WLAN Access Point Role Segmentation for Handover Trigger Optimization

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently managing handover triggers between WiFi and cellular networks, particularly in conserving mobile device battery life and ensuring timely handover during voice calls, as existing systems often require excessive frame transmission and receiver activation, leading to rapid battery discharge.

Innovation Solution

The system configures WLAN access points into specific measurement and reporting roles (Portal AP, Border AP, Interior AP, and Monitor AP) to minimize unnecessary link measurements and data transmission, allowing for targeted handover decision-making and reducing the processing load on the infrastructure, while using Monitor APs to scan multiple channels and track call states for battery conservation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the MN transmits many extra frames or keeps its receiver on for extended periods to enable handover triggers, then handover accuracy is improved, but battery life deteriorates

Engineering Contradiction:
Improvehandover trigger accuracyVSAvoidbattery life
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent segments the APs into different roles (Portal APs, Border APs, Interior APs) with distinct measurement and reporting responsibilities. Portal APs perform comprehensive measurements near building exits, while Border and Interior APs perform limited or no measurements. This segmentation reduces the overall measurement burden on the MN and network infrastructure, thereby conserving battery life while maintaining handover accuracy at critical locations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by making measurement requirements location-dependent. APs are configured with different measurement intensities based on their proximity to building exits and their role in the handover process. This ensures that measurements are performed only where necessary (near exits) rather than continuously throughout the entire service area, reducing energy consumption while maintaining trigger accuracy where needed.

Inventive Principle:
Principle #3Local quality

2Reliability

If all APs perform comprehensive link measurements continuously, then handover trigger reliability is improved, but network infrastructure processing load increases

Engineering Contradiction:
Improvehandover trigger reliabilityVSAvoidinfrastructure processing load
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the AP population into functional segments with differentiated measurement responsibilities. Portal APs (located near exits) perform comprehensive measurements for reliable handover triggers, while Border and Interior APs perform minimal or no measurements. This segmentation maintains trigger reliability at critical locations while significantly reducing the aggregate processing load on the infrastructure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by having only the necessary subset of APs (Portal APs) perform comprehensive measurements, rather than requiring all APs to do so. This partial measurement approach is sufficient for maintaining handover reliability since measurements are concentrated where they matter most (near building exits), avoiding unnecessary processing elsewhere in the network.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2345284B1Configuring access point measurement and reporting functionality depending upon it's role in inter-rat handover
Publication Date: 2018.06.13 CISCO TECHNOLOGY INC
  • EP2345284B1 patent drawingFigure 1
  • EP2345284B1 patent drawingFigure 2
  • EP2345284B1 patent drawingFigure 3

AI summary

A system and method are provided in which access point (AP) devices in a wireless local area network (WLAN) are typed or configured into one of three measurement and reporting roles: Monitor-Mode AP (MMAP), Portal AP (PAP), a Border AP (BAP) or an Interior AP (IAP). APs are assigned specific link measurement requirements according to their assigned type or role. In general, MMAPs and PAPs have the greatest measurement and reporting responsibilities, BAPs have less measurement and reporting responsibilities than PAPs and IAPs have the least measurement and reporting responsibilities. The APs generate measurements that are supplied to appropriate equipment to facilitate handover decisions with respect to a dual- mode wireless client device that roams between the WLAN and another network or vice versa. As a result, link measurements are only performed by APs in locations where such measurements are necessary for handover service, thus reducing the overall processing load on the WLAN infrastructure.