PS-Poll Group-Addressed Polling for Low-Power Wi-Fi

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Solution Overview

Problem

Battery-powered sensor devices that need to wake up occasionally to communicate data face significant battery life reduction due to frequent wake-ups for multicast and broadcast frames under current wireless standards, which require waking up every 200-400 msec to check for transmissions.

Innovation Solution

Implementing group-addressed polling techniques that allow network controllers and subscriber stations to buffer and retransmit multicast and broadcast frames, enabling devices to wake up less frequently and request buffered packets only when necessary, thereby reducing unnecessary power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wireless devices wake up at every DTIM interval to receive broadcast and multicast frames, then all broadcast and multicast frames are received, but battery life is severely reduced

Engineering Contradiction:

Improveframe reception reliabilityVSAvoidbattery life

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The network controller buffers broadcast and multicast frames before the wireless device wakes up, preparing the data in advance so that the device can receive multiple frames in a single wake-up event rather than needing to wake up for each frame transmission

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Multiple broadcast and multicast frames that would traditionally be transmitted separately at different DTIM intervals are merged into a single buffered transmission, allowing the wireless device to receive all frames during one wake-up period

Inventive Principle:

Principle #5Merging (Combining)

2Productivity

If wireless devices wake up frequently to check for buffered unicast frames, then data communication is maintained, but power consumption increases

Engineering Contradiction:

Improvedata communication efficiencyVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The polling mechanism is extended to handle both unicast and group-addressed frames through a single PS-POLL transaction, making the polling process multi-functional and eliminating the need for separate wake-up events for different frame types

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The network controller prepares and buffers both unicast and group-addressed frames in advance, so that a single PS-POLL from the wireless device can retrieve all pending frames regardless of type, reducing the frequency of wake-up events

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9544850B2Enhancing ps-poll for low-power wifi

Publication Date: 2017.01.10 TAHOE RES LTD

AI summary

After waking from a sleep mode, a wireless communication device may poll a network controller for any broadcast and/or multicast messages. The device and the network controller may agree to this arrangement ahead of time, so that the network controller will know to buffer such messages until the device requests them. A format for enabling this capability is described.