Wake-Up Receiver Power Save Protocol for IoT Latency

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Solution Overview

Problem

Current wireless communication systems face challenges in achieving ultra-low power consumption and low latency simultaneously during power save mode, particularly in IoT applications, due to the delay associated with waking up the main radio using a wake-up receiver, which can lead to increased latency and reduced channel usage efficiency.

Innovation Solution

Implementing a wake-up receiver that operates independently of the main radio, using simple modulation schemes like OOK with repetition, and leveraging AP power save protocols to prevent unintended transitions to a doze state, allowing the wake-up receiver to recognize wake-up signals without activating the main radio, thus reducing power consumption and latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the main radio is periodically woken up 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 wireless device is divided into two independent radio units: a main radio for data transmission/reception and a wake-up receiver for monitoring wake-up signals. This segmentation allows each component to operate independently, enabling the main radio to remain in doze state while the wake-up receiver stays active, thus reducing overall power consumption while maintaining data reception reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The wake-up receiver acts as an intermediary between the external wake-up signals and the main radio. It monitors for wake-up signals and triggers the main radio to wake up only when necessary, eliminating the need for periodic main radio activations and reducing power consumption while ensuring data is not missed.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of time

If the wake-up receiver continuously monitors for wake-up signals, then data availability detection is improved, but power consumption increases

Engineering Contradiction:

Improvedata availability detection timeVSAvoidpower consumption

Core Design Contradiction:

Loss of timeVSUse of energy by moving object

Solution Approach 1:

The wake-up receiver operates periodically rather than continuously, activating at specific intervals to monitor for wake-up signals. This periodic operation reduces power consumption compared to continuous monitoring while still providing timely detection of data availability, balancing energy efficiency with responsiveness.

Inventive Principle:

Principle #19Periodic action

3Use of energy by moving object

If the main radio stays in doze state to save power, then power consumption is reduced, but latency increases due to wake-up delay

Engineering Contradiction:

Improvepower consumptionVSAvoidlatency

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The wake-up receiver performs preliminary monitoring for wake-up signals before the main radio needs to be activated. When a wake-up signal is detected, the wake-up receiver triggers the main radio to wake up immediately, eliminating the need for periodic wake-up checks and reducing latency while keeping the main radio in doze state for extended periods to save power.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20240323848A1Power save protocol for low power device exploiting wakeup signal receiver

Publication Date: 2024.09.26 NEWRATEK

AI summary

Disclosed herein is a method performed by a wireless device. The method includes wirelessly transmitting a legacy physical layer protocol data unit (PPDU) before wirelessly transmitting a wake-up receiver PPDU to protect the wake-up receiver PPDU. The legacy PPDU includes a preamble and a legacy frame. The legacy frame includes a power management field that indicates that the wireless device is transitioning to a doze state to cause other wireless devices to refrain from transmitting to the wireless device.