WLAN RF Channel Scanning for Mobile Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mobile communication devices experience increased battery power consumption when operating in unknown regulatory domains due to the inefficiency of passive scan mode in wireless local area networks (WLANs), as they must continuously monitor RF channels for regulatory information without knowing which channels are reserved for non-WLAN operations.
Innovation Solution
A method where a mobile device scans RF channels using a combination of passive and active scan modes, changing the scan status from passive to active upon decoding valid information frames, allowing for more efficient channel usage and reduced power consumption by transitioning to active scanning once regulatory domain information is received.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If passive scan mode is used in unknown regulatory domain, then regulatory domain information can be obtained, but battery power consumption increases significantly
Solution Approach 1:
The patent applies preliminary action by performing passive scanning only on a limited set of candidate channels (e.g., channels 1, 6, and 11 in 2.4 GHz band) before regulatory domain information is obtained. This preliminary passive scan allows the device to detect valid WLAN information frames and determine which channels are actually in use, thereby identifying the regulatory domain without continuously scanning all possible channels. Once the regulatory domain is identified, the device can switch to active scan mode which consumes less power.
Solution Approach 2:
The patent implements dynamics by dynamically switching between passive scan mode and active scan mode based on the regulatory domain status. The scanning strategy is not static but adapts to the current state: when regulatory domain information is unknown, passive scan is used on candidate channels; when information is obtained, active scan is used on confirmed channels. This dynamic adaptation optimizes power consumption while ensuring regulatory compliance.
2Loss of information
If passive scan mode is continuously used, then regulatory domain information can be obtained, but scanning efficiency decreases
Solution Approach 1:
The patent performs preliminary passive scanning on a restricted set of candidate channels to quickly identify the regulatory domain. This preliminary action is sufficient to determine which channels are valid for WLAN operation in the current region. After this initial identification, continuous passive scanning on all channels is avoided, and instead active scanning is performed only on the identified valid channels, significantly improving scanning efficiency.
Solution Approach 2:
The patent applies local quality by focusing scanning efforts on specific local characteristics of the regulatory domain. Rather than uniformly scanning all channels with the same method, the device identifies the local regulatory characteristics through preliminary passive scan and then applies the appropriate scanning strategy (active scan) only to the locally relevant channels. This localized approach improves efficiency by avoiding unnecessary scanning of channels that are not in use in the current region.
3Productivity
If active scan mode is used in unknown regulatory domain, then scanning efficiency improves, but risk of operating on reserved channels increases
Solution Approach 1:
The patent performs preliminary passive scanning on candidate channels before switching to active scanning. This preliminary action identifies which channels are actually used for WLAN operations in the current regulatory domain. By establishing this knowledge base first, the device can then safely use active scan mode on the identified channels without risking operation on reserved or prohibited channels, thus maintaining both efficiency and compliance.
Solution Approach 2:
The patent uses feedback from the preliminary passive scan results to guide subsequent active scanning operations. The passive scan provides feedback about which channels contain valid WLAN information frames, indicating they are permissible for use. This feedback mechanism ensures that active scanning is only performed on channels that have been verified as compliant with local regulations, thereby maintaining reliability while improving efficiency.
Data Source
AI summary
Techniques are described for use in scanning by a mobile device which is configured to communicate in compliance with regulatory requirements of a regulatory domain based on country information communicated in one or more beacon frames. The mobile device scans a radio frequency (RF) band using passive scan operations on RF channels having passive scan status, where each passive scan operation involves monitoring an RF channel in attempt to decode a beacon frame. When the mobile device successfully decodes, on an RF channel for a passive scan operation, an information frame of a type that is different from a beacon frame, it changes the passive scan status of the RF channel to an active scan status and performs an active scan operation on the RF channel.