Sidelink Carrier Selection Using Receiver CBR Feedback

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Solution Overview

Problem

Current carrier selection methods in sidelink communication, such as Mode 2 in 3GPP, focus on CBR measurements at the transmitting terminal device and do not consider interference/congestion conditions at the receiving terminal device, leading to suboptimal carrier choices that can exacerbate congestion.

Innovation Solution

Implement a method where terminal devices exchange CBR information and adjust carrier selection based on mutual measurements and feedback, such as ACK/NACK messages, to align carrier choices and minimize interference at both ends.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If carrier selection is based only on CBR measurements at the transmitting terminal device, then the selection process is simple, but interference conditions at the receiving terminal device are not considered leading to suboptimal carrier choices

Engineering Contradiction:
Improvecarrier selection processVSAvoidcarrier selection optimality
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements feedback by having the receiving terminal device send CBR measurement information back to the transmitting terminal device. This allows the transmitting device to make carrier selection decisions based on both its own CBR measurements and the receiving device's perspective, thereby resolving the contradiction between simple operation and optimal selection.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses CBR measurement information as an intermediary to bridge the knowledge gap between transmitting and receiving devices. This intermediary information enables the transmitting device to infer receiving conditions without direct measurement, achieving better carrier selection while maintaining operational simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If terminal devices use different carriers for transmission based on their own CBR measurements, then each device optimizes its own transmission, but congestion is exacerbated due to lack of coordination

Engineering Contradiction:
Improveindividual transmission optimizationVSAvoidcongestion
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent merges the carrier selection decisions of transmitting and receiving devices by having them exchange CBR information and coordinate their choices. This combination of both devices' perspectives prevents the harmful effect of uncoordinated carrier selection that would otherwise exacerbate congestion.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

By implementing feedback loops where receiving devices report CBR measurements to transmitting devices, the system enables coordinated carrier selection. This feedback mechanism allows both devices to optimize transmission simultaneously while avoiding the congestion that arises from independent, uncoordinated decisions.

Inventive Principle:
Principle #23Feedback

3Reliability

If carrier selection considers interference conditions at both transmitting and receiving devices, then communication efficiency is improved, but the complexity of the selection process increases

Engineering Contradiction:
Improvecarrier selection optimalityVSAvoidcarrier selection process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses CBR measurement information as an intermediary that simplifies the complexity issue. Instead of requiring complex direct measurement and analysis at both ends, the intermediary CBR data enables both devices to assess interference conditions with relatively simple procedures, achieving optimal carrier selection without excessive complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4173393B1Enhanced carrier selection
Publication Date: 2026.04.01 NOKIA TECHNOLOGIES OY
  • EP4173393B1 patent drawingFigure 1~2
  • EP4173393B1 patent drawingFigure 3~8
  • EP4173393B1 patent drawingFigure 4

AI summary

Apparatus and method in a communication system for enhanced carrier selection are provided. The solution comprises selecting (300) a carrier for first transmission to a second apparatus; controlling transmission (302) utilising the selected carrier; receiving (304) a transmission from the second apparatus and selecting (306) a carrier for second transmission to the second apparatus at least partly based on the transmission from the second apparatus.