HAPS Feeder Link Frequency Efficiency via MIMO
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Solution Overview
Problem
The communication capacity of the service link in aerial-floating type communication relay apparatuses is limited by the frequency efficiency of the feeder link, necessitating an improvement in frequency utilization efficiency to support increased demand.
Innovation Solution
Implementing a spatial-division multiplex communication system between the High-Altitude Platform Stations (HAPS) and multiple gateway stations, using MIMO interference cancellation techniques to eliminate interference and optimize frequency utilization, while adjusting antenna directional beams and weights to maintain communication quality despite HAPS movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spatial-division multiplex communication is implemented between HAPS and multiple gateway stations, then frequency utilization efficiency is improved, but interference between feeder links increases
Solution Approach 1:
The patent applies MIMO interference cancellation to convert the harmful interference between feeder links into a beneficial effect. By using multiple antennas at both the HAPS and gateway stations, the system receives both desired signals and interference signals, then applies signal processing to cancel the interference and extract the desired signals. This transforms the harmful multi-link interference into an opportunity to improve frequency utilization through spatial multiplexing.
Solution Approach 2:
The patent introduces spatial dimensionality to the communication system by deploying multiple gateway stations and using MIMO technology. Instead of using additional frequency resources for multiple links, the system exploits the spatial dimension with multiple antennas and spatial-division multiplexing, allowing simultaneous communication on the same frequency without traditional interference limitations.
2Reliability
If antenna directional beams are adjusted to track HAPS movement, then communication quality is maintained, but system complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the HAPS transmits beacon signals that gateway stations use to determine the HAPS position and adjust their beam directions accordingly. This closed-loop feedback system maintains communication quality by continuously tracking the moving HAPS while distributing the tracking complexity across multiple ground-based gateway stations rather than requiring complex active tracking on the HAPS itself.
Data Source
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AI summary
Provide a system capable of improving a frequency utilization efficiency of a feeder link of an aerial-floating type communication relay apparatus. A system, which has an aerial-staying type communication relay apparatus that wirelessly communicates with a terminal apparatus, is provided with plural gateway stations that perform space-division multiplexing communication for transmitting and receiving different relay signals from each other on a same frequency in a feeder link with the aerial-stay type communication relay apparatus. Each of the plural gateway stations may be provided with an antenna control section that controls an antenna for feeder link so as to track the aerial-stay type communication relay apparatus.