Wireless vital signs monitoring system for ubiquitous healthcare with practical tests and reliability analysis

Abstract The main objective of this thesis project is to implement a wireless vital signs monitoring system for measuring the ECG of a patient in the home environment. The research focuses on two specific research objectives: 1) the development of a distributed healthcare system for vital signs monitoring using wireless sensor network devices and 2) a practical test and performance evaluation for the reliability for such low-rate wireless technology in ubiquitous health monitoring applications. The first section of the thesis describes the design and implementation of a ubiquitous healthcare system constructed from tiny components for the home healthcare of elderly persons. The system comprises a smart shirt with ECG electrodes and acceleration sensors, a wireless sensor network node, a base station and a server computer for the continuous monitoring of ECG signals. ECG data is a commonly used vital sign in clinical and trauma care. The ECG data is displayed on a graphical user interface (GUI) by transferring it to a PDA or a terminal PC. The smart shirt is a wearable T-shirt designed to collect ECG and acceleration signals from the human body in the course of daily life. In the second section, a performance evaluation of the reliability of IEEE 802.15.4 low-rate wireless ubiquitous health monitoring is presented. Three scenarios of performance studies are applied through practical tests: 1) the effects of the distance between sensor nodes and base-station, 2) the deployment of the number of sensor nodes in a network and 3) data transmission using different time intervals. These factors were measured to analyse the reliability of the developed technology in low-rate wireless ubiquitous health monitoring applications. The results showed how the relationship between the bit-error-rate (BER) and signal-to-noise ratio (SNR) was affected when varying the distance between sensor node and base-station, through the deployment of the number of sensor nodes in a network and through data transmission using different time intervals