AP Probe Response Channel Width Adaptation for WLAN Scanning
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Solution Overview
Problem
In IEEE 802.11 WLAN systems, especially in M2M communication scenarios with a large number of devices, there is a need for an improved scanning method that minimizes power consumption, as conventional scanning methods are inefficient in terms of power usage and scanning time, particularly due to interference from neighboring channels.
Innovation Solution
The proposed method involves an access point (AP) supporting both 1 MHz and 2 MHz channel widths, receiving probe request frames in either width, and transmitting probe response frames in the same width, with the option to include location information about 1 MHz channels within the frame control field of the probe response frame, allowing the station (STA) to adjust its channel scanning accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the STA scans all channels including neighboring channels to ensure complete network discovery, then the scanning coverage is improved, but the power consumption and scanning time increase due to interference from neighboring channels
Solution Approach 1:
The patent extracts and removes the interfering neighboring channels from the scanning process. The AP identifies channels that are not part of the BSS (Basic Service Set) and excludes them from the probe response, allowing the STA to skip scanning these channels while still achieving complete network discovery.
Solution Approach 2:
The probe response frame acts as an intermediary that carries channel information from the AP to the STA. This intermediary provides the STA with knowledge about which channels to scan and which to exclude, eliminating the need for the STA to independently determine this information through exhaustive scanning.
2Reliability
If the STA scans all channels including neighboring channels to ensure complete network discovery, then the scanning coverage is improved, but the scanning time increases due to interference from neighboring channels
Solution Approach 1:
The patent extracts and removes the interfering neighboring channels from the scanning process. The AP identifies channels that are not part of the BSS (Basic Service Set) and excludes them from the probe response, allowing the STA to skip scanning these channels while still achieving complete network discovery.
Solution Approach 2:
The probe response frame acts as an intermediary that carries channel information from the AP to the STA. This intermediary provides the STA with knowledge about which channels to scan and which to exclude, eliminating the need for the STA to independently determine this information through exhaustive scanning.
3Productivity
If the probe response frame is transmitted in a wider channel width to improve communication efficiency, then the data rate is improved, but the compatibility with narrow channel width STAs deteriorates
Solution Approach 1:
The patent applies local quality by making the probe response frame structure adaptive to the specific STA's capabilities. The AP transmits channel information in a localized manner within the frame, allowing each STA to extract only the relevant information for its supported channel width without requiring changes to the overall transmission protocol.
Solution Approach 2:
The patent changes the parameter representation in the probe response frame based on the STA's capabilities. The channel information is encoded in a flexible format that can be interpreted by both narrow and wide channel width STAs, allowing the same frame to serve multiple device types without sacrificing communication efficiency.
Data Source
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AI summary
The present invention relates to a wireless communication system and, more particularly, to an improved scanning method and apparatus in a wireless LAN system. A method by which an access point (AP) supports the scanning of a station (STA) in a wireless LAN system, according to one embodiment of the present invention, includes the steps of: receiving, by the AP which supports first and second channel widths, a probe request frame in the first channel width or second channel width from the STA; and transmitting a probe response frame, which responds to the probe request frame, to the STA. When the probe request frame is received in the first channel width, the probe response frame can be transmitted in said first channel width. When the probe request frame is received in the second channel width, the probe response frame can be transmitted in said second channel width.