Directional LBT COT Start Mechanism

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently starting a channel occupancy time (COT) after a directional listen-before-talk (LBT), particularly in the 60 GHz band where arbitrary pauses in transmission are allowed, leading to undefined effects on the start of COT and maximum channel occupancy time.

Innovation Solution

A transmitting node performs a directional LBT using a sensing beam and starts a COT based on either a COT claiming signal or a time stamp, allowing for transmissions during the COT using transmit beams included in the sensing beam, thereby addressing the challenge of undefined pauses in the 60 GHz band.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If arbitrary pauses are allowed in transmission in the 60 GHz band, then transmission flexibility is improved, but the definition of COT start time becomes undefined

Engineering Contradiction:

Improvetransmission flexibilityVSAvoidCOT start time definition

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent applies preliminary action by establishing clear COT start time determination rules before arbitrary pauses occur. The transmitting node determines the COT start time based on either the LBT completion time or the paused transmission time point in advance, ensuring that even when pauses are inserted during transmission, the COT start time remains well-defined and unambiguous.

Inventive Principle:

Principle #10Preliminary action

2Duration of action of stationary object

If COT is started after arbitrary pauses, then transmission continuity is improved, but timing precision deteriorates

Engineering Contradiction:

Improvetransmission continuityVSAvoidCOT start time precision

Core Design Contradiction:

Duration of action of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by providing multiple COT start time determination methods depending on the transmission scenario. When arbitrary pauses are present, the system switches to using the paused transmission time point as the COT start time reference, rather than the LBT completion time. This parameter change maintains timing precision while allowing transmission continuity through pauses.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If directional LBT is performed with sensing beams, then spatial reuse is improved, but system complexity increases

Engineering Contradiction:

Improvespatial reuseVSAvoidbeam management complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies merging by combining the COT start time determination with the directional LBT procedure. The COT start time is determined based on the LBT completion time or the paused transmission time point, integrating the timing mechanism into the existing beam-based LBT framework. This merging approach enables spatial reuse through directional sensing while avoiding separate complex timing management systems.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12250721B2Starting a channel occupancy time after a directional listen-before-talk

Publication Date: 2025.03.11 QUALCOMM INC

AI summary

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a transmitting node may perform a directional listen-before-talk (LBT) using a sensing beam. The transmitting node may start a channel occupancy time (COT) after the directional LBT based at least in part on one of a COT claiming signal or a time stamp. The transmitting node may perform, to a receiving node, one or more transmissions during the COT using one or more transmit beams that are included in the sensing beam. Numerous other aspects are described.