User Equipment LBT Type Determination for 5G Unlicensed Spectrum

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Solution Overview

Problem

In 5G networks using unlicensed spectrum, communication devices face challenges in efficiently determining the appropriate Listen-Before-Talk (LBT) type for channel access, which affects the fairness and probability of obtaining channels.

Innovation Solution

A method for user equipment (UE) to determine the LBT type for Physical Uplink Shared CHannel (PUSCH) transmission based on indications from Downlink Control Information (DCI), where the UE can switch between indicated and default LBT types depending on the alignment of PUSCH resources with Base Station Channel Occupancy Time (BS COT).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If UE performs standard LBT procedure to obtain channel access, then channel access fairness is maintained, but channel acquisition probability decreases and transmission delay increases

Engineering Contradiction:

Improvechannel access fairnessVSAvoidchannel acquisition probability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic LBT type selection where the UE adapts its channel access strategy based on real-time conditions. The network can indicate different LBT types (Type 1 with full LBT procedure, Type 2 with simplified LBT) through DCI signaling, allowing the system to switch between conservative and aggressive channel access modes depending on channel occupancy time alignment and scheduling requirements, thereby resolving the contradiction between fairness and acquisition probability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the LBT procedure parameters dynamically by introducing multiple LBT types with different contention window sizes, sensing durations, and priority levels. The network configures these parameters through RRC signaling and activates specific configurations via DCI, enabling the UE to adjust its channel access behavior to achieve both fairness and high acquisition probability under different network conditions

Inventive Principle:

Principle #35Parameter changes

2Productivity

If UE uses quick LBT type when BS COT is shared, then channel acquisition probability increases, but device complexity and signaling overhead increase

Engineering Contradiction:

Improvechannel acquisition probabilityVSAvoidLBT type determination complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by having the network pre-configure multiple LBT type configurations and associated parameters through RRC signaling before actual channel access is needed. The UE stores these pre-configured options and simply selects from them based on network indication, avoiding complex real-time calculations and reducing both device complexity and signaling overhead during actual transmission

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces the network's DCI signaling as an intermediary that mediates between the complex LBT type determination logic and the UE implementation. Instead of requiring the UE to independently determine the appropriate LBT type based on complex channel state analysis, the network acts as an intermediary that provides the optimal LBT type indication, simplifying the UE's decision-making process while maintaining high channel acquisition probability

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12284672B2Method of LBT type determination and user equipment

Publication Date: 2025.04.22 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD

AI summary

A method, a User Equipment, a computer program and a computer readable medium for LBT determination are provided.