TWT-Aware TCP Acknowledgment for Low-Power Wi-Fi Reliability

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Solution Overview

Problem

Low power Wi-Fi devices face complications when using the Target Wake Time (TWT) feature and delayed TCP acknowledgment, leading to potential TCP connection terminations due to large TWT wake intervals and delayed acknowledgments for 'keep alive' messages.

Innovation Solution

Implement a method where low power Wi-Fi devices check the payload size of incoming packets and transmit TCP acknowledgments immediately if the size is above or below predetermined thresholds, or delay the acknowledgment if within a specific range, ensuring they are sent during the same TWT service period.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If delayed TCP acknowledgment is used to optimize bandwidth, then energy consumption is reduced, but TCP connection reliability deteriorates due to large TWT wake intervals

Engineering Contradiction:

Improveenergy consumptionVSAvoidTCP connection reliability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent dynamically adjusts the TCP acknowledgment behavior based on the TWT wake interval duration. When the TWT wake interval is large, the system switches from delayed acknowledgment to immediate acknowledgment to ensure connection reliability. This dynamic adaptation resolves the contradiction by allowing the system to optimize for energy when appropriate while guaranteeing reliability when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the acknowledgment timing parameter based on the TWT configuration. By monitoring the TWT wake interval and adjusting the acknowledgment delay accordingly, the system can maintain TCP connection reliability while still benefiting from energy optimization in suitable scenarios.

Inventive Principle:

Principle #35Parameter changes

2Duration of action of moving object

If TWT wake interval is increased to extend sleep mode duration, then power saving is improved, but TCP connection maintenance deteriorates due to delayed acknowledgments

Engineering Contradiction:

Improvesleep mode durationVSAvoidTCP connection maintenance

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The system dynamically adjusts acknowledgment timing based on the TWT wake interval length. For large TWT intervals, immediate acknowledgment is used to maintain connections during extended sleep periods, while smaller intervals can utilize delayed acknowledgment for energy optimization.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements feedback mechanisms where the system monitors TWT configuration and connection status, then adjusts acknowledgment behavior accordingly. This feedback loop ensures that TCP connections are maintained reliably even during extended sleep modes enabled by large TWT intervals.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250247794A1Reliable TCP Data Transfer Using Target Wake Time (TWT)

Publication Date: 2025.07.31 SILICON LABORATORIES INC

AI summary

Methods and Wi-Fi devices that utilize the target wake time (TWT) feature of the Wi-Fi specification along with delayed TCP acknowledgment are disclosed. When using TWT and delayed TCP acknowledgment, the low power Wi-Fi device checks to see if the size of the payload is less than a predetermined value. By checking the size of the payload, the low power Wi-Fi device can quickly determine whether the received packet may be related to TCP connection/Application protocol connection maintenance. Based on this determination, if necessary, the low power Wi-Fi device can transmit an acknowledgment during the same TWT service period, thereby minimizing the chance that the TCP connection will be terminated.