GB/T 31024.3-2019Cooperative intelligent transportation systems—Dedicated short range communications—Part 3:Network layer and application layer specification (English PDF)

3.1 Dedicated short range communication

wireless communication method for short range communication among traffic elements such as vehicles, infrastructures and pedestrians

3.2 Dedicated short range communication management entity

a universal set of dedicated short range communication management services that provides management interfaces for all data layer entities

3.3 Management information base

an entity used to store application configuration and status information

5.1 Network layer framework

The DSRC network layer framework of cooperative intelligent transportation system is shown in Figure 1.

5.2 Technical requirements of data sublayer

5.2.1 General

The data sublayer in the DSRC network layer of the cooperative intelligent transportation system comprises TCP/UDP, IP, DSMP and adaptation layer, wherein the IP protocol and the TCP/UDP protocol are not within the definition of this part.

5.2.2 Adaptation layer

The adaptation layer provides the transmission adaptation function between the underlying access technology and the upper layer protocol stack. The adaptation layer receives the DSMP data packet, the IP data packet, or the DME data packet sent by the upper layer, distinguishes the underlying access technology used by the data packet to be sent, and delivers the corresponding data packet to the bottom layer in line with the corresponding access technology for transmission;

5.2.3 DSMP

5.2.3.1 DSM data frame format

The layer-by-layer packaging process of DSM is shown in Figure 5.

5.3 Technical requirements of management sublayer

5.3.1 Application registration

Before using management sublayer services, the application needs to be registered with the DME first. An application running on a DSRC device needs to be registered as a user application, so that the DME can send the received DSM to the corresponding application.

5.3.2 Service management

Service management belongs to the internal operation of the device, and the corresponding functions are optional. When an application issues a service usage request to the DME, the DME will initialize the requested service. An example of the service management process is shown in Figure 7.

5.3.3 MIB maintenance

The MIB operation process is shown in Figure 8. The MIB is responsible for management and maintenance of the application configuration and status information of the DSRC modules of the cooperative intelligent transportation system. The DME sets and queries the MIB information through specified signaling. After receiving a service request message, the DME establishes a MIB information table corresponding to the service in the MIB.

5.4 Access point and service primitive

5.4.1 Service Access Point (SAP)

The SAP of the DSRC network layer is shown in Figure 10.

5.4.2 Access layer service primitive

5.4.2.1 ACCESS-LAYER.request

ACCESS-LAYER.request is used to send the access data requested by the upper layer.

Service primitive parameters: given in the underlying standard.

5.4.2.2 ACCESS-LAYER.indication

ACCESS-LAYER.indication is used to indicate that the upper layer has received the access data.

5.4.3 Adaptation layer service primitive

5.4.3.1 ADAPTATION-LAYER.request

ADAPTATION-LAYER.request is used to send the adaptation layer data requested by the upper layer.

5.4.4 DSM service primitive

5.4.4.1 DSM.request

DSM.request is used by the upper layer to request to send the DSM data.

Service primitive parameters: The DSM.request service primitive parameters are shown in Table 11.

6.1 Basic requirements

Interactive data set of application layer is defined according to ASN.1, its basic notation specification is based on GB/T 16262.1, information object specification is based on GB/T 16262.2, constraint specification is based on GB/T 16262.3, and parameterization of ASN.1 specifications is based on GB/T 16262.4.

The encoding method of interactive data set of application layer is defined according to GB/T 16263.2, adopting Unaligned Packet Encoding Rules (UPER).

6.2 Definition of data set

6.2.1 General

The interactive data set of application layer is established by following the multilevel nested logic of "message set-data frame-data element".

The message set is packaged in a uniform frame format, as a basic unit of application layer interaction. This part defines five message types, with each message consisting of the combination of data frame and data element.

6.2.2 Message set

6.2.2.1 General provisions

The message set consists of frame format and packaged message body in the frame.

6.2.3 Data frame

6.2.3.1 General provisions

The data frame is substantial information combination, composed of other data frames or data units.

6.2.3.2 DF_AccelerationSet4Way

It defines the 4-axis acceleration of the vehicle. Specific contents are as follows. […]

6.2.3.3 DF_BrakeSystemStatus

It defines the brake system status of the vehicle, including the following 7 different types of status.

6.2.3.4 DF_ConnectingLane

It defines the downstream lane to which a lane at the intersection connects, including downstream lane ID and the allowable driving behavior at the turning.

6.2.3.5 DF_Connection

It defines the connection between the lane at the intersection and the lane in the downstream link. The exit node ID of downstream link, the basic information of connecting lane in the downstream link, and the corresponding signal phase No. are included.

6.2.3.6 DF_ConnectsToList

It defines the list of connection between the turnings of each lane at the intersection and of the lane in the downstream link.

6.2.3.43 DF_positionConfidenceSet

It defines the comprehensive confidence of the position (latitude, longitude and elevation).

6.2.3.44 DF_PositionOffsetLL

It defines latitude and longitude offset, which is used for describing the relative position of a coordinate point. 7 description modes of dimension are provided.

6.2.3.45 DF_PositionOffsetLLV

It defines three-dimensional relative position offset (relative latitude, relative longitude and relative elevation).

6.2.3.46 DF_RegulatorySpeedLimit

It defines speed limit attribute, including speed limit type and the specified speed limit value.

6.2.3.47 DF_RoadPoint

It defines a position point marked on road, which is described by relative position.

6.2.3.48 DF_SignalState

It defines the attribute and current state of one intersection signal light, including the current working mode, current time stamp and real-time phase information list of this signal light.

6.2.3.49 DF_SpeedLimitList

It defines the speed link list of the link or lane.

6.2.3.50 DF_TimeChangeDetails

It defines a complete timing attribute of the phase state of a signal light.

The specific parameters of the data frame have the following meanings.

6.2.3.51 DF_VehicleClassification

It defines the basic vehicle classification.

6.2.3.52 DF_VehicleSafetyExtensions

It defines the set of vehicle safety extension information, which is used as a supplement for the basic safety data in Msg_BSM message, including vehicle special event states, vehicle path history, path prediction, exterior light states, etc. Each extension information is optional.

6.2.3.53 DF_VehicleSize

It defines the vehicle size according to the vehicle length, width and height. Thereinto, the height value is optional.

6.2.3.54 DF_VerticalOffset

It defines the vertical positional offset, and provides 7 modes for expressing the offset of dimension range.

6.2.4 Data elements

6.2.4.1 General provisions

Data elements are part of message bodies or data frames, which is generated by basic data type definition and has actual physical significance.

Considering the consistency with international standards, some data elements are defined with reference to SAE J2735 and SAE J2945/1.

6.2.4.2 DE_Acceleration

It defines the acceleration of vehicle. The resolution is 0.01 m/s² and the range is -2 000 to 2 001, where the value 2 001 indicates an invalid value.

6.2.4.3 DE_AlertType

It defines the type of roadside alert information Msg_RSI. The range of values is 0-65 535, and the value 0 indicates the text description information. The value greater than 0 indicates traffic sign information, which is defined according to GB 5768.2.

6.2.4.4 DE_AllowedManeuvers

It defines the allowed steering maneuvers of (motor vehicle) lane.

6.2.4.5 DE_AntiLockBrakeStatus

It defines the status of Anti-lock Braking System.

6.2.4.6 DE_AuxiliaryBrakeStatus

It indicates the status of Auxiliary Brake System (generally is handbrake). […]