A commercial mobile satellite system which is to be constructed and operated in Canada is examined. This is done in two phases. First, mobile data services was introduced. Hub equipment and 3000 mobile data terminals were supplied. Over the satellite tests were performed. The mobile data service provides full two way digital messaging automatic vehicle location and fleet management services. The second phase is to construct, launch and make operational the MSAT satellite and associated network control facilities. The implementation is examined of the mobile data service in Canada, including the technical description. Marketing and applications are also examined

Egan, Glenn R.

Sward, David J.

English

NASA Technical Reports Server

N92-24196
Satellite Mobile Data Service
for Canada
Glenn R. Egan and David J. Sward
Telesat Mobile Inc.
333 River Road
Tower A, 14th Floor
Ottawa, Ontario
K1L 8B9
Telephone: (613) 746-5601
Facsimile: (613) 746-2277
ABSTRACT
Telesat Mobile began commercial
operations on December 15, 1988 with the
signing of a shareholder agreement
between Telesat Canada, Canadian Pacific
Ltd. and the C. Itoh Group of Japan.
TMrs mission is to construct and operate a
commercial mobile satellite system in
Canada. This will be done in two distinct
phases.
First, TMI will introduce mobile data
services in June, 1990. A contract has
been awarded to Canadian Astronautics
Ltd. supported by Gandalf Systems Ltd.
and Hughes Network Systems for the
supply of hub equipment and 3,000 mobile
data terminals. Over-the-satellite tests
began in February, 1990. The mobile data
service will provide full two-way digital
messaging, automatic vehicle location and
fleet management services.
The second phase is to construct, launch
and make operational the MSAT satellite
and associated network control facilities.
This paper will focus on Phase I, i.e. the
implementation of a mobile data service in
Canada. in addition to a technical
description, the paper will provide
information on markets and applications.
BACKGROUND
The Canadian Mobile Satellite system
(MSAT) is approaching completion after
almost ten years of planning. The Federal
Department of Communications pioneered
the technical and commercial development
of MSAT from 1983 to 1986. Telesat
Canada worked closely with the DOC
during this period. Telesat Mobile Inc.
(TMI) was later formed in December, 1988
to fulfill the mandate of implementing
mobile satellite services in Canada.
TMI's business plan is based on
providing a North American service
through joint operations with a licensed
American mobile satellite operator. In
May, 1989, the Federal Communications
Commission authorized the American
Mobile Satellite Corporation (AMSC) to
provide mobile satellite service in the
United States. In April, 1990, TMI and
AMSC formally entered into a Joint
Operating Agreement which provides a
solid foundation for implementing a North
American system.
TMrs major shareholders are Telesat
Canada, Canadian Pacific Ltd. and the C.
Itoh Group of Japan. Bell Canada
Enterprises Mobile (BCEM) also has a
financial interest in TMI and will distribute
MSAT products and services.
TMI plans to introduce mobile satellite
services in two phases. Phase I services
will be introduced during the construction
period of the MSAT satellite i.e. 1990 -
1993. These services include a mobile data
service for introduction in June, 1990 and
a "Stop and Talk" voice service planned for
introduction in June, 1991. Phase II
services will commence when MSAT is
commissioned in late 1993 and consist of a
full range of integrated voice and data
services under the portfolio name "mobile
ISDN".
International Mobile Satellite Conference, Ottawa, t990
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https://ntrs.nasa.gov/search.jsp?R=19920014953 2020-03-17T12:11:58+00:00Z
The mobile data service provides two-
way messaging, automatic vehicle location
and fleet management. A contract was
awarded to Canadian Astronautics Ltd. in
October, 1988 to provide hub messaging
equipment and vehicular terminals.
Gandalf Systems Ltd. and Hughes
Network Systems are major sub-
contractors to this program.
Satellite capacity has been leased
through Teleglobe Canada through
Teleglobe Canada to facilitate this service.
An INMARSAT satellite has been
repositioned to 106 W to provide coverage
of Canada and the U.S. Current plans are
to operate the mobile data service on this
satellite commencing late June, 1990. The
satellite coverage provided from the 106 W
position is shown in Fig. 1.
MOBILE DATA SERVICE
The mobile data system provides
solutions on an end-to-end basis. It is a
combination of two elements: a satellite-
based, packet-switched network and
network access systems.
The satellite-based, packet-switched
network provides data throughput, route
diversity, flow control of multiple network
access systems, and error detection with
error correction and data retransmission
algorithms. The network performs
functions similar to most packet-switched
networks that provide for reliable, error-
free transmission. (See Fig. 2.)
Additional value is offered to users of
the network through the flexible network
management system.
The network management and control
system supports the network as a whole as
well as individual fleets. Issues such as
network access authorization, radio
frequency assignments and overall system
fault detection, isolation and correction are
managed exclusively by Telesat Mobile
network operations staff.
Each element of the network is
redundant and fault-tolerant design
ensures continuous operation. Many
aspects of network management and
Fig. 1 Coverage from 106°W Longitude
140.0 130.0 120.0 110.0 90.0 80.0 70.0 60.0 50.0
LONGITUDEldeg)
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International Mobile Satellite Conference, Ottawa, 1990
/
Customer Central
Network Access Systems
• Dumb terminal
• Single user DOS PC
• Multi-user multi-tasking UNIX PC
• Sub-network controller
• Graphics subsystems
Fig. 2 Mobile System Data Connectivity
MQbile/Remote
Network Access Systems
• Hand-held driver terminal
• DOS Laptop/PC
• UNIX Laptop/PC
• Single-port PAD
• Multi-port PAD
control relate to the operation of a particular
customer fleet, and the network through
partitioning and secure network access
procedures allow individual customers to
directly manage their own fleet.
Prior to the launch of MSAT, L-band
space segment is at a premium. Telesat
Mobile has secured long term leases
through Teleglobe to support our program.
Efficient allocation of the space segment is
critical to providing uniform quality service
to several thousand mobiles. This is
achieved through segmenting data
according to its traffic profile and utilizing
multiple satellite channels, each optimized
to suit a particular type of traffic. The
network architecture supports regularly
scheduled reporting, demand access short
messaging and demand access file transfer.
Inbound traffic is routed via three
distinct channel types. Regularly
scheduled information such as vehicle
locations or remotely sensed data can be
transmitted on one of the position reporting
channels. Since all transmissions are pre-
assigned, extremely high efficiencies are
attainable on these channels.
Randomly scheduled short messages
are transmitted on one of the general
messaging channels. The satellite link
protocol utilizes a combination of random
access slotted aloha and pre-assigned
TDMA to transmit messages. Each frame
on the inbound channel is portioned into a
random access and pre-assigned segment.
This moveable "fence" separating the two
access schemes allows for system tuning
based on actual traffic patterns.
According to the total message length,
the message is divided by the mobile unit
into a number of packets. The first packet
is transmitted in the random access portion
of the frame and the remainder of the
packets is transmitted in the pre-assigned
portion. Information embedded in the
outbound channel informs all mobiles of
the upcoming slot reservations and
assignments. Demand access file transfer
is provided on dedicated circuit-switched
channels that allow for continuous packet
transmission.
Outbound messages are carried on a
TDM carrier. The carder utilizes variable
packet lengths in each 639 information byte
frame. This assures maximum utilization
of the high power forward carrier. The
outbound carder transmission rate is 1200
sps. The mobile units employ two speed
modems to support both 600 sps and 1200
sps transmission rates. (See Fig. 3.)
Network access systems are provided
at the mobile and organization's
central facility. These systems define the
real functionality of the service and provide
International Mobile Satellite Conference, Ottawa, 1990
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the user with transparent access to the
packet-switched network. Since the
interface specifications to the
network are open, a broad array of
network access systems are evolving.
The interface to the mobile portion of
the packet switched network consists of the
two RS-232 ports. Devices are currently
available to support simple message
creation, editing, storage, transmission and
receipt in a hand-held terminal. Laptop
computers and single user PC's are also
available. High end multi-user platforms
with extensive networking capability are
also provided to support more
sophisticated applications. The access
devices utilize DOS and UNIX operating
systems to allow the migration of existing
software applications to the remote or
mobile domain. This allows users to
continue to use familiar programs when
they move from the office to the mobile
environment.
Additional access devices are available
to support unmanned sites such as data
collection platforms or monitor and control
stations. Ranging from single port to
multi-port programmable, these devices
offer the flexibility required to support a
broad array of applications.
At the customer's central office,
network access is also supported by a
variety of systems. The most elementary
of these consists of a dumb terminal driven
by the network that provides full text
messaging and printing capability. Single
user DOS-based PC's and multi-user
UNIX-based micro-systems are also
available that support full text and data
messaging and powerful graphics displays.
Graphics systems may be modified by
customers to suit their own applications
and can be displayed on standard monitors,
high resolution monitors or full screen
projection systems. For customers with
existing unique applications, interface
specifications for message and file transfer
are provided, and integration support is
available.
DISTRIBUTION
TMI is in the process of establishing a
sales and support network for MDS
through agreements with value-added
resalers (VARs). VARs will provide a
local presence for sales and maintenance
functions. VARs' responsibilities may be
segmented by service type i.e. Road KIT,
Field KIT, or by geographic territory.
VARs also contribute significantly as the
name suggests to the "value" of the service
Fig. 3 Mobile Data System Elements
Inbound TDMA /__... Outbound TDM
Customer TMI TMI
M.I.S. Centre Messaging Hub
Facility Facility Mobile Earth Terminal
• radio
• antenna
• mobile access terminals
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International Mobile Satellite Conference, Ottawa, t990
Fig. 4 Distribution
National
Systems
VAR
Marine
VAR
Field
VAR
Road US
End Users
by providing specified access software or
custom MET interface devices. TMI has
entered into VAR agreements with Sea
Link Ltd. of St. John's, Nfld. and Munro
Engineering Ltd. of Calgary, Alta. (See
Fig. 4.)
CONCLUSION
The Phase I Mobile Data Service is an
important first step for Telesat Mobile.
MDS meets the needs of the transportation,
marine and SCADA markets by providing
wide area, reliable communications and
fleet management services. MDS will
allow TMI to establish a market presence
prior to the launch of MSAT and provide
an initial base of users for transfer to
MSAT when commissioned in 1993.
MDS is the first mobile satellite service in
TMI's eventual full service portfolio of
Mobile ISDN.
International Mobile Satellite Conference, Ottawa, 1990
A19


Satellite mobile data service for Canada

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