Restricted TWT Scheduling for Low-Latency WLAN Power Saving

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Solution Overview

Problem

Existing wireless communication systems in artificial reality environments face challenges in maintaining low latency and power efficiency, particularly in head wearable displays, due to the need for rapid image rendering and sensor data processing, which can lead to judder and motion sickness if latency exceeds 11 ms.

Innovation Solution

Implementing restricted target wake time (rTWT) operations in wireless local area networks (WLANs) to manage wake times and reduce power consumption by using defined service periods, ensuring efficient communication and reduced latency for latency-sensitive traffic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If continuous wireless communication is maintained to reduce latency, then response time is improved, but power consumption increases

Engineering Contradiction:

ImprovelatencyVSAvoidpower consumption

Core Design Contradiction:

Loss of timeVSUse of energy by moving object

Solution Approach 1:

The patent implements Target Wake Time (TWT) mechanism where devices wake up at predetermined periodic intervals to exchange data packets. This periodic communication pattern ensures that latency-sensitive traffic receives timely delivery while allowing devices to remain in low-power sleep mode between wake periods, thus resolving the contradiction between maintaining low latency and reducing power consumption

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The access point schedules and announces TWT wake times in advance to devices before they actually wake up. This preliminary scheduling allows devices to plan their wake cycles optimally, ensuring that they are awake only when necessary for data transmission, thereby minimizing both latency for scheduled traffic and overall power consumption

Inventive Principle:

Principle #10Preliminary action

2Reliability

If wake times are extended to ensure data transmission completion, then reliability is improved, but latency increases

Engineering Contradiction:

Improvedata transmission completionVSAvoidlatency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements dynamic TWT mechanisms where wake time durations and intervals are adjusted based on real-time network conditions, device priorities, and traffic requirements. High-priority latency-sensitive traffic receives shorter, more frequent wake periods, while less time-critical traffic uses extended wake periods, thus dynamically balancing reliability of completion against latency

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent segments wireless communication into distinct TWT service periods with different characteristics. Some service periods are designated for latency-sensitive traffic with guaranteed delivery within specific time windows, while other periods handle less time-critical traffic. This segmentation allows the system to ensure reliable completion for critical data without unnecessarily extending wake times for all traffic types

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12581407B2Systems and methods of restricted TWT for wireless communication

Publication Date: 2026.03.17 META PLATFORMS TECHNOLOGIES LLC

AI summary

A device may include one or more processors. The one or more processors may be configured to determine a capabilities code indicating at least one of a plurality of defined capabilities of the device relating to restricted target wake time (rTWT) operations in a wireless local area network (WLAN). The one or more processors may be configured to wirelessly transmit, via a transmitter, a first frame including the capabilities code.