基於低功率藍芽之無線多導極⼼電圖系統於多閘道之網路設計

Abstract

⼼電圖儀在臨床上是⽤來判定各種⼼臟疾病的⼯具，傳統的⼼電訊號測量必須在病患⾝上安裝有線的測量裝置，造成了患者⾏動上的不便。為了解決這個問題，開始有了利⽤低功率藍芽來達到無線傳輸⼼電圖的功能。不同於其他無線⼼電圖的系統只使⽤單導極測量⼼電訊號，我們使⽤了三導極測量並⽤⼀個演算法還原成⼗⼆導極的訊號，增加其準確性，然⽽使⽤了三導極也伴隨著如何同步的重⼤挑戰。三導極組成了⼀個獨⽴的近⾝網路，並且需要進⾏時間同步來完成後續的封包重組，還原出原始的⼼電訊號。每⼀個近⾝網路都會將收集到的資料放在緩衝區，等待物聯網閘道(IoT Gateway) 來接收資料後，將收集到的訊號資料上傳⾄雲端。⽬前還沒有任何研究能分析出在低功率藍芽的環境中，任意⼈數成功連線時所需要的時間。我們參考了多篇針對低功率藍芽連線延遲的分析研究，再加以修改來配合我們的系統環境，得到環境最⼤能服務的⼈數。此外，我們利⽤MATLAB 語⾔開發出了⼀套符合低功率藍芽規範的模擬器，能模擬在多個裝置競爭的狀況下造成的連線延遲，來與我們的理論值做⽐對。

Electrocardiograph (ECG) has been widely used for measuring electro-cardiac signals to diagnose and evaluate various types of heart diseases. Traditional ECG must place wired sensor on the patient, it makes patients feel inconvenient to move their body. Many studies have applied BLE by its convenience to make wireless ECG System. Unlike the usual, which use 1-lead ECG to collect data, we use 3-lead wireless ECG with an algorithm to recover signals to 12-lead ECG signals to improve its accuracy. As we use 3-lead ECGto collect data, it comes with a challenge to sync those three sensors. Every 3-leadECG form a body area network (BAN), in order to recover ECG signals, they need to synchronize their clock with each other. Each BAN will store data in their buffer, waiting for IoT gateway start polling those data and send to the cloud database. We have studied many other researches about the device discovery latency in BLE and accommodate to our designed system to estimate the capacity of network.