Wireless Station Sleep State Scheduling and Data Buffering

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Solution Overview

Problem

Wireless devices in IEEE 802.11 compliant WLANs experience significant power consumption due to inefficient algorithms for controlling the sleep state, leading to suboptimal power savings despite entering a low power mode.

Innovation Solution

Implementing a processing system that schedules sleep state intervals, enters a sleep state at the beginning of the scheduled interval, and buffers data for transmission following the sleep state, using software modules to progressively adjust sleep durations based on traffic likelihood and transmission parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If STAs enter sleep state to save power, then power consumption is reduced, but risk of missing incoming data increases

Engineering Contradiction:

Improvepower consumptionVSAvoiddata reception reliability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The AP pre-queues downlink data for STAs before they enter sleep state. The TIM in beacon frames indicates which STAs have queued data, allowing STAs to wake up only when necessary. This preliminary data queving action resolves the contradiction by ensuring data availability while enabling extended sleep periods.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The AP provides feedback to STAs through beacon frames containing TIM information about queued downlink data. STAs use this feedback to determine whether to wake up from sleep state or remain sleeping, optimizing the balance between power savings and data reception reliability.

Inventive Principle:

Principle #23Feedback

2Reliability

If STAs wake up frequently to check for data, then data reception reliability is improved, but power consumption increases

Engineering Contradiction:

Improvedata reception reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The AP performs preliminary data queving and notifies STAs in advance through beacon frames. This allows STAs to extend their sleep intervals without missing data, reducing wake-up frequency while maintaining reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

STAs wake up periodically at beacon intervals to check for data, rather than continuously monitoring. The periodic wake-up pattern, combined with TIM information about queued data, optimizes the balance between power consumption and data reception.

Inventive Principle:

Principle #19Periodic action

3Reliability

If STAs remain in active state to ensure data reception, then data reception reliability is improved, but power savings are reduced

Engineering Contradiction:

Improvedata reception reliabilityVSAvoidpower savings

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The AP queues downlink data in advance and notifies STAs before they enter sleep state. This preliminary action ensures that STAs can confidently enter low-power mode knowing their data is safely queued, achieving both reliability and power savings.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The AP acts as an intermediary by buffering downlink data and managing the TIM information. This intermediary role allows STAs to sleep without directly monitoring the channel, reducing their power consumption while maintaining reliable data delivery through the AP's data management.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9167530B2Power saving modes in wireless devices

Publication Date: 2015.10.20 QUALCOMM INC

AI summary

Various aspects of apparatus for accessing a network through a wireless access point and methods of power savings for such apparatus include scheduling a sleep state interval, entering a sleep state at the beginning of the scheduled sleep interval, and buffering data during the sleep state for transmission following the sleep state.