A real time ECG data compression scheme for enhanced bluetooth low energy ECG system power consumption

Wearable wireless medical devices have the ability to significantly improve medical care eco-system. Collecting detailed real-time bio-signals data can be straightforward and flexible by equipping patients with wearable devices. The bio-signal sending data through wireless connections which harvest most system power consumption represent one of the main challenges due to battery power limitation. Therefore, reducing the power consumption during wireless data transmitting leads to reduce size and weight of the device which make the patient comfortable especially in long-term medical monitoring. In this study, we present a system level compression scheme for enhancing real-time Bluetooth Low Energy (BLE) Electrocardiogram (ECG) monitoring and recording system. The system is designed and implemented for ECG data capturing and sending it at reduced power transmitting by employing discrete cosine transform (DCT) supported by threshold capability. It is supported by a state-of-the-art system-on-chip (SoC) BLE module as well as the ECG amplifier modules for the amplification process to achieve 6-channel ECG real-time bio-signal which is essential for more accurate and comprehensive diagnosis. A 3-volt Lithium coin cell battery is used to supply the proposed wearable system. The total current consumed by this prototype is further reduced from 2.1 mA (without applying compression algorithm) to 1.5 mA (with enhanced compression algorithm), that leads to extending battery life by 40% from 100 to 140 h. Due to its compact design and an extended period working time, this prototype provides a suitable low-cost solution for long-term monitoring approach in clinical as well as home telemedicine application. The prototype was tested to record various ECG signals for both normal persons and patients. Specifically, it has been tested to capture ten normal cases and 24 arrhythmia and ischemic heart disease in a clinical environment within a specialist heart hospital with satisfactory results.