Parallel LBT Indication Across Frequency Resources for RACH Access

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Solution Overview

Problem

Devices accessing the unlicensed band face challenges in transmitting within available time windows due to factors hindering channel access, leading to delayed or missed transmissions that negatively affect upper layer processing.

Innovation Solution

Configuring multiple sub-band RACH resources and implementing a mechanism to terminate pending LBT attempts upon successful LBT procedures, enhancing processing performance by managing LBT outcomes across different layers of the OSI model.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple frequency resources are configured for random access, then the probability of channel access improves, but the complexity of managing LBT procedures and indications increases

Engineering Contradiction:
Improvechannel access probabilityVSAvoidLBT procedure management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the LBT procedure management by separating concerns between layers: the first layer executes LBT procedures for multiple frequency resources and generates outcome indications, while the second layer receives these indications and makes transmission decisions. This segmentation reduces the complexity burden on any single layer while maintaining high channel access probability through parallel LBT attempts across multiple frequency resources.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If LBT procedures are performed for each frequency resource, then channel access opportunities increase, but the processing time and delay for upper layers increase

Engineering Contradiction:
Improvechannel access opportunitiesVSAvoidprocessing delay
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent implements preliminary action by having the first layer perform LBT procedures for multiple frequency resources in advance and prepare outcome indications before upper layers need to make transmission decisions. The first layer proactively identifies successful frequency resources and communicates this information to the second layer, reducing the time upper layers would otherwise spend on channel access decisions and minimizing processing delays.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If parallel LBT procedures are executed across multiple frequency resources, then transmission success rate improves, but the resource coordination and indication management becomes more complex

Engineering Contradiction:
Improvetransmission success rateVSAvoidresource coordination complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary mechanism where the first layer acts as a mediator between the physical radio resources and the second layer's transmission decisions. The first layer receives multiple frequency resources, executes parallel LBT procedures, consolidates the outcomes into standardized indications, and presents this processed information to the second layer. This intermediary role simplifies resource coordination complexity by centralizing the management of parallel LBT procedures in the first layer while providing a clean interface to the second layer.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3964008B1Methods for multiple parallel messaging indication
Publication Date: 2025.12.10 ZTE CORP
  • EP3964008B1 patent drawingFigure 1
  • EP3964008B1 patent drawingFigure 2
  • EP3964008B1 patent drawingFigure 3

AI summary

A system and method of terminating any pending listen-before-talk (LBT) attempts after they have been submitted to the physical layer of a system interconnection model if one or more of the LBT attempts succeed. The system and method include receiving a plurality of frequency resources, each of the plurality of frequency resources corresponding to a respective resource occasion. The system and method include performing, for each of the frequency resources, a listen-before-talk procedure in a first layer of an open system interconnection model. The system and method include indicating, to a second layer of the open system interconnection model, a first one of the plurality of frequency resources that succeeded in the respective listen-before-talk procedure.