TXOP Retransmission via Backoff Reset for WLAN Priority

Solution Overview

Problem

In wireless local area network (WLAN) systems, the conventional retransmission method during transmission opportunity (TXOP) sharing leads to inefficiencies due to secondary access category traffic being transmitted before primary AC traffic, resulting in continuous errors and frequent group ID changes, which reduces system performance, especially in high-density environments.

Innovation Solution

A method that includes transmitting an initial transmission frame with primary and secondary AC information, resetting the backoff timer for secondary AC information upon no response, and retransmitting based on the reset timer value, with independent retry counters for each AC and using an OFDMA transmission scheme to prioritize primary AC traffic, ensuring efficient retransmission and minimizing group ID changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional retransmission method is used during TXOP sharing, then secondary AC traffic can be transmitted, but primary AC traffic is transmitted after secondary AC causing continuous errors and frequent group ID changes

Engineering Contradiction:

Improvetransmission efficiencyVSAvoidtransmission reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by resetting the backoff timer for secondary AC information before attempting retransmission. This ensures that primary AC traffic is prioritized and transmitted first, preventing the scenario where secondary AC traffic is transmitted before primary AC traffic completes its transmission cycle, thereby eliminating continuous errors and frequent group ID changes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms by monitoring whether ACK is received for secondary AC information and using this feedback to determine whether to reset the backoff timer. This feedback loop ensures that retransmission occurs only when necessary and in the correct sequence, maintaining transmission reliability while optimizing productivity.

Inventive Principle:

Principle #23Feedback

2Productivity

If backoff timer is not reset for secondary AC information, then retransmission can proceed, but transmission failures increase due to incorrect priority ordering

Engineering Contradiction:

Improveretransmission speedVSAvoidtransmission success rate

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by resetting the backoff timer for secondary AC information before attempting retransmission. This ensures that primary AC traffic is prioritized and transmitted first, preventing the scenario where secondary AC traffic is transmitted before primary AC traffic completes its transmission cycle, thereby eliminating continuous errors and frequent group ID changes.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If group ID is frequently changed to accommodate retransmission, then transmission flexibility is maintained, but system overhead increases and performance decreases

Engineering Contradiction:

Improvetransmission flexibilityVSAvoidsystem overhead

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by resetting the backoff timer for secondary AC information before attempting retransmission. This ensures that primary AC traffic is prioritized and transmitted first, preventing the scenario where secondary AC traffic is transmitted before primary AC traffic completes its transmission cycle, thereby eliminating continuous errors and frequent group ID changes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the potential harm of transmission failures into a benefit by using the failure condition (no ACK received) as the trigger for resetting the backoff timer. This ensures that retransmission only occurs when necessary and in the correct sequence, reducing unnecessary group ID changes and system overhead while maintaining transmission flexibility.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS10201012B2Retransmission method at time of sharing transmission opportunity in wireless LAN system, and device therefor

Publication Date: 2019.02.05 LG ELECTRONICS INC

AI summary

The present document relates to a wireless communication system and, more particularly, to a method for performing retransmission in a wireless LAN system to which transmission opportunity (TXOP) sharing is applied, and a device therefor. To this end, a station transmits an initial transmission frame including primary access category (AC) information and secondary access category (AC) information; and when there is no response to the secondary AC information of the initial transmission frame, reconfigures a back-off timer value for the secondary AC information and retransmits the secondary AC information according to the reconfigured back-off timer value.