This letter proposes a robust beamforming (BF) scheme to enhance physical layer security (PLS) of the downlink of a multibeam satellite system in the presence of either uncoordinated or coordinated eavesdroppers (Eves). Specifically, with knowing only the approximate locations of the Eves, we aim at maximizing the worst-case achievable secrecy rate (ASR) of the legitimate user (LU), subject to the constraints of per-antenna transmit power and quality of service (QoS) requirement of the LU. Since the optimization problem is non-convex, we first adopt the discretization method to deal with the unknown regions of the Eves and then exploit the log-sum-exp function to approximate the objective function. Afterwards, a BF method joint alternating direction method of multipliers (ADMM) with Dinkelbach iteration is presented to solve this non-convex problem. Finally, simulation results verify that our robust BF algorithm can effectively improve the security of multibeam satellite systems.
This letter proposes a robust beamforming (BF) scheme to enhance physical layer security (PLS) of the downlink of a multibeam satellite system in the presence of either uncoordinated or coordinated eavesdroppers (Eves). Specifically, with knowing only the approximate locations of the Eves, we aim at maximizing the worst-case achievable secrecy rate (ASR) of the legitimate user (LU), subject to the constraints of per-antenna transmit power and quality of service (QoS) requirement of the LU. Since the optimization problem is non-convex, we first adopt the discretization method to deal with the unknown regions of the Eves and then exploit the log-sum-exp function to approximate the objective function. Afterwards, a BF method joint alternating direction method of multipliers (ADMM) with Dinkelbach iteration is presented to solve this non-convex problem. Finally, simulation results verify that our robust BF algorithm can effectively improve the security of multibeam satellite systems.
This paper investigates the physical layer security (PLS) of a multibeam satellite communication system where the satellite transmits the private signal to a legitimate user (LU) which is intercepted by multiple eavesdroppers (Eves). By considering the imperfect channel state information (CSI) of Eve channels, we formulate the constrained problem to maximize the LU achievable secrecy rate (ASR) subject to secrecy rate outage probability constraint, the total satellite transmit power constraint and the LU rate constraint. Firstly, we adopt golden section method to transform the difficult original problem into a series easier sub-problem. Then, considering the nonconvex of sub-problem, we employ Bernstein inequality and semidefinite programming (SDP) to transform the sub-problem into solvable one. Then, we use standard software package to get the optimal beamforming (BF) weight vector through an iterative penalty-based algorithm. Finally, simulation results confirm the superiority and robustness of the designed BF scheme.
This paper investigates the physical layer security in a multibeam satellite communication system, where each legitimate user is surrounded by one eavesdropper. First of all, an optimization problem is formulated to maximize the sum of achievable secrecy rate, while satisfying the on-board satellite transmit power constraint. Then, two transmit beamforming(BF) schemes, namely, the zero-forcing (ZF) and the signal-to-leakage-and-noise ratio (SLNR) BF algorithms are proposed to obtain the BF weight vectors as well as power allocation coefficients. Finally, simulation results are provided to verify the validity of the two proposed methods and demonstrate that the SLNR BF algorithm outperforms the ZF BF algorithm.
This letter investigates the secure transmission optimization in a multibeam satellite downlink network with multiple eavesdroppers, where each legitimate user is wiretapped by a corresponding eavesdropper. Our design objective is to maximize the sum secrecy rate of the multibeam satellite network in the presence of imperfect channel state information (CSI) of eavesdroppers, while guaranteeing the total transmit power constraint on-board the satellite. Due to the nonconvexity and intractability resulting from the eavesdroppers' CSI uncertainty, a robust beamforming scheme is proposed to transform the initial optimization problem into a convex framework by jointly applying the Taylor expansion, S-Procedure, and Cauchy-Schwarz inequality. Meanwhile, an iterative algorithm is introduced to obtain the optimal solution. Finally, the validity and superiority of the proposed scheme are confirmed through comparisons with the existing nonrobust and perfect CSI approaches.
In order to enhance the security of multi-beam satellite communication system with multiple eavesdroppers, under the condition of available statistical channel state information, two beamforming (BF) schemes respectively for minimizing the total transmit power and maximizing the secrecy rate were proposed. Firstly, an optimization problem was formulated to minimize the satellite total transmit power while satisfying the secrecy rate requirement, and the analytical expression of optimal BF weight vector was obtained by adopting the Lagrange multiplier method. Then, two optimization problems were established to maximize secrecy rate with the constraint of total transmit power and per-antenna power budget, respectively. For the total transmit power constraint, the analytic expression of optimal BF weight vector was obtained by using generalized Rayleigh quotient method. For the per-antenna power constraint, the non-convex problem was converted into a convex one by introducing auxiliary variable, and further an iterative golden section-based algorithm was proposed to obtain the optimal BF weight vectors. Finally, the simulation results confirmed the effectiveness and validity of the proposed BF schemes. Meanwhile, the effect of the system parameters on the security performance was also analyzed. Compared to the traditional BF schemes, the proposed three BF schemes can obtain better secrecy performance.
Compared with terrestrial communication, satellite communication has played a crucial role in 6G communication as a result of wide-area coverage characteristics. Among them, beamforming scheduling and information security are critical research issues to improve system transmission performance. However, in geostationary earth orbit (GEO)-based satellite communication systems, owing to the wide-area coverage, ground users are susceptible to inter-beam interference caused by multibeam antennas at the satellite, and the information received by terrestrial users may be eavesdropped by air or terrestrial eavesdroppers. To this end, in this article, we propose a new robust security transmission strategy by combining beamforming and artificial noise (AN) techniques. Specifically, based on the actual satellite communication network scenario, the uncertain channel models are formulated as bounded uncertainty sets by considering the impact of imperfect channel state information of both legitimate and wiretap channels. Then, we build a bounded-constrained beamforming optimization to maximize the sum rate of legitimate users, while guaranteeing the constraints of total transmit power on the satellite and the minimum security rate of each legitimate user. Since the original problem is non-convex and mathematically intractable, we jointly exploit the successive convex approximation, Taylor series expansion, S-Procedure, and the semi-definite relaxation approach, with which the original problem can be transformed into a tractable one with a series of linear matrix inequality constraints. Furthermore, we propose an iterative algorithm to obtain the optimal beamforming and AN vectors. Finally, simulation results show that, compared with the existing algorithms, the proposed algorithm has better security and robustness.
In this paper, we investigate the physical layer security of a full-duplex base station (BS)-aided system in the worst case, where an uplink transmitter (UT) and a downlink receiver (DR) are equipped with a single antenna, while a powerful eavesdropper is equipped with multiple antennas. For securing the confidentiality of signals transmitted from the BS and UT, an artificial noise (AN)-aided secrecy beamforming scheme is proposed, which is robust to the realistic imperfect state information of both the eavesdropping channel and the residual self-interference channel. Our objective function is that of maximizing the worst-case sum secrecy rate achieved by the BS and UT, through jointly optimizing the beamforming vector of the confidential signals and the transmit covariance matrix of the AN. However, the resulting optimization problem is non-convex and non-linear. In order to efficiently obtain the solution, we transform the non-convex problem into a sequence of convex problems by adopting the block coordinate descent algorithm. We invoke a linear matrix inequality for finding its Karush-Kuhn-Tucker (KKT) solution. In order to evaluate the achievable performance, the worst-case secrecy rate is analytically derived. Furthermore, we construct another secrecy transmission scheme using the projection matrix theory for performance comparison. Our simulation results show that the proposed robust secrecy transmission scheme achieves substantial secrecy performance gains, which verifies the efficiency of the proposed method.