'Connectivity is also going to be vital between the car and its environment. Consumers will need reliable internet connectivity to access their preferred online services, as well as to support access to concierge services such as GM’s OnStar network.'
Technology review
And then there is V2X, a whole new layer of emerging connectivity;
• between vehicles and pedestrians (V2P) to alert drivers
• between vehicles and other vehicles (V2V) to exchange information about their speed and location to avoid collisions
• between vehicles and infrastructure (V2I) to exchange information with traffic-management and other forms of infrastructure, to ensure safety at busy intersections and in places with poor visibility.
North America and Europe already have plans to implement V2X communications strategies, using the IEEE 802.11p variant of the familiar WiFi standard starting in 2019. Companies such as Murata are taking advantage of this opportunity by developing V2X wireless communication modules, software and support that use the standard.
Updating wired automotive interfaces
Vehicles have been managing a lot of decentralised sensors, actuators and control units for decades now, and there has been a steady evolution in the enabling bus infrastructures.
One of the best-known is LINbus (for Local Interconnected Network), which has a data rate of 20Kbit/s, can be implemented on a single wire with a single master, and is used to create small subnets of sensors and actuators in vehicle networks.
CANbus, otherwise known as the Controller Area Network or ISO 1189,
was introduced to enable large numbers of engine control units to be networked. The standard supports data rates of up to 1Mbit/s, is implemented on two wires with support for multiple masters and is deemed suitable for ‘soft real-time’ applications, where timing is important but not safety-critical.
FlexRay was introduced to support hard real-time (in other words, safety-critical) applications, at data rates of 10Mbit/s. It supports multiple masters, can be implemented on two wires or optical fibre, enables deterministic responses and is designed to be redundant.
MOST, the Media Oriented System Transport, was introduced to make it easier to integrate infotainment services into cars. It supports data rates of up to 24Mbit/s, multiple masters, and is optimised for streaming multimedia data.
The ubiquitous Ethernet is now also making an appearance in vehicle bus architectures, to support much higher data rates and the levels of management and control that are necessary to handle the flow of large amounts of safety- critical data. Interestingly, current work on improving the determinism of the bus architecture builds on work to improve its ability to handle streaming media. The Audio Video Bridging extensions to the standard are now being used as a basis for work on time-sensitive networking, which will add facilities to ensure that time- critical data can pre-empt other data flows on the bus to ensure it arrives within the specified latency.
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