Chained Wake-Up Scheduling for Low-Power STA Groups
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Solution Overview
Problem
The increase in the number of wake-up packets that need to be decoded by a wake-up receiver decreases the battery standby time of a station (STA) as the number of wake-up receivers increases, as the STA does not know if a wake-up packet is addressed to itself until decoding the MAC portion, leading to unnecessary decoding.
Innovation Solution
A station determines a common service period for a group of STAs with a head node for communication, and based on energy harvesting information, defers wake-up packets using a deferral time, transmitting or backscattering a wake-up command to another STA to deliver the packet after the deferral time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of wake-up receivers increases, then more STAs can be served, but the number of unnecessary wake-up packet decodes increases, decreasing battery standby time
Solution Approach 1:
The patent segments the wake-up packet processing by introducing a head node that performs initial decoding and filtering. The head node decodes the MAC portion of wake-up packets and determines whether they are addressed to specific STAs in the group, preventing other STAs from performing unnecessary decoding operations. This segmentation reduces the energy consumption of individual STAs while maintaining the ability to serve multiple STAs.
Solution Approach 2:
The head node acts as an intermediary between the access point and the group of STAs. It receives wake-up packets from the access point, decodes them, and selectively forwards only relevant packets to specific STAs. This intermediary function eliminates the need for each STA to independently decode all incoming wake-up packets, thereby conserving battery energy while supporting multiple STAs in the group.
2Reliability
If all STAs wake up simultaneously to check for wake-up packets, then no packet is missed, but energy consumption increases and battery standby time decreases
Solution Approach 1:
The system performs preliminary action by having the head node decode and filter wake-up packets before they reach the individual STAs. The head node prepares the wake-up information in advance, determining which STAs should wake up and forwarding only their relevant packets. This preliminary processing ensures reliable packet delivery while allowing STAs to remain in low-power mode longer, thus extending battery standby time.
Solution Approach 2:
The patent introduces dynamic wake-up timing where different STAs wake up at different times based on their individual schedules and the head node's forwarding decisions. Instead of simultaneous wake-up, STAs can wake up opportunistically when their specific wake-up packets are forwarded by the head node. This dynamic approach maintains reliability for each STA while reducing overall energy consumption across the group.
3Measurement precision
If STAs decode the MAC portion of every wake-up packet to determine if addressed to themselves, then accurate identification is achieved, but unnecessary decoding increases with more STAs, reducing battery efficiency
Solution Approach 1:
The decoding task is segmented and centralized at the head node. The head node performs the energy-consuming MAC portion decoding of wake-up packets, while individual STAs only need to process the simplified forwarding indications from the head node. This segmentation maintains accurate address identification (since the head node performs the full decoding) while dramatically reducing the energy consumption at each STA.
Solution Approach 2:
The head node serves as an intermediary that handles the complex MAC decoding task. It decodes the wake-up packets, identifies the intended recipients, and forwards only the relevant packets to the appropriate STAs. This intermediary approach ensures accurate address identification is achieved by the head node, while individual STAs avoid the energy cost of decoding, thus reducing overall energy loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method reduces unnecessary decoding of wake-up packets, conserving battery life by optimizing the wake-up process for a group of STAs through deferred and chained wake-up commands.
Implementation Method 1
a station (STA) decodes the identity of the wake-up receiver encoded within the MAC portion of the wake-up packet
Implementation Method 2
the STA may transmit or backscatter, to a second STA of the group of STAs, a wake-up command that includes the wake-up packet addressed to the first STA
Data Source
AI summary
Methods and apparatuses are described herein for chained and delayed wake-up. For example, a station (STA) may determine, at the formation of a group of STAs, a common service period for the group. The STA may determine a deferral time for a first STA of the group. The deferral time may indicate when the first STA wakes up to receive a wake-up packet. The STA may receive, from an access point (AP), during a service period in which the STA acts as a head node for communication with the AP, a wake-up packet addressed to the first STA. The STA may transmit, based on a determination that the deferral time associated with the wake-up packet addressed to the first STA ends after the service period in which the STA acts as a head node, a wake-up command that includes the wake-up packet addressed to the first STA.