Evaluation of a wireless vital sensor for ubiquitous health monitoring systems

Vital sensor and wireless information communication technologies play important roles in providing continuous health monitoring systems. The key elements required for the vital sensor device are its simplicity and accuracy, whereas those for the wireless communication tool are its connectivity and comfortability. For a commercially available wireless vital sensor with capability of measuring three-dimensional acceleration, electrocardiogram and body surface temperature, we conducted a clinical test for evaluating its accuracy and connectivity. The result of the clinical test revealed that the accuracy of the vital sensor was almost the same as that of the Holter monitor in term of electrocardiogram recording capability, but its wireless connectivity was much lower, that is, the average data loss rate was 0.22 for the data from all the subjects with variance of 0.025. In addition to the clinical test, we conducted an experiment on improving the wireless connectivity by receiver diversity in a patient room. The experimental result revealed that the average data loss rate, which was 0.041 for the use of a single receiver, was effectively reduced to 0.0023 only for the use of two antenna receivers.