WLAN Station Power Saving Mode NAV Management
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Solution Overview
Problem
Wireless Local Area Network (WLAN) systems face challenges in efficiently managing power saving modes, particularly when a station (STA) needs to maintain a wake-up state without transitioning to a power saving mode to accurately manage Network Allocation Vectors (NAV) and conserve power during channel access restrictions.
Innovation Solution
A method and apparatus for operating in a power saving mode in a WLAN system that involves receiving frames with duration information, setting NAV based on this information, and determining whether to transition to a power saving mode, including using HE PPDU frames to indicate whether duration information has changed, and managing doze states based on resource allocation in trigger frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a station (STA) maintains a wake-up state to accurately manage Network Allocation Vectors (NAV), then NAV management accuracy is improved, but power consumption increases
Solution Approach 1:
The patent applies dynamics by making the STA's operational state changeable between wake-up and doze modes based on NAV status. The STA dynamically transitions to a doze state when NAV is zero (no channel access restrictions) and remains in wake-up state when NAV is non-zero (channel access restrictions present), optimizing power consumption while maintaining NAV management accuracy when needed
Solution Approach 2:
The patent changes the operational parameter (power state) of the STA based on the NAV parameter. By monitoring NAV values and adjusting the power state accordingly, the system achieves efficient power management - transitioning to low-power doze state when channel access is unrestricted (NAV=0) and maintaining wake-up state when channel access is restricted (NAV>0)
2Use of energy by moving object
If a station (STA) transitions to power saving mode during channel access restrictions, then power consumption is reduced, but NAV management accuracy deteriorates
Solution Approach 1:
The patent uses dynamic state transitions based on real-time NAV conditions. The STA remains in wake-up state during channel access restrictions (when NAV > 0) to ensure accurate NAV management, and only transitions to doze state when NAV = 0, thus avoiding NAV management accuracy deterioration while achieving power savings
3Measurement precision
If a station (STA) remains in wake-up state continuously, then NAV management accuracy is maintained, but power conservation efficiency deteriorates
Solution Approach 1:
The patent implements periodic state transitions rather than continuous wake-up operation. The STA periodically transitions to doze state when NAV = 0 and wakes up when NAV becomes non-zero, achieving power conservation efficiency while maintaining NAV management accuracy when channel access restrictions are present
Solution Approach 2:
The patent changes the power state parameter based on NAV parameter values. By setting power state to doze when NAV = 0 and wake-up when NAV > 0, the system achieves efficient power conservation without compromising NAV management accuracy during periods when channel access restrictions exist
Data Source
AI summary
According to an embodiment of the present invention, a method in which a station (STA) operates in a power saving (PS) mode in a wireless LAN system supporting a high efficiency physical layer protocol data unit (HE PPDU) comprises the steps of: receiving a trigger frame for allocating a resource for uplink multi-user (UL MU) PPDU transmission; and determining whether the STA shifts into a doze state, on the basis of the trigger frame, wherein the STA determines to shift into the doze state when the resource is not allocated to the STA through the trigger frame, and a time interval in which the STA operates in the doze sate may be determined on the basis of a PS mode field included in the trigger frame.