In this paper, we propose a robust secure communication scheme for a two-Unmanned Aerial Vehicle (UAV) scenario with the assistance of Intelligent Reflecting Surface (IRS), in which one legitimate user and one eavesdropper are considered. In the proposed scheme, the information is transmitted from one UAV named information UAV to the user via the assistance of the IRS, while the jamming information is transmitted by the other UAV named jamming UAV equipped with multi-antenna to interfere with the eavesdropper and safeguard the communication between information UAV and legitimate receiver. For the considered communication system, we assume that the Channel State Information (CSI) of the eavesdropping channels are imperfect. In this imperfect CSI case, we formulate a robust non-convex optimization problem. By jointly optimizing UAV transmit power, trajectory, and IRS phase shifters, the suboptimal average secrecy rate of the proposed scheme can be obtained. Specifically, Lagrangian dual transform and quaduratic transform are introduced to convert the objective function into more tractable form; S-Procedure is used for handling CSI uncertainty; and a two-stage penalty function algorithm is applied to obtain rank-one phase shifters solution. Numerical simulation results validate some interesting insights: (1) The IRS can bring strong robustness to the two-UAV security communication system; (2) Deploying jamming UAV in the IRS-UAV security communication system can greatly improve security performance, especially employing more antennas at the jamming UAV.

A joint selected strategy is proposed for wireless sensor networks to address the energy consumption problem in this letter. The proposed strategy saves energy by selecting the sensor and modulation constellation size. Results from simulations show that the proposed strategy obtains significant energy reduction compared with the existing strategy under the same environment.

In this letter, we propose a novel intelligent reflecting surface (IRS) aided receive generalized space shift keying (RGSSK) wireless communication scheme utilizing IRS reflection patterns to achieve high spectral efficiency transmission. In this scheme, additional bits are transmitted as a pattern information defined by the proposed group pattern strategy, while the IRS elements are divided for the RGSSK realization. Theoretical error performance is discussed with a joint maximum likelihood detector under the measurement of average bit error rate. Computer simulation results reveal the flexibility and reliability of this scheme with high spectral efficiency.

Due to the broadcasting characteristics of wireless channels, both jammers and eavesdroppers pose a serious threat to wireless communications. In this article, we propose a scheme using active reconfigurable intelligent surface (RIS) to assist secure communication and prevent simultaneous jamming and eavesdropping. In this scheme, we assume that the jammer only interferes with the legitimate user, due to the potential cooperation between the eavesdropper and the jammer. To maximize the secrecy rate, a design problem of joint optimization of base station beamforming, and amplification factor and phase shifts matrices at the active RIS is proposed. Due to the non-convexity and coupling variables of this problem, we propose to use alternating optimization and semidefinite relaxation techniques to solve this optimization problem. Simulation results show that active RIS leads to a higher system secrecy rate compared to existing schemes in the presence of both jamming and eavesdropping.