WLAN Access Point Weighted List for Seamless Roaming

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Solution Overview

Problem

Existing WLAN networks face challenges in maintaining continuous connectivity for mobile terminals as they move out of range of access points, leading to momentary losses in Wide Area Network (WAN) connectivity due to the lack of efficient failover mechanisms between community WLAN networks managed by the same operator.

Innovation Solution

A method is introduced where access points perform quality and load measurements to trigger either an assisted or autonomous selection procedure, providing a weighted list of candidate access points for failover to minimize connectivity loss, while ensuring the mobile terminal manages its connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the mobile terminal autonomously manages its own connectivity switching between access points, then the device complexity and control flexibility are improved, but the switching time increases causing momentary loss of WAN connectivity

Engineering Contradiction:
Improveconnectivity management flexibilityVSAvoidswitching time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent introduces a server as an intermediary that assists the mobile terminal in selecting target access points during roaming. The server receives information from the terminal about current and candidate access points, then provides recommended target access points based on network conditions, thereby reducing the terminal's decision-making burden and accelerating the switching process while maintaining terminal autonomy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements preliminary scanning and evaluation of candidate access points before actual switching is needed. The terminal proactively identifies and evaluates potential target access points in advance, and the server pre-computes optimal switching targets based on current network conditions, so that when switching becomes necessary, the process can be executed rapidly with minimal connectivity interruption.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the mobile terminal performs comprehensive scans to find the best access point, then the reliability of connectivity is improved, but the switching time increases causing momentary loss of WAN connectivity

Engineering Contradiction:
Improveconnectivity reliabilityVSAvoidscan time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The server acts as an intermediary that performs or coordinates comprehensive network assessments without requiring the terminal to conduct exhaustive scans. The server aggregates information from multiple access points and network sources to determine optimal target access points, thereby ensuring reliable connectivity selection while minimizing the time the terminal needs to spend on scanning and evaluation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary identification and pre-evaluation of candidate access points before switching is triggered. The terminal pre-scans for available access points and the server pre-assesses their suitability, so that when actual switching becomes necessary, the selection process is already substantially complete, reducing both scan time and connectivity interruption.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the access point provides a weighted list of candidate access points with instantaneous load measurements, then the productivity of the failover process is improved, but the device complexity increases due to server coordination requirements

Engineering Contradiction:
Improvefailover speedVSAvoidsystem architecture complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The server serves as an intermediary that consolidates the complexity of coordinating multiple access points and gathering instantaneous load measurements. Rather than requiring complex peer-to-peer communication between access points and terminals, the server centralizes the information gathering and processing functions, simplifying the overall system architecture while enabling rapid failover through pre-computed weighted candidate lists.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent merges the functions of multiple access points and the server into a coordinated failover system. The server combines instantaneous load measurements from multiple access points, terminal capability information, and network conditions into a single weighted candidate list, thereby improving failover productivity through centralized intelligence while managing complexity through functional consolidation.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If the access point uses long-term statistics for autonomous selection, then the ease of operation is improved by reducing server dependency, but the reliability decreases due to outdated load information

Engineering Contradiction:
Improveautonomous operation capabilityVSAvoidaccess point selection accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The access point performs preliminary analysis and maintains updated long-term statistics about network conditions and access point performance. By pre-processing historical data and maintaining current baseline information, the access point can make autonomous selections with reasonable accuracy even without instantaneous server measurements, balancing operational simplicity with selection reliability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3689029B1Method of aiding toggling of a mobile terminal between community wireless local area networks
Publication Date: 2021.09.15 SAGEMCOM BROADBAND SAS
  • EP3689029B1 patent drawingFigure 1~2
  • EP3689029B1 patent drawingFigure 3~4
  • EP3689029B1 patent drawingFigure 5

AI summary

To aid the toggling of a mobile terminal from a first community wireless local area network to a second community wireless local area network respectively managed by first and second access points, the first access point performs measurements (602) of quality of communication with the said mobile terminal and/or of operational loading; by comparing (605, 609) the measurements with thresholds, the first access point can trigger (606) a selection procedure assisted by a server or trigger (610) an autonomous selection procedure, on completion of which the first access point transmits (611) to the mobile terminal a weighted list of access points that are candidates for toggling. In the assisted selection procedure, the first access point constructs the weighted list by taking into account instantaneous measurements, provided by the server, of operational loading of the candidate access points, and, in the autonomous selection procedure, the first access point constructs the weighted list by taking into account long-term statistics of operational loading of the candidate access points.