Remote Health Monitoring Systems Based on Bluetooth Low Energy (BLE)
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mining approaches to diagnose user’s health status. In addition, authors in [28]
designed a low-cost healthcare monitoring IoT-based system with the Fog layer
sensing vital signs such as ECG, body temperature, and the respiration rate and
contextual data (i.e. humidity and environment temperature).
- Chronic Respiratory Monitoring Using Multi-sensing: James and all.
[22] developed BLE-based RHMS to monitor chronic respiratory disease that
sense multi-parameters. The system comprises a chest patch and a wristband.
The chest patch sensors corresponds to ECG, PPG, motion and acoustic signal.
The wristband sensors track ozone exposure, ambient relative humidity, ambient
temperature, PPG and motion. The data from each sensor is transferring by BLE
communication interface to the server for storage.
3 BLE Communication Protocols
3.1 Basic Concepts
Bluetooth v4.0 known as Bluetooth Low Energy is ideal for applications requiring sporadic or periodic transfer of small amounts of data. Thus, BLE is well
suited for sensors, actuators and other small devices requiring low power consumption. BLE works well with high numbers of communication nodes with
limited latency requirements, very low power consumption and short connection times and wake-up. BLE aims to provide the same communication range
as classic Bluetooth while consuming less power. The most significant differences between BLE and Classic Bluetooth are (1) the BLE has a lower data
rate, (2) BLE use just 40 channels (37 for data and 3 for advertising) instead
of 79, (3) no support for audio and (4) simplified state machines. Both BLE
and Classic Bluetooth, operates in the 2.4 GHz ISM (industrial scientific and
medical) frequency band, precisely BLE frequency band range from 2.402 GHz
to 2.480 GHz. To minimize the overlapping with other IEEE 802.11 channels,
the three advertisement channels (37, 38, and 39) centered on 2,402 GHz, 2,426
GHz and 2,480 GHz. Advertising is a process required for devices to find each
other. At the link layer BLE device, function as a state machine with four states:
standby, scanning (master procedure), advertising (slave procedure), initiating
and connection. Furthermore, BLE operates in piconets wit a star topology. The
central node is the master and all other nodes in the piconet are slaves. BLE
has an architecture client/server which the client can be the Master such as
smartphone, gateway, etc and the server is the peripheral such as sensors.
The connection establishement occurs after sending connection request
packet which handle connection parameters (connection interval, slave latency
and supervision timeout).
- Connection interval: corresponds to the time elapsed between two connection events. BLE devices are communicating only in connection events to
save energy. So bigger interval between those events will save more energy but
decrease data rate. No matter if device has data to send, it has to wait until
next connection event. The interval can be set from 7.5 ms to 4 s.
47
mining approaches to diagnose user’s health status. In addition, authors in [28]
designed a low-cost healthcare monitoring IoT-based system with the Fog layer
sensing vital signs such as ECG, body temperature, and the respiration rate and
contextual data (i.e. humidity and environment temperature).
- Chronic Respiratory Monitoring Using Multi-sensing: James and all.
[22] developed BLE-based RHMS to monitor chronic respiratory disease that
sense multi-parameters. The system comprises a chest patch and a wristband.
The chest patch sensors corresponds to ECG, PPG, motion and acoustic signal.
The wristband sensors track ozone exposure, ambient relative humidity, ambient
temperature, PPG and motion. The data from each sensor is transferring by BLE
communication interface to the server for storage.
3 BLE Communication Protocols
3.1 Basic Concepts
Bluetooth v4.0 known as Bluetooth Low Energy is ideal for applications requiring sporadic or periodic transfer of small amounts of data. Thus, BLE is well
suited for sensors, actuators and other small devices requiring low power consumption. BLE works well with high numbers of communication nodes with
limited latency requirements, very low power consumption and short connection times and wake-up. BLE aims to provide the same communication range
as classic Bluetooth while consuming less power. The most significant differences between BLE and Classic Bluetooth are (1) the BLE has a lower data
rate, (2) BLE use just 40 channels (37 for data and 3 for advertising) instead
of 79, (3) no support for audio and (4) simplified state machines. Both BLE
and Classic Bluetooth, operates in the 2.4 GHz ISM (industrial scientific and
medical) frequency band, precisely BLE frequency band range from 2.402 GHz
to 2.480 GHz. To minimize the overlapping with other IEEE 802.11 channels,
the three advertisement channels (37, 38, and 39) centered on 2,402 GHz, 2,426
GHz and 2,480 GHz. Advertising is a process required for devices to find each
other. At the link layer BLE device, function as a state machine with four states:
standby, scanning (master procedure), advertising (slave procedure), initiating
and connection. Furthermore, BLE operates in piconets wit a star topology. The
central node is the master and all other nodes in the piconet are slaves. BLE
has an architecture client/server which the client can be the Master such as
smartphone, gateway, etc and the server is the peripheral such as sensors.
The connection establishement occurs after sending connection request
packet which handle connection parameters (connection interval, slave latency
and supervision timeout).
- Connection interval: corresponds to the time elapsed between two connection events. BLE devices are communicating only in connection events to
save energy. So bigger interval between those events will save more energy but
decrease data rate. No matter if device has data to send, it has to wait until
next connection event. The interval can be set from 7.5 ms to 4 s.