TWT Schedule Adjustment for Wireless Power Savings

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Solution Overview

Problem

Electronic devices communicating via wireless local area networks (WLANs) face challenges with power consumption and latency due to the main radio remaining in a higher-power mode unnecessarily, especially when the device is unavailable during targeted wake-up time (TWT) service periods (SPs).

Innovation Solution

An interface circuit in an electronic device determines and modifies the TWT SP schedule for a recipient device based on its availability information, adjusting the TWT SP start time, duration, or excluding SPs when the device is unavailable, to ensure the wake-up radio transitions to a higher-power mode only when necessary, thereby reducing power consumption and latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the main radio remains in higher-power mode to ensure availability during TWT service periods, then reliability of communication is improved, but power consumption increases

Engineering Contradiction:

Improveavailability during TWT service periodsVSAvoidpower consumption of main radio

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the TWT service period schedule adjustable and adaptable. The access point modifies TWT SP parameters (start time, duration, interval) based on recipient device availability information, transforming a static schedule into a dynamic one that responds to changing conditions. This allows the main radio to remain in higher-power mode only when necessary, resolving the contradiction between reliability and power consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes parameters of the TWT service period schedule (start time, duration, interval between SPs) based on recipient device availability. By modifying these parameters dynamically, the system ensures communication reliability during available periods while minimizing power consumption during unavailable periods, directly addressing the technical contradiction.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If the TWT service period schedule is fixed, then device complexity is reduced, but adaptability to device availability changes deteriorates

Engineering Contradiction:

ImproveTWT service period schedule managementVSAvoidadaptability to availability information

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements feedback by having the access point receive availability information from recipient devices and use this feedback to modify the TWT service period schedule. The access point adjusts schedule parameters based on the feedback about when devices are available or unavailable, creating a closed-loop system that balances simplicity with adaptability.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies preliminary action by having recipient devices provide availability information in advance (through TWT setup requests or other communications). This allows the access point to pre-adjust the TWT service period schedule to match anticipated availability patterns, reducing the need for complex real-time adjustments while maintaining adaptability.

Inventive Principle:

Principle #10Preliminary action

3Use of energy by moving object

If the main radio is turned off to save power, then power consumption is reduced, but latency increases when waking up for TWT service periods

Engineering Contradiction:

Improvepower consumption of main radioVSAvoidwake-up latency

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the access point send wake-up packets through the low-power wake-up radio before the main radio needs to be fully active. This allows the main radio to be awakened in advance of actual data transmission needs, reducing wake-up latency while still maintaining low power consumption during idle periods.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses the low-power wake-up radio as an intermediary between the access point and the main radio. The wake-up radio handles preliminary wake-up signaling, allowing the main radio to transition from low-power mode efficiently without significant latency, thus resolving the contradiction between power savings and wake-up time.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10904829B2Device-availability-based wake-up time schedule

Publication Date: 2021.01.26 APPLE INC

AI summary

An interface circuit in an electronic device (such as an access point) may provide a targeted wake-up time (TWT) service period (SP) schedule to a recipient electronic device. During operation the interface circuit may receive a TWT setup request associated with the recipient electronic device, where the TWT setup request includes non-availability information specifying one or more times when the recipient electronic device will be unavailable. For example, the non-availability information may include one or more times when the recipient electronic device has limited ability to transmit and/or receive. The interface circuit may provide a TWT setup response for the recipient electronic device, where the TWT setup response includes information specifying the TWT SP schedule for the recipient electronic device that includes at least one of: a TWT SP start time, a TWT SP duration, or an interval between TWT SPs.