Dynamic HARQ Feedback Channel Selection for URLLC Puncturing

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Solution Overview

Problem

In wireless communication networks, the fixed HARQ feedback timing in LTE systems can lead to inefficiencies and reliability issues, especially when dealing with URLLC traffic, as it does not provide clear feedback on the decoding status of URLLC data punctured within eMBB transmissions, resulting in potential re-transmissions and performance degradation.

Innovation Solution

Implementing a method to select and configure HARQ feedback channels for both eMBB and URLLC data, allowing for options such as using only a slot-based channel, a mini-slot-based channel, or both for feedback, to improve latency and control channel overhead, enabling clear acknowledgement of both data types and facilitating re-transmissions as needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If fixed HARQ feedback timing is used in LTE systems, then system simplicity is maintained, but feedback reliability and latency performance deteriorate for URLLC traffic

Engineering Contradiction:
Improvesystem simplicityVSAvoidfeedback reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces dynamic HARQ feedback timing mechanisms that adapt to different traffic types (eMBB vs URLLC). The system dynamically selects between slot-based and mini-slot-based feedback channels based on the punctured traffic type, enabling flexible adjustment of feedback timing to meet varying reliability and latency requirements while maintaining system simplicity through standardized procedures.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the feedback timing parameter by introducing different feedback options (slot-based vs mini-slot-based) depending on the traffic type. For URLLC punctured in eMBB, the system can select mini-slot-based feedback to reduce latency and improve reliability, while for non-punctured eMBB traffic, slot-based feedback maintains simplicity. This parameter change resolves the contradiction between system simplicity and feedback reliability.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If fixed HARQ feedback timing is used, then implementation ease is maintained, but latency performance deteriorates for punctured URLLC data

Engineering Contradiction:
Improveimplementation easeVSAvoidfeedback latency
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The system dynamically adjusts feedback timing based on traffic type. When URLLC is punctured in eMBB transmissions, the system switches to mini-slot-based feedback channels that provide faster feedback with reduced latency. This dynamic adjustment maintains implementation ease through standardized procedures while significantly reducing feedback latency for time-sensitive URLLC traffic.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent segments the feedback mechanism into different channels: slot-based feedback channels for eMBB traffic and mini-slot-based feedback channels for URLLC traffic. This segmentation allows each channel to be optimized for its specific traffic type, with mini-slot channels providing faster feedback for URLLC while slot channels maintain simplicity for eMBB, thus reducing overall feedback latency without compromising implementation ease.

Inventive Principle:
Principle #1Segmentation

3Quantity of substance

If single feedback channel is used for both eMBB and URLLC, then channel overhead is reduced, but feedback precision deteriorates

Engineering Contradiction:
Improvecontrol channel overheadVSAvoidfeedback precision
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent segments the feedback mechanism into separate channels: slot-based feedback channels for eMBB traffic and mini-slot-based feedback channels for URLLC traffic. This segmentation enables precise feedback for each traffic type on dedicated channels, improving feedback precision by matching channel characteristics to traffic requirements while managing overhead through selective usage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system applies different feedback channel qualities to different traffic types: mini-slot-based channels provide faster, more precise feedback for URLLC traffic requiring low latency, while slot-based channels provide adequate feedback for eMBB traffic. This local quality differentiation improves overall feedback precision by optimizing each channel's characteristics for its intended traffic type while controlling total overhead.

Inventive Principle:
Principle #3Local quality

4Productivity

If puncturing is used to transmit URLLC in eMBB resources, then resource utilization improves, but feedback clarity deteriorates

Engineering Contradiction:
Improveresource utilizationVSAvoidfeedback clarity
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent segments the feedback mechanism to provide separate feedback channels for punctured URLLC traffic and non-punctured eMBB traffic. By using mini-slot-based feedback channels specifically for punctured URLLC transmissions, the system maintains clear feedback information that identifies whether URLLC data was successfully decoded, preventing feedback confusion while maintaining high resource utilization through puncturing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements enhanced feedback mechanisms that provide explicit acknowledgment of punctured URLLC data decoding status. The feedback includes clear indicators that distinguish between eMBB and URLLC decoding outcomes, ensuring feedback clarity even when URLLC is punctured in eMBB resources. This maintains resource utilization efficiency while preventing information loss in the feedback loop.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3603256B1Network node and method in a wireless communications network
Publication Date: 2020.05.13 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3603256B1 patent drawingFigure 1
  • EP3603256B1 patent drawingFigure 2
  • EP3603256B1 patent drawingFigure 3

AI summary

A method performed by a network node (110) for deciding a feedback option of a message sent between the network node (110) and a User Equipment, UE, 120 in a wireless communication network (100) is provided. The message comprises a first data, which is punctured by a second data. The first data is sent in a slot of a radio resource. The second data is sent a mini-slot of the radio resource. The mini-slot is smaller than the slot. The network node (110) decides (401) a feedback option for feedback that is to be sent to the sender of the message. The deciding is based on any one or more out of: slot control resource capacity, mini-slot control resource capacity and requirements of the radio bearer. The feedback option may relate to any one out of: (1) Only a slot based channel is used for feedback of both the first data and the second data, (2) a mini-slot based channel is used for feedback of the second data and a slot based channel is used for feedback of the first data, and (3) only a mini-slot based channel is used for feedback of both the first data and the second data.