Sidelink Feedback Control for LTE and NR V2X Coexistence

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Solution Overview

Problem

In wireless communications systems, UEs operating on different radio access technologies (RATs like LTE V2X and NR V2X) face resource collisions due to overlapping frequency resources, leading to limited choices for NR V2X transmissions and inefficient use of resources when there is no coordination for resource selection.

Innovation Solution

Implement techniques to disable sidelink feedback-based transmissions for NR V2X UEs under specific conditions, such as detecting a certain number of LTE V2X resource reservations, to prevent resource exclusion and enhance coexistence with LTE V2X transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If NR V2X transmissions use feedback-based retransmissions on overlapping frequency resources with LTE V2X, then communication reliability is improved through HARQ feedback, but resource collisions increase and available resources for NR V2X are limited

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidavailable resources for NR V2X

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the feedback request parameter dynamically based on detected LTE V2X reservation conditions. When LTE V2X reservations are detected in the same channel, the NR V2X transmission selectively disables feedback requests, adjusting the communication protocol parameter to avoid resource collisions while maintaining reliability when resources are available

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamic adaptation of feedback-based retransmission behavior. The NR V2X transmission dynamically switches between enabling and disabling feedback requests based on real-time detection of LTE V2X resource reservations, making the system flexible and adaptive to changing channel conditions

Inventive Principle:

Principle #15Dynamics

2Reliability

If NR V2X transmissions request feedback for retransmissions, then transmission reliability is improved, but resource collisions with LTE V2X increase

Engineering Contradiction:

Improvetransmission reliabilityVSAvoidresource collisions

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by detecting LTE V2X resource reservations before NR V2X transmissions occur. This advance detection allows the system to preemptively disable feedback requests that would cause resource collisions, preventing the harmful effect before it occurs

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent introduces an intermediary detection mechanism that monitors LTE V2X resource reservations. This intermediary function acts as a mediator between NR V2X transmission requirements and LTE V2X resource usage, enabling the system to adjust feedback requests based on detected collision conditions

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12621721B2Sidelink feedback management during a same channel co-existence

Publication Date: 2026.05.05 QUALCOMM INC

AI summary

Certain aspects of the present disclosure provide a method for wireless communications at a first user equipment (UE). The first UE may detect at least one condition related to first resources reserved for sidelink transmissions in a first radio access technology (RAT). The first UE may perform one or more actions, based on the detection, to limit feedback request for sidelink transmissions in a second RAT.