Network Solutions – Communication in Time

The ongoing evolution of CANbus has led to the introduction of CAN XL, which supports data rates of up to 20 Mbit/s with current transceivers. That is enough for connecting low-bandwidth devices, but not for the data volumes described above. The main basis for data transportation though is going to be Multi-Gbit Ethernet. Infrastructure will move from supporting 2.5 Gbit/s to 5 Gbit/s, then onto 10Gbit/s operation.

With a large percentage of the data passing through in-vehicle networks being safety-critical, low latency and deterministic operation are called for. Standard Ethernet protocols do not support deterministic data flows. As a consequence, time-sensitive networking (TSN) protocols have been developed and applied here. Through these, bounded low latency communication is provided - meaning that any data which is of a safety-critical nature will be guaranteed to arrive on time. The appropriate response can then be actioned: for example, imaging data could flag there being an obstacle on the road ahead, this data would be processed by the vehicle’s on-board computer and then the brakes applied, or an avoidance manoeuvre made.

The domain-based architectures that define current in-vehicle networks will not be valid for fully autonomous driving. The domain approach to networking has everything arranged in relation to function. As the complexity of automotive systems increases and the network capacity needed has to be expanded, problems are going to emerge though. Retaining a domain-based approach would require a substantial ramp up in the vehicles’ cable harnessing. That would not only add to the overall vehicle weight (which will impact on the range that can be covered before recharging/refueling), but also result in an increase in component costs.

A zonal-based architecture offers much greater scalability. Adopting it will lead to more streamlined in-vehicle networking, with less space being needed for cabling and less financial outlay. Thanks to reductions in the weight involved, it will be possible for vehicles' range to be extended. There will be greater opportunity for integrating redundancy into systems too, in line with functional safety requirements. Also, provision will be put in place so that if one zone is out of action due to damage, another zone can cover it. The higher the level of automation within the car, the more acute the need for a zonal approach will be. It is expected that for the next few years vehicles will feature a combination of both architectures, before moving to a fully zonal-based one by the end of this decade.

In particular, 10BASE-T1S is establishing itself as the multidrop variant that connects low-bandwidth devices such as lights, switches or door modules, replacing classic CAN links in zonal architectures. A single twisted pair takes the place of multiple pairs, saving space and reducing weight, while still supporting data rates far above those of CAN over relatively long distances. It must be noted though that this requires more comprehensive electromagnetic compatibility (EMC) testing.

Wi-Fi is now being implemented into vehicle designs for in-cabin communications, with Wi-Fi 6 (802.11ax) widely adopted and Wi-Fi 6E and Wi-Fi 7 following as bandwidth demands keep growing. The same wireless lineage extends beyond the cabin: vehicle-to-everything (V2X) communication adds direct exchange between vehicles and with the surrounding infrastructure. As well as enabling device pairing, Bluetooth allows drivers to check the status of vehicles’ TPMS devices to see if tyres need inflating. The accurate positioning made possible via Ultra-wideband (UWB) will offer a more effective alternative to passive keyless entry, so that vehicles can be unlocked or even have their engines started before the driver has reached the car: something that will prove beneficial to those carrying shopping or other items.

It will mean that information relating to issues, such as road accidents, traffic jams or adverse weather conditions, can be quickly disseminated. Alternative routes can be then taken, or other preparations made. The ultra-low latency of 5G cellular communication is essential for supporting the safety-critical tasks that autonomous driving needs to undertake.

Modern cars operate like computers on wheels, requiring constant software upkeep for security, safety, and user experience. Wireless OTA updates deliver essential patches, bug fixes, and new features directly to vehicles – no dealership visit needed. While Wi-Fi is used for large updates, critical ones increasingly rely on 5G cellular networks to ensure timely delivery. This hybrid wireless approach ensures vehicles remain secure, innovative, and always up to date.

OTA allows automakers to:

• Deploy critical security fixes instantly
• Update navigation maps, infotainment, and ADAS systems
• Launch new performance enhancements without touching the hardware