Direct Roaming Through Target AP MLD for Seamless Wi-Fi Handover
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Solution Overview
Problem
Existing Wi-Fi networks face issues with seamless roaming due to coverage gaps leading to sudden signal drops, resulting in disruptions and the need for break-before-make transitions, which can cause connectivity loss.
Innovation Solution
A method and system enabling stations to roam directly to a target access point within a seamless mobility domain without reassociation, utilizing proactive pre-roaming preparation and context transfer between access points to maintain connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If break-before-make roaming is used to handle coverage gaps, then the station can quickly roam to a different AP MLD to maintain connectivity, but there will be likely be some disruptions due to break-before-make roaming
Solution Approach 1:
The patent applies preliminary action by having the target AP MLD prepare for the roaming event in advance. The target AP receives a roaming indication from the serving AP MLD before the actual roaming occurs, allowing it to pre-establish the necessary connection state and receive buffer data, thereby eliminating the need for break-before-make transitions and reducing disruption during the roaming event.
2Reliability
If the station performs seamless roaming through its old serving access point multi-link device, then connectivity can be maintained, but the station cannot perform seamless roaming through coverage gaps leading to sudden signal drops
Solution Approach 1:
The patent introduces an intermediary mechanism where the target AP MLD acts as a mediator to receive buffered data from the serving AP MLD before the station actually roams. This intermediary data transfer mechanism allows the station to maintain seamless connectivity even when moving through coverage gaps, as the target AP is already prepared with the necessary data to continue the communication without interruption.
3Reliability
If the target access point receives context from the serving access point during roaming, then the roaming response can be based on complete context information, but additional time is required for context transfer
Solution Approach 1:
The patent applies preliminary action by having the target AP receive the station's context information from the serving AP in advance of the actual roaming event. The target AP buffers this context information and uses it when the station initiates roaming, allowing for rapid and accurate roaming decisions without requiring additional time during the critical roaming transition moment.
Data Source
AI summary
A station (STA) (e.g., a non-AP MLD) in a SMD is described that roams through a target AP (e.g., an AP MLD) in the same SMD as the current AP serving the STA. That is, typically roaming in a SMD is done through the serving AP. However, there are situations when the STA may lose its connection to the serving AP suddenly such as if the STA moves behind a wall or wakes up from a sleep mode in a different location. In those cases, the STA may not be able to transmit the roaming request to its serving AP. The embodiments herein provide techniques for the STA to initiate a roam to a target AP without having to associate with the target AP (assuming the target AP is in the same SMD as the serving AP).