UE-to-UE Channel Occupancy Time Sharing in Shared Spectrum

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Solution Overview

Problem

Current wireless communication systems face inefficiencies in channel occupancy time (COT) sharing among user equipment (UEs) in shared radio frequency spectrum, particularly when implementing category 4 (CAT4) listen-before-talk (LBT) procedures, which are complex and wasteful for small payload transmissions.

Innovation Solution

The proposed techniques enable UE-to-UE sharing of channel occupancy time (COT) in shared spectrum by allowing UEs to acquire and share COT using a shortened LBT procedure, reducing the need for extended LBT processes and improving resource utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If CAT4 LBT procedure is used for channel access in shared spectrum, then channel access fairness is improved, but implementation complexity increases and resource utilization efficiency deteriorates for small payload transmissions

Engineering Contradiction:

Improvechannel access fairnessVSAvoidimplementation complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the channel access process by introducing COT sharing, where one UE acquires the channel using CAT4 LBT and shares it with other UEs. This divides the complex CAT4 LBT requirement into two parts: one UE performs full CAT4 LBT, while other UEs use simplified access methods within the shared COT, reducing overall system complexity while maintaining fairness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by having one UE acquire the COT in advance using CAT4 LBT before other UEs transmit. This pre-acquisition creates a shared channel occupancy time that other UEs can utilize with simplified procedures, eliminating the need for each UE to independently perform complex CAT4 LBT while preserving fair channel access.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If CAT4 LBT procedure is used for channel access in shared spectrum, then channel access fairness is improved, but resource utilization efficiency deteriorates for small payload transmissions

Engineering Contradiction:

Improvechannel access fairnessVSAvoidresource utilization efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges multiple UEs' channel access needs into a single COT acquisition event. Instead of each UE performing independent CAT4 LBT, one UE acquires the channel and shares it with multiple other UEs, combining their access rights into a unified time resource that improves overall resource utilization efficiency while maintaining fair access through the original CAT4 LBT performance.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

By having one UE perform CAT4 LBT in advance to acquire COT, the patent enables subsequent UEs to transmit without repeating the complex procedure. This preliminary action creates a shared resource that multiple UEs can efficiently utilize, particularly benefiting small payload transmissions where repeated CAT4 LBT would be wasteful.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If each UE performs independent CAT4 LBT for channel access, then channel access fairness is maintained, but implementation complexity and transmission overhead increase

Engineering Contradiction:

Improvechannel access fairnessVSAvoidease of channel access

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent segments the channel access burden by designating one UE to perform CAT4 LBT and share the acquired COT with other UEs. This segmentation reduces the operational complexity for individual UEs, as they no longer need to independently execute the complex CAT4 LBT procedure, while the system as a whole maintains fair access through the initial acquisition.

Inventive Principle:

Principle #1Segmentation

4Device complexity

If UEs use shortened LBT procedure within shared COT, then implementation complexity is reduced and resource utilization is improved, but channel access fairness may deteriorate

Engineering Contradiction:

Improveimplementation complexityVSAvoidchannel access fairness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent uses preliminary action to resolve this contradiction: one UE performs the full CAT4 LBT procedure in advance to acquire the COT, establishing fair channel access. Subsequent UEs then use shortened LBT within this pre-acquired COT, reducing their complexity burden while the initial fair access is preserved through the preliminary CAT4 LBT performance by the first UE.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11432325B2Methods, apparatuses and systems for user equipment (UE)-to-UE sharing of channel occupancy time

Publication Date: 2022.08.30 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communication are described. A base station may determine a configuration for UE-to-UE sharing of a channel occupancy time (COT) and may transmit the configuration to a UE to indicate that it can share a UE-acquired COT with at least another UE. A UE may acquire a COT using a listen-before-talk (LBT) procedure, and if successful, may transmit a signal indicating that the COT is being shared with at least another UE. Additionally, a UE may receive a signal from another UE indicating that it has acquired a COT in a shared spectrum and that the COT is being shared with other UEs. The UE may perform a shortened LBT procedure within the COT, and if successful, may transmit an uplink transmission in the shared spectrum.