Multi-Band WLAN Scanning via AP Filtering
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Solution Overview
Problem
Current WLAN systems face challenges in accurately and efficiently performing multi-band scanning, leading to scanning delays and increased power consumption when devices need to switch between operating bands to discover access points.
Innovation Solution
A method and apparatus that enable a station (STA) or access point (AP) to transmit and receive frames containing information about supported operating classes and service set identifiers, allowing for the discovery of access points operating in different bands without switching channels, using probe request and response frames that include filtering indicators and target beacon transmission time offset information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a station switches channels to discover access points in different bands, then the station can find APs operating in other bands, but scanning delays and power consumption increase
Solution Approach 1:
The patent applies preliminary action by having the AP pre-process and filter multi-band scanning information before transmitting it to the STA. The AP receives probe requests, filters them based on supported operating classes and SSIDs, and prepares scan results in advance, allowing the STA to obtain band discovery information without performing time-consuming channel switches.
Solution Approach 2:
The patent uses the AP as an intermediary between the STA and the multi-band scanning process. Instead of the STA directly switching channels to discover APs, the STA sends probe requests to the current AP, which then acts as a mediator to provide filtered scanning information about APs in other bands, eliminating the need for direct channel switching by the STA.
2Measurement precision
If a station switches channels to discover access points in different bands, then the station can find APs operating in other bands, but power consumption increases
Solution Approach 1:
The AP performs preliminary filtering and preparation of scan results based on supported operating classes and SSID information before the STA needs the data. This pre-processing eliminates the need for the STA to perform energy-intensive channel switching operations, significantly reducing the STA's power consumption while maintaining accurate band discovery.
3Productivity
If the AP transmits filtered scan results with operating class and SSID information, then the STA can efficiently discover APs without channel switching, but the frame structure becomes more complex
Solution Approach 1:
The patent uses existing, standardized frame structures (probe request and probe response frames) that are already universally supported in WLAN systems. By incorporating operating class and SSID information into these existing frame types rather than creating new frame structures, the patent maintains compatibility with current WLAN infrastructure while enabling efficient multi-band scanning.
Data Source
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AI summary
The present invention relates to a wireless communication system and, more specifically, to a method and a device for scanning multiple bands in a wireless LAN system. The method by which a station (STA) scans in a wireless communication system, according to one embodiment of the present invention, comprises the steps of: transmitting a first frame to a first access point (AP); and receiving a second frame responding to the first frame from the first AP, wherein the first frame includes service set identifier (SSID) information and information on an operation class supported by the STA, and the second frame can include information for indicating whether or not to filter and information on a second AP.