Closed-Loop Timing and Frequency Corrections for NTN Preambles

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Solution Overview

Problem

In non-terrestrial networks, existing techniques for time and frequency adjustments during random access procedures in wireless communications systems result in errors due to frequent location changes of user equipment (UE) and network entities, leading to reception problems and inefficiencies.

Innovation Solution

The UE maintains or improves preamble reception performance by using a preamble-specific time or frequency adjustment based on network indications rather than resetting adjustments to zero, accumulating adjustments from the network, or using a control message for specific adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the UE resets the time or frequency adjustment to zero for each preamble transmission, then the random access procedure can be performed independently, but preamble reception performance deteriorates due to frequent location changes in non-terrestrial networks

Engineering Contradiction:

Improveindependence of random access procedureVSAvoidpreamble reception performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The network entity provides timing or frequency adjustment indications to the UE before the UE transmits the preamble. These preliminary adjustments account for the UE's location and the non-terrestrial network entity's position, allowing the UE to compensate for location changes before transmission occurs, thereby improving preamble reception performance while maintaining procedural independence

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The network entity provides feedback in the form of timing or frequency adjustment indications based on the UE's location information and the non-terrestrial network entity's position. This feedback loop allows the UE to continuously refine its adjustments, maintaining reliable preamble reception despite frequent location changes in the non-terrestrial environment

Inventive Principle:

Principle #23Feedback

2Reliability

If the UE uses accumulated time or frequency adjustments from network indications, then preamble reception performance is improved, but the complexity of managing adjustments increases

Engineering Contradiction:

Improvepreamble reception performanceVSAvoidadjustment management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The timing or frequency adjustment indications provided by the network entity serve multiple functions: they correct for location changes, maintain synchronization, and enable accurate preamble transmission. By using a single adjustment mechanism for multiple purposes, the patent reduces the complexity of managing separate adjustment systems while maintaining improved preamble reception performance

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12414163B2Closed loop time and frequency corrections in non-terrestrial networks

Publication Date: 2025.09.09 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communications are described. Described techniques provide for mitigating error in time or frequency adjustments for preambles of a random access procedure. A user equipment may use one value for the adjustment when transmitting data to a non-terrestrial network, but then transmit the preamble of a random access procedure according to a preamble-specific time or frequency adjustment based on one or more indications received from the network (e.g., rather than resetting the adjustment to “0”). By using some signaled value for the preamble-specific timing or frequency adjustment rather than resetting the adjustment to “0,” preamble reception performance may be maintained or improved with as many or fewer position measurements for the UE or non-terrestrial network entity.