Dynamic HAPS Feeder-Link Antenna Positioning for Signal Separation
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Solution Overview
Problem
The communication quality deteriorates due to an instantaneous increase in propagation spatial correlation between feeder links in an aerial-floating type communication relay apparatus when the upper-airspace relay apparatus rotates and moves, leading to difficulties in separating signals and increased interference.
Innovation Solution
A communication relay apparatus with plural antennas for feeder links that adjusts its positional relationship based on a correlation index value, allowing for interference suppression by changing the placement distances and angles of the antennas, and switching between active and spare antennas to manage spatial correlation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beamforming of plural antennas for feeder link is performed when the upper-airspace relay apparatus rotates and moves, then the FB ratio (forward/backward gain of directional beam) is lowered, but the propagation spatial correlation between feeder links increases instantaneously, making it difficult to separate signals and deteriorating communication quality
Solution Approach 1:
The patent applies dynamics by making the antenna configuration changeable rather than fixed. The control unit dynamically adjusts the positional relationships of multiple antennas based on real-time correlation index values, allowing the system to adapt to varying propagation conditions during HAPS rotation and movement, thereby preventing instantaneous increase in spatial correlation and maintaining signal separation capability
Solution Approach 2:
The patent changes physical parameters by modifying the positional relationships (placement distances and angles) of antennas in the feeder link. When the correlation index exceeds a threshold, the control unit changes at least one placement distance or placement angle of the antennas, fundamentally altering the spatial configuration to reduce propagation spatial correlation and improve communication quality
2Adaptability or versatility
If the upper-airspace relay apparatus rotates and moves in the upper airspace, then the FB ratio is lowered, but it becomes difficult to separate signals transmitted and received by each feeder link
Solution Approach 1:
The patent implements feedback by using the correlation index value as real-time feedback to control antenna configuration. The control unit continuously monitors the correlation index and adjusts antenna positional relationships based on this feedback, creating a closed-loop system that maintains signal separation capability while allowing HAPS rotation and movement
Solution Approach 2:
The system transitions from a static antenna configuration to a dynamic one where antenna positions are continuously adjusted based on operational conditions. This dynamic reconfiguration allows the system to maintain adaptability to HAPS movement while preserving signal separation capability through real-time positional adjustments
Data Source
AI summary
It is to prevent a deterioration of communication quality due to an instantaneous increase in a propagation spatial correlation between plural feeder links between plural antennas for feeder link (FL antennas) incorporated in an aerial-floating type communication relay apparatus (HAPS) and plural gateway (GW) stations. The aerial-staying type communication relay apparatus (HAPS) comprises a feeder-link communication section that transmits and receives relay signals different from each other at a same frequency in the feeder links between the communication relay apparatus and plural GW stations that are time-synchronized with each other, an interference suppression section that suppresses interferences between the plural feeder links formed between the communication relay apparatus and the plural GW stations, means for obtaining correlation index values (SINRs, singular values or eigenvalues) indicating respective degrees of propagation spatial correlation of the plural feeder links, and means for changing a mutual positional relationship between the plural antennas for feeder link, based on a comparison result between the correlation index values and a predetermined threshold value.