WLAN Power Save Mode Wakeup Signaling
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Solution Overview
Problem
In wireless local area networks (WLANs), stations (STAs) operating in power save mode face challenges in managing power consumption and efficiently exchanging frames, as they transition between awake and doze states, leading to potential unnecessary power consumption and inefficiencies, especially in machine-to-machine (M2M) communications where power management is critical.
Innovation Solution
A method and apparatus that allow an access point (AP) to control the power save mode operation of STAs, enabling efficient transitions between awake and doze states by using signaling during awake periods, considering application layer turnaround time (ALTT) to prevent unnecessary power consumption, and optimizing power management during single transmission opportunity (TXOP) intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the STA operates in power save mode by transitioning to doze state, then power consumption is reduced, but frame reception efficiency deteriorates due to wake-sleep transitions
Solution Approach 1:
The AP transmits a wake-up signal to the STA before the STA needs to wake up for its next awake period. This preliminary action allows the STA to remain in doze state longer and wake up only when necessary to receive frames, reducing the number of unnecessary wake-sleep transitions while ensuring frame reception efficiency is maintained.
2Productivity
If the STA remains in awake state to ensure frame reception, then frame reception efficiency is improved, but power consumption increases
Solution Approach 1:
The STA feeds back information to the AP about its awake periods and frame reception status. The AP uses this feedback to optimize the wake-up signaling strategy, adjusting when to send wake-up signals based on actual STA behavior and traffic patterns, thereby reducing unnecessary power consumption while maintaining frame reception efficiency.
3Reliability
If the AP sends wake-up signals frequently to ensure STA is awake, then frame delivery reliability is improved, but power save performance deteriorates
Solution Approach 1:
The AP sends wake-up signals selectively rather than continuously - only when there is actual traffic to deliver or when the STA is approaching its scheduled awake period. This partial action approach ensures frame delivery reliability is maintained for actual traffic while avoiding excessive wake-up signals that would degrade power save performance.
Data Source
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AI summary
A communication method based on a power save mode, performed by a station (STA) in a wireless local area network (WLAN) system is provided. The method includes switching to an awake state; transmitting a wakeup poll frame to an access point (AP) the wakeup poll frame indicating that the station has switched to the awake state; receiving a wakeup confirm frame from the AP in response to the wakeup poll frame, the wakeup poll frame including an awake duration field, the awake duration field indicating an awake duration as a duration in which the station maintains the awake state; and switching to a doze state after the time interval indicated by the awake duration field has lapsed.