WLAN Active Scanning with Selective Probe Response Timing

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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 inefficient scanning processes.

Innovation Solution

An active scanning method and apparatus that includes transmitting a probe request frame with specific information about target and non-target access points, preference criteria, and response reception times, allowing for selective and abortable scanning to reduce unnecessary probe responses and expedite the discovery of suitable access points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If active scanning is performed by transmitting probe request frames to all channels, then AP discovery capability is improved, but scanning time is prolonged and probe response frame flooding occurs

Engineering Contradiction:

ImproveAP discovery capabilityVSAvoidscanning time

Core Design Contradiction:

Difficulty of detecting and measuringVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the STA pre-select target APs based on stored information (such as previously scanned AP lists, frequency of access, or user preferences) before performing active scanning. This allows the STA to prioritize scanning on channels where target APs are likely to be found, reducing the need to scan all channels and thereby shortening scanning time while maintaining AP discovery capability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies local quality by making the scanning process selective rather than uniform. Instead of treating all channels equally, the STA concentrates scanning resources on specific channels where target APs are expected to be located, based on historical data or user-defined preferences. This localized approach improves scanning efficiency by focusing efforts where they are most needed.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If probe request frames are transmitted to all channels to ensure complete AP discovery, then detection completeness is improved, but the quantity of probe response frames increases causing flooding

Engineering Contradiction:

Improvedetection completenessVSAvoidquantity of probe response frames

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies preliminary action by pre-identifying target APs using stored information before initiating active scanning. This allows the STA to limit probe request transmissions only to channels where target APs are expected, thereby maintaining detection completeness for those specific APs while significantly reducing the total number of probe response frames received from non-target APs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies the taking out principle by extracting and removing non-essential scanning activities. Specifically, the STA excludes channels or APs that are not in the target list from active scanning, thereby eliminating unnecessary probe request transmissions and the corresponding probe response frames, thus reducing frame flooding while maintaining completeness for target APs.

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If sequential scanning of all channels is performed, then comprehensive network coverage is improved, but scanning speed is reduced

Engineering Contradiction:

Improvenetwork coverageVSAvoidscanning speed

Core Design Contradiction:

Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent applies preliminary action by pre-determining the scanning sequence and target channels based on stored AP information, user preferences, or historical access patterns. This allows the STA to skip channels where no target APs are expected, thereby maintaining comprehensive coverage of relevant networks while significantly improving scanning speed by avoiding unnecessary channel transitions.

Inventive Principle:

Principle #10Preliminary action

4Loss of information

If all APs respond to probe request frames, then AP visibility is improved, but network congestion and interference increase

Engineering Contradiction:

ImproveAP visibilityVSAvoidnetwork congestion and interference

Core Design Contradiction:

Loss of informationVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by having APs pre-prepare their visibility and response behavior based on stored information about expected probe requests. APs can pre-configure their response filters to only respond to probe requests for their specific SSID or BSSID, rather than responding to all probe requests. This maintains AP visibility for legitimate requests while reducing unnecessary responses that cause congestion and interference.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20260019930A1Method and apparatus of scanning in wireless local area network system

Publication Date: 2026.01.15 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 via a channel, and receiving by the station a probe response frame from a target access point (AP) to respond to the probe request frame. The probe request frame includes at least one of information regarding a response reception time and preference information regarding the target AP.