Dual-Antenna Uplink Selection for LEO Satellite Terminals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In non-terrestrial networks (NTN) like those using Low Earth Orbit (LEO) satellites, terminal devices face significant challenges with uplink transmissions due to extreme operating link loss and varying antenna gains, leading to inefficient battery consumption and connectivity issues.
Innovation Solution
The terminal device employs two types of antennas: a link antenna for data transfer and a monitoring antenna for receiving, using algorithms to determine optimal antenna switching based on path loss, satellite ephemeris, and location to manage uplink transmissions effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single antenna is used for both uplink transmission and downlink reception, then device complexity is reduced, but reliability of uplink communication deteriorates due to extreme path loss and varying antenna gains in NTN environments
Solution Approach 1:
The patent segments the antenna system into two distinct functional components: a link antenna optimized for uplink transmission with higher gain in the upward direction, and a monitoring antenna optimized for downlink reception. This segmentation allows each antenna to be specialized for its specific function, improving overall system reliability in NTN environments where path loss varies significantly with elevation angle.
Solution Approach 2:
The patent applies local quality by configuring the link antenna with specific radiation characteristics optimized for upward transmission toward satellites, while the monitoring antenna has radiation characteristics optimized for receiving downlink signals. Each antenna location in the system has different quality characteristics matched to its specific operational requirements.
2Device complexity
If the link antenna is used for monitoring in addition to data transfer, then device complexity is reduced, but battery consumption increases due to unnecessary transmissions when path loss is high
Solution Approach 1:
The patent extracts the monitoring function from the link antenna and assigns it to the dedicated monitoring antenna. This allows the link antenna to be used exclusively for uplink data transmission, and the monitoring antenna to handle downlink signal monitoring, preventing unnecessary battery consumption from attempting uplink transmissions when conditions are unfavorable.
Solution Approach 2:
The monitoring antenna provides continuous feedback about downlink signal quality and satellite visibility. This feedback enables the system to make informed decisions about when to initiate uplink transmissions, avoiding battery consumption on transmissions that are likely to fail due to extreme path loss or blocked visibility.
3Reliability
If antenna switching is performed frequently to optimize performance, then uplink communication reliability is improved, but device complexity increases due to switching control requirements
Solution Approach 1:
The patent implements preliminary action by using the monitoring antenna to continuously assess satellite visibility and downlink signal quality before initiating uplink transmissions. This advance monitoring allows the system to determine optimal transmission windows without requiring complex real-time switching decisions during transmission attempts.
Solution Approach 2:
The patent applies dynamics by enabling flexible switching between link and monitoring antenna functions based on real-time satellite visibility and signal conditions. The system dynamically adapts antenna usage to current operational requirements, optimizing uplink transmission reliability while managing device complexity through condition-based switching.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A method comprising securing orientation of a first type of an antenna and a second type of an antenna, wherein the first type of an antenna and the second type of an antenna are comprised in a terminal device, determining if the terminal device is radio resource control connected to a cell provided by an access node comprised, at least partly, in a satellite or relayed through the satellite, and if it is, estimating a link loss based, at least partly, on downlink receive measurements obtained using the first type of an antenna, determining an uplink link budget based on the estimated link loss, determining if the uplink link budget is greater than a threshold for a transmit antenna, wherein the transmit antenna is the first type of the antenna or the second type of an antenna, and attempting a transmission to the access node using the transmit antenna if the uplink link budget is greater than the threshold for the transmission antenna.