WLAN Roaming via PSM Session Suspend
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Solution Overview
Problem
Current WLAN technologies face challenges in seamless roaming between access points, leading to potential loss of connection and service interruptions, especially in environments with outdated access points that do not support advanced roaming standards.
Innovation Solution
A communication device employs the 802.11 PSM power save mode to suspend sessions with both old and new access points, allowing for confirmation of a new connection before abandoning the existing one, using a pseudo power-save mode to hold data and ensure a smooth handoff without modifying existing access point hardware or software.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a communication device breaks connection with current access point to connect to a second access point, then roaming between access points is achieved, but connection loss and service interruption occur
Solution Approach 1:
The communication device performs preliminary actions by establishing connection with the second access point before breaking connection with the first access point. This ensures that a valid connection is ready before the old one is terminated, preventing connection loss and service interruption during roaming.
Solution Approach 2:
The device maintains continuous data transfer capability by overlapping the connection periods - keeping the first connection active until the second connection is confirmed working. This ensures uninterrupted service during the transition between access points.
2Reliability
If proposed roaming standards with out-of-band communication are implemented, then seamless roaming is achieved, but compatibility with existing access points is lost
Solution Approach 1:
The communication device performs self-service by managing its own roaming process independently. It autonomously establishes connections with new access points and manages connection transitions without requiring special support or intelligence from the access points, thus maintaining compatibility with existing infrastructure.
Solution Approach 2:
Instead of requiring access points to implement complex roaming standards and out-of-band communication capabilities, the invention inverts the approach by having the communication device handle all roaming logic and connection management, making the access points simple and compatible.
3Reliability
If connection with current access point is maintained while establishing new connection, then connection reliability is improved, but device complexity increases
Solution Approach 1:
The communication device uses universal connection management procedures that work across different access points and scenarios. The same connection establishment and management protocols are used whether maintaining old connection or switching to new one, simplifying the overall complexity despite the reliability requirements.
Data Source
AI summary
A communication device using a current wireless network via a first access point confirms availability of a second access point before breaking the current connection. To confirm availability of the second access point, the communication device sends a power management message that causes the first access point to store packets during the power management period. After the connection to the second access point is confirmed, the second session may be put on hold using the same technique while the connection to the first access point is restored, the stored packets processed and the connection closed. Then the connection to the second access point may be reactivated and further communication made through the second access point.