UE Timing Advance Reporting for NTN Collision Avoidance

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Solution Overview

Problem

In non-terrestrial network (NTN) communications, user equipment (UE) timing advance (TA) reporting is challenging due to large timing delays, leading to potential collisions between downlink and uplink transmissions, as the base station may not be aware of the TA used by the UE, especially in systems like satellite communications, where the differential roundtrip time cannot be utilized for scheduling.

Innovation Solution

The UE is capable of auto-compensating time delays and reporting its TA to the network node through various methods, including medium access control (MAC) control elements, physical uplink control channel transmissions, or higher-layer signaling, allowing the network node to configure offset values for scheduling and preventing collisions by extending the value ranges of K1 and K2 offsets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the base station schedules downlink and uplink transmissions without knowing the UE's timing advance, then scheduling flexibility is improved, but transmission collisions occur between downlink and uplink

Engineering Contradiction:

Improvescheduling flexibilityVSAvoidtransmission collision avoidance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The UE reports its timing advance value to the base station through feedback mechanisms (MAC CE, PUCCH, or RRC signaling). This feedback enables the base station to know the actual TA used by the UE, allowing collision-free scheduling while maintaining scheduling flexibility.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The base station configures offset values (K1, K2) in advance based on the reported TA value. These pre-configured offsets ensure that future downlink and uplink transmissions will not collide, preventing collisions before they occur.

Inventive Principle:

Principle #10Preliminary action

2Loss of energy

If the UE auto-compensates time delays without reporting TA, then signaling overhead is reduced, but the base station cannot schedule transmissions without collisions

Engineering Contradiction:

Improvesignaling overheadVSAvoidscheduling capability

Core Design Contradiction:

Loss of energyVSEase of operation

Solution Approach 1:

Instead of full TA reporting in all scenarios, the system uses partial reporting only when needed (e.g., when TA changes significantly or based on configured thresholds). This reduces signaling overhead while maintaining sufficient scheduling capability.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The TA reporting mechanism serves multiple functions: it enables collision-free scheduling, provides timing synchronization information, and supports various duplexing modes (FDD, TDD). This multi-functionality justifies the signaling overhead by providing comprehensive scheduling capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If the differential roundtrip time window is reserved for downlink scheduling, then downlink scheduling capacity is improved, but the window cannot be used when TA is unknown

Engineering Contradiction:

Improvedownlink scheduling capacityVSAvoidscheduling safety

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The UE's TA report provides the base station with the necessary information to safely utilize the differential RTT window for downlink scheduling. With this feedback, the base station can calculate appropriate offset values and schedule downlink transmissions in previously unavailable time windows, increasing scheduling capacity without compromising safety.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11528676B2User equipment timing advance reporting in non-terrestrial network communications

Publication Date: 2022.12.13 MEDIATEK SINGAPORE PTE LTD

AI summary

Various solutions for timing advance (TA) reporting by a user equipment (UE) in non-terrestrial network (NTN) communications are described. An apparatus (e.g., a UE), capable of auto-compensation of time delays in signaling, establishes a wireless connection with a network node of a wireless network. The apparatus then transmits a TA report to the network node. Based on the TA, the network can configure a UE-specific offset for UL scheduling.