Wireless Mesh Association Message Extension for Mobility Management

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Solution Overview

Problem

Current wireless mesh network protocols, such as IEEE 802.11s, have limited capabilities in managing mobility and updating associations between external nodes and mesh access points, particularly in supporting mobile stations switching between access points, and lack sufficient configuration options for mapping messages, leading to inefficiencies in communication and increased communication overhead.

Innovation Solution

The method extends the association message with features like a validity period for assignments, allowing either hard-state or soft-state management, and includes sequence numbers for better tracking of mapping information, enabling more flexible and efficient distribution of association data across the network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If standard association messages are used in IEEE 802.11s mesh networks, then basic routing functionality is maintained, but mobility management capability is insufficient and communication overhead increases

Engineering Contradiction:
Improvemobility management capabilityVSAvoidassociation message structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The association message is segmented into multiple fields including association information field, validity period field, and sequence number field. Each field serves a specific function: association information stores mapping relationships, validity period manages mobility by indicating when associations expire, and sequence numbers track updates. This segmentation allows the message to handle mobility while maintaining clear structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The association message introduces dynamic elements including validity periods that automatically expire and sequence numbers that increment with each update. These dynamic components enable the system to adapt to mobile stations switching between access points by automatically invalidating old associations and tracking new ones, transforming the static association message into a mobility-aware structure.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If validity periods are added to association messages, then mobility management is improved, but message size and processing complexity increase

Engineering Contradiction:
Improvemobility management flexibilityVSAvoidmessage data volume
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The validity period field is applied locally to specific association entries rather than globally to all associations. Each association can have its own validity period tailored to its specific requirements, allowing mobility management for individual mobile stations without unnecessarily increasing the size of messages for stationary associations. This localized application optimizes the balance between functionality and message size.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If sequence numbers are included in association messages, then mapping information tracking is improved, but communication overhead increases

Engineering Contradiction:
Improvemapping information tracking accuracyVSAvoidcommunication energy overhead
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The sequence number mechanism is self-service in that it automatically increments with each association message update without requiring external coordination or complex acknowledgment protocols. The receiving node can independently track updates by comparing sequence numbers, eliminating the need for additional confirmation messages and reducing overall communication overhead while maintaining precise tracking of mapping information changes.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2274935B1Method and device for creating at least one expansion of an association message for wireless mesh networks
Publication Date: 2014.08.27 UNIFY GMBH & CO KG
  • EP2274935B1 patent drawingFigure 1
  • EP2274935B1 patent drawingFigure 2
  • EP2274935B1 patent drawingFigure 3

AI summary

The invention relates to a method for operating a mesh network, especially according to IEEE standard 802.11s, wherein the mesh network comprises a plurality of network nodes, which have outer edge nodes and inner network nodes. A first edge node forms a connection point for external first stations disjunctive to the network, and a second edge node forms a connection point for external second stations disjunctive to the network, wherein data packets are to be exchanged between the first and second stations. During a switch of an external station from one edge node to another edge node, especially from a coverage area of the first edge node to a coverage area of the second network node, the respective association information of the network nodes is updated by means of an association message while inserting a validity duration for the association of the external stations connected to the edge nodes. The invention also relates to a device for carrying out the method for operating a mesh network.