IEC 63098-2:2022

Transmitting and receiving equipment for radiocommunication - Radio-over-fibre technologies and their performance standard - Part 2: Radio-over-fibre-based fronthaul network for railway communication systems

IEC 63098-2:2022 provides the required performance with reliability and quality assurance of radio-over-fiber-based fronthaul networks for railway communication networks between trains and tracksides, as well as a design guide for network configuration. A high-speed train communication network comprises two parts: a back-end network and wireless access system to deliver data to train cars. In this back-end network, optical fiber communication-based networks are generally utilized to reduce the complexity of the radio access units set along the railway track, which delivers the signal wirelessly to the train car, wireless signals are generated and processed at a central office, and then are transported via an optical fiber network into the radio access units. A radio-over-fiber fronthaul network is configured to transport the wireless signal, which is applicable between a node base station and radio access units set at a trackside. The radio-over-fiber-based fronthaul link connects the node base station to the trackside radio access units and carries millimeter-wave subcarrier or intermediate frequency components to transmit high-capacity signals.

General Information

• Status: Published
• Publication Date: 06-Dec-2022
• ICS: 33.060.20 - Receiving and transmitting equipment
• Technical Committee: TC 103 - Transmitting and receiving equipment for radiocommunication
• Drafting Committee: WG 6 - TC 103/WG 6
• Current Stage: PPUB - Publication issued
• Start Date: 23-Dec-2022
• Completion Date: 07-Dec-2022

Standards Content (Sample)

IEC 63098-2
®

Edition 1.0 2022-12
INTERNATIONAL
STANDARD

colour
inside


Transmitting and receiving equipment for radiocommunication – Radio-over-
fibre technologies and their performance standard –
Part 2: Radio-over-fibre-based fronthaul network for railway communication
systems
IEC 63098-2:2022-12(en)

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IEC 63098-2

®


Edition 1.0 2022-12




INTERNATIONAL



STANDARD








colour

inside










Transmitting and receiving equipment for radiocommunication – Radio-over-

fibre technologies and their performance standard –

Part 2: Radio-over-fibre-based fronthaul network for railway communication

systems
























INTERNATIONAL

ELECTROTECHNICAL


COMMISSION





ICS 33.060.20 ISBN 978-2-8322-6056-2




  Warning! Make sure that you obtained this publication from an authorized distributor.


® Registered trademark of the International Electrotechnical Commission

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– 2 – IEC 63098-2:2022  IEC 2022
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 7
3.1 Terms and definitions . 7
3.2 Abbreviated terms . 8
4 Functional specification . 8
4.1 RoF fronthaul network . 8
4.2 RoF transmitter and receiver . 9
4.3 Operating environment . 9
5 Testing . 9
5.1 General . 9
5.2 Performance testing . 9
6 Environmental specifications . 9
6.1 General safety . 9
6.2 Laser safety . 10
6.3 Temperature and environment . 10
Annex A (normative) Specifications for RoF fronthaul networks in railway
communication systems . 11
A.1 Overview. 11
A.2 Diagrams . 12
A.2.1 Optical switch-based system . 12
A.2.2 WDM-based system . 12
A.3 Functional specification. 13
A.4 Testing . 14
A.4.1 General . 14
A.4.2 Performance testing. 14
Annex B (informative) Specifications for the DSB RoF transmitter for fronthaul
systems in railway communication systems . 15
B.1 Overview. 15
B.2 Diagrams . 16
B.3 Functional specification. 17
B.4 Testing . 17
B.4.1 General . 17
B.4.2 Characterization testing . 17
B.4.3 Performance testing. 17
Annex C (informative) Specifications for SSB RoF transmitter for fronthaul system in
railway communication systems . 18
C.1 Overview. 18
C.2 Diagrams . 18
C.3 Functional specification. 19
C.4 Testing . 19
C.4.1 General . 19
C.4.2 Characterization testing . 19
C.4.3 Performance testing. 19

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IEC 63098-2:2022  IEC 2022 – 3 –
Bibliography . 20

Figure 1 – Block diagram of RoF fronthaul network for a railway communication system . 9
Figure A.1 – Schematic diagram of a railway communication system . 11
Figure A.2 – Block diagram of optical-switch-based fronthaul network . 12
Figure A.3 – Block diagram of WDM-based fronthaul network . 13
Figure B.1 – Relative RF throughput of the DSB-modulated signals over some length of
the optical fibre at a centre frequency of 3 GHz and 15 GHz . 16
Figure B.2 – Block diagram of DSB RoF transmitter with (a) external modulation and

(b) direct modulation systems . 16
Figure B.3 – Block diagram of DSB RoF transmitter with (a) external modulation and
(b) direct modulation systems for the WDM-based network . 17
Figure C.1 – Block diagram of SSB RoF transmitter with (a) DSB E/O with an optical
filter, (b) DD-MZM-based system and (c) IQ-modulator-based systems . 18

Table 1 – Abbreviated terms . 8
Table 2 – Operating environment . 9
Table A.1 – Functional specification of the RoF fronthaul network . 14
Table A.2 – Performance test plan . 14
Table B.1 – Functional specification of DSB RoF transmitter . 17
Table C.1 – Functional specification of SSB RoF transmitter . 19

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– 4 – IEC 63098-2:2022  IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

TRANSMITTING AND RECEIVING EQUIPMENT FOR
RADIOCOMMUNICATION – RADIO-OVER-FIBRE
TECHNOLOGIES AND THEIR PERFORMANCE STANDARD –

Part 2: Radio-over-fibre-based fronthaul network
for railway communication systems

FOREWORD
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IEC 63098-2 has been prepared by IEC technical committee 103: Transmitting and receiving
equipment for radiocommunication. It is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
103/244/FDIS 103/249/RVD

Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.

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IEC 63098-2:2022  IEC 2022 – 5 –
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 63098 series, published under the general title Transmitting and
receiving equipment for radiocommunication – Radio‑over-fibre technologies and their
performance standard, can be found on the IEC website.
Future documents in this series will carry the new general title as cited above. Titles of existing
documents in this series will be updated at the time of the next edition.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

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– 6 – IEC 63098-2:2022  IEC 2022
INTRODUCTION
A high-speed train communication network comprises two parts: a back-end network and
wireless access system to deliver data to train cars. In this back-end network, optical fiber
communication-based networks are generally utilized to reduce the complexity of the radio
access units set along the railway track, which delivers the signal wirelessly to the train car,
wireless signals are generated and processed at a central office, and then are transported via
an optical fiber network into the radio access units. A radio-over-fiber fronthaul network is
configured to transport the wireless signal, which is applicable between a node base station
and radio access units set at a trackside. The radio-over-fiber-based fronthaul link connects the
node base station to the trackside radio access units and carries millimeter-wave subcarrier or
intermediate frequency components to transmit high-capacity signals. This document provides
the required performance with reliability and quality assurance of radio-over-fiber-based
fronthaul networks for railway communication networks between trains and tracksides, as well
as a design guide for network configuration.

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IEC 63098-2:2022  IEC 2022 – 7 –
TRANSMITTING AND RECEIVING EQUIPMENT FOR
RADIOCOMMUNICATION – RADIO-OVER-FIBRE
TECHNOLOGIES AND THEIR PERFORMANCE STANDARD –

Part 2: Radio-over-fibre-based fronthaul network
for railway communication systems



1 Scope
This part of IEC 60598 specifies a radio-over-fiber-based fronthaul network for railway
communication systems between trains and tracksides and their transmitters and receivers.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60950-1, Information technology equipment – Safety – Part 1: General requirements
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1.1
radio over fiber
RoF
radio signal transmission method using an optical fiber whose signal is modulated by the radio
signal
3.1.2
double-sideband modulation
modulation pertaining to a transmission or emission where both sidebands resulting from
amplitude modulation are preserved equally
3.1.3
single-sideband modulation
modulation pertaining to a transmission or emission where only either the lower sideband or the
upper sideband resulting from amplitude modulation is preserved

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– 8 – IEC 63098-2:2022  IEC 2022
3.1.4
wavelength division multiplexing
WDM
multiplexing in which several independent signals are allotted separate wavelengths for
transmission over a common optical transmission medium
[SOURCE: IEC 60050-704:2019, 704-08-06, modified – The Note 1 to entry has been deleted.]
3.2 Abbreviated terms
The abbreviated terms used in this document are listed in Table 1.
Table 1 – Abbreviated terms
CO central office
DeMUX demultiplexer
DSB double sideband
DUT device under test
E/O electrical-to-opt
...