One document matched: draft-petrescu-its-cacc-sdo-05.xml


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     docName="draft-petrescu-its-cacc-sdo-05.txt"
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  <front>

    <title abbrev="C-ACC at SDOs and IP Gap Analysis">
      Cooperative Adaptive Cruise Control and Platooning at SDOs and
      Gap Analysis
    </title>

    <author initials='A.' surname="Petrescu" fullname='Alexandre Petrescu'
	    role="editor">
      <organization>CEA, LIST</organization>
      <address>
	<postal>
	  <street>
	    CEA Saclay
	  </street>
	  <city>
	    Gif-sur-Yvette
	  </city>
	  <region>
	    Ile-de-France
	  </region>
	  <code>
	    91190
	  </code>
	  <country>
	    France
	  </country>
	</postal>
	<phone>
	  +33169089223
	</phone>
	<email>
	  Alexandre.Petrescu@cea.fr
	</email>
      </address>
    </author>

    <author initials='J.' surname="Huang" fullname='James Huang'>
      <organization>Huawei Technologies</organization>
      <address>
    	<postal>
    	  <street></street>
    	  <city>Shenzhen</city>
    	  <region></region>
    	  <code></code>
    	  <country>China</country>
    	</postal>
    	<phone></phone>
    	<email>james.huang@huawei.com</email>
      </address>
    </author>

    <author initials='T.' surname="Ernst" fullname='Thierry Ernst'>
      <organization>
	Mines ParisTech
      </organization>
      <address>
	<postal>
	  <street>
	  </street>
	  <city>
	    Paris
	  </city>
	  <region>
	  </region>
	  <code>
	    75006
	  </code>
	  <country>
	    France
	  </country>
	</postal>
	<phone>
	</phone>
	<email>
	  Thierry.Ernst@mines-paristech.fr
	</email>
      </address>
    </author>

    <author initials='R.' surname="Buddenberg" fullname="Rex Buddenberg">
      <organization>
	Retired
      </organization>
      <address>
	<postal>
	  <street>
	  </street>
	  <city>
	  </city>
	  <region>
	  </region>
	  <code>
	  </code>
	  <country>
	    US
	  </country>
	</postal>
	<phone>
	</phone>
	<email>
	  buddenbergr@gmail.com
	</email>
      </address>
    </author>    
    <author fullname="Charles E. Perkins" initials="C.E." surname="Perkins">
      <organization abbrev="Futurewei">Futurewei Inc. </organization>
      <address>
        <postal>
          <street>2330 Central Expressway</street>

          <city>Santa Clara</city>

          <code>95050</code>

          <region>CA</region>

          <country>USA</country>
        </postal>

        <phone>+1-408-330-4586</phone>

        <email>charliep@computer.org</email>
      </address>
    </author>

    <date/>

    <!-- Meta-data Declarations -->

    <area>Internet</area>

    <workgroup>Network Working Group</workgroup>

    <!-- WG name at the upperleft corner of the doc, IETF is fine for
         individual submissions.  If this element is not present, the
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    <keyword>
      C-ACC, Platooning, V2V, Vehicle-to-Vehicle communications, LTE
      D2D, device-to-device communications
    </keyword>

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    <abstract>
      <t>
	This document describes the use-cases of Cooperative Adaptive
	Cruise Control, and Platooning, as defined by several
	Standards Development Organizations such as ETSI, IEEE P1609,
	SAE, 3GPP, ISO and FirstNet.
      </t>
      <t>
	C-ACC and Platooning involve concepts of direct
	vehicle-to-vehicle, and device-to-device communications, which
	are developed by 3GPP following on work done within the METIS EU
	project.  They are illustrated very clearly in emergency
	settings such as FirstNet.
      </t>
      <t>
	IP packets - instead of link-layer frames - are pertinent
	for C-ACC and Platooning use-cases because applications for
	road safety such as WAZE, iRezQ and Coyote (currently involving
	infrastructure) make use of IP messages, and have proved successful
	in deployments.  Applications such as Sentinel operate directly
	between vehicles, but currently use messages not carried over IP.
      </t>

    </abstract>
  </front>

  <middle>
    <section title="Introduction">
	<t>
	  Cooperative Adaptive Cruise Control (C-ACC) and Platooning
	  are two use-cases described recently by other Standards
	  Development Organizations (SDOs).  C-ACC <xref
	  target='CACC-def'/> is understood as a automated formation
	  of chains of automobiles following each other at constant
	  speed.  This offers more comfort for human drivers on long
	  journeys on straight roads.
	</t>
	<t>
	  Simple 'cruise control' was the automation of speed
	  maintenance at a single automobile (increase torque if
	  uphill, smoothly brake downhill, such as to maintain
	  constant speed).  The term "Adaptive Cruise Control" was
	  used earlier in the literature <xref target='ACC-def'/>.
	  The concept of C-ACC aims at the same level of automation
	  but in a cooperative manner between several vehicles: while
	  in CC mode, when a vehicle in front slowly decelerates, this
	  vehicle will also do, such as to maintain distance, and
	  relieve driver from taking control over.
	</t>
	<t>
	  Platooning is another concept related to larger vehicles following
	  each other.  The goal in this case is more than just comfort
	  - large gains are expected in terms of gas consumption: when
	  large vehicles can follow each other at small distance the
	  air-drag is much lower, reducing gas consumption, tyre use,
	  and more.
	</t>

	<t>
	  Both C-ACC and Platooning must rely on wireless communications
	  between vehicles (in addition to more immediate indicators like
	  signal echoes - radars and cameras).  These exchanges may
	  happen in a direct manner (direct vehicle to vehicle
	  communications) or with assistance from a fixed
	  communication infrastructure
	  (vehicle-to-infrastructure-to-vehicle communications).
	</t>

	<t>
	  This document presents the V2V-based C-ACC and Platooning
	  use-cases as described at ETSI <xref target='ETSI-CACC'/>,
	  SAE <xref target="SAE-V2V"/>, ISO <xref target="ISO-CACC"/>,
	  3GPP <xref target="GPP-TR-22-885"/>, ITU <xref
	  target="ITU-V2V"/>, ITS Info-communications Forum of Japan
	  <xref target="its-infocomm-CACC"/> and more.  These
	  use-cases are widely accepted as examples of
	  Vehicle-to-Vehicle applications.
	</t>

	<t>
	  In emergency settings the concepts of direct
	  vehicle-to-vehicle communications are of paramount
	  importance.  FirstNet, as described
<!--  CEP: Citation needed. -->
	  later in this document, covers V2V, V2I and V2I2V
	  communication needs, together with strong security
	  requirements.
	</t>

	<t>
	  In the market, several systems for vehicular communications
	  have demonstrated a number of benefits in the context of
	  vehicle-to-vehicle communications.
<!--  CEP: Citations needed. -->
	  <list style='symbols'>
          <t>
	    The Sentinel system is used between vehicles to warn each other
	    about approach;
	  </t>
	  <t>
	    WAZE on smartphones created a community where
	    users influence others about the route choice;
	  </t>
	  <t>
	    iRezQ and Coyote communicate between vehicles, via
	    infrastructure, about route risks.
	  </t>
	  </list>
	</t>
	
	<!-- <t>  -->
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	<!-- </t> -->
	<t>
	  In <xref target="I-D.petrescu-ipv6-over-80211p"/> the use of
	  IPv6 over 802.11p is described.  This link layer is
	  potentially to be used in direct vehicle-to-vehicle
	  communications, among several other possibilities.
	</t>
	
    </section>
	
    <section title="Terminology">
      <t>
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
        "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
        document are to be interpreted as described in
	<xref target="RFC2119">RFC 2119</xref>.
      </t>
      <t>
	3GPP: Third Generation Partnership Project.
      </t>
      <t>
	3G: Third Generation.
      </t>
      <t>
	4G: Fourth Generation.
      </t>
      <t>
	5G: Fifth Generation of mobile networks.
      </t>
      <t>
	apps: applications.
      </t>
      <t>
	AODV: Ad-hoc On-demand Distance Vector.
      </t>
      <t>
	ARIB: Association of Radio Industries and Businesses.
      </t>
      <t>
	BSS: Basic Service Set.
      </t>
      <t>
	C-ACC: Cooperative Adaptive Cruise Control.
      </t>
      <t>
	CAM: Cooperative Awareness Message.
      </t>
      <t>
	CC: Cruise Control.
      </t>
      <t>
	CEN: European Committee for Standardizatin (Comité européen de
	normalisation, fr.)
      </t>
      <t>
	DeNM: Decentralized Environmental Notification Message.
      </t>
      <t>
	DMM: Distributed Mobility Management.
      </t>
      <t>
	DSRC: Dedicated Short Range Communications, as referenced in
	the United States FCC Report
	and Order for the frequency allocation for 5.9GHz band in
	North America, which refers to "DSRC" as the ASTM (earlier
	"American Society for Testing and Materials") standard
	"E2213".  Other interpretations of "DSRC" include the DSRC
	standard developed in ISO TC204 WG17 and CEN TC278 which uses
	a different frequency spectrum than the one used in North
	America.
      </t>
      <t>
	E2E: end-to-end.
      </t>
      <t>
	EMS: Emergency and Medical System providers.
      </t>
      <t>
	EPC: Evolved Packet Core.
      </t>
      <t>
	ETSI: European Telecommunications Standards Institute.
      </t>
      <t>
	E-UTRAN: Evolved Universal Terrestrial Radio Access Network.
      </t>
      <t>
	EU: European Union.
      </t>
      <t>
	FAST: fast.
      </t>
      <t>
	FCC: Federal Communications Commision.
      </t>
      <t>
	FNTP: Fast Networking and Transport layer Protocol.
      </t>
      <t>
	FSAP: Fast Service Advertisement Protocol.
      </t>
      <t>
	I2V: Infrastructure to Vehicle.
      </t>
      <t>
	ICT: Information and Communication Technologies.
      </t>
      <t>
	IEEE: Institute of Electrical and Electronics Engineers.
      </t>
      <t>
	IoT: Internet of Things.
      </t>
      <t>
	IP: Internet Protocol.
      </t>
      <t>
	IPv6: Internet Protocol version 6.
      </t>
      <t>
	IPTV: Internet Protocol Television
      </t>
      <t>
	ISO: International Organization for Standardization.
      </t>
      <t>
	ITS: Intelligent Transportation Systems.
      </t>
      <t>
	ITS-G5: ITS Gigahertz Five.
      </t>
      <t>
	ITU: International Telecommunication Union.
      </t>
      <t>
	ITU-T: Telecommunication Standardization Sector of the
	International Telecommunication Union.
      </t>
      <t>
	IVC-RVC:
      </t>
      <t>
	LiFi: Light Fidelity.
      </t>
      <t>
	LTE
	: Long-Term Evolution.
      </t>
      <t>
	METIS: Mobile and wireless communications Enablers for
	Twenty-twenty (2020) Information Society.
      </t>
      <t>
	OBU: On-Board Unit.
      </t>
      <t>
	OCB: Outside the Context of a BSS identifier.
      </t>
      <t>
	PHY: physical layer.
      </t>
      <t>
	ProSe: Proximity Service.
      </t>
      <t>
	PSAP: Public Safety Answering Points.
      </t>
      <t>
	RA: Router Advertisement.
      </t>
      <t>
	SAE: Society of Automotive Engineers.
      </t>
      <t>
	SDO: Standards Development Organization.
      </t>
      <t>
	SG: Study Group.
      </t>
      <t>
	TC: Technical Committee.
      </t>
      <t>
	TR: Technical Report.
      </t>
      <t>
	UE: User Equipment.
      </t>
      <t>
	US: United States.
      </t>
      <t>
	V2V: Vehicle-to-Vehicle communications.
      </t>
      <t>
	V2X: Vehicle-to-'other' communications.
	E.g. Vehicle-to-Infrastructure (V2I), Vehicle-to-Pedestrian
	(V2P), Vehicle-to-Nomadic[device] (V2N), Vehicle-to-Device
	(V2D) and more.
      </t>
      <t>
	V2I2V: Vehicle to Infrastructure to Vehicle.
      </t>
      <t>
	WAVE: Wireless Access for Vehicular Environments.
      </t>
      <t>
	WG1: Work Group 1.
      </t>
      <t>
	WiFi: Wireless Fidelity.
      </t>
      <t>
	WLAN: Wireless Local Area Network.
      </t>

    </section>

    <section anchor="etsi"
	     title="ETSI ITS C-ACC and Platooning use-case and reqs">
      <t>
	ETSI Technical Committee Intelligent Transportation Systems
	(ETSI TC ITS) is responsible for the development and
	maintenance of standards, specifications and other reports on
	the implementation of V2V communications in Cooperative
	ITS. Its scope extends from the wireless access (excluding
	issues in radio frequency) to generic services and
	corresponding applications.  Security and tests specifications
	are also covered.  This responsibility is reflected in the
	organization with five working groups that make up the
	committee. Among them, WG1 is responsible of the facilities
	and applications needs.
      </t>
      <t>
	Under the EU Mandate M/453, TC ITS has developed a minimum set
	of standards (Release 1) for systems interoperability during
	initial deployment.  The list of standards and specifications
	are provided in the publicly available report ETSI TR 101
	607. A second release of the standards is being prepared. It
	should support more complex use cases, possible integration
	with other technologies as well as a more elaborate
	consideration of access networks other than the ITS-G5
	(European profile of IEEE 802.11p).  The TC ITS WG1 is
	currently working on two separate work items for
	pre-standardization studies on C-ACC (DTR/ITS-00164) and
	Platooning (DTR/ITS-00156).  The scope of the target technical
	reports is to describe the relevant use cases that could be
	enabled by Cooperative ITS, to survey the existing related
	standards and to identify what new features and standards are
	needed to support these use cases.
      </t>
      <t>
	The C-ACC definition in TR 103 299 will soon be made public.
      </t>
    </section>

    <section anchor="IEEE"
	    title="The C-ACC Use of Protocols specified by IEEE 1609 Standards">
      <t>
	The C-ACC interacts with the presentation layer services which
	in turn use the communication protocols specified in IEEE
	1609 standards.
      </t>
      <t>
	One perspective from IEEE P1609 is that Cooperative Adaptive
	Cruise Control (CACC) represents an "application".  An
	application is typically software whose communication needs
	are situated at the upper layers of a communication stack -
	e.g. the Application Layer.  As such it is little relevant to
	IEEE P1609; P1609 is concerned more with physical, data-link
	and network communication layers.  On another hand, a
	perspective well considered in IEEE P1609 is that C-ACC and
	Platooning may be more relevant to the Society of Automotive
	Engineers.
      </t>
    </section>

    <section anchor="SAE" title="SAE perspective on C-ACC and Platooning">
      <t>
	The Society of Automotive Engineers (SAE) concerns itself with
	data exchanges and host system requirements for applications.
	The SAE DSRC Technical Committee (DSRC: Dedicated Short-Range
	Communications) is working on C-ACC within the Cooperative
	Vehicle Task Force.  In addition, the SAE On-Road Vehicle
	Automation Committee is working on a use-case relevant to
	C-ACC towards realization of a reference
	architecture.
      </t>
      <t>
	In addition to C-ACC, SAE is completing performance
	requirements for V2V Safety Communications to profile a
	probable US-mandated implementation.  The concept is that a
	vehicle would send a link-layer message set (Basic Safety
	Message, plus path history and path prediction extensions) to
	a host vehicle to enable the host vehicle to use the
	transmitted information in a driver warning or alert
	algorithm.  Because it is used for safety, it is of paramount
	importance that the messages are authenticated through a
	Security Credential Management System.
      </t>
      <t>
	The SAE DSRC TC activities are in cooperative agreement to
	ETSI ITS WG1, as there are information exchanges between the
	two bodies <xref target="SAE-V2V"/>.
      </t>

    </section>

    <section title="3GPP and EU projects using LTE Device-to-Device concepts" 
	     anchor="pp"	       
	     >

      <section title="3GPP">
        <t>
	  The Proximity Service (ProSe) allows a UE to discover and
	  communicate with other UEs that are in proximity directly or
	  with the network assistance. This may also be called as
	  Device-to-Device (D2D) communication. ProSe is intended for
	  purposes such as public security, network offloading, etc
	  <xref target="GPP-TR-22-803"/>.
	</t>

        <t>
	  The ProSe Communication path could use E-UTRAN or WLAN.
	  In the case of WLAN, only ProSe-assisted WLAN direct
	  communication (i.e. when ProSe assists with connection
	  establishment management and service continuity) is
	  considered <xref target="GPP-TS-22-278"/>.
	</t>

        <t>
	  The work on ProSe is initiated in 3GPP Release 12. Some
	  enhancements are being added in Release 13,
<!--  CEP: Explanation needed. -->
	  e.g. Restricted ProSe Discovery. Some use cases are
	  identified in <xref target="GPP-TR-22-803"/>, but most of
	  which are intended for common mobile users, e.g. pedestrians,
	  but not for vehicles moving at high speed.
	  The latency in ProSe communication may be a problem for
	  V2X.
	</t>

        <t>
	  ProSe does not support V2X communication until at least
	  Release 14, but it has some very good characteristics
	  which makes it a good candidate for V2X besides
	  DSRC. ProSe communication does not have to go through the
	  EPC, which will significantly reduce the latency. ProSe
	  also supports group and broadcast communication by means of
	  a common communication path established between the UEs.
	</t>

        <t>
	  There are some efforts within 3GPP Release 14, trying to
	  address V2X communication. The efforts are proposed by
	  experts in the industry, and may be subject to change.
	  These efforts include the following, not an exhaustive list:

	  <list style='symbols'>
            <t>
	      To address the V2X use cases in 3GPP. Some use cases
	      have been defined by other SDOs, e.g. ETSI ITS; 3GPP can
	      reference to them.  Requirements for V2X communication
	      should also be considered, for example network delay,
	      packet loss rate, etc. <xref target="METIS-D1.1"/>
	      already propose some requirements, but those are
	      intended for future mobile network, which may be too
	      critical for LTE.
	    </t>

            <t>
	      To address V2X applications and messages. The messages
	      may include message defined in SAE J2735, ETSI
	      Cooperative Awareness Message (CAM) and ETSI
	      Decentralized Environmental Notification Message (DeNM).
	      The messages defined by different SDOs might be similar
	      to each other.
	    </t>

            <t>
	      Study of possibility to add enhancements to ProSe, and
	      to make it able to support and enhance DSRC.
	    </t>

            <t>
	      Study of using existing LTE technologies for
	      unicast/multicast/broadcast communication.
	    </t>
	  </list>
	</t>

	<t>
	  <xref target="GPP-TR-22-885"/> studies many V2X services
	  using LTE.  These services include V2V communication
	  (e.g. Cooperative Adaptive Cruise Control, Forwarding
	  Collision Warning, etc), V2I/V2N communication (e.g. Road
	  Safety Services) and vehicle to pedestrian
	  communication. The services' pre-condition, service flow,
	  post-condition, including some network communication
	  requirements, such as delay, messages frequency and message
	  size, are ayalyzed.
	</t>

	<t>
	  In <xref target="GPP-TR-22-885"/>, Cooperative Adaptive
	  Cruise Control (CACC) allows a vehicle to join a group of
	  CACC vehicles; the benefits are to improve road
	  congestion and fuel efficiency. Member vehicles of CACC
	  group should periodically broadcast messages including the
	  CACC group information, such as speed and gap policies, etc.
	  If a vehicle outside the group wants to join, it should send
	  a request to the group.  If a member of the CACC group
	  accepts the request, it should send a confirm message and
	  provide necessary distance gap; and members of the group
	  will update their group information. When a member wants to
	  leave the CACC group, it broadcasts a goodbye message,
	  and the driver once again assumes control of the vehicle.
	</t>
	
      </section>

      <section title="METIS">
        <t>
	  METIS is co-funded by the European Commission as an
	  Integrated Project under the Seventh Framework Programme for
	  research and development (FP7).
	</t>

        <t>
	  METIS defines test cases and requirements of "Traffic
	  safety and efficiency", as depicted in <xref
	  target="METIS-D1.1"/>, which is intended for 5G in 2020
	  but may also be applicable for LTE and subsequent systems.
	</t>

        <t>
	  The use cases include:
	  <list style='numbers'>
	    <t>
	      Dangerous situation that can be avoided by means of V2V
	      communications.
	    </t>	   
            <t>
	      Dangerous situation with vulnerable road users
	      (i.e. pedestrians, cyclists,...) that can be avoided by
	      means of V2D communications. "D" can denote any cellular
	      device that the vulnerable road user may carry
	      (e.g. smart phone, tablet, sensor tag).
	    </t>
            <t>
	      Assistance services that can improve traffic efficiency
	      by means of V2X communications, e.g. traffic sign
	      recognition and green light assistance.
	    </t>
	    <t>
	      Autonomous platooning
	      increase traffic flow and reduce fuel consumption and
	      emissions.
	    </t>
            <t>
	      Automated vehicles.
	    </t>
	  </list>	
	</t>

        <t>
	  To support the above use cases, METIS works out the
	  corresponding network requirements. For instance, for some
	  applications the E2E latency must be within 5ms;  other
	  requirements include data rates for various
	  scenarios, service ranges in highway/rural/urban
	  scenarios, etc.
	</t>
      </section>

    </section>

    <section anchor="iso" title="ISO perspective on V2V">
      <t>
	The International Standards Organization's Technical Committee
	204 "Intelligent transport systems" (ISO TC204, in short) has
	specified a communication architecture known as the "ITS
	station reference communication architecture" <xref
	target='ISO-21217'/>.  This communication architecture covers
	all protocol stack layers (access technologies, network, transport,
	facilities and applications).
	It is designed to accommodate communications
	between ITS stations engaged in ITS services.  ITS stations
	can be deployed in vehicles of any type, roadside
	infrastructure (traffic lights, variable message signs, toll
	road gantries, etc.), urban infrastructure (parking gates, bus
	stops, etc.)  nomadic devices (smartphones, tablets) and
	control centers (traffic control center, emergency call
	centers, data centers and services centers).  The ITS stations
	can be distributed in several nodes (e.g. an in-vehicle
	gateway and a set of hosts attached to the internal in-vehicle
	network).  The ITS station architecture is designed to support
	many kinds of wired and wireless access technologies
	(vehicular WiFi 802.11p, urban WiFi 802.11b/g/n/ac/ad;
	cellular networks; satellite; infra-red, LiFi, millimeter
	wave, etc.)
      </t>
      <t>
	The ISO ITS station architecture can thus support both
	broadcast and unicast types of communication,
	vehicle-to-infrastructure communications (road infrastructure
	using e.g. WiFi, or cellular infrastructure using e.g. 3G/4G)
	and, most notably, direct vehicle-to-vehicle communications.
      </t>
      <t>
	The architecture includes the possibility to communicate using
	IPv6 <xref target='ISO-21210'/> or non-IP (ISO FNTP, currently
	being harmonized with IEEE WAVE).
      </t>
      <t>
	The ISO TC204/WG14 (Work Group 14 "Vehicle/Roadway Warning and
	Control Systems") is developing a draft of international
	standard for C-ACC systems.  The focus is on vehicular system
	control, rather than on communication media.  The potential
	work item is in an early stage of development; it may describe
	performance requirements or validation through test
	procedures.  It is considered that "C-ACC" to be an expansion
	to the existing ACC concepts which have been previously
	described in the document ISO 15622 "Adaptive Cruise Control
	Systems".  The potential C-ACC work item may require the
	specific involvement of Vehicle-to-Vehicle communications and
	other types of communications (I2V and more), in addition to
	requiring active sensing involving radars and camera systems.
      </t>
    </section>

    <section title="ISO-IEEE Harmonization">
      <t>
	The intent is to harmonize the IEEE 1609 and ISO FAST
	protocols at 5.9GHz to avoid having to support
	region-dependent protocols (e.g. different protocols in Europe
	and the US), and this intention is not dependent on any
	particular application or service.
      </t>

      <t>
	The IEEE 1609.3 WG developed a version 3 draft of 1609.3 such
	that after publication of this version 3, and after subsequent
	appropriate updates of ISO 29281-1 and ISO 24102-5 an
	interoperability mode with ISO 29281-1 v2 FNTP and ISO 24102-5
	v2 FSAP will be given. This interoperability in the first step
	will be limited to broadcast of messages (e.g. for road
	safety) such that an ITS station unit can properly receive
	messages sent out by a WAVE device, and vice versa.
      </t>

      <t>
	C-ACC and Platooning are (C-)ITS services that will be
	deployed as ITS applications on ITS stations in vehicles.  These
	applications can and will make use of
	ITS station communication services (network and transport
	protocols, data link layer protocols, and physical layer
	protocols) that have the necessary characteristics/properties
	(e.g. V2V, low-latency, moderate bandwidth, etc.) to achieve
	their goals.  The IEEE 1609 and ISO protocols and
	communication services, whether or not they are ultimately
	"harmonized", can be used by either or both of these ITS
	applications as they generally meet the requirements for these
	apps.
      </t>

      <t>
	Some communication tasks in C-ACC and Platooning will use
	IPv6, whereas others will not.  For example some vendors of
	WAVE devices and ITS station units consider the use of the
	short messages protocol (not IPv6) for C-ACC and Platooning
	scenarios.
      </t>
    </section>

    <section anchor="itu" title="V2V communications at ITU">
      <t>
	The International Telecommunication Union (ITU) is the
	United Nations specialized agency for information and
	communication technologies.  It is an early standards
	development organization known for example, among other
	things, for spectrum or stationary orbit allocations to
	countries.
      </t>
      <t>
	Within ITU, the Telecommunication Standardization Sector
	(ITU-T) is composed of Study Groups (SGs) which make
	Recommendations which lead to standards for countries'
	Information and Communication Technologies (ICT) networks.
      </t>
      <t>
	The ITU-T SG 16 leads ITU's standardization work on multimedia
	coding and it is also the lead group for promissing topics
	such as the Internet of Things activities (IoT), Internet
	Protocol Television (IPTV) and Intelligent Transportation
	Systems (ITS).
      </t>
      <t>
	The Question 27/16 of ITU-T SG 16 titled "Vehicle gateway
	platform for telecommunication/ITS services/applications" is a
	group motivated by the observation that, among others, the
	information generated by vehicles has an important role in the
	chain of telecommunications and ITS.
      </t>
      <t>
	Currently under discussion, the proposed study items include
	the definition of a gateway (aka OBU) and the functions and
	requirements to support vehicle-to-vehicle and
	vehicle-to-intrastructure tellecommunications.  Another study
	item is to define scenarios for such gateways acting as
	bridges (presumably "IP routers" , Ed.) between cars and
	between cars and the infrastructure.
      </t>
      <t>
	The description of ITU-T Question 27/16 is publicly available
	on the web on the itu.int website.
      </t>
    </section>

    <section anchor="arib-its"
	    title="ARIB and ITS Info-comm use of CACC and V2V concepts">
      <t>
	In Japan, the Association of Radio Industries and Businesses
	(ARIB) and the ITS Info-communications Forum produce standards
	and guidelines for Intelligent Transportation Systems.
	Whereas US and EU standards focus mainly on the 5.9GHz bands
	for ITS, the Japanese standards operate initially in a 700MHz
	band.
      </t>
      <t>
	The publicly and freely available document RC-013 version 1.0
	titled "Experimental Guideline for Inter-Vehicle Communication
	Messages" considers that inter-vehicle communications
	(presumably V2V, Ed.) are realized with Basic Messages.  A
	Basic Message is generated by an application layer running on
	top of a "IVC-RVC" layer (at the typical network-layer place,
	Ed.) which runs itself on top of a Layer 2 "data-link" and of
	a Layer 1 PHY.  The contents of a Basic Message can be any one
	of the following: time information, position information,
	vehicle status, and more.  A particular data frame
	representing status information is the
	"DE_CooperativeAdaptiveCruiseControlStatus" represented on 2
	bits.
      </t>
    </section>
    
    <section anchor="firstnet"
	    title="FirstNet EMS use of LTE and IP in V2I2V">
      <t>
	FirstNet is a corporation housed inside the US Department of
	Commerce.  It gets capitalization budget from, among other
	sources, sale of spectrum by the US FCC.  It gets operating
	budget from sale of services to state emergency services
	entities.
      </t>

      <t>
	The communications architectures for FirstNet include
	vehicle-to-vehicle, vehicle-to-infrastructure and
	vehicle-to-infrastructure-to-vehicle communications using, in
	certain cases, LTE and IP:
	<list style='symbols'>
	  <t>
	    Emergency communications to vehicles from government
	    entities conveying, for example: weather warnings, road
	    conditions, evacuation orders.  The government entities
	    might include PSAPs or mobile vehicles such as police
	    cruisers.
	  </t>
          <t>
	    Instrumented emergency services vehicles such as
	    ambulances.  An example is the ability to telemeter
	    casualty (patient) data from sensors attached to the
	    casualty to a hospital emergency room.
	  </t>
	  <t>
	    Emergency communications from vehicles' occupants to
	    government entities such as Public Safety Access Points
	    (PSAPs, also known as 911 operators in US).
	  </t>
	</list>
      </t>

      <t>
	The National Public Safety Telecommunications Council
	describes FirstNet as an emergency communications system
	(largely viewed through the prism of the familiar Land Mobile
	Radio systems most emergency services use.)  The cellular
	telephone industry views FirstNet as supplementary to an
	existing commercial cellphone system (e.g. reusing the same
	towers and backhaul).  Perhaps a better view of FirstNet is as
	an extension of the Internet to emergency services vehicles
	(including pedestrian).
      </t>

      <t>
	It is clear that FirstNet overlaps with a large extent to the
	concepts that have been discussed in vehicle-to-vehicle
	communications for other purposes.
      </t>

      <t>
	FirstNet has not been clear about its communication technology
	choices to date.  But LTE has been discussed as the most
	likely layer 2 protocol.  A segregated segment of spectrum in
	the 700MHz band has been set aside by Congressional action for
	emergency services and control of that spectrum has been
	passed to FirstNet.  There appear to be no new protocols
	developed by FirstNet.  Several
	Internet applications would need rework to handle high
	availability, security and assured access needs of emergency
	services.
      </t>
<!--  CEP: noteworthy gap. -->

    </section>    

    <section anchor="apps" title="Internet apps: WAZE, iRezQ, Coyote, Sentinel">
      <t>
	Applications using the Internet have been developed in the
	particular context of vehicular communications.  These
	applications are designed for parties situated in
	vehicles.  Their profile is less of client-server kind, but
	more of peer-to-peer kind (vehicle to vehicle).
      </t>
      <t>
	Some use vehicle-to-infrastructure-to-vehicle IP paths,
	whereas others involve direct vehicle-to-vehicle paths
	(without infrastructure).
      </t>
      <t>
	These applications are described in more detail in a recent
	Internet Draft titled "Scenario of Intelligent Transportation
	System" <xref target="I-D.liu-its-scenario"/>.
      </t>
	  
    </section>

    <section anchor="car-mf-v2v-logos"
	    title="Car manufacturer labels with V2V features">
      <t>

	Toyota "ITS Connect" is a feature advertised for high-end
	automobile models set to hit the roads by the end of 2015.
	This includes the Crown as well as two other lower level
	models.  The "ITS Connect" features which exhibit V2V
	characteristics are Right Turn Collision Caution, Red Light
	Caution and Emergency Vehicle Proximity Notification.  One
	particular V2V feature which illustrates a possible migration
	from exclusively radar signals to bidirectional data exchanges
	is the Communicating Radar Cruise Control.  A publicly
	available description of this feature mentions that it
	integrates Radar Cruise Control and V2V information from the
	preceding vehicle to help follow it smoothly.  Toyota "ITS
	Connect" is using Japanese ARIB standards STD-Txxx and ITS
	Info-communications Forum Guidelines RC-xxx in the 700MHz
	band.
      </t>
    </section>

    <section anchor="gap" title="Gap Analysis">
      <t>
	It is generally agreed that one or more IP subnets are embedded
	in an automobile.  The embedded network is formed by at least
	two (and generally up to 5) distinct IP subnets.  In each of
	the subnets several IP-addressable computers are currently
	enabled with IP stacks.
      </t>
      <t>
	The realization of V2V communications can happen by connecting
	together two such embedded networks, each carried by a
	distinct vehicle.  With a direct connection, an IP Router in
	one vehicle connects to an IP Router in another vehicle
	nearby.  The maximum distance between two such vehicles is
	dictated by the link layer technology (e.g., with IEEE 802.11p
	OCB mode the distance may be up to 800 metres).  On another
	hand, an indirect connection may involve the use of a
	Road-Side Unit, or a longer IP path
	through a cellular network.  It is expected that the shortest
	latencies to be obtained with the most straightforward
	(direct) connections rather than through-fixed-RSU
	through-cellular.
      </t>
      <t>
	When two vehicles are connected to each other in this way, an
	IP subnet is formed between the egress interfaces of Router
	embedded in vehicles.  There are several ways in which the IP
	path can be established across this 1-hop subnet.
      </t>
      <section title="Neighbor Discovery protocol">
	<t>
	  Routers exchange Router Advertisement messages.  An RA
	  message contains prefixes announced to be valid on one link.
	  On another hand, the prefix announced by an RA can not be
	  equal to the prefix of a same router but of one of its other
	  interfaces.  And this represents a shortcoming of the ND protocol
	  - it can not support V2V topologies.
	</t>
      </section>
      <section title="Mobile IP protocol">
	<t>
	  There are two modes of operation of a V2V topology.  With a
	  link technology like IEEE 802.11b it is possible that one
	  vehicle attaches to another vehicle in "Access Point" mode,
	  or alternatively in "ad-hoc" mode.  In "Access Point" mode
	  (or Client-Server), the first vehicle allocates an address,
	  and potentially a prefix, to the second vehicle.  This
	  latter may then use the Mobile IP protocol to inform the
	  first vehicle about in-car prefix (use a Binding Update
	  message as if the Access Point vehicle were a Correspondent
	  Node).  The gap is in that currently the Mobile IP protocol
	  is not fully specified to send BUs in that way.
	</t>
	<t>
	  This Mobile IP gap depends largely on the situation
	  (physical location) of the Home Agent entity.  The placement
	  of the Home Agent in the fixed infrastructure is assumed by
	  the most common deployments of connected vehicles.  The Home
	  Agent in charge of the vehicle is situated in a data center
	  owned and administered by the vehicle manufacturer.  Other
	  similar placements consider the fixed network of a regional
	  representative of the manufacturer, or a local dealer.
	  Further, in theory, it can be considered that a Home Agent
	  be placed inside a vehicle as well, although this has not
	  been tested.  Depending on this placement of the HA, the
	  Mobile IP gap can vary.
	</t>
	<t>
	  Note a new requirement has been developped recently in the
	  DMM Working Group.  The distributed mobility management
	  requirement REQ1 in <xref target="RFC7333"/> states that DMM
	  solutions must enable traffic to avoid traversing a single
	  mobility anchor far from the optimal route.  This may help
	  placing a Home Agent nearer to the access network (rather
	  than in a data center).  In addition to this requirement, it
	  may be necessary to dynamically migrate the Home Agent to a
	  place near the vehicle, as it moves across borders or travel
	  long distances.
	</t>
      </section>
      <section title="AODVv2 protocol">
	<t>
	  The AODVv2 protocol <xref target="I-D.ietf-manet-aodvv2"/>
	  is a routing protocol used to build and find IP paths in an
	  ad hoc network.  However, AODVv2 does not take into account
	  preconfiguration of default routes.  Default routes are
	  extensively used in current networks carried in vehicles.
	  Good administration of default routes can greatly simplify
	  routing in such networks.  This represents a gap.
	</t>
      </section>

    </section>

    <section anchor="Security" title="Security Considerations">
      <t>
	All government-to-vehicle and vehicle-to-government
	communications, without exception, require authentication.
      </t>

      <t>
	Some, but not all, communications from government-to-vehicle
	and vehicle-to-government require confidentiality to protect
	the content of the messages.  Some of
	these requirements, such as medical data, have the force of
	law. Others are customary, or are based on common respect as
	requirements.
      </t>

      <t>
	Protocol information shared between the cooperating vehicles
	MUST also be protected in order to avoid disruption or
	attack on the vehicles operation.  Any modification or
	malicious insertion of protocol messages would carry with
	it a high risk of death and injury as well as tremendous
	disruption of other vehicular traffic.
      </t>

    </section>
    

    <section anchor="IANA" title="IANA Considerations">
      <t>
	mandatory
      </t>
    </section>

    <section anchor="Contributors"
	     title="Contributors">
      <t>
	Jim Misener (Qualcomm, SAE DSRC TC Chair), Masanori Misumi
	(Mazda, ISO TC204/WG14 Convenor), Michelle Wetterwald
	(Consult Europe), Tom Kurihara (mindspring).
      </t>
    </section>

    <!-- <section anchor="Acknowledgements" -->
    <!-- 	     title="Acknowledgements"> -->
    <!--   <t> -->
    <!-- 	The authors would like to acknowledge . -->
    <!--   </t> -->
    <!-- </section> -->
    
  </middle>

  <!--  *****BACK MATTER ***** -->

  <back>

    <references title="Normative References">
      &RFC2119;
      &RFC7333;
    </references>

    <references title="Informative References">
      &DRAFT-IPv6-over-11p;
      &DRAFT-liu-its-scenario;
      &DRAFT-ietf-manet-aodvv2;

      <reference anchor='CACC-def'>
        <front>
          <title>
	    Cooperative Adaptive Cruise Control (CACC) Definitions and
	    Operating Concepts
	  </title>

          <author initials='E.' surname='Shladover'
		  fullname='Steven Shladover'>
            <organization>
	      California PATH, UC Berkeley
	    </organization>
          </author>

          <author initials='C.' surname='Nowakowski' 
		  fullname='Christopher Nowakowski'>
            <organization>
	      California PATH, UC Berkeley
	    </organization>
          </author>

	  <author initials='X-Y.' surname='Lu' 
		  fullname='Xiao-Yun Lu'>
            <organization>
	      California PATH, UC Berkeley
	    </organization>
          </author>

	  <author initials='X-Y.' surname='Ferlis' 
		  fullname='Robert Ferlis'>
            <organization>
	      Federal Highway Administration
	    </organization>
          </author>
	  
          <date year='2015' month='April' />
        </front>

        <format type="PDF"
		target='http://www.researchgate.net/publication/273204405_COOPERATIVE_ADAPTIVE_CRUISE_CONTROL_%28CACC%29_DEFINITIONS_AND_OPERATING_CONCEPTS' />
      </reference>

      <reference anchor='ACC-def'>
        <front>
          <title>
	    Optimal Adaptive Cruise Control with Guaranteed String
	    Stability
	  </title>

          <author initials='C-Y.' surname='Liang'
		  fullname='Chi-Ying Liang'>
            <organization>
	      Uni Michigan
	    </organization>
          </author>

          <author initials='H.' surname='Peng' 
		  fullname='Huei'>
            <organization>
	      Uni Michigan
	    </organization>
          </author>
          <date year='1999' month='April' />
        </front>

        <format type="PDF"
		target='http://www-personal.umich.edu/~hpeng/VSD_1999_Liang.pdf' />
      </reference>

      <reference anchor='METIS-D1.1'>
        <front>
          <title>
	    Scenarios, requirements and KPIs for 5G mobile and
	    wireless system
	  </title>

          <author initials='M.' surname='Fallgren'
		  fullname='Mikael Fallgren'>
            <organization>
	      Ericsson AB
	    </organization>
          </author>

          <author initials='B.' surname='Timus' fullname='Bogdan Timus'>
            <organization>
	      Ericsson AB
	    </organization>
          </author>
	  
          <date year='2013' month='April' />
        </front>
      </reference>

      <reference anchor="ETSI-CACC">
        <front>
          <title>
	    Cooperative Adaptive Cruise Control (C-ACC)
	    prestandardization study (ETSI-SAE join WI proposal);
	    ongoing at the time of writing of this Internet Draft
	  </title>
          <author initials='' surname='' fullname=''>
            <organization>
	      ETSI Technical Report TR 103 299
	    </organization>
          </author>
          <date year='2015' />
        </front>
      </reference>

      <reference anchor="SAE-V2V">
        <front>
          <title>
	    On-board System Requirements for V2V Safety Communications
	  </title>
          <author initials='' surname='' fullname=''>
            <organization>
	      SAE International (Society for Automotive Engineering),
	      J2945/1; ongoing work at the time of writing this
	      Internet Draft.
	    </organization>
          </author>
          <date year='2015' />
        </front>
      </reference>

      <reference anchor="ISO-CACC">
        <front>
          <title>
	    PWI 20035 Intelligent Transport Systems - Cooperative
	    Adaptive Cruise Control Systems (CACC) - Performance
	    requirements and test procedures, Reference number 20035;
	    ongoing work at the time of writing of this Internet
	    Draft.
	  </title>
          <author initials='' surname='' fullname=''>
            <organization>
	      ISO
	    </organization>
          </author>
          <date year='2015' />
        </front>
      </reference>

      <reference anchor="ITU-V2V">
        <front>
          <title>
	    Question 27/16 - Vehicle gateway platform for
	    telecommunications/ITS services/applications; ongoing work
	    at the time of writing this Internet Draft.
	  </title>
          <author initials='' surname='' fullname=''>
            <organization>
	      ITU
	    </organization>
          </author>
          <date year='2015' />
        </front>
      </reference>

      <reference anchor="its-infocomm-CACC">
        <front>
          <title>
	    Experimental Guideline for Inter-vehicle Communication
	    Messages; ITS Forum RC-013 Ver. 1.0
	  </title>
          <author initials='' surname='' fullname=''>
            <organization>
	      ITS Info-communications Forum of Japan
	    </organization>
          </author>
          <date year='2014' />
        </front>
      </reference>


      <reference anchor="GPP-TR-22-803">
        <front>
          <title>
	    Feasibility study for Proximity Services (ProSe)
	  </title>
          <author initials='' surname='' fullname=''>
            <organization>
	      3GPP
	    </organization>
          </author>
          <date year='2013' month='June' />
        </front>

        <format type="zip"
		target='http://www.3gpp.org/ftp/specs/archive/22_series/22.803/22803-c20.zip' />
      </reference>

      <reference anchor='GPP-TS-22-278'>
        <front>
          <title>
	    Service requirements for the Evolved Packet System (EPS)
	  </title>
          <author initials='' surname='' fullname=''>
            <organization>
	      3GPP
	    </organization>
          </author>
	  
          <date year='2014' month='December' />
        </front>
        <format type="zip"
		target='http://www.3gpp.org/ftp/specs/archive/22_series/22.278/22278-d20.zip' />
      </reference>

      <reference anchor='GPP-TR-22-885'>
        <front>
          <title>
	    Study on LTE Support for V2X Services
	  </title>
          <author initials='' surname='' fullname=''>
            <organization>
	      3GPP
	    </organization>
          </author>
	  
          <date year='2015' month='April' />
        </front>
        <format type=""
		target='' />
      </reference>

      <reference anchor='ISO-21217'>
        <front>
          <title>
	    21217: TC ITS - WG CALM - Architecture -
	    International Standard
	  </title>
          <author initials='' surname='' fullname=''>
            <organization>
	      ISO
	    </organization>
          </author>
	  
          <date year='2014' month='' />
        </front>
        <format type=""
		target='http://www.iso.org/iso/catalogue_detail.htm?csnumber=61570' />
      </reference>

      <reference anchor='ISO-21210'>
        <front>
          <title>
	    21210: TC ITS - WG CALM - IPv6 Networking -
	    International Standard
	  </title>
          <author initials='' surname='' fullname=''>
            <organization>
	      ISO
	    </organization>
          </author>
	  
          <date year='2014' month='' />
        </front>
        <format type=""
		target='http://www.iso.org/iso/catalogue_detail.htm?csnumber=46549' />
      </reference>      

    </references>


    <section anchor='changelog'
	     title='ChangeLog'>
      <t>
	The changes are listed in reverse chronological order, most
	recent changes appearing at the top of the list.
      </t>

      <t>
	From -04 to -05:
	<list style='symbols'>
	  <t>
	    Minor updates.
	  </t>
	</list>	
      </t>
      <t>
	From -03 to -04:
	<list style='symbols'>
	  <t>
	    Updated the perspective from SAE with respect to work on
	    V2V requirements for safety.
	  </t>
	  <t>
	    Clarified the IEEE 1609 point of view by which C-ACC use
	    IEEE 1609 protocols.
	  </t>
	  <t>
	    Added authors' point of view of IEEE-ISO harmonization,
	    which may have a relationship to vehicle-to-vehicle
	    communications.
	  </t>
	  <t>
	    Added ITU-T Question 27 of Study Group 16 description
	    mentioning V2V communications.
	  </t>
	  <t>
	    Added a section on Japan's ARIB and ITS info-comm
	    documents which describe C-ACC and other inter-vehicle
	    services in the 700MHz band.  Added an example of car
	    manufacturer with product on the market at the time of
	    writing implementing some of these features.
	  </t>
	  <t>
	    Clarification of HA placement conditioning the Mobile IP
	    gap discussion.
	  </t>
	  <t>
	    Editorial improvements, citations added, terminology
	    section improved.
	  </t>
	</list>	
      </t>

      <t>
	From -01 to -02:
	<list style='symbols'>
	  <t>
	    Added perspectives on C-ACC and Platooning from ETSI, SAE,
	    and IEEE P1609.  Updated the perspective from ISO.
	  </t>
	  <t>
	    Added Gap Analysis: what are the gaps between what
	    existing protocols ND, Mobile IP and AODV can do and what
	    is needed to realize a C-ACC and Platooning use-case with
	    a V2V topology?
	  </t>
	</list>	
      </t>
      
    </section>

  </back>
</rfc>

PAFTECH AB 2003-20262026-04-23 16:29:08