Non-terrestrial Network Link Adaptation via Fading Estimates
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Solution Overview
Problem
Non-terrestrial networks face challenges in determining appropriate signal transmission characteristics due to significant transmission delays and changing signal characteristics, making it difficult to adjust parameters for optimal communication quality between non-terrestrial stations and ground-based receivers.
Innovation Solution
A communication system that includes a non-terrestrial network station, user equipment, and a terrestrial base station, where the base station evaluates signal quality indications from the user equipment to adjust modulation and channel coding parameters, using estimates of shadow and fast fading losses to optimize signal transmission settings based on successful or unsuccessful receipt of signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If signal transmission is performed in non-terrestrial networks, then communication coverage is extended, but transmission delay increases significantly
Solution Approach 1:
The system performs preliminary actions by estimating shadow fading and fast fading characteristics before actual signal transmission. The base station calculates fading estimates based on historical data and current conditions, allowing the NTN station to pre-configure transmission parameters that account for expected delays and signal variations, thereby reducing the impact of transmission delay on communication quality.
Solution Approach 2:
The system implements dynamic adaptation by continuously adjusting transmission parameters based on real-time fading estimates and feedback. The base station modifies modulation and coding schemes dynamically in response to changing signal conditions, enabling the system to adapt to transmission delays and maintain optimal communication performance despite the inherent latency in non-terrestrial networks.
2Reliability
If transmission parameters are adjusted to improve signal quality, then communication reliability improves, but system complexity increases
Solution Approach 1:
The system employs feedback mechanisms where the base station receives indication information from user equipment about signal quality and transmission success. This feedback is used to refine fading estimates and adjust transmission parameters iteratively, improving communication reliability while keeping the control logic manageable through closed-loop adaptation rather than complex open-loop calculations.
Solution Approach 2:
The system manages complexity by focusing adjustments on key transmission parameters such as modulation order and coding rate, rather than optimizing all possible parameters simultaneously. The base station selects a subset of critical parameters to modify based on fading estimates, simplifying the parameter adjustment process while achieving significant improvements in communication reliability.
3Measurement precision
If signal transmission settings are optimized for current conditions, then signal quality improves, but adaptation speed decreases due to transmission delay
Solution Approach 1:
The system performs preliminary estimation of fading characteristics using historical data and current conditions before actual transmission occurs. By calculating shadow fading and fast fading estimates in advance, the base station can configure transmission parameters that account for expected signal variations, improving measurement precision while the preliminary nature of these calculations allows for timely parameter selection despite transmission delays.
Solution Approach 2:
The system applies partial adaptation by adjusting only the most critical transmission parameters based on fading estimates, rather than attempting to optimize all parameters simultaneously. This partial action approach improves signal quality through targeted parameter adjustment while reducing the computational burden and time required for complete parameter optimization, thereby maintaining acceptable adaptation speed.
Data Source
AI summary
Systems and methods for communication link adaptation and communication networks involving ground-based user equipment and non-terrestrial stations. A communication is received indicating signal quality of a first signal transmitted during a first transmission period and a plurality of fading losses associated with the first signal are obtained. A first fading loss and a second fading loss associated with the first signal are estimated for a future time, the first fading loss based on application of a first filter, and the second fading loss based on differences determined between the first fading loss and the plurality of fading losses. A signal-to-interference-plus-noise-ratio is calculated and includes at least one of the first fading loss and the second fading loss. A non-terrestrial station transmits, for a second time period, a second signal having settings determined based on the signal-to-interference-plus-noise-ratio.