Compressed PPG Sampling for Low-Power Packet-Loss-Tolerant BANs

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Solution Overview

Problem

Current signal processing methods in body area networks (BANs) face challenges in reducing power consumption and computational complexity while maintaining application-specific quality metrics, particularly in healthcare applications, where packet loss rates are high and bandwidth overhead is significant.

Innovation Solution

The implementation of non-uniform sampling techniques using compressed sensing (CS) to acquire and reconstruct signals, allowing for reduced power consumption and lower bandwidth overhead by generating non-uniform sampling instances and sensing samples of signals, which can be transmitted and reconstructed efficiently, even in the presence of packet losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional Nyquist sampling is used to acquire signals in BANs, then signal fidelity is maintained, but power consumption and bandwidth overhead increase significantly

Engineering Contradiction:
Improvesignal fidelityVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the sampling rate parameter from Nyquist rate to lower rates, and transforms the signal representation parameters through compression sensing algorithms, enabling faithful signal recovery at lower sampling rates by exploiting signal sparsity in transformed domains

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional mechanical sampling approaches with compression sensing mathematical transformations, using linear algebra operations and optimization algorithms to reconstruct signals from fewer samples, substituting direct physical sampling with computational reconstruction

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

2Loss of information

If traditional sampling methods are used, then complete signal information is captured, but computational complexity at sensors increases

Engineering Contradiction:
Improvesignal information completenessVSAvoidcomputational complexity at sensors
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent segments the computational workload between the sensor (acquiring fewer samples) and the receiver/reconstructor (performing complex reconstruction algorithms), dividing the overall signal processing task into acquisition and reconstruction phases with different complexity requirements

Inventive Principle:
Principle #1Segmentation

3Reliability

If Forward Error Correction coding is used to handle packet loss, then communication reliability improves, but bandwidth overhead and sensor complexity increase

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidbandwidth overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent converts the harmful effect of packet loss into a beneficial feature by designing compression sensing acquisition to be inherently robust to packet loss, where the random sampling pattern and sparsity-based reconstruction naturally tolerate missing data without requiring additional error correction overhead

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP3672084A1Method and apparatus for under-sampled acquisition and transmission of photoplethysmograph (PPG) data and reconstruction of full band PPG data at the receiver
Publication Date: 2020.06.24 QUALCOMM INC
  • EP3672084A1 patent drawingFigure 1
  • EP3672084A1 patent drawingFigure 2
  • EP3672084A1 patent drawingFigure 3

AI summary

Certain aspects of the present disclosure relate to a method for compressed sensing (CS). The CS is a signal processing concept wherein significantly fewer sensor measurements than that suggested by Shannon/Nyquist sampling theorem can be used to recover signals with arbitrarily fine resolution. In this disclosure, the CS framework is applied for sensor signal processing in order to support low power robust sensors and reliable communication in Body Area Networks (BANs) for healthcare and fitness applications.