MLD Roaming Handover Between AP MLDs Without WLAN Disconnection

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Solution Overview

Problem

Existing wireless LAN systems face challenges in seamless roaming between access points (APs) without disconnection, leading to packet loss and delay, particularly in next-generation standards like IEEE 802.11be (EHT) with increased spatial streams.

Innovation Solution

A method for MLD roaming between APs involves exchanging request and response frames to enable seamless movement between APs without additional authentication or association procedures, using identifiers to facilitate roaming within a roaming-enabled group, ensuring continuous connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional authentication and association procedures are performed during roaming, then network security and connection establishment are ensured, but connection disconnection and packet loss occur

Engineering Contradiction:
Improveconnection continuityVSAvoidroaming delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-establishing roaming agreements between STAs and target APs before actual roaming occurs. TheSTA transmits a roaming request frame containing target AP information to the current AP, which forwards it to the target AP for agreement establishment. This preliminary agreement setup enables seamless roaming without requiring full authentication procedures during the actual transition, thus maintaining connection continuity while reducing roaming delay.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses the current AP as an intermediary to facilitate seamless roaming. The current AP receives the roaming request frame from the STA, validates it, and forwards it to the target AP. This intermediary mechanism allows the STA to establish a new connection to a target AP while maintaining the existing connection to the current AP, preventing connection disconnection and packet loss during the roaming process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If additional authentication procedures are performed during roaming, then network security is enhanced, but packet loss and delay increase

Engineering Contradiction:
Improvenetwork securityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by performing authentication and agreement establishment before the actual roaming occurs. The STA and target AP exchange authentication information and establish a roaming agreement in advance through the current AP. This preliminary authentication ensures network security while avoiding the need for repeated authentication procedures during roaming, thus reducing energy consumption.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The current AP serves as an intermediary that handles authentication and roaming agreement management. It validates roaming requests, forwards authentication information to target APs, and manages the roaming process. This intermediary approach ensures network security is maintained during roaming without requiring the STA to perform additional authentication procedures, thereby reducing energy consumption.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If full association procedures are re-executed during roaming, then connection establishment is ensured, but productivity decreases

Engineering Contradiction:
Improveconnection establishmentVSAvoiddata transmission efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by establishing roaming agreements and validating authentication information before the STA actually roams to the target AP. The current AP and target AP pre-configured roaming parameters and validated authentication credentials in advance. This preliminary setup ensures that when roaming occurs, the connection establishment is rapid and reliable, without requiring full association procedures to be re-executed, thus maintaining high data transmission efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The current AP acts as an intermediary that manages the roaming transition and ensures smooth connection establishment. It validates the roaming request, forwards necessary information to the target AP, and coordinates the handover process. This intermediary mechanism ensures that connection establishment is reliable while minimizing the time and resources required, thereby maintaining high productivity during data transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4708965A1Method and device for performing MLD roaming without disconnection between aps in wireless LAN system
Publication Date: 2026.03.11 LG ELECTRONICS INC
  • EP4708965A1 patent drawingFigure 1(a)~1(b)
  • EP4708965A1 patent drawingFigure 2
  • EP4708965A1 patent drawingFigure 3

AI summary

A method and a device for performing MLD roaming without disconnection between APs in a wireless LAN system are presented. Specifically, a first non-AP STA transmits an MLD roaming request frame to a first AP, and receives an MLD roaming response frame from the first AP. The first non-AP STA roams from the first AP to a third AP on the basis of the MLD roaming response frame. The first AP, which operates in a first link, and a second AP, which operates in a second link, belong to a first AP MLD. The first non-AP STA, which operates in the first link, and a second non-AP STA, which operates in the second link, belong to a first non-AP MLD. The third AP belongs to a second AP MLD.