Semi-Persistent Scheduling Acknowledgment Feedback Mechanism

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Solution Overview

Problem

In 5G mobile communications, particularly for the ultra-reliable and low-latency communication (URLLC) service, there is a challenge in ensuring latency and reliability while reducing signaling overheads, especially in feeding back acknowledgment information from the receive end.

Innovation Solution

The proposed solution involves using semi-persistent scheduling (SPS) technology, where the terminal device determines a time unit offset to feed back acknowledgment information, allowing for efficient acknowledgment codebook formation and transmission on specific time-frequency resources, thereby optimizing acknowledgment information feedback without increasing latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If semi-persistent scheduling (SPS) technology is used to send data, then data transmission efficiency is improved and signaling overheads are reduced, but there is no corresponding solution for how the receive end feeds back acknowledgment data

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidacknowledgment feedback mechanism completeness
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the acknowledgment feedback process by introducing separate feedback mechanisms for different data types. Dynamic scheduling data uses traditional per-packet acknowledgment, while semi-persistent scheduled data uses batched periodic acknowledgment. This segmentation allows the system to maintain simple feedback for SPS data while handling dynamic data individually, resolving the contradiction between efficiency and completeness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements periodic acknowledgment feedback for semi-persistent scheduled data, where the receive end sends batched acknowledgment information at predetermined intervals rather than for every individual packet. This periodic action reduces signaling overhead while maintaining reliable feedback for SPS data, addressing the gap in the original SPS mechanism.

Inventive Principle:
Principle #19Periodic action

2Reliability

If traditional acknowledgment feedback is used for each downlink data packet, then reliability is improved, but signaling overheads increase

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent merges multiple acknowledgment bits for semi-persistent scheduled data into a single batched feedback message sent at periodic intervals. Instead of transmitting separate acknowledgment signals for each SPS data packet, the system combines them into consolidated feedback, significantly reducing signaling overhead while preserving complete reliability information for all SPS transmissions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

By implementing periodic batched acknowledgment feedback for SPS data, the system reduces the frequency of signaling transmissions while maintaining comprehensive reliability monitoring. The periodic feedback captures the status of multiple packets in each cycle, achieving both reduced overhead and preserved reliability.

Inventive Principle:
Principle #19Periodic action

3Quantity of substance

If batched acknowledgment feedback is used for semi-persistent scheduled data, then signaling overheads are reduced, but feedback latency may increase

Engineering Contradiction:
Improvesignaling overheadVSAvoidfeedback latency
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent segments the feedback system into two parallel paths: frequent low-latency feedback for dynamic scheduling data and periodic batched feedback for SPS data. This segmentation ensures that time-critical dynamic data receives immediate acknowledgment while SPS data benefits from reduced overhead, preventing batched feedback from increasing overall system latency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically selects different feedback strategies based on data type and urgency. For time-sensitive dynamic scheduling data, traditional immediate feedback is used. For less time-critical SPS data, periodic batched feedback is applied. This dynamic approach optimizes the balance between overhead reduction and latency requirements for different traffic types.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3823383B1Communication method and device
Publication Date: 2025.03.26 HUAWEI TECH CO LTD
  • EP3823383B1 patent drawingFigure 1
  • EP3823383B1 patent drawingFigure 2
  • EP3823383B1 patent drawingFigure 3~4

AI summary

A communication method and a communications apparatus are provided. A principle of the method is as follows: Currently, for downlink data transmitted in a semi-persistent scheduling manner, only 1-bit acknowledgment information can be fed back in one time unit. However, as a transmission periodicity P of the downlink data transmitted in the semi-persistent scheduling manner becomes smaller, multi-bit acknowledgment information may need to be fed back in one time unit. In view of this, this application provides a communication method and a communications apparatus, mainly to feed back multi-bit acknowledgment information in one time unit. A main principle is as follows: First, multi-bit acknowledgment information to-be-sent in one time unit is determined; then N acknowledgment codebooks are generated, where the N acknowledgment codebooks are used to carry the multi-bit acknowledgment information; and finally, the N acknowledgment codebooks are sent in the time unit.