Conditional MAC Counter Increment for LBT Failure Recovery

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Solution Overview

Problem

In mobile communications, the Listen-Before-Talk (LBT) failure detection and recovery procedure (LFDRP) may not function properly when not configured, leading to stuck procedures during random access (RA) or scheduling request (SR) transmissions due to unincremented counters, preventing recovery actions in 5G NR-based access to unlicensed spectrum.

Innovation Solution

A processor in a user equipment (UE) determines the status of the LBT failure detection and recovery feature, conditionally incrementing counters for RA and SR procedures based on whether the LFDRP is configured, ensuring that recovery actions can be taken when necessary by considering LBT failure indications from lower layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the MAC layer does not increment counters when LBT failure indication is received, then LBT failure detection is improved, but the procedure gets stuck without recovery actions

Engineering Contradiction:

ImproveLBT failure detection accuracyVSAvoidProcedure recovery capability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent applies dynamics by making the counter increment behavior conditional rather than static. The MAC layer dynamically adjusts whether to increment counters based on the configuration status of LFDRP, allowing the system to adapt its behavior to different operational contexts (configured vs. not configured) to resolve the contradiction between detection accuracy and recovery capability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of counter incrementing behavior based on the LFDRP configuration status. When LFDRP is not configured, the MAC layer changes its parameter to increment counters even upon LBT failure, enabling recovery actions while maintaining detection functionality

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If the LFDRP configuration is not present, then initial access is simplified, but the MAC layer cannot execute recovery actions

Engineering Contradiction:

ImproveInitial access configurationVSAvoidRecovery action execution

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by preparing alternative counter incrementing logic in advance for scenarios where LFDRP is not configured. The MAC layer is pre-configured with conditional behavior that activates when LFDRP configuration is absent, ensuring recovery capability is ready before the problem occurs

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary conditional check regarding LFDRP configuration status that mediates between the simplified initial access (no LFDRP config) and the need for recovery actions. This intermediary mechanism determines the appropriate counter incrementing behavior based on configuration presence

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11570812B2Conditions on listen-before-talk impact on mac counters in mobile communications

Publication Date: 2023.01.31 HFI INNOVATION INC

AI summary

Various schemes pertaining to conditions on LBT impact on MAC counters in mobile communications involve a user equipment (UE) determining a status of a listen-before-talk (LBT) failure detection and recovery feature. Based on the status of the LBT failure detection and recovery feature (e.g., whether the LBT failure detection and recovery feature is configured or not configured), a preamble transmission counter in a random access (RA) procedure or a scheduling request (SR) counter in a SR procedure is conditionally incremented in the event of an LBT failure.