Gradual Frequency Adjustment for NTN Uplink Interference
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Solution Overview
Problem
Current wireless communication systems, particularly in non-terrestrial networks (NTNs), face challenges in managing frequency adjustments for user equipment (UE) due to rapid changes in location and velocity, leading to frequency misalignment and interference in uplink transmissions.
Innovation Solution
A method where user equipment (UE) and non-terrestrial network (NTN) nodes implement frequency pre-compensation (FPC) commands to adjust uplink transmissions based on current location and velocity updates, ensuring the total FPC adjustment satisfies threshold requirements, thereby minimizing frequency phase shifts and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequent FPC commands are transmitted to rapidly moving UEs in NTN, then frequency alignment accuracy is improved, but signaling overhead and system complexity increase
Solution Approach 1:
The patent applies preliminary action by having the network pre-configure threshold parameters (e.g., frequency offset thresholds, velocity thresholds) in advance. The UE uses these pre-configured thresholds to determine when FPC commands are needed, avoiding the need for continuous frequent signaling. This resolves the contradiction by maintaining frequency alignment accuracy through threshold-based triggering while reducing system complexity by eliminating continuous monitoring and signaling overhead.
2Reliability
If gradual FPC adjustment is implemented based on threshold comparisons, then frequency misalignment is reduced, but adjustment time and latency increase
Solution Approach 1:
The patent implements dynamics by making the FPC adjustment rate adaptive rather than fixed. The adjustment granularity and timing are dynamically adjusted based on the comparison between current frequency offset and pre-configured thresholds. When the offset exceeds the threshold, more aggressive adjustments are made; when within thresholds, adjustments are gradual or paused. This resolves the contradiction by ensuring frequency alignment reliability through threshold-based control while minimizing adjustment time through adaptive response.
Solution Approach 2:
The patent applies parameter changes by modifying the FPC adjustment parameters (such as adjustment step size and timing) based on the current system state and threshold comparisons. The network can change parameters like the threshold values themselves, the adjustment granularity, and the timing of commands based on UE velocity, location updates, and frequency offset measurements. This resolves the contradiction by optimizing both alignment reliability and adjustment time through dynamic parameter adaptation.
3Measurement precision
If FPC commands are transmitted at every location update, then frequency tracking accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent applies local quality by implementing differentiated FPC command transmission based on local conditions. Instead of uniform transmission at every location update, the system transmits FPC commands selectively based on local factors such as whether the frequency offset exceeds thresholds, the UE's velocity characteristics, and the importance of the upcoming transmission. This resolves the contradiction by maintaining frequency tracking accuracy for critical transmissions while reducing signaling overhead by avoiding unnecessary commands during stable conditions.
Data Source
AI summary
In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus at a UE in NTN are provided. The UE may be configured to receive one or more FPC commands from an NTN. The UE may be further configured to transmit, in response to receiving the one or more FPC commands, an uplink transmission with a frequency change having a total FPC adjustment calculated based on (a) a current UE location update and a current UE velocity update, wherein the total FPC adjustment satisfies one or more threshold requirements, or (b) an intermediary UE location update between the current UE location update and a previous UE location update and an intermediary UE velocity update between the current UE velocity update and a previous UE velocity update.