Gianmarco Angius, Danilo Pani, Luigi Raffo, Stefano Seruis
DIEE - Dept. of Electrical and Electronic Engineering, University of Cagliari, Piazza d’Armi, 09123 Cagliari, Italy
Paolo Randaccio
Dept. of Physics, University of Cagliari, Cittadella Universitaria, Monserrato, Italy
Telemedicine, tele-home care, remote monitoring, ECG, DVB-T, MHP.
Typical telemedicine systems are usually PC based and in some cases they use expensive custom devices to
satisfy the system requirements. For tele-home care uses by elderly or untrained people, these type of solutions
are impracticable. As an example of user-friendly tele-home care system, in this paper we present the first tele-
home care application of DVB-T technology over standard home entertainment equipments and a prototypal
low cost microcontroller-based acquisition unit for 1-lead ECG. The usability and low cost of the system show
the potentiality of the approach.
In order to reduce the costs for both the patients and
the public administration, tele-home care systems are
today often used for clinical practice. They permit
to avoid the overcrowding of ambulatories for simple
routine examinations and, in the case of chronic pa-
tients that must be frequently monitored, to avoid the
costs and the waste of time of an ambulatory examina-
tion for simple physiological measurements that they
could easily perform at home, sending the recorded
data to the care staff in the appropriate department.
Howewer, these telemedicine systems are usually PC
based or use complex hardware and software prod-
ucts. Even if such technologies are quite popular to-
day, they are frequently used only by relatively young
people, which are not the primary tele-home care tar-
The Digital Video Broadcast Terrestrial (DVB-T)
technology, under experimentation in Europe, will be
the only terrestrial television system after 2012. By
the use of a cheap set-top box, it is now possible to
adapt the new transmission tecnology to the old TV
equipments. The set-top box is actually a simple com-
puter, normally embedding a RS-232 compliant port
connector, a smart card reader and a modem for the
return channel link. In principle, it is then possible to
define tele-home care systems based on such technol-
ogy where the user interface is represented by the TV
screen (output) and the remote control (input). This
paper presents an example of a such system based
on DVB-T technology with a cheap microcontroller-
based acquisition unit and a very user-friendly inter-
face well exploitable even by elderly people.
The remainder of this paper is organized as fol-
lows. In Section 2 a brief analysis about related works
is presented. In Section 3 the whole proposed system
is introduced; Section 4 deals with some details on
the prototypal 1-lead ECG Base Station, whereas the
application on the set-top box is presented in Section
5. Section 6 concludes this work.
The primary activity of telemedicine systems was
the transmission of diagnostic medical images using
television for medical consultation from physician to
physician in remote places. Recently, telemedicine
systems through the Internet via satellite have be-
come a reality by means of high throughput mixed
satellite-web communication channels. This Section
presents some home-oriented telemedicine projects
making use of DVB and Internet, without the claim
to be exhaustive.
The Interactive Satellite Multimedia Information
System (ISIS) project (Pierucci and DelRe, 2000), re-
alized a telemedicine system based on satellite com-
Angius G., Pani D., Raffo L., Seruis S. and Randaccio P. (2008).
In Proceedings of the First International Conference on Health Informatics, pages 31-36
munication for furnishing interactive services for res-
idential users together with the traditional TV distri-
bution, porting tipical applications developed for ter-
restrial network (Internet) to the satellite digital video
broadcasting technology (DVB-S). By a dualband ter-
minal, connected in uplink via Eutelsat satellite and
in downlink via the Italsat satellite, the ISIS system
provides a small and low-cost transceiver for sites
not connected to the Internet or connected only in
dial-up low-speed mode. Through his Java applica-
tion for the DVB-S transceiver, called Medical Envi-
ronment for Diagnostic Images (MEDI), the project
can manage a medical image database for remote ex-
pert consultation and so it demonstrated the feasibil-
ity of satellite-based interactive multimedia services
for telemedicine purposes.
In 2001, a multipurpose health care telemedicine
system with a base unit and a mobile unit was de-
veloped in Greece too (Kyriacou et al., 2001). At
patient’s home, the mobile unit allows the transmis-
sion of vital bio-signals and static images of the pa-
tient to the base unit at the physician site (office or
hospital). The mobile unit device is compliant with
some of the commercial main vital signs monitor and
it is able to transmit ECGs, non-invasive blood pres-
sure (NIBP), body temperature, percentage of arterial
oxygen saturation (SpO
) and heart rate. Based on the
TCP/IP protocol, the communication between the two
parts ensures safe data transmission and the possibil-
ity to use different telecommunication means (GSM
or satellite links).
Launched in January 2001, the Universal Remote
Signal Acquisition For hEalth (U-R-Safe) tele-home
care project (Mailhes et al., 2003), created a mo-
bile telemedicine system for home monitoring to be
used by elderly peaple and disabled patients in Eu-
rope. Via short range Wireless Personal Area Net-
work (WPAN), wearable ECG and SpO
sensors are
connected to a portable electronic device, able to
send the recorded data to a remote central through
the TCP/IP protocol and the wireless public network
(GPRS, UMTS and GEO satellites). The portable unit
is also capable of sending an alarm when patient fells
sick, falls or pushes a button.
The Standard and Interoperable Satellite Solution
to Deploy Health Care Services Over Wide Area
(HEALTHWARE) project (Loghelongue, 2007), is
an integrated project of the Aeronautics and Space
thematic priority of the 6th Framework Program
(FP6) for satellite telecommunications systems and
telemedicine applications. Thanks to the digital
video broadcasting - return channel by satellite (DVB-
RCS) technology, that offers satellite reception and
transmission capabilities from anywhere, the project
aims at developing and validating DVB-RCS based
telemedicine solutions. It will focus on the areas
of chronic respiratory disease, cardiology and oncol-
ogy, through four main applications: medical train-
ing, tele-consultation, second opinions and monitor-
ing and remote assistance at home.
Even if these systems are very interesting, none
of them owns the characteristics presented in Section
1, primarily the possibility to be used by untrained
people to perform single exams rather then continu-
ous monitoring, with an immediate visual confirma-
tion of the quality of the signal measurement. None
of them could be used by the patient to control his/her
health state through simple measurements even with-
out sending the exam to a remote care center.
Digital Television (DTV) uses digital encoding tech-
niques to broadcast video, audio and data contents to
a receiver in the consumer’s home (set-top box). In
order to add multimedia information to the normal
television program, the Multimedia Home Platform
(MHP) allows the user to actively interact with the TV
(Interactive TV) obtaining useful services and infor-
mation. Based on the JavaTV platform, an extension
and standardization of existing Java APIs in the con-
text of DTV, MHP enables the interaction between the
interactive applications and the set-top box by a soft-
ware interface (middleware). Over a Virtual Machine,
JavaTV applications (called Xlets) run in the set-top
box with the support of a real-time Operating System
(OS), which provides all the functionalities required
including hardware resources access.
3.1 System Overview
The proposed system is depicted in Figure 1. The pa-
tient must own a TV, a DVB-T set-top box (with its
remote control) connected in uplink to the telephone
line, a personal smart card and a simple Base Sta-
tion unit for bio-signals acquisition. The Remote Care
Center (RCC) instead, has only a simple PC acting as
TCP/IP server,since the patient’s set-top box can send
through the Internet the result of the exams.
The Base Station is a simple microcontroller-
based acquisition unit to perform the digital biosig-
nals acquisition. It is connected to the set-top box
for data visualization and transmission, and it is con-
trolled by it and then indirectly by the user only
through the set-top box remote control, then simpli-
fying the overall procedure.
Application broadcast
Remote Care Center
TV & set-top box
Base Station
personal smart card
mhp Homecare
patients home
set-top box
remote control
Figure 1: A schematic representation of the proposed DVB-
T system for tele-home care.
The smart card, which must be programmed by
the RCC, is used to identify the patient providing all
the information needed to carry out the proper ex-
ams sending them to that RCC. The adoption of the
smart-card for user authentication and to provide to
the Xlet the required information about internet con-
nection and RCC server IP address, avoids the patient
to keep in mind or annotated elsewhere such informa-
tion, improving the system usability. It also enables
the personalization of the Xlet for the single user,
since the exams that can be performed are only those
programmed in the smart-card by the care staff. Since
the largest part of DVB-T set-top boxes has a smart
card reader (normally used for the pay-per-view ser-
vices), no hardware on the base station is required to
add this functionality.
The DVB-T MHP set-top box is like a computer,
characterized by an input channel from user (the re-
mote control), an output channel for the user (TV
screen) and some ports to allow its interfacing with
other devices, namely a serial port (RS-232) and an
RJ-11 connector for the telephone line (since the set-
top box has an internal modem), beyond the tradi-
tional audio/video connectors. The application pre-
sented in this paper has been tested on a Telesystem
TS7.4DT set-top box, with the version 21p1 of the
producer’s software, and implementing the MHP 1.02
profile with some enhancements, primarily the addi-
tion of java packages for both the smart card and the
serial RS-232 port management. The real-time OS is
Osmosys. To interact with the base station, the set-top
box uses the RS-232, whereas to send data to the RCC
the integrated modem is used. In the proposed system
the connection is in dial-up, so that it is surely simpler
to have this facility in every home compared to broad-
band connections. The Xlet application is loaded into
the set-top box by means of a broadcast transmission
provided by a broadcaster, so that successive releases
of it can be updated without the user’s intervention.
3.2 Patient’s User Interface
The graphic user interface (GUI) of the Xlet (hereafter
called MHPHomecare) is user-friendly and intuitive,
so that the patient can easily control the application by
means of the remote control. The user can explore the
application moving through the different full-screen
frames (hereafter called FSFs), choosing among the
possible options and functions by means of the remote
control keys, as if it would be a PC keyboard. Three
of the full-screen frames are generic whilst there is
another FSF for each exam. The three generic FSFs
the primary FSF, the first FSF shown when the
application is started. It waits for the smart card
insertion in the set-top box for user authentication
and then it shows the patient’s name (storing the
other authentication data only for the transmission
purposes), waiting for patient’s commands. It is
possible to close the application only from the pri-
mary FSF.
the about FSF, that shows the application credits
and can be launched only from the primary one;
the reduced FSF, that corresponds to the window
minimization to allow the patient to watch a TV
program while the application is running in back-
ground. It can be launched from every FSF.
Figure 2: The ECG exam screen of the MHPHomecare ap-
plication (ECG Exam FSF). The image has been acquired
by means of a frame grabber from the set-top box video
output, resulting in a poor quality and in altered colors.
In this application we used a simple 1-lead ECG to
test the whole system, so there is only another FSF (a
screenshot of this FSF is shown in Fig. 2), ECG exam.
It enables the ECG acquisition and shows in real-time
the samples acquired from the Base Station and all the
other information sent by it about the current exam,
such as the hearth rate (in bpm) and a warning mes-
sage in case of poor quality signal. Once the exam has
been saved, from the same FSF it is possible to send
it to the server of the RCC, to review it on the TV
(with zoom and scroll functions), to save a new exam
or to return to the primary FSF. The patient can inter-
act with the application moving through the different
FSFs as depicted in Fig. 3.
primary FSF
Smart card
not recognized
or not inserted
valid smart card insertion
User authenticated.
Waiting exam
acquisition start
or back command
ECG exam FSF
Start application
Real time plot of the
ECG signal. Signal
Sending data to the
remote care center.
Signal review, scroll
and zoom
Exit application
Exit application
valid smart card extraction ECG exam selection
start acquistion
send exam
Figure 3: The interaction scheme between the patient and
the set-top box application.
In order to test our system we realized a simple
microcontroller-based Base Station to acquire the pa-
tient’s bio-signals. The Base Station is a black-box
for the patient, and he cannot interact with it beyond
the on/off power supply switch. The Base Station is
battery powered, for simpler use and improved patient
safety, and can include a different number of sensors
and acquisition circuitry to serve different remote ex-
amination needs.
In the prototypal version presented in this work, it
implements a single channel electrocardiogram (lead
I) and consists in a classical ECG amplifier coupled
with a very simple and low cost Digital Signal Con-
troller (DSC), i.e. the Microchip
This is a 16-bit 30MIPS DSC enhanced with DSP
hardware, such as a 17-bit x 17-bit multiplier, a 40-bit
ALU, two 40-bit saturating accumulators and a 40-
bit bidirectional barrel shifter. It also provides several
embedded peripherals such as a 12-bit successive ap-
proximation analog to digital converter, and an US-
ART, both of them employed in this prototype. The
Base Station scheme is depicted in Fig. 4
Figure 4: A schematic representation of the prototipal 1-
lead ECG base station.
The fundamental characteristics of the Base Sta-
tion (frequency bandwidth, sampling frequency and
the number of bits of the A/D converter) are chosen
according to the recommendations of American Heart
Association for standardization and specifications in
automated electrocardiography (Bailey et al., 1990).
The ECG amplifier is a low-pass system with a vari-
able gain up to 2000 and a cutoff frequency of 100
Hz. It consists of an optically isolated instrumentation
amplifier with high CMRR connected to the wrists of
the patient and a simple inverting operational ampli-
fier connected to the right ankle for electromagnetic
coupling noise rejection purpose, so that only 3 dis-
posable (or reusable) electrodes are needed. The DSC
is programmed to sample the ECG signal at 250 Hz,
and it is interfaced through its internal USART to the
DVB-T set-top box.
According to the international recommendations
about the patient’s safety, the physical connection be-
tween the Base Station and the set-top box is repre-
sented by an infrared (IR) link. The Base Station em-
beds a module for the IR transmission of the serial
stream, whereas the set-top box exploits an external
IR coupler connected to the RS-232 serial port.
In order to reduce both the residual 50/60 Hz en-
vironmental electrical noise we have implemented a
digital notch filter, whereas a high-pass digital FIR
filter (cutoff frequency 0.05 Hz) was added for the
baseline drift elimination. All these computations are
performed in real-time on the Base Station, since the
set-top box is quite slow in processing due to the Java
VM and to the applications running on it. On the Base
Station has been also implemented a simple QRS de-
tector for heart rate calculation and visualization on
the TV screen (Friesen et al., 1990). The RR interval
measurement is performed sample by sample, and if
it is too far from the standards a warning code is sent
to the set-top box to ask the user to control the correct
connection of the electrodes. The average heart rate is
sent when the acquisition stops and is referred to the
average RR during the acquisition window.
MHPHomecare is a standalone application composed
of several threads. It enables the non-simultaneous
acquisition from the Base Station of an ECG exam,
its visualization on the TV screen, and its sending via
modem to the RCC where a server receives and stores
the exam.
5.1 Graphic User Interface Thread
Taking into account the differences between PC and
TV graphical applications, beyond the Java Abstract
Window Toolkit (AWT), also the HAVi (Home Au-
dio/Video Interoperability) API for graphic interfaces
have been used (Java, 2007). We used Tiresias as de-
fault font, which has been created specifically for the
TV screen, providing high readability and basing on
the Western European ISO- 8859-1 fonts set.
A specific thread is in charge to create the objects
related to the graphic elements composing the differ-
ent FSFs of the application, and it shows/hides them
depending on the current FSF.
5.2 Smart Card Management for User
The smart card is read by means of the SATSA (Se-
curity and Trust Services API) classes (Satsa, 2007),
that represent the new standard for smart card access
in Java. To access the smart card, we used the meth-
ods based on the APDU (ISO7816-4) protocol, but
the byte constituting the APDU strings are relative to
the ACOS2 microprocessor card by Advanced Card
Systems Ltd. To read the information stored into the
memory of the card it is necessary to provide the CXS
code to the method that opens the APDU connection,
since the smart card is not a JavaCard (Dvt, 2006). A
User Data File on the smart card stores the patient’s
name and its Personal Identification Code, the treat-
ing physician’s name and its Identification Number,
a permission exam code, some information about the
ISP (user ID, password, telephone number) and the
server IP address.
A thread, that is active in the primary FSF, ver-
ifies the correct insertion of the smart card into the
reader, hence reading the User Data File. If the card
is not properly inserted and recognized, the Xlet re-
mains blocked on the primary FSF. Once the card has
been recognized, the permission exam code is used to
allow the user to perform only some specific exams
among those available, hence disabling all the other
5.3 Serial Port Management for Exam
The serial port control is possible by means of the
package, available on the set-top box
used in this application. The communication fol-
lows analogue principles we can find in
and the serial port behaves according with the RS-
232 standard. A thread manages the communication
through it.
The set-top box sends to the Base Station the com-
mands to start the acquisition and to stop it. Both
such commands are simply 1-byte words. The “start”
command word is logically divided in two parts, i.e.
the actual command to enable the serial port trans-
mission, and a code that identifies the exam the user
chose by means of the Xlet application. The set-top
box receives from the serial port the samples of the
current exam in frames composed of N samples each,
where N changes from exam to exam as a function of
the sample rate. The application deals with 8 or 16-
bit signals (the data are stored in arrays of short). In
the current implementation only the ECG is available
on the Base Station, and it is acquired at 250 sam-
ple/sec, 16 bit/sample. With such sample rate and data
width, the maximum re-painting rate of the graphic
area where the signal is plotted is 200ms, which in
turn means that a frame of input samples must consist
of minimum N = 50 samples.
After the exam stops with a “stop” command
word, the Base Station sends to the set-top box a last
word with the value of the heart rate expressed in
bpm so that the Xlet updates with this information the
proper FSF.
5.4 Modem Management for Exam
A specific thread is in charge to manage the modem,
and it operates by means of the
package (Java, 2007), jointly with the
packages. The operations performed by
means of these packages are: ISP number dialing, ISP
authentication and TCP/IP data transfer towards the
server by means of a socket opening.
The user can start the transmission to the RCC
from the exam FSF simply pressing a key on its re-
mote control. In response to this action, the thread
establishes the connection with the ISP using the in-
formation previously read from the smart card. Once
the connection with the ISP has been established, the
thread opens a client socket specifying the IP address
of the server of the RCC. This IP address is read from
the smart card too, since different users need to send
their exams to different RCCs. At this point, the
thread sends a stream composed of two main parts:
the patient’s data and the exam data (collected during
the acquisition phase). Once the whole data stream
has been sent, the connection is closed and another
exam can be acquired.
In this paper, a DVB-T framework for tele-home care
was presented along with its prototype implementa-
Thanks to the DVB-T set-top box, which is very
similar to a computer with the possibility to be pro-
grammed, the system can interact with external cus-
tom peripherals and can be connected to the web.
Easy to use by people not skilled in digital electron-
ics, and since tele-home care is mainly used to mon-
itor elderly people which eventually falls in the pre-
vious category, pushed by the imminent deadline de
fined by the UE for the switch-off of the old ana-
log broadcasting transmission system, such tele-home
care framework could represent the best solution in
terms of quality and costs. Compared to traditional
systems, the presence of a visual environment on the
TV screen allows a more friendly use providing also
more detailed information and feedbacks about the
signal quality, and guiding the user through all the
exam procedure without any required printed manual.
Experimental results show the high potentiality of
the proposed solution and deserve further improve-
ments such as the development of a more powerful
base station (or a set of different base station models),
the realization of a digital broadcasting system, and
the extension to the official sanitary card, currently
under trial in some Italian regions and in other Eu-
ropean countries. It is actually under test a complete
Visual application to read and analyze the exams on
the Remote Care Center.
This work is part of the Personal e-Care project,
which has been partially founded by INFN, the Nu-
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