WLAN Power Management via Multicast Notification Frames

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Solution Overview

Problem

Current WLAN systems face challenges in reducing power consumption and latency, particularly in managing power save opportunities and adapting to scheduling changes for multicast groups in 802.11 wireless communication systems.

Innovation Solution

The solution involves providing timing information in communication frames to inform mobile devices of expected frame exchange periods, allowing them to transition to a Doze state and take advantage of power save opportunities, and incorporating Multicast Schedule Elements in beacon frames to manage power save opportunities for multicast traffic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mobile devices remain in Awake state to monitor all communication frames, then they can receive multicast traffic timely, but power consumption increases

Engineering Contradiction:
Improvetimely reception of multicast trafficVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The access point performs preliminary actions by sending notification frames before actual multicast data transmission. These notification frames contain advance information about upcoming multicast transmissions, allowing mobile devices to wake up in advance and prepare to receive data, thus balancing power savings with timely reception reliability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements dynamic power management where mobile devices can switch between Awake and Doze states based on reception needs. Devices wake up during notification frames and scheduled transmission periods, then return to Doze state during idle periods, creating a dynamic adaptation pattern that optimizes both power consumption and reception reliability

Inventive Principle:
Principle #15Dynamics

2Use of energy by moving object

If mobile devices enter Doze state to save power, then power consumption reduces, but latency increases when needing to receive data

Engineering Contradiction:
Improvepower consumptionVSAvoidlatency
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

Notification frames provide preliminary warnings about upcoming multicast transmissions, allowing devices to calculate optimal wake-up times. This advance notice enables devices to enter Doze state longer without excessive latency, as they wake up just in time for actual data reception rather than continuously monitoring

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system establishes periodic patterns where devices wake up at scheduled intervals to receive notifications and multicast data, then return to Doze state. This periodic wake-sleep cycle reduces average power consumption while maintaining acceptable latency by concentrating active periods around actual transmission events

Inventive Principle:
Principle #19Periodic action

3Adaptability or versatility

If mobile devices continuously monitor for scheduling changes, then they can adapt to multicast group changes, but power consumption increases

Engineering Contradiction:
Improveadaptation to scheduling changesVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The access point acts as an intermediary that consolidates scheduling change information and delivers it through efficient notification frames. Instead of devices continuously scanning for changes, the AP proactively pushes scheduling information to devices during scheduled notification periods, reducing the monitoring burden on power-constrained mobile devices while maintaining adaptability

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3624503B1WLAN system with opportunistic transitioning to a low power state for power management
Publication Date: 2021.12.08 APPLE INC
  • EP3624503B1 patent drawingFigure 1
  • EP3624503B1 patent drawingFigure 2
  • EP3624503B1 patent drawingFigure 3

AI summary

Embodiments described herein relate to providing reduced power consumption in wireless communication systems, such as 802.11 WLAN systems. Timing information regarding power save opportunities (PSOPs) may be provided in communication frames, which may inform mobile devices of expected frame exchange periods during which they may transition to a Doze state. Additional PSOP information may be included in beacon frames, which may inform mobile devices of expected multicast periods during which they may transition to a Doze state. This may operate to provide improvements in terms of power consumption.