ETSI TR 103 766 V1.1.1 (2021-09)

Intelligent Transport Systems (ITS); Pre-standardization study on co-channel co-existence between IEEETM- and 3GPP- based ITS technologies in the 5 855 MHz-5 925 MHz frequency band

DTR/ERM-TG37-273

General Information

• Status: Not Published
• Technical Committee: ERM TG37 - ERM Intelligent Transport Systems
• Current Stage: 12 - Completion
• Due Date: 03-Sep-2021
• Completion Date: 15-Sep-2021

Standards Content (Sample)

TECHNICAL REPORT
Intelligent Transport Systems (ITS);
Pre-standardization study on co-channel co-existence between
IEEE- and 3GPP- based ITS technologies in
the 5 855 MHz - 5 925 MHz frequency band


2 ETSI TR 103 766 V1.1.1 (2021-09)

Reference
DTR/ERM-TG37-273
Keywords
coexistence, ITS, radio
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ETSI
3 ETSI TR 103 766 V1.1.1 (2021-09)
Contents
Intellectual Property Rights . 6
Foreword . 6
Modal verbs terminology . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 7
3 Definition of terms, symbols and abbreviations . 9
3.1 Terms . 9
3.2 Symbols . 9
3.3 Abbreviations . 9
4 Technical description of road ITS technologies . 11
4.1 Introduction . 11
4.2 ITS-G5 . 12
4.2.1 Introduction. 12
4.2.2 Physical layer . 13
4.2.3 Medium access control . 14
4.2.3.1 Introduction . 14
4.2.3.2 Backoff procedure . 14
4.2.3.3 Medium access control . 14
4.2.3.4 EDCA parameters, AC and UP . 15
4.3 LTE-V2X . 17
4.3.1 Introduction. 17
4.3.2 Physical layer . 17
4.3.3 Medium access control . 18
4.3.3.1 Introduction . 18
4.3.3.2 Sensing based semi-persistent scheduling . 18
4.3.3.3 Hybrid automatic request . 20
4.4 New road ITS technologies . 20
4.4.1 Introduction. 20
4.4.2 IEEE 802.11bd . 20
4.4.3 5G-NR V2X . 20
5 Problem statement . 21
5.1 Introduction . 21
5.2 Overlapping message transmissions . 22
5.2.1 The last symbol gap problem . 22
5.2.2 ITS-G5 cut off by LTE-V2X resuming transmission . 24
5.3 Basic principles for co-channel co-existence solutions . 25
5.3.1 Fair sharing of time resources depending on relative traffic load . 25
5.3.2 Distributed channel access management . 25
5.3.3 Orthogonality of channel access . 25
5.3.4 Deterministic timing . 25
5.3.5 Guard time between transmission intervals . 26
6 Co-channel co-existence methods . 26
6.1 Introduction . 26
6.1.1 Background . 26
6.1.2 Sharing in the time domain . 26
6.1.3 Limitations of sharing in the time domain . 27
6.1.4 Presumptions. 28
6.1.4.1 Half duplex constraint . 28
6.1.4.2 Synchronization . 29
6.2 Configuration of time slot boundary . 29
6.2.1 Static, semi-static and dynamic . 29
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4 ETSI TR 103 766 V1.1.1 (2021-09)
6.2.2 Dynamic local configuration of time slot sizes . 29
6.2.3 Dynamic global configuration of time slot sizes . 30
6.3 Co-channel co-existence methods . 32
6.3.1 Method A: Classic TDM method . 32
6.3.1.1 Introduction . 32
6.3.1.2 Semi-static TDM pattern update . 33
6.3.1.3 Dynamic TDM pattern update. 33
6.3.1.4 Alternative method to detect LTE-V2X transmission boundaries . 34
6.3.1.5 Enhancement to Method A . 34
6.3.2 Method B: Energy signals . 36
6.3.2.1 Introduction . 36
6.3.2.2 Energy signal type 1 . 36
6.3.2.3 Energy signal type 2 . 36
6.3.2.4 Energy signal type 3 . 37
6.3.3 Method C: ITS-G5 PHY header insertion . 37
6.3.3.1 Introduction . 37
6.3.3.2 Option 1: Single LTE-V2X transmission protection . 38
6.3.3.3 Option 2: Multiple LTE-V2X transmission protection with enhancement . 38
6.3.4 Method D: Reservation messages . 39
6.3.5 Method E: Combination of ITS-G5 PHY header insertion and reservation messages . 39
6.3.6 Method F: LTE-V2X applying IEEE 802.11 NAV setting . 40
6.3.6.1 Introduction . 40
6.3.6.2 CTS-to-Self as NAV setting signal . 41
6.3.6.3 Selection of an LTE-V2X station to issue the NAV setting signal . 43
6.3.6.4 New ITS-G5 station entering NAV setting range . 44
6.3.7 Method G: Load-based approach . 45
7 Evaluation . 46
7.1 Key performance indicators . 46
7.1.1 Packet reception ratio. 46
7.1.2 Data age . 46
7.1.3 End-to-end delay . 47
7.1.4 Inter-packet gap . 47
7.2 Simulation framework . 48
7.2.1 Introduction. 48
7.2.2 Road traffic scenarios . 48
7.2.2.1 Introduction . 48
7.2.2.2 Urban scenario . 48
7.2.2.3 Highway scenario . 49
7.2.2.3.1 Fast highway scenario . 49
7.2.2.3.2 Slow highway scenario . 50
7.2.2.4 High-priority DENM generation scenarios . 51
7.2.2.4.1 Introduction . 51
7.2.2.4.2 Fast highway . 51
7.2.2.4.3 Slow highway . 51
7.2.2.4.4 Urban . 52
7.2.2.5 Vehicle Drop . 52
7.2.2.6 Number of vehicles and traffic mixes for numerical simulations. 52
7.2.3 Channel model . 53
7.2.4 Data traffic generation . 54
7.2.4.1 Message size . 54
7.2.4.2 Time intervals . 54
7.3 Results . 55
7.3.1 Observations . 55
7.3.1.1 ITS-G5 channel busy ratio levels . 55
7.3.1.2 Superframe sizes and time slot configurations . 56
7.3.2 Simulations . 56
7.3.2.1 Parameter settings . 56
7.3.2.2 Successful reception of messages . 58
7.3.2.3 Baseline performance . 59
7.3.2.3.1 Introduction . 59
7.3.2.3.2 Configuration 1 . 59
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5 ETSI TR 103 766 V1.1.1 (2021-09)
7.3.2.3.3 Configuration 2 . 61
7.3.2.3.4 Wrap up . 63
7.3.2.4 Method A . 63
7.3.2.4.1 Enhancement to Method A . 63
7.3.2.4.2 Mismatch between TDM pattern and technology mix . 67
7.3.2.4.3 Semi-static Method A . 68
7.3.2.4.4 Wrap up . 70
7.3.2.5 Method C . 71
7.3.2.5.1 Ideal TDM pattern . 71
7.3.2.5.2 Deriving TDM pattern from local measurements . 72
7.3.2.5.3 Wrap up . 73
7.3.2.6 Comparison several methods . 73
7.3.2.7 Co-channel co-existence with legacy ITS-G5 stations . 78
7.3.2.8 Summary simulation results . 82
8 Conclusions . 84
Annex A: Detailed description of the ITS-G5 header insertion . 86
A.1 Introduction . 86
A.2 Option 1 - configuration of L-SIG information . 87
A.3 Option 2 - configuration of L-SIG information . 88
A.4 Resampling of ITS-G5 header to LTE native rate . 89
A.5 Transmit power for the ITS-G5 header . 89
A.6 Multiple LTE-V2X stations transmitting ITS-G5 headers in the same subframe . 89
A.7 Options of Method C . 90
A.7.1 Option 1 . 90
A.7.2 Option 2 . 90
Annex B: Collected statistics for CAMs . 92
Annex C: Eclipse Sumo™ generated mobility traces . 95
Annex D: Technology detection . 96
D.1 Introduction . 96
D.2 ITS-G5 detecting LTE-V2X . 96
D.2.1 Cyclic prefix . 96
D.2.2 Change CCA threshold . 96
D.2.3 LTE-V2X transmits energy signals . 96
D.2.4 LTE-V2X transmits ITS-G5 PHY header . 96
D.3 LTE-V2X CBR assessment . 97
Annex E: Details about the LOS channel models . 99
Annex F: ITS-G5 stations with time synchronization . 101
Annex G: Derivation of the traffic mix mismatch for numerical simulations . 102
Annex H: Time slot durations . 105
History . 107

ETSI
6 ETSI TR 103 766 V1.1.1 (2021-09)
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Foreword
This Technical Report (TR) has been produced by ETSI Technical Committee Electromagnetic compatibility and Radio
spectrum Matters (ERM).
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.

ETSI
7 ETSI TR 103 766 V1.1.1 (2021-09)
1 Scope
The present document carries out studies on the feasibility of co-channel co-existence between ITS-G5 and LTE-V2X
technologies based on solutions presented to CEPT. It defines methodologies and metrics required for performing the
studies and evaluating the performance of the solutions studied. To find co-channel co-existence methods, which enable
both technologies to use the same frequency channel in the same geographical area, while meeting the metrics defined.
The present document classifies co-channel co-existence methods depending on the observed metrics.
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 302 665 (V1.1.1) (09-2010): "Intelligent Transport Systems (ITS); Communications
Architecture".
[i.2] ETSI EN 302 663 (V1.3.1) (01-2020): "Intelligent Transport Systems (ITS); ITS-G5 Access layer
specification for Intelligent Transport Systems operating in the 5 GHz frequency band".
[i.3] IEEE Std 802.11™-2020: "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.4] IEEE/ISO/IEC 8802-2-1998: "Information technology -- Telecommunications and information
exchange between systems -- Local and metropolitan area networks -- Specific requirements --
Part 2: Logical Link Control".
[i.5] IEEE 802.11e™-2005: "IEEE Standard for Information technology - Local and metropolitan area
networks - Specific requirements - Part 11: Wireless LAN Medium Access Control (MAC) and
Physical Layer (PHY) Specifications - Amendment: Medium Access Method (MAC) Quality of
Service Enhancements".
[i.6] ANSI/IEEE Std 802.1D™-1998: "IEEE Standard for Information technology -
Telecommunications and information exchange between systems - Local and metropolitan area
networks - Common specifications - Part 3: Media Access Control (MAC) Bridges".
[i.7] ETSI EN 303 613 (V1.1.1) (01-2020): "Intelligent Transport Systems (ITS); LTE-V2X Access
layer specification for Intelligent Transport Systems operating in the 5 GHz frequency band".
[i.8] ETSI TS 136 213 (V15.9.0): "LTE; Evolved Universal Terrestrial Radio Access (E-UTRA);
Physical layer procedures (3GPP TS 36.213 version 15.9.0 Release 15)".
[i.9] ETSI TS 136 211 (V14.3.0): "LTE; Evolved Universal Terrestrial Radio Access (E-UTRA);
Physical channels and modulation (3GPP TS 36.211 version 14.3.0 Release 14)".
ETSI
8 ETSI TR 103 766 V1.1.1 (2021-09)
[i.10] ETSI TS 136 300 (V14.3.0): "LTE; Evolved Universal Terrestrial Radio Access (E-UTRA) and
Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2
(3GPP TS 36.300 version 14.3.0 Release 14)".
[i.11] ETSI TS 136 321 (V14.3.0): "LTE; Evolved Universal Terrestrial Radio Access (E-UTRA);
Medium Access Control (MAC) protocol specification (3GPP TS 36.321 version 14.3.0
Release 14)".
[i.12] ETSI TS 136 101 (V14.4.0): "LTE; Evolved Universal Terrestrial Radio Access (E-UTRA); User
Equipment (UE) radio transmission and reception (3GPP TS 36.101 version 14.4.0 Release 14)".
[i.13] 3GPP TR 36.885: "Study on LTE-based V2X services" (V14.0.0, Release 14)", June 2016.
[i.14] F. Berens, V. Martinez, and K. Moerman: "Survey on CAM statistics," presented at ETSI ITS
workshop 2019.
NOTE: Available online:
https://docbox.etsi.org/Workshop/2019/201903_ITSWS/SESSION03/NXP_Moerman.pdf.
[i.15] CAR2CAR Communication Consortium: "Survey on ITS-G5 CAM statistics," 2018.
NOTE: Available online: https://www.car-2-
car.org/fileadmin/documents/General_Documents/C2CCC_TR_2052_Survey_on_CAM_statistics.pdf.
[i.16] ETSI EN 302 637-3 (V1.3.1) (04-2019): "Intelligent Transport Systems (ITS); Vehicular
Communications; Basic Set of Applications; Part 3: Specifications of Decentralized
Environmental Notification Basic Service".
[i.17] ETSI EN 302 637-2 (V1.4.1) (04-2019): "Intelligent Transport Systems (ITS); Vehicular
Communications; Basic Set of Applications; Part 2: Specification of Cooperative Awareness Basic
Service".
[i.18] 3GPP TR 36.843: "Study on LTE Device to Device Proximity Services; Radio Aspects (V12.0.1,
Release 12)" March 2014.
[i.19] Report Recommendation ITU-R M.2135-1 (2009): "Guidelines for evaluation of radio interface
technologies for IMT-Advanced".
[i.20] T.S. Rappaport: "Wireless Communications: Principles and Practice", second edition, Prentice
Hall. .
[i.21] C. Sommer, and F. Dressler: "Using the right two-ray model? A measurement-based evaluation of
th
PHY models in VANETs", in 17 ACM MobiCom, Poster Session, Las Vegas, NV,
September 2011.
[i.22] Recommendation ITU-R P.1411-10 (08-2019): "Propagation data and predicition methods for the
planning of short-range outdoor radiocommunication systems and radio local area networks in the
frequency range 300 MHz to 100 GHz".
[i.23] ECC Report 68: "Compatibility studies in the band 5725-5875 MHz between fixed wireless access
(FWA) and other systems," June 2005.
[i.24] ECC Report 250: "Compatibility studies between TTT/DSRC in the band 5805-5815 MHz and
other systems," April 2016.
[i.25] ETSI TS 103 574 (V1.1.1) (11-2018): "Intelligent Transport Systems (ITS); Congestion Control
Mechanisms for C-V2X PC5 interface; Access layer part".
[i.26] ETSI TS 102 687 (V1.2.1) (04-2018): "Intelligent Transport Systems (ITS); Decentralized
Congestion Control Mechanisms for Intelligent Transport Systems operating in the 5 GHz range;
Access layer part".
[i.27] IEEE Std 1609.4™-2016: "IEEE Standard for Wireless Access in Vehicular Environments
(WAVE) - Multi-Channel Operation".
ETSI
9 ETSI TR 103 766 V1.1.1 (2021-09)
[i.28] ETSI TS 103 723 (V1.2.1) (11-2020): "Intelligent Transport Systems (ITS); Profile for LTE-V2X
Direct Communication".
[i.29] 3GPP TS 36.101: "Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE)
radio transmission and reception (V16.4.0, Release 16)", December 2019.
[i.30] TGbd: "Project Authorization Request (PAR)", IEEE 802.11-18/0861r9.
NOTE: Available at https://mentor.ieee.org/802.11/dcn/18/11-18-0861-09-0ngv-ieee-802-11-ngv-sg-proposed-
par.docx.
[i.31] G. Naik, B. Choudhury and J. Park: "IEEE 802.11bd & 5G NR V2X: Evolution of Radio Access
Technologies for V2X Communications," in IEEE Access, 2019. doi:
10.1109/ACCESS.2019.2919489.
[i.32] M. H. C. Garcia et al.: "A Tutorial on 5G NR V2X Communications," in IEEE Communications
Surveys & Tutorials, 2021. doi: 10.1109/COMST.2021.305701.
[i.33] ETSI TS 136 133 (V14.17.0): "LTE; Evolved Universal Terrestrial Radio Access (E-UTRA);
Requirements for support of radio resource management (3GPP TS 36.133 version 14.7.0
Release 14)".
[i.34] ETSI EN 302 571 (V2.1.1): "Intelligent Transport Systems (ITS); Radiocommunications
equipment operating in the 5 855 MHz to 5 925 MHz frequency band; Harmonised Standard
covering the essential requirements of article 3.2 of Directive 2014/53/EU".
[i.35] ETSI TS 103 613: "Intelligent Transport Systems (ITS); Access layer specification for Intelligent
Transport Systems using LTE Vehicle to everything communication in the 5,9 GHz frequency
band".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
subframe: time interval equal to 1 ms
NOTE: This equals the "subframe duration" as defined in ETSI TS 136 211 [i.9].
superframe: consists of two time slots
time slot: integer multiple of consecutive subframes
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AC Access Category
ACK ACKnowledgement
AGC Automatic Gain Control
AIFS Arbitration InterFrame Space
AIFSN AIFS Number
AP Access Point
ARQ Automatic Repeat reQuest
BE Best Effort
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10 ETSI TR 103 766 V1.1.1 (2021-09)
BK Background
BPSK Binary Phase Shift Keying
BS Base Station
BSS Basic Service Set
BSSID BSS identifier
C2C-CC CAR2CAR Communication Consortium
CAM Cooperative Awareness Message
CBR Channel Busy Ratio
CCA Clear Channel Assement
CDF Cumulative Distribution Function
CEN Comité Européen de Normalisation
CP Cyclic Prefix
CRC Cyclic Redundancy Check
CSI Channel Sidelink Information
CSMA/CA Carrier Sense Multiple Access/Collision Avoidance
CSR Candidate Single-subframe Resources
CTS Clear To Send
CW Contention Window
DA Data Age
DCC Decentralized Congestion Control
DCF Distributed Coordination Function
DENM Decentralized Environmental Notification Message
DIFS Distributed InterFrame Space
DL Data Link Layer
DMRS DeModulation Reference Signals
DSRC Dedicated Short Range Communication
EDCA Enhanced Distributed Channel Access
EE Excellent Effort
EED End-to-End Delay
ES Energy Signals
EVM Error Vector Magnitude
FCS Frame Check Sequence
GNSS Global Navigation Satellite System
HARQ Hybrid Automatic ReQuest
IBSS Independent BSS
IN Interface
IPG Inter-Packet Gap
IQ In-phase Quadrature phase
ITS Intelligent Transport Systems
ITS-S ITS Station
KPI Key Performance Indicator
LDPC Low Density Parity Check
LLC Logical Link Control
LOS Line-Of-Sight
LTE Long Term Evolution
LTF Long Training Field
LUT LookUp Table
MAC Medium Access Control
MCS Modulation and Coding Scheme
MIB Management Information Base
MPDU MAC Protocol Data Unit
MSPS Mega Symbols Per Second
NAV Network Allocation Vector
NC Network Control
NLOS Non-Line-Of-Sight
NR New Radio
OBU OnBoard Unit
OFDM Orthogonal Frequency Division Multiplexing
OSI Open System Interconnect
PDU Protocol Data Unit
PER Packet Error Rate
PHY Physical Layer
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11 ETSI TR 103 766 V1.1.1 (2021-09)
PLCP Physical Layer Convergence Procedure
PPDU PLCP Protocol Data Unit
PPS Parts Per Second
PRR Packet Reception Ratio
PSCCH Physical Sidelink Control Channels
PSDU PLCP Service Data Unit
PSSCH Physical Sidelink Shared Channels
QAM Quadrature Amplitude Modulation
QoS Quality of Service
QPSK Quadrature Phase Shift Keying
RA Receive Address
RB Resource Block
RSRP Reference Signal Received Power
RSSI Received Signal Strength Indicator
RSU RoadSide Unit
RTS Requestion To Send
RX Receiver
SC-FDMA Single-Carrier Frequency Division Multiple Access
SCI Sidelink Control Information
SDR Software Defined Radio
SIFS Short InterFrame Space
SINR Signal to Interference and Noise Ratio
SPS Semi-Persistent Scheduling
STF Short Training Field
SUMO Simulation of Urban Mobility
TB Transport Block
TDM Time Division Multiplexing
TDMA Time Division Multiple Access
TL Time Length
TTI Transmission Time Interval
TX Transmitter
UP User Priority
VI Video
VO Voice
4 Technical description of road ITS technologies
4.1 Introduction
The two studied road ITS technologies herein are ITS-G5 and LTE-V2X (3GPP Release 14) [i.2]. The technologies
represent the access layer of the ITS communications architecture, see Figure 4.1, outlined in ETSI EN 302 665 [i.1].
The access layer consists of the physical layer (PHY) and the data link layer (DL) of the OSI model.
ETSI
12 ETSI TR 103 766 V1.1.1 (2021-09)

Figure 4.1: The ITS stations reference architecture [i.1]
4.2 ITS-G5
4.2.1 Introduction
ITS-G5 is outlined in ETSI EN 302 663 [i.2] describing the access layer of the ITS station reference architecture. The
ITS-G5 access layer consists of:
• IEEE 802.11-2020 [i.3] operating outside the context of a basic service set (enabled by setting the MIB
parameter dot11OCBEnabled to true).
• IEEE 802.2 Logical Link Control (LLC) [i.4].
IEEE 802.11-2020 outlines the PHY and the Medium Access Control (MAC) protocol used for vehicular ad hoc
networking in ITS-G5. The PHY is based on Orthogonal Frequency Division Multiplexing (OFDM) and the MAC is
using the Enhanced Distributed Channel Access (EDCA) functionality, see Clause 4.2.2 and Clause 4.2.3 for more
technical details.
The IEEE 802.11-2020 [i.3] standard contains two basic network topologies: the infrastructure BSS and the independent
BSS (IBSS). The former contains an Access Point (AP) and data traffic usually takes a detour through the AP even
though two nodes are closely co-located. The IBSS is a set of nodes communicating directly with each other and this is
also called ad hoc or peer-to-peer network. Both these topologies are aimed for nomadic devices and synchronization is
required between nodes performed via beacons. Further, they are identified with a unique BSSID. Association and
authentication are required in infrastructure BSS whereas in IBSS association is not used and communication can take
place in an unauthenticated mode. With the introduction of 802.11p a new capability of the 802.11 is introduced,
namely communication outside the context of a BSS, see Clause 4.3.17 of IEEE 802.11-2020 [i.3]. The communication
outside of a BSS is enabled by setting the MIB variable dot11OCBActivated to true. In this mode authentication,
association and security between nodes are disabled at the MAC sublayer. This implies that active and passive scanning
of BSS and IBSS are disabled. The scanning on frequency channels for the node to join an existing network is no longer
enabled. Therefore, the implementation when the MIB variable is set to dot11OCBActivated true in the vehicular
environment requires predetermined frequency channels to be set in the management.
NOTE: The possibility to communicate outside the context of a BSS for vehicular communication was introduced
in the IEEE 802.11p amendment. IEEE 802.11p was published in 2010 and it was enrolled into 802.11 in
2012, at which time the 802.11p amendment was classified as superseded. H
...