This paper investigates the secure transmission in satellite communication systems, where a geostationary orbit (GEO) satellite serves an earth station while multiple eavesdroppers attempt to intercept the confidential message. Assuming that only the imperfect channel state information (CSI) of the wiretap channels are available, we propose a secure beamforming scheme to maximize the secrecy energy efficiency (SEE) of the earth station while satisfying the signal-noise-ratio (SNR) requirement at earth station, the secrecy constraints at eavesdroppers, and per-antenna power constraints at satellite antenna feeds. Since the formulated optimization problem is mathematically intractable, we propose a two-stage beamforming scheme to convert the original nonconvex problem into a solvable one and obtain the beamforming weight vectors. Numerical results are finally provided to verify the effectiveness of our proposed scheme.
This paper investigates the secure transmission in satellite communication systems, where a geostationary orbit (GEO) satellite serves an earth station while multiple eavesdroppers attempt to intercept the confidential message. Assuming that only the imperfect channel state information (CSI) of the wiretap channels are available, we propose a secure beamforming scheme to maximize the secrecy energy efficiency (SEE) of the earth station while satisfying the signal-noise-ratio (SNR) requirement at earth station, the secrecy constraints at eavesdroppers, and per-antenna power constraints at satellite antenna feeds. Since the formulated optimization problem is mathematically intractable, we propose a two-stage beamforming scheme to convert the original nonconvex problem into a solvable one and obtain the beamforming weight vectors. Numerical results are finally provided to verify the effectiveness of our proposed scheme.
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.
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.
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 article proposes a beamforming (BF) scheme for a cognitive satellite terrestrial network, where the base station (BS) and a cooperative terminal (CT) are exploited as green interference resources to enhance the system security performance in the presence of unknown eavesdroppers. Different from the related works, we assume that only imperfect channel information of the mobile user (MU) and earth station (ES) is available. Specifically, we formulate an optimization problem with the objective to degrade the possible wiretap channels within the private signal beampattern region, while imposing constraints on the signal-to-interference-plus-noise ratio (SINR) at the MU, the interference level of the ES and the total transmit power budget of the BS and CT. To solve this mathematically intractable problem, we propose a joint artificial noise generation and cooperative jamming BF scheme to suppress the interception. Finally, the effectiveness and superiority of the proposed BF scheme are confirmed through computer simulations.
This paper investigates the physical layer security of a satellite network, whose downlink spectral resource is shared with a terrestrial cellular network. We propose to employ a multi-antenna base station (BS) as a source of green interference to enhance secure transmission in the satellite network. By taking the mutual interference between these two networks into account, we first formulate a constrained optimization problem to maximize the instantaneous rate of the terrestrial user while satisfying the interference probability constraint of the satellite user. Then, with the assumption that imperfect channel state information (CSI) and statistical CSI of the link between the BS and satellite user are available at the BS, we present two beamforming (BF) schemes, namely, hybrid zero-forcing and partial zero-forcing to solve the optimization problem and obtain the BF weight vectors in a closed form. Moreover, we analyze the secrecy performance of primary satellite network by considering two practical scenarios, namely: Scenario I, the eavesdroppers CSI is unknown at the satellite and Scenario II, the eavesdroppers CSI is known at the satellite. Specifically, we derive the analytical expressions for the secrecy outage probability for Scenario I and the average secrecy rate for Scenario II. Finally, numerical results are provided to confirm the superiority of the proposed BF schemes and the validity of the performance analysis, as well as demonstrate the impacts of various parameters on the secrecy performance of the satellite network.