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TECHNICAL REPORT
Satellite Earth Stations and Systems (SES);
Technical analysis for the Radio Frequency, Modulation and
Coding for Telemetry Command and Ranging (TCR)
of Communications Satellites
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2 ETSI TR 103 956 V1.1.1 (2018-12)
Reference
DTR/SES-00428
Keywords
coding, modulation, satellite, telemetry
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3 ETSI TR 103 956 V1.1.1 (2018-12)
Contents
Intellectual Property Rights . 4
Foreword . 4
Modal verbs terminology . 4
Executive summary . 4
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definition of terms and abbreviations . 7
3.1 Terms . 7
3.2 Abbreviations . 10
4 Frequency Planning and Operational Scenarios . 11
4.1 Frequency Planning . 11
4.1.1 Frequency Bands . 11
4.1.2 Frequency Flexibility . 11
4.2 Hosted Payloads . 12
4.3 Operation during Launch and Early Orbit . 12
4.4 Operation in Other Orbits . 12
5 Spread Spectrum Modulation . 13
5.1 Extension of PN Code Family . 13
5.2 Symbol Rate . 15
5.3 New MTC3 Mode . 15
5.4 In-phase to Quadrature Power Ratio . 17
5.5 Out-of-Band Emission and Discrete Spurious . 18
5.6 Physical Layer Operations Procedure. 18
6 Non-spread Modulation . 19
6.1 Uplink Phase Modulation . 19
6.2 Miscellaneous . 19
7 Coding and Interleaving . 19
7.1 General . 19
7.2 Uplink . 20
7.2.1 Forward Error Correction . 20
7.2.2 Pseudo-randomization . 21
7.3 Downlink . 22
7.3.1 Forward Error Correction . 22
7.3.2 Pseudo-randomization . 23
8 Conclusion . 23
Annex A: Generation and Validation of the Extended PN Code Library . 24
A.1 Dual Channel Gold Codes . 24
Annex B: Validation of Doppler and Doppler Rate requirements . 27
B.1 Summary of Previous Work . 27
B.2 Additional Analysis . 27
B.3 Conclusion . 29
Annex C: Cryptographic Pseudo-random Codes . 30
History . 32
ETSI
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4 ETSI TR 103 956 V1.1.1 (2018-12)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This Technical Report (TR) has been produced by ETSI Technical Committee Satellite Earth Stations and Systems
(SES).
Modal verbs terminology
In the present document "should", "should not", "may", "need not", "will", "will not", "can" and "cannot" are to be
interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Executive summary
The present document provides the rationale for the revision of the ETSI TCR Standard [i.1].
The need for such revision appeared mainly as a consequence of the evolution of satellites, with new operational
frequency bands and configurations like mega-constellations; the progress on spread spectrum technology; the quest for
more flexibility in frequency planning and operations on geostationary telecommunication satellite fleets; and novel
demands concerning the accommodation of hosted payloads and their segregated operations in those satellites.
Therefore, the existing standard was revised in the following areas: frequency plan, operational phases, hosted payload
management application, mega-constellation application, spread spectrum modulation, phase and frequency modulation
and finally, coding and interleaving.
The revision has borrowed from the experience acquired by suppliers, operators and space agencies as well as from
standards produced in other relevant standardization fora like the European Cooperation for Space Standardization
(ECSS) or the Consultative Committee for Space Data Systems (CCSDS).
In summary, the present document provides a sufficient justification of the revision with pointers to annexes and
relevant references for those readers seeking further detail.
ETSI
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5 ETSI TR 103 956 V1.1.1 (2018-12)
Introduction
The European Telecommunication Standards Institute (ETSI) established a telemetry, command and ranging (TCR)
standard ETSI EN 301 926 [i.2] in 2002.
In recent years telecommunication satellite operators have shown a renewed interest in spread spectrum systems. Their
improved performance under interference over the classical frequency modulation (FM) or phase modulation (PM)
could ease operations. In mission phases like orbit drift the TCR can be subject to interference while crossing the
equatorial orbital arc. With the emergence of electric orbit raising strategies, this phase has actually become much
longer making resistance to interference even more relevant.
In addition, hosted payloads are emerging as an attractive business proposition for telecommunication satellite
operators. The capability to have direct telecommand (TC) and telemetry (TM) communications with segregated
radiofrequency (RF) carriers and avionics could off-load to some extent hosted payload operations from satellite
operations. In addition, it could limit the interface impact between the satellite and the hosted payload respective ground
and space segments.
Meanwhile the technology of transponders/receivers as well as ground modems have evolved to support spread
spectrum modulation as well as frequency flexibility on FM/PM. For instance, the ability to acquire and track a spread
spectrum signal under high dynamics is no longer considered an issue, in contrast to the times when the first version of
the ETSI TCR standard was published. Such capability could simplify satellite TT&C sub-systems by eliminating the
need for dual-mode transponders (FM/PM and spread spectrum).
Moreover, mega-constellations for telecommunication missions are currently being developed. To accommodate a very
large number of new TCR carriers on existing bands, spread spectrum modulation could offer an efficient solution.
In consideration of all the above, ETSI initiated a work item to revise the standard in 2015. The goal was to match the
revised standard with the current and expected capabilities of transponders and ground modems for future
telecommunication missions, not only geostationary. ETSI EN 301 926 [i.1] revision has been published in 2017. The
present document, therefore, provides a description and justification of this revision.
Readers are encouraged to take into account that the present document builds upon and complements ETSI
TR 101 956 [i.3]. ETSI EN 301 926 (V1.3.1) [i.1] has not questioned the existing modulation trade-offs carried out for
the definition of the first issue of the standard.
Furthermore, it does not question the concept of Collocated Equivalent Capacity (CEC). However, it is recognized that
the addition of channel coding and interleaving will impact CEC by allowing to enhance capacity with respect to the
first version of the standard.
Following this introduction, the present document is organized as follows.
Clause 1 outlines the scope of the standard revision.
Clause 2 provides relevant informative references that can assist readers seeking a more detailed understanding of some
modifications.
Clause 3 recalls the terms and abbreviations employed throughout the document.
Clause 4 discusses the modifications impacting frequency planning and operational scenarios.
Clause 5 provides a detailed discussion of the key modifications affecting spread spectrum modulation like the
extension of the Pseudo-noise code family and others.
Clause 6 addresses key modifications affecting non-spread modulations.
Clause 7 introduces coding and interleaving options added to the standard.
Clause 8 gives a conclusion.
Finally, annexes A and B complement the main body of the document addressing detailed aspects, annex C provides
information for future possible work.
ETSI
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6 ETSI TR 103 956 V1.1.1 (2018-12)
1 Scope
The present document provides the rationale for the revision of the ETSI TCR Standard ETSI EN 301 926 [i.1] in the
following areas:
• frequency plan;
• operational phases;
• hosted payload management application;
• mega-constellation application;
• spread spectrum modulation;
• phase and frequency modulation; and
• coding and interleaving.
2 References
2.1 Normative references
Normative references are not applicable in the present document.
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI EN 301 926 (V1.3.1) (10-2017): "Satellite Earth Stations and Systems (SES); Radio
Frequency and Modulation Standard for Telemetry, Command and Ranging (TCR) of
Communications Satellites".
[i.2] ETSI EN 301 926 (V1.2.1) (06-2002): "Satellite Earth Stations and Systems (SES); Radio
Frequency and Modulation Standard for Telemetry, Command and Ranging (TCR) of
Geostationary Communications Satellites".
[i.3] ETSI TR 101 956: "Satellite Earth Stations and Systems (SES); Technical analysis of Spread
Spectrum Solutions for Telemetry Command and Ranging (TCR) of Geostationary
Communications Satellites".
[i.4] CCSDS 231.0-B-x: "TC Synchronization and Channel Coding".
[i.5] CCSDS 131.0-B-x: "TM Synchronization and Channel Coding".
NOTE: CCSDS standards always include the issue number on their numbering system; the parameter 'x' on
references [i.4] and [i.5] is understood as the highest published number and therefore latest issue of the
standard.
[i.6] IEEE Transactions on Information Theory: "Optimal Binary Sequences for Spread Spectrum
Multiplexing", R. Gold, vol. IT-13, no. 1, pp. 619-621, 1967.
ETSI
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7 ETSI TR 103 956 V1.1.1 (2018-12)
[i.7] NASA Publication Contract NAS 5-22546: "TDRSS Telecommunication System PN Code
Analysis final Report Addendum", R. Gold, Sept. 1977.
[i.8] Space Network Interoperability Group: "Space Network Interoperable PN Code Libraries",
Revision 1, Sept. 1998.
[i.9] CCSDS 230.1-G-x: "TC Synchronization and Channel Coding - Summary of Concept and
Rationale".
[i.10] CCSDS 130.1-G-x: "TM Synchronization and Channel Coding - Summary of Concept and
Rationale".
NOTE: CCSDS reports always include the issue number on their numbering system; the parameter 'x' on
references [i.9] and [i.10] is understood as the highest published number and therefore latest issue of the
standard.
[i.11] R. L. Miller, L. J. Deutsch, and S. A. Butman: "On the Error Statistics of Viterbi Decoding and the
Performance of Concatenated Codes". JPL Publication 81-9. Pasadena, California: JPL,
September 1, 1981.
[i.12] L. Deutsch, F. Pollara, and L. Swanson: "Effects of NRZ-M Modulation on Convolutional Codes
Performance". TDA Progress Report 42-77, January-March 1984 (May 15, 1984): 33-40.
[i.13] Space Network Users' Guide (SNUG). Revision 10. 450-SNUG. Greenbelt, Maryland: NASA
Goddard Space Flight Center, August 2012.
[i.14] I. Aguilar Sánchez et al.: "The Navigation and Communication Systems for the Automated
Transfer Vehicle", proceedings of the IEEE 49th Vehicular Technology Conference, Vol. 2,
pp. 1187-1192, 1999.
[i.15] G. Lesthievent et al.: "Concatenating the convolutional (7,1/2) code with the BCH in TED mode
with CRC for improved TC link in the CNES Myriad satellites family", Paper SLS-NGU-10-
CNES01, CCSDS Next Generation Uplink Working Group, London (UK), October 2010.
[i.16] CCSDS 231.1-O-1: "Short Block Length LDPC Codes for TC Synchronization and Channel
Coding".
[i.17] ECSS-E-ST-50-05C Rev. 2: "Space Engineering - Radio frequency and modulation", European
Cooperation for Space Standardization, 4 October 2011.
[i.18] NIST: "Advanced Encryption Standard (AES)", Federal Information Processing Standard
Publication 197, United States, November 26, 2001.
[i.19] NIST Special Publication 800-38A: "Recommendation for Block Cipher Modes of Operation:
Methods and Techniques", United States, December 2001.
3 Definition of terms and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
binary channel: binary communications channel (BPSK has 1 channel, QPSK has 2 channels)
channel symbol rate: rate of binary elements, considered on a single wire, after FEC coding and channel allocation
NOTE: See Figures 2, 3 and 4. This applies only to multi-channel modulations, thus to spread spectrum QPSK
modes and not to PM/FM modes.
Co-located Equivalent Capacity (CEC): number of collocated satellites that can be controlled with a perfect power
balanced link between the ground and the satellite
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8 ETSI TR 103 956 V1.1.1 (2018-12)
Code Division Multiple Access (CDMA): technique for spread-spectrum multiple-access digital communications that
creates channels through the use of unique code sequences
Command Link Transmission Unit (CLTU): telecommand protocol data structure providing synchronization for the
codeblock and delimiting the beginning of user data
NOTE: See [i.4], section 4 for further details.
data rate: total number of uncoded data bits per second after packet and frame encoding
NOTE: See Figures 1 to 4. This is the data rate used in link budgets in ETSI TR 101 956 [i.3].
Direct Sequence Spread Spectrum (DSSS): form of modulation where a combination of data to be transmitted and a
known code sequence (chip sequence) is used to directly modulate a carrier, e.g. by phase shift keying
symbol rate: rate of binary elements, considered on a single wire, after FEC coding
NOTE: See Figures 1 to 4.
MTC1 / MTM1
Ranging
Tones
RF
Carrier
PM or FM
Modulation
Symbol Rate
Subcarrier
Data Waveform BPSK
Channel Coding
Source Formating Modulation
Scope of this Document
Channel Coding
Bit Rate
Pseudo- Differential Convolutional
Block Code
Start Sequence
(optional) Randomizer Coder Coder
ASM
BCH, R-S, LDPC
(optional) (optional) (optional)
Figure 1: Functional stages of transmit chain for FM/PM modulation (MTC1/MTM1)
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Figure 2: Functional stages of transmit chain for spread spectrum modulation MTC2
Figure 3: Functional stages of transmission chain for spread spectrum modulation MTC
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10 ETSI TR 103 956 V1.1.1 (2018-12)
MTM2 / MTM3
Chip Rate I Ch. PN Code
I Channel
Waveform
BPSK
Formating
Modulation
Symbol Rate
RF
Carrier
Data Channel Coding
Channel Symbol Rate
Source (*)
(*) Refer to
MTC1 / MTM1
Q Channel
Waveform
BPSK
Formating
Modulation
Chip Rate Q Ch. PN Code
Scope of this Document
Figure 4: Functional stages of transmission chain for spread spectrum modulation MTM2/MTM3
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AES Advanced Encryption Standard
ATV Automated Transfer Vehicle
BCH Bose-Chaudhuri-Hocquenghem
BER Bit Error Rate
BPSK Binary Phase Shift Keying
CCSDS Consultative Committee for Space Data Systems
CDMA Code Division Multiple Access
CEC Co-located Equivalent Capacity
CLTU Command Link Transmission Unit
CMM Carrier Modulation Modes
CNES Centre National d'Etudes Spatiales
CRC Cyclic Redundancy Check
CW Continuous Wave
DC Direct Current
DSSS Direct Sequence Spread Spectrum
ECSS European Cooperation for Space Standardization
FEC Forward Error Correction
FM Frequency Modulation
GSID Ground-to-Satellite Interface Specification
GSO Geo-Stationary Orbit
GTO Geostationary Transfer Orbit
I In-phase
LDPC Low Density Parity Check
LEO Low Earth Orbit
LEOP Launch and Early Orbit Phase
MAI Multiple Access Interference
MTC1 TeleCommand Mode 1
MTC2 TeleCommand Mode 2
MTC3 TeleCommand Mode 3
MTM1 TeleMetry Mode 1
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11 ETSI TR 103 956 V1.1.1 (2018-12)
MTM2 TeleMetry Mode 2
MTM3 TeleMetry Mode 3
NASA National Aeronautics and Space Administration (USA)
NIST National Institute of Standards and Technology
NRZ Non-Return Zero
NRZ-L Non Return to Zero-Level
NRZ-M Non Return to Zero-Mark
NTIA National Telecommunications Industry Association
PDF Probability Density Function
PED Phase Error Detector
PLL Phase Locked Loop
PLOP Physical Layer Operating Procedures
PM Phase Modulation
PN Pseudo Noise
Q Quadrature
QPSK Quaternary Phase Shift Keying
RF Radio Frequency
RS Reed-Solomon
SEC Single Error Correction
SER Symbol Error Rate
SNR Signal to Noise Ratio
SSTO Single-Stage-To-Orbit
TC TeleCommand
TCR Telemetry, Command and Ranging
TDRSS Tracking and Data Relay Satellite System (NASA)
TED Triple Error Detection
TM TeleMetry
TT&C Telemetry, Tracking and Command
VLSI Very Large Scale Integration
4 Frequency Planning and Operational Scenarios
4.1 Frequency Planning
4.1.1 Frequency Bands
a) C-band: 5 850 MHz to 6 725 MHz uplink, 3 400 MHz to 4 200 MHz downlink;
b) Ku-band: 12 750 MHz to 14 800 MHz and 17 300 MHz to 18 100 MHz uplink, 10 700 MHz to 12 750 MHz
downlink;
c) Commercial Ka-band: 27 500 MHz to 30 000 MHz uplink, 17 700 MHz to 20 700 MHz downlink.
It should be noted that these bands are due to prevailing regulations, not physics. Possible usage of the TCR techniques
considered in the present document and ETSI EN 301 926 [i.1] in adjacent bands between 1 GHz and 44 GHz may be
envisaged.
4.1.2 Frequency Flexibility
Modern command receivers and telemetry transmitters often utilize fractional N phase-locked loop (PLL) synthesizers
for frequency generation. It is possible to generate different output frequencies from a single input reference frequency
using this technology. The frequency resolution of such synthesizers is very high, in the order of a few Hertz, which is
clearly more than needed for communication satellite transceivers.
For practical purposes, a 100 kHz resolution is recommended. This is based on experience from commercial programs,
which already use frequency flexibility and also the fact that the resolution does not need to be higher than the downlink
frequency stability requirement of ±5 ppm [i.1], clause 5.1.2.
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12 ETSI TR 103 956 V1.1.1 (2018-12)
4.2 Hosted Payloads
Hosted payloads are emerging as an attractive business proposition for telecommunication satellite operators. When
additional "Hosted" payloads are embarked on a given "Host" satellite, they may require telemetry and command
functionalities beyond what the host's heritage hardware is designed for. The traditional concept for the command and
telemetry of hosted payloads relies on a tight share of the classical TCR and spacecraft platform avionics resources by
means of data multiplexing mechanisms and the common spacecraft computer and applications software.
An alternative design solution consists on adding dedicated TCR hardware to the hosted payload. Thus, monitoring and
control can be carried out independently of the host, decoupled from host avionics and data handling. The resulting
reduction of interface control documentation between host and hosted payload is an additional advantage. It is a use
case considered as natural for minimally intrusive and spectrally robust TCR systems. Since the hosted payload TCR
use case is in effect a separate payload that just happens to be on the same structure as the host, the same TCR standards
apply as for the host.
In addition, such architecture can off-load to some extent hosted payload operations from satellite operations. Thus,
higher levels of operational autonomy can be reached and offered to hosted payload operators in contrast to the classical
operations concept.
4.3 Operation during Launch and Early Orbit
After successful launch and separation all satellites have a Low Earth Orbit Phase (LEOP) while propulsive manoeuvres
are performed to get the spacecraft to their intended final orbit. TCR is also needed in this phase.
The main TCR consequences of LEOP are due to geometry. The spacecraft is moving differently (and generally faster)
than in the final orbit, the link ranges ma
...