Multi-Link Wireless LAN Block ACK for Early Retransmission

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Solution Overview

Problem

In wireless LAN systems, especially with multi-link operations, the transmission-side communication device cannot identify data that needs retransmission until all data has been transmitted, leading to delayed identification and retransmission of undelivered data due to the inability to return a block ACK frame until the end of an A-MPDU frame.

Innovation Solution

The technology enables early identification of data requiring retransmission by transmitting a block ACK request frame in any appropriate frequency band, allowing the reception-side device to return a block ACK frame at any appropriate timing, including information on successful and unsuccessful data reception across multiple frequency bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If frame aggregation is performed to transmit multiple MPDUs in a single A-MPDU frame, then transmission efficiency is improved, but the reception-side device cannot return a block ACK frame until the end of the A-MPDU frame arrives, causing delayed identification of undelivered data

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidtime to identify undelivered data
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent divides the acknowledgment process into segments by allowing intermediate block ACK frames to be returned during A-MPDU transmission. Instead of waiting for the complete A-MPDU, the receiver can return block ACK frames at intermediate points, enabling the transmitter to identify undelivered data earlier while maintaining the efficiency benefits of frame aggregation.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the block ACK frame is returned only after the end of A-MPDU frame arrives, then acknowledgment accuracy is ensured, but retransmission timing is delayed

Engineering Contradiction:
Improveacknowledgment accuracyVSAvoidretransmission timing
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent enables preliminary acknowledgment by allowing the receiver to return block ACK frames before the A-MPDU transmission is complete. This preliminary action provides early feedback on received data status, enabling the transmitter to prepare for retransmission earlier while maintaining accurate acknowledgment information.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If all data must be transmitted before identifying undelivered data, then complete transmission status is confirmed, but overall transmission time increases

Engineering Contradiction:
Improvetransmission status confirmationVSAvoidoverall transmission time
Core Design Contradiction:
Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The patent implements continuous feedback during A-MPDU transmission by allowing intermediate block ACK frames to be returned. This feedback mechanism provides real-time information about which data units have been successfully received, enabling the transmitter to identify undelivered data earlier and initiate retransmission without waiting for complete transmission.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4287735B1Communication device and communication method
Publication Date: 2025.10.29 SONY GROUP CORP
  • EP4287735B1 patent drawingFigure 1
  • EP4287735B1 patent drawingFigure 2
  • EP4287735B1 patent drawingFigure 3

AI summary

The present technology relates to a communication device that enables identifying of data that needs to be retransmitted at an early stage, and a communication method. The communication device includes a control unit that performs control to: exchange frames with another communication device by wireless communication using a plurality of links; when transmitting a data frame including aggregated data using a first link, transmit an acknowledgment request frame for the data, using a second link; and receive an acknowledgment frame in response to the acknowledgment request frame from the another communication device that has received the data frame. The present technology can be applied to communication devices that constitute a wireless LAN system, for example.