I. Vehicle Ethernet
Traditional Ethernet protocols, employing carrier sense multiple access (CSM) and collision detection technology, fail to meet the real-time requirements of automotive networks in terms of packet latency, sequencing, and reliability. Therefore, common in-vehicle local area networks (LANs) still rely on CAN-based real-time fieldbus protocols. However, with the explosive growth of automotive electronics technology, the number of ECUs (Electronic Control Units) is constantly increasing, and audio-visual entertainment signals are being incorporated into in-vehicle communication. This has rendered the traditional in-vehicle bus, with its high real-time performance and low bandwidth, unsuitable for the evolving trends in automotive electronics.
After long-term research, the Institute of Electrical and Electronics Engineers (IEEE) approved the first automotive Ethernet standard, "100BASE-T1", in 2016. Based on Broadcom's BroadR.Reach solution, it uses a single pair of unshielded twisted-pair cables at the physical layer and employs a more optimized scrambling algorithm to reduce signal correlation and increase real-time performance, providing 100Mbps of high real-time bandwidth in vehicles.
The communication quality of high-speed Ethernet in automotive interference environments is a key issue that needs to be examined. Especially for 100BASE-T1 networks, which use unshielded cables, they are more susceptible to current surges and electromagnetic interference, leading to performance instability or even malfunction. Currently, there are conformance testing methods based on the Ethernet physical layer to test the return loss, timing jitter, and maximum output drop of signal transmitting equipment; the RFC2544 standard provides testing methods for key performance indicators such as Ethernet latency, throughput, and packet loss rate. However, these common methods are based on traditional Ethernet, do not support 100BASE-T1 automotive Ethernet, and do not consider the interference characteristics of the automotive environment.
II. Advantages of In-Vehicle Ethernet
Since Ethernet has been the standard technology for local area networks (LANs) for decades, it has played a vital role in the development of various communication methods. Over time, numerous transmission methods and protocols have been developed, implemented, and validated to provide rich functionality running on Ethernet networks.
TCP/IP is a suite of protocols that enables Internet connectivity and applications. It has been used on Ethernet from the beginning, providing fundamental functionalities such as email, World Wide Web access, file transfer, and instant messaging. Audio-Video Bridging (AVB) is another communication standard designed to run on Ethernet, transforming the network into a real-time system suitable for high-quality infotainment systems of audio and video streaming. In addition to TCP/IP, AVB, and other communication suites that provide support for thousands of applications on Ethernet, many other protocols implement supporting functions such as address resolution, network tracing, and clock synchronization. All of these are defined in standards defined by organizations such as IEEE and the Internet Engineering Task Force (IETF).
All these protocols, suites, applications, and utilities are designed to run on any type of Ethernet, regardless of its underlying implementation. Therefore, applying Ethernet to automobiles immediately means these capabilities can also be applied to automobiles. In turn, this gives automotive application developers access to a vast array of industry standards, extensive implementations, and thoroughly "field-tested" features and capabilities.
Furthermore, Ethernet not only provides automotive companies with countless protocol and application options, but also grants them access to a larger pool of human capital, enabling synergies between traditional technology and automotive technology companies that were previously impossible. Communication between electronic control units (ECUs) in vehicles will no longer be based on industry-specific technologies; they will use the same technologies found in virtually every other industry. This, in turn, will make inter-industry collaboration easier, opening up possibilities for advanced features and uses that have so far been speculative, while others remain to be envisioned. We will soon have cars with advanced audio and video streaming capabilities, traditionally found only in home or professional systems; cars talking to toll booths; smart charging systems; and further developments in the field of autonomous vehicles. This trend of consolidation between the automotive and non-automotive industries is being spearheaded by companies like Broadcom. Broadcom, a California-based semiconductor company that has traditionally derived most of its revenue from outside the automotive industry, is now becoming a significant player in that market.
