High Altitude Platform Modulation Coding Segmentation
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Solution Overview
Problem
Current telecommunications platforms face challenges in achieving high capacity and spectral efficiency, particularly in high-altitude platforms (HAPS) due to limitations in frequency resources and interference from gateway stations, which affects data rates and system capacity.
Innovation Solution
The system employs a processor to demodulate and decode feeder links, allowing for independent modulation and coding (MODCOD) modes between gateway and user links, enabling spectrally efficient modes for feeder links and robust modes for user links, and dynamically shares the 47 GHz band spectrum between gateway and user terminal links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If robust modulation and coding schemes are used for user terminal links to ensure reliability in noisy environments, then link robustness is improved, but spectral efficiency deteriorates
Solution Approach 1:
The patent segments the communication links into two distinct types: feeder links (gateway to platform) and user links (platform to user terminals). Each link type is assigned different modulation and coding schemes optimized for its specific requirements. Feeder links use spectrally efficient modes while user links use robust modes, resolving the contradiction by allowing each segment to operate independently with appropriate parameters.
Solution Approach 2:
The patent applies local quality by tailoring the modulation and coding scheme to the specific characteristics of each link type. Feeder links, which have better channel conditions, use high-order modulation (e.g., 64-QAM, 256-QAM) for maximum spectral efficiency. User links, which face fading and noise, use lower-order modulation (e.g., QPSK, 16-QAM) with stronger error correction for reliability. This localized optimization resolves the contradiction between robustness and spectral efficiency.
2Device complexity
If the same modulation and coding scheme is used for both feeder links and user links, then system complexity is reduced, but overall system capacity deteriorates
Solution Approach 1:
The patent divides the communication system into separate feeder link and user link components, each with independent modulation and coding scheme selection. This segmentation allows the system to optimize for both spectral efficiency (feeder links) and reliability (user links) simultaneously, maximizing overall capacity without requiring complex adaptive switching mechanisms.
Solution Approach 2:
The patent implements dynamic modulation and coding scheme selection based on link type and channel conditions. The system dynamically assigns appropriate MODCOD modes to different link types, allowing feeder links to operate at high spectral efficiency while user links maintain robustness. This dynamic adaptation enables the system to achieve high overall capacity without excessive complexity.
3Productivity
If more gateway stations are deployed to increase system capacity, then overall system capacity is improved, but the number of needed gateway stations increases
Solution Approach 1:
The patent changes the modulation and coding parameters for feeder links to achieve higher spectral efficiency. By using high-order modulation schemes (64-QAM, 256-QAM) and advanced error correction codes on feeder links, the system extracts more data rate from the same frequency resources. This parameter optimization increases the capacity contribution of each gateway station, reducing the total number needed to achieve a given system capacity target.
Data Source
AI summary
Modulation and coding for a high altitude platform is disclosed. An example method includes determining a first modulation scheme and a first coding scheme that is spectrally efficient for a feeder link communicatively coupled to a gateway antenna and determining a second modulation scheme and second coding scheme that is robust for user links communicatively coupled to respective user antennas. Each user antenna is configured to communicate with a specified cell within a specified area. The example method also includes provisioning the telecommunications apparatus with the first modulation scheme, the first coding scheme, the second modulation scheme, and the second coding scheme.