Phase-Controlled Polarization for Stable Radio Relay Gain Control
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Solution Overview
Problem
In radio relay apparatuses positioned in upper airspace like drones or balloons, fluctuations in reception power due to attitude changes such as rotation or tilt make it difficult to control the gain of power amplifiers effectively, especially when using linear polarization antennas, leading to inconsistent signal transmission.
Innovation Solution
A communication system utilizing a base station with multiple linear polarization antennas and a phase control apparatus to combine radio waves into circular or elliptical polarization, allowing for precise gain control of power amplifiers in radio relay apparatuses based on reception power, even with attitude changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If linear polarization antennas are used for feeder link communication, then device size and weight are reduced, but reception power fluctuates due to attitude changes
Solution Approach 1:
The patent changes the polarization parameter of the transmitted signal from linear to circular/elliptical polarization by applying phase shifts (90 degrees) between orthogonal linear polarization antennas. This parameter change makes the signal reception insensitive to attitude changes while maintaining the use of linear polarization antennas, thus reducing weight while improving reception stability.
2Loss of energy
If linear polarization antennas are used, then internal loss is reduced, but reception power fluctuates with attitude changes
Solution Approach 1:
The patent applies a phase shift parameter change to convert linear polarization to circular/elliptical polarization in the transmitted signal. This allows the system to maintain low internal loss characteristics of linear polarization antennas while achieving attitude-insensitive reception through the modified signal polarization state.
3Device complexity
If only reception power of known signal is used for gain control, then control simplicity is maintained, but proper gain control becomes difficult with large polarization fluctuations
Solution Approach 1:
By changing the transmitted signal polarization to circular/elliptical through phase shifting, the patent eliminates large fluctuations in received power caused by attitude changes. This maintains the simplicity of using only known signal reception power for gain control while significantly improving the accuracy and reliability of the measurement.
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 stabilizes reception power and enables effective gain control of power amplifiers in radio relay apparatuses, ensuring consistent signal transmission despite attitude fluctuations, without the need for larger, heavier circular polarization antennas.
Implementation Method 1
a base-station processing section for controlling a phase difference between a plurality of transmission signals supplied to a plurality of linear polarization antennas, so that a combined polarization of radio waves of the known signal transmitted from the antenna apparatus to the radio relay apparatus becomes a circular polarization or an elliptical polarization
Data Source
AI summary
It is provided of a communication system capable of suppressing a fluctuation in a reception power of a known signal from a base station due to an attitude change of a radio relay apparatus, and performing an appropriate gain control of a power amplifier of the radio relay apparatus based on the reception power of the known signal, in case that the base station uses a plurality of linear polarization antennas for wireless communication with the radio relay apparatus. The base station comprises an antenna apparatus that has a plurality of linear polarization antennas capable of transmitting and receiving radio waves with different angles of linear polarization planes from each other when performing a feeder-link communication with the radio relay apparatus, and a base-station processing section or an externally-attached phase control apparatus for controlling a phase difference between plural transmission signals supplied to the plurality of the linear polarization antennas, so that a combined polarization of radio waves of the known signal transmitted from the antenna apparatus to the radio relay apparatus becomes a circular polarization or an elliptical polarization, with respect to a predetermined time slot for transmitting to the radio relay apparatus a specific known signal usable for gain control of a power amplifier of the radio relay apparatus.