Drone network system for disaster-resistant connectivity

Abstract

A disaster-resistant network system consisting of a base station, a fleet of unmanned aerial vehicles each with a reconfigurable intelligent surface, and a controller, the controller being configured to adjust the reflection phase and amplitude of each element to direct incoming radio signals to target receivers and to decode navigation commands from the radio signals to control the propulsion for positioning the unmanned aerial vehicles to maintain coverage.

Description

Application area of ​​the invention

[0001] The invention relates to wireless communication by means of unmanned aerial vehicles equipped with reconfigurable intelligent surfaces for restoring or extending the range, wherein RIS / IRS metasurfaces adjust the phase, amplitude and direction of incident radio waves to generate controllable reflection paths. Background of the invention

[0002] Reconfigurable intelligent surfaces (RIS) are programmable metasurfaces with numerous passive reflective elements. Phase shifts allow for radio channel reconfiguration, enabling energy-efficient range extension and blockage resolution without active amplification. Integrating RIS into UAVs creates mobile, line-of-sight-based relay platforms for emergency and 6G scenarios. These support environmentally friendly, low-noise coverage by jointly optimizing RIS phase and UAV position / trajectory to maximize throughput and reliability during outages. Studies and reviews report improvements in range, energy efficiency, and secure transmission for IRS-enabled UAV networks, highlighting feasibility and design challenges, including channel estimation, rapid alignment, and the limited power of UAVs. Summary of the invention

[0003] The invention relates to a disaster-resistant network system comprising: a fleet of UAVs, each equipped with a smart reflective surface unit (RIS); a base station or donor node transmitting wireless signals; and a control unit that aligns the RIS metasurface by adjusting the reflection phase, amplitude, and direction for optimal reception at covert users or relay nodes. The control unit decodes navigation commands contained in the downlink control, controls the UAV motors for controlled flight, and manages dynamic RIS configurations to establish robust relay links that form an ad-hoc backhaul / fronthaul.

[0004] In some embodiments, the system establishes instant communication by positioning RIS-UAVs to ensure a virtual line of sight around obstacles. The RIS phase states are coordinated with the UAV position and the base station beam to maximize received signal quality in the target zones. The control loop tracks channel state information (CSI) or beacons to refine phase profiles and waypoint trajectories. Detailed description

[0005] Each UAV platform includes flight avionics, propulsion, navigation sensors (GNSS / IMU), a radio for communication with the base station, and a RIS unit with an integrated controller. The RIS consists of a two-dimensional array of programmable reflector elements over a ground plane. The controller sets phase and amplitude vectors for each element based on CSI to align the reflected beams with peak demand. A compact radio / processing module demodulates control signals and performs sub-second RIS configuration updates.

[0006] The control unit coordinates fleet deployment and the orientation of individual UAVs. It receives broadcast parameters from base stations and channel queries from field stations, calculates the reflection directions of the targets, and adjusts the UAVs' heading, altitude, and RIS phase matrices accordingly. Through joint optimization, UAV position and RIS configuration are aligned to maximize signal-to-noise ratio (SNR), total rate, or coverage, taking into account power and flight limitations.

[0007] To overcome dynamic obstacles, the system performs a closed-loop alignment control by utilizing pilot signals and feedback from user devices (UEs) or portable gateways and updating the RIS states to maintain constructive addition at the receivers while suppressing interference. Polarization-dependent control can be employed to further improve link performance.

[0008] The drone network forms a multi-hop mesh: A donor base station illuminates RIS UAVs, which reflect the light towards shielded areas or to other RIS UAVs, thus creating temporary corridors. If required, a drone can also carry an edge computing / MEC module to bridge heterogeneous radio links. Security includes authenticated control channels and protection against spoofing for RIS commands.

[0009] Navigation decoding utilizes a control channel embedded in the transmitter signal or a side link. The drone demodulates the navigation commands, verifies their integrity, and controls motors via electronic speed controllers (ESCs) to reach predefined waypoints and hover patterns while adhering to RIS orientation restrictions. Failover mechanisms include returning to the starting point and hovering in case of signal loss.

[0010] Considerations regarding performance and endurance include optimized RIS element counts, lightweight Metasurface panels, and energy-efficient flight paths. The RIS is passive and has very low power consumption; only the controller requires a moderate amount of energy, which improves flight time compared to active relays.

[0011] In an emergency, after a disaster has damaged ground infrastructure, UAV RIS units launch, align themselves with a donor base station, and reflect beams into obscured areas. Orientation and route are continuously updated to maintain operation. As ground infrastructure is gradually restored, the system is shut down.

Claims

[1] A disaster-resistant network system consisting of a base station, a fleet of unmanned aerial vehicles each with a reconfigurable intelligent surface and a controller, wherein the controller is configured to adjust the reflection phase and amplitude of each element to direct incoming radio signals to target receivers and to decode navigation commands from the radio signals to control the propulsion to position the unmanned aerial vehicles to maintain coverage. [2] System according to claim 1, wherein the control system jointly optimizes the position of the unmanned aerial vehicle and the parameters of the intelligent surface reflection based on channel state information to maximize the received signal quality for covert users while minimizing interference. [3] System according to claim 1, wherein several unmanned aerial vehicles cooperate to form a multi-stage reflective path between the base station and the users, the intelligent surface orientation being updated per stage in response to beacons or feedback from user devices. [4] System according to claim 1, wherein the intelligent reflective surface comprises a metasurface array over a ground plane with a control circuit that individually controls reflection units to adjust phase and amplitude in a software-controlled manner.