NDP Probe Request Scanning for WLAN Power Reduction

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Solution Overview

Problem

In M2M communication within WLAN systems, the increasing number of devices leads to prolonged channel access times, deteriorating system performance and hindering power saving, as existing scanning methods are inefficient and consume excessive power.

Innovation Solution

A method involving the transmission of a null data packet (NDP) probe request frame with a compressed SSID field, allowing for efficient scanning by recognizing the presence of access points (APs) with minimal power consumption, using a compressed SSID field and access network option field to reduce scanning overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional scanning methods are used in WLAN systems with many devices, then channel access can be established, but scanning time increases and power consumption increases

Engineering Contradiction:
Improvechannel access capabilityVSAvoidscanning time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts the essential scanning function by using NDP (Null Data Packet) probe request frames that contain only the necessary compressed SSID information, eliminating unnecessary scanning overhead and reducing scanning time while maintaining reliable channel access detection

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the scanning parameters by using compressed SSID fields and NDP frames with modified frame structures, allowing faster processing and reduced scanning duration without compromising the ability to identify available channels

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional scanning methods are used in WLAN systems with many devices, then channel access can be established, but power consumption increases

Engineering Contradiction:
Improvechannel access capabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential scanning functionality using compressed SSID fields and NDP frames, removing unnecessary scanning operations that consume power, thereby reducing overall power consumption while maintaining reliable channel access detection

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements periodic scanning at optimized intervals using NDP probe request frames, allowing the device to scan only when necessary rather than continuously, which reduces power consumption while ensuring channel access capability is maintained

Inventive Principle:
Principle #19Periodic action

3Quantity of substance

If the number of devices increases in WLAN system, then network capacity increases, but channel access time for each device increases

Engineering Contradiction:
Improvenumber of devicesVSAvoidchannel access time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent extracts the critical scanning function using efficient NDP probe request frames with compressed SSIDs, allowing devices to quickly identify available channels without being delayed by the presence of many devices, thus reducing individual channel access time

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses partial scanning action with NDP frames that only transmit necessary compressed SSID information rather than full frame structures, enabling devices to gain sufficient channel information faster without the overhead of complete scanning procedures

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2852221B1Method and apparatus for low-power scanning in WLAN system
Publication Date: 2019.03.06 LG ELECTRONICS INC
  • EP2852221B1 patent drawingFigure 1~2
  • EP2852221B1 patent drawingFigure 3
  • EP2852221B1 patent drawingFigure 4

AI summary

The present invention relates to a wireless communication system, and more specifically, disclosed are a method and an apparatus for low-power scanning in a WLAN system. A method for a station (STA) scanning in the wireless communication system, according to one embodiment of the present invention, comprises the steps of: transmitting a null data packet (NDP) probe request frame; and receiving from an access point (AP) a probe reply frame as a replay to the NDP probe request frame, wherein the NDP probe request frame can include a compressed service set ID (SSID).