MEDSATTelemedicine, Tele-education & Disaster Relief, an EWSSC Approach.

Konstantinos Karavasilis, Arnauld Nicogossian, Roald Sagdeev, Dennis Papadopoulos, Stamatis Kantartzis (University of Maryland), Calin Popovici (RSA, Ministry of Health, Romania), Franklin Chang-Diaz (Advanced Space Propulsion Laboratory, Johnson Space Center, NASA)

ABSTRACTThe new emerging areas of applications in Tele-Education and Telemedicine, promise to globalize quality education and bring a new dimension to health care. The major logistic problem in the global implementation of such services is the lack of adequate means of telecommunications throughout the Developing World, where these services are needed the most. MEDSAT is envisioned as a satellite telecommunication system for Disaster Relief, Telemedicine and Distance Learning and in this paper we describe the EWSSC approach of a ground based VSAT network, both fixed and transportable, in order to provide flexible and affordable access to space-telecommunication services. This concept intends to close the existing telecommunications gap for disaster relief, telemedicine, and tele-education aimed at developing countries with poor telecommunications infrastructure and remote/rural areas.

INTRODUCTIONIn the United Nations’ New Millennium report the U.N. Secretary General Mr. Kofi Annan

proposes “to harness new technology to the United Nations humanitarian purposes, with

plans to distribute medical information via the Internet to poor countries ” He promises a U.N. Information Technology Service to train groups in the developing world in the uses

and opportunities of information technology. This proposal is complimentary to a U.N.

plan to provide 10,000 Developing World hospitals with access to up-to-date medical

information via the Internet. Furthermore Mr. Annan guarantees that by 2015 all children

will receive an education. The major logistic problem in the global implementation of

such services is the lack of adequate means of telecommunications throughout the

Developing World, where these services are mostly needed. MEDSAT fills this critical

and important niche. Currently expanding cable (fiber optic) network is not going to provide access to the most needy in remote areas. The quick and affordable approach

requires the use of space telecommunications. Satellites in many cases offer the only

cost effective method of globalizing these new services within an acceptable timeframe.

Satellites are the enabling tool to reach beyond the geographic and cost restraints that

20th AIAA International Communication Satellite Systems Conference and Exhibit12-15 May 2002, Montreal, Quebec, Canada

AIAA 2002-1887

inhibit unlimited expansion of cellular, fiber and wire line communication. Furthermore,

satellites offer the most efficient means of broadcasting, that is, delivering information

from one point to multiple points.

TELEMEDICINE & TELE-EDUCATION

NASA has been involved in telemedicine programs since its inception. Distance

consultations have been used to insure astronaut’s health. NASA also requires earth

test-beds to validate its concepts and improve the practice of telemedicine for human

space flight. Thus, since 1970,

NASA has been testing its

telemedicine capabilities in

terrestrial applications and

providing feedback for its space

operations.

The following examples are key

features of terrestrial applications

in each of the last three decades

as shown in the two adjacent

figures.

NASA’s has two primary partners

in United States. The East-West

Space Science Center (EWSSC)

and the Medical Informatics and

Technology Applications

Consortium Commercial Space

Center, now located at the

Virginia Commonwealth

University. The third partner is

Moscow State University. These

partnerships were established to

develop, evaluate, and promote

telemedicine internationally for ground based and space applications.

All three partners are using Internet multicasting, and store and forward capabilities to

conduct consultations and distance learning.

1972-3STARPAHC

1975Applied Technology SatelliteCOSPAS/SARSATPEACESAT

1985 Mexico City earthquake

1989Telemedicine Spacebridge to ArmeniaTelemedicine Spacebridge to Ufa

1993ACTS-Demos

Spacebridge to Moscow

Background

Background (Cont.)1994GHnet (WHO/ PAHO/USAID/WB)

1995ARC telemed demo with Trident & Mt. Sinai Medical CenterSpacebridge to Russia

1997NASA Commercial Space Center theMedical Informatics and TechnologyApplications Consortium (MITAC)

1998

Andes/Ecuador surgery consult

Everest Extreme Expedition I

1999Virtual Hospital demonstration with ARCEverest Extreme Expedition II

NASA is a partner in another educational project in informatics with the East-West

Space Science Center (EWSSC) for international students. Using contemporary

teleconferencing software packages for phone and Internet, EWSSC faculty, visiting

international speakers, and NASA personnel conduct training sessions on telemedicine history, computer technology, telecommunications, and cross cultural communications.

To date, more than 55 scholars from these countries have completed their training in this

program.

The EWSSC has recently expanded its program with Uniform Services University of Health Services to include “Space and Public Health Sciences”. The curriculum includes

space policy, health policy, space medicine, informatics, cross-cultural communications,

and bioethics. In addition, EWSSC is currently developing the design of MEDSAT

satellites for telemedicine, disaster relief, and distance learning.

Challenges for Telemedicine services

• Information Systems

• Decision Support Systems

• Artificial Intelligence

• Compression

• Virtual Presence

• 3-D and 4-D Imaging • Computer-based Medical Training

• Computer-based Medical Records • Non-invasive Diagnostic Tools • Imaging

• Holography • Remote Sensing • Wireless Communications

• Appropriate Protocols and Procedures for Conducting Telemedicine • Overcoming Time and Distance Barriers

These challenges are further compounded by the need for technology to be small, adaptable, integrable, low power, low maintenance, and user friendly. In addition, the

culture, language, location and time zone difference must also be considered.

We outline next some basic preliminary considerations and options regarding the system ground design, traffic capabilities and network dimensioning under the constrain of the

limited available power from the satellite and suggest ways we can optimize the utilization of the system so as to limit the total cost of deployment and operation.

OBJECTIVE AND COVERAGE

The majority of the world’s population lives in areas prone to disasters. These catastrophes whether natural or anthropogenic, they disrupt administrative systems and destroy the infrastructure. Over the years disasters have struck dense population areas

globally with developing countries impacted more severely.The primary objective is to cover as much as possible of the populated land mass.

If we exclude the

Pacific, this can be achieved with just

two GEO satellites.

One over the Atlantic Ocean and one over the Indian

Ocean with one ground station linking the two

satellites.

There are two main types of coverage.

A broad (fixed) beam (e.g. with 4 feeds over Central and South America, Africa and NE

USA) for the satellite positioned over the Atlantic. A similar number of feeds is

configured for the

satellite over the

Indian ocean with

footprint over Eastern

Europe, Caucasus,

and Central Asia. A

high power steerable

beam on each

satellite can be

directed to a

particular area of

interest.

DESIGN SCENARIO

Approach in the design of the communications system is

• use of inexpensive, off-the-shelf components

• system robustness

• network flexibility for maximum use of bandwidth (bandwidth on demand, multiple

access, data compression)• standard protocol support for almost transparent operation and possibility of easy

interconnection with other public networks

• small size, low weight easily transportable equipment

• flexibility of fast and easy system expansion and/or reconfiguration based on

evolving traffic needs.

The proposed technical baseline for MEDSAT is small satellites in GEO assisted by

plasma propulsion. The advantages are summarized below.

• The use of small satellites provides for a considerably lower financial entry level to orbit. The cost per satellite with three transponders delivered to GEO is expected to

be approximately $15 million compared to the cost of a conventional Geo-stationary

satellite, starting from $140 million.

• The smaller the satellite (less transponders) the easier its access to orbital slot based

on the possibility of co-location next to a regular satellite.

• The critically innovative technological step for the MEDSAT project is the use of a

plasma propulsion module in order to replace the Apogee Kick Motor (AKM) for

delivering the satellite from Geo-transfer to Geo-stationary orbit and subsequently to

be used for N/S station keeping. The use of plasma thrusters serves for substantial mass saving and, reduces the delivery cost per transponder by up to 50%.

• Small (lighter) satellites, utilizing mass saving plasma propulsion do not need heavy

dedicated launchers for insertion into orbit. The launch to GEO accounts for

approximately 50% of the entire cost of a current satellite. MEDSAT satellites can be

delivered in orbit as secondary passengers (by piggy-backing) on heavy launchers

(with cost proportional to the mass). Another option is to utilize a whole new class of

smaller to medium size rockets that are substantially less expensive. The use of

plasma thrusters, in replacing or decreasing the size of the AKM brings another

advantage. Satellites can be launched from sites far from the equator, such as

existing sub-Arctic launch sites. In this case plasma propulsion would compensate for

the large amount of fuel needed in order to change the orbital plane.

Each satellite will carry minimum of 3 transponders, depending on the choice of the type

of satellite bus and launch configuration. Choice of Equivalent Isotropic Radiated Power

(EIRP) levels provides for convenient service parameters for a network of Very Small Aperture Terminals (VSATs), as a major component of the user’s ground segment.

Access will be based on Time Division Multiplexing (TDMA).

Well-established Traveling Wave Tube Amplifier (TWTA) technology provides for the

most efficient power to mass ratio in a given range of transponder parameters. The

MEDSAT satellites will operate in Ku-band with each transponder radiating 50 W of

power. Each transponder (36 MHz bandwidth) could provide for simultaneous service to

approximately 500 individual VSATs with a connection rate of 64 kbs. Actual bit rate

formats can be configured on demand going from 64 kbs incrementally to 1.512 Mbs (T1

line) and up to 6 Mbs (full motion TV in MPEG standard).

GROUND INFRASTRUCTURE

A Very Small Aperture Terminals (VSAT) satellite network such as the one proposed for

MEDSAT will be designed to provide telephony voice, fax and data service between

remote locations and the public or private telephone network. Such a network typically comprises four subsystems:

• VSAT terminals

• Mini-Hubs which provide multi-channel capacity.Hubs which act as gateways between satellite channels and terrestrial networks

• a Network Management Station, which controls access and manages the satellite

resources.

The satellite network can be organized either as a star network, whereby all calls transit through a single central hub, or as a mesh network. The network management station

supports both architectures. The mesh network naturally minimizes satellite propagation

delay and satellite resources utilization since a ‘single hop’ connection is used between

VSATs, mini-Hubs and Hubs.

COMMUNICATION SERVICES

Telephony voice service

Telephony voice is generally the most used service. Voice data compression is used to

make the most efficient use of the satellite power and bandwidth resources. Two voice

qualities are usually offered to trade-off quality versus operating cost:

• toll-quality voice, with a subjective quality approaching that of conventional terrestrial

telephone lines. The voice signal could be compressed from 64 Kbit/s PCM to 8 Kbit/s PCM using the most recent ITU-TS G.729 compression algorithm.

• economy mode voice. The voice signal is compressed down to 4.8 Kbit/s (or lower

rates) for the most efficient use of satellite resources.

Real-time data service

Real-time Data service is also supported. For this service, the VSAT terminal can be connected to the COM port of a PC. The VSAT behaves exactly like a standard modem,

responding to the Hayes AT command set standard. For maximum efficiency, the data

stream is compressed on the fly using ITU-TS V.42 bis standard data compression. The

maximum uncompressed data rates are 2.4, 9.6, 14.4, 28.8 or 64 Kbit/s, depending on

the specific link budget. ITU-TS V.42 is also used for error correction, with an overall bit

error rate of 10-6.

Two connectivity services are offered, as illustrated below:

* Internet connectivity (baseline);

• PSTN dial-up connectivity (requires optional equipment at the Hub or mini-Hub)

According to COMSY’s Report 2000- Trends in the VSAT Industry

Internet connection

A new form of data communication is rapidly emerging: virtually all new data services

are provided via the Internet: E-mail, FTP file transfer, World-Wide-Web, even voice

mail. As the hub can be connected directly to the Internet (i.e. without dial-up access), it

is possible to provide a much more reliable data service to mobile subscribers.

Services will include the ability to broadcast, multicast, unicast and offer point to point

services. Multicast service can be either stored data delivered to a selected group at a specific

time and capacity (push) or a flow of information with a pre-defined capacity (streaming).

Unicast is a set of hybrid services. Observing the highly asymmetric capacity

requirement for Internet users, the system design is based on a hybrid technique using

terrestrial networks for Internet requests and satellite for the high-speed traffic from

Internet to the end user, where the user(s) are connected to the Internet or Intranet

either by traditional Public Switched Telephone Network (PSTN) or low capacity fixed lines. The satellite is then used to transfer, at high-speed, the requested data back to the

business customers within a LAN or to the end-user. The satellite service enables

transfer speeds of up to 45 Mbps making it ideal for ISP’s starting its local service, where

terrestrial broadband Internet access is not adequate.

Comsy’s Report 2000

Point-to-Point Service provides reliable, two-way, wide-band satellite communication.

where considerable savings can be made, particularly in areas where infrastructure is

not fully developed.

Fax service

2.4 and 9.6 Kbit/s group 3 fax service with direct connection to a standard fax machine

at the VSAT. This optional service requires additional equipment at the Hub or mini-Hub

for dial-up interconnection to the PSTN.

TRAININGBased on EWSSC experience it is important that hands on training will be provided

to the personnel of the organizations that participate. Continuing this training to the

health and academic institutions by encouraging the trainees to become the trainers is

intended to support the infrastructure, provide contacts, and continue to foster and

expand the established partnerships.

REFERENCES

1. Office of Life & Microgravity Sciences and Applications, NASA. Telemedicine History. http://www.hq.nasa.gov/office/olmsa/aeromed/telemed/history.html. Accessed Feb 1 2002. 2. Stewart DF. Medical care delivery in the U.S. Space Program. In: Holloway HC, Nicogossian AE, Stewart DF, eds. Dervay JP, Doarn CR, Teeter R, co-eds. First International Telemedicine/Disaster Medicine Conference, Proceedings, NASA Publications NP-207. Washington, DC: NASA Headquarters, 1993. 3. Doarn CR, Nicogossian AE, Merrell RC. Applications of Telemedicine in the United States Space Program. Telemed J 1998-4:19-30. 4. Medical Informatics and Technology Consortium website, http://www.meditac.com/. Accessed Feb 14 2002 5. East-West Space Science Center website, http://www.ewssc.umd.edu/mfd.html. Accessed April 2 2002. 6. Uniformed Services University of the Health Sciences website, http://www.usuhs.mil/. Accessed April 7 2002 7. Space Technology Applied to Rural Papago Advanced Health Care. NASA Publication JSC-09161. Washington, DC: NASA Headquarters, 1974: also, Bashshur RL, Technology Serves the People. Office of Research and Development. Indian Health Service, Tucson, AZ: 1979. 8. BBC News website, http://news.bbc.co.uk/hi/english/world/europe/newsid_285000/285158.stm. Accessed April 5, 2002 9. http://www.nsab.se/ Accessed April 1, 2002.