Uplink Channel Access in Unlicensed Bands via Dynamic Type Selection

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Solution Overview

Problem

The use of unlicensed frequency bands in cellular communication systems faces challenges in maintaining communication quality due to interference with conventional wireless devices, such as Wi-Fi, and inefficient radio channel sharing, necessitating a robust coexistence mechanism to prevent disruption of conventional unlicensed band devices.

Innovation Solution

A method for performing uplink transmission in a wireless communication system using an unlicensed cell, where the user equipment receives an uplink grant from the base station and performs channel access using either a first type or second type channel access, with the second type access employed when all subframes are within a predetermined interval based on downlink transmission, to manage channel access and minimize interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If unlicensed band is used for cellular communication service, then spectrum availability is improved, but communication quality guarantee deteriorates

Engineering Contradiction:

Improvespectrum availabilityVSAvoidcommunication quality guarantee

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements dynamic channel access type selection based on timing relationships. The UE determines whether to use first type or second type channel access dynamically based on whether the uplink subframe falls within the predetermined interval after downlink transmission, allowing the system to adapt to varying channel conditions and interference scenarios in unlicensed bands

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the channel access parameter (access type) based on the timing relationship between downlink and uplink transmissions. By switching between different channel access types (first type with full LBT procedure vs. second type with simplified access), the system optimizes both spectrum utilization and communication reliability under different conditions

Inventive Principle:

Principle #35Parameter changes

2Productivity

If multiple communication facilities use unlicensed band simultaneously, then spectrum utilization is improved, but interference with conventional devices increases

Engineering Contradiction:

Improvespectrum utilizationVSAvoidinterference with conventional devices

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by implementing Listen-Before-Talk (LBT) channel access procedures before uplink transmissions. The UE performs channel sensing and selects appropriate access types to avoid collisions with conventional unlicensed band devices like Wi-Fi, thereby reducing interference while maintaining spectrum utilization

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent implements periodic channel access procedures with different types based on timing. The first type channel access is used periodically for independent uplink transmissions, while the second type is used within predetermined intervals after downlink transmissions, creating a structured periodic access pattern that coexists with other unlicensed band users

Inventive Principle:

Principle #19Periodic action

3Object-affected harmful factors

If first type channel access is used for all uplink transmissions, then interference avoidance is improved, but channel access efficiency deteriorates

Engineering Contradiction:

Improveinterference avoidanceVSAvoidchannel access efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies local quality by using different channel access types in different time situations. Instead of uniformly applying the conservative first type channel access everywhere, the system uses the more efficient second type channel access in local time windows (within predetermined intervals after downlink transmission) where interference risk is lower, thereby optimizing overall channel access efficiency while maintaining adequate interference avoidance

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250105953A1Method for uplink channel access to unlicensed band in wireless communication system, and device therefor

Publication Date: 2025.03.27 WILUS INSTITUTE OF STANDARDS & TECHNOLOGY INC

AI summary

A method for performing an uplink transmission to a base station by a user equipment through an unlicensed cell in a wireless communication system is provided. The method includes: receiving an uplink grant that schedules the uplink transmission in at least one subframe from the base station; and performing the uplink transmission in the at least one subframe using at least one of a first type channel access or a second type channel access. The uplink transmission is performed using the second type channel access when all of the at least one subframe is included in a predetermined interval determined based on a downlink transmission through the unlicensed cell from the base station.