Persistent TWT Session Recovery via AP Reboot Data Offload
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Solution Overview
Problem
The IEEE 802.11ax standard's Target Wake Time (TWT) mechanism is vulnerable to disruptions during Access Point (AP) reboots, leading to loss of session information and potential packet drops due to unsynchronized beacon intervals after a reboot, which affects power save efficiency and network performance.
Innovation Solution
Implementing persistent TWT sessions by sending session information to a secondary device before a downtime event, such as an AP reboot, and retrieving this information to reestablish sessions and synchronize beacon timings, ensuring seamless connectivity and power save operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If TWT mechanism is implemented for power save operations, then battery life of client devices is extended, but session information is lost during AP reboots causing packet drops
Solution Approach 1:
The patent applies preliminary action by saving TWT session information to a storage medium before an AP reboot occurs. The system proactively stores target wake time, service period, and station identifier data in advance, ensuring that when the AP reboots, the session can be restored without interruption or packet loss, thus maintaining both power save efficiency and session reliability.
2Reliability
If TWT sessions are maintained across AP reboots, then session continuity is preserved, but additional complexity is introduced for saving and retrieving session information
Solution Approach 1:
The patent applies copying by creating a duplicate copy of the TWT session information and storing it in a storage medium. This copy contains all essential session parameters (target wake time, service period, station identifier) that can be quickly retrieved after a reboot, preserving session continuity without requiring complex restoration logic or additional negotiation overhead.
3Productivity
If beacon intervals are desynchronized after AP reboot, then AP can restart services, but TWT sessions become disrupted causing increased management traffic
Solution Approach 1:
The patent applies feedback by using the saved TWT session information to guide the beacon interval synchronization process after AP reboot. The system retrieves the stored session parameters and uses them to adjust and synchronize beacon intervals with the previously established TWT schedule, ensuring that wake times and service periods remain aligned without requiring extensive management traffic for renegotiation.
Data Source
AI summary
Systems, methods, and computer readable mediums for persistent TWT sessions include establishing, by an access point, a plurality of sessions with a plurality of stations, wherein one or more of the plurality of sessions comprise a target wake time (TWT), determining, by the access point, that a downtime event will occur before a TWT of a particular station of the plurality of stations, in response to the downtime event occurring during the TWT of the particular station, sending, by the access point, information associated with the plurality of sessions to a secondary device, after the downtime event, retrieving, by the access point, the information associated with the plurality of sessions from the secondary device, and reestablishing, by the access point using the information, the plurality of sessions.