Grant-Free Transmission Feedback Using Pilot Sequence Bitmaps

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Solution Overview

Problem

In grant-free transmission modes of next-generation wireless communications, the inefficiency in using radio transmission resources for feedback due to the need for explicit user identity feedback reduces resource utilization, especially during massive user access scenarios.

Innovation Solution

A method where a network device uses a bitmap to indicate the feedback result of uplink transmissions based on pilot sequence indices, allowing for efficient radio resource usage by indicating acknowledgement (ACK) or negative acknowledgement (NACK) through fixed-length bit positions, reducing the need for explicit user identity feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If user identity is directly fed back to indicate successful transmission, then transmission feedback accuracy is improved, but resource utilization efficiency deteriorates due to excessive bits occupied by user identity

Engineering Contradiction:
Improvefeedback accuracyVSAvoidfeedback bit length
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts the user identity information from the feedback content and replaces it with a shortened identifier (such as a pointer or index). This allows the feedback to still identify the correct user equipment while occupying fewer bits, thus resolving the contradiction between feedback accuracy and resource efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the parameter of user identity representation from full-length identity information to a compressed form (shortened identifier, index, or pointer). This parameter transformation maintains the ability to identify the correct user while significantly reducing the bit length required for feedback transmission.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If grant-free transmission mode is used to support massive user access, then user access capacity is improved, but signaling overhead increases and transmission delay increases due to contention-based transmission

Engineering Contradiction:
Improveuser access capacityVSAvoidtransmission delay
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-configuring uplink transmission resources and pilot sequences for user equipment before actual data transmission. This allows user equipment to immediately transmit data without waiting for dynamic scheduling grants, thereby reducing transmission delay while supporting massive user access in grant-free mode.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3506538B1Method, network apparatus and terminal apparatus for grant-free transmission
Publication Date: 2021.06.16 HUAWEI TECH CO LTD
  • EP3506538B1 patent drawingFigure 1
  • EP3506538B1 patent drawingFigure 2
  • EP3506538B1 patent drawingFigure 3

AI summary

This application discloses a grant-free transmission method, a network device, and a terminal device. The method includes: detecting, by a network device, a pilot sequence used by a terminal device for uplink transmission; determining, by the network device, a pilot sequence index of the pilot sequence based on the pilot sequence and a correspondence between a pilot sequence and a pilot sequence index; and sending, by the network device, information about a feedback result of the uplink transmission to the terminal device based on the pilot sequence index. Therefore, the network device indicates the feedback result of the current uplink transmission to the terminal device by using the pilot sequence index, so as to efficiently use radio transmission resources to perform feedback on grant-free transmission of user equipment.