UE Communication Parameter Estimation in Non-Terrestrial Networks
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Solution Overview
Problem
Existing solutions for estimating communication link parameters in user equipment (UE) for non-terrestrial networks (NTN) rely on Global Navigation Satellite Systems (GNSS), which increase cost and complexity and take a long time to establish initial access, especially for low-cost UEs.
Innovation Solution
A method in the UE estimates communication parameters like Timing Advance (TA) and Doppler pre-compensation by determining the propagation time difference of reference signals from a single satellite-based access node, eliminating the need for a GNSS receiver and reducing the time required for initial access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS receiver is used to estimate UE position for communication parameter estimation, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces an intermediary approach by using reference signal propagation time measurements as a mediator to estimate UE position indirectly, rather than directly using GNSS receiver hardware. The propagation time difference of reference signals from the satellite-based access node serves as the intermediary measurement that enables communication parameter estimation without requiring complex GNSS equipment.
Solution Approach 2:
The patent replaces the mechanical/GNSS-based positioning system with an electromagnetic signal-based approach. Instead of using GNSS receiver hardware that requires complex mechanical and electronic components, the solution substitutes it with a simpler system that measures propagation time of reference signals, thereby eliminating the need for complex positioning hardware while maintaining estimation accuracy.
2Measurement precision
If GNSS receiver is used to determine UE position, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent applies preliminary action by having the satellite-based access node transmit reference signals before the UE needs to establish communication. The UE can continuously or periodically measure propagation time of these pre-transmitted reference signals, so that when initial access is needed, the position estimation is already available or can be quickly derived, eliminating the time-consuming GNSS acquisition process.
Solution Approach 2:
The patent enables the UE to skip the lengthy GNSS signal acquisition and processing steps by using the alternative propagation time measurement method. The UE can rush through the initial access procedure with a simplified position estimation based on reference signal timing, achieving faster connection establishment without sacrificing the necessary measurement precision for communication parameter calculation.
3Measurement precision
If multiple access nodes are used for parameter estimation, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the essential measurement requirement from the complex multi-node scenario and identifies that a single satellite-based access node is sufficient for obtaining the necessary propagation time information. By taking out only the critical element (reference signal propagation time from one node) rather than requiring measurements from multiple nodes, the solution maintains measurement precision while significantly reducing signal processing complexity.
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 reduces technical complexity and cost by not requiring a GNSS receiver and shortens the time for initial access to NTN, allowing for faster connection establishment without relying on multiple access nodes.
Implementation Method 1
a reference signal which is transmitted with a predetermined period from the access node
Implementation Method 2
calculating a value of the parameter based on a position which satisfies a spatial condition for the UE, which spatial condition is given by a propagation time difference of the reference signal between said occasions
Data Source
AI summary
A method carried out in a UE (1) for estimation of a parameter of a communication link, such as Timing Advance, for use in communication with an orbiting satellite-based access node (141) of a non-terrestrial network (130). The method comprises determining, at repeated occasions, a time of reception (Tk) in the UE of a reference signal which is transmitted with a predetermined period (τP) from the access node. A value of the parameter is calculated based on a position (51,52) which satisfies a spatial condition for the UE, which spatial condition is given by a propagationtime difference (Δk) of the reference signal between said occasions (Tk, Tk+1).