Access Point Discovery Using Dynamic Scan Dwell Time
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Solution Overview
Problem
In dense wireless local area networks (WLANs), non-AP stations (STAs) face challenges in discovering available access points (APs) due to factors like overlapping basic service sets (BSSs) causing interference and congestion, leading to inefficient network connectivity, delayed responses, and degraded performance.
Innovation Solution
Implementing a system where STAs include a scan dwell time (SDT) and priority in probe requests, and APs prioritize responses based on SDT and priority, while also providing metrics like average response time and channel congestion to optimize scanning and probing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If scan dwell time is reduced to improve network responsiveness, then network latency is reduced, but access point discovery reliability deteriorates
Solution Approach 1:
The patent implements dynamic scan dwell time adjustment where the dwell time is not fixed but varies based on channel conditions, signal strength, and network environment. The system automatically extends dwell time when needed (e.g., weak signals, high interference) and reduces it when conditions are favorable, resolving the contradiction between speed and reliability.
Solution Approach 2:
The patent changes the scan dwell time parameter dynamically based on multiple factors including received signal strength indicator (RSSI), channel utilization, and probe response timing. By adjusting this critical parameter in response to real-time conditions, the system optimizes both discovery reliability and responsiveness.
2Reliability
If probe request priority is increased to improve response timing, then probe response reliability is improved, but channel congestion increases
Solution Approach 1:
The patent applies different priority levels (high, normal, low) to different types of probe requests based on their source and purpose. Mobile devices performing roaming get high priority, while periodic scans get normal or low priority. This localized differentiation ensures reliable responses where needed without uniformly increasing channel congestion.
Solution Approach 2:
The system uses feedback mechanisms where access points monitor channel conditions and adjust their response behavior accordingly. When congestion is detected, APs may delay or prioritize responses based on the feedback information about channel utilization and queue status, balancing reliability with congestion management.
3Adaptability or versatility
If multiple WLAN networks operate on shared channels to increase network coverage, then network availability is improved, but interference and congestion increase
Solution Approach 1:
The patent implements preliminary channel assessment and selection before establishing connections. Devices perform advance probing and evaluate channel conditions to identify less congested channels or optimal APs, reducing interference before it affects connectivity. This preliminary action allows multiple networks to coexist more peacefully.
Solution Approach 2:
The patent introduces intermediary mechanisms like reduced neighbor reports and channel utilization metrics that mediate between multiple APs and devices. These intermediary data structures enable devices to make informed decisions about channel selection and AP association, reducing direct interference between overlapping networks.
Data Source
AI summary
The disclosure describes systems and methods for improving access point discovery with dynamic dwell time. A station can transmit a probe request to be received by an access point. The probe request can identify a scan dwell time of the station. While waiting for the probe response during the scan dwell time, the station can determine that the probe response from the access point has yet to be received at a point during the scan dwell time. Responsive to the determination, the station can dynamically increase the scan dwell time while waiting for the probe response from the access point. The access point can receive the probe request and determine whether to respond within the scan dwell time. The access point can identify a relevant metric of time and generate the probe response. The access point can transmit the probe response to the station within the scan dwell time.