Combined Open and Closed Loop Power Control in Satellite Relay Networks
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Solution Overview
Problem
In satellite relay-based wireless communication, existing power control methods fail to effectively mitigate signal impediments such as fading and interference across varying propagation conditions, especially when the terrestrial terminal is in motion, leading to unreliable communication without excessive power application.
Innovation Solution
A method and system combining open loop and closed loop power control components, where the open loop uses measurements of fading at a first terminal to adjust transmit power, and the closed loop uses measurements of fading at a second terminal with an acknowledgement message for power correction, incorporating speed estimation to address both short-term and long-term effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power control is applied to mitigate signal fading and interference in satellite relay communication, then communication reliability is improved, but system complexity increases due to the need for both open loop and closed loop control mechanisms
Solution Approach 1:
The power control system is divided into two independent segments: open loop power control that uses measurements at the first terminal to adjust transmit power for long-term fading, and closed loop power control that uses measurements at the second terminal with acknowledgement messages for short-term fading. This segmentation allows each component to address specific aspects of power control without requiring the full system complexity of a unified approach.
Solution Approach 2:
The open loop power control component performs preliminary power adjustment based on fading measurements at the first terminal before signal transmission. This preliminary action compensates for long-term fading effects in advance, reducing the burden on the closed loop component and enabling more efficient overall power control with reduced system complexity.
2Reliability
If satellite relay applies more power to overcome propagation impediments, then signal delivery reliability is improved, but power budget restrictions are violated
Solution Approach 1:
The open loop power control performs preliminary power adjustment at the first terminal based on fading measurements before transmission. This advance compensation for long-term fading effects ensures that the satellite relay receives signals with adequate power headroom, eliminating the need for the satellite to apply excessive power and thus respecting power budget restrictions while maintaining reliable signal delivery.
Solution Approach 2:
The closed loop power control component uses acknowledgement messages containing power correction information from the second terminal to provide feedback on short-term fading conditions. This feedback mechanism enables precise, minimal power adjustments at the satellite relay level, ensuring adequate signal delivery reliability without unnecessary power application that would violate power budget constraints.
3Speed
If closed loop power control is used alone to address short-term fading, then rapid power adjustment is achieved, but long-term fading effects are not adequately mitigated
Solution Approach 1:
The power control functionality is segmented into two distinct components: the open loop component handles long-term fading mitigation using measurements at the first terminal, while the closed loop component handles rapid short-term fading adjustment using measurements at the second terminal. This segmentation allows each component to specialize in its respective time scale without compromising the other's effectiveness.
Solution Approach 2:
The system merges the open loop and closed loop power control components into a unified power control mechanism. The open loop component addresses long-term fading with slower adjustments, while the closed loop component addresses short-term fading with rapid adjustments. Together, they provide comprehensive power control that achieves both rapid response to short-term conditions and adequate mitigation of long-term fading effects.
4Reliability
If open loop power control adjusts transmit power based on first terminal measurements, then long-term fading is compensated, but rapid short-term fading variations are not addressed
Solution Approach 1:
The power control system is segmented into two functional components operating at different time scales: the open loop component using measurements at the first terminal responds to long-term fading variations with slower power adjustments, while the closed loop component using measurements at the second terminal responds to rapid short-term fading variations with faster power adjustments. This segmentation enables each component to optimize its performance for its specific time scale without interfering with the other.
Solution Approach 2:
The system combines the open loop and closed loop power control components into an integrated power control solution. The open loop component provides baseline power adjustment for long-term fading compensation, while the closed loop component provides rapid superimposed adjustments for short-term fading. The merging of these components creates a comprehensive power control system that simultaneously achieves both long-term fading compensation and rapid response to short-term variations.
Data Source
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AI summary
In a telecommunication network where a wireless path is provided between a transmitter and a receiver via a satellite relay forming a multi-hop relayed signal path, a method and system are provided for furnishing adequate signal at a user terminal, which may be in motion, along the propagation path, the method including an open loop component that uses measurements of fading in a received signal at a first terminal to adjust transmit power from the first terminal and further includes a closed loop component that uses measurements of fading in the received signal at a second terminal along with an acknowledgement message and power correction.