Satellite Link Adaptation via RF Intermediary Power Control
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Solution Overview
Problem
Conventional satellite communication systems face challenges in maintaining efficient operation due to RF disturbances like rain fade, antenna beam pointing errors, and Doppler effects, which affect signal attenuation and power efficiency in geosynchronous and non-geosynchronous satellite systems, as the satellite acts as an intermediary between user terminals and the satellite access network.
Innovation Solution
The method involves determining a set of operating parameters for reverse-link communications to achieve a target power efficiency based on the user terminal's location within the satellite's footprint, and dynamically adjusting these parameters to compensate for channel conditions in the service and feeder links, while maintaining the satellite's power efficiency, using a satellite access network with processors and memory to execute instructions for selecting reference locations and adjusting operating parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional link adaptation schemes are used where transmitting device directly communicates with receiving device, then signal attenuation can be compensated by adjusting transmission parameters, but satellite power efficiency cannot be optimized because the satellite's RF intermediary role is not considered
Solution Approach 1:
The patent introduces the satellite as an RF intermediary element in the link adaptation process. The satellite access network determines operating parameters for reverse-link communications by considering the satellite's RF characteristics and power efficiency targets, rather than treating the satellite as a transparent relay. This intermediary approach allows the system to optimize both signal transmission reliability and satellite power efficiency simultaneously.
Solution Approach 2:
The patent dynamically adjusts transmission parameters (such as modulation and coding scheme, transmit power) based on channel conditions in the service link and feeder link, while constraining the satellite's received signal power to maintain target power efficiency. This parameter adaptation resolves the contradiction by allowing reliable communication through parameter optimization while preventing excessive power consumption at the satellite.
2Reliability
If link adaptation dynamically adjusts transmission parameters to compensate for RF disturbances, then communication reliability improves, but system complexity increases due to additional control mechanisms
Solution Approach 1:
The patent implements feedback mechanisms where the satellite access network monitors channel conditions in both the service link (between user terminal and satellite) and the feeder link (between satellite and ground network). Based on this feedback, the system dynamically adjusts operating parameters to maintain communication reliability while managing complexity through structured feedback loops rather than ad-hoc control mechanisms.
Solution Approach 2:
The patent performs preliminary determination of operating parameters at the satellite access network before transmissions occur. By pre-calculating appropriate transmission parameters based on predicted channel conditions and satellite power efficiency targets, the system reduces the need for complex real-time adjustments during actual communication, thereby improving reliability while managing system complexity.
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 optimizes reverse-link communications by adapting to channel conditions, ensuring efficient satellite operation and maintaining target power efficiency despite RF disturbances, thereby enhancing communication reliability and performance.
Implementation Method 1
A conventional 'bent pipe' satellite may perform frequency conversion and power amplification when retransmitting a received communication signal
Implementation Method 2
A conventional 'bent pipe' satellite may perform frequency conversion and power amplification when retransmitting a received communication signal
Implementation Method 3
Rain fade, antenna beam pointing errors, line-of-sight blockage, Doppler effects, and other sources of RF disturbance may cause signal attenuation in the feeder link and/or service link
Implementation Method 4
Rain fade, antenna beam pointing errors, line-of-sight blockage, Doppler effects, and other sources of RF disturbance may cause signal attenuation in the feeder link and/or service link
Data Source
AI summary
A method and apparatus for link adaptation in a satellite communication system, wherein a satellite is configured to receive reverse-link (RL) communications from a user terminal (UT) via a service link and retransmit the RL communications to a satellite access network (SAN) via a feeder link. The SAN may select a reference location for the UT within a footprint of the satellite, and determine a set of operating parameters for the RL communications to achieve a target power efficiency of the satellite based on the reference location. The SAN may dynamically adjust one or more of the operating parameters, while maintaining the target power efficiency of the satellite, based at least in part on channel conditions in at least one of the service link, the feeder link, or a combination thereof. Among other advantages, the method disclosed herein may optimize RL communications based on the capabilities of the satellite.