This paper proposes a novel communication scheme utilizing Simultaneously Transmitting and Reflecting Reconfigurable Intelligent Surface (STAR-RIS) and Index Modulation (IM) for Industrial Internet of Things (IIoT) to enhance Spectral Efficiency (SE). In this scheme, information bits are conveyed through the active antennas combination index of the two sensors at receiver, as well as the Pattern Index (PI) of designed subsurfaces on STAR-RIS. To enable reliable detection at the IIoT Control Center (CC), a joint Maximum Likelihood (ML) detector is introduced, and an Efficient ML Approximation (EMAL) detector is developed to lower computational complexity while retaining comparable Bit Error Rate (BER). In the theoretical analysis, closed-form expressions for the Average BER (ABER) under ML detection and computational complexity are provided, and the ABER analysis is validated by Monte Carlo simulations. Theoretical analysis and simulation results confirm that the proposed scheme significantly improves SE and ABER performance. Moreover, through simulation results, the scheme’s flexibility in configuring the number of antennas of the two sensors to meet diverse system requirements is also confirmed.

In this paper, we propose a novel polarized reconfigurable intelligent surface (PRIS) -assisted polarized spatial scattering modulation (PSSM) for millimeter wave (mmWave) multiple input multiple output (MIMO) systems. In the PRIS-PSSM system, the PRIS is employed between the transmitter and receiver to provide a supplementary link to enhance spectrum efficiency. A strong line-of-light (LoS) path is considered in the transmitter-PRIS channel to reduce transmission power and non-line-of-light (NLoS) paths are considered in the PRIS-receiver channel to utilize scatters to convey information bits. At the receiver, an optimal maximum likelihood detector (MLD), a sub-optimal MLD, and a low-complexity detector based on minimum mean square error (MMSE) algorithm are proposed and applied to detect the received signals. Furthermore, two union upper bounds (UUBs) based on the optimal MLD and sub-optimal MLD are respectively derived in a closed-form. And the tightness of the proposed two closed-form UUBs are validated via link level simulations. In addition, the complexity of the proposed three detection algorithms is compared. Numerical results demonstrate that the proposed PRIS-PSSM system outperforms the conventional PSSM system in terms of the average bit error probability (ABEP). And the performance of the PRIS-PSSM system can be improved significantly in proportion to the number of PRIS elements.

The integration of the Sixth-Generation (6G) communication technology with the Internet of Things (IoT) is one of the directions in achieving a digitalized world, aiming to provide ultra-high-speed communication services that exhibit higher energy-efficiency, lower latency, and heightened reliability and availability. In this paper, we investigate the use of the Simultaneous Transmitting and Reflecting Reconfigurable Intelligent Surface (STAR-RIS), one of the candidate technologies for 6G communication, along with the Index Modulation (IM) in multi-antennas Ambient Backscatter Communication System (ABCS) to form the STAR-RIS-assisted ABCS with Spatial Modulation (STAR-RIS-ABCS-SM). In particular, through the utilization of STAR-RIS and backscatter communication, we meet the demand for low-power wireless communication devices in the green communication, which is also a crucial characteristic of the IoT. Specifically, we introduce STAR-RIS into ABCS, which not only significantly boost the signal strength but also achieve full communication coverage. Meanwhile, we apply the SM technology in the multi-antennas Backscatter Tags (BTs), located on both sides of the STAR-RIS, and use joint detection at the reader to enhance the system’s Spectral Efficiency (SE) as well as its Bit Error Rate (BER) performance. Furthermore, we divide the STAR-RIS into various subsurfaces to form patterns that further enhance SE, which is termed STAR-RIS-assisted ABCS with Pattern Index and SM (STAR-RIS-ABCS-PISM) scheme. Finally, theoretical BER analytical expressions for both schemes are derived and presented. Simulation and theoretical results demonstrate the enhanced performance of the proposed schemes as well as the validity of the system model.

In this paper, a novel three-dimensional polarized spatial scattering modulation (3-D PSSM), which exploits the available degrees of freedom in the spatial scattering path domain and polarization domain to increase spectral efficiency, is proposed for uplink millimeter-wave (mmWave) multiple-input-multiple-output (MIMO) system. At the receiver, considering the non-orthogonality of the array vectors, a whitening filter based on optimal maximum likelihood detection (MLD) is designed and applied to detect received signals. A tight union upper bound (UUB) on the average bit error probability (ABEP) is derived in a closed-form. Furthermore, a simplified UUB on the ABEP is derived for fast evaluation of the system. And the tightness of the derived UUBs is validated via Monte Carlo simulations. In addition, the 3-D PSSM system under imperfect channel state information (CSI) is investigated. Finally, the ABEP performance of the 3-D PSSM is analyzed in typical indoor propagation environments. Numerical results demonstrate that the proposed 3-D PSSM system outperforms the conventional three-dimensional spatial scattering modulation (3-D SSM) system and the two-dimensional (2-D) PSSM system, which is considerably degraded due to indiscernible scattering paths.

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.

According to the Federal Aviation Administration (FAA), the number of Remotely Piloted Air Systems (RPASs), colloquially known as drones, will rapidly increase in the near future. Challenges with drones are focused not only on the security of these devices, but also on the criminal uses for drones which need to be carefully considered. Incident response and forensic analysis of such cases have not been sufficiently addressed by the research community. This paper focuses on incident response of cybercrimes related to drones as well as some possible anti-forensic techniques that could be used to alter digital evidence associated with drones. In addition, this paper also revisits the enacted regulations that purport to restrict the operation of drones in critical infrastructure areas. We evaluate drone incident response by exploring a case study using a hypothetical drone forensic tool to illustrate the acquisition of GPS metadata from both media files and flight logs, with a view towards aiding the incident responders and digital forensic investigators in analyzing illegal flight activities and report such incidents effectively.