Utilizing INICnet for Automotive Networking and Connectivity
In this article, learn about INICnet and how it helps to solve the question of how designers can create a safe and effective connectivity method for vehicles.
As we travel in our cars for long or short distance trips, we expect a high level of comfort, convenience, and entertainment from today’s automobile experience, as well as safety and security. As the automotive industry advances over time, significantly improving the user’s experience in the vehicle, infotainment has seen a continuous evolution.
Infotainment started with a simple car radio device and has grown to include several different networks, connecting audio, video, and other electronic devices together to form a comprehensive and information-rich travel experience.
The latest developments are pushing beyond infotainment and into audio, acoustics, voice and speech-based applications like active-noise-cancellation (ANC), in-car communication (ICC), sound zones and other applications that further enhance the comfort and safety of travel.
Today’s big question for the car industry is this: how do designers implement all this innovation while meeting quality and safety requirements, ensuring cost-efficiency and achieving quick time to market? The discussion of this question moves quickly toward the underlying networking technology supporting all features and application requirements.
At the same time, engineers also need to consider ongoing changes in the system architectures in vehicles from domain-oriented architectures to zonal architectures interconnected via high bandwidth backbones, so that the key is to choose the right networking technology when connecting all infotainments, acoustics and audio devices to the rest of the car.
Automotive Ethernet and In-vehicle Networks
The vehicle backbone architecture is typically based on automotive Ethernet. Therefore, it appears obvious to connect other applications to automotive Ethernet as well and create a so-called mono technological network that aims to convert all different existing in-vehicle networks (IVNs) to automotive Ethernet.
The approach of connecting applications is also used for legacy audio applications, as well as for new and emerging acoustics, voice and speech applications. Many companies are proposing product solutions for this approach. Even a dedicated standard called audio-video bridging (AVB) has been defined for fulfilling the special requirements of streaming audio and video data over Ethernet networks, including low latency and guaranteed bandwidth.
Pre- and Post-processing of Information
The approach that utilizes AVB over Ethernet networks comes with a disadvantage. Audio and video data needing to be pre-processed (packetized) at the source and post-processed (data extraction) at the destination, as a packet-oriented network like Ethernet is not able to transfer audio or video data in native format.
The consequence of pre- and post-processing results in complex networking software stack development and an increased cost of the network microcontrollers. Some applications, like active noise cancellation (ANC) or engine sound enhancement, are difficult and expensive to realize with this approach, because the AVB mechanisms that are necessary to fulfill the streaming requirements of these applications require powerful processors and a lot of additional software effort.
Automotive Ethernet vs. Specialized Networks
Supporters of the Ethernet approach justify their decision with the argument that Ethernet (including automotive Ethernet) is an open standard technology that reduces the number of network technologies used in vehicles, so that the network development and test complexity can be reduced, because of competition, expertise and ecosystems available in the market.
At the same time, however, many manufacturers want to avoid the additional hardware and software effort required to implement streaming applications with Ethernet and are opting for specialized networks, to cover the wide spectrum of all modern audio, speech, acoustics, and infotainment applications.
Specialized networks are often based, however, on proprietary solutions, which is considered a disadvantage by many device and car manufacturers.
INICnet Technology as a Connectivity Solution
Microchip Technology’s INICnet technology combines the capability of an application-specific network with the ability to seamlessly connect to the vehicle Ethernet backbone, offering in a single network the advantages of the other existing solutions. For carmakers, this could be used in future infotainment, acoustics, voice and speech applications.
INICnet technology conforms to the ISO21806 open standard that is currently in development and is expected to be released in early 2021. It supports a high quality of service audio and video channels with low latency audio channels (latency range 50-70 µs) that easily enables latency-sensitive applications.
These channels are completely managed through the INICnet ICs or through the available lean software, so that the engineers do not need extra development effort to handle the traffic on the network.
INICnet technology uses unshielded twisted pair (UTP) or coaxial cable as its physical layers. Since each node has its own media access control (MAC) address, it is fully compatible with Ethernet and supports all Ethernet-related mechanisms, addressing modes and packet sizes.
The built-in Ethernet channel in INICnet technology allows transmission of native Ethernet packets at the same time as distributing audio, video, voice, and speech data over a single medium (e.g., a simple UTP cable). This Ethernet-based data channel enables features such as SW download or diagnostics over Ethernet by using protocols like TCP, UDP or DoIP.
Standard Ethernet-based software is available in the market and can be re-used with INICnet technology; this reduces risk, time, and implementation costs. INICnet technology supports power over data line (PoDL) and provides comprehensive diagnostics without the need for extra triggering cables.
Figure 1 shows a typical example of how INICnet technology and an Ethernet network can coexist, as they both speak the same language: Ethernet.
Figure 1. Seamless connectivity between INICnet and Ethernet vehicle backbone without using a gateway.
The advantages of the network architecture shown in Figure 1 include:
- Audio, video, voice, and acoustics applications can be based on INICnet technology as it handles audio or video data in native format;
- Developers can concentrate on their applications without caring about complex data transformation or network tasks;
- Fast firmware update in each INICnet device could also take place over the air, e.g., to fix a security issue or improve the functionality. INICnet technology supports native Ethernet packets and is connected to the rest of the vehicle backbone over one of its devices such as the head unit;
- There is no need to have a gateway application in the head unit as each INICnet device can be directly addressed by its own unique MAC address.
The ISO/OSI Model for INICnet Technology
INICnet technology is available in two different speed grades with a high bandwidth efficiency of more than 95 percent: 50Mbit/s or 150MBit/s. Both options support ring and daisy chain topologies. Fifty Mbit/s are available over UTP while 150Mbit/s are available over coaxial cable.
Considering the ISO/OSI model for INICnet technology’s Ethernet channel, it only covers the first two layers of the model, as can be seen in Figure 2. It can be completely abstracted from the higher layers so that software written for other technologies can be reused after a driver update.
Figure 2. INICnet technology in the ISO/OSI model.
Currently, there are drivers for Linux, Android, and QNX that can be used together with the INICnet ICs and allow the INICnet technology’s Ethernet channel to be integrated into an already existing IP-based system in a completely transparent way. This way, the development engineers do not need to focus on the underlying networking technology.
Microchip Technology offers a complete family of application-specific products targeting low-latency applications such as ANC, motor sound generation, road noise cancellation, e-call, and other applications that require low latency, as shown in Figure 3.
Figure 3. The complete family of application-specific INIC ICs.
Each INIC IC can be configured as a network master or network slave and can change its mode automatically. For example, in the case of a car accident, if the network is damaged, the car user can still perform an e-call.
Network Configuration and Management with UNICENS
The network resource management and the network configuration of INICnet technology can be achieved with Microchip’s UNICENS unified centralized network stack. All other system management functions such as device control can be supported by available IP stacks such as a SOME/IP stack, or any other remote procedure call (RPC) techniques.
UNICENS, an open-source application, is available for free and lets users configure the whole network from a single device. This makes it is possible to implement devices that do not need a microcontroller, like microphone nodes. Nodes in the network that only deal with Ethernet traffic, like a smart antenna, do not need to contain any kind of network software. In the best case, if the generated data is native Ethernet, it is possible to design the node without using a microcontroller in it.
Advantages of INICnet technology can be seen in the first automotive OEM adoption of this technology in mid-2018 with production set to begin in 2021. Carmakers and Tier 1s in different regions have already started the evaluation of the technology and are working together with Microchip to drive it forward.
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