The automotive industry is currently undergoing a major transformation, driven by significant megatrends such as electrification, connectivity, autonomous driving, and shared mobility. Car manufacturers are challenged to quickly adapt their electrical/electronic (E/E) architectures to support these trends and provide innovative solutions. This presents both technical challenges and opportunities for automotive OEMs to transform their E/E architectures and leverage new revenue streams.
The transition toward zonal-based architecture
To meet these challenges and opportunities, the industry is transitioning towards zonal-based architecture. Unlike domain-based architectures, which have become cumbersome due to continuous add-ons, zonal-based architectures determine connectivity based on physical location rather than function. This shift significantly reduces the number of electronic control units (ECUs) in vehicles and significantly reduces the size of harness cabling. Furthermore, zonal architectures decouple hardware and software, enabling a true service-oriented architecture (SOA) approach or the software-defined vehicle (SDV).
Ethernet has emerged as a critical technology in the automotive industry, providing the scalability, robust transmission media, service-based architecture, and advanced safety and security building blocks necessary for widespread adoption.
Advantages of 10BASE-T1S
10BASE-T1S, developed as part of the IEEE 802.3cg-2019 standard, provides the missing link for an Ethernet-only in-vehicle network. It enables Ethernet-to-the-edge connectivity and addresses the needs of zonal-based architecture. One of the unique aspects of 10BASE-T1S is its support for a multidrop technology. This bus implementation, where all nodes are connected over the same unshielded twisted pair cable, reduces cost by requiring only a single Ethernet PHY in each node. It eliminates the need for switches or gateways towards legacy network technologies.
The standard specifies support for at least eight nodes (with the potential for more) and allows bus lengths of up to 25 meters. Power over data lines (PoDL) in a 10BASE-T1S network is also possible, further reducing cable complexity and weight, and improving reliability.
To ensure efficient network access, 10BASE-T1S utilizes Physical Layer Collision Avoidance (PLCA) instead of the traditional CSMA/CD procedure. PLCA implements a time-controlled mechanism where a designated "coordinator node" transmits a beacon to signal the start of a transmission cycle. Each node is assigned a fixed transmission slot, preventing access collisions on the bus and ensuring deterministic maximum latency. This approach enables optimized utilization of the available 10 Mbps bandwidth.
10BASE-T1S integrates easily into Ethernet-based networks and leverages the same communication stack as faster Ethernet variants. This allows for uniform and consistent communication throughout the network, from central control units to sensors and actuators. The use of a service-oriented communication approach, such as SOME/IP, becomes straightforward.
Paving the way for intelligent, autonomous, and software-defined vehicles
10BASE-T1S Ethernet brings a range of advantages that make it highly suitable for a broad and varied range of automotive applications, encompassing sensors and actuators across multiple domains.
These five reasons describe why 10BASE-T1S is boosting software-defined vehicles:
It enhances zonal architectures.
It has a large capacity to reduce weight.
It supports power over data lines.
It provides deterministic network performance for a bus technology
Its seamless integration contributes to the advancement of automotive E/E architectures.
As the automotive industry continues to evolve, 10BASE-T1S plays a significant role in enabling connectivity, enhancing efficiency, and paving the way for intelligent, autonomous and software-defined vehicles.
Learn how to boost your 10BASE-T1 adoption with the Spirent