 |
 |
 |
 |
|
 |
 |
SAE J2735-Draft-Rev29 [issued: 12-11-08]
-
69 -
This is an SAE Motor Vehicle Council draft document of the DSRC committee, subject to change.
Remarks: Note that both a preempt to a signal system and a priority for a signal system are described in
the same terms here. The term signal control zone was created to cover both uses.
6.38 Data Frame: DF_SignalRequest
Use: The SignalRequest is used (as part of a request message) to request either a priority or a preemption
service from a signalized intersection. It relates the intersection ID as well as the specific request (a value
of 0~7 for the request and a value of 0~7 for the strategy requested - both in the SignalReqScheme data
element). Additional information includes the approach and egress values or lanes to be used.
ASN.1 Representation:
SignalRequest ::= SEQUENCE {
-- the regionally unique ID of the target intersection
id IntersectionID, -- intersection ID
-- Below present only when canceling a prior request
isCancel SignalReqScheme OPTIONAL,
-- In typical use either a SignalReqScheme
-- or a lane number would be given, this
-- indicates the scheme to use or the
-- path through the intersection
-- to the degree it is known.
-- Note that SignalReqScheme can hold either
-- a preempt or a priority value.
requestedActon SignalReqScheme OPTIONAL,
-- preempt ID or the
-- priority ID
-- (and strategy)
inLane LaneNumber OPTIONAL,
-- approach Lane
outLane LaneNumber OPTIONAL,
-- egress Lane
type NTCIPVehicleclass,
-- Two 4 bit nibbles as:
-- NTCIP vehicle class type
-- NTCIP vehicle class level
-- any validation string used by the system
codeWord CodeWord OPTIONAL,
...
}
XML Representation:
<xs:complexType name="SignalRequest" >
<xs:sequence>
<!-- the regionally unique ID of the target intersection -->
<xs:element name="id" type="IntersectionID" />
<!-- intersection ID
Below present only when canceling a prior request -->
<xs:element name="isCancel" type="SignalReqScheme" minOccurs="0"/>
<!-- In typical use either a SignalReqScheme
or a lane number would be given, this
indicates the scheme to use or the
path through the intersection
to the degree it is known.
Note that SignalReqScheme can hold either
a preempt or a priority value. -->
<xs:element name="requestedActon" type="SignalReqScheme" minOccurs="0"/>
<!-- preempt ID or the
priority ID
(and strategy) -->
<xs:element name="inLane" type="LaneNumber" minOccurs="0"/>
<!-- approach Lane -->
<xs:element name="outLane" type="LaneNumber" minOccurs="0"/>
<!-- egress Lane -->