WLAN Probe Response Filtering for Faster Network Scanning

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Solution Overview

Problem

Existing wireless local area network (WLAN) scanning methods, particularly active scanning, suffer from prolonged scanning times and excessive flooding of probe response frames due to indiscriminate AP responses and lack of targeted channel scanning.

Innovation Solution

Implement a method where stations transmit probe request frames with inclusion and exclusion lists, along with capability and preference information, allowing access points to selectively respond based on station requirements, and utilize scanning abort and selective channel scanning to reduce unnecessary probe responses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If active scanning is used to discover accessible wireless networks, then scanning speed is improved, but probe response frame flooding occurs and scanning time is lengthened

Engineering Contradiction:

Improvescanning speedVSAvoidprobe response frame flooding

Core Design Contradiction:

SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent segments the probe response process by introducing two types of responses: immediate probe responses for APs matching inclusion criteria, and delayed probe responses for APs requiring further evaluation. This segmentation prevents flooding by controlling which APs respond immediately while others wait for additional filtering

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by having the station transmit capability information and preference information before receiving probe responses. The APs use this preliminary information to determine whether to respond immediately or delay their response, preventing unnecessary flooding before it occurs

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If APs respond to all probe request frames, then network coverage is improved, but scanning time is lengthened due to sequential channel scanning

Engineering Contradiction:

Improvenetwork coverageVSAvoidscanning time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent introduces dynamic response timing where APs can choose to respond immediately or delay their response based on their characteristics and the station's preferences. This dynamic approach allows the system to adapt to different scanning scenarios, maintaining coverage while reducing overall scanning time through parallel processing of multiple channels

Inventive Principle:

Principle #15Dynamics

3Use of energy by moving object

If stations wait for beacon frames in passive scanning, then energy consumption is reduced, but time to discover AP is increased

Engineering Contradiction:

Improveenergy consumptionVSAvoidtime to discover AP

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the station transmit probe request frames with inclusion and exclusion lists before waiting for responses. This allows the station to proactively initiate the scanning process rather than passively waiting for beacons, significantly reducing the time to discover APs while maintaining reasonable energy consumption through targeted scanning

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12452775B2Method and apparatus of scanning in wireless local area network system

Publication Date: 2025.10.21 ELECTRONICS & TELECOMM RES INST

AI summary

A scanning method in a wireless local area network (WLAN) system is provided. The scanning method includes transmitting, by a station, a probe request frame and receiving, by the station, a probe response frame from an access point (AP). The AP determines whether to transmit the probe response frame in response to the probe request frame using information indicated by the probe request frame.