Slot Format Index Preemption for Cross-Link Interference

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Solution Overview

Problem

Existing wireless communication systems face challenges with cross-link interference due to uplink-downlink symbol mismatches in slot format indices (SFIs), particularly in scenarios involving carrier aggregation and co-located base stations, leading to increased self-interference and failed downlink transmissions.

Innovation Solution

User Equipment (UE) determines and requests to avoid specific SFIs that are likely to cause cross-link interference by measuring and reporting beam-specific interference, allowing base stations to adjust their configurations to minimize uplink-downlink mismatches and reduce interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If slot format indices are used for carrier aggregation in co-located base stations, then communication flexibility and resource utilization are improved, but cross-link interference increases due to uplink-downlink symbol mismatches

Engineering Contradiction:
Improvecommunication flexibilityVSAvoidcross-link interference
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system proactively identifies and reports SFIs that are likely to cause cross-link interference before actual transmissions occur. The UE measures beam-specific interference characteristics and reports them to the network, enabling preemptive configuration adjustments to avoid harmful uplink-downlink symbol mismatches.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the UE measures and reports beam-specific interference information related to different SFIs. This feedback loop allows the network to adjust slot format configurations based on actual interference conditions, resolving the contradiction between communication flexibility and interference avoidance.

Inventive Principle:
Principle #23Feedback

2Device complexity

If base stations use fixed slot format configurations, then interference management is simplified, but communication reliability decreases due to inability to adapt to dynamic interference conditions

Engineering Contradiction:
Improveconfiguration management complexityVSAvoiddownlink transmission reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The UE autonomously performs measurements of beam-specific interference characteristics and independently determines which SFIs are likely to cause cross-link interference. This self-service approach reduces the signaling overhead and complexity for the network while improving reliability through UE-specific interference adaptation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system dynamically changes SFI configurations based on measured interference parameters. The UE reports beam-specific interference measurements that characterize different SFI conditions, enabling the network to select optimal configurations that adapt to changing interference environments while maintaining manageable complexity.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If UE reports detailed beam-specific interference measurements, then interference avoidance accuracy is improved, but signaling overhead and processing requirements increase

Engineering Contradiction:
Improveinterference measurement accuracyVSAvoidsignaling overhead
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent extracts only the essential interference information needed for SFI selection from comprehensive beam measurements. The UE identifies and reports specific SFIs that are likely to cause cross-link interference based on beam-specific measurements, rather than reporting all possible measurement data, thus reducing signaling overhead while maintaining avoidance accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4128625B1Preemption of symbols in a slot format index
Publication Date: 2025.06.25 QUALCOMM INC
  • EP4128625B1 patent drawingFigure 1
  • EP4128625B1 patent drawingFigure 2
  • EP4128625B1 patent drawingFigure 3

AI summary

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may determine, for communications via a component carrier, to avoid one or more slot format indices (SFIs) associated with a set of configurations for a set of symbols; and transmit a request to avoid the one or more SFIs. Numerous other aspects are provided.