The European Space Agency is presently procuring an L band payload in order to promote a regional European L band system coping with the specific needs of the European market. The payload, and the two communications systems to be supported, are described below. The potential market for EMS in Europe is discussed

Ananasso, F.

Jongejans, A.

Mistretta, I.

Rogard, R.

English

NASA Technical Reports Server

N94-22789
THE EUROPEAN MOBILE SYSTEM (EMS)
A. JONGEJANS, R. ROGARD
European Space Agency
Postbus 299
2200 AG NOORDWIJK
The Netherlands
TEL: 31 1719 83142
FAX: 31 1719 84598
I. MISTRETTA, F. ANANASSO
Telespazio S.p.a
Via Tiburtina, 965
00156 ROME
ITALY
TEL: 39 640793738
FAX: 39 640793624
Abstract : The European Space Agency is presently procuring an L band payload in order to
promote a regional European L band system coping with tile specific needs of the European market.
The payload, and the two communications systems to be supported, are described below. The
potential market for EMS in Europe is discussed.
1 - INTRODUCTION.
The European Space Agency has developed and
launched elements of the first generation of Global
L-band satellites in the early 80's (MARECS-A
launched in 1981 and MARECS-B2 in 1984). From
1983 onwards, in the framework of the PROSAT Feederlink :
programme, extensive theoretical and experilnentai Mobile link :
work in the field of mobile satellite colnmunica[ions L-band :
was carried out, resulting in the design of two Land L-band G/T :
Mobile Satellite Conmmnication sytems and in the Ku-band G/T :
development of the EMS payload to be embarked on Usehd bandwidth :
the ITALSAT-2 satellite due for launch by mid-1995. Payload DC power :
Payload Mass
2 - EMS PAYLOAD
The optimisation of the space segment is a key issue
for a competitive land mobile voice service as the space
segment cost is predominant.This leads to the
requirement for efficient use of the radiated power
from the correct orbital position over the useful
coverage only. For Europe, an edge of coverage gain
of about 26 dB can be achieved with a single bealn
from a 13 deg east orbital position. Another key
element is the possibility to reuse the L-Baud
spectrum from this orbital position through the use of
CDMA techniques. A Eurobeam flw the feeder link
at Ku band offers the possibility of having a VSAT
station as Hub. Tbe EMS payload consists of two
transponders connecting the Fixed Earth Stations
(FESs) at Ku-band with the Mobile Earth Stations
(MESs) at L-band and vice versa. The main
characteristics of the EMS payload are summarised
below:
Ku-band
L-band
42.5 dBW
-2 dB/K
-1.4 dB/K
12 MHz
400 W
60 kg
EMS characteristics
In order to facilitate coordination with other L-band
satellite networks and to allow flexible handling of
the payload capacity, the total useful bandwith has
been divided into independent sub-bands. In the
fi_rward link the total useful bandwidth consists of
three 4 Mllz bands.In the return link, where the
interference problems are most acute, each of the
above three bands has been further divided into four
channels each, of 1 Mhz, referred to as "virtual
transponders". Each virtual transponder can be
remotely and independently switched on or off and its
gain adjusted. Channel filtering is achieved by using
305
https://ntrs.nasa.gov/search.jsp?R=19940018316 2020-06-16T15:59:40+00:00Z
SAW technology at an IF frequency of about 140
MHz.
manufacturers (FIAR-Italy and PESA-Spain) are
ready to produce MES's at competitive prices.
Two separate offset L-hand antennas are used for
transmit and receive, reusing the ITALSAT F-2
Ka-band elliptical reflectors ( projected aperture
diameter: 2m ) and dedicated L-band four "cup" feeds.
RHC and LHC circular polarisations are provided.
The typical coverage is shown in Figure 1. Assuming a
nominal voice channel EIRP of 19 dBW, 600
channels can be served simultaneously (including voice
activation factor).
3- PROPOSED MOBILE SYSTEMs
(see Refs. 1 and 2)
B- The Mobile Satellite Business Network (MSBN)
voice and data system
The present MSBN definition is the result of many
detailed stadies including market surveys, and
in-depth technical evaluation. The basic MSBN
concept represented in figure 3. shows that a fixed
user has direct access to his fleet of mobiles through
his own VSAT station installed on his premises and
pointed towards EMS. The VSAT station operates at
Ku-band and the mobile station at L-band. The
MSBN system uses quasi-synchronised CDMA access
techniques in both directions over the satellite
Two baseline systems are foreseen to be operated Via link.(see Ref 3). The choice of CDMA eases the
EMS: coordination with other satellite systems and is
A-The Low-data-rate PRODAT-2 system.
The PRODAT-2 system is the operationnal evolution of
the experimental PRODAT system which has been
successfully tested and demonstrated in Europe under
the responsibility of the European Space Agency
between mid-1987 and end 1992 (Ref l).The main
characteristics are very similar and the experience
gained during the trial phase together with the
evolution of the market has provided scope h_r
optimisation of the system. The system is an open,
centralised and modular system in which the fixed user
is connected to the Hub via the public net_vork, either
directly or via national or regional concentrators (see
Fig. 2). Link characteristics are given below:
-Store and forward
-Forward link:BPSK/TDM 1500 bit/s
-Return link: CDMA/OQPSK 600bit/s
-Adaptative block coding with ARQ
-Omnidirectionnal mobile antenna
-10 W RF power
PRODAT-2 main characteristics
-The basic communication functions are retained (Bi-
directional messaging, broadcast, request/reply and
polling). The public nefw0rk access to the iiub is
compatible with CCITT X400 recommendations in
addition to conventionnal fax/telex links. Several other
improvements have been hnplemented to cope , better
with users requirements. The PRODAT-2 system is
now ready for demonstration, for which a pre-series of
fully industrialised l_fES's (including a GPS card for
position determination) are awfilable. The two
particularly suited to the PMR (Private Mobile Radio)
concept where all the independant networks share a
common bandwidth resource without the need for
network coordination. The synchronisation of the
transmissions in both directions allows a greater
number of simultaneous users due to the drastic
reduction in the self-noise level. Also,the mobile
receiver acquisition is eased as a synchronisation
signal is continuously transmitted providing chip, code
and carrier synchronisation. In the basic
configuration, a pair of channels (codes) are allocated
to each business network in a star configuration, and
those channels are shared between the MES's under
the VSAT station control to handle up to about 125
trucks under average traffic conditions. It should be
noted that the system allows for a modular growth of
the conmmnication capabilities of the VSAT station
according to the growing needs of the transport
company. On the other hand, a VSAT station may be
shared by more than one company to reduce costs to
smaller companies. The link characteristics of MSBN
are given below:
-L-band mobile link
-Both link uses CDMA Quasi Synchronised
-QPSK at 867 KChip/s
-Voice at 6.4 Kbit/s
-Data at 2.4 Kbit/s
-Couvolutional and block coding
-Steered mobile antenna with 11 dB
gain (see refs. 4 and 5)
-10 W RF in transmit
MSBN main characteristics.
An experimental MSBN network is presently under
procurement by the Agency, and one YES
306
manufactured by SAIT (Belginm) and 14 MES's from
Fiar (Italy) and PESA (Spain) will be awlilable for
tests and demonstration by the end of 1993, using the
Marecs-A satellite.
4-SERVICES AND COMPETITION
Market surveys have revealed an urgent need in
Europe for specialised mobile services for the business
world, as distinct from public services offered by
Public Telecommunications Operators OPTO's). In the
international road-transport sector, for instance, the
needs are particularly pressing. Companies that
operate fleets of vehicles transporting goods across
Europe are very anxious to mait_tain instant
communications with their vehicles wherever they are.
With the opening of borders towards Ce,tral and
Eastern Europe, the satellite now appears as the only
practical way to provide mobile services to those
countries on a significant scale.
The poor telecommunication infrastructure of eastern
European countries also justifies the need for portable
terminals either for data and/or voice services to help
interactive businesses.
The actual mobile satellite services being introdoced
mainly by the PTO's in Europe are in,nars_,t's
standard-C and Eutelsat's Euteltracs. It is clear that
even if the trans-border communication services
offered are unique in Europe, their market
penetration rate is rather slow. The reasons for this
might be marketing, too high tarifs, inadequacy of
performances vis-a-vis user requirements or simply an
immature market.Both systems have a centralised
approach imposing the use of public networks to
connect the fixed user to the satellite system. The start
of these services ahead of EMS is not considered as a
handicap but rather a preparation of the market for
satellite services. Other competition will come from the
digital European cellular syste,n GSM which is
presently being introduced. The prices of mobile
terminals will certainly be lower than satellite
terminals due to the economies of scale, but the
flexibility and the service prices can easily be
challenged by a well-designed regional satellite system.
5 - ASSESSMENT OF POTENTIAL
SUBSCRIBERS
Awareness of the addressable market and definition of
the potential user profiles are fundamental il' _,
successful and profitable Land Mobile Satellite System
is to be implemented. A correct market seg,uentatiou
allows both the definition of
systems/products/services that suit the various user
requirements and the formulation of appropriate
marketing messages directed to the various segments,
aiming at differentiating the system/service/product
with respect to the various competitors. A study
performed by Telespazio for the Agency (see Ref. 6)
has evaluated the potential subscribers to EMS,
lhniting the analysis to the addressable potential
terrestrial user. The methodology persued included
the following steps:
(a) Assessment of present population of the
various user segments.
(b) Assessment of the future population
(1995 to 2005)
(c) Assessment of the potential users
(interested in mobile communication
services irrespective of the telecommunication
system, terrestrial or satellite).
(d) Assesment of the addressable users
(interested in LMSS communication
services).
(e) Assessment of the potential
subscribers for EMS specifically.
Estimates of potential users interested in mobile
commvuic_,tions services in Europe in 1995 and 2005
are given helow:
Y_r
Trucks
Railways
putehOer ¢osche4
Oooda v_e_
Professional
Travels
Dsm collection
&
MonRorlng AppI
m
Car Rental
[21
Rescue Users
Buses
/2j
Total
pmmtiJUNrs_looo)
1996 2006
2000 2687
69 76
962 1231
9000 9460
840 1023
34 46
tbd tbd
92 107
12997 14630
[_ On_ #dienuse=
307
The potential truck user include only those having
capacities greater than 3 tons. For the other user
groups, the entire future population of users has been
assumed (data regarding rescue users were not
available). It is worth noting that the end-user prices
assumed in the baseline forecast for the voice and data
service on EMS, have been determined on the basis of
the end-user prices of terrestrial celhdar systems with
the addition of a price for the satellite services. The
prices considered have been :
Terminal Prices ($) :
data :2200
voice :3500
End-User Prices ($)
Subscription charege :32
Data charge :0.285kbit
Voice charge : I S/rain.
Finally, the potential EMS subscribers have been
determined on the basis of service introduction time in
the market and competition from other LMSS system.
The figure below shows the growth curves for EMS
potential subscribers per basic service.
POTENTIAL SUBSCRIBERS OF EMS
_o_h F_le
180
llTtit6 1_ lm7 1_ 1_ 2000 2001 _X)2 2000 2004
• Yek_I+_)lll ÷ _ • PimQirql A Tolalt_ulb#cdb4prs
6-IMPLEMENTATION SCENARIO
The deployment of any telecommunication system
generally involves answering at least two major
questions:
-How will the system be hnplemented ?
-How will the system be operated ?
Key points of the physical hnplementation of any
LMSS are :
Space segment. Identification of its
characteristics and availability of the in-orbit
capacity and backup capacity.
Network deployment. Determination of various
phases to make the system operative.
In order to prepare the market,an interim PRODAT-2
low data rate service will be provided using Marecs-A
residual capacity. Then, the EMS payload embarked
on Italsat F-2 will be available in orbit by mid-1995.
Backup capacity will be provided by the LLM
(L-band Laud Mobile) payload to be embarked on
ARTEMIS, with a launch in 1996.
As far as network deployment is concerned, it
depends primarily on constraints dictated by the
technical and marketing/commercial analysis. In
particular, three main stages have been highlighted
with reference to technical and operational
considerations:
a) Test and demonstration of the
system. This is aimed at validating the
system from the both performance and
operational capability standpoints.
b) Pilot project (Pre-operational phase).
This is aimed at refining the system. In
addition, it is directed primarily at
promoting the system and validating it
from an operational viewpoint.
c) Operational Phase. This phase is
divided into two steps :
(lst) Private Network
(2nd) Public Network
The rationale for this choice is based on to both
market analysis and operational coRsiderations. A
reasonable date for Public Service introduction might
be 1996.
308
7 - CONCLUSIONS
The future European Mobile system making use of a
piggy-backed payload on a fixed communication
satellite has been presented and the various inherent
elements described. The design selected has been
carefuly matched to the requirements of the main
potential user groups that have been identified. The
chosen options allow problems related to the
coordination with other satellite systems to be
overcome from an interference point of view.
Moreover, the regional system described can compete
with other mobile teleconnnuuication services and can
be profitable for the system operator. Even if modest
in size, EMS also will open a new nmrket for the
European mobile and VSAT stations manufacturers
and the associated value-added service providers.
REFERENCES
Ill Results of Field Trials Conducted in
Europe with the PRODAT System
R. Rogard, A. Jongejans and
C.Loisy
ESA Journal - 1989 Vol 13
[2] LMSS: From Low Date Rate to
Voice Services.
R. Rogard
Proceeding 14th International
Communication Satellite Systems
Conference AIAA), Washington DC,
March 92
[3] First Satellite Communication Trials
using BLQS-CDMA.
M.L. de Mateo et al., also included in the
proceedings of the IMSC'93.
[41 Microstrip Monopulse Antenna for
Land Mobile Communications.
Q. Garcia et al., included in the
Proceedings of the IMSC'93.
[5] Small Stearable Land Mobile Antenna -
Final Report.
Estec contract: 8394/89/NLfPB
VTI" Technical Research Centre of Finland.
[6] System Architecture and Market
aspects of an European Land Mobile
Satellite system via EMS.
F. Ananusso, I. Mistretta.
Proceeding 14th AIAA conference -
March 92 Washington DC.
309
-I
-z
__ sJ_s
.... 3o'N
I -Z
" FIG 3 MSBN NETWORK
J I J a | Z _ 4
FIG.I: EMS TRANSMIT COVERAGE
%% % %
% •.
% •
•% • •
•%
FIG:2 PRODAT2 NETWORK CONCEPT
FIG 4: PRODAT MOBILE STATIONS
OLD (LEFT) AND NEW (RIGHT)
FIG 5: PROTOTYPE MOBILE ANTENNAS
DEVELOPPED FOR MSBN
310
Session 8
Propagation
Session Chair--Barry G. Evans, University of Surrey, England
Session Organizer--David Rogers, Communications Research Centre, Canada
Land Mobile Satellite Propagation Measurements in Japan Using
ETS-V Satellite
Noriaki Obara, Kenji Tanaka, Shin-ichi Yamamoto and Hiromitsu
Wakana, Communications Research Laboratory, Japan .................................. 313
Measurements on the Satellite-Mobile Channel at L- & S-Bands
H. Smith, J.G. Gardiner and S.K. Barton, University of
Bradford, England ............................................................................................ 319
K-Band Mobile Propagation Measurements Using ACTS
Julius Goldhirsh, Johns Hopkins University; and Wolfhard J. Vogel and
Geoffrey W. Torrence, University of Texas at Austin, U.S.A ......................... 325
Measurement of Multipath Delay Profile in Land Mobile
Satellite Channels
Tetsushi Ikegami, Yoshiya Arakaki and Hiromitsu Wakana,
Communications Research Laboratory; and Ryutaro Suzuki, National
Institute of Multimedia Education, Japan ........................................................ 331
A Study of Satellite Motion-Induced Multipath Phenomena
R.M. Allnutt, A. Dissanayake, C. Zaks and K.T. Lin, COMSAT
Laboratories, U.S.A .......................................................................................... 337
Electromagnetic Field Strength Prediction in an Urban Environment: A
Useful Tool for the Planning of LMSS
G.A.J. van Dooren, M.H,4.I. Herben and G. Brussaard, Eindhoven
University of Technology; and M. Sforza and J.P.V. Poiares Baptism,
European Space Technology and Research Centre, The Netherlands ............. 343
(continued)
Propagation Model for the Land Mobile Satellite Channel in
Urban Environments
M. Sforza, European Space Agency, The Netherlands; G. Di Bernardo,
Space Engineering, Italy; and R. Cioni, Ingegneria dei Sistemi, Italy ............ 349
A Prediction Model of Signal Degradation in LMSS for
Urban Areas
Takashi Matsudo, Kenichi Minamisono, Yoshio Karasawa and Takayasu
Shiokawa, KDD R&D Laboratories, Japan ..................................................... 355
Global Coverage Mobile Satellite Systems: System Availability versus
Channel Propagation Impairments
M. Sforza, S. Buonomo and J.P.V. Poiares Baptista, European Space
Agency, The Netherlands ................................................................................. 361
Systems Implications of L-Band Fade Data Statistics for LEO
Mobile Systems
Carrie L. Devieux, Motorola Satellite Communications, U.S.A ..................... 367


The European Mobile System (EMS)

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