(Informative)
To enhance its own capabilities to perceive the Environment, a CAV exchanges information via radio with other entities, e.g., Remote AMSs may be achieved via secure channels.
V2X is the CAV component that allows the CAV Subsystems – Human-CAV Interaction and Autonomous Motion Subsystems – to communicate to peer entities external to the Ego CAV. For instance, the HCI of a CAV may send/request information to/from the HCI of another CAV or an AMS may send/request the BER to/from the AMS of another CAV.
2.3 Other non-CAV vehicles. 27
1 V2X Communication
V2X may be achieved via different communication protocols. A CAV may use multicast or unicast to send CAVs in range information it has become aware of by using the V2X communication interface. For instance, while executing a Command, the MAS of CAV may become aware of ice on the road. The AMS may decide to broadcast that information to CAVs in range. Unicast may be used for communication between the Ego CAV and a specific CAV.
Multicast Communication may be used when a CAV broadcasts large amounts of data such as the Basic Environment Representation (BER). The BER data format should be scalable to enable transmission of the more important elements of the BER in case the number of CAVs is large.
Communication with Remote CAVs is managed by a Communication Device. Here is an example of the operation flow of the Communication Device communicating with Remote CAVs:
- Receive identities broadcasted by Remote AMSs.
- Establish unicast sessions with Remote AMSs.
- Create a list of Remote CAVs with which it has established a session.
- Sends the Ego CAV’s information to Remote AMSs.
2 Input and output data
2.1 CAVs within range
Table 15 gives the Data Types a CAV broadcasts to CAVs in range via its Communication Device.
Table 15 – I/O data of CAV’s Communication Device
| Input Data | From | Comments |
| CAV Identity | Remote AMSs | In principle, this should be the digital equivalent of today’s plate number including Manufacturer and Model information. |
| Basic Environment Representation | Remote AMSs | A scalable subset of the digital representation of the Environment created by the ESS. |
| Information Messages | Remote AMSs and/or HCIs | Possible messages received by a CAV: 1. CAV is an ambulance. 2. CAV carries an authority. 3. CAV carries a passenger with critical health problem. 4. CAV has a mechanical problem of an identified level. 5. Works and traffic jams ahead 6. Environment must be evacuated. 7. … |
| Output Data | To | Comments |
| CAV Identity | Remote AMSs | In principle, this should be the digital equivalent of today’s plate number including Manufacturer and Model information. |
| Basic Environment Representation | Remote AMSs | Same as input for all other input data. BER accuracy depends on available bandwidth. |
| Information Messages | Remote AMSs and/or HCIs | Typical messages as above. |
2.2 CAV-aware equipment
Examples are traffic lights, roadside units, and vehicles with CAV communication capabilities. The following data may be included in an exchange between CAVs:
- Identity and Spatial Attitude.
- Static Full Environment Representation that is regularly updated.
- State (Green-Yellow-Red) of traffic light and time to change state.
- Lane markings.
- Speed limits.
- Pedestrian crosswalks.
- General information on the Environment (e.g., one way street etc.)
CAV-aware equipment:
- Can act as any other CAV in range.
- May have the authority to organise motion of CAVs in range.
2.3 Other non-CAV vehicles
Other vehicles can be scooters, motorcycles, bicycles, etc. possibly transmitting their position as derived from GNSS. No response capability is expected. Vehicles may also have the capability to transmit additional information, e.g., identity, model, speed.
2.4 Pedestrians
Their smartphones can transmit their Spatial Attitudes. No response capability is expected.
