SL-U MAC PDU Regeneration for CAPC-Aware V2X Transmission

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Solution Overview

Problem

The increasing demand for enhanced mobile broadband communication and the need for reliable and low-latency wireless communication in vehicle-to-everything (V2X) scenarios necessitates improved methods for managing channel access and data transmission in sidelink (SL) communication.

Innovation Solution

A method and apparatus for generating and regenerating medium access control (MAC) protocol data units (PDUs) based on channel access priority class (CAPC) values and channel occupancy time (COT) information, allowing for efficient wireless communication by prioritizing data transmission in sidelink environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If MAC PDU is generated based on all available data without regeneration, then data transmission volume is maximized, but transmission reliability decreases when channel conditions change

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidMAC PDU management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The MAC PDU structure is made dynamic through regeneration based on current channel conditions. The transmitting device receives updated CAPC values and COT information, then regenerates the MAC PDU to reflect current transmission priorities and channel occupancy constraints, transforming a static data structure into an adaptive one that responds to real-time channel variations

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The receiving device provides feedback by transmitting updated CAPC values and COT information to the transmitting device. This feedback loop enables the transmitting device to regenerate the MAC PDU with current channel access priorities and occupancy time constraints, ensuring transmission reliability aligns with actual channel conditions

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If MAC PDU regeneration is performed frequently based on CAPC updates, then transmission adaptability improves, but processing time and latency increase

Engineering Contradiction:
Improvetransmission adaptabilityVSAvoidMAC PDU processing time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The MAC PDU is initially generated with placeholder or default data structures that can be quickly updated during regeneration. This preliminary structuring allows subsequent regeneration operations to focus only on modifying specific fields (such as priority indicators and occupancy time parameters) rather than reconstructing the entire PDU, thereby reducing processing time while maintaining adaptability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The MAC PDU regeneration process updates only the specific portions of the data structure that are affected by changing channel conditions, such as priority indicators and occupancy time parameters, while preserving other unchanged portions. This localized update approach minimizes processing time while maintaining transmission adaptability

Inventive Principle:
Principle #3Local quality

3Measurement precision

If channel access priority class information is exchanged between devices, then transmission prioritization accuracy improves, but communication overhead increases

Engineering Contradiction:
Improvepriority classification accuracyVSAvoidcommunication overhead
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The CAPC value and COT information serve multiple functions: they guide MAC PDU regeneration, determine transmission timing, prioritize data segments, and coordinate channel access between devices. By making this information multi-functional, the patent reduces the need for separate signaling messages for each function, thereby improving priority classification accuracy while minimizing communication overhead

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

Data Source

PatentEP4611468A1Separation operation method and apparatus of mac PDU generated from SL-u
Publication Date: 2025.09.03 LG ELECTRONICS INC
  • EP4611468A1 patent drawingFigure 1
  • EP4611468A1 patent drawingFigure 2
  • EP4611468A1 patent drawingFigure 3

AI summary

Provided are a method by which a first device performs wireless communication and an apparatus supporting same. The method may comprise the steps of: generating a medium access control (MAC) protocol data unit (PDU) on the basis of available data; receiving, from a second device, information associated with a channel occupancy time (COT) and a channel access priority class (CAPC) value; and regenerating the MAC PDU on the basis of available data associated with a CAPC value that is less than or equal to the CAPC value from among the available data included in the MAC PDU.