esog220

esog220
EUTELSAT
S.A.
Systems Operations Guide
ESOG
Volume II
SATELLITE MULTI SERVICE (SMS)
HANDBOOK
Issue 2.0, 01-07-2004
Module
220
EUTELSATS.A.
SYSTEMS OPERATIONS GUIDE
ESOG
Module 220
SATELLITE MULTI SERVICE (SMS)
HANDBOOK
Issue 2.0
01-07-2004
1. INTRODUCTION................................................................................................................ 1
2. MANDATORY PRE-TRANSMISSION LINE UP TESTS (PTLU) ............................................. 3
2.1. Carrier EIRP, Centre Frequency, C/N and RF Bandwidth................................................ 3
2.2. HPA Output Spectrum of Tx Station at Nominal EIRP .................................................... 6
2.3. Additional tests for VSAT Hub/Terminal Stations ........................................................... 7
3. ADDITIONAL FULL LINE-UP TESTS (FLU)....................................................................... 8
3.1. C/N versus BER Performance at the Receive Earth Station............................................. 8
3.2. BER Continuity Test ................................................................................................... 9
3.3. Data Polarity Check...................................................................................................10
4. SMS SYSTEM OPERATION............................................................................................ 11
4.1. Reactivation of Digital Satellite Link following an Outage................................................11
4.2. Supervision of Operational Parameters.........................................................................12
4.3. Trouble Shooting........................................................................................................12
ANNEX A - Finding a Satellite................................................................................................. 13
ANNEX B - Earth Station Polarization Plane Adjustment....................................................... 14
ANNEX C - Spectrum Masks for SMS Carriers ..................................................................... 16
ANNEX D - Theory of C/N Spectrum Analyser Measurement ............................................... 17
ANNEX E - Relationship between C/N, (Co+No)/No and Eb/No............................................ 19
ANNEX F - Format for SMS PTLU/FLU Test Result Report.................................................. 22
FOREWORD
The Eutelsat S.A. Systems Operations Guide (ESOG) is published to provide all Eutelsat S.A.
space segment users with information that is necessary for successful operation of earth stations
within the Eutelsat S.A. satellite system.
The ESOG consists of 2 Volumes. They contain, in modularised form, all the necessary details,
which are considered important for the operations of earth stations.
Volume I concentrates on System Management and Policy aspects and is therefore primarily of
interest to personnel engaged in these matters.
Volume II is of direct concern to earth station staff who are directly involved in system operations,
i.e. the initial line-up of satellite links between earth stations and the commissioning of earth
stations for Eutelsat S.A. services. The modules that are contained in this Volume relate to the
services provided via Eutelsat S.A. satellites.
The ESOG can be obtained either by requesting a printed version to Eutelsat S.A. or in Acrobat
format from the Eutelsat S.A. Web:
http://www.eutelsat.com
Paris, 06-09-2004
i
OVERVIEW ESOG MODULES
VOLUME I
EUTELSAT S.A. SYSTEM MANAGEMENT AND POLICIES
Earth Station Standard ............................................................................................... Module 100
Earth Station Access and Approval Procedures........................................................ Module 110
Earth Station Type Approval....................................................................................... Module 120
Earth Station Verification Assistance (ESVA) ............................................................ Module 130
Operational Management, Control, Monitoring & Coordination.................................. Module 140
Services and Space Segment Reservation............................................................... Module 150
VOLUME II
EUTELSAT S.A. SYSTEMS OPERATIONS AND PROCEDURES
TV Handbook .............................................................................................................. Module 210
SMS Handbook........................................................................................................... Module 220
VSAT Handbook ......................................................................................................... Module 230
SKYPLEX Handbook (being prepared) ...................................................................... Module 240
DVB Television Handbook (being prepared) .............................................................. Module 250
ii
Page 1
1.
_______________
SATELLITE MULTI SERVICE HANDBOOK
INTRODUCTION
__________________________________________________________________
The purpose of this SMS Handbook is to outline the requirements for
commissioning digital SMS services via Eutelsat S.A. satellites and to
ensure that performance objectives are being met. This ESOG Module also
includes all necessary tests required to confirm that interactive VSAT
networks utilising the digital SMS capacity meet minimum requirements on
compatibility with overall system integrity.
The strategy for testing satisfies the different needs of the networks
(CLOSED and OPEN) that utilise the digital SMS capacity (including IDC):
Digital SMS Open Network: The open network is characterised by a set of
commonly adopted performance requirements and specifications in order to
guarantee compatibility between all user equipments. The tests relating to
the introduction of this type of network are all mandatory in order to ensure
compatibility with the network and to confirm that the common performance
objectives are being achieved.
Digital SMS Closed Network: The closed network may use a variety of
other performance characteristics not specified in the SMS System
Specification to allow users the maximum flexibility to meet any other
particular requirements. Therefore the mandatory tests, while identical to the
open network tests, are limited in number to ensuring that the parameters
which may potentially cause interference to other services are verified.
The balance of the tests are described as "recommended only" and, whilst
Eutelsat S.A. does not insist that these tests are completed (because there
are not any commonly adopted performance characteristics and
objectives), Eutelsat S.A. strongly recommends that they are effected prior
to the commencement of the initial service.
Following the above, and to ensure interference-free access to the space
segment while confirming the expected quality performance, a minimum set
of tests has been established that is applicable to any digital SMS user
either in the closed or open network environment. An overview of these tests
is given in Table 1.a below:
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ESOG
§
Test
PTLU
FLU
2.1
Carrier EIRP, centre frequency and RF bandwidth
X
X
2.2
HPA output spectrum of transmit stations
X
X
2.3
Additional tests for interactive VSAT terminals
X
X
3.1
C/N versus BER performance at the RX e/s
X
3.2
BER Continuity test
X
3.3
Data polarity check
X
Table 1.a: Carrier Line-Up Tests
As can be seen from the table, a Full Line-Up (FLU) consists of the
complete set of tests, while a Pre-Transmission Line-Up (PTLU) comprises
only a subset of the test programme.
In principle, the testing programme is identical for both networks. However,
in the case of the Open Network, all the tests are MANDATORY whereas in
the Closed Network only those which ensure the protection of other satellite
services are. This results in a utilisation of the two different groups of tests
in the following manner:
PTLU
FLU
Open Network:
mandatory
mandatory
Closed Network:
mandatory
recommended
The implementation of the balance of the tests in the closed network
environment are strongly recommended to ensure satisfactory operations.
However, as a minimum requirement to protect other users Eutelsat S.A.
must insist that the mandatory test procedures are completed satisfactory.
Upon satisfactory completion of the mandatory tests, the earth station
operator can assume that Authorisation to Operate as indicated in ESOG
Module 110 §3.2 has been granted for the earth station concerned.
Prior to accessing the satellite, any earth station must have obtained
Eutelsat S.A. Approval to Access the Space Segment in accordance with
ESOG Module 110.
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2.
MANDATORY PRE-TRANSMISSION
LINE-UP TESTS (PTLU)
_______________
__________________________________________________________________
The tests given in this chapter are mandatory for both the closed and open
network of the digital SMS services.
Some important preparatory issues for conducting successful testing are
presented below:
a. Test Plan, Test Schedule and Instructions: Prior to the commencement
of any satellite transmissions the Earth station/VSAT Operator shall have
received the detailed line-up test schedule containing all necessary
technical/operational parameters and other special instructions.
b. CSC Coordination Circuit: Prior to ANY satellite access the earth station
must establish communications to the Eutelsat S.A. CSC in Paris, as
detailed in the ESOG Module 140. The telex, facsimile and telephone
numbers are as indicated in the table of contact numbers attached to each
ESOG module.
c. Finding a Satellite: A simple procedure is given in Annex 1 to this Module
to assist SMS Earth Stations/VSAT Operators finding the desired Eutelsat
S.A. satellite.
d. Polarisation Alignment: A procedure to assist Earth Station/VSAT
Operators to align the earth station plane of polarization is described in
Annex 2 to this Module.
Test results shall be made available to Eutelsat S.A. by mail, fax, telex or
any other commercially available data system when requested. Annex 6 to
this Module includes the format for the test report.
2.1.
Carrier EIRP,
Bandwidth
Centre
Frequency,
C/N
and
RF
Purpose of Test:
To establish the nominal up-link and down-link EIRPs of
the carrier under test and to measure the centre
frequency, C/N and RF bandwidth.
Performance Objective:
The:
- Carrier Centre Frequency
- EIRP
- C/N
- RF Bandwidth
shall conform to the expected values as provided in the Line-Up Test
Plan/Schedule.
Test Equipment:
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• Spectrum Analyser
• RF Frequency Counter
• Camera/Plotter
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Test Procedure:
NOTE:
This test should be conducted under clear sky conditions at both the
transmit and receive earth stations. Polarisation plane alignment must have
been performed prior to any carrier activation (see procedure in Annex 2).
Step 1:
Access Coordination: The earth station under test shall ascertain by means
of a spectrum analyser that the satellite is free of any activated carrier in the
bandwidth and polarization which the earth station plans to illuminate. The
earth station under test must establish and maintain contact with the
Eutelsat S.A. CSC throughout the following steps.
Step 2:
Space Segment Access: Under the control of the Eutelsat S.A. CSC,
transmit the energy dispersed carrier at an EIRP of no more than
30 dBW into the allocated transponder at the assigned frequency.
Step 4:
Frequency Verification: The Eutelsat S.A. CSC will check and record the
correct downlink frequency and confirm compliance with the Transmission
Plan. If the Eutelsat S.A. CSC does not detect and confirm the carrier in the
assigned transponder and/or if the communications link between the earth
station under test and the CSC fails, the earth station under test shall:
+++++ immediately CEASE, transmissions +++++
The earth station under test shall again verify its set -up on:
- correct satellite acquisition
- polarization plane alignment
- transmit frequency
commencing with Step 1.
Step 5:
Transmit EIRP: Under the control of the Eutelsat S.A. CSC, the transmit
earth station gradually increases the EIRP of the assigned carrier.
Step 6:
EIRP and Crosspolar Isolation: The Eutelsat S.A. CSC will check and
record the corresponding downlink level and confirm that the crosspolar
component of the carrier under test is satisfactory and that no interference
to other services exists.
Step 7:
Space Segment Access Authorisation: Upon successful completion of
Steps 1-7 the transmitting earth station will be authorised by the Eutelsat
S.A. CSC to proceed with further line-up testing.
NOTE:
Removal of carriers: When transmit carriers are removed the Eutelsat S.A.
CSC must be immediately advised and any carrier re-activation is subject to
authorisation by the Eutelsat S.A. CSC. Carriers must be removed
immediately if required to do so by the Eutelsat S.A. CSC.
Step 8:
Measurement of Carrier-to-Noise Power Density Ratio (Co/No). At the
receive earth station:
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a)
b)
c)
d)
e)
Step 9:
Display the carrier spectrum from the receive IF on the spectrum
analyser.
Adjust the sweep bandwidth to allow the carrier width to be 20 to 30
percent of the horizontal display.
Ensure that the resolution filter bandwidth in use is less than 20% of
the signal bandwidth. For example, a 10 kHz filter would be suitable for
an 70 kHz carrier.
Adjust the instrument's step attenuator to place the peak of the carrier
on some convenient horizontal reference line with the vertical scale
set to 1 or 2 dB per division.
Use as much video filtering as practical to limit the uncertainty in the
average level. Note the attenuator setting.
Measurement of Noise Power
a) Decrease the spectrum analyser attenuator setting to move the signal
up.
b) Continue until the noise level is brought up to the same horizontal
reference mark as was used for the carrier.
c) Note the attenuator setting at this point.
Step 10:
Calculation of Co/No: Take the difference in the attenuator settings noted in
Steps 8 and 9 This is the (Co + No)/No ratio of the spectral densities.
Correct the measured value (Co + No)/No to Co/No using the Table in
Annex 4.
Step 11:
If Step 10 above does not provide the expected results, the Eutelsat S.A.
CSC will then decide whether or not the Transmit stations EIRP requires
adjustment to obtain the expected C/N.
Step12:
Upon successful completion of Step 11, the transmit earth station shall
record the analyser display reading and the corresponding earth station
EIRP. This level should be maintained from now on unless instructed by the
Eutelsat S.A. CSC to change.
Step13:
Without radiating the unmodulated carrier to the satellite the transmit earth
station will measure its own carriers centre frequency. Record the result for
the test report.
Step 14:
The transmit earth station should now re-radiate the modulated carrier to the
satellite. The Eutelsat S.A. CSC will then measure the bandwidth occupied
by the carrier within the 10 dB points of its spectrum.
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2.2.
HPA Output Spectrum of T x Station at Nominal EIRP
Purpose of Test:
To characterise the transmit spectrum at the HPA output
after all filtering and to ensure it meets the performance
objectives before other tests are conducted. The
carrier's spectrum requirements are to be met when the
carrier is transmitted at its nominal EIRP level as
established during the previous test.
Performance Objective:
The actual transmitted RF spectrum shall be within the
limits of the mask given in Figures A3. of Annex 3. The
transmission rate (R) used in the mask calculation shall be
the satellite links transmission rate (i.e. after FEC coding).
Test Equipment:
• Spectrum Analyser
• X-Y Plotter or Camera
Test Procedure:
NOTE:
The receive earth station is not required to participate in this test.
Step 1:
At the transmit earth station, connect the modulator IF output to the input of
the spectrum analyser.
Step 2:
Adjust the spectrum analyser setting to a span of approximately 3 times the
allocated bandwidth and display the signal spectrum at the centre
frequency. Use a resolution filter bandwidth less than the signal bandwidth.
The instrument should be set to an average responding display with enough
video filtering to reduce the noise to less than 0.25 dB p-p. The vertical scale
should be set to 10 dB per division.
Step 3:
Measure the actual signal bandwidth at the -10 dB points and record the
result, photograph or plot the spectrum.
Step 4:
Disconnect the spectrum analyser and reconnect the modulator output to
the transmit system.
Step 5:
Connect the spectrum analyser to the HPA output test point at RF, after all
filtering.
Step 6:
Set up the spectrum analyser at the carrier frequency as described in Step
2.
Step 7:
Compare the spectrum with the mask in Figure A3 of Annex 3. Measure the
level at the appropriate points, e.g.: +0.5MABW (maximum allocated
bandwidth) in the case of closed network carriers.
Step 8:
Record the results for inclusion into the test report telex and forward the
hard copy separately to Eutelsat S.A. If this test is satisfactorily, continue
with the next test.
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2.3.
NOTE:
Additional tests for VSAT Hub/Terminal Stations
Prior the proceeding with the following tests the Hub Station must have
completed the PTLU tests in the previous paragraphs 2.1 - 2.2. The
following tests apply to the initial setting up of interactive VSAT networks.
Purpose of Test:
To ensure that transmitting VSAT terminals cease
transmission at any time, WHEN required for operational
reasons.
Performance Objective:
When the Hub outbound carrier is removed, Transmitting
VSATs must automatically respond by ceasing their
transmissions.
Test Coordination:
Immediately prior to the commencement of and
throughout the tests the HUB station must establish and
maintain direct contact with the Eutelsat S.A. CSC.
Test Procedures:
Step 1
Perform a system start up with at least one remote VSAT on each inbound
carrier.
Step 2
At the Eutelsat S.A. CSC, confirm adherence to the agreed Transmission
Plan for the system under test.
Step 3
Upon request by the Eutelsat S.A. CSC at the HUB station cease
transmission of the out bound carrier.
Step 4
At the Eutelsat S.A. CSC, confirm the remote VSAT terminal ceases to
transmit so that no inbound carrier is being radiated.
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3.
_______________
ADDITIONAL FULL LINE-UP TESTS (FLU)
__________________________________________________________________
The tests presented in this chapter form, together with the (mandatory)
PTLU tests given in Chapter 2, the Full Transmission Line-up. These
additional tests are mandatory for the Open Network and recommended for
the Closed Networks.
Upon completion, the test results shall be made available to
Eutelsat S.A. by mail, fax, telex or any other commercially available data
system when requested. Annex 6 to this Module includes the format for the
test report.
3.1.
C/N versus BER Performance at the Receive Earth
Station
Purpose of Test: To record the Co/No and BER performance curve at the receiving
earth station by varying the transmit up-link EIRP, in order to
reduce the Co/No from nominal in defined steps until sufficient
reliable non-zero BER data points are measured to characterise
the carrier performance taking into account actual transmission
parameters, actual earth station G/T and the demodulation
threshold performance.
Test Equipment: •
•
Spectrum Analyser
BER Test Set
Test Procedure:
NOTE:
This test should only be conducted under clear sky conditions.
Step 1:
The carrier under test shall be radiated with the nominal EIRP as
established during Test No. 2.1, with the Eutelsat S.A. CSC and/or the
receive station confirming the corresponding down-link level and Co/No,
before proceeding with the test.
Step 2:
At the transmit earth station, connect the BER generator to the modulator
input or, if FEC is used, to the FEC encoder input. At the receive earth
station, connect the BER receiver to the demodulator output or to the FEC
decoder output, if FEC is used. At both earth stations, set the pattern mode
switch on the BER test set to a Pseudo Random Bit Sequence (PRBS) for
a pattern conforming to the bit rate of the carrier under test:
e.g. 211 - 1 for 64 kbit/s or 215 - 1 for 2 MBit/s
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Step 3:
At the transmit and receive earth station set, the BER test set according to
the manufacturers instructions. The receive earth station records the
number of errors over the test period as given below and computes the
BER.
Customers bit rate
Approximate Measurement Time
64 kbit/s
60 minutes
128 kbit/s
30 minutes
or 2500 errors
256 kbit/s
20 minutes
whichever occurs
1920 kbit/s
20 minutes
first
Step 4:
At the transmit earth station, decrease the EIRP in defined steps (e.g.
nominal EIRP -3 dB; -4 dB etc.), and at the receive station measure the
BER as prescribed in Step 3. Repeat this process until the receive earth
stations modem continuously loses synchronisation. Record for each step,
the Co/No, the corresponding up-link EIRP, test period, BER and weather
conditions for inclusion in the test report.
Step 5:
Increase the transmit earth station's EIRP in increments of 0.3 to 0.5 dB
until the receive modem regains sync.
Step 6:
Measure and record the Co/No up-link EIRP and BER.
Step 7:
Repeat Step 5 through 6 until at least three non-zero BER readings are
obtained. Record the BER, EIRP and Co/No. Repeat Step 5 and 6 until a
BER reading better than 10-6 is obtained.
Step 8:
Upon completion of Step 7 above, the transmit earth station shall restore the
nominal EIRP as established under Test 2.1.
3.2.
BER Continuity Test
Purpose of Test: To validate the BER performance of the satellite radio link between
the transmit and the receive earth stations over a 24 hour test
period. The test will be conducted under nominal link conditions.
Test Equipment: BER Test Set
Test Procedure:
Step 1:
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The carrier under test should be radiated with the nominal EIRP and
corresponding (Co + No)/No as established during Test 2.1.
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Step 2:
At the transmit earth station, connect the BER generator to the modulator
input or, if FEC is used, to the FEC encoder input. At the receive earth
station, connect the BER receiver to the demodulator output or to the FEC
decoder output, if FEC is used. At both earth stations, set the pattern mode
switch on the BER test set to a PSEUDO random bit sequence (PRBS) for
a pattern conforming to the bit rate of the carrier under test:
e.g. 211 - 1 for 64 kbit/s or 215 - 1 for 2 MBit/s
Step 3:
3.3.
At the transmit and receive earth station, set the BER test set according to
the manufacturers instructions and record, at the receive earth station, the
number of errors over convenient test intervals throughout the next 24
hours, and compute the BER.
Data Polarity Check
Purpose of Test: To verify the correct polarity transmission of data signals between
the transmit and receive earth station.
Test Equipment: BER Test Set
Test Procedure:
Step 1:
Connect the BER test set to the modem at both the transmit and the receive
earth station.
Step 2:
At the transmit earth station, an "all zeros" data pattern will be transmitted.
Step 3:
If an "all zeros" data pattern is received, the receive earth station's polarity is
correct, otherwise a polarity inversion has occurred.
Step 4:
Record whether or not the polarity is correct on the test report.
NOTE:
Upon completion of this test, forward final test report with all results of the
Full Line-Up (FLU) to Eutelsat S.A. For the format of the test report, refer to
Annex 6 of this ESOG Module.
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4.
SMS SYSTEM OPERATION
_______________
__________________________________________________________________
Digital satellite links in the Eutelsat S.A. SCPC/SMS System are operated on
a multiple access basis through common satellite transponders. Any deviation
from the parameters initially established can cause degradation of some or all
of the digital satellite links being operated through a particular transponder.
For this reason, great care should be exercised to keep all system parameters
within the specified limits to ensure that degradation of service due to mutual
interference does not occur.
Day-to-day operations concerning network maintenance, including such
matters as EIRP adjustments and RF network carriers transmission
scheduling, will be controlled by the Eutelsat S.A. CSC.
The Network Control Centres (NCCs) shall address all communications, on
operation of its earth stations under their responsibilities to the
Eutelsat S.A. CSC.
Any temporary deviation from the established parameters considered
necessary for operational, maintenance or other reasons requires the prior
approval of the Eutelsat S.A. CSC.
Interruption of satellite communication links should be strictly limited to
emergencies and routine maintenance causing interruptions should be
avoided.
Normal in-station, off-line, routine maintenance of earth station equipment
together with checks of operating links should be sufficient to maintain the
system in proper operating condition.
Although earth station operators are fully aware of the importance of
maintaining their earth stations in optimum operational condition,
Eutelsat S.A. stresses the importance of basic precautions at all earth stations
and to the system as a whole.
4.1.
Reactivation of Digital Satellite Link following an
Outage
Following an outage of a digital satellite radio link where the transmit carrier
has failed or has been removed, reactivation shall take place in accordance
with the following procedure:
a)
b)
c)
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Prior to reactivation, the NCC of the transmitting earth station advises
the Eutelsat S.A. CSC of the carrier(s) to be reactivated.
The reactivated carrier will be measured by the Eutelsat S.A. CSC or
by alternative monitoring facilities in frequency and power.
Following the satisfactory reactivation of the carrier, the NCCs of the
receiving earth station(s) will advise the Eutelsat S.A. CSC and NCC
of the transmitting earth station that the link is back in service.
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4.2.
Supervision of Operational Parameters
The most important parameters to supervise with utmost precaution are:
a)
b)
c)
d)
4.3.
Transmit EIRP: Carrier must never be activated without direct control
of the Eutelsat S.A. CSC and they should be maintained at the power
within the specified limits.
Transmit Frequency: The centre frequency of any carrier may not
differ from its specified value.
Antenna Movement: Transmit carriers should always have their power
removed before moving an antenna away from the satellite. In order to
avoid variations in down-link EIRP and in crosspolar isolation,
particular care should be exercised to keep the tracking accuracy of
the antenna within appropriate limits.
Transmit Polarisation Isolation: Correct polarisation plane alignment
must be maintained at all times.
Trouble Shooting
The Eutelsat S.A. CSC can assist earth station in locating problems either
within the satellite link or the earth station.
In the case where satellite links are interfered with by other RF emissions
earth station operators should refer to ESOG Module 140, §9: "Interference
Reporting".
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Annex A _______________
Finding a Satellite
__________________________________________________________________
Step 1:
Check azimuth, elevation and polarisation angle calculations.
Step 2:
Check magnetic variation figure for earth station site to give correct
magnetic azimuth bearing.
Step 3:
Accurately set antenna pointing and feed polarisation offset.
Step 4:
Verify the frequency of the on-board satellite beacon or another existing or
temporary RF carrier. Calculate the down converted frequency accurately
that you will be viewing on the spectrum analyser. Remember that many
LNB's (Low Noise Block down-converters) have fairly inaccurate DRO local
oscillators (+/- 2 MHz is common) and this must be taken into account
when setting the spectrum analyser span/division and resolution bandwidth.
Step 5:
If using the on-board satellite beacon, its level is very low and it linearly
polarised. Hence, the position of the feed will affect the beacon level. Also,
ensure that the spectrum analysers sweep bandwidth and resolution
bandwidth is optimized or the beacon will be impossible to see.
NOTE:
The on-board beacon is visible from any point within Eutelsat S.A. satellite
beam coverage.
Step 6:
Once all these values are determined and the antenna is pre-pointed, begin
a slow antenna sweep in azimuth each side of the calculated azimuth and
repeat in small (0.5°) elevation increments. Carefully peak antenna pointing
once the beacon is detected.
Step 7:
If a temporary RF carrier is being used, it can also be used to peak the
polariser. Because of the response of the feed, it is better to "null out" the
marker and then rotate back 90° trying to peak directly. If a temporary
marker had been used, it is valuable to use the spectrum analyser to find
the satellites on-board beacon to double-check, that you are pointed to the
desired Eutelsat S.A. satellite.
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Annex B _______________
Earth Station Polarization Plane
Adjustment
__________________________________________________________________
Upon acquisition of the desired satellite (see Annex 1), the following
procedure should be employed to optimise the earth station's polarisation
plane:
Step 1:
Connect the spectrum analyser to the X-polarisation output port of the
antenna feed system.
Step 2:
Adjust the spectrum analyser to receive the satellites beacon frequency.
Step 3:
Gauge carefully the antenna in azimuth (AZ) and elevation (EL) to achieve
maximum satellite beacon level on the spectrum analysers screen.
Step 4:
When the satellite beacon is shown on the spectrum analysers screen
ensure that the instruments sweep bandwidth and resolution bandwidth is
optimised.
Step 5:
Gauge carefully the polariser (or feed) in clockwise and counter clockwise
direction until maximum receive beacon level is optimised. Mark the antenna
and polariser (or feed) positions and note the beacon level value.
NOTE:
Observe the moderate changes in beacon receive level while gauging the
antenna and polariser (or feed) around the maximum beacon level readings.
Step 6:
Remove the spectrum analyser from the X-polarisation port and connect the
instrument to the Y-polarisation output port of the feed system without
changing the previous frequency, sweep bandwidth and resolution
bandwidth settings.
Step 7:
Re-adjust the instruments sweep bandwidth and resolution bandwidth until
the cross-polar component of the beacon level can be clearly measured on
the spectrum analysers screen.
NOTE:
Observe the very low receive level of the satellite beacon which is to be
used for gauging the polariser (or feed) to achieve minimum overall crosspolarisation discrimination.
Step 8:
Gauge very carefully the polariser (or feed) in clockwise and counter
clockwise direction until minimum beacon level has been reached. Mark
position and this beacon level value.
NOTE:
Observe the very fast changes in receive beacon level when gauging very
slowly the polariser (or feed), in counter clockwise direction, through the
minimum beacon level reading on the spectrum analyser screen.
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Feed system cross-polarisation optimisation (also called "Nulling") has been
achieved when the polariser (or feed) has been adjusted and set to
minimum satellite beacon receive level in Y-polarisation.
Minimum receive beacon level in Y-polarisation should normally correspond
to maximum receive beacon level in X-polarisation at the same setting of the
polariser (or feed).
Step 9:
Compare the polariser (or feed) setting in X-polarisation with the polariser
setting achieved in Y-polarisation (Step 8). It should be the same.
Step 10:
Polarisation discrimination has now been optimised on-site.
N.B:
Should the Beacon Signal not be available then any other signal radiated
from the satellite may be utilise for the above purpose.
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Annex C _______________
SATELLITE MULTI SERVICE HANDBOOK
Spectrum Masks for SMS Carriers
__________________________________________________________________
Figure A1: Mask for SMS Services
RL(dB)
fc
Maximum Allocated
Bandwidth (MABW)
For the SMS Network, the mask is referenced to the Maximum Allocated
Bandwidth.
Normally the Maximum Allocated Bandwidth is defined in order to protect
two neighbouring carriers of any type. If however two "similar" carriers are
put adjacent to each other, values lower than usual might be allocated.
The Maximum Allocated Bandwidth is determined from the Transmit Symbol
Rate (TSR), usually by applying a Filter Roll-off Coefficient of 40 %. The
Transmit Symbol Rate in its turn depends on the Transmission Rate (R),
and the modulation applied.
The value for RL (Relative Level) depends on the TSR and on the allocated
Reference Carrier EIRPo (i.e. the EIRP allocated for a transmit earth station
located in the satellite reference contour of -0.5 dB/K for EUTELSAT II and
of 0 dB/K for Hot Bird and W satellites); both values, TSR and EIRPo are
stated in the Eutelsat S.A. Transmission Plans.
The formulae to calculate RL are:
RL = EIRPo - 10 log10 (TSR) - 36 dB for: TSR < 4 Msymb/s
RL = EIRPo - 42 dB
for: 4 Msymb/s < TSR < 12.5 Msymb/s
RL = EIRPo - 10 log10 (TSR) - 31 dB for: TSR >12.5 Msymb/s
with TSR expressed in Msymb/s.
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Annex D _______________
Theory of C/N
Measurement
Spectrum
Analyser
__________________________________________________________________
A convenient method of measuring carrier-to-noise density ratio (C/No)
uses a spectrum analyser. Good results can be obtained if care is taken in
operation of the instrument. The spectrum analyser measurement can be
converted to a carrier-to-noise density ratio (C/No) by the method described
below. A modulated QPSK transmission that uses a scrambler has a
spectral density (Co) at its centre frequency that is a function of the total
carrier power and the transmission rate. This can be expressed as :
where :
Co =
C - 10 log (R/2)
dBW/Hz
Co =
C =
R =
Spectral Density
Carrier Power
Transmission Rate
dBW/Hz
dBW
bit/s
(1)
An alternate form of the same expression is:
Co =
C + 3 - 10 log (R)
dBW/Hz
(2)
A spectrum analyser using a resolution bandwidth that is less than the
signal bandwidth will measure the carrier power spectral density. When a
PSK signal is measured in the presence of noise, the spectrum analyser
will display the ratio of the carrier spectral density and the noise spectral
density. Since the ratio is of two spectral densities, the value will be
independent of the actual noise bandwidth of the spectrum analyser
resolution filter. Therefore, it is not necessary to know either the noise
bandwidth or the log converter RMS correction factor to correctly measure
the ratio of two spectral densities.
The ratio of the carrier spectral density and the noise spectral density
(which the spectrum analyser measures) is actually a (Co+No)/No ratio.
The correction factors given in the table on the next page must be used to
give the actual Co/No ratio.
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(Co + No)
No
(dB)
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
11.0
12.0
13.0
14.0
15.0
16.0
17.0
18.0
19.0
20.0
Correction
Factor
Co
No
(dB)
(dB)
- 3.02
- 2.57
- 2.20
- 1.90
- 1.65
- 1.44
- 1.26
- 1.10
- 0.97
- 0.85
- 0.75
- 0.66
- 0.58
- 0.52
- 0.46
- 0.36
- 0.28
- 0.22
- 0.18
- 0.14
- 0.11
- 0.09
- 0.07
- 0.06
- 0.04
0.0
0.9
1.8
2.6
3.3
4.1
4.7
5.4
6.0
6.6
7.2
7.8
8.4
9.0
9.5
10.6
11.7
12.8
13.8
14.9
15.9
16.9
17.9
18.9
20.0
Co/No Conversion Table
The Co/No ratio thus obtained can easily be converted into the common units
used to measure signal-to-noise ratios through the following derivation :
Co
C
C/No
C/No
C/No
ESOG Volume II
=
=
=
=
=
Module 220
C + 3 - 10 log (R)
Co - 3 + 10 log (R)
C - No
Co - 3 + 10 log (R) - No
Co/No - 3 + 10 log (R)
dBW/Hz
dBW
dB/Hz
dB/Hz
dB/Hz
(2)
(3)
(4)
(5)
(6)
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Annex E _______________
SATELLITE MULTI SERVICE HANDBOOK
Relationship Between C/N, (Co+No)/No
and Eb/No
__________________________________________________________________
AE.1 C/No: Carrier-To-Noise Spectral Density Ratio
The carrier-to-noise spectral density ratio is an "artificial" measure of signalto-noise ratio. It is artificial in the sense that it implies that it is possible to
measure noise power in a filter having a noise bandwidth of 1 Hertz. Real
measurements made with actual filters of wider bandwidth must be
converted to express the C/No. The carrier-to-noise spectral density is a
useful measure, as it expresses satellite link performance in terms that are
independent of the measuring method. The "artificial" measure can be
related to a realisable measurement as:
C/No = C/N + 10 log (B)
dB/Hz
(1)
Where: C/N is the measured ratio using a filter of bandwidth B Hertz.
It has been assumed that the QPSK signal will occupy a bandwidth equal to
0.6R, where R is the actual transmission rate. This bandwidth, (0.6R), is
used to calculate the signal's C/N:
C/No = C/N + 10 log (0.6R)
C/N = C/No - 10 log (0.6 R)
C/N = C/No + 2.2 - 10 log (R)
dB/Hz
dB
dB
(2)
(3)
(4)
This relation for C/N is only valid for a filter bandwidth equal to the occupied
bandwidth of the QPSK signal. It is important to use the actual transmission
rate for R.
AE.2 Eb/No: Energy Per Bit/Noise Power Per Hertz
The Eb/No is commonly used to evaluate the performance of digital
modems. It is defined by the general formula as:
where:
ESOG Volume II
Eb/No = C/No - 10 log (data rate)
dB
Eb = Energy Per Bit
(referred to the data rate)
No = Noise Spectral Density
C = Carrier Power
dBW/Hz
dBW/Hz
dBW
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The data rate in bits per second could be the symbol rate, transmission
rate, composite rate or information rate. The Eb/No is then referred to the
chosen data rate, and it is important to bear that in mind when using the
Eb/No in any calculations.
Just as a C/N measurement has no real significance without a definition of
the measurement bandwidth, Eb/No must be carefully specified in terms of
the data rate associated with the value. Modems having built-in codecs are
typically specified by the manufacturer in terms of the uncoded or input
composite data rate Eb/No.
The composite data rate is the sum of the information rate and the overhead
(OH) bit rate and does not include any bits for forward error correction
(FEC).
The composite rate Eb/No is defined as follows:
Ebc /No = C/No - 10 log (IR + OH)
where :
IR
OH
(6)
= information rate (bits/sec)
= overhead (bits/sec)
When FEC is used, the "Transmission Rate (R)" is generated by the
addition of forward error correction (FEC) information to the uncoded
composite rate . The transmission rate is the product of the composite rate
and the inverse of the FEC coding rate.
The transmission rate Eb/No is defined as follows:
Ebt/No = C/No - 10 log (R)
where:
(7)
R = transmission ratebits/sec
Thus, the transmission rate of a Rate 3/4 system will be 1.333 (i.e. 4/3)
times the composite rate and the transmission rate Eb/No will be 1.25 dB
(10 log 4/3) less than the composite rate Eb/No, for Rate 3/4 FEC.
The transmission rate of a Rate 1/2 system will be 2 times the composite
rate. Therefore, the transmission rate Eb/No will be 3 dB (10 log 2) less
than the composite rate Eb/No for Rate 1/2 FEC.
The transmission rate Eb/No has particular relevance to spectrum analyser
Co/No measurements. For QPSK, the transmission rate Eb/No is 3 dB
less than the spectrum analysers Co/No. The relationship between C/No,
Co/No, Eb/No and C/N is shown in the following.
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AE.3 Co/No, C/No, Eb/No and C/N
C/No
Co
C
C - No
=
=
=
=
C - No
C + 3 - 10 log (R)
Co - 3 + 10 log (R)
Co - 3 + 10 log (R) - No
dB/Hz
dBW/Hz
dBW
dB/Hz
(8)
(8a)
(9)
(10)
C/No
= Co/No - 3 + 10 log (R)
dB/Hz
(11)
Ebt/No1 = C/No - 10 log (R)
dB
(7)
Ebt/No1 = C/No - 3 + 10 log (R) - 10 log (R)
dB
(12)
Ebt/No1 = C/No - 3
dB
(13)
Ebc /No2 = C/No - 1.75
(for rate 3/4 FEC)
dB
(14)
Ebc /No2 = C/No
(for rate 1/2 FEC)
dB
(15)
finally, for the C/N in the QPSK occupied bandwidth:
C/N
C/N
= C/No + 2.2 - 10 log (R)
= Co/No - 3 + 10 log (R) + 2.2 -10 log (R)
dB
dB
(4)
(16)
C/N
= Co/No - 0.8
dB
(17)
To reiterate, Co/No is the ratio of carrier to noise spectral density obtained from
the spectrum analyser measurement after correction for the (Co + No)/No
difference. In all cases, R is the actual transmission rate.
Co/No
Co/No
Co/No
Co/No
Co/No
=
=
=
=
=
C/No + 3 - 10 log (R)
Ebt/No + 3
Ebc /No + 1.75
for Rate 3/4 FEC
Ebc /No
for Rate 1/2 FEC
C/N + 0.8
dB
dB
dB
dB
dB
(11)
(13)
(14)
(15)
(18)
NOTE 1: Ebt /No relates to the transmission rate R.
NOTE 2: Ebc /No relates to the composite data rate.
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Annex F -
Format for SMS PTLU/FLU Test Result
Report
_______________
__________________________________________________________________
The next pages give the format of the Test Result Report, to be sent to the
CSC upon completion of the line-up testing.
Facsimile and telex addresses of the CSC are given in the list of
Operational Contact Points in the back of every ESOG Module.
To
:
Eutelsat S.A. CSC, Paris
From
:
.................................................................
(originating earth station)
Copy
:
.................................................................
(participating earth station(s))
Eutelsat REF
:
.................................................................
(reference of Eutelsat S.A. Test Plan)
Reference
:
.................................................................
(reference of reporting entity)
Subject
:
.................................................................
(subject of Eutelsat S.A. Test Plan)
A.
General Information
A.1
Earth station under test
: ........................................................................
(Eutelsat S.A. e/s code)
A.2
Date and time (utc) of test
: ........................................................................
........................................................................
(actual period of time when testing was conducted)
A.3
A.4
Prevailing weather conditions
at earth station under test:
Test conducted by
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: ........................................................................
: ........................................................................
(name of test manager)
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B.
Transmit Link Results
B.1
Test 2.1 Carrier transmit frequency and EIRP
B.1.1
RF carrier frequency
: ...........................
MHz
B.1.2
Carrier transmit power reading
(only applicable for single carrier)
: ...........................
dBm
B.1.3
Corresponding EIRP
: ...........................
dBw
B.2
Test 2.2 HPA Output Spectrum
B.2.1
10 dB bandwidth at IF
: ...........................
MHz
B.2.2
10 dB bandwidth at RF
: ...........................
MHz
B.2.3
Spectral level at + 0.35 R
: ...........................
dBC
B.2.4
Spectral level at - 0.35 R
: ...........................
dBC
B.2.5
Spectral level at + 0.5 R or MABW
: ...........................
dBC
B.2.6
Spectral level at - 0.5 R or MABW
: ...........................
dBC
B.2.7
HPA output meets mask
: Yes / No
B.2.8
Spectrum plot to be enclosed
: Yes / No
B.3
Test 2.3 Additional Test for Interactive VSAT Systems
B.3.1
VSAT System (EUTELSAT Network Code)
: .......................................
B.3.2
Date and Time (UTC) of test
: .......................................
B.3.3
Compliance with Performance Objective
: Yes / No
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C.
Receive Link Results
C.1
Test 3.1 Carrier-to-Noise Ratio
C.1.1
(Co + No)/No reading
: ...........................
dB
C.1.2
Calculated Co + No
: ...........................
dB
C.1.3
C/N
: ...........................
dB
C.1.4
Carrier down link level at CSC
: ...........................
dBW
C.1.5
Test 3.2 (Co/No)/No versus BER Performance
EIRP at TX Earth
Station
(Co + No)/No at Rx
Earth Station
(dBW)
(dBW)
BER
Nominal EIRP
- 3 dB
- 4 dB
- 5 dB
- 6 dB
- n dB (Sync Loss)
C.1.6
Spectrum Analyser Type
Resolution Bandwidth
ESOG Volume II
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: ...........................
kHz
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D.
Nominal Link Performance
D.1
Test 3.2 BER Continuity Test
D.1.1
Start of Test (Date, Time UTC)
: ..............................................
D.1.2
End of Test (Date, Time UTC)
: ..............................................
D.1.3
BER
: ..............................................
D.1.4
Conclusion
: ..............................................
D.2
Test 3.3 Compatibility Test
D.2.1
Data polarity correct
: Yes / No
D.3
Type of modem at earth station under test
(Manufacturer, Type)
: ..............................................
..............................................
D.4
Remarks
: ..............................................
........................................................................................................................................
........................................................................................................................................
........................................................................................................................................
ESOG Volume II
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EUTELSAT S.A. OPERATIONS CONTACT POINTS
Eutelsat S.A. CSC
e-mail: [email protected]
Voice:
Fax:
+33-1-45.57.06.66
+33-1-45.75.07.07
Systems Operations Division
Voice:
Fax:
+33-1-53.98.48.12
+33-1-53.98.37.41
Earth Station Approval
and Line-up Office
e-mail: [email protected]
Voice:
+33-1-53.98.39.25
+33-1-53.98.46.13
ESVA
Voice:
+33-1-53.98.48.25
+33-1-53.98.49.76
Voice:
Fax:
+33-1-53.98.48.28
+33-1-53.98.30.00
Voice:
+33-1-53.98.47.48
+33-1-53.98.47.45
+33-1-53.98.39.48
+33-1-53.98.37.37
Operational Planning Division
e-mail (SMS Section):
[email protected]
e-mail (LT Section):
[email protected]
Eutelsat S.A. Booking Office
e-mail: [email protected]
Fax:
Mailing Address
Eutelsat S.A. Web
Eutelsat S.A.
70, rue Balard
F-75502 PARIS Cedex 15
FRANCE
http://www.eutelsat.com
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