Satellite Timing Tracking Test Framework for NTN Synchronization
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Solution Overview
Problem
In non-terrestrial networks, especially satellite communication systems, the large common delays and rapid delay variations due to high satellite speeds pose challenges for maintaining uplink synchronization, leading to significant overhead in physical layer resources.
Innovation Solution
A method is disclosed that involves setting common delays and ephemeris values for a base station, allowing it to communicate with user equipment using signals that simulate satellite communication paths. This method determines errors in timing between the user equipment and a reference point, enabling more accurate timing adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If legacy frequency tracking and corrections are used for LEO satellite communications, then the existing UE timing-keeping mechanisms can be maintained, but the rapid delay variations caused by ultra-high satellite speeds (approximately 7.5 kilometers/second) cannot be properly managed
Solution Approach 1:
The patent changes the timing parameters from legacy terrestrial network parameters to NTN-specific parameters including common delay values, ephemeris values, and updated timing advance mechanisms. This allows the system to adapt to the rapid delay variations caused by LEO satellite speeds while maintaining synchronization reliability through these specialized parameters.
Solution Approach 2:
The base station performs preliminary actions by setting common delays and ephemeris values before communication begins. These pre-configured values enable the UE to accurately track timing without requiring continuous corrections during the high-speed satellite movement, thus resolving the contradiction between adaptability and reliability.
2Measurement precision
If timing advance commands are generated frequently to maintain uplink synchronization in NTN, then timing accuracy can be maintained, but the amount of timing advance commands creates a massive overhead in the physical layer resources
Solution Approach 1:
The patent extracts the timing synchronization function from continuous UE-gNB interaction and relocates it to the base station through common delay and ephemeris value settings. This extraction reduces the frequency of timing advance commands needed from continuous to periodic updates, significantly reducing physical layer overhead while maintaining timing accuracy.
Solution Approach 2:
The system implements a feedback mechanism where the base station determines errors corresponding to timing between the UE and reference point, then uses this information to adjust common delays and ephemeris values. This closed-loop feedback enables accurate timing maintenance with reduced command frequency, resolving the contradiction between precision and overhead.
Data Source
AI summary
Common delay(s) are set for a base station, the base station and a UE able to communicate via signals and to use the common delay(s) in communication. The common delay(s) correspond to delay in communication of the signals in a path from a simulated satellite to a reference point, which is a point selected between the base station and the simulated satellite. The UE is placed in a known location. Ephemeris values are set for the base station for the simulated satellite and caused to be broadcasted toward the UE. The ephemeris values represent positioning of the simulated satellite through which the signals are supposed to travel. In response to communication over the path by the UE, error is determined corresponding to at least timing at least between the UE and the reference point.