Aircraft In-Flight Cellular Beam Steering and Doppler Compensation

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Solution Overview

Problem

Conventional air-to-ground communication technologies for airborne cellular communications rely on third-party services for initial positioning, leading to complex business models, energy inefficiencies, and high costs, as well as the need for continuous beam coverage to ensure connectivity, which is not only expensive but also inefficient.

Innovation Solution

A terrestrial cellular telecommunications system that uses aircraft navigation broadcast information to precisely steer beams and compensate for Doppler shifts, allowing for seamless coverage without relying on third-party services, by periodically acquiring aircraft navigation data to establish and maintain links, and performing beam steering and Doppler shift compensation based on the aircraft's position, altitude, and velocity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional air-to-ground communication technologies are used, then connectivity can be established, but reliance on third-party services increases device complexity and operational costs

Engineering Contradiction:
ImproveconnectivityVSAvoidreliance on third-party services
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system enables self-service by having the aircraft's own navigation broadcast receiver provide positioning information directly to the terrestrial network operator, eliminating the need for third-party positioning services. The aircraft autonomously provides its position, altitude, and velocity data through standard navigation broadcasts, allowing the operator to independently manage the communication link without external service providers.

Inventive Principle:
Principle #25Self-service

2Reliability

If continuous beam coverage is maintained to ensure connectivity, then service reliability improves, but energy consumption and operational costs increase

Engineering Contradiction:
Improveservice connectivityVSAvoidbeam activation energy
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary action by using the aircraft's navigation broadcast receiver to acquire position, altitude, and velocity information before establishing the communication link. This advance knowledge of the aircraft's trajectory allows the terrestrial network operator to predict when the aircraft will enter and exit coverage areas, enabling beam activation only when needed rather than continuously, thus reducing energy consumption while maintaining connectivity reliability.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If beams are activated in all directions to allow aircraft identification, then network accessibility improves, but energy efficiency deteriorates

Engineering Contradiction:
Improvenetwork accessibilityVSAvoidbeam activation energy
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The system applies dynamics by transitioning from static omnidirectional beam activation to dynamic directional beam steering based on real-time aircraft position data. The terrestrial network operator uses the navigation broadcast information to dynamically adjust beam directions, activating beams only in the specific directions where aircraft are present. This dynamic adaptation maintains network accessibility while dramatically reducing energy loss from unnecessary omnidirectional transmission.

Inventive Principle:
Principle #15Dynamics

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 solution reduces reliance on third-party services, minimizes energy consumption by only activating beams when necessary, and provides seamless coverage over a wide geographic area, increasing capacity by allowing more precise beamforming and sharing of spectral resources, thus reducing costs and improving service efficiency.

Implementation Method 1

a beam towards the first aircraft is directed to establish a first link between the first network node and the user equipment

Methodology Applied
Scientific EffectBeam steering:

Implementation Method 2

Doppler shift compensation is based on one or more determinations of relative velocity between the first aircraft and one or more first antenna nodes associated with the first network node, and compensates for a Doppler shift experienced by the user equipment

Methodology Applied
Scientific EffectDoppler shift compensation: Doppler Effect

Data Source

PatentEP3371899B1In-flight cellular communications system coverage of mobile communications equipment located in aircraft
Publication Date: 2021.04.28 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3371899B1 patent drawingFigure 1
  • EP3371899B1 patent drawingFigure 2~3
  • EP3371899B1 patent drawingFigure 4

AI summary

A network node of a terrestrial cellular system provides telecommunications service to a user equipment (UE) in an airborne aircraft. Navigation information transmitted from the aircraft is periodically acquired, including aircraft identity, position, altitude, and a time of determining aircraft position. A link is maintained between the network node and the UE by transmitting beam steered, Doppler shift compensated downlink signals, and by performing beam steered reception of uplink signals. Beam steering is directed toward the aircraft based on the navigation information. Doppler shift compensation is adapted to compensate for a Doppler shift such that the UE experiences a nominal carrier frequency when receiving transmissions from the antenna nodes. Handover from a first to a second coverage area includes using a same cell identifier and a same frequency allocation in the second coverage area as are used in the first.