This paper studies the secure transmission issue for simultaneous wireless information and power transfer (SWIPT) in a multiuser system with multiple eavesdroppers, where the base station transmitter broadcasts confidential message to legitimate multiple single-antenna information receivers (IRs) and multiple single-antenna energy-harvesting receivers (ERs). Our objective is to optimize the information bearing beam and artificial energy-carrying noise beam in order to maximize the secrecy rate of the IRs subject to individual harvested energy constraints of the ERs for the case where the ERs can form eavesdropping party to carry out joint decoding in an attempt to illicitly decode the secret message intended for the IRs. The initial non-convex problem is converted to convex problem through semi-definite programming (SDP) relaxation for both perfect CSI and imperfect CSI. Numerical simulations are presented to demonstrate the performance.
This paper studies the secure transmission issue for simultaneous wireless information and power transfer (SWIPT) in a multiuser system with multiple eavesdroppers, where the base station transmitter broadcasts confidential message to legitimate multiple single-antenna information receivers (IRs) and multiple single-antenna energy-harvesting receivers (ERs). Our objective is to optimize the information bearing beam and artificial energy-carrying noise beam in order to maximize the secrecy rate of the IRs subject to individual harvested energy constraints of the ERs for the case where the ERs can form eavesdropping party to carry out joint decoding in an attempt to illicitly decode the secret message intended for the IRs. The initial non-convex problem is converted to convex problem through semi-definite programming (SDP) relaxation for both perfect CSI and imperfect CSI. Numerical simulations are presented to demonstrate the performance.
This paper considers simultaneous wireless information and power transfer (SWIPT) in multiple-input single-output (MISO) downlink systems in which a multi-antenna transmitter sends a secret message to a single-antenna information receiver (IR) and power to multiple single-antenna energy receivers (ERs) in presence of external eavesdroppers. We aim to maximize the harvested energy by the ERs while maintaining the signal-to-interference and noise ratio (SINR) threshold at the IR and keeping the message secure from possible eavesdropping by the malicious attackers by interfering their reception. Both scenarios of perfect and imperfect channel state information (CSI) at the transmitter are studied. Using semidefinite relaxation (SDR) techniques, we show that a rank-one optimal beamforming solution can always be constructed for the IR.
This paper studies the secure transmission issue for simultaneous wireless information and power transfer in a multiuser multiple-input-multiple-output system with multiple external eavesdroppers, where the transmitter broadcasts independent confidential messages to different legitimate receivers. Each receiver can be seen as an internal eavesdropper intended by other receivers. Our objective is to achieve the robust beamforming design under imperfect channel state information, in which the total transmission power is minimized with constraints on the achievable secrecy rate and the energy harvesting. Since the problem is nonconvex, we propose a two-level optimization scheme. For the inner problem, we investigate two conservative relaxation approaches, large-deviation inequality and Bernstein-type inequality (BTI), to reformulate the outage secrecy rate constraints into some convex ones, yielding a convex optimization by semidefinite programming (SDP) relaxation. For the outer problem, it is a K-variable optimization problem, which can be solved via the novel line-dimensional-like search method. Moreover, we characterize the rank profile of SDP relaxed solution for these two approaches. Specifically, the optimal solution is proved to be rank-one. Numerical results are provided to verify the performance of the proposed algorithms, where the LDI-based scheme outperforms the BTI-based scheme in terms of energy efficiency.
Considering simultaneous wireless information and power transfer (SWIPT), we study a multiple-input- single-output (MISO) secrecy channel which consists of a multi-antenna trans- mitter and a cooperative jammer (CJ), multiple multi-antenna energy receivers (ERs), i.e., potential eavesdroppers, and multiple single-antenna co-located receivers (CRs). Both transmitter and CJ send the intend signal with artificial noise (AN) and jamming signal to interfere with the ERs. All receivers (CRs and ERs) adopt a power splitter to decode information and harvest power simultaneously. We exploit AN and CJ to facilitate efficient wireless energy transfer and secure transmission. Our aim is to maximize the minimum harvested energy among all ERs and CRs subject to the total power constraints at the transmitter and CJ while guaranteeing the minimum secrecy rate for each CR above its requirement. By incorporating norm-bounded channel uncertainty model, we propose a joint design of robust secure transmission. The original problem is solved by a two- step approach. In the first step, the proposed problem is reformulated as a sequence of semidefinite programs (SDPs). In the second step, the proposed problem can be handled by one-dimensional search to attain the optimal solution. Simulation results indicate that the performance of the proposed scheme outperforms that of separated AN-aided or CJ-aided scheme.
In this paper, we investigate multiple-input single-output (MISO) simultaneous wireless information and power transfer (SWIPT) broadcast channels with confidential messages (BCC) scenario, in which a multiple-antenna transmitter simultaneously transmits confidential messages and power to multiple single-antenna receivers. Considering the imperfect channel state information (CSI), we study the joint optimization of transmit beamforming vectors, covariance of artificial noise, and power splitting ratios so as to minimize the total transmit power while satisfying the worst-case conservative secrecy rate and energy harvesting constraints. The original optimization is non-convex and intractable in general. To handle this challenge, in this paper, we first derive the exact upper or lower bounds of the constraints in original optimization problem by using the Lagrangian approach, and then convert the corresponding non-convex problem into a convex one with the aid of the rank relaxation technique. Finally, we provide simulation results to illustrate the robustness of the proposed design.
In this paper, we design a secure transmission scheme for multiple-input single-output (MISO) broadcast channel with simultaneous wireless information and power transfer (SWIPT), where a multi-antenna transmitter simultaneously transmit independent confidential messages to multiple potentially malicious receivers, in the presence of external eavesdroppers. Our objective is to minimize the total transmit power while guaranteeing the security communication and energy harvesting constraints by jointly optimizing the transmit beamforming vectors, covariance of artificial noise, and power splitting ratios, which is non-convex optimization and hard to tackle. We first solve this non-convex problem by using the technique of semi-definite relaxation (SDR), and then prove that the relaxation is tight and thus achieves the globally optimal solution of the original problem. Simulation results are finally presented to demonstrate the performance of our proposed scheme.
This paper studies the secure beamforming design for simultaneous wireless information and power transfer in a multiple-input single-output broadcast channel with confidential messages and external eavesdroppers, where each receiver adopts the power splitting (PS) scheme to decode information and harvest energy concurrently, and it is also seen as a potential eavesdropper for messages not intended for it. Our objective is to minimize the total transmit power while guaranteeing the individual secrecy rate and energy harvesting constraints at each receiver by jointly optimizing transmit beamforming vectors, artificial noise covariance, and receive PS ratios. Both scenarios of perfect and imperfect channel state information (CSI) at the transmitter are considered. For the perfect CSI case, we propose a two-stage optimization approach to solve the original non-convex problem global optimality, and also provide a low-complexity suboptimal solution based on the particle swarm optimization algorithm. Furthermore, we also extend the above result to the colluding eavesdroppers scenario. For the imperfect CSI case, we propose a worst-case-based robust formulation, where the CSI errors are norm-bounded. With the aid of S-Procedure, we derive the equivalent forms for constraints and then transform the non-convex robust design into a convex optimization problem. Simulation results are finally presented to demonstrate the performance of our proposed schemes.