Group DCI Feedback for URLLC PUSCH Reliability

Solution Overview

Problem

In the 3GPP R15 standard protocol, the reliability of Physical Uplink Shared Channel (PUSCH) transmission is low, leading to high miss detection probability, causing packet loss in Ultra-Reliable Low Latency Communication (URLLC) services due to the lack of explicit ACK feedback from the base station, which results in potential service interruptions.

Innovation Solution

A method and apparatus for transmitting group downlink control information (DCI) that includes N bit blocks carrying UE-ID, HARQ-ID, and bitmap mapping of HARQ processes, enabling explicit feedback indication to the user equipment (UE) to reduce miss detection and packet loss by using a predetermined sequence and resource allocation information during grant-free PUSCH transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the base station does not send explicit ACK feedback after correctly demodulating PUSCH data information, then the latency is reduced, but the reliability of PUSCH transmission deteriorates due to high miss detection probability

Engineering Contradiction:

ImprovelatencyVSAvoidPUSCH transmission reliability

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent implements explicit feedback mechanisms through group DCI format 0_2 and format 1_2 messages that carry ACK/NACK information for grant-free PUSCH transmissions. The base station sends group DCI messages containing feedback information for multiple UEs, allowing UEs to determine whether their PUSCH transmissions were successfully received without requiring individual ACK messages, thus maintaining low latency while improving reliability.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent combines feedback information for multiple UEs into a single group DCI message. The group DCI format 0_2 and format 1_2 messages contain feedback for multiple UEs simultaneously, merging what would otherwise be separate feedback transmissions into one unified message, reducing overall feedback latency while ensuring reliable delivery of acknowledgment information to all affected UEs.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If the base station sends explicit ACK feedback for each PUSCH transmission, then the reliability is improved, but the signaling overhead and latency increase

Engineering Contradiction:

ImprovePUSCH transmission reliabilityVSAvoidfeedback latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent combines feedback information for multiple UEs into a single group DCI message. The group DCI format 0_2 and format 1_2 messages contain feedback for multiple UEs simultaneously, merging what would otherwise be separate feedback transmissions into one unified message, reducing overall feedback latency while ensuring reliable delivery of acknowledgment information to all affected UEs.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The group DCI messages serve multiple functions simultaneously: they provide HARQ feedback for multiple UEs, carry resource allocation information, and enable UEs to determine whether retransmission is needed. This multi-functionality reduces the need for separate signaling messages, decreasing overall latency while maintaining comprehensive feedback coverage.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If individual ACK messages are sent to each UE, then the feedback precision is improved, but the device complexity and signaling overhead increase

Engineering Contradiction:

Improvefeedback precisionVSAvoidsignaling complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The group DCI message is segmented into distinct feedback fields for different UEs, with each UE's feedback information clearly demarcated within the group message. This segmentation allows UEs to efficiently extract their specific feedback information from the group message without processing entire individual ACK messages for all UEs, reducing computational complexity while maintaining precise feedback delivery.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent combines feedback information for multiple UEs into a single group DCI message. The group DCI format 0_2 and format 1_2 messages contain feedback for multiple UEs simultaneously, merging what would otherwise be separate feedback transmissions into one unified message, reducing overall feedback latency while ensuring reliable delivery of acknowledgment information to all affected UEs.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12004179B2Method and apparatus for transmitting group downlink control information

Publication Date: 2024.06.04 ZTE CORP

AI summary

Embodiments of the present disclosure provide a method and apparatus for transmitting group downlink control information (DCI), wherein the method includes: transmitting group DCI to a user side, wherein the group DCI includes N bit blocks, and each bit block carries indication information including at least one of: an identifier of a user to be fed back (UE-ID), an identifier of a Hybrid Automatic Repeat reQuest (HARQ) process (HARQ-ID) of the user to be fed back, and a bitmap mapping of K HARQ processes of one user; and the indication information carried in each bit block of the group DCI is configured to indicate feedback information of the corresponding HARQ process.