Uplink HARQ Explicit Feedback for NOMA Resource Sharing

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Solution Overview

Problem

The existing HARQ operation in NR networks, particularly for uplink data transmissions with non-orthogonal multiple access (NOMA), lacks robustness and explicit feedback, leading to inefficiencies and increased probability of conflicts and failed transmissions.

Innovation Solution

Implementing explicit HARQ feedback for uplink data transmissions by associating HARQ process IDs with both time resources and UE-specific signatures, allowing for improved reception status indication and resource management in NOMA scenarios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If implicit HARQ feedback is used for UL data transmission, then device complexity is reduced, but reliability deteriorates due to lack of explicit feedback

Engineering Contradiction:
ImproveHARQ operation robustnessVSAvoidHARQ feedback mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces explicit HARQ feedback feedback mechanism where the network node sends feedback information to the terminal device about the reception status of UL data transmission. This feedback can indicate successful reception, failed reception, or no transmission detected, enabling the terminal to adjust its behavior accordingly and improving overall system reliability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent segments the HARQ feedback into different types: positive feedback for successful reception, negative feedback for failed reception, and DTX indication for no transmission. This segmentation allows for more precise control and management of retransmission processes, improving reliability without requiring a completely new complex system.

Inventive Principle:
Principle #1Segmentation

2Productivity

If multiple UEs share overlapping uplink resources using NOMA, then productivity increases, but reliability deteriorates due to increased transmission conflicts

Engineering Contradiction:
ImproveUE throughputVSAvoidTransmission success rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces a new dimension to HARQ feedback by associating feedback with specific signatures or resource indicators that identify which UE's transmission was received. This allows the system to maintain NOMA's high productivity while providing UE-specific feedback, enabling reliable retransmission control even when multiple UEs share resources.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent applies local quality by providing feedback specific to each UE's transmission within the shared resource. Instead of a single feedback for all UEs, each UE receives feedback related to its specific transmission, allowing individual reliability management while maintaining the benefits of resource sharing.

Inventive Principle:
Principle #3Local quality

3Reliability

If HARQ process ID is determined based solely on time resources, then device complexity is reduced, but reliability deteriorates in NOMA scenarios

Engineering Contradiction:
ImproveHARQ process identification accuracyVSAvoidHARQ process ID determination complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple identification parameters (time resource, signature, and/or resource indicator) to determine the HARQ process ID. This combination provides more accurate identification of which UE's transmission needs feedback, improving reliability in NOMA scenarios while the merging approach keeps the determination mechanism manageable.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces signature or resource indicator as intermediary elements that link the time resource to the specific UE. These intermediaries enable reliable HARQ process identification without requiring direct complex interactions between all parameters, simplifying the overall determination mechanism while improving accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3857997B1Method and apparatus for optimized HARQ operation
Publication Date: 2025.09.10 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3857997B1 patent drawingFigure 1
  • EP3857997B1 patent drawingFigure 2
  • EP3857997B1 patent drawingFigure 3~5

AI summary

Various embodiments of the present disclosure provide a method for optimized HARQ operation. The method comprises transmitting an uplink data transmission on the shared uplink resource to a network node, and receiving a feedback message from the network node, the feedback message comprising a feedback indication indicating a reception status of the uplink data transmission from the terminal device. According to the embodiments of the present disclosure, the explicit HARQ feedback can be provided for uplink data transmission in a wireless communication network such as NR network.