HARQ Retransmission Diversity Distance Control

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Solution Overview

Problem

Current group transmission techniques in D2D communications, such as autonomous retransmissions, face challenges in ensuring reliable transmission while minimizing unnecessary retransmissions and managing varying radio link conditions among UEs, leading to inefficiencies and increased delays in 5G networks with higher frequencies.

Innovation Solution

A method where a network node adjusts the number of HARQ retransmissions and diversity distance based on received feedback quality, increasing retransmissions when quality is low and decreasing when quality is high, to optimize success rates and reduce delays, while also selecting UEs for feedback to minimize signaling overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If autonomous retransmissions are used in group transmission, then transmission reliability is improved, but unnecessary retransmissions increase and delays are extended

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidend-to-end delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements feedback mechanisms where UEs report channel quality information (CQI) and HARQ acknowledgments to the network node. This feedback enables the network node to make informed decisions about retransmissions, adjusting the number of retransmissions and diversity distance based on actual channel conditions rather than using fixed autonomous retransmission schemes.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts transmission parameters including the number of HARQ retransmissions and diversity distance based on real-time channel conditions. The network node modifies these parameters adaptively according to CQI reports and HARQ feedback from UEs, transitioning from static autonomous retransmissions to dynamic controlled retransmissions that optimize both reliability and delay.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the number of HARQ retransmissions is increased to improve reliability, then transmission success rate improves, but resource consumption increases

Engineering Contradiction:
Improvetransmission success rateVSAvoidresource consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes transmission parameters including the number of HARQ retransmissions, diversity distance, and modulation and coding schemes based on channel conditions. The network node adjusts these parameters dynamically to achieve reliable transmission while minimizing resource consumption, rather than using fixed high retransmission counts.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Through CQI reports and HARQ feedback from UEs, the network node receives information about channel quality and transmission success. This feedback enables intelligent adjustment of retransmission parameters, increasing retransmissions only when necessary and reducing them when channel conditions are good, thereby optimizing resource consumption.

Inventive Principle:
Principle #23Feedback

3Reliability

If diversity distance is increased to improve transmission reliability, then robustness against fading improves, but transmission delay increases

Engineering Contradiction:
Improverobustness against fadingVSAvoidtransmission delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent dynamically adjusts diversity distance based on channel conditions and transmission requirements. The network node modifies diversity distance adaptively rather than using fixed large values, increasing it when fading conditions are severe and reducing it when conditions are favorable, thereby balancing robustness and delay.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the diversity distance parameter along with other transmission parameters like HARQ retransmission count and modulation schemes. This coordinated parameter adjustment allows the system to achieve required reliability through multiple mechanisms rather than relying solely on increased diversity distance, thereby reducing delay.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If feedback from all UEs is collected for HARQ control, then transmission reliability improves, but signaling overhead increases

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts and processes only the essential feedback information from UEs, such as CQI reports and HARQ acknowledgments, rather than collecting and processing all possible feedback data. The network node uses this condensed feedback to make transmission decisions, reducing signaling overhead while maintaining reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements partial feedback collection where not all UEs provide feedback for every transmission. Instead, the network node collects feedback from a subset of UEs or only when necessary, reducing signaling overhead while still achieving sufficient information for reliable transmission control.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3476069B1Methods and apparatuses for group transmissions
Publication Date: 2020.05.06 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3476069B1 patent drawingFigure 1
  • EP3476069B1 patent drawingFigure 2
  • EP3476069B1 patent drawingFigure 3

AI summary

The embodiments herein relates to a network node (110000); a UE (1600) and methods thereof for reliable group transmissions. The method in the UE comprises receiving from a network node, at least one signaling comprising HARQ parameters including a diversity distance i.e. a number of TTIs, between a HARQ transmission and a subsequent HARQ re-transmission and information on a number of retransmissions; receiving at least one transmission comprising at least one packet from the network node; decoding the received at least one packet; if the decoding of the at least one packet is successful; encoding the at least one packet and retransmitting, to at least one other UE of the group, the at least one transmission including the at least one encoded packet, wherein retransmitting of the at least one packet is performed simultaneously as retransmission of the at least one transmission from the network node to the at least one other UE of the group.