TSN network prototype for in-vehicle communications (Part 1) | Prototype overview

Time-sensitive networking (TSN) technology is one of the key technologies for achieving high reliability and low latency in vehicle network communications. The TSN protocol family is very large and complex, and a comprehensive understanding and mastery of these protocols is a common problem faced by designers; in addition, in the field of vehicle network communications, the automotive industry lacks practical experience in the application of TSN technology. Therefore, methods such as related technical design application, test verification, etc. need to be further explored.

In the process of rapid implementation of new technologies, proof of concept (POC) or building a system prototype is a common method. The higher the degree of restoration of the system prototype to the actual system, the more sufficient the feasibility and necessity of subsequent new technologies can be verified, and finally the engineering application of actual projects can be achieved. At the same time, it has the characteristics of low project risk and low sunk cost.

Norinco is committed to providing comprehensive and mature in-vehicle TSN network communication application solutions to automotive customers, mainly covering engineering service areas such as TSN technology design, simulation, prototype construction, test verification and tool chain application.

This article will focus on the engineering services related to TSN network prototype construction provided by Norinco Information based on customer customized requirements.

01Centralized Architecture Communication Application Scenario

The centralized architecture is the ultimate goal of automotive electronic architecture. The on-board electronic system is a typical distributed real-time system that needs to meet functional requirements such as hard real-time, soft real-time and strict real-time.

Therefore, the network communication architecture in the new architecture will have the following characteristics:

Network architecture features

Access layer: rich network port types and sufficient resources; Aggregation layer: mostly adopts ring network design to achieve high reliability; Core layer: specific implementation is related to the HPC hardware platform;

Data flow characteristics

Sensor data: Sensor -> HPC; Control instructions: HPC -> Actuator; Software process data interaction: between distributed systems;
02 PoleLink TSN prototype
Beihui Information has built a set of TSN network prototypes, aiming to show the engineering application role and effect of TSN technology in vehicle networks in a visual way. At the same time, it takes into account the constraints of the self-driving system on the QoS of network communication and the feasibility verification requirements of the DDS-TSN basic software architecture. 03 Network prototype topology design


04 Communication application scenario implementation The network prototype covers typical network communication application scenarios of the central architecture, as shown below:

Time synchronization scenario

Time synchronization of network nodes or devices such as LiDAR, Camera, Switch, etc.

QoS constraints for network transmission of critical and important data flows

Sensor data transmission Sensor -> HPC: Camera video stream uses CBS shaping

Sensor data transmission Sensor -> HPC: LiDAR point cloud data stream uses TAS shaping

Control data transmission HPC -> Actuator: HPC headlight control flow uses TAS shaping

Ethernet Ring Network Design

HPC headlight control flow uses CB to achieve network link redundancy

LiDAR point cloud data stream uses CB to achieve network link redundancy

05
Communication data flow definition
06
Communication protocol application
The main network communication protocols involved in the prototype system are as follows:

TSN protocol

gPTP, Qav, Qbv, CB, 1722

Other communication protocols

DDS

07 Prototype System Hardware List

08Prototype Panoramic Display
09Conclusion

The TSN network prototype uses TSN protocols such as gPTP, Qav, Qbv, CB, 1722, and the DDS upper-layer communication protocol; it comprehensively considers the network communication application scenarios in the central architecture, selects representative data streams in the network communication architecture, and completes the TSN technology design and application scenario implementation.

Among them, the network data flow characteristics and quantity of the TSN network prototype, the application scope of the TSN protocol, the hardware selection of sensors, actuators, TSN switches, etc. can be adjusted and adapted according to the network topology and data transmission requirements of the actual project.