NTN Uplink Scheduling With K_offset for RTT Delays

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Solution Overview

Problem

In non-terrestrial networks (NTN) with high satellite altitudes, the long round trip time (RTT) results in excessively long timing advance (TA), leading to delayed downlink receptions and challenges in uplink transmission scheduling.

Innovation Solution

Implementing a time domain location offset (K_offset) for uplink transmissions, signaled at various levels such as cell, beam, or UE-specific, to adjust the timing of uplink resources, using system information, MAC-CE, DCI, or RRC configurations, and combining these signals to reduce overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If timing advance (TA) is applied to compensate for long RTT in NTN, then uplink transmission timing is adjusted, but downlink reception is delayed and may occur in the past

Engineering Contradiction:

ImproveRTT delayVSAvoiddownlink reception timing

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent applies a time domain location offset (K_offset) that is added to the timing advance calculation. This offset is determined in advance based on satellite ephemeris information and is applied before the actual transmission timing calculation, allowing the system to pre-compensate for the excessive TA caused by long RTT and prevent downlink reception from occurring in the past

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent modifies the timing parameter by introducing K_offset as an additional parameter in the timing calculation formula. This parameter changes the effective timing advance value, adjusting it to be appropriate for NTN conditions where standard TA would be excessive, thereby resolving the timing mismatch between uplink transmission and downlink reception

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If K_offset is signaled at multiple levels (cell, beam, UE-specific), then timing accuracy is improved, but signaling overhead increases

Engineering Contradiction:

Improvetiming accuracyVSAvoidsignaling overhead

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent segments the K_offset signaling into multiple levels: cell-level common K_offset, beam-level K_offset, and UE-specific K_offset. This segmentation allows the system to apply different granularity of timing adjustments where needed while using coarser adjustments elsewhere, improving timing accuracy for specific UEs or beams without requiring full UE-specific signaling for all cases

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a multi-level signaling structure where higher-level (cell/beam) K_offset values serve as common references that can be applied universally to multiple UEs, while UE-specific K_offset provides individualized adjustments only when necessary. This multi-functionality reduces overall signaling overhead by avoiding redundant UE-specific signaling for UEs that don't require fine-tuned timing adjustments

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP4128918B1Uplink transmission scheduling in a non-terrestrial network

Publication Date: 2025.09.10 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD

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Figure 3A~3E

AI summary

A method for performing an uplink transmission by a user equipment in a non-terrestrial network. The method comprises : receiving, (210, 211) from a base station (110), a first information for indicating uplink transmission resources, and a second information, wherein the second information comprises a first parameter for indicating the uplink transmission resources; performing, based on the first information and the second information, (213) an uplink transmission on the uplink transmission resources.