Cross-Link Wi-Fi Power Saving with APSD and Broadcast TWT
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Solution Overview
Problem
Current Wi-Fi designs lack efficient power save mechanisms for Access Point (AP) devices, limiting the effectiveness of Power Save (PS) operations, especially in multi-link scenarios, and there is a need for cross-link power management signaling to support both AP and non-AP stations.
Innovation Solution
Implement cross-link signaling with Automatic Power Save Delivery (APSD) on the AP side, including unscheduled (U)-APSD and scheduled (S)-APSD, and introduce explicit Target Wake Time (TWT) for broadcast TWT to enhance power saving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If cross-link signaling with APSD and explicit TWT is implemented on the AP side, then power saving efficiency is improved, but device complexity increases
Solution Approach 1:
The patent segments power management into separate mechanisms: APSD for automatic power save delivery and TWT for scheduled wake times. Each mechanism operates independently on different links, allowing granular power control without requiring complete system redesign, thus managing complexity while improving power efficiency.
Solution Approach 2:
The patent implements dynamic TWT scheduling where the AP can flexibly suspend and resume TWTs for member STAs based on traffic conditions. This dynamic adjustment allows the system to adapt power consumption to actual needs, improving power saving efficiency without requiring static rigid configurations that would increase complexity.
2Loss of energy
If cross-link signaling is implemented to support AP power management, then power management effectiveness is improved, but ease of operation deteriorates
Solution Approach 1:
The patent implements self-service power management where the AP autonomously manages its own power state through APSD and TWT mechanisms. The AP can automatically enter doze mode and wake up at scheduled times without manual intervention, improving power management effectiveness while maintaining operational simplicity through automation.
Solution Approach 2:
The patent incorporates feedback mechanisms where the AP monitors traffic conditions and link status to dynamically adjust power management decisions. This feedback loop allows the system to automatically optimize power consumption based on actual network conditions, improving effectiveness without requiring complex manual configuration.
3Loss of energy
If TWTs are suspended and resumed for all member STAs, then power saving efficiency is improved, but loss of time increases
Solution Approach 1:
The patent implements preliminary TWT scheduling where wake times are pre-negotiated and scheduled in advance. Member STAs know exactly when to wake up and when the AP will be available, eliminating unnecessary waiting time and allowing efficient power saving during doze periods without losing time on ad-hoc wake-up negotiations.
Solution Approach 2:
The patent uses periodic TWT intervals where the AP and STAs establish regular wake-up schedules. This periodic structure allows devices to enter doze mode confidently knowing when to expect communication, improving power efficiency while minimizing time loss through predictable, rhythm-based operation rather than irregular wake-ups.
Data Source
AI summary
Cross link signaling in a WiFi protocol which supports cross link power management, having Automatic Power Save Delivery (APSD) on the AP side, and which includes unscheduled (U)-APSD and scheduled (S)-APSD, over one or multiple links or sub-channels. An explicit TWT for a broadcast TWT provides the flexibility of having a broadcast TWT SP between two subsequent negotiated broadcast TWT SPs. Individual/broadcast TWTs can be suspended and resumed for all member STAs toward improving efficiency of AP power saving. Additional elements and benefits are described.