ETSI TS 101 601 V1.2.1 (2013-02)

Technical Specification
Electromagnetic compatibility
and radio spectrum matters (ERM);
The specification and implementation of design changes to
interrogators and specification of the test plan for
the Preliminary Tests and the Trial;
Modification of interrogators and specification of
test plans for the Preliminary Tests and Trial

2 ETSI TS 101 601 V1.2.1 (2013-02)

Reference
RTS/ERM-TG34-312
Keywords
DAA, ER-GSM, radio, RFID
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ETSI
3 ETSI TS 101 601 V1.2.1 (2013-02)
Contents
Intellectual Property Rights . 4
Foreword . 4
Introduction . 4
1 Scope . 5
2 References . 5
2.1 Normative references . 5
2.2 Informative references . 5
3 Definitions, symbols and abbreviations . 6
3.1 Definitions . 6
3.2 Symbols . 6
3.3 Abbreviations . 6
4 Background Information . 7
5 RFID Interrogator modifications . 7
5.1 System concept . 7
5.2 Hardware modifications . 7
5.2.1 RFID specific . 7
5.2.2 Railways specific . 8
5.3 Software modifications . 9
6 RFID Interrogator acceptance test . 9
6.1 RFID standards . 9
6.2 ETSI standards . 9
6.3 (E)R-GSM mitigation tests . 9
6.3.1 (E)R-GSM detection and decoding . 9
6.3.2 Detection at start-up of interrogator . 9
6.3.3 Detection at start-up of (E)R-GSM BTS . 10
6.4 Acceptance test results . 10
Annex A (informative): UHF RFID Interrogator modification description . 11
Annex B (informative): UHF RFID Interrogator acceptance test results . 15
B.1 Introduction . 15
B.2 RFID standards . 15
B.3 ETSI standards . 17
B.3.1 Interrogator spectrum mask . 17
B.3.2 Tag spectrum mask . 22
B.4 (E)R-GSM mitigation tests . 25
B.4.1 (E)R-GSM detection and decoding . 25
B.4.2 Detection at start-up of interrogator . 26
B.4.3 Detection at start-up of (E)R-GSM BTS . 28
Annex C (informative): Bibliography . 31
History . 32

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4 ETSI TS 101 601 V1.2.1 (2013-02)
Intellectual Property Rights
IPRs essential or potentially essential to the present document 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 (http://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.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Electromagnetic compatibility and
Radio spectrum Matters (ERM).
Introduction
In order to accommodate the spectrum needs for the increasing number of RFID devices and systems, an extension band
for high power RFID systems in the range between 915 MHz and 921 MHz has been requested. This band is already
used by RFID in several countries worldwide and its designation in Europe would increase its functionality and simplify
the international movement of goods using RFID identification systems. In Europe, a part of this new frequency band
has to be shared between the primary user ER-GSM and RFID. In order to guarantee an interference-free coexistence
between the two systems, mechanisms have to be implemented by RFID systems to reduce the probability of
interference to an acceptable minimum. These techniques can be either of regulatory, technical or operational nature.
The present document includes a description of the modifications made to the hardware and software of two UHF RFID
interrogators in order to implement demonstrators with the Detect And Avoid (DAA) technique defined in
TS 102 902 [i.1] and TS 102 903 [i.2]. In addition a specification of acceptance tests for the modified interrogators is
provided.
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5 ETSI TS 101 601 V1.2.1 (2013-02)
1 Scope
The present document specifies the practical implementation of the DAA mitigation technique for UHF RFID systems
sharing the band 918 MHz to 921 MHz with ER-GSM. It covers the required modifications to UHF RFID interrogators
as well as the subsequent acceptance tests. The purpose of the modified interrogators, (also called demonstrators) is to
validate a subset of the mitigation techniques specified in [i.1] and [i.2]. The present document only covers the design
modification and acceptance tests.
The system tests carried out together with ER-GSM will be covered in TR 101 602 [i.7].
2 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.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
[1] ETSI EN 302 208 (V1.4.1): "Electromagnetic compatibility and Radio spectrum Matters (ERM);
Radio Frequency Identification Equipment operating in the band 865 MHz to 868 MHz with
power levels up to 2 W".
2.2 Informative references
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 TS 102 902: "Electromagnetic compatibility and radio spectrum matters (ERM); Methods,
parameters and test procedures for cognitive interference mitigation towards ER-GSM for use by
UHF RFID using Detect-And-Avoid (DAA) or other similar techniques".
[i.2] ETSI TS 102 903: "Electromagnetic compatibility and Radio spectrum Matters (ERM);
Compliance tests for cognitive interference mitigation for use by UHF RFID using Detect-And-
Avoid (DAA) or other similar techniques".
[i.3] EIRENE System Requirements Specification Version 15.1.
[i.4] ETSI TS 144 018: "Digital cellular telecommunications system (Phase 2+); Mobile radio interface
layer 3 specification; Radio Resource Control (RRC) protocol (3GPP TS 44.018 version 10.6.0
Release 10)".
[i.5] ETSI TR 102 649-2: "Electromagnetic compatibility and Radio spectrum Matters (ERM);
Technical characteristics of Short Range Devices (SRD) and RFID in the UHF Band; System
Reference Document for Radio Frequency Identification (RFID) and SRD equipment; Part 2:
Additional spectrum requirements for UHF RFID, non-specific SRDs and specific SRDs".
[i.6] ISO/IEC 18000-6:2010: "Information technology -- Radio frequency identification for item
management -- Part 6: Parameters for air interface communications at 860 MHz to 960 MHz".
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6 ETSI TS 101 601 V1.2.1 (2013-02)
[i.7] ETSI TR 101 602: "Electromagnetic compatibility and Radio spectrum Matters (ERM); Technical
Report on Preliminary Tests and Trial to verify mitigation techniques for sharing spectrum
between RFID and ER-GSM".
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
Detect And Avoid (DAA): technique to protect radio communication services by avoiding co-channel operation.
NOTE: Before transmitting, a system senses the channel within its operational bandwidth in order to detect the
possible presence of other systems. If a channel is occupied, the system avoids transmission on this
channel until it becomes available.
Downlink (DL): direction of communication from master to slave, where in the case of a typical RFID system the
direction flows from the interrogator to tag
fixed: physically fixed, non- moving device; includes temporary installations as well
Listen Before Talk (LBT): spectrum access protocol requiring a cognitive radio to perform spectrum sensing before
transmitting
location awareness: capability that allows a device to determine its location to a defined level of precision
mobile: physically moving device
Uplink (UL): direction of communication from Slave to Master
3.2 Symbols
For the purposes of the present document, the following symbols apply:
dB decibel
f frequency measured under normal test conditions
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ARFCN Absolute Radio Frequency Channel Number
BCCH Broadcast Control CHannel
BLF Backscatter-Link Frequency
BTS Base Transceiver Station
DAA Detect And Avoid
DL DownLink
e.r.p. effective radiated power
ECC Electronic Communications Committee
EEPROM Electrically Erasable and Programmable Read Only Memory
EIRENE European Integrated Railway Radio Enhanced Network
ER-GSM Extended Railways GSM
GSM Global System for Mobile communication
GSM-R GSM - Railway
IE Information Element
LBT Listen Before Talk
M Number of subcarrier cycles per symbol
RFID Radio Frequency IDentification
R-GSM Railways Global System for Mobile communications
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7 ETSI TS 101 601 V1.2.1 (2013-02)
Tari Reference time interval for a data-0 in Interrogator-to-tag signalling
TCH Traffic CHannel
TX Transmitter
UHF Ultra High Frequency
UL UpLink
4 Background Information
The present document specifies the requirements for test interrogators (demonstrators) as needed for validation of the
successful co-existence of RFID with ER-GSM when operating in the same frequency band. The railways require a
comprehensive trial of the mitigation technique before giving their formal agreement for RFID to share the band with
ER-GSM. A successful outcome to the trial will also assist ECC in recommending the designation of additional
spectrum for RFID at UHF.
The European Commission has identified RFID as a technology that can bring fundamental improvements to the
Community. This is not only in terms of improvements to the efficiency of business but also in terms of the quality of
people's lives. Already RFID is being adopted at an increasing rate across a wide range of applications. For example in

2010 global sales of RFID tags at UHF grew to 1,2 billion (see note), which is 73 % higher than market predictions. By
2022 it is estimated that the global annual consumption of tags at UHF will have reached 86 billion (see note).
NOTE: Source IDTechEx.
To make provision for this growth in demand, in 2008 ETSI submitted a request to ECC for additional spectrum at UHF
for RFID. Details of this request are described in SRDoc TR 102 649-2 [i.5]. The document identified that the
frequency range 915 MHz to 921 MHz, which acts as a guard band between the uplink and downlink for GSM, was
substantially unused. ECC was asked to consider whether this band could be designated for use by RFID.
Not long afterwards the railways requested the extension of the GSM-R band to include the frequency range
918 MHz to 921 MHz paired with 873 MHz to 876 MHz. The ECC agreed to this request. In subsequent discussions
between the railways and ERM_TG34, the railways agreed to share the band with RFID systems with one obligation,
RFID community has to provide reliable techniques to ensure GSM-R operation without causing harmful interferences.
5 RFID Interrogator modifications
5.1 System concept
The RFID interrogators to be used as demonstrators should be developed to support downlink detection of the R-GSM
or ER-GSM signal. The downlink detection may be done by use of an external receiver, or the RFID receiver, which
also detects the tag responses. The antenna could be a dedicated antenna to receive the R-GSM/ER-GSM transmissions,
or instead one or more of the RFID antennas may be used.
The demonstrators shall support the data rates and subcarriers intended for the 400 kHz RFID TX channels and the
1 200 kHz channel spacing.
5.2 Hardware modifications
5.2.1 RFID specific
The demonstrators shall support at least the combinations of forward and return link settings as specified in Table 1.
Table 1: Forward and return link settings
Forward link Return link
Tari <= 10 µs (towards 6,25 µs) M=4, BLF = 320 kHz
Tari <= 10 µs (towards 6,25 µs) M=4, BLF = 640 kHz

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8 ETSI TS 101 601 V1.2.1 (2013-02)
The demonstrators shall support the following transmit channels as in Table 2.
Table 2: Forward and return link settings
Frequency/MHz Comment
916,3 See note 1
917,5 See note 1
918,7 See note 1
919,9 See note 1
919,3 See note 2
920,5 See note 2
921,7 See note 2
922,9 See note 2
NOTE 1: For use if ER-GSM band is supported by
railways test equipment.
NOTE 2: For use if ER-GSM band is not supported by
railways test equipment and instead the
channel frequencies have to be shifted by
3 MHz to be able to use R-GSM equipment.

5.2.2 Railways specific
Each demonstrator shall have means to detect BCCH channels in the R-GSM band and ER-GSM band.
The demonstrator shall be capable of scanning the (E)R-GSM downlink band and receive signals from the BCCH
channel in the whole (E)R-GSM band. The demonstrator shall successfully receive and decode the BCCH transmission
of each carrier identified in that spectrum. The message of relevance within the Broadcast Channel is the SYSTEM
INFORMATION TYPE 1 (see clause 9.1.31 of TS 144 018 [i.4]) message containing the Cell Channel Description IE.
From the received information corresponding to the BCCH Cell Channel Description IE, the demonstrators shall create
a list of all ARFCN used by (E)R-GSM in the local area of operation.
The detection of the BCCH information shall be possible down to -98 dBm, which is the minimum coverage power
level specified for non-high speed railways tracks (see [i.3]).
The demonstrator shall not use any of the RFID TX channels with a centre frequency of less than 700 kHz away from
the centre frequency of any channel stored in the ARFCN list, if the received GSM-R power level is ≥ -98 dBm.
Figure 1 shows which ER-GSM channels prevent the use of either the 918,7 MHz or the 919,9 MHz RFID TX channel.
918.7
RFID Channel
Frequency / MHz
ER-GSM Channel
918 919 920 921
919.9
Frequency / MHz
919 920 921
Figure 1: Illustration of interference between ER-GSM and RFID channels
Each demonstrator shall perform the BCCH and TCH detection routine after turn-on and thereafter at selectable
intervals ≤ 60 seconds.
NOTE: As a detection interval of 24 hour interval is not applicable for testing purposes, 60 seconds have been
selected instead.
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9 ETSI TS 101 601 V1.2.1 (2013-02)
5.3 Software modifications
Each demonstrator shall provide the means to select or deselect any channel from Table 2. This is required in order to
switch between R-GSM and ER-GSM band tests, as well as to emulate that certain channels are not available.
Furthermore, the demonstrator shall implement the detection period as in clause 5.2.2.
6 RFID Interrogator acceptance test
6.1 RFID standards
The demonstrator shall fulfil ISO/IEC 18000-6:2010 [i.6] Type C as far as required for these tests.
In particular the following parameters will be verified as specified in clause 5.2.1:
• Tari
• M
• BLF
6.2 ETSI standards
Based on the principle test methods of EN 302 208 [1] the following items shall be tested as specified in
SRDoc TR 102 649-2 [i.5]:
• Interrogator spectrum mask (EN 302 208-1 (V1.4.1) [1], clauses 8.3, 8.4 and 8.5; SRDoc TR 102 649-2 [i.5],
clauses 7.2.2 and B.1.3).
• Tag spectrum mask (EN 302 208-1 (V1.4.1) [1], clause 10; SRDoc TR 102 649-2 [i.5], clauses 7.2.2 and
B.1.3).
6.3 (E)R-GSM mitigation tests
This clause defines the requirements for a RFID interrogator operating in the ER-GSM band to prove its capabilities to
detect and identify a BCCH channel and to respond as required in clause 5.2.2.
6.3.1 (E)R-GSM detection and decoding
This test is to show the interrogator's capability to receive and to decode a transmitted (E)R-GSM BCCH properly. It
shall be repeated for three different GSM-R received signal levels (-60 dBm, -85 dBm and -98 dBm) and at least three
different ARFCNs. The test interrogator shall store the ARFCN channels and present the resulting channel list via a
serial terminal or as text file. The test passes if the TCHs reported match those transmitted in the Cell Channel
Description IE and the interrogator stops transmitting in the channels overlapping with ER-GSM.
6.3.2 Detection at start-up of interrogator
This test shall be done to confirm that the interrogator does detect ER-GSM channels at start-up of the interrogator.
For this test a channel in the ER-GSM band shall be allocated for railway use. After turning on the interrogator it shall
report the used ER-GSM channels for railways within 60 seconds and furthermore will have demonstrated that the
relevant RFID channel has been removed from the RFID channel select list.
This test shall be repeated 5 times for of each of the three different GSM-R received signal levels -60 dBm, -85 dBm
and -98 dBm and the test passes if the interrogator correctly reports the ER-GSM channels allocated for railway use and
avoids them accordingly.
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10 ETSI TS 101 601 V1.2.1 (2013-02)
6.3.3 Detection at start-up of (E)R-GSM BTS
This test shall be done to confirm that the interrogator does detect ER-GSM channels at start-up of a GSM-R BTS.
For this test an interrogator shall be running and a BTS signal shall be turned on with a channel in the ER-GSM band
allocated for railway use. After turning on the BTS the interrogator shall report the used ER-GSM channels for railways
within 60 seconds and furthermore will have demonstrated that the relevant RFID channel has been removed from the
RFID channel select list.
This test shall be repeated 5 times for of each of the three different GSM-R received signal levels -60 dBm, -85 dBm
and -98 dBm and the test passes if the interrogator correctly reports the ER-GSM channels allocated for railway use and
avoids them accordingly.
6.4 Acceptance test results
On completion of the acceptance tests, the results will be added in annex B as a revision of the present document.
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11 ETSI TS 101 601 V1.2.1 (2013-02)
Annex A (informative):
UHF RFID Interrogator modification description
The demonstrator consists of two essential components. These are the modified interrogator with its connected antenna
and the GSM-R Detector.
The GSM-R Detector is connected to the interrogator via its USB Host Interface. The detector is an external GSM
device which scans for the presence of BCCH and TCH signals within the dedicated frequency band. The detected
signals and power levels are transmitted to the interrogator via its USB Host interface. The interrogator detects and
analyses the received information and decides whether a channel is available or not.
Further the interrogator is connected to a PC which is used as monitoring device. Via the serial RS232 interface all
internal processes can be displayed by means of a console program like Terra-term or the Windows Hyper Terminal.
The detected GSM-R channels and the detected power levels are sent via. the TCP/IP Interface. These can be displayed
by the PC with a Visualization Software. The PC is just used for demonstration purposes and is not essential for the
operation of the interrogator.
Figure A.1 gives a quick overview on the general arrangement of the components and the cabling.

Figure A.1: Schematic of the demonstrator setup
The following clauses will give an overview on the procedures and structure inside the interrogator. The interrogator
can be divided into 4 different blocks as shown in Figure A.2.
ETSI
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