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SAE J2735-Draft-Rev15 [issued: 01-30-07]
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This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
3.30 message set: A collection of messages based on the ITS functional-area they pertain to. This DSRC
standard is also a message set.
3.31 message set extender: The concept of a message set extender refers to the process of adding additional
data elements to a common (non-changing) core message in order to extend the basic core message structure to
create messages for specific applications needs.
3.32 metadata: Data that defines and describes other data.
3.33 networking services: The collection of management plane and data plane function at the network layer and
transport layer, supporting WAVE communications.
3.34 notification: An indication of an event of interest, sent to an application.
3.35 OBU to vehicle host interface (OVHI): Interface on the OBU offering access to WAVE capabilities by other
vehicle-based devices.
3.36 on-board unit: An On-Board Unit (OBU) is a vehicle mounted DSRC device used to transmit and receive a
variety of message traffic to and from other DSRC devices (other OBUs and RSUs). Among the message types
and applications supported by this process are vehicle safety messages, a primary subject of this standard, used
to exchange information on each vehicle's dynamic movements for coordination and safety.
3.37 operations: One of three modes, or states, of operation known as Registration, Initialization, and Operations
which DSRC systems operate in. In the Operations mode a link has been established, the link will have an open
socket with which it can conduct operations in the same manner as with any other 802.11 communications
session. The lower layers will be managing the switching between the Control Channel and the Service Channel.
When the radio has switched to another channel, it would appear to the application as a temporary loss of
communications.
3.38 provider service table: The collection of data describing the applications that are registered with a WAVE
device.
3.39 registration: One of three modes, or states, of operation known as Registration, Initialization, and Operations
which DSRC systems operate in. The Registration mode is the process by which critical parameters pertaining to
the device and applications using it are entered into the device's Management Information Base (MIB). Registration
must be completed before a DSRC device can be ready for operations. The registration process is defined in IEEE
P1609.3 and is controlled by the WAVE Management Entity (WME).
3.40 road side unit: A Road Side Unit (RSU) is a DSRC device used to transmit to, and receive from, DSRC
equipped moving vehicles (OBUs). The RSU transmits from a fixed position on the roadside (which may in fact be
a permanent installation or from "temporary" equipment brought on-site for a period of time associated with an
incident, road construction, or other event). RSUs have the ability to transmit signals with greater power than
OBUs and may have TCIP/IP connectivity to other nodes or the Internet.
3.41 service channel: Secondary channels used for application-specific information exchanges.
3.42 service table: A data store containing the pertinent information about applications available through the
WAVE device.
3.43 stability control: A system which operates to prevent a car from sliding sideways under dynamic driving
conditions.
3.44 station: Any device that contains an IEEE 802.11 conformant medium access control (MAC) and physical
layer (PHY) interface to the wireless medium. An RSU and OBU are stations.
3.45 syntax: The structure of expressions in a language, and the rules governing the structure of a language.
3.46 transactions: Bi-directional data exchanges between devices (RSUs and OBUs).