ETSI TS 103 831 V2.2.1 (2024-04)

Intelligent Transport Systems (ITS); Vehicular Communications; Basic Set of Applications; Decentralized Environmental Notification Service; Release 2

RTS/ITS-001962

General Information

• Status: Not Published
• Technical Committee: ITS WG1 - Application Requirements and Services
• Current Stage: 12 - Citation in the OJ (auto-insert)
• Due Date: 24-Apr-2024
• Completion Date: 18-Apr-2024
• Mandate: M/453

Standards Content (Sample)

TECHNICAL SPECIFICATION
Intelligent Transport Systems (ITS);
Vehicular Communications;
Basic Set of Applications;
Decentralized Environmental Notification Service;
Release 2
2 ETSI TS 103 831 V2.2.1 (2024-04)

Reference
RTS/ITS-001962
Keywords
application, ITS, safety, service, transport

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All rights reserved.
ETSI
3 ETSI TS 103 831 V2.2.1 (2024-04)
Contents
Intellectual Property Rights . 6
Foreword . 6
Modal verbs terminology . 6
Introduction . 6
1 Scope . 8
2 References . 8
2.1 Normative references . 8
2.2 Informative references . 9
3 Definition of terms, symbols and abbreviations . 9
3.1 Terms . 9
3.2 Symbols . 10
3.3 Abbreviations . 11
4 DEN service introduction . 12
4.1 Background . 12
4.2 Services provided by the DEN service . 13
5 DEN service functional specification . 15
5.1 Introduction . 15
5.2 DEN service in the ITS architecture . 15
5.3 DEN service functional architecture. 16
5.4 Interfaces of the DEN service . 17
5.4.1 Interfaces to the ITS application layer . 17
5.4.1.1 Introduction . 17
5.4.1.2 Data passed via interface IF.DEN.1 for the request type AppDENM_trigger . 18
5.4.1.3 Data passed via interface IF.DEN.1 for the request type AppDENM_update . 19
5.4.1.4 Data passed via interface IF.DEN.1 for the request type AppDENM_termination . 20
5.4.1.5 Data passed via interface IF.DEN.2 for received DENM . 21
5.4.1.6 Methods for data exchanges between DEN service and ITS application layer . 21
5.4.2 Interface to MCO_FAC . 22
5.4.3 Interface to the ITS networking & transport layer . 22
5.4.3.1 General requirements . 22
5.4.3.2 Interface to the GeoNetworking/BTP stack . 23
5.4.3.3 Interface to the IPv6 stack and the combined IPv6/GeoNetworking stack . 24
5.4.4 Interface to the ITS management entity . 24
5.4.5 Interface to the ITS security entity . 24
6 DENM dissemination requirements . 24
6.1 DENM dissemination concepts . 24
6.1.1 Event identification . 24
6.1.1.1 actionId . 24
6.1.1.2 stationId update and actionId management . 25
6.1.2 Trigger, update, repetition and termination of DENM. 25
6.1.2.1 DENM trigger . 25
6.1.2.2 DENM update . 25
6.1.2.3 DENM repetition . 25
6.1.2.4 DENM termination. 26
6.1.3 Geographic location information . 27
6.1.3.1 Awareness area . 27
6.1.3.2 Relevance zone . 28
6.1.3.3 Detection zone . 29
6.1.3.4 Destination area . 29
6.1.4 DENM forwarding . 30
6.1.4.1 Packet centric forwarding . 30
6.1.4.2 Keep-alive forwarding . 30
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4 ETSI TS 103 831 V2.2.1 (2024-04)
6.2 DENM dissemination constraints . 31
6.2.1 General confidence constraints . 31
6.2.2 General security constraints . 31
6.2.2.1 Introduction . 31
6.2.2.2 Service Specific Permissions (SSP) . 31
6.2.3 General priority constraints. 34
7 DENM specification . 34
7.1 DENM structure . 34
7.1.1 General structure of a DENM . 34
7.1.2 ITS PDU header . 35
7.1.3 DENM Management container . 35
7.1.4 DENM Situation container . 36
7.1.5 DENM Location container . 36
7.1.6 DENM À La Carte container . 38
7.2 DENM format specification . 40
8 Protocol operation of the DEN service . 40
8.1 Introduction . 40
8.2 Originating ITS-S operation . 40
8.2.1 Protocol data setting rules . 40
8.2.1.1 General requirements . 40
8.2.1.2 actionId . 40
8.2.1.3 referenceTime . 41
8.2.1.4 termination . 41
8.2.1.5 T_O_Validity, T_RepetitionDuration and T_Repetition . 41
8.2.1.6 Originating ITS-S message table . 42
8.2.2 General protocol operation . 42
8.2.3 Exception handling . 49
8.2.3.1 General requirements . 49
8.2.3.2 DENM generation exception . 49
8.2.3.3 actionId non-existence exception . 49
8.2.3.4 Time operation exception . 49
8.3 Forwarding ITS-S operation . 49
8.3.1 Introduction. 49
8.3.2 Protocol data setting rules . 49
8.3.2.1 General requirements . 49
8.3.2.2 actionId . 50
8.3.2.3 referenceTime . 50
8.3.2.4 termination . 50
8.3.2.5 T_F_Validity and T_Forwarding . 50
8.3.2.6 Forwarding ITS-S message table . 50
8.3.2.7 DENM regeneration . 51
8.3.3 General protocol operation . 51
8.3.4 Exception handling . 53
8.3.4.1 General requirements . 53
8.3.4.2 DENM generation exception . 53
8.4 Receiving ITS-S operation . 54
8.4.1 Protocol data setting rules . 54
8.4.1.1 General requirements . 54
8.4.1.2 actionId . 54
8.4.1.3 referenceTime . 54
8.4.1.4 termination . 54
8.4.1.5 T_R_Validity . 54
8.4.1.6 Receiving ITS-S message table . 54
8.4.2 General protocol operation . 55
8.4.3 Exception handling . 57
8.4.3.1 General requirements . 57
8.4.3.2 DENM decoding exception . 57
Annex A (normative): ASN.1 module . 58
Annex B (informative): Specification of DENM in readable format . 59
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5 ETSI TS 103 831 V2.2.1 (2024-04)
Annex C (informative): Road configuration description . 60
C.1 Introduction . 60
C.2 Technical solution and scope of usage . 60
C.3 Technical solution description . 61
C.3.1 General definitions . 61
C.3.2 Rationales . 63
C.3.2.0 Introduction. 63
C.3.2.1 Connected and included traces and eventZone . 63
C.3.2.2 Road configuration descriptions for both driving directions . 65
C.3.2.3 Road configuration descriptions referring to MAPEM messages . 65
C.3.2.4 Lane numbering . 66
C.3.2.4 Road configuration Confidence . 66
History . 67

ETSI
6 ETSI TS 103 831 V2.2.1 (2024-04)
Intellectual Property Rights
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Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Intelligent Transport Systems
(ITS).
Modal verbs terminology
In the present document "shall", "shall not", "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.
Introduction
The DEN service is an application support functionality facility at the facilities layer. It generates, manages and
processes the Decentralized Environmental Notification Message (DENM). The generation of a DENM is triggered by
an ITS-S application. A DENM contains information related to a road hazard or an abnormal traffic condition, such as
its type and its position. The DEN service delivers the DENM as payload to the ITS networking & transport layer for
the message dissemination. Typically for an ITS application, a DENM is disseminated to ITS-Ss that are located in a
geographic area through communications among ITS stations. At the receiving side, the DEN service of an receiving
ITS-S processes the received DENM and provides the DENM content to an ITS-S application. This ITS-S application
may present the information to the driver if information of the road hazard or traffic condition is assessed to be relevant
to the driver. The driver is then able to take appropriate actions to react to the situation accordingly.
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7 ETSI TS 103 831 V2.2.1 (2024-04)
The Release 1 edition of the DEN service has been published as ETSI EN 302 637-3 [i.9] called the DEN basic service.
The first Release 2 version of the present document provides an improved specification of the Release 1 version as a
basis for future Release 2 versions of the DEN service. The present document specifies extensions to the DENM
Release 1 format to support additional use cases in a way allowing the facilities layer standard to be used with different
security and lower layer technologies.
All future Release 2 versions will be based on the latest Release 1 version of the DEN service and will be backwards
compatible with it in the sense that Release 1 implementations can receive and decode Release 2 DENM and utilize the
Release 1 content without the need to understand the Release 2 content.
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8 ETSI TS 103 831 V2.2.1 (2024-04)
1 Scope
The present document provides the specification of the Release 2 DEN service.
More specifically, the present document specifies the syntax and semantics of the "Decentralized Environmental
Notification Message" (DENM) and the DENM protocol handling.
The DEN service may be implemented in a vehicle ITS-S, a road side ITS-S, a personal ITS-S or a central
ITS-S.
2 References
2.1 Normative 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
https://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.
The following referenced documents are necessary for the application of the present document.
[1] ETSI TS 103 836-4-1: "Intelligent Transport Systems (ITS); Vehicular Communications;
GeoNetworking; Part 4: Geographical addressing and forwarding for point-to-point and point-to-
multipoint communications; Sub-part 1: Media-Independent Functionality; Release 2".
[2] ETSI TS 103 836-5-1: "Intelligent Transport Systems (ITS); Vehicular Communications;
GeoNetworking; Part 5: Transport Protocols; Sub-part 1: Basic Transport Protocol; Release 2".
[3] ETSI TS 102 965: "Intelligent Transport Systems (ITS); Application Object Identifier (ITS-AID);
Registration; Release 2".
[4] ETSI TS 103 899: "Intelligent Transport Systems (ITS); Vehicular Communications; Geographical
Area Definition; Release 2".
[5] ETSI TS 102 894-2: "Intelligent Transport Systems (ITS); Users and applications requirements;
Part 2: Applications and facilities layer common data dictionary; Release 2".
[6] Recommendation ITU-T X.691/ISO/IEC 8825-2: "Information technology - ASN.1 encoding
rules: Specification of Packed Encoding Rules (PER)".
[7] ETSI EN 302 890-2: Intelligent Transport Systems (ITS); Facilities Layer function; Part 2:
Position and Time management (PoTi); Release 2"Intelligent Transport Systems (ITS); Facilities
Layer function; Part 2: Position and Time management (PoTi); Release 2".
[8] ETSI TS 103 097: "Intelligent Transport Systems (ITS); Security; Security header and certificate
formats; Release 2".
[9] ETSI TS 102 940: "Intelligent Transport Systems (ITS); Security; ITS communications security
architecture and security management; Release 2".
[10] ETSI TS 103 141: "Intelligent Transport Systems (ITS); Facilities layer function; Multi-Channel
Operation (MCO) for Cooperative ITS (C-ITS); Release 2".
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9 ETSI TS 103 831 V2.2.1 (2024-04)
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 TR 102 638 (V2.1.1): "Intelligent Transport Systems (ITS); Vehicular Communications;
Basic Set of Applications; Release 2".
[i.2] Car2Car Communication Consortium: "Basic System Profile".
[i.3] Car2Car Communication Consortium: "Guidance for day 2 and beyond roadmap".
[i.4] C-Roads: "Harmonised C-ITS Specifications for Europe".
[i.5] ETSI TS 103 938: "Intelligent Transport Systems (ITS); Vehicular Communications; Basic Set of
Applications; Local Dynamic Map (LDM); Release 2".
[i.6] ETSI TS 103 898: "Intelligent Transport Systems (ITS); Communications Architecture;
Release 2".
[i.7] ETSI TS 103 836-3: "Intelligent Transport Systems (ITS); Vehicular Communications;
GeoNetworking; Part 3: Network Architecture; Release 2".
[i.8] ISO EN 17419: "Intelligent Transport Systems - Cooperative Systems - Classification and
management of ITS applications in a global context".
[i.9] ETSI EN 302 637-3 (V1.3.1): "Intelligent Transport Systems (ITS); Vehicular Communications;
Basic Set of Applications; Part 3: Specifications of Decentralized Environmental Notification
Basic Service".
[i.10] ETSI TS 103 301: "Intelligent Transport Systems (ITS); Vehicular Communications; Basic Set of
Applications; Facilities layer protocols and communication requirements for infrastructure
services; Release 2".
[i.11] ETSI TR 103 832: "Intelligent Transport Systems (ITS); Vehicular Communications; Basic Set of
Applications; Study on ITS Support for Pre-Crash based Applications; Release 2".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the terms given in ETSI TS 103 301 [i.10], ETSI TS 103 898 [i.6], ETSI
TS 102 894-2 [5], ETSI TS 103 938 [i.5] and the following apply:
actionId: identifier of a detected event
À La Carte container: container of DENM that includes information of the detected event in addition to management
container, situation container and location container
NOTE: Due to coding constraints in programming language, the term "alacarte" is also used.
awareness area: geographic area in which information concerning the event is potentially applicable for use or for
further distribution
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10 ETSI TS 103 831 V2.2.1 (2024-04)
basic set of applications: group of applications, supported by the vehicular communication system
NOTE: The BSA is defined in ETSI TR 102 638 [i.1].
cancellation Decentralized Environmental Notification Message (DENM): DEN message type generated by the
ITS-S, which originated the new DENM, indicating the event termination
Decentralized Environmental Notification (DEN) basic service: facility at the facilities layer to support ITS-S
applications, DENM management and DENM dissemination
Decentralized Environmental Notification Message (DENM): ITS facilities layer PDU providing event information
Decentralized Environmental Notification Message (DENM) protocol: ITS facilities layer protocol that operates the
DENM transmission, forwarding and reception
destination area: geographical area for DENM dissemination
NOTE: The destination area is specified in ETSI TS 103 899 [4].
downstream traffic: portion of traffic in a given direction that is beyond (past) a certain point and is going away from
it
event: road hazard, driving environment, or traffic condition
facility: functionality, service or data provided by the ITS facilities layer
forwarding Intelligent Transport System Station (ITS-S): ITS-S that forwards DENMs and implements the DENM
protocol
location container: container of DENM that includes location data of the detected event
management container: container of DENM that includes management data for DENM protocol
negation Decentralized Environmental Notification Message (DENM): DEN message type generated by an ITS-S
other than the ITS-S, which originated the new DENM, indicating the event termination
new Decentralized Environmental Notification Message (DENM): DEN message type indicating that the event is
detected for the first time
originating Intelligent Transport System Station (ITS-S): ITS-S that generates DENMs and implements the DENM
protocol
receiving Intelligent Transport System Station (ITS-S): ITS-S that receives DENMs from the ITS networking &
transport layer and implements the DENM protocol
situation container: container of DENM that includes data related to the detected event
update Decentralized Environmental Notification Message (DENM): DEN message type indicating the evolution of
the event
upstream traffic: portion of traffic in a given direction that has not yet arrived at a certain point and is going towards it
3.2 Symbols
For the purposes of the present document, the following symbols apply:
actionId Identifier of an event that is detected by an ITS-S
appDENM_trigger Application request type to generate a new DENM for a newly detected event
appDENM_update Application request type to generate an update DENM for an update of the event
appDENM_termination Application request type to generate a cancellation or negation DENM for termination of
the event
detectionTime Timestamp at which an event or event update/termination is detected
IF.DEN1 Interface between the DEN service and ITS-S applications for DENM transmission
IF.DEN2 Interface between the DEN service and ITS-S applications for DENM reception
IF.Mng Interface between the DEN service and the ITS management entity
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11 ETSI TS 103 831 V2.2.1 (2024-04)
IF.MCO Interface between the DEN service and the MCO facility layer entity
IF.N&T Interface between the DEN service and the ITS networking & transport layer
IF.SEC Interface between the DEN service and the ITS security entity
referenceTime Timestamp at which a new, update or cancellation DENM is generated by the DEN
service
NOTE: A negation DENM contains the referenceTime of the DENM that is negated.
repetitionDuration Duration of the DENM repetition
repetitionInterval Time interval of the DENM repetition
stationId Identifier of an ITS-S
T_F_Validity Timer that indicates the end of the DENM processing of one specific actionId of the
forwarding ITS-S
T_Forwarding Timer for the scheduling of the DENM forwarding by the forwarding ITS-S
T_O_Validity Timer that indicates the end of the DENM processing of one specific actionId of the
originating ITS-S
T_R_Validity Timer that indicates the end of the DENM processing of one specific actionId of the
receiving ITS-S
T_Repetition Timer for the scheduling of the DENM repetition by the originating ITS-S
T_RepetitionDuration Timer that indicates the end of the DENM repetition
termination Parameter that indicates the termination of an event
transmissionInterval Time interval for DENM transmission
validityDuration Duration of the DENM validity
3.3 Abbreviations
For the purposes of the present document, the abbreviations given in ETSI TS 103 898 [i.6] and the following apply:
ASN.1 Abstract Syntax Notation One
BSA Basic Set of Applications
BTP Basic Transport Protocol
C2C-CC Car to Car Communication Consortium
DE Data Element
DEN Decentralized Environmental Notification
DENM Decentralized Environmental Notification Message
DF Data Frame
EEBL Electronic Emergency Break Light
GN GeoNetworking
HMI Human Machine Interface
ISO International Standardization Organization
ITS Intelligent Transport System
ITS-AID ITS-Application IDentifier
ITS-S ITS Station
IVIM In-Vehicle Information Message
KAF Keep Alive Forwarding
LDM Local Dynamic Map
MAPEM MAP Extended Message
MSB Most Significant Bit
MCI MCO Control Information
MCO Multi Channel Operations
OSI Open System Interconnection
PCI Protocol Control Information
PDU Protocol Data Unit
PER Packed Encoding Rules
SSP Service Specific Permissions
TS Technical Specification
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12 ETSI TS 103 831 V2.2.1 (2024-04)
4 DEN service introduction
4.1 Background
The Decentralized Environmental Notification service (DEN) is an application support functionality operating at the
facilities layer. The DEN service is responsible for the generation of DEN Messages (DENMs) based on received
triggering information from applications. It is also responsible for the processing of received DENMs from other C-ITS
stations. The DEN service is especially suited for the exchange of event based safety related information. The DENM
information is mainly used by ITS applications in order to alert road users of a detected event using ITS communication
technologies. DENM is used to describe a variety of events that can be detected by ITS Stations (ITS-S). A set of ITS
applications, ITS services and use cases are specified in the ETSI Basic Set of Applications [i.1], in the C2C-CC Basic
System Profile [i.2] and the C-Roads Release [i.4]. Further use cases are specified in the C2C-CC Roadmap [i.3].
The dissemination of DENM by an ITS-S is operated by DENM protocol.
The general processing procedure of an ITS use case that is supported by the DENM protocol is as follows:
• Upon detection of an event, an ITS-S transmits DENMs in order to disseminate the information about this
event to other ITS-Ss located inside a destination area. The ITS-S that generates the DENM is denoted as
originating ITS-S.
• DENM transmission is initiated and terminated by an ITS-S application at the ITS application layer.
• The transmission of a DENM may be repeated.
• DENM transmission may persist as long as the event is present.
• An ITS-S may forward a DENM. This ITS-S is denoted as forwarding ITS-S.
• The termination of DENM transmission is either automatically achieved by the facilities layer, i.e. the DEN
service of the originating ITS-S when a predefined expiry time is reached, or by an ITS-S application that
requests the generation of a DENM to inform that the event has terminated.
• An ITS-S, which receives a DENM, processes the information and may decide to present an appropriate
warning or information to user, as long as the information in the received DENM is relevant to the ITS-S. This
ITS-S is denoted as receiving ITS-S.
A general inter-layer and inter-ITS-Ss dataflow for DENM exchange is provided in Figure 1.
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13 ETSI TS 103 831 V2.2.1 (2024-04)
Originating ITS-S Forwarding ITS-S Receiving ITS-S
Sensors and/or in
In-vehicle system
vehicle system
Sensor information Information/warning
ITS application layer
ITS-S application ITS-S application
Application request, event information Event information
ITS facilities layer
service service service
DEN basic service DEN basic service DEN basic service
Transmission request, DENM DENM DENM
ITS
ITS ITS ITS
networking&transport
networking&transport networking&transport networking&transport
layer
ITS access layer
ITS access ITS access ITS access
technologies technologies technologies
ITS link ITS link
Figure 1: General data flow for ITS-S application supported by the DEN service
The solid lines illustrate the dataflow that is mandatory for all ITS applications using the DENM protocol. The dotted
lines illustrate the dataflow that may apply only in certain situations.
NOTE: A DENM may be forwarded by intermediate ITS-Ss in order to disseminate DENM from the originating
ITS-S to the receiving ITS-S, if the receiving ITS-S is not located in the direct communication range of
the originating ITS-S. This forwarding is realized by the ITS networking & transport layer. In addition,
the DEN service may provide forwarding functionality at the facilities layer, in order to maintain the
DENM retransmission in certain situations, for example when the originating ITS-S has lost the capability
to repeat DENM transmission. This optional facilities layer forwarding functionality is illustrated as
dotted lines in Figure 1.
4.2 Services provided by the DEN service
The DEN service provides services to entities at the ITS application layer. At the originating ITS-S, an ITS-S
application may trigger, update and terminate the transmission of DENMs. At the receiving ITS-S, the DEN service
processes received DENMs and makes the information available for usage by ITS-S applications. Optionally, the DEN
service may also provide forwarding functionality.
The DEN service uses the services provided by the protocol entities of the ITS networking & transport layer to
disseminate DENM.
NOTE 1: Typically, for road safety ITS applications, the destination of a DENM transmission are ITS-Ss that are
located in a pre-defined geographic area in which the event information may be relevant for traffic
participants, e.g. close to the detected event reference position.
NOTE 2: A DENM may also be disseminated over a long distance or to a central ITS-S, such as for vehicle
rerouting or road traffic management purposes.
A DENM contains information related to an event that has potential impact on road safety or traffic condition. An event
is characterized by an event type, an event reference position, a detection time and a duration. These attributes may
change over space and over time.
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14 ETSI TS 103 831 V2.2.1 (2024-04)
In some situations, the originating ITS-S transmits a DENM of an event originated by the vehicle itself, such as an
electronic brake light event. The originating ITS-S manages the tran
...