INICnet technology simplifies in-vehicle audio
01 April 2019
In recent years, the automotive industry has been trying to consolidate the proliferation of networking technologies used in vehicles. Its vision is to have a so-called ‘mono-technological network’ – and the solution approach has been to adapt the Ethernet technology that has a proven track record in many other areas to automotive requirements.
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This approach solves many of the automotive networking challenges; however, it also generates others, particularly in certain infotainment, audio and acoustic use-cases. Transmission of audio signals typically demands complex and costly additional hardware and software components, increasing the risk, cost and time-to-market of the design. Carmelo De Mola, Sales & Marketing Manager for microcontroller & integrated circuit manufacturer, Microchip Technology and its subsidiary, in-vehicle network specialists, K2L, explains how a new networking technology helps address these challenges, simplifying the implementation of audio functions in vehicles.
The new INICnet (Intelligent Network Interface Controllers networking) technology offers all required audio features, such as the transfer of multiple dedicated audio and video channels, in parallel with high quality of service and low latency – without the need for additional hardware or software. It also provides an Ethernet/IP channel, enabling use-cases such as software download (including OTA or over-the-air) or diagnostics, plus a seamless link to the rest of the vehicle network, most likely automotive Ethernet.
But why do we need another open standard in the already crowded automotive standards landscape? The answer can be found by considering the major challenges facing the automotive industry. It is struggling to become more innovative as it begins to imitate fast-moving consumer product lifecycles, while at the same time trying to reduce costs. Vehicle electronics are at the heart of this. There has been a rapid rise in the amount of electronics in a typical vehicle (see Figure 1). This growth will continue due to the three megatrends of vehicle electrification, increasingly sophisticated driver assistance as we transition to autonomous driving, and growing connectivity, both within the vehicle – and with other vehicles and infrastructure.
This has led to vast amounts of data being exchanged between different components inside the vehicle, and between the vehicle and infrastructure – and this trend is only going to increase. This places new burdens on in-vehicle networks, which have traditionally been domain-based networks such as CAN, FlexRay, LIN and MOST, handling dedicated tasks for different types of data, depending on the bandwidth and real-time requirements of the communications.
As such, it is becoming increasingly common for domain-based architectures to be replaced by a backbone approach, in which an unshielded twisted pair (UTP) based high-speed Ethernet backbone covers all networking requirements.
This has the obvious advantage that Ethernet is a mature technology, with which large numbers of engineers are comfortable, and it is available with a low-cost physical layer. UTP can help reduce development costs, project risk and time-to-market for new cars. However, not all data exchanged in in-vehicle networks is natively available as packet data.
Consider, for example, audio data in infotainment systems, or in acoustic applications such as active noise cancellation (ANC) or passenger-to-passenger communications. Implementation of this kind of application using an Ethernet network implies the use of special standards, such as Audio Video Bridging (AVB), that fulfil all requirements of audio applications, including synchronisation, low latency and reliability – but are complex to implement in software and require high-performing computing power to handle the networking. The implementation cost of a complex software stack on a high performance microcontroller eats up all the benefits of a network standard.
How to avoid that and deploy a network standard for audio, acoustics and infotainment without high implementation costs? The answer to this question is INICnet technology. INICnet technology will become an open ISO standard in 2021 and supports high quality of service audio and video channels that are completely managed through INICnet ICs, or using the available lean software, so that engineers do not need extra development effort for handling the traffic on the network. INICnet technology provides UTP or coaxial cable as physical layers, and is fully compatible with Ethernet, as each node has its own MAC address, and it supports all Ethernet related mechanisms, addressing modes and packet sizes.
INICnet technology is available in two different speed grades, with a high bandwidth efficiency of more than 95%: 50 Mbps or 150 Mbps. Both options support ring or daisy chain. 50 Mbps is available over UTP, while 150 Mbps is available using coaxial cable.
INICnet technology supports phantom power and provides comprehensive diagnosis without the need for extra triggering cables. Figure 2 shows a typical example of how INICnet technology and Ethernet networks can coexist. The advantage of this architecture is that the audio video applications can be based on INICnet technology, since it handles audio or video data in native format – and developers can concentrate on their applications without caring about complex data transforming or network tasks. Another advantage is that a fast firmware update in each INICnet device could also take place over-the-air, as INICnet technology also supports native Ethernet packets – and is connected to the rest of the vehicle backbone over one of its devices, for example, 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.
Considering the ISO/OSI model for the INICnet technology’s Ethernet channel, it covers the first two layers of the model only, as can be seen in Figure 3; therefore, it can be completely abstracted from the higher layers, so that software that has been written for other technologies can be reused after a driver update. Currently there are drivers for Linux and QNX available that can be used together with INICnet ICs, allowing the INICnet technology’s Ethernet channel to be integrated into already existing IP-based system in a completely transparent way, so that development engineers do not need to care about the underlying networking technology.
Microchip offers a complete family of application-specific products targeting low-latency applications such as ANC, motor sound generation, road noise cancellation or e-call, as shown in Figure 4. Each INIC IC can be configured as a network master or slave, and can change its mode automatically if, say, after a car accident, the network is damaged, and the car user wants to perform an e-call.
The network resource management and configuration of INICnet technology can be handled using Microchip’s UNICENS unified centralised network stack. All other system management functions, such as device control, can be supported by available IP stacks such as SOME/IP stack, or any other remote procedure call (RPC) techniques. UNICENS is an open source application, available for free, and allows users to configure the whole network from a single device; this makes it possible to implement devices that do not need a microcontroller, like microphone nodes. In case there are nodes in the network that are only dealing with Ethernet traffic, like a smart antenna, these type of nodes do not need to contain any kind of network software, or best case, if the generated data is native Ethernet, it is possible to design the node without using a microcontroller in it.
The market understands the advantages of INICnet technology, as evidenced by the first automotive OEM adoption of this technology, which began in mid-2018 and will go into production in 2020. Other OEMS and Tier 1s in different regions across the globe have also already started the evaluation of the technology and are working together with Microchip experts to implement it successfully.
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