Sidelink HARQ Feedback Aggregation Across Multiple SL Carriers

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Solution Overview

Problem

Current SL communications technology lacks efficient solutions for implementing SL CA with SL HARQ feedback procedures, particularly in terms of organizing PSFCH resources for HARQ feedback and mapping them to SL CA resources, especially in unicast and groupcast scenarios.

Innovation Solution

The techniques enable UEs to perform HARQ procedures through aggregated SL carriers using a single SL carrier (PSFCH) for SL HARQ feedback, determining the PSFCH primary cell based on pre-defined rules, resource pool configurations, or dynamic indications, and mapping multiple SL carriers to specific PSFCH resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple SL carriers are used for data transmission, then data transmission capacity is improved, but the complexity of organizing and mapping PSFCH resources for HARQ feedback increases

Engineering Contradiction:

Improvedata transmission capacityVSAvoidPSFCH resource organization complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent merges feedback for multiple SL carriers into a single PSFCH resource. Specifically, multiple component carriers (CCs) are mapped to a single PSFCH resource for HARQ-ACK feedback, reducing the number of feedback resources needed. This is achieved by determining a single PSFCH resource index based on the lowest CC index among the aggregated carriers, thereby simplifying resource organization while maintaining multi-carrier transmission capacity.

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If separate PSFCH resources are allocated for each SL carrier, then feedback precision is improved, but resource overhead and system complexity increase

Engineering Contradiction:

ImproveHARQ feedback precisionVSAvoidPSFCH resource overhead

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent makes a single PSFCH resource serve multiple SL carriers simultaneously. The determined PSFCH resource functions as a universal feedback channel for all aggregated carriers, eliminating the need for separate dedicated resources per carrier. This multi-functional approach reduces resource overhead while maintaining the ability to provide precise HARQ feedback for each carrier through the unified resource.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If SL HARQ feedback procedures are implemented without aggregation, then implementation simplicity is improved, but communication efficiency for carrier aggregation scenarios deteriorates

Engineering Contradiction:

Improveimplementation simplicityVSAvoidcommunication efficiency

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent segments the carrier aggregation scenario into two distinct parts: data transmission occurs across multiple SL carriers while feedback is consolidated on a single carrier. This segmentation allows the system to maintain the benefits of multi-carrier transmission for data throughput while using a single-carrier feedback mechanism for simplicity. The feedback for all aggregated carriers is transmitted through one PSFCH resource on a designated carrier, thus preserving implementation simplicity while enabling efficient carrier aggregation.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250343632A1Systems, methods, and devices for aggregated sidelink feedback

Publication Date: 2025.11.06 APPLE INC

AI summary

Techniques, described herein, may enable a user equipment (UE) to use multiple sidelink (SL) carriers to send information to another UE, and for feedback regarding reception of the information to be communicated via a single SL carrier.