Adaptive Access Point Scan Method for Wireless LAN
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Solution Overview
Problem
Current access point scan methods in wireless LAN systems do not effectively select an access point and radio channel that provide optimal communication quality, with passive scanning being inefficient due to longer scanning times and active scanning consuming more power without ensuring the best combination.
Innovation Solution
An active scanning method that sets an order for scanning radio channels, generates a list of connection candidate access points based on received signal strength, selects the best access point, and adjusts scanning parameters like packet error rate and busy ratio to efficiently connect to an access point and radio channel with good communication quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If passive scanning is used to reduce power consumption, then power consumption is reduced, but scanning time becomes longer
Solution Approach 1:
The patent applies dynamics by making the scanning method adaptive rather than static. The station dynamically switches between passive and active scanning based on real-time conditions such as whether connection candidates are found and signal strength thresholds. This dynamic adjustment optimizes both power consumption and scanning time by using the most efficient method for each specific situation.
Solution Approach 2:
The patent changes the parameter of scanning behavior from fixed to variable. By introducing conditions (signal strength thresholds, candidate availability) that trigger switches between passive and active scanning, the system adjusts its operational parameters dynamically. This allows the station to maintain low power consumption during normal operation while quickly transitioning to active scanning when needed to find or verify connection candidates.
2Loss of time
If active scanning is used to shorten scanning time, then scanning time is reduced, but power consumption increases
Solution Approach 1:
The patent applies partial action by using active scanning selectively rather than continuously. The station performs active scanning only when necessary (when no connection candidates are found via passive scanning or when signal strength verification is needed), and uses passive scanning for routine monitoring. This partial use of the more energy-intensive active scanning method reduces overall power consumption while maintaining the ability to shorten scanning time when needed.
3Reliability
If scanning is performed on all available radio channels to ensure optimal communication quality, then communication quality is improved, but scanning time increases
Solution Approach 1:
The patent applies preliminary action by performing passive scanning first to identify connection candidates and their signal strengths before committing to active scanning. This preliminary assessment allows the station to pre-filter which channels and access points warrant further investigation, avoiding the need to perform time-consuming active scanning on all channels. Connection candidates found during passive scanning are prioritized, and active scanning is focused only on verifying or finding additional candidates among these prioritized targets.
Solution Approach 2:
The patent segments the scanning process into distinct phases: passive scanning for initial discovery and candidate identification, followed by selective active scanning for verification or additional candidate finding. This segmentation divides the overall scanning task into manageable stages, allowing the system to gather connection configuration information efficiently in the first phase and then focus resources on verifying the most promising candidates in the second phase, rather than uniformly scanning all channels with the same method.
4Loss of time
If connection is established as soon as a connectable access point is found to reduce scanning time, then scanning time is reduced, but communication quality may not be optimal
Solution Approach 1:
The patent applies feedback by using signal strength information gathered during passive scanning to guide the connection decision. Rather than connecting to the first access point found, the station evaluates signal strength metrics and uses this feedback to prioritize connection candidates. The system continuously monitors signal strength and uses this information to determine whether to proceed with connection or to continue scanning for potentially better candidates, ensuring that connection decisions are based on quality metrics rather than mere sequence.
Data Source
AI summary
A probe request for an access point scan is transmitted over a specified radio channel according to an order of scanning, a connection candidate AP list including information indicating an access point which transmits a probe response and a received signal strength indication is generated when the probe response is received, the connection candidate AP list is referred to, one access point is selected from access points whose corresponding received signal strength indications exceed a predetermined threshold, connection processing is performed on the one access point being selected on the specified radio channel, and scanning is repeatedly performed by specifying a radio channel which is second in the order until scanning on all radio channels for which the order of scanning is set is completed when no probe response is received or the connection candidate AP list includes no received signal strength indication which exceeds the threshold.