Satellite Terminal Power Control with Multi-Frequency Interference Compensation
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Solution Overview
Problem
Existing Ka band satellite communication systems fail to effectively compensate for co-channel and co/cross-polarization interference across multiple frequencies, leading to uneven noise and interference levels that vary with frequency, which affects signal quality and power control accuracy.
Innovation Solution
Implementing a method that performs multi-frequency ranging to derive specific power settings for each frequency, using a Long Term Filter (LTF) to track slow variations in noise and interference, and a System Tracking Filter (STF) for fast changes, allowing for continuous power control adjustments to maintain signal quality targets across all frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single nominal transmit power level is used across all frequencies based on flat noise and interference assumption, then system complexity is reduced and ease of operation is improved, but signal quality and power control accuracy deteriorate due to frequency-specific interference variations
Solution Approach 1:
The patent divides the single power control system into multiple frequency-specific power control mechanisms. Each frequency receives dedicated power control adjustments based on its specific interference conditions, implemented through per-frequency ranging power settings and interference compensation values that are independently calculated and applied to different inroute frequencies
Solution Approach 2:
The patent applies different power control strategies to different frequency segments based on their local interference characteristics. Each frequency receives customized power adjustments tailored to its specific interference environment, rather than applying a uniform power control approach across all frequencies
2Measurement precision
If multi-frequency ranging is performed to derive frequency-specific power settings, then power control accuracy is improved, but device complexity and measurement time increase
Solution Approach 1:
The patent performs multi-frequency ranging measurements during the initial setup phase to establish frequency-specific power settings before normal operation begins. This preliminary characterization of each frequency's interference environment allows the system to operate with high accuracy without requiring complex real-time measurements during data transmission
Solution Approach 2:
The patent implements continuous feedback mechanisms where the satellite gateway monitors signal quality indicators for each frequency and sends power control adjustments back to the satellite terminal. This closed-loop feedback system automatically adapts to changing interference conditions without requiring manual reconfiguration or complex real-time measurements
3Reliability
If continuous power control adjustments are made for each frequency, then signal quality is maintained under varying conditions, but processing time and system complexity increase
Solution Approach 1:
The patent implements periodic power control updates rather than continuous adjustments for each frequency. The system performs ranging measurements and interference compensation calculations at scheduled intervals, updating power settings periodically to maintain signal quality without requiring constant processing
Solution Approach 2:
The patent employs dynamic power control where adjustment frequency and granularity are adapted based on current conditions. During stable conditions, updates occur less frequently, while during rapidly changing interference conditions, the system increases the frequency of power control adjustments to maintain signal quality
Data Source
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AI summary
A method and a satellite terminal are provided. The satellite terminal may range over multiple frequencies and may receive, from a satellite gateway, a signal quality indicator with respect to each of the ranged multiple frequencies. Noise and interference for a corresponding frequency are estimated based on at least one of the received signal quality indicators for the corresponding frequency. Path loss is estimated based on multiple received signal quality indicators, each of which is received in response to the satellite terminal transmitting a signal while not performing the ranging process. A transmit power level of the satellite terminal is adjusted for the corresponding frequency based on the estimated path loss and the estimated noise and interference for the corresponding frequency.