Time-Sensitive Networking for Automotive In-Vehicle Networks

Modern vehicles are becoming increasingly complex, with dozens of electronic control units (ECUs) that need to communicate with each other in real-time. Time-Sensitive Networking (TSN) provides the deterministic communication infrastructure needed for advanced driver assistance systems (ADAS) and autonomous driving functions.

Key Challenges in Automotive Networks

Mixed-criticality traffic: Handling both safety-critical and non-critical traffic on the same network
Ultra-low latency requirements: Ensuring sensor data reaches control units within microsecond precision
High reliability: Maintaining communication even in the presence of faults
Bandwidth efficiency: Managing increasing data rates from cameras, lidars, and radars
Cost-effectiveness: Replacing multiple specialized networks with a single Ethernet-based network

TSN Features for Automotive Applications

Time Synchronization (IEEE 802.1AS)

Precise time synchronization is essential for coordinating distributed automotive systems. OMNEST simulations can model the gPTP (generalized Precision Time Protocol) to achieve sub-microsecond synchronization across the in-vehicle network.

INET TSN Time Synchronization Showcase

Scheduled Traffic (IEEE 802.1Qbv)

Time-aware shapers enable deterministic transmission of critical traffic by scheduling network access using gate control lists. This ensures that high-priority traffic (like steering or braking commands) is transmitted without interference from lower-priority traffic.

INET TSN Scheduled Traffic Showcase

Frame Preemption (IEEE 802.1Qbu and IEEE 802.3br)

When high-priority frames need immediate transmission, frame preemption allows them to interrupt the transmission of lower-priority frames, further reducing latency for critical traffic.

INET TSN Frame Preemption Showcase

Redundancy with Frame Replication and Elimination (IEEE 802.1CB)

For safety-critical systems like steering and braking, redundant paths ensure that data arrives even if one path fails. Frame replication sends duplicate packets over different paths, while frame elimination removes duplicates at the receiver.

INET TSN Redundancy Showcase

Automotive Use Cases

Autonomous Driving

TSN enables reliable communication between sensors (cameras, lidars, radars), fusion units, and control systems with guaranteed latency bounds, essential for real-time decision making in autonomous vehicles.

Advanced Driver Assistance Systems (ADAS)

Features like automatic emergency braking, adaptive cruise control, and lane keeping assistance rely on deterministic communication to ensure timely response to changing road conditions.

Domain Controllers

Modern vehicle architectures are moving toward domain controllers that consolidate multiple functions. TSN provides the communication backbone between these controllers, ensuring that each domain (powertrain, chassis, infotainment, etc.) receives the data it needs with appropriate timing guarantees.

Simulation Capabilities with OMNEST

OMNEST's TSN simulation capabilities allow you to:

Network topology design: Model complex in-vehicle network topologies with multiple switches and end devices
Traffic pattern analysis: Simulate realistic automotive traffic patterns and analyze their impact on network performance
Configuration optimization: Test different TSN configuration parameters to find optimal settings for specific automotive applications
Failure scenario testing: Evaluate network behavior under various failure conditions to ensure safety requirements are met
End-to-end latency analysis: Measure and analyze latency for critical traffic flows across the network

Case Study: Camera-based ADAS System

A typical advanced driver assistance system might include multiple cameras sending high-bandwidth video streams to a central processing unit. Using OMNEST's TSN simulation capabilities, engineers can:

Model the network topology with cameras, processing units, and other ECUs
Configure time synchronization to ensure all cameras operate with a common time reference
Set up scheduled traffic to guarantee bandwidth for video streams
Implement frame preemption for urgent control messages
Analyze end-to-end latency to ensure it meets the requirements for real-time processing
Test the system under various load conditions to identify potential bottlenecks

Conclusion

Time-Sensitive Networking is transforming automotive in-vehicle networks by providing deterministic communication over standard Ethernet. OMNEST's simulation capabilities allow automotive engineers to design, validate, and optimize TSN networks before deployment, ensuring they meet the strict timing and reliability requirements of modern vehicles.