V2X Resource Reservation Under High Channel Busy Ratio

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Solution Overview

Problem

In wireless communications systems, particularly under congested conditions, user equipment (UE) faces challenges in efficiently reserving resources for both initial and retransmission of messages due to limitations imposed by channel busy ratios, leading to reduced performance and increased packet loss.

Innovation Solution

The UE determines the channel busy ratio (CBR) to set a channel reservation limit, ensuring sufficient resources are reserved only for the initial transmission, thereby optimizing resource allocation and reducing the need for retransmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE reserves resources for both initial transmission and retransmission under congested conditions, then the reliability of message delivery is improved, but the spectral efficiency deteriorates due to insufficient available resources

Engineering Contradiction:
Improvemessage delivery reliabilityVSAvoidspectral efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the resource reservation strategy adaptive rather than static. The UE dynamically adjusts between reserving resources for retransmission and not reserving based on real-time channel conditions (CBR measurements). When CBR is below the threshold, the UE reserves resources for both initial transmission and retransmission. When CBR exceeds the threshold, the UE switches to reserving resources only for initial transmission, allowing the system to adapt to changing congestion levels and optimize the trade-off between reliability and spectral efficiency.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the UE reserves resources for retransmission, then the packet loss is reduced, but the available resources for other transmissions are depleted

Engineering Contradiction:
Improvepacket loss reductionVSAvoidresource utilization efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies parameter changes by modifying the resource reservation behavior based on the CBR parameter. The system changes the reservation parameter (whether to reserve retransmission resources) according to the measured channel conditions. This allows the system to optimize resource utilization efficiency by not reserving retransmission resources when the channel is congested, thereby making more resources available for other transmissions while maintaining acceptable reliability through the initial transmission reservation.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the UE determines channel reservation limit based on CBR, then the resource allocation is optimized, but the complexity of resource management increases

Engineering Contradiction:
Improveresource allocation efficiencyVSAvoidresource management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies self-service by enabling the UE to autonomously determine its own resource reservation limit based on its measurements of the channel busy ratio. The UE independently evaluates the CBR, compares it against the threshold, and decides whether to reserve resources for retransmission without requiring complex network coordination or external control. This self-service approach optimizes resource allocation efficiency while keeping the implementation relatively simple, as each UE makes independent decisions based on local observations.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4218290B1Resource selection under congested conditions
Publication Date: 2025.11.19 QUALCOMM INC
  • EP4218290B1 patent drawingFigure 1
  • EP4218290B1 patent drawingFigure 2
  • EP4218290B1 patent drawingFigure 3

AI summary

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may identify a message to be transmitted over a wireless channel, such as a vehicle-to-everything (V2X) system. The UE may determine a channel reservation limit for reserving resources on the wireless channel for the message based on a channel busy ratio for the wireless channel. The UE may determine that available resources are insufficient for both an initial transmission of the message and a retransmission of the message based on the channel reservation limit. The UE may reserve a resource on the wireless channel for the initial transmission of the message based on the available resources being insufficient for both the initial transmission of the message and the retransmission of the message.