Sidelink Communication HARQ Feedback and Resource Pre-emption

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Solution Overview

Problem

Existing sidelink (SL) communication technologies, such as 3GPP Rel-12/Rel-13 D2D and Rel-14 V2V, are inefficient in resource utilization, throughput, QoS, reliability, complexity, and power consumption due to broadcast-based communication without feedback mechanisms, leading to wasted resources.

Innovation Solution

Implementing a mechanism for physical layer HARQ feedback procedure and resource pre-emption in SL communication, where Tx UE reserves resources for data and decoding result feedback, and Rx UE can pre-empt unused resources by sending a pre-emption indicator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If broadcast-based communication is used in SL communication, then coverage and reachability are improved, but resource utilization efficiency deteriorates due to wasted reserved resources

Engineering Contradiction:
Improvecoverage and reachabilityVSAvoidresource utilization efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent introduces feedback mechanisms where receiving UEs send decoding results back to transmitting UEs. This feedback enables transmitting UEs to identify when reserved resources are not needed (when decoding is successful) and can be pre-empted by other UEs, thus improving resource utilization efficiency while maintaining broadcast-based coverage

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements dynamic resource allocation through pre-emption mechanisms. Reserved resources that are not needed (identified via feedback) can be dynamically re-allocated to other UEs through pre-emption indicators. This transforms static reserved resources into dynamic, adaptable resources that respond to actual communication needs

Inventive Principle:
Principle #15Dynamics

2Device complexity

If blind (re)transmission without feedback is used, then system complexity is reduced, but throughput and reliability deteriorate

Engineering Contradiction:
Improvesystem complexityVSAvoidthroughput
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent introduces physical layer HARQ feedback procedures where receiving UEs transmit decoding results (ACK/NACK) to transmitting UEs. This feedback enables intelligent retransmission decisions, improving throughput and reliability while maintaining manageable system complexity through standardized feedback formats and procedures

Inventive Principle:
Principle #23Feedback

3Reliability

If reserved resources are allocated for SL data transmission, then QoS and reliability are improved, but resource utilization efficiency deteriorates when resources remain unused

Engineering Contradiction:
ImproveQoS and reliabilityVSAvoidresource utilization efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements a resource pre-emption mechanism where unused reserved resources (identified through feedback indicating successful decoding) can be pre-empted and re-allocated to other UEs. This allows the system to discard unused reservations and recover the resources for productive use, improving overall resource utilization efficiency while maintaining QoS for active transmissions

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentEP3858021B1Method and apparatus for sidelink communication
Publication Date: 2025.08.13 LENOVO (BEIJING) LTD
  • EP3858021B1 patent drawingFigure 1A
  • EP3858021B1 patent drawingFigure 1B
  • EP3858021B1 patent drawingFigure 2A

AI summary

Methods and apparatus for sidelink communication are disclosed. One method of a Tx/Rx UE comprises reserving resources for one or more sidelink (SL) data transmissions and resources for decoding result feedbacks corresponding to the one or more SL data transmissions; transmitting sidelink control information (SCI) to a second apparatus, which indicates the resources for the SL data transmissions; and receiving at least one of the decoding result feedback and a pre-emption indicator. Another method of a Tx/Rx UE comprises receiving SCI, which indicates resources for the SL data transmissions, from a first apparatus; and transmitting at least one of the decoding result feedback and a pre-emption indicator.