WLAN Station Power Saving via Trigger Frame Resource Allocation
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Solution Overview
Problem
Current wireless local area network (WLAN) systems face challenges in efficiently managing power saving modes, particularly when a station receives a frame, leading to inaccurate network allocation vectors and inefficient power usage.
Innovation Solution
A method and apparatus for a station in a WLAN system to determine whether to transition to a doze state based on a trigger frame, using indicator information to allocate resources for uplink multi-user PPDU transmission, allowing the station to maintain a wake-up state when frames need to be received and operate in power saving mode during inaccessible channel durations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a station remains in wake-up state to receive frames, then frame reception reliability is improved, but power consumption increases
Solution Approach 1:
The station dynamically transitions between wake-up state and doze state based on whether it is allocated resources for uplink multi-user PPDU transmission. When resources are allocated, the station remains awake to receive and transmit frames reliably. When resources are not allocated, the station transitions to doze state to save power, thus adapting its operational state to current needs.
Solution Approach 2:
The station changes its operational parameter (power state) from wake-up to doze based on the resource allocation status indicated in the trigger frame. This parameter change allows the station to optimize between power consumption and frame reception reliability according to real-time network conditions.
2Use of energy by moving object
If a station transitions to doze state to save power, then power consumption is reduced, but network allocation vector accuracy deteriorates
Solution Approach 1:
The station determines whether to transition to doze state before actually entering that state, based on preliminary assessment of resource allocation in the trigger frame. This preliminary decision ensures that the station only enters doze state when it will not miss any allocated transmissions, thereby maintaining network allocation vector accuracy while enabling power savings.
Solution Approach 2:
The station uses feedback from the trigger frame (resource allocation information) to make informed decisions about state transitions. The indicator information in the trigger frame provides feedback that guides whether the station should remain awake or transition to doze, ensuring that network allocation vector accuracy is maintained when needed.
3Reliability
If a station remains awake during entire TXOP duration, then frame reception capability is improved, but power saving efficiency deteriorates
Solution Approach 1:
The transmission opportunity (TXOP) duration is segmented into periods when the station should remain awake and periods when it can transition to doze state. The station segments its operational states based on resource allocation status, remaining awake only during allocated transmission periods and transitioning to doze during unallocated periods, thus improving power saving efficiency without compromising frame reception capability.
Solution Approach 2:
The station employs periodic state transitions between wake-up and doze states during the TXOP duration, aligning with the periodic resource allocation pattern indicated by trigger frames. This periodic action allows the station to maintain frame reception capability during allocated periods while achieving power savings during unallocated periods.
Data Source
AI summary
A method for a station (STA) to operate in a power saving (PS) mode in a wireless LAN system that supports a high efficiency physical layer protocol data unit (HE PPDU), in one embodiment of the present invention, comprises the steps of: receiving a trigger frame which assigns a resource for transmission of an uplink multi-user (UL MU) PPDU; and determining whether to perform transition to a doze state on the basis of the trigger frame, wherein when the resource is not assigned to the STA through the trigger frame, the STA determines to perform transition to a doze state during a time period determined on the basis of an indicator information value of the trigger frame.