NR V2X MAC Reset Handling for Sidelink DRX Command Cancellation

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Solution Overview

Problem

Existing wireless communication technologies face inefficiencies in managing MAC resets for sidelink communication, leading to unnecessary generation and signaling of DRX command MAC CEs and disruption of DRX timers, which affect the monitoring of PSCCH/PSSCH channels.

Innovation Solution

The proposed solution involves a method and apparatus for managing MAC resets by canceling triggered SL DRX command MAC CE reporting and stopping SL DRX timers based on requested MAC resets for PC5-RRC connections, ensuring efficient sidelink communication by maintaining appropriate monitoring times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a UE receives a request for sidelink interface MAC reset, then the MAC parameters related to SL communication are reset and SL communication operations are stopped, but a DRX command MAC CE may be unnecessarily generated and signaled, causing unnecessary DRX timer stops

Engineering Contradiction:

ImproveMAC reset operation reliabilityVSAvoidunnecessary DRX timer stops

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies preliminary anti-action by checking whether a DRX command MAC CE should be generated before actually generating it. When a MAC reset request is received for the sidelink interface, the method proactively determines that generating a DRX command MAC CE would be unnecessary and prevents its generation, thereby avoiding the harmful effect of unnecessary DRX timer stops.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent converts the potentially harmful effect of unnecessary DRX command MAC CE generation into a benefit by implementing a check mechanism. The harmful action (generating DRX command MAC CE) is identified and converted into a beneficial outcome (avoiding unnecessary timer stops) through the conditional check that determines whether the DRX command should be generated based on the current MAC reset state.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Use of energy by stationary object

If a DRX command MAC CE is generated upon MAC reset request, then the DRX timer is stopped to save energy, but PSCCH/PSSCH monitoring is unnecessarily disrupted

Engineering Contradiction:

ImproveDRX timer energy managementVSAvoidPSCCH/PSSCH monitoring reliability

Core Design Contradiction:

Use of energy by stationary objectVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by checking the necessity of generating a DRX command MAC CE before generation. When a MAC reset request is received, the method proactively determines that generating the DRX command would disrupt PSCCH/PSSCH monitoring unnecessarily, and prevents its generation, thereby maintaining monitoring reliability while still managing DRX timers appropriately.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent uses feedback by implementing a conditional check that monitors the MAC reset request state and determines whether generating a DRX command MAC CE would be appropriate. This feedback mechanism ensures that the system only generates the DRX command when actually necessary, preventing harmful disruptions to PSCCH/PSSCH monitoring while maintaining proper energy management.

Inventive Principle:

Principle #23Feedback

3Productivity

If MAC reset is performed for PC5-RRC connection, then SL communication is reset according to existing technology, but unnecessary DRX command signaling increases protocol overhead

Engineering Contradiction:

ImproveMAC reset processing efficiencyVSAvoidDRX command MAC CE signaling quantity

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent applies the taking out principle by extracting and removing the unnecessary DRX command MAC CE generation step from the MAC reset process. When a MAC reset request is received for the PC5-RRC connection, the method identifies and excludes the generation of DRX command MAC CE from the processing sequence, thereby reducing protocol overhead and signaling quantity while maintaining essential MAC reset functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies parameter changes by modifying the behavior of the DRX command MAC CE generation parameter. Instead of always generating the DRX command upon MAC reset, the system changes the generation parameter to be conditional, only generating the command when actually necessary. This reduces the quantity of DRX command signaling while maintaining appropriate DRX timer management.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP4271112B1Method and apparatus for performing radio communication related to mac reset in NR v2x

Publication Date: 2025.12.24 LG ELECTRONICS INC

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AI summary

A method for performing wireless communication by a first device and an apparatus supporting the same are proposed. For example, the first device may obtain an SL DRX configuration including information related to an SL DRX cycle and information related to a timer for active time. For example, the timer for active time may include at least one of an SL DRX on-duration timer or an SL DRX inactivity timer. For example, the first device may trigger SL DRX command MAC CE reporting related to the PC5-RRC connection. For example, the first device may cancel the triggered SL DRX command MAC CE reporting, based on an MAC reset for the PC5-RRC connection being requested.