Low-Power Wake-Up Radio Pulse Multiplexing for Wi-Fi Power Reduction

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Solution Overview

Problem

Existing wireless local area networks (WLANs) face challenges in maintaining always-on connectivity while minimizing battery life expenditure, particularly in applications like social networking and IoT devices, due to the high power consumption of constantly providing power to WLAN radios.

Innovation Solution

The implementation of a low-power wake-up radio (LP-WUR) technology that uses a 1× symbol duration pulse for wake-up packets, compatible with 11ax OFDMA, reducing transmission time and out-of-band emission to minimize interference with OFDMA signals and conserve power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If WLAN radio is constantly powered to maintain always-on connectivity, then connectivity availability is improved, but power consumption increases

Engineering Contradiction:

Improveconnectivity availabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system divides the wireless communication function into two separate radio systems: a low-power wake-up radio (LP-WUR) that remains always-on for detecting wake-up packets, and a main WLAN radio that sleeps and only activates when needed. This segmentation allows the device to maintain connectivity availability through the LP-WUR while dramatically reducing power consumption by keeping the main WLAN radio off most of the time.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of continuous operation, the main WLAN radio operates periodically - sleeping during intervals and activating only when the LP-WUR detects a wake-up packet. This periodic action pattern eliminates unnecessary continuous power consumption while maintaining the ability to respond to connectivity requirements when they arise.

Inventive Principle:

Principle #19Periodic action

2Reliability

If traditional wake-up packets are used, then wake-up functionality is achieved, but transmission time and out-of-band emission increase causing interference with OFDMA signals

Engineering Contradiction:

Improvewake-up functionalityVSAvoidinterference with OFDMA signals

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the wake-up packet parameters by using a 1× symbol duration pulse instead of traditional longer-duration wake-up packets. This parameter change reduces both the transmission time and the out-of-band emission levels, thereby minimizing interference with concurrent OFDMA signals while preserving the wake-up functionality. The pulse-based approach with optimized duration creates a sharper, more contained signal that causes less spectral leakage.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9980228B2Low-power wake-up packet generation

Publication Date: 2018.05.22 INTEL CORP

AI summary

Embodiments of low-power wake-up packet generation are generally described herein. A wireless device modulates an LP-WUR (low-power wake-up radio) bit sequence with an LP-WUR pulse to obtain a plurality of modulated LP-WUR signals, each modulated LP-WUR signal having a 1× symbol duration. The wireless device multiplexes, in a time domain, an OFDMA (orthogonal frequency division multiple access) signal with a 4× symbol duration with four modulated LP-WUR signals, to generate a multiplexed signal. The wireless device encodes for transmission of the multiplexed signal to a peer device to wake up a WLAN (wireless local area network) radio of the peer device and to another device with an OFDMA signal.