Air-to-Ground Beam Steering for Interference Reduction
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Solution Overview
Problem
Current technologies for in-flight broadband connectivity using wide beams for air-to-ground communication suffer from interference and capacity issues due to scattering, leading to degraded performance and inter-carrier interference, especially when terrestrial frequencies are reused for backhaul links.
Innovation Solution
The implementation of Flight Transceiver Stations (FTS) equipped with large antenna arrays capable of beam steering, using Automatic Dependent Surveillance-Broadcast (ADS-B OUT) for precise location tracking and Doppler shift compensation, to direct narrow beams towards terrestrial transceiver points, thereby minimizing interference and maximizing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If wide beams are used for uplink transmissions from aircraft to ground equipment, then coverage area is improved, but interference for terrestrial UEs increases and uplink performance deteriorates
Solution Approach 1:
The patent applies local quality by transitioning from uniform wide beam coverage to localized narrow beam targeting. Each beam is precisely directed at specific ground equipment locations based on aircraft position and ground equipment databases, concentrating energy where needed while minimizing interference in other areas. This resolves the contradiction by making beam characteristics location-dependent rather than uniform.
Solution Approach 2:
The patent changes the beam parameter from wide to narrow based on real-time conditions. By using aircraft navigational information (position, orientation, velocity) and ground equipment location data, the system dynamically adjusts beam width and direction. This parameter change allows the system to achieve both adequate coverage and reduced interference by adapting beam characteristics to specific spatial contexts.
2Area of stationary object
If wide beams are used for uplink transmission, then coverage is improved, but time dispersion and frequency dispersion increase due to signal scattering
Solution Approach 1:
The patent improves signal quality by replacing wide scattered beams with localized narrow beams targeted at specific ground equipment. This localization reduces the propagation paths and reflecting surfaces involved, thereby minimizing scattering-induced time and frequency dispersion while maintaining coverage through systematic beam steering across multiple positions.
Solution Approach 2:
The system performs preliminary action by pre-acquiring ground equipment location information and aircraft navigational data to calculate optimal beam directions before transmission. This advance preparation enables precise beam targeting that prevents scattering from occurring in the first place, thereby maintaining signal integrity and reducing dispersion effects.
3Productivity
If the same set of beams serves multiple aircraft or physical resources are reserved for terrestrial UEs, then resource efficiency is improved, but inter-carrier interference increases without orthogonality maintenance
Solution Approach 1:
The patent implements feedback mechanisms where the system continuously monitors aircraft positions, beam directions, and signal conditions. Based on this feedback, it dynamically adjusts beam parameters and resource allocation to maintain orthogonality between signals from different aircraft or between aerial and terrestrial users. This real-time feedback enables efficient resource sharing while preventing inter-carrier interference through active coordination.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces interference and enhances capacity by using narrow beams that are precisely directed, maintaining orthogonality between signals and allowing for efficient handover operations, even when multiple aircraft share the same physical resources.
Implementation Method 1
The implementation of Flight Transceiver Stations (FTS) equipped with large antenna arrays capable of beam steering
Implementation Method 2
using Automatic Dependent Surveillance-Broadcast (ADS-B OUT) for precise location tracking and Doppler shift compensation
Data Source
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AI summary
A flight transceiver station (FTS 400) mounted onboard an aircraft communicates with one or more terrestrial transceiver points (TTPs) by determining (901, 903, 905, 907), for a future moment in time t, a position of the flight transceiver station in 3 -dimensional space; an attitude of the flight transceiver station; one or more respective directions from the position of the flight transceiver station to the one or more terrestrial transceiver points; respective radial velocities between the flight transceiver station and the one or more terrestrial transceiver points. The FTS 400 also determines (911), based on the respective directions and attitudes, beamforming weights for one or more transmit beams towards each of the one or more terrestrial transceiver points; and predicts (913), based on the respective radial velocities, respective Doppler shifts of a carrier frequency used between the flight transceiver station and the one or more terrestrial transceiver points. The beamforming weights for the one or more transmit beams, and a Doppler pre-compensation based on the predicted Doppler shifts are applied (919) to transmitter equipment of the flight transceiver station, at the future moment in time t.