INFORMATION MANAGEMENT AND COMMUNICATION

EEG, ECG, EMG (eye

H. Data Transmission to IoT Gateway

VI. INFORMATION MANAGEMENT AND COMMUNICATION

As aforementioned in Concept and Structure the IoT- gateway takes up a central role for the communication to available data sources and consequently for the individual data collection (see Figure 5). Thus, elementary functions of the p

²

Health-Cloud regarding the data handling are delegated to the IoT-gateway. This requires that the p

²

Health-Cloud transfers comprehensive control information (measurement tasks) to the IoT-gateway including the available data sources, the required measurement parameters, data formats, pre- processing, and upload intervals (e.g. every day, hour or minute). All data-sources-related information is handled user- specific in a sensor table. Every IoT-gateway provides an individual, which consists of all required sensor configurations and options, access and callback URLs, tokens, IDs, parameter priorities and access limits. This is the base for the IoT- gateway to establish the connections, to configure the sensor devices, and to plan the access time, when access limits are declared. Access limits solely occur for the external clouds and can be for example restrict the communication on 150 requests per hour (for more complex data sets several requests are required). The sensor table can be updated by the p

²

Health-Cloud if changes in the data source configurations occur. After receiving the investigation-relevant information the IoT-gateway tries to establish a connection to the required and declared data sources (for physical, physiological and

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Fig. 6: Ubiqsense: data processing and strategy of operation.

environmental data). Additionally, priorities regarding the data sources (set by authorized in charge, medics) are considered when data (e.g. heart rate) from several sources are available.

The system communication including the communication to external data clouds can be divided into two general groups (as indicated in Figure 2):

Short-range communication – for the sensor-gateway communication blacktooth / BLE is used.

Mobile Internet communication – for the communication between the gateway and the involved cloud-solutions WLAN, G3 and higher is used.

The communication to the cloud solutions (Fitbit, Nokia or Garmin) as well as to the p

²

Health-Cloud bases on an API (Application Programming Interface). All of these solutions use the OAuth 1.0 (Garmin) or 2.0 (p

²

Health-Cloud, Fitbit, Nokia) authentication, HTTPS (Hypertext Transfer Protocol Secure) and anonymized data. The used protocols base on JSON and utilize vendor-specific structures and conventions.

Data sets from the external cloud solutions can be requested every time for a defined data and time range (also several days or weeks from the past). The data request to the external clouds is always initiated when a data transfer to the p

²

Health-Cloud is expected according to the measurement tasks. For the short-range communication the registered sensor-nodes are connected with the investigation start.

Currently, the IoT-gateway supports sensor nodes with BLE (by GATT - generic attribute profile) and Classic blacktooth as well. Possible configuration options (different data modes or individual parameter selection; available by the sensor table) are used to optimize the data traffic regarding the transferred data amount and consequently power consumption and to adjust the measurement process (parameter selection,

thresholds etc.) according to the current measurement tasks.

Usually this configuration options are offered by sensor nodes, which support comprehensive scopes of parameters.

If available, at the beginning a current sensor nodes time stamp is requested to recognize possible time differences with the IoT-gateway. This time offset is stored to enable the synchronization of all received measurement data together.

The measurement data of the directly accessible sensor nodes

are collected continuously, which also includes appending

the time stamp (if it is not offered by the sensor). The data

collected from the different sources are prepared by the IoT-

gateway regarding the reformatting, possible pre-processings

(e.g. conversion of units or mean value formation for defined

state intervals) and the data synchronization. The acquired

measurement- and process-data sets are structured in a JSON-

format (JavaScript Object Notation) and transferred to the

p

²

Health-Cloud depending on the orders in the measurement

tasks. These data sets build the base for the higher level-data

fusion by the p

²

Health-Cloud. To protect the privacy of the

users the data transmission is secured in both short (e.g.,

BLE) and long-range (e.g., WiFi) data communication. The

Ubiqsense has been developed on nrf51822 microcontroller

(Nordic semiconductor) which supports the Advanced

Encryption Standard (AES) HW on the node for data

encryption. In long-range data transmission, the anonymity

is applied between IoT-Gateway and S&N − Cloud. In

addition, separated connections via appropriated services

are used for the data exchange between the p2Health-

Cloud and the provider-cloud-servers. HTTPS is utilized

for data transmission the provider-cloud-servers; the data

are anonymized. For the communication between the p2

Health-Cloud and the IoT-gateway also the OAuth 2.0

authorization as well as HTTPS and anonymized data are

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0 100 200 300 400 500 600 700 800

Sequence of samples 0

5 10 15 20 25

NO2(ppm)

0 500 1000 1500 2000 2500

Sequences of samples 30

35 40 45 50 55 60

Noise (db)

0 200 400 600 800 1000 1200

Sequence of samples 52

54 56 58 60 62 64

Air humidity(RH%)

0 200 400 600 800 1000 1200

Sequence of samples 25

25.5 26 26.5 27 27.5 28 28.5 29 29.5

Temperature (°C)

Fig. 7: Transmitted parameters from Ubiqsense to the smartphone and server.

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0 10 20 30 40 50 60 70 80

Sequence of samples 74

76 78 80 82 84 86 88 90 92 94

HeartRate(bpm)

0 10 20 30 40 50 60 70 80

Sequence of samples 6

8 10 12 14 16 18 20 22

RespirationRate (bpm)

0 500 1000 1500

Sequence of samples 0

200 400 600 800 1000 1200 1400 1600 1800 2000

rrInterval(ms)

0 10 20 30 40 50 60 70 80

Sequence of samples 26

26.5 27 27.5 28 28.5 29 29.5

Skin temperature (°C)

Fig. 8: Transmitted parameters from Equivital to the smartphone and server.

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JOURNAL OF L^ATEX CLASS FILES, VOL. 14, NO. 8, AUGUST 2015 16

Fig. 9: Test person wearing Fitbit, Ubiqsense and Equivital during the demonstration of the experimental tests.

used. Our solution supports the data compression as well.

Furthermore, the secure data transmission is followed and

supplemented with authorization. In the authorization process

a token is generated, which allows access to the customer’s

data (Fitbit: OAuth 2.0, time-limited tokens of one or eight

hours,refreshing tokens available; Nokia: OAuth 2.0, no time

limits for tokens) [55].