Sensor Data Synchronization via Sequence Count in Patient Monitors

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Solution Overview

Problem

Existing patient monitor systems face challenges in synchronizing data collection and communication across different sensor modules due to clock drift and lack of guaranteed delivery times, leading to desynchronized data display.

Innovation Solution

The system uses a start message with a current time and incrementing sequence count to synchronize data transmission from sensor modules, with a USB controller providing an 11-bit sequence count for aligned data display across all modules, ensuring consistent timing for waveform and numeric parameter data updates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional communication systems without guaranteed delivery times are used, then system complexity is reduced, but data synchronization between sensor modules deteriorates

Engineering Contradiction:

Improvedata synchronizationVSAvoidcommunication system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The host device sends a start message to sensor modules in advance, providing a reference time and start value before data transmission begins. This preliminary synchronization action ensures that all modules are aligned before collecting and transmitting patient data, resolving the synchronization issue without requiring complex ongoing communication protocols.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Sensor modules use the sequence count values received from the host as feedback to adjust their local timing and determine when to transmit data packets. This feedback mechanism ensures that even if modules are frequently connected and disconnected, they resynchronize using the latest start value provided by the host.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If sensor modules are frequently connected and disconnected for patient transport, then patient mobility is improved, but data synchronization accuracy deteriorates

Engineering Contradiction:

Improvepatient mobilityVSAvoiddata timing accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

When a sensor module connects to the system, the host immediately provides an updated start value and current sequence count as a preliminary synchronization action. This allows the module to quickly align with the system timing without requiring complex handshaking protocols, enabling frequent connections and disconnections while maintaining synchronization accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses an incrementing sequence count that wraps around (e.g., 11-bit counter from 0 to 2047) as a parameter change mechanism. This allows the synchronization reference to continuously update without requiring absolute time alignment, making the system robust to frequent module connections and disconnections while maintaining timing accuracy.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If clock drift between network nodes is present, then system simplicity is maintained, but waveform alignment between sensor modules deteriorates

Engineering Contradiction:

Improvesynchronization system complexityVSAvoidwaveform alignment

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The host device acts as an intermediary that provides a central reference time and sequence count to all sensor modules. Instead of requiring modules to synchronize with each other directly (which would be complex and vulnerable to clock drift), the host mediates the synchronization by broadcasting the current time and start value to all modules, ensuring consistent waveform alignment without complex inter-module communication.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9149188B2Systems and methods for synchronizing data received from multiple sensor modules in a patient monitor system

Publication Date: 2015.10.06 SHENZHEN MINDRAY BIO MEDICAL ELECTRONICS CO LTD

AI summary

A patient monitor system synchronizes patient data acquired by a plurality of sensor modules. Patient data from the sensor modules are synchronized by transmitting, from a patient monitor host, a start message that each newly connected sensor module uses to determine when to begin transmitting patient data to the patient monitor host. At a predetermined count interval, the patient monitor host also broadcasts an incrementing sequence count value to each of the connected sensor modules. The sensor modules use the sequence count values and the start message to determine when the patient monitor host expects each sensor module to transmit data packets. Each data packet sent by the sensor modules includes a sequence count value that the patient monitor host uses to align the various waveforms for display.