Sidelink HARQ Mode Switching for Mixed QoS Retransmission

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Solution Overview

Problem

Existing methods do not efficiently support hybrid automatic repeat request (HARQ) feedback-based and blind retransmission for the same sidelink logical channel in wireless communication systems, particularly in 5G networks, which are crucial for handling diverse quality of service (QoS) profiles.

Innovation Solution

A method and apparatus for a terminal to process HARQ feedback-based and blind retransmission in a mixed manner for the same sidelink logical channel, allowing the terminal to identify and apply appropriate HARQ retransmission modes based on configuration values without relying on HARQ feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If HARQ feedback-based retransmission is applied for sidelink logical channel, then reliability of data transmission is improved, but complexity of retransmission processing increases

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidretransmission processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the retransmission processing into two independent modes: HARQ feedback-based retransmission and blind retransmission. Each mode can be configured separately for different logical channels, allowing the system to process retransmissions in a divided manner rather than as a single complex unified process, thus reducing overall processing complexity while maintaining reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic configuration where the terminal can switch between HARQ feedback-based retransmission and blind retransmission modes based on real-time conditions. The terminal determines which mode to use by evaluating configuration information and channel conditions, enabling adaptive retransmission processing that adjusts complexity based on current network state.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If blind retransmission is applied for sidelink logical channel, then retransmission processing complexity is reduced, but data transmission reliability deteriorates

Engineering Contradiction:
Improveretransmission processing complexityVSAvoiddata transmission reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by enabling different retransmission modes for different logical channels based on their specific QoS requirements. Channels requiring high reliability can use HARQ feedback-based retransmission, while channels with lower reliability requirements can use blind retransmission. This localized approach optimizes the balance between complexity and reliability for each channel individually.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If multiple HARQ retransmission modes are supported for same logical channel, then adaptability to mixed QoS profiles is improved, but device complexity increases

Engineering Contradiction:
Improvesupport for mixed QoS profilesVSAvoidretransmission mode management complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements multi-functionality by enabling the terminal to support multiple HARQ retransmission modes (HARQ feedback-based and blind retransmission) within the same logical channel configuration. The terminal can apply different modes to different data flows or packets based on their QoS requirements, allowing a single logical channel to serve multiple QoS profiles simultaneously.

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

Solution Approach 2:

The patent uses parameter changes by configuring different retransmission mode parameters (such as maximum retransmission count, feedback timing, and mode switching conditions) to adapt the system behavior. By adjusting these parameters dynamically, the terminal can optimize performance for mixed QoS profiles without requiring fundamental architectural changes.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4135240B1Apparatus and method for processing sidelink HARQ retransmission procedure in wireless communication system
Publication Date: 2026.01.28 SAMSUNG ELECTRONICS CO LTD
  • EP4135240B1 patent drawingFigure 1
  • EP4135240B1 patent drawingFigure 2
  • EP4135240B1 patent drawingFigure 3

AI summary

The present disclosure relates to a technique for a sensor network, machine to machine (M2M) communication, machine-type communication (MTC) and the Internet of things (IoT). The present disclosure can be utilized in intelligent services (smart homes, smart buildings, smart cities, smart cars or connected cars, health care, digital education, retail business, security- and safety-related services, etc.) based on the technique. According to an embodiment of the present disclosure, provided is a method for a sidelink transmission UE in a communication system. The method comprises the steps of: receiving, from a base station, configuration information regarding a sidelink logical channel, the configuration information comprising information indicating to use hybrid automatic repeat request (HARQ) feedback-based retransmission and blind retransmission for the sidelink logical channel; when a medium access control (MAC) protocol data unit (PDU) to be transmitted is associated with the sidelink logical channel, determining any one of the HARQ feedback-based retransmission and the blind retransmission as a retransmission mode for the MAC PDU; verifying whether to retransmit the MAC PDU after transmitting the MAC PDU according to the retransmission mode; when it is verified to retransmit the MAC PDU, verifying whether to change the retransmission mode, on the basis of the configuration information; and when it is verified to change the retransmission mode, transmitting the MAC PDU, on the basis of the changed retransmission mode.