Beamforming Matrix Angular Difference Calculation for Satellite Switching
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Solution Overview
Problem
In non-terrestrial networks, wireless devices face challenges in accurately determining the position of satellites and efficiently switching between satellite beams due to high path loss and interference, especially when using de-facto standard TLEs for ephemeris data, which degrades over time and lacks precise directional information for antenna pointing.
Innovation Solution
A method using beamforming matrices to direct radio beams from an antenna array to satellites, determining angular differences between satellites to configure updated beamforming matrices for communication, and employing ephemeris data to refine beam directions, even when the antenna plane orientation is unknown, allowing for efficient satellite switching and reduced search spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TLE ephemeris data is used for satellite positioning, then satellite position can be determined, but the data degrades over time and lacks precise directional information for antenna pointing
Solution Approach 1:
The patent segments the ephemeris data into two parts: TLE data for basic satellite position determination and additional directional parameters (azimuth and elevation angles) for precise antenna pointing. This segmentation allows each data component to serve its specific purpose without the limitations of using TLE alone for both positioning and directional information.
Solution Approach 2:
The patent introduces an intermediary calculation process that uses the satellite position from TLE data combined with the device position to compute azimuth and elevation angles. This intermediary step transforms the limited TLE information into comprehensive directional guidance for beamforming, bridging the gap between basic positioning and precise pointing requirements.
2Area of stationary object
If wide beams are used to cover large areas in NTN, then coverage area is increased, but intercell interference increases significantly
Solution Approach 1:
The patent applies local quality by directing highly directional beams precisely to specific satellite positions based on calculated azimuth and elevation angles. Instead of using wide uniform beams, each beam is locally optimized to cover only the necessary area, thereby maintaining coverage while minimizing interference to adjacent cells.
Solution Approach 2:
The patent changes the beam parameters dynamically by calculating specific azimuth and elevation angles for each satellite and adjusting the beamforming weights accordingly. This parameter adjustment allows the system to maintain narrow, focused beams that provide adequate coverage while significantly reducing intercell interference compared to fixed wide beams.
3Reliability
If directional antennas are used to overcome path loss, then communication reliability is improved, but the system requires precise knowledge of satellite position and beam direction
Solution Approach 1:
The patent implements self-service by enabling the wireless device to autonomously calculate its own beamforming parameters. The device uses its known position and received satellite ephemeris data to compute azimuth and elevation angles, then determines the appropriate beamforming weights without requiring complex network assistance or pre-configured directional information.
Solution Approach 2:
The patent replaces complex mechanical or network-based position determination systems with a computational approach. Instead of requiring complex hardware or network-provided directional data, the system substitutes mathematical calculations based on simple position inputs and ephemeris data to generate precise beamforming parameters, reducing overall system complexity.
4Adaptability or versatility
If the UE searches for satellites over the entire sky, then all possible satellites can be found, but the search time and complexity increase significantly
Solution Approach 1:
The patent applies preliminary action by having the network provide ephemeris data to the UE in advance. This allows the UE to pre-calculate satellite positions and determine the angular differences before actual satellite acquisition begins, significantly reducing the search time while maintaining comprehensive satellite coverage.
Solution Approach 2:
The patent transforms the three-dimensional sky search problem into a simplified angular difference calculation by using the known device position and satellite ephemeris data. This dimensional reduction allows the UE to calculate precise beam directions using azimuth and elevation angles derived from positional information, rather than performing exhaustive three-dimensional sky scanning.
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 enables accurate satellite positioning and efficient beam switching, improving communication reliability and reducing interference by precisely directing radio beams, even in line-of-sight conditions, thereby enhancing connectivity in non-terrestrial networks.
Implementation Method 1
The wireless device employs a first beamforming matrix for directing a radio beam from an antenna array to a first satellite
Data Source
AI summary
The invention refers to a method performed by a wireless device (10), for connecting to a second satellite (20b) in a non-terrestrial network, NTN, wherein the wireless device employs a first beamforming matrix for directing a radio beam from an antenna array of the wireless device to the a first satellite (20a), the method comprising determining an angular difference between the directions towards the first and the second satellite, determining a second beamforming matrix, for communication with the second satellite, based on a direction of the beam towards the first satellite and the determined difference in angles, and using the second beamforming matrix to configure a receiver and/or transmitter for connecting to the second satellite; the invention further refers to corresponding method performed by a network node comprising transmitting to the wireless device ephemeris data of the first and the second satellite order to allow the wireless device determining an angular difference between the directions towards the first and the second satellite; the invention further refers to a corresponding wireless device (10) and to a corresponding network node.