Access Point Channel Switching and Data Frame Loss Prevention

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Solution Overview

Problem

Data frames are lost due to channel switching in wireless local area network (WLAN) communications, as the access point fails to receive null data frames with power saving tags, leading to incorrect assumptions about the station's power save mode and subsequent data frame transmission.

Innovation Solution

The access point determines if it consistently fails to send data frames after channel switching by using a channel switching tag or variables, and if so, sends a wakeup signal to the station to prevent data frame loss by suspending and buffering data frames.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the access point switches channels temporarily to receive the null data frame, then the power save mode notification can be received, but the data frame transmission is delayed or lost

Engineering Contradiction:

Improvepower save mode notification receptionVSAvoiddata frame transmission delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The access point performs preliminary channel switching before the station sends the null data frame, so that the access point is already on the correct channel to receive the power save mode notification without delaying subsequent data frame transmissions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The access point monitors whether the station has entered power save mode by detecting the null data frame with power save tag, and uses this feedback information to adjust its channel switching behavior and data frame transmission timing

Inventive Principle:

Principle #23Feedback

2Productivity

If the access point sends data frame without confirming station's power save mode, then transmission speed is maintained, but data frame loss occurs

Engineering Contradiction:

Improvedata frame transmission speedVSAvoiddata frame delivery success

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The station autonomously manages its own power save state by sending the null data frame with power save tag, and the access point self-adjusts its transmission behavior based on detecting this signal, eliminating the need for complex handshaking protocols

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces complex mechanical channel switching and timing coordination with a simpler signal-based approach, where the power save tag in the null data frame serves as a direct indicator that substitutes for complex channel management mechanisms

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10542489B2Terminal wakeup method and apparatus

Publication Date: 2020.01.21 HUAWEI TECH CO LTD

AI summary

A terminal wakeup method and an apparatus are disclosed. The method includes: if an access point fails to send a data frame to a station, and the access point fails to send a data frame to the station after channel switching, sending, by the access point, a wakeup signal to the station to wake up the station. According to the method, a data frame loss caused by channel switching can be reduced.