Dynamic Energy Thresholds for Unlicensed-Band Sidelink Access

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Solution Overview

Problem

The increasing demand for mobile broadband communication and V2X services in wireless communication systems necessitates efficient channel access mechanisms, particularly in unlicensed bands, to manage channel occupancy times and energy detection thresholds for reliable and low-latency sidelink transmissions.

Innovation Solution

A method and device for performing wireless communication that involves obtaining a channel occupancy time (COT), configuring an energy detection threshold based on T_A, and performing a channel access procedure to determine idle sensing slots for sidelink (SL) transmission, ensuring SL transmission occurs outside the COT.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed energy detection threshold is used for channel sensing, then the channel access procedure is simple, but the reliability of SL transmission is degraded due to interference from other RATs

Engineering Contradiction:
Improvereliability of SL transmissionVSAvoidcomplexity of channel access procedure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The energy detection threshold is made dynamic by adjusting it based on the COT duration obtained from other RAT systems. The threshold is set to a first value when SL transmission occurs within the COT and to a second value when it occurs outside the COT, allowing the system to adapt to changing channel conditions and interference levels.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The energy detection threshold parameter is changed based on the transmission timing relative to the COT. By switching between different threshold values depending on whether the transmission occurs inside or outside the COT duration, the system optimizes detection accuracy while maintaining procedural simplicity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If channel sensing is performed continuously, then the channel access reliability is improved, but the latency for SL transmission increases

Engineering Contradiction:
Improvechannel access reliabilityVSAvoidlatency for SL transmission
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary channel sensing only when necessary (outside the COT duration) rather than continuously. By determining in advance whether the channel is idle before the COT expires and preparing transmission resources accordingly, the system reduces unnecessary sensing operations and associated latency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The channel access procedure skips the energy detection step entirely when SL transmission occurs within the COT duration, as the channel is already known to be occupied by the other RAT system. This allows the system to rush through the transmission without additional sensing delays.

Inventive Principle:
Principle #21Skipping (Rushing through)

3Measurement precision

If the energy detection threshold is set low to detect idle channels accurately, then the channel sensing precision is improved, but false detection of busy channels increases due to interference

Engineering Contradiction:
Improveprecision of channel sensingVSAvoidfalse detection due to interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

Different energy detection threshold values are applied locally based on the transmission timing context. A first threshold value is used when transmission occurs within the COT (where interference from the other RAT is expected), and a second threshold value is used when transmission occurs outside the COT (where the channel should be clearer). This localized adaptation of threshold quality optimizes detection accuracy for each scenario.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4642139A1Method and device for performing channel access on basis of energy detection threshold in unlicensed band
Publication Date: 2025.10.29 LG ELECTRONICS INC
  • EP4642139A1 patent drawingFigure 1
  • EP4642139A1 patent drawingFigure 2
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AI summary

A method for performing wireless communication by a first device and a device for supporting same are provided. The method may comprise the steps of: obtaining a channel occupancy time (COT); configuring an energy detection threshold for determining whether a sensing slot duration is idle; performing a channel access procedure on the basis of the energy detection threshold; and performing sidelink (SL) transmission.