Airborne Cellular Coverage via Coordinated Beamforming
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Solution Overview
Problem
Current in-flight communication systems, both ground-based and satellite-based, fail to provide adequate data rates and capacity due to limitations in channel capacity, latency, and cost, especially in line-of-sight environments where traditional pilot sequences and MIMO techniques are ineffective.
Innovation Solution
A ground-based coordination method utilizing multiple terrestrial cellular network nodes to steer beam-formed, Doppler shift-compensated downlink signals, ensuring temporal delay alignment and mutual compatibility of signals transmitted to airborne devices, thereby increasing data rates through spatial diversity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional pilot sequences and MIMO techniques are used in line-of-sight airborne communications, then channel capacity is limited, but implementing new techniques increases system complexity
Solution Approach 1:
The patent segments the transmission into multiple layers, with different node groups transmitting different layers to the airborne device. This segmentation enables spatial diversity in line-of-sight conditions while maintaining manageable system complexity through structured coordination.
Solution Approach 2:
The patent introduces spatial dimensionality by utilizing multiple ground-based nodes positioned at different locations to transmit signals to the airborne device. This dimensional approach creates spatial diversity that overcomes the limitations of traditional single-node MIMO in line-of-sight airborne communications.
2Power
If beamforming with multiple antenna elements is implemented to increase signal gain, then antenna gain increases proportionally to 10*log(N), but the coordination complexity between multiple nodes increases
Solution Approach 1:
The patent merges the functions of multiple ground-based nodes into a coordinated beamforming system. Each node applies beamforming with its antenna array, and the master coordination node synchronizes their transmissions to create constructive interference at the airborne device, achieving combined gain while managing complexity through centralized coordination.
Solution Approach 2:
The system implements feedback mechanisms where the airborne device reports channel state information and the master coordination node adjusts beamforming parameters and timing for each node group. This feedback loop enables dynamic optimization of antenna gain while maintaining coordination efficiency.
3Productivity
If multiple node groups transmit simultaneously to increase data rates, then spatial diversity is achieved, but temporal delay alignment becomes critical
Solution Approach 1:
The master coordination node performs preliminary calculations to determine the exact timing offsets each node group must apply based on their geometric positions relative to the airborne device. This preliminary timing alignment ensures that signals from multiple node groups arrive synchronously at the receiver, enabling spatial diversity without inter-symbol interference.
Solution Approach 2:
The system dynamically adjusts transmission parameters including timing offsets, beamforming weights, and power levels for each node group based on real-time channel conditions and airborne device position. These parameter changes maintain temporal alignment and optimize data rates as the airborne device moves through different locations.
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 significantly enhances data rates and capacity for airborne communication devices by coordinating multiple ground-based nodes to transmit spatially diverse signals, overcoming the limitations of existing systems and providing efficient, affordable connectivity.
Implementation Method 1
By using arrays, it is possible to focus the transmitted energy in a beam in a specific direction in space
Implementation Method 2
MIMO principles allow construction of an independent data stream from a linear combination of signals from all transmitter antenna ports by controlling the phase and amplitude of each antenna port's output so as to cause each of the received signals to contribute constructively at the UE
Implementation Method 3
controlling Doppler shift pre-compensation performed by each of the groups of subordinate nodes such that the mobile communication equipment aboard the aircraft experiences a nominal carrier frequency
Implementation Method 4
coordinating timing of transmissions from the groups of subordinate nodes so as to have signals received by the mobile communication equipment from the groups of subordinate nodes keep within a required temporal delay of a cyclic prefix in the received signals
Data Source
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AI summary
Telecommunications service is provided to mobile equipment aboard an airborne aircraft. A master coordination node (MCN) coordinates communication from groups of subordinate nodes in the network such that each group communicates a different layer of data to the mobile communication equipment aboard the aircraft. Each group of subordinate nodes transmits beam steered, Doppler shift compensated downlink signals directed at the aircraft. Coordination controls the timing of transmissions from the subordinate nodes so as to have signals received by the mobile communication equipment from the groups of subordinate nodes keep within a required temporal delay of a cyclic prefix in the received signals; the Doppler shift pre-compensation performed by each subordinate node such that the mobile communication equipment aboard the aircraft experiences a nominal carrier frequency when receiving transmissions from each of the subordinate nodes; and ensuring mutual compatibility of the signals transmitted by each of the groups of subordinate nodes.