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PAPERS & DOCUMENTS
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CREATING
AN INEXPENSIVE, NARROW-BAND, MULTIFUNCTION S/L BAND EARTH STATION
FOR THE REMOTE PACIFIC ISLANDS
Best,
B., and Okamura, T. (1996) Creating an Inexpensive, Narrow-Band,
Multifunction S/L Band Earth Station for the Remote Pacific Islands,
Proceedings of the Pacific Telecommunications Conference '96,
pp 574-581.
Table
of Contents:
1.
Abstract
2.
Introduction
3.
UOG PEACESAT
4.
PEACESAT MICRONET -- Distance Education Mission, Programs, Services,
and Needs
5.
Communications Needs in the Remote Islands
6.
General Approach to a Low Cost Education/Medical Satellite Delivery
System in Micronesia
7.
Functional Concept of a Digital Video Receive with Voice or Data
Return
8.
System Requirements
9.
Summary
Endnotes
Figure
1 (57 k)
Figure
2 (55 k)
Figure
3 (58 k)
1.
ABSTRACT
The
University of Guam PEACESAT (UOG PEACESAT) station provides
non profit public services to over a three million square mile
area of the tropical north Pacific, generally referred to as
Micronesia. Within this area, only 8 of over 200 significantly
populated islands (with a teacher or dispensary) have any off
island communication facilities, except for HF radio systems.
The outer islands of Yap, Chuuk, Pohnpei, and Majuro are more
populated, than the INTELSAT and PEACESAT (public service telecommunications)
serviced main centers. In order to network remote Micronesian
medical and educational facilities, small, robust, marine grade
narrow-band earth stations need to be developed.
This
paper presents a vision of rugged 3 meter S/L band earth stations
strategically located over the outer Micronesian Islands that
do not have INTELSAT or PEACESAT earth stations. These
simple solar powered narrow-band links would serve remote educational
and medical learning centers and would provide emergency communications
during environmental and natural disasters in coordinating state
relief workers. We hope that the industry could provide
a narrow-band single three channel (2 simplex and one duplex)
transceiver, hopefully digital, earth station that could provide
wide band receive only and simple voice communications, 9.6
KHz data transmission, and G-3 two way facsimile capability
for under US $15,000. The earth stations must be easy
to maintain and cost efficient to operate (space segment being
provided by PEACESAT at no cost to the qualified user). This
network would provide basic communications for the remote islands
until the LEO or "Spaceway" style GEO systems are
launched and are affordable to thin route Pacific Island countries
of the Federated States of Micronesia (FSM), the Republic of
Palau, and the Republic of the Marshall Islands (RMI).
2.
INTRODUCTION
The
University of Guam (UOG) is the only four year post secondary
educational institution located in Micronesia. UOG offers 26
baccalaureate degrees in four undergraduate colleges: the College
of Arts and Sciences; the College of Agriculture and Life Science;
the College of Business and Public Administration; and the College
of Education. In addition, the UOG Graduate School oversees
the offering of Master's degrees in the areas of art, biology,
business, education, and public administration.
The
student body is relatively diverse. It consists of students
from Guam, Micronesia, the US mainland, the Philippines, and
Asia. The present enrollment is approximately 5,500 students
at the main campus. In addition, the University offers a variety
of courses throughout Micronesia through its Center for Continuing
Education and Outreach Programs (CCEOP).
Micronesia
is about 3,000,000 square miles of ocean (more than 7 million
square kilometers) and 1,045.3 square miles of land (2,707.2
square kilometers). It runs from 2.39 degrees south to 20.33
degrees north for a maximum north to south distance of 1,387.2
nautical miles (1,595.28 statute miles). The east to west distance
is approximately 2,726 nautical miles (3,135 statute miles)
lying between 131.10 degrees east and 176.54 degrees east. Thus
it covers an area that is roughly equal to that of the continental
United States (See Figure
1 (57 k) ).
Within
Micronesia, UOG has concentrated its efforts on the former American
flag territories. Today, these territories are divided into
five separate political jurisdictions: the Republic of the Marshall
Islands and the Federated States of Micronesia, both of which
are freely associated with the United States; the Commonwealth
of the Northern Mariana Islands and the Unincorporated Territory
of Guam, both U.S. Territories; and the Republic of Palau, the
remnant of the Trust Territory of the Pacific Islands.
3. UOG PEACESAT
The
primary role of the UOG PEACESAT is to provide public service
telecommunications to support the Micronesian educational and
medical communities.
As
a regional telecommunications hub, UOG PEACESAT handles most
of the emergency, disaster and medical evacuation traffic in
the region. UOG also delivers college courses and seminars over
the PEACESAT network to the constituents within the three million
square miles of Micronesia. Combining the use of the UOG PEACESAT
SSB radio, satellite RF technology, and distance education program
options, the UOG outreach program and the local community in
general have been able to communicate with the Micronesian region
more efficiently and effectively.
Some
of the emergency management users of UOG PEACESAT include the
Red Cross, Federal Emergency Management Agency, Centers for
Disease Control, and the Coast Guard Search and Rescue.
The
FSM Consulate routes medical referral communications to and
from Guam Hospital and FSM Hospitals through the UOG PEACESAT.
Telephone interconnections with SSB, HF radio, and the GOES
satellite systems help the FSM states in their typhoon recovery
efforts. The solar powered UOG PEACESAT was the primary source
of information to the outer areas of Micronesia after the Great
Quake on Guam (August 8, 1993). The GOES satellite and the SSB
high frequency radio links connect the most remote reaches of
Micronesia to the developed information centers around the Pacific
Rim.
4.
PEACESAT MICRONET -- DISTANCE EDUCATION MISSION, PROGRAMS, SERVICES,
AND NEEDS.
The
UOG PEACESAT provides public service, distance education and
Internet via satellite to Palau, Majuro, and the four emerging
island states of FSM and their respective outer islands of Micronesia.
The UOG PEACESAT also established and continues to operate a
HF/SSB network that reaches dozens of outer island schools and
dispensaries within Micronesia. UOG services provided to the
region include:
- MICRONET
news and weather (international and regional) are broadcast
daily from Guam, often directly into the local island's AM station.
- UOG
provides UOG College of Education courses to Rota (Commonwealth
of the Northern Mariana Islands, CNMI), the four states
in the FSM, the Republic of the Marshall Islands, and the
Republic of Palau. Most courses are live interactive voice
or on-site video with PEACESAT interactive voice lectures.
- The
UOG College of Nursing is currently providing interactive
digitized compressed video, electronic whiteboard and digital
voice over standard voice grade circuit to Palauan nurses.
This exciting new distance education delivery technology
is currently run over a Macintosh format and is interactive
with Palau Community College. We would like to expand this
service to other entities and organizations. Courses will
use land line modem connections for color digital transfers
combined with standard lectures that are delivered over
PEACESAT voice circuits. The College of Nursing and the
Palau nursing students produced short videos and exchange
them via Continental pouch.
- The
UOG College of Nursing is currently providing interactive
digitized compressed video, electronic whiteboard and digital
voice over standard voice grade circuit to Palauan nurses.
This exciting new distance education delivery technology
is currently run over a Macintosh format and is interactive
with Palau Community College. We would like to expand this
service to other entities and organizations. Courses will
use land line modem connections for color digital transfers
combined with standard lectures that are delivered over
PEACESAT voice circuits. The College of Nursing and the
Palau nursing students produced short videos and exchange
them via Continental pouch.
- All Distance Education services are supported by the UOG9 UNIX
Internet Services combined with facsimile and modem connectivity
provided through the PEACESAT system. R&D continues
on Packet/duplex/ethernet extensions over to interface
with the proposed PEACESAT Services Improvement Plan (SIP)
that will provide enhanceddigitized audio-video graphics
for superior distance education programming. Also, Guam
is currently seeking funds for training workshops and technical
development upgrade projects that will support all of the
Micronesian sites.
5.
COMMUNICATIONS NEEDS IN THE REMOTE ISLANDS
UOG
PEACESAT has been, and continues to be, committed to providing
services to the Micronesian region. Unfortunately, the current
communication environment does not allow UOG to provide support
to the outer islands.
The
remote islands, as stated earlier, are not served by the telecommunication
carriers within the region. The majority of the population base
in Chuuk, Pohnpei, Yap and the Marshall Islands are not in the
centers and are generally without any communication links to
the children and professionals in the schools and dispensary
facilities.
There are no Intelsat or PEACESAT earth stations at these remote
sites. The location of Intelsat earth stations on these islands
have not yet been deemed cost effective by carriers. Further,
the current PEACESAT earth stations are not configured to enable
UOG PEACESAT to provide the kind of services that it is prepared
to support in the remote islands of Micronesia.
The current PEACESAT earth stations support a single carrier
that can be used for voice or for data, but are not designed
for receiving compressed digital video at base speeds of 128
Kbps. The current PEACESAT stations are also more expensive
($35,000 with autotracker) than is possible for many of these
small islands to purchase.
Consequently, these remote islands only have HF and SSB communications
that are not fully reliable. There is a very strong need in
Micronesia for the development of a small, robust, marine grade
narrow-band earth station that works in conjunction with the
PEACESAT system.
6.
GENERAL APPROACH TO A LOW COST EDUCATION/MEDICAL SATELLITE DELIVERY
SYSTEM IN MICRONESIA
The
following vision is an effective, efficient, appropriate and
cost effective scenario to provide distance education and teacher
training curriculum communication links to the underserved population
centers in the outer islands of the emerging island nations
of Republic of Palau, FSM, and the Republic of the Marshall
Islands.
The vision is based on the use of the PEACESAT GOES-2 satellite.
The same scenario with proper hardware changes could use a commercial
C-Band or Ku band space segment. However, PEACESAT is appropriate
for distance education and medical conferencing as long as the
traffic is limited to non profit communications.
Currently, the PEACESAT Services Improvement Plan proposes to
upgrade specific sites to 6 meter digital earth stations (Okamura
and Mukaida, 1995, 1994) with wide bandwidth capability. This
scenario is fine for government centers such as Kolonia, Pohnpei,
Koror, Palau, Kwajalein/Ebeye area of the Republic of the Marshall
Islands, Garapan, Common wealth of the Northern Mariana Islands,
and the University of Guam where a high volume traffic conduit
is needed.
However, the large earth stations will cost up wards of U.S.
$250,000 each and will commit the hosting government agency
to a recurring maintenance and personnel cost. For the outer
islands of the FSM and the Republic of the Marshall Islands,
we hope that smaller, more appropriate systems can be installed
for 1/10th of the cost of a 6m earth station and serve as a
complement to the PEACESAT Hub Site network.
Commercial links will not be cost effective in these outer islands
until LEO's or super GEO wide area satellite phone exchanges
are launched and implemented sometime after the turn of the
century. With over 3 million square miles of ocean, only SSB/HF
radio and satellite networks may be cost effective within the
region in the near future. However, we are still not sure that
the final cost of these new LEOs and GEOs will be cost effective
for the outer islands in the region.
7.
FUNCTIONAL CONCEPT OF A DIGITAL VIDEO RECEIVE WITH VOICE OR
DATA RETURN
The
basic concept is to install and maintain a small learning resource
center in the more populated outer islands. Each class room
would be supplied with solar powered circuits with generator
back up for the audio-video computer integrated earth station.
All equipment would be DC input (12VDC VCR/ Monitors and computers
are currently available), and simple to operate and maintain.
The earth stations would be small, digital and capable of up
& down linking of 9.6 Kbps with 128 Kbps digital video receive
capability. The concept assumes that power required for wide
bandwidth transmit capability would not be cost effective and
therefore not sustainable. The wider bandwidth receive link
would allow the remote site to receive compressed color video
from the originating up link facility in Guam, Saipan, Pohnpei,
Hawaii, etc. A PC based, low speed video codec system would
be used for receiving programs.
Full G-3 fax and phone links will be available along with Internet
access and basically any communication device that is compatible
with a phone system that can be hung on the earth station. The
earth stations need not have more than 2 simplex (multiple site
teleconferencing) channels and one duplex channel. The VCR system
can show the prerecorded class tapes, and the remote classroom
can interact via the satellite link. The earth stations can
be installed for under U.S. $20,000 each and with local support
can be operated inexpensively thanks to the U.S. supported GOES
space segment.
In addition to the educational services a grant would fund,
emergency links will utilize the 'earth alert' hand held triggered
from UOG via satellite. When islanders receive an alert from
UOG, they will check the SSB for details from Guam. UOG can
design low powered FM broadcast stations that can be used for
distance education, cultural programs, primary health care workshops,
and would be available for emergency information dissemination
for Tsunami/typhoon locations, search and rescue, etc. This
scenario allows small $10 transistor radios to be at the homes
for monitoring the local atoll's solar powered FM broadcast
station, which can be fed to UOG PEACESAT Communications Hub
during emergencies or distance education programming.
Figures
2 and 3 contains a general pictorial representation of this
vision. Figure
2 (55 k) shows how the system would be interfaced to existing
HF and AM systems, as well as to emergency notification system
such as Earth Alert, currently being tested by NASA.
Figure
3 (58 k)shows
an inexpensive 6m mesh antenna to receive digital video and
have a data or voice return based on digital compression technologies.
The figure illustrates the conceptual application needs of UOG
PEACESAT, but does not need to be implemented with this specific
technology. Figure 3 also shows the existing PEACESAT 3m sites
as participating in network through 64 Kbps digital modems.
The key is not the technology that is identified but the ability
to meet requirements that are generally outlined below.
8.
SYSTEM REQUIREMENTS
The
following are some of the requirements and parameters of the
system.
7.1. GOES-2 Satellite Environment
PEACESAT uses the second of a series of Geostationary
Observation Environmental Satellite or GOES-2. The GOES-2 satellite
is in an inclined orbit to save fuel and located at 175oW. This
inclined orbit requires any system accessing the satellite to
constantly track its movement through a figure eight. The nominal
satellite position dimensions in the Year 2000 consist of:
- North-South
+/- 15.0o
- East-West
+/- 2.0 o
- 8.1.1.
The satellite link budget, based on the best available
information, is:
- Beam
center EIRP 54.4 dBm
- Downlink
beamwidth 19.6 o
- Earth
edge 2.4 dBm
- Earth
edge EIRP 52.0 dBm
- Multicarrier
EIRP 52.0 dBm
- Transmit
EIRP 35.4 dBm
- Transmit
EIRP Stability +/- 1 dBm
8.1.2. The system has a hard limited repeater and operates in
multicarrier mode. There must not be any interference or intermodulation
impacts to the existing carriers.
8.1.3. All performance measures must conform with the existing
PEACESAT frequency and carrier plan.
8.1.4. The azimuth of the earth station must be plus or minus
25 degrees. The GOES-2 has a global footprint. Earth stations
are located in Palau, Papua New Guinea, Australia, and Oregon.
All must be able to see the GOES-2 in its current location.
8.1.5. The earth station must have a dual axis auto tracker
to optimize on performance and minimize the level of operator
intervention.
8.1.6. The tracking system must be compatible with the existing
beacon receiver signal.
8.1.7. The operational frequencies for the GOES-2 satellite
are as follows:
Transmit: 2025-2034 MHz
Receive: 1683-1695 MHz
8.2. Cost
The proposed system should cost about $15,000. This does not
include the cost of the digital video receive only codec, microcomputer,
or other peripheral equipment.
8.3. Environmental Requirements
The Pacific island countries present several problems that must
be accounted for in the design. The earth station requirements
include design consideration of the following environmental
conditions or restraints.
8.3.1. The system must be able to operate with heat and humidity.
8.3.2. The system must be resistant to salt water that corrodes
metal.
8.3.3. The system must minimize the electronic components that
would be outside of a building.
8.3.4. Outdoor components must be protected and replaceable
in the field.
8.3.5. The antenna must have a survival wind speed of 125 miles
per hour.
8.3.6. The antenna must be capable of operating in winds gusting
to 60 miles per hour.
8.3.7. The tracking system must have memory and renewals, and
the use of a single step tracking capability.
8.4. Appropriate Technology
8.4.1. The system must be designed to use as much off the shelf
low technology as possible that can be installed, operated,
and repaired by electronics technicians.
8.4.2. The design must be based on field replaceable components
to minimize the repair and maintenance problems created by the
vast distances in the Pacific and the high costs of transportation
and time.
8.4.3. The design of the earth stations must enable technicians
in the field to diagnose problems without expensive test equipment.
8.4.4. Direct power must be used to interface with solar power
batteries.
8.5. Functional System
8.5.1. The system must be able to transmit voice or data and
receive digital video signals.
8.5.2 The system must be able to transmit data through multiple
access channels.
8.5.3. The system must have the teleconferencing capabilities
of a simplex channel.
8.5.4. The system must be able to interface with the existing
PEACESAT analog simplex channels.
8.5.5. The system must be able to receive a compressed digital
video receive only signal through the QPSK digital modulation
that PEACESAT uses.
8.5.6 The system must be able to support phone patching through
the PSTN.
8.5.7 The system must have standard audio interfaces for microphones
and for speakers.
8.6. Technology
8.6.1. The system must support widely used component parts that
will not be discontinued.
8.6.2. The system must have a high reliability under the conditions
specified above.
9.
SUMMARY
The
outer islands of Micronesia are not well served despite similar
needs for medical and educational uses of telecommunications
as the main islands. Today, the outer islands are only served
via HF or SSB radio links. These links are unreliable.
We are hoping that it might be possible for industry or an international
funding organization to assist in the development of a system
that would enable these outer islands to receive some of the
programming that will be provided by the UOG and other PEACESAT
Hub Sites in the Pacific Islands region. The programming would
consist of voice teleconferencing, data and other information
access, and the ability to receive compressed digital video
at 128 Kbps.
In doing so, we will take a step toward ensuring that small
island communities will be able to participate in the benefits
of the revolution in telecommunications and information technology,
services, and programs.
BIBLIOGRAPHY
Okamura,
N. and L. Mukaida (1995, September) "Public Service Telecommunications:
PEACESAT," Pacific Telecommunications Review, 14-23.
PEACESAT Headquarters, Hub Site Request for Proposals,
November 14, 1994.
Okamura, N. & Mukaida L. (1994) "PEACESAT:
A Regional Telecommunications Alliance in Transition,"
Proceedings of the Pacific Telecommunications Conference '94,
811-819.
ENDNOTES
- The
opinions and the interpretations in this paper are those
of the authors and do not necessarily represent, nor do
they purport to represent, the views, opinions, or the
work programs of PEACESAT - Headquarters.
- The
idea of a digital video receive system was developed by
PEACESAT as part of its "Services Improvement Plan." Unfortunately,
it has not been developed given funding limitations.
- The
authors would like to acknowledge the assistance of Dr.
Norman Okamura, Associate Specialist, Social Science Research
Institute, University of Hawaii, in contributing to some
of these specifications.
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