulation results are also provided to validate these theoretical derivations.
In this paper, secure transmission with simultaneous information and energy multicast in the presence of multiparty eavesdropper (EVE) collusion is investigated. In the considered system, legal users simultaneously decode information and harvest energy through dynamic power splitting (PS), whereas EVEs form multiple eavesdropping-collusion parties to cooperatively decode signals. A novel optimization problem is formulated to maximize the overall achievable secure multicast capacity while satisfying the maximum transmit power constraint at the transmitter, guaranteeing the minimum harvested energy requirements at each legal user and restricting the wiretapping capability of each EVE party. Since the formulated problem is nonconvex and hence difficult to solve, it is decomposed into a power minimization subproblem and a rate optimization subproblem and then solved in a nested manner. By leveraging the properties of the objective function, it is proved that through the proposed algorithm the optimal secure multicast capacity can be achieved, with the optimal transmission strategy, i.e., optimal beamforming matrix, optimal artificial noise (AN) covariance matrix, and optimal PS factors, obtained. Moreover, the case of imperfect channel state information (CSI) is considered in which a robust secure multicast scheme is designed by considering the channel uncertainty of EVEs and maximizing the worst-case achievable secure capacity. Simulation results confirm the optimality of the proposed algorithm, show its capability of adapting to the dynamic joining and departure of multicast users and EVE parties, and verify its superiority over existing schemes for both the perfect CSI and imperfect CSI cases.
Abstract:Physical-layer security has become a critical technique in current wireless networks.The existing conventional physical layer security techniques,e.g. artificial-noise-aided transmit beamforming,do not apply well to multicast transmission from large multicast user and eavesdropper user numbers.To address this problem,an enhanced secure multicast algorithm based on user clustering scheme was proposed.Firstly,the multicast users with close channel vectors were divided into a cluster and different clusters were served on different channels.Secondly,a heuristic joint power allocation and beamforming design algorithm based on this user clustering scheme were proposed to maximize the globally achievable secure multicast rate.Finally,to reduce the overall computation complexity,the new searching method was put forward to solve power allocation and beamforming design jointly.Simulation results showed that the enhanced secure multicast algorithm can support a much higher secure transmission rate than conventional secure multicast (CSM) schemes,and the proposed joint power allocation and beamforming design algorithm outperform existing CSM schemes with the ergodic searching method greatly in terms of computation complexity.