ETSI TR 103 403 V1.1.1 (2017-06)

Intelligent Transport Systems (ITS); Mitigation techniques to avoid harmful interference between equipment compliant with ES 200 674-1 and ITS operating in the 5 GHz frequency range; Evaluation of mitigation methods and techniques

DTR/ITS-00434

General Information

• Status: Published
• Publication Date: 12-Jun-2017
• Technical Committee: ITS WG4 - Media and Medium related
• Current Stage: 12 - Completion
• Due Date: 20-Jun-2017
• Completion Date: 13-Jun-2017

Standards Content (Sample)

ETSI TR 103 403 V1.1.1 (2017-06)






TECHNICAL REPORT
Intelligent Transport Systems (ITS);
Mitigation techniques to avoid harmful interference
between equipment compliant with ES 200 674-1 and
ITS operating in the 5 GHz frequency range;
Evaluation of mitigation methods and techniques

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2 ETSI TR 103 403 V1.1.1 (2017-06)




Reference
DTR/ITS-00434
Keywords
ITS, regulation

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3 ETSI TR 103 403 V1.1.1 (2017-06)

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 Definitions, symbols and abbreviations . 7
3.1 Definitions . 7
3.2 Symbols . 7
3.3 Abbreviations . 7
4 HDR-DSRC . 8
4.1 Operational characteristics . 8
4.2 Technical characteristics . 10
4.2.1 Roadside unit . 10
4.2.2 Onboard unit . 11
4.3 Protocol characteristics . 12
4.4 Interference characteristics . 12
5 Measurements . 13
5.1 Test architecture . 13
5.1.1 General approach . 13
5.1.2 Test signals . 17
5.1.2.1 ITS test signal . 17
5.1.2.2 HDR-DSRC test signal . 17
5.1.3 Test procedure . 17
5.1.4 Test scenarios . 18
5.2 Evaluation of test equipment . 18
5.2.1 ITS station units . 18
5.2.2 Equipment at the German test site . 19
5.3 Tests . 20
5.3.1 No interference . 20
5.3.2 Single interferer . 20
5.3.2.1 Tests on toll plaza . 20
5.3.2.2 Tests in anechoic chamber . 20
5.3.2.2.1 Test set-up A . 20
5.3.2.2.2 Test set-up B . 22
5.3.2.3 Final tests on toll site. 23
5.3.3 Multiple interferers . 26
5.3.3.1 Tests on toll plaza . 26
5.3.3.2 Tests in anechoic chamber . 28
5.4 Summary of results . 29
5.4.1 Critical scenarios . 29
5.4.2 Coexistence scenarios . 29
5.4.3 Summary of performed tests and their results. 29
6 Mitigation techniques . 29
6.1 Techniques for CEN DSRC. 29
6.2 Techniques for HDR-DSRC . 29
7 ETSI plug test . 29
Annex A: Statistical prediction . 31
History . 33

ETSI

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4 ETSI TR 103 403 V1.1.1 (2017-06)

Intellectual Property Rights
Essential patents
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 (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 Intelligent Transport Systems (ITS).
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 is about mitigation techniques to avoid or lower harmful interference of ITS radio transmitters
operating in the 5,9 GHz band upon 5,8 GHz backscatter communication systems used for e.g. electronic fee collection.
The present document comprises the evaluation of mitigation techniques specified in ETSI TS 102 792 [i.7] and their
applicability for the High Data Rate - DSRC (HDR-DSRC) technology standardized by UNINFO in Italy and by ETSI
ES 200 674-1 [i.1] used for road tolling.
As a global result it can be concluded that the mitigation techniques standardized in [i.7] for the CEN-DSRC technology
(also referred to as Medium Data Rate - DSRC (MDR-DSRC), and recently named TTT DSRC as the term to be used in
the future) are sufficient to avoid harmful interference to HDR-DSRC.
In order to perform the tests of which the results are reported in the present document, off-the-shelf equipment was used
and no further calibration was performed. The transmit power of the ITS signal in the 5,9 GHz band could be tuned
from 10 dBm EIRP to 23 dBm EIRP. The length of the ITS signals in terms of number of bytes could be adjusted
within the limits allowed by this technology. The message repetition interval was set to either 10 ms or 100 ms. The
HDR-DSRC system was operated with a test application (echo message of adjustable length), applying normal
operational radio parameter settings (these could not be changed).
The performed measurements were compared with a statistical model presented in Annex A of the present document,
which allows concluding whether the HDR-DSRC downlink, or the uplink, or both links are interfered. The
performance results for the various test configurations with a single interferer and multiple interferers, both conducted
in an anechoic chamber and in a real road environment, indicate that harmful interference is only on the HDR-DSRC
downlink.
ETSI

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5 ETSI TR 103 403 V1.1.1 (2017-06)

Coexistence scenarios were identified for HDR-DSRC, i.e. technical limits to mitigate harmful interference are:
• The ITS-SUs upper TX power limit is 14 dBm EIRP.
• The lower distance limit between a HDR-DSRC OBU and an ITS-M5 interferer transmitting with 23 dBm
EIRP is 5 m.
• The ITS-M5 repetition interval of 100 ms is not resulting in harmful interference.
Introduction
With the birth of communications in the 5 GHz bands [i.2], [i.3], [i.4] for Intelligent Transport Systems (ITS) on the
basis of the ITS station and communication architecture specified in [i.6] and [i.5] potential harmful interference caused
by ITS equipment installed in vehicles on Electronic Fee Collection (EFC) and Electronic Toll Collection (ETC)
installations (toll plazas) became obvious. Two major standardized Dedicated Short Range Communication (DSRC)
technologies are used in Europe and other regions for EFC/ETC and other road transport related services, i.e. the
CEN-DSRC technology standardized by CEN (also referred to as TTT-DSRC according to CEPT decision) and by
ETSI in the European harmonised multi part standard ETSI EN 300 674-2-1 [i.11], ETSI EN 300 674-2-2 [i.12], and the
High Data Rate - DSRC (HDR-DSRC) technology standardized by UNINFO in Italy and by ETSI ES 200 674-1 [i.1].
Both DSRC technologies operate in the same band at 5,8 GHz. Initial interference tests and simulations were performed
for MDR-DSRC [i.8], and resulted in mitigation techniques standardized in [i.7]. These mitigation techniques were
taken as basis for further investigations on HDR-DSRC.
The present document:
• complements [i.8] by presenting results of investigations on interference of 5,9 GHz ITS communications on
the HDR-DSRC systems;
• recommends mitigation techniques with reference to [i.7]; and
• suggests running of an ETSI plug test dedicated to HDR-DSRC.
ETSI

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6 ETSI TR 103 403 V1.1.1 (2017-06)

1 Scope
The present document reports about test executions and results of tests performed with equipment compliant with ETSI
ES 200 674-1 [i.1] (referred to as HDR-DSRC or CEN-DSRC) and equipment compliant with ETSI EN 302 663 [i.4]
operating in the 5 GHz frequency band (referred to as ITS-G5 or ITS-M5). The purposes of the tests are to identify
potential interference of ITS-G5 emissions on the HDR-DSRC communications used e.g. for electronic road tolling,
and the evaluation of mitigation techniques specified in ETSI TS 102 792 [i.7].
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 ES 200 674-1 (V2.4.1) (05-2013): "Intelligent Transport Systems (ITS); Road Transport and
Traffic Telematics (RTTT); Dedicated Short Range Communications (DSRC); Part 1: Technical
characteristics and test methods for High Data Rate (HDR) data transmission equipment operating
in the 5,8 GHz Industrial, Scientific and Medical (ISM) band".
[i.2] IEEE 802.11™ (2016): "IEEE Standard for Information technology - Telecommunications and
information exchange between systems local and metropolitan area networks - Specific
requirements - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)
Specifications".
[i.3] ISO 21215: "Intelligent transport systems -- Communications access for land mobiles (CALM) --
M5".
[i.4] ETSI EN 302 663 (V1.2.1) (07-2013): "Intelligent Transport Systems (ITS); Access layer
specification for Intelligent Transport Systems operating in the 5 GHz frequency band".
[i.5] ETSI EN 302 665 (V1.1.1) (09-2010): "Intelligent Transport Systems (ITS); Communications
Architecture".
[i.6] ISO 21217 (2014): "Intelligent transport systems -- Communications Access for Land Mobiles
(CALM) -- Architecture".
[i.7] ETSI TS 102 792 (V1.2.1) (06-2015): "Intelligent Transport Systems (ITS); Mitigation techniques
to avoid interference between European CEN Dedicated Short Range Communication (CEN
DSRC) equipment and Intelligent Transport Systems (ITS) operating in the 5 GHz frequency
range".
[i.8] ETSI TR 102 960 (V1.1.1) (11-2012): "Intelligent Transport Systems (ITS); Mitigation techniques
to avoid interference between European CEN Dedicated Short Range Communication (RTTT
DSRC) equipment and Intelligent Transport Systems (ITS) operating in the 5 GHz frequency
range; Evaluation of mitigation methods and techniques".
[i.9] Commsignia: "OB2-M/ITS-RS2-M User Manual"; version: V1.7.5-b12, 3 (March 2015).
®
[i.10] Narda Safety Test Solutions: "SRM 3006 Selective Radiation Meter Operating Manual".
ETSI

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7 ETSI TR 103 403 V1.1.1 (2017-06)

[i.11] ETSI EN 300 674-2-1 (V2.1.1) (11-2016): "Transport and Traffic Telematics (TTT); Dedicated
Short Range Communication (DSRC) transmission equipment (500 kbit/s / 250 kbit/s) operating in
the 5 795 MHz to 5 815 MHz frequency band; Part 2: Harmonised Standard covering the essential
requirements of article 3.2 of the Directive 2014/53/EU; Sub-part 1: Road Side Units (RSU)".
[i.12] ETSI EN 300 674-2-2 (V2.1.1) (11-2016): "Transport and Traffic Telematics (TTT); Dedicated
Short Range Communication (DSRC) transmission equipment (500 kbit/s / 250 kbit/s) operating in
the 5 795 MHz to 5 815 MHz frequency band; Part 2: Harmonised standard covering the essential
requirements of article 3.2 of Directive 2014/53/EU; Sub-part 2: On-Board Units (OBU)".
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in ETSI ES 200 674-1 [i.1] and the following
apply:
ITS-G5: access technology to be used in frequency bands dedicated for European Intelligent Transport System (ITS)
NOTE: Details of compliance are specified in ETSI EN 302 663 [i.4] and ISO 21215 [i.3].
ITS-M5: communications technology operating in the 5 GHz bands allocated for ITS compliant with IEEE 802.11 [i.2]
NOTE: Details of compliance are specified in ETSI EN 302 663 [i.4] and ISO 21215 [i.3].
3.2 Symbols
For the purposes of the present document, the symbols given in ETSI ES 200 674-1 [i.1] and the following apply:
f HDR DSRC downlink centre frequency
c
f ITS-M5 centre frequency
c,ITS
G Gain of the HDR-DSRC OBU antenna in bore-sight direction
OBU
G Gain of the HDR-DSRC RSU antenna in bore-sight direction
RSU
N Number of HDR-DSRC test signals (ECHO.request) in a test bundle
bundle
N Number of successfully received HDR-DSRC test signals (ECHO.response) in a test bundle
success
P Probability of lost HDR-DSRC test signals
loss
P Probability of an overlap of ITS test signal with interfered HDR-DSRC test signal
overlap
Probability of successfully received HDR-DSRC test signals
P
success
T Duration of interfered HDR-DSRC test signal
d1
T Duration of interfering ITS test signal
d2
T Duration of HDR-DSRC downlink test signal
d1d
T Duration of HDR-DSRC uplink test signal
d1u
T Repetition period of HDR-DSRC test signal
p1
T Repetition period of ITS test signal
p2
3.3 Abbreviations
For the purposes of the present document, the abbreviations given in ETSI ES 200 674-1 [i.1] and the following apply:
AM Amplitude Modulation
CEN European Committee for Standardization
CEPT Conférence Européenne des Administrations des Postes et des Télécommunications
CTI Centre for Testing and Interoperability
DC Direct Current
DSRC Dedicated Short Range Communication
EFC Electronic Fee Collection
EIRP Effective Isotropic Radiated Power
ETC Electronic Toll Collection
ETSI

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8 ETSI TR 103 403 V1.1.1 (2017-06)

FSK Frequency Shift Keying
HDR High Data Rate
HDR-DSRC High Data Rate - DSRC
ISO International Organization for Standardization
ITS Intelligent Transport Systems
ITS-SU ITS Station Unit
ITS-SU ITS Station Unit
JRC Joint Research Centre (of the European Commission)
LPDU Link Protocol Data Unit
MAC Medium Access Control
MDR-DSRC Medium Data Rate-DSRC
MIB Management Information Base
OBU On Board Unit
OCB Outside the Context of a BSS
OFDM Orthogonal Frequency Division Multiplexing
PSK Phase Shift Keying
RF Radio Frequency
RSU Road Side Unit
SRM Selective Radiation Meter
TTT DSRC Traffic Transport Telematics DSRC
TTT Transport and Traffic Telematics
TX Transmit
4 HDR-DSRC
4.1 Operational characteristics
Typical HDR-DSRC EFC/ETC installations are:
• Free-flow tolling installations with up to about 6 parallel lanes (typical 3 to 4 lanes in each traffic direction).
• Toll plazas with automatic barriers with up to about 40 parallel lanes (typical around 10 to 20 lanes in each
traffic direction).
The geometrical coordinate system of HDR-DSRC installations used in the present document is depicted in Figure 1
and Figure 2.

Figure 1: HDR-DSRC installation - top view
ETSI

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9 ETSI TR 103 403 V1.1.1 (2017-06)


Figure 2: HDR-DSRC installation - side view
The position {x=0, y=0, z=0} is the intersection of the main beam of the HDR-DSRC RSU antenna with the lane. The
centre of the HDR-DSRC RSU antenna is at the position {x=x =0, y=y , z=z }.The main beam direction of the
RSU RSU RSU
Θ= Θ . Limits of radiated power as a function of Θ are presented in
HDR-DSRC RSU antenna is given by the angle
RSU,bs
Table 1. The position of a HDR-DSRC OBU (not shown in the above figures) is {x=x , y=y , z=z }.
OBU OBU OBU
A typical installation of HDR-DSRC RSUs is presented in Figure 3. The angle Θ is very small and thus the hot
RSU,bs
spot on the lane is very limited in length (y-axis in Figures 1 and 2).

Figure 3: Typical HDR-DSRC RSU installation
ETSI

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10 ETSI TR 103 403 V1.1.1 (2017-06)

4.2 Technical characteristics
4.2.1 Roadside unit
Characteristics of HDR-DSRC RSUs are presented in Table 1.
Table 1: Parameters of a typical HDR-DSRC RSU
HDR-DSRC RSU RF parameter Value Comment
Receiver bandwidth (0,7 MHz + 0,288 MHz) FSK frequency deviation (0,7 MHz) plus
× 2 = 1,976 MHz symbol rate bandwidth considering the
Manchester coding scheme and the uplink
symbol rate of 288 kbit/s.
Receiver sensitivity ≤ -92 dBm
Receiver centre frequency f ± 10,7 MHz
c
Antenna bore sight direction, see Figure 2 Θ Depends on installation.
RSU,bs
Antenna polarization Vertical linear
Antenna cross polarization > 20 dB In boresight.
≥ 10 dB -3 dB area.
Transmitter bandwidth f ± 1,842 MHz Considering the Manchester coding
c
scheme and the symbol rate of 1 842 kbit/s.
Transmitter angular EIRP mask ≤ +39 dBm 0° ≤ Θ ≤ 30°.
Θ is the angle relative to a vector perpendicular to ≤ +33 dBm 30° < Θ ≤ 50°.
the road surface, pointing downwards, see Figure 2
≤ +23 dBm 50° < Θ ≤ 70°.
≤ +15 dBm Θ > 70°.
Transmitter carrier centre frequency f 5,8 GHz, 5,81 GHz is an optional centre frequency
c
5,81 GHz potentially used in the future for free-flow
tolling.
Downlink modulation scheme ASK-OOK
Downlink data coding Manchester
Downlink bit rate 921 kbit/s
Protection criterion (S/I) - co-channel rejection limit 6 dB FSK, 2-PSK.

ETSI

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11 ETSI TR 103 403 V1.1.1 (2017-06)

4.2.2 Onboard unit
Characteristics of HDR-DSRC OBUs are presented in Table 2.
Table 2: Parameters of a typical HDR-DSRC OBU
HDR-DSRC OBU RF parameter Value Comment
Wake-up sensitivity ≤ -40 dBm Wake-up on a defined pattern.
Receiver sensitivity ≤ -40 dBm Measured within the 35° border of a cone
symmetrically around boresight direction as
declared by the manufacturer.
Antenna bore sight direction not directly specified Depends on installation in vehicle.
in [i.1]
Antenna cross polarization > 10 dB In boresight.
≥ 6 dB -3 dB area.
≤ G - 1,5 dB
Antenna gain outside HDR-DSRC OBU
OBU
active angle range
Antenna polarization either vertical linear or
left-hand circular
Vehicle windscreen loss 3 dB Depends on installation in vehicle.
Transmitter bandwidth f ± (10,7 MHz + 0,7 MHz See uplink modulation scheme, data
c
encoding, and data rate. Same data sent
+ 0,288 MHz) =
simultaneously in both sidebands.
f ± 11,688 MHz
c
Transmitter maximum output power level, < -14 dBm Measured at the 35° border of a cone
Single-sideband EIRP symmetrically around boresight direction,
i.e. at the border of the -3 dB area.
Transmitter sub carrier centre frequencies f ± 10,7 MHz Sub-carrier @ 10,7 MHz FSK modulated with
c
two tones ±0,7 MHz:
Binary FSK (±700 kHz) on sub-carrier at
10,7 MHz.
Uplink modulation scheme AM On carrier.
Uplink data coding Manchester
Uplink bit rate 144 kbit/s
Same data are sent simultaneously in both
sidebands

Figure 4 shows a worst case theoretical HDR-DSRC OBU antenna pattern compliant with the definition of the 3 dB
area in ETSI ES 200 674-1 [i.1]. The figure is normalized to the antenna gain in bore-sight direction and shows the
square-law attenuation as function of the opening angle Θ of the cone in the range zero degree (bore-sight) to 90°.

Figure 4: Worst case theoretical HDR-DSRC OBU
antenna pattern compliant with ETSI ES 200 674-1 [i.1]
ETSI

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12 ETSI TR 103 403 V1.1.1 (2017-06)

4.3 Protocol characteristics
All transmissions are in frames. A frame consists of a one octet start flag, a Link Protocol Data Unit (LPDU) field of
variable length, a two octet frame check sequence, and a one octet stop flag. The total length of a frame in downlink and
uplink communications is limited to 64 octets plus a number of zero bits inserted dependent on the data in order to
avoid appearance of the flag pattern in between the start flag and stop flag.
In downlink communications, a wake-up signal with maximum duration of 2,36 ms may be sent by an
HDR-DSRC RSU.
In the downlink and the uplink, communications will start with a preamble, followed by the frame described above. The
size of a preamble is between 16 bits and 32 bits; this corresponds to a duration of 111 µs up to 222 µs at 144 kbit/s in
the uplink, and 17,4 µs up to 34,8 µs at 921 kbit/s in the downlink.
The maximum downlink transmission time of a frame T (without wake-up header and preamble) is 590 µs. If an
...