Shared-Spectrum Uplink Timing with LBT-LBE Synchronization

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Solution Overview

Problem

In wireless communication systems, there is uncertainty regarding when and if a user equipment (UE) will successfully contend for access to a shared radio frequency spectrum band, such as an unlicensed band, using an LBT-LBE protocol, which affects the reliability of uplink transmissions.

Innovation Solution

The proposed solution involves managing uplink resources by synchronizing the gating intervals of the LBT-LBE protocol with periodic intervals of cellular communication systems, such as LTE/LTE-A, to determine optimal transmission times and ensure efficient access to the shared spectrum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LBT-LBE protocol is used to contend for access to unlicensed spectrum, then channel access reliability is improved, but transmission timing uncertainty increases

Engineering Contradiction:

Improvechannel access reliabilityVSAvoidtransmission timing uncertainty

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The base station performs preliminary actions by determining a set of candidate uplink resources in advance, before the actual uplink transmission occurs. These candidate resources are prepared based on expected timing scenarios, allowing the UE to quickly select appropriate resources without waiting for timing clarification, thus reducing the impact of timing uncertainty while maintaining reliable channel access through LBT-LBE

Inventive Principle:

Principle #10Preliminary action

2Reliability

If multiple candidate uplink resources are provided to UE, then transmission reliability is improved, but resource management complexity increases

Engineering Contradiction:

Improvetransmission reliabilityVSAvoidresource management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The set of candidate uplink resources is segmented based on different timing scenarios (e.g., different possible transmission timings). Each segment corresponds to a specific timing condition, making it easier for the UE to select the appropriate segment without having to manage all resources uniformly. This segmentation reduces the cognitive complexity at the UE while maintaining multiple resource options for reliability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The base station changes the parameter of resource allocation by providing multiple candidate resources with different timing characteristics rather than a single fixed resource. This parameter diversification allows the system to adapt to timing uncertainties without requiring complex management mechanisms, as the resources are differentiated by clear timing parameters

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3823399B1Techniques for managing resources for uplink transmissions in a shared radio frequency spectrum band

Publication Date: 2025.09.24 QUALCOMM INC

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AI summary

Techniques are described for wireless communication. A first method includes identifying a first interval for an uplink transmission in a shared radio frequency spectrum band; determining a portion of the first interval is unavailable for the uplink transmission in the shared radio frequency band; identifying a second interval for the uplink transmission based at least in part on the determination that a portion of the first interval is unavailable; and transmitting the uplink transmission during the second interval.