ETSI TS 102 687 V1.2.1 (2018-04)

Intelligent Transport Systems (ITS); Decentralized Congestion Control Mechanisms for Intelligent Transport Systems operating in the 5 GHz range; Access layer part

RTS/ITS-00430

General Information

• Status: Published
• Publication Date: 26-Apr-2018
• Technical Committee: ITS WG4 - Media and Medium related
• Current Stage: 12 - Completion
• Due Date: 15-May-2018
• Completion Date: 27-Apr-2018
• Mandate: M/453

Standards Content (Sample)

ETSI TS 102 687 V1.2.1 (2018-04)






TECHNICAL SPECIFICATION
Intelligent Transport Systems (ITS);
Decentralized Congestion Control Mechanisms for
Intelligent Transport Systems operating in the 5 GHz range;
Access layer part

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2 ETSI TS 102 687 V1.2.1 (2018-04)



Reference
RTS/ITS-00430
Keywords
ITS, radio, transmission
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3 ETSI TS 102 687 V1.2.1 (2018-04)
Contents
Intellectual Property Rights . 4
Foreword . 4
Modal verbs terminology . 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 Overview . 7
4.1 Introduction . 7
4.2 Architecture . 7
4.3 DCC_ACC component . 7
5 Algorithms . 8
5.1 Introduction . 8
5.2 Requirements . 8
5.3 Reactive approach . 8
5.4 Adaptive approach . 9
Annex A (informative): Parameter setting of reactive approach . 10
Annex B (informative): Packet handling to meet channel occupancy limit δ . 11
Annex C (informative): Bibliography . 12
Annex D (informative): Change History . 13
History . 14


ETSI

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4 ETSI TS 102 687 V1.2.1 (2018-04)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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 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
Decentralized congestion control (DCC) is a necessity in ad hoc networks where the number of communicating stations
varies and is not known in advance. Vehicular ad hoc network (VANET) presents a challenge because in a few seconds
a very high density of vehicles can be in radio range of each other due to for example an accident. A DCC algorithm
needs to cope with few as well as many communicating stations within radio range. The medium access control (MAC)
algorithm schedules transmissions to avoid interference between communicating stations. The wireless channel is a
finite resource and when the number of required resources exceeds available resources, the DCC algorithm needs to
shape the data traffic injected by each communicating station to avoid channel congestion. All MAC schemes applied in
an ad hoc setting such as the high-speed vehicular environment need to have DCC. However, DCC cannot solely
operate on the MAC layer since the MAC layer is not aware of the applications running in the station. DCC is a
cross-layer functionality and applications need to be aware of the current channel activity to prioritize between different
internal data traffic sources once DCC will restrict transmissions.
In infrastructure based networks (i.e. networks containing a centralized network controller such as an access point or
base station) when the required resources exceed available resources, the centralized network controller can for example
decide to not grant access to the network or run certain links with reduced quality of service. But for a VANET,
communicating stations are responsible for a graceful degradation of applications, where some might be temporarily
shut down while others can continue without disruption when the DCC is active.
DCC is also a way to divide the resources among the communicating stations and to restrict that some stations operate
using all resources. ETSI EN 302 571 [1] put up upper limits on the DCC by using duty cycle requirements.
ETSI

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5 ETSI TS 102 687 V1.2.1 (2018-04)
1 Scope
The present document describes the means of controlling the data traffic injected to a frequency channel from the access
layer perspective. The outlined algorithms are only applicable to ITS-G5 [i.4].
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 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".
[2] ETSI TS 103 175 (V1.1.1): "Intelligent Transport Systems (ITS); Cross layer DCC management
entity for operation in the ITS G5A and ITS G5B medium".
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 TS 102 636-4-2 (V1.1.1): "Intelligent Transport Systems (ITS); Vehicular Communications;
GeoNetworking; Part 4: Geographical addressing and forwarding for point-to-point and point-to-
multipoint communications; Sub-part 2: Media-dependent functionalities for ITS-G5".
[i.2] ETSI TR 101 612: "Intelligent Transport Systems (ITS); Cross Layer DCC Management Entity for
operation in the ITS G5A and ITS G5B medium; Report on Cross layer DCC algorithms and
performance evaluation".
[i.3] G. Bansal, J. B. Kenney, and C. E. Rohrs: "LIMERIC: A Linear Message Rate Control Algorithm
for DSRC Congestion Control," in IEEE Transactions on Vehicular Technology, vol. 62, no. 9,
pp. 4182-4197, July 2013.
[i.4] ETSI EN 302 663 (V1.2.1): "Intelligent Transport Systems (ITS); Access layer specification for
Intelligent Transport Systems operating in the 5 GHz frequency band".
ETSI

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6 ETSI TS 102 687 V1.2.1 (2018-04)
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
channel busy ratio (CBR): time-dependent value between zero and one representing the fraction of time that a single
radio channel is busy with transmissions
duty cycle: defined as the ratio, expressed as a percentage of the transmitter total "on" time on one carrier frequency,
relative to 1 second period
3.2 Symbols
For the purposes of the pres
...