NR-U Slot Format Indicator Segmentation for Lower Access Latency

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Solution Overview

Problem

Existing wireless communication systems face inefficiencies and increased latency due to the need for medium-sensing procedures when multiple network operating entities contend for access to shared unlicensed spectrum, leading to potential interference and communication bottlenecks.

Innovation Solution

Implement a method for coordinated resource partitioning using a slot format indicator (SFI) that separates channel occupancy time (COT) range indication from SFI, employing a three-segment structure to enhance communication efficiency and reduce interference by prioritizing network operators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If medium-sensing procedures are implemented when multiple network operating entities contend for access to shared unlicensed spectrum, then interference between entities is reduced, but communication latency increases and system efficiency decreases

Engineering Contradiction:
Improveinterference reductionVSAvoidcommunication latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The COT is divided into multiple segments with different priority levels (first priority, second priority, third priority segments). This segmentation allows different network operating entities to access resources in an organized manner, reducing contention and medium-sensing procedures while maintaining interference control through structured priority-based access.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent establishes COT structure and priority allocations in advance through signaling between network operating entities. By pre-defining which entities have access to which priority segments during which time periods, the system eliminates the need for real-time medium-sensing procedures, thereby reducing latency while maintaining interference control.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If coordinated resource partitioning with priority segments is implemented, then system efficiency and resource utilization improve, but signaling overhead increases

Engineering Contradiction:
Improvesystem efficiencyVSAvoidsignaling overhead
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The COT structure and priority allocation framework serves multiple functions simultaneously: it defines resource partitioning, establishes access priorities, coordinates between different network operating entities, and enables efficient spectrum utilization. This multi-functionality reduces the need for separate signaling mechanisms, thereby improving system efficiency while limiting the increase in signaling overhead.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If COT structure is established in advance through signaling, then medium access coordination improves and interference is reduced, but flexibility in dynamic spectrum conditions decreases

Engineering Contradiction:
Improveaccess coordinationVSAvoiddynamic spectrum adaptation
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic COT structure where the network operating entity with the lowest priority can request extensions to its COT when spectrum conditions permit. This dynamic adjustment mechanism allows the system to maintain pre-established coordination for reliability while adapting to changing spectrum conditions, thereby balancing both requirements.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3881587B1Slot format indicator enhancements for new radio-unlicensed
Publication Date: 2026.02.18 QUALCOMM INC
  • EP3881587B1 patent drawingFigure 1
  • EP3881587B1 patent drawingFigure 2
  • EP3881587B1 patent drawingFigure 3

AI summary

Enhancements to slot format indicator (SFI) for new radio (NR) unlicensed (NR-U) operations is disclosed. The SFI may be transmitted separately from a channel occupancy time (COT) range indication. The COT range indication identifies parameters of a three-segment structure of a current COT within the current TxOP. Upon receiving the SFI and COT range indication, a UE may engage in communications with the serving UE in accordance with the COT range indication and the SFI.