4G User Terminal Positioning Validation via Satellite and Base Station Channel Measurements
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Solution Overview
Problem
Current 4G communication systems using satellite networks face challenges in accurately verifying the geographical position of user terminals due to large satellite cell sizes and limited coverage, leading to unreliable GNSS position measurements, which affects routing, billing, and legal interception, especially in geostationary deployments with wide cells and low accuracy in LEO/MEO satellite constellations.
Innovation Solution
A method that involves determining and validating the position of a 4G user terminal by exchanging first positioning data via satellite and second positioning data based on propagation channel measurements from proximity base stations, with the central network comparing these data sets to authenticate and secure the user terminal's position, using secret keys calculated from channel measurements to ensure accurate positioning and secure communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS coordinates are used for positioning in satellite networks, then the user terminal can determine its position, but the position data can be easily altered and is not reliable for network verification
Solution Approach 1:
The patent implements a feedback mechanism where the network sends reference signals to the user terminal, which measures propagation channel characteristics and returns them to the network. The network then verifies these measurements against expected values, creating a closed-loop validation system that ensures position data authenticity while maintaining high precision.
2Reliability
If conventional positioning techniques are used in terrestrial networks, then positioning can be verified, but satellite cells are very large and geographical areas are not necessarily covered by multiple cells simultaneously
Solution Approach 1:
The patent segments the positioning verification process into multiple independent measurements of propagation channel characteristics (delay, Doppler shift, angle of arrival) that can be performed independently of cell boundaries. This allows reliable position verification even when a user terminal is covered by only one satellite cell, as the multiple measurement parameters provide sufficient constraints for accurate positioning.
3Measurement precision
If new pilots are introduced on service links for positioning, then positioning reference signals can be used, but the solution is difficult to implement if only one satellite is available and/or only one NTN cell covers the service area
Solution Approach 1:
The patent makes the propagation channel measurement approach universal by designing it to work with any satellite constellation configuration (one or multiple satellites, one or multiple NTN cells). The same measurement principles apply regardless of the specific network deployment, eliminating the need for complex implementation variations and making the solution broadly applicable across different satellite network architectures.
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 method enhances the accuracy of user terminal positioning in 4G satellite networks, minimizing equipment impact and improving reliability for billing, routing, and legal interception, while securing the communication link using electromagnetic fingerprints.
Implementation Method 1
secondary positioning data based on all or part of the propagation channel measurements performed by the user terminal on the proximity base stations
Implementation Method 2
third positioning data based on propagation channel measurements performed by the proximity base stations on the user terminal
Implementation Method 3
the second positioning data is compared with the third positioning data within the 4G core network. The first positioning data from the user terminal is validated if the second positioning data is compatible with the third positioning data
Data Source
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AI summary
The invention relates to a 4G communication system comprising a 4G cellular radio network, each cell of said 4G cellular radio network comprising at least one base station, each base station being adapted to communicate with a 4G-compatible user terminal (UE). The communication system comprises a satellite (Sat), said satellite (Sat) being adapted to exchange service frames (TS) with the user terminal (UE), a gateway (GW), said gateway (GW) being adapted to exchange feeder link frames (TLF) with the satellite (Sat), a 4G core network (CN), said 4G core network (CN) being connected to the gateway (GW), said core network (CN) being capable of communicating with the base stations. The user terminal (UE) is capable of communicating at any given time with several base stations, referred to as proximity base stations (eNB1, ..., eNBi, ..., eNBn).