Non-Contact RF Sleep Stage Detection from Respiration Variability

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Solution Overview

Problem

Existing respiratory disorder treatments face challenges with uncomfortable and poorly fitting patient interfaces, noisy vents, and cumbersome sleep stage determination methods that require electrical contact or multiple sensors, limiting their effectiveness and user experience.

Innovation Solution

A non-contact system using radio-frequency sensors to measure bodily movement and respiration signals for sleep stage determination, providing comfortable and efficient treatment adjustments based on sleep stages without direct electrical contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If non-contact radio-frequency sensors are used for sleep stage determination, then user comfort is improved by eliminating direct electrical contact, but measurement precision may be affected

Engineering Contradiction:
Improveuser comfortVSAvoidsleep stage determination accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces contact-based mechanical sensing systems with radio-frequency electromagnetic sensing. The system uses RF signals to detect bodily movements and respiration patterns without physical contact, thereby eliminating skin irritation and discomfort while maintaining measurement capability through signal processing algorithms that analyze movement patterns to determine sleep stages

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces radio-frequency electromagnetic waves as an intermediary between the sensor and the subject. Instead of direct electrical contact between sensors and skin, RF waves serve as the medium to detect physiological movements, allowing non-invasive measurement of sleep parameters while preserving measurement precision through appropriate signal reception and analysis

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple sensors and electrical contact are used for sleep stage determination, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvesleep stage determination accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the radio-frequency sensor system multi-functional by using it to detect multiple physiological parameters simultaneously - bodily movements, respiration rate, and sleep stage determination - all through a single sensing mechanism. This eliminates the need for separate specialized sensors for each measurement, thereby reducing device complexity while maintaining comprehensive sleep monitoring capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines multiple measurement functions into a single radio-frequency sensing system. Instead of using separate sensors for movement detection, respiration monitoring, and sleep stage classification, the system merges these functions into one integrated RF sensing approach, simplifying the overall device architecture while preserving measurement precision through combined signal analysis

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate sleep stage differentiation and comfortable treatment by eliminating the need for direct electrical contact, improving user comfort and treatment efficacy.

Implementation Method 1

A non-contact system using radio-frequency sensors to measure bodily movement and respiration signals for sleep stage determination

Methodology Applied
Scientific EffectRadio-frequency detection: Radar

Data Source

PatentEP3912553B1System and computer program for determining sleep stage
Publication Date: 2025.10.29 RESMED SENSOR TECH LTD
  • EP3912553B1 patent drawingFigure 1a
  • EP3912553B1 patent drawingFigure 1b
  • EP3912553B1 patent drawingFigure 1c

AI summary

Methods and apparatus monitor health by detection of sleep stage. For example, a sleep stage monitor (100) may access sensor data signals related to bodily movement and/or respiration movements. At least a portion of the detected signals may be analyzed to calculate respiration variability. The respiration variability may include one or more of variability of respiration rate and variability of respiration amplitude. A processor may then determine a sleep stage based on one or more of respiration variability and bodily movement, such as with a combination of both. The determination of sleep stages may distinguish between deep sleep and other stages of sleep, or may differentiate between deep sleep, light sleep and REM sleep. The bodily movement and respiration movement signals may be derived from one or more sensors, such as non-invasive sensor (e.g., a non-contact radio-frequency motion sensor or a pressure sensitive mattress).