Autonomous Sidelink Feedback Resource Allocation for V2X

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Solution Overview

Problem

Current sidelink radio communication techniques for vehicle-to-everything (V2X) applications face challenges in meeting high reliability and low latency requirements, particularly in unicast and feedback-based transmissions, as they rely on centralized scheduling and additional signaling with the radio access network, which can increase latency and reduce spectral efficiency.

Innovation Solution

A method for sidelink radio communication that allows for autonomous determination of feedback radio resources by the transmitting and receiving devices, enabling unicast mode transmissions and feedback control without relying on centralized scheduling, thus reducing latency and improving reliability by allowing feedback-controlled transmissions and adaptive modulation/coding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If centralized scheduling with RAN node is used to allocate feedback channel resources, then resource allocation control is improved, but latency increases and reliability decreases due to additional signaling requirements

Engineering Contradiction:
Improveresource allocation controlVSAvoidlatency
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The transmitting UE autonomously determines feedback channel resources without RAN node involvement. The UE selects resources from a pre-configured set based on its own transmission parameters, eliminating the need for centralized scheduling and reducing signaling latency.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

A set of feedback channel resources is pre-configured in the UE before communication begins. This preliminary preparation allows the UE to immediately select appropriate feedback resources without waiting for RAN node allocation decisions, reducing latency while maintaining controlled resource usage.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If blind retransmission is used for unicast sidelink communication, then reliability is improved through multiple transmission attempts, but spectral efficiency decreases due to repeated transmissions without feedback

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidspectral efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The receiving UE sends feedback signals (ACK/NACK) to the transmitting UE on pre-configured feedback channel resources. This feedback mechanism allows the transmitting UE to determine whether retransmission is necessary, improving spectral efficiency by avoiding unnecessary blind retransmissions while maintaining reliability through targeted retransmission when needed.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If RAN node involvement is required for feedback channel allocation, then resource management control is improved, but device complexity increases due to additional signaling protocols and procedures

Engineering Contradiction:
Improveresource management controlVSAvoidsignaling complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The UE independently determines feedback channel resources using pre-configured parameters and its own transmission information, eliminating the need for complex signaling protocols with the RAN node. This self-service approach reduces device complexity while maintaining controlled resource allocation through pre-planned resource sets.

Inventive Principle:
Principle #25Self-service

4Loss of time

If autonomous resource selection by transmitting device is used, then latency is reduced by eliminating centralized scheduling, but resource allocation control worsens without coordinated management

Engineering Contradiction:
ImprovelatencyVSAvoidresource allocation control
Core Design Contradiction:
Loss of timeVSEase of operation

Solution Approach 1:

The pre-configured feedback channel resources serve multiple purposes: they provide autonomous selection capability for low latency, while also enabling controlled resource management through pre-planned allocation. The same resource set supports both independent UE selection and systematic resource management without requiring real-time coordination.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3777382B1Technique for sidelink feedback transmissions
Publication Date: 2022.07.13 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3777382B1 patent drawingFigure 1~2
  • EP3777382B1 patent drawingFigure 3
  • EP3777382B1 patent drawingFigure 4

AI summary

A technique for transmitting and receiving data (602) using a sidelink, SL, radio communication (604) between a first radio device (100) and a second radio device (200) is described. As to one method aspect of the technique, a scheduling assignment, SA (601), announcing a transmission of the data (602) for the second radio device (200) is broadcasted. The data is transmitted according to the SA (601) from the first radio device (100) in a unicast mode to the second radio device (200). Responsive to the data transmission, a control feedback (608) is received from the second radio device (200) in a unicast mode at the first radio device (100), wherein the control feedback (608) is received on a feedback radio resource (708) determined by at least one of the first radio device (100) and the second radio device (200).