Asynchronous HARQ Feedback Resource Selection in Sidelink

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Solution Overview

Problem

Existing wireless communication systems face inefficiencies in sidelink communication feedback, particularly in selecting appropriate resources for transmitting hybrid automatic repeat request (HARQ) feedback, leading to increased latency and potential congestion.

Innovation Solution

The implementation of a framework that allows user equipment (UE) to select sidelink shared channel resources for transmitting HARQ feedback based on conditions such as priority, availability, and channel sensing, enabling efficient resource allocation and reduced latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sidelink feedback channel resources are used for HARQ feedback transmission, then feedback reliability is improved, but resource availability and flexibility are reduced

Engineering Contradiction:

Improvefeedback reliabilityVSAvoidresource availability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The PSSCH is designed to serve dual purposes: transmitting data and transmitting HARQ feedback. By enabling the shared channel to function as both a data channel and a feedback channel under certain conditions, the system achieves flexibility in resource allocation while maintaining feedback transmission capability. The UE selects to use PSSCH for feedback when it determines the resource is available and appropriate, thereby adapting the resource usage dynamically.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system implements dynamic resource selection where the UE can choose between PSFCH and PSSCH for HARQ feedback transmission based on real-time conditions. The selection is not fixed but adapts to channel state, resource availability, and traffic requirements, allowing the system to optimize feedback transmission resources dynamically rather than following a rigid predetermined pattern.

Inventive Principle:

Principle #15Dynamics

2Reliability

If dedicated sidelink feedback channel resources are allocated, then feedback transmission reliability is improved, but system resource efficiency deteriorates

Engineering Contradiction:

Improvefeedback transmission reliabilityVSAvoidsystem resource efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges the data transmission function and feedback transmission function into a single channel (PSSCH). By combining these two functions that were previously separated into different channels, the system reduces overall resource consumption while maintaining the ability to transmit feedback reliably when needed. The UE can multiplex feedback information with data on the same PSSCH resources.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The system enables UEs to autonomously select appropriate feedback transmission resources based on their own needs and channel conditions. The UE performs self-service by determining whether to use PSSCH or PSFCH for feedback transmission, eliminating the need for centralized resource allocation and improving overall system resource efficiency while maintaining reliability.

Inventive Principle:

Principle #25Self-service

3Device complexity

If synchronous HARQ feedback is used, then feedback timing is standardized, but latency increases for asynchronous traffic patterns

Engineering Contradiction:

Improvefeedback timing standardizationVSAvoidlatency

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The system implements dynamic feedback timing where the UE can transmit HARQ feedback asynchronously based on when the feedback information is ready, rather than adhering to fixed synchronous timing. This allows the feedback transmission to adapt to the actual data reception timing and processing requirements, reducing latency for asynchronous traffic patterns while maintaining flexibility in timing.

Inventive Principle:

Principle #15Dynamics

4Adaptability or versatility

If multiple feedback channel options are provided, then resource flexibility is improved, but selection complexity increases

Engineering Contradiction:

Improveresource flexibilityVSAvoidselection complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of providing complex selection mechanisms and multiple dedicated feedback channels, the patent inverts the approach by enabling the data channel (PSSCH) to carry feedback information. This simplifies the feedback resource selection by utilizing existing data channel resources that are already allocated, thereby reducing selection complexity while maintaining resource flexibility.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS20240406976A1Asynchronous hybrid automatic repeat request (HARQ) feedback for sidelink

Publication Date: 2024.12.05 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communication are described. A first user equipment (UE) may receive a sidelink message from a second UE via one or more sidelink resources. The first UE may select a sidelink shared channel resource to use for transmission of feedback information associated with the sidelink message. The selecting may be based on one or more conditions and may be between the sidelink shared channel resource and a sidelink feedback channel resource. The first UE may transmit the feedback information to the second UE via at least the sidelink shared channel resource.