Active Scanning Method for Wireless LAN Access Point Discovery
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Solution Overview
Problem
In wireless LAN systems, stations face challenges in efficiently identifying access points across multiple channels, leading to prolonged scanning times as access points typically respond only through their primary channel, not secondary channels, forcing stations to sequentially scan each channel to find a desired access point.
Innovation Solution
An active scanning method where a station transmits probe request frames through multiple channels, including both primary and secondary channels, and receives probe response frames containing primary channel information, allowing for immediate access to the access point on the identified primary channel, thereby reducing scanning time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a station sequentially scans multiple channels to find an access point, then the station can identify the access point location, but the scanning time becomes excessively long
Solution Approach 1:
The access point transmits its primary channel information in advance within beacon frames and probe response frames. When a station receives these frames, it obtains the primary channel information beforehand, eliminating the need to sequentially scan multiple channels to discover the access point's location, thus dramatically reducing scanning time while maintaining accurate location identification
2Reliability
If an access point responds to probe requests only on its primary channel, then the access point follows standard protocol, but stations must scan multiple channels increasing time consumption
Solution Approach 1:
The patent introduces probe response frames as an intermediary mechanism that carries primary channel information from the access point to the station. This intermediary frame allows the access point to maintain protocol compliance by responding only on its primary channel, while simultaneously providing stations with the information needed to avoid scanning multiple channels, thus resolving the time consumption issue without compromising protocol reliability
Data Source
AI summary
Disclosed is an active scanning method in a wireless LAN system. The active scanning method comprises: a step of transmitting a probe request frame via a predetermined channel; and a step of receiving, from an access point, a probe response frame corresponding to the probe request frame via a predetermined channel. The probe response frame includes main channel information on the access point. Thus, the access point can be quickly scanned.