Connected cars fill frequency bands and swamp address schemes
The car of the future will be like the smartphone of its user: Always on. An increasing number of applications requires a continuous flow of data to and from cars: Navigation systems download maps and traffic information, fleet management systems transmit current position data to their home base, car-to-x systems exchange the latest information on traffic flow and road condition with roadside units and oncoming vehicles. And on top of this data streams, bored rear-seat passengers surf in the internet, prompting the infotainment system to download bandwidth-intensive video streams.
The radio technology for all of these processes is mainly based on 2G and 3G mobile radio technology. For a handful of vendors, LTE appears at the horizon - if one thinks ahead for three to five years. For specific applications, 802.11p is utilized, a member of the 802.11 protocol family optimized for communications with fast-moving stations such as cars.
At the recent CeBIT and Embedded World industry meetings, research institutes as well as commercial companies showcased their visions of "smart" traffic scenarios with telematics, car2x and infotainment content generated in the cloud being the major building blocks.
Car2x communications is one group of communications applications. Initially, the concept only included car-to-car communications (c2c) processes. The idea was that an on-board computer in the vehicles detects critical road conditions, traffic stalls and other situations relevant for oncoming drivers but beyond their field of view, and automatically exchanges such data with other vehicles. Already at an early stage of the development, the communication architects figured out that it would make a lot of sense to include so called roadside units (RSUs) which also would participate in the radio talk between the vehicles. RSUs can transmit speed limits, traffic light information or traffic congestion data to the vehicles and relay car-generated messages along the roads, increasing the range of their original transmitter. Communications between cars and RSUs is defined as car-to-infrastructure (c2i) communication.
In the car2x context, the radio connections are established by means of the IEEE 802.1p standard, a member of the 802.11 protocol family optimized for communications with fast-moving stations.
Recent research results hint that car-to-infrastructure communications will significantly outweigh purely car-to-car communication processes. At Embedded World, German research institute Fraunhofer ESK showed a prototype car-to-x communication platform which can be used for vehicle-based systems as well as for RSUs. While the standardization for is not yet concluded, the researchers have defined three groups of datagrams:
- The first group includes periodic standard datagrams that are transmitted up to ten times per second to other vehicles as well as to RSUs. These datagrams include information with regard to position, speed and driving direction. These messages help recipients to generate an overview over the general road situation and potential hazards.
- The second group embraces event-based messages such as accidents along the road. This includes recognition derived by RSUs: If many cars within the range of an RSU suddenly and simultaneously slow down their speed, the system realizes that probably there will be an accident ahead. By the same token, the RSU recognizes traffic stalls and spreads this information to drivers. Similarly, if in many cars the ESP is activated, the system determines that the road is slippery.
- The third category includes so called application messages - for instance messages related to traffic lights ahead, or traffic-related messages. RSUs can feed data from external sources such as broadcast stations or traffic control centers into the system. A common ontology enables services to describe themselves along with their requirements. Drivers as well as RSUs can request and offer specific services. The Fraunhofer project also looks into ways to balance the workload across groups of RSUs.
Despite the relatively detailed description of most message and service types, the system still is subject to standardization. "Being a member of the car 2 car communication consortium, Fraunhofer is involved in the standardization process", explained project manager Josef Jiru.
Telematics and internet connectivity
Car2x however is only one channel that connects the vehicles to the outside world. Even more in the focus of developers is the data exchange via mobile radio. Many applications such as technical status reports for the garage, the European emergency call system eCall or fleet management systems are not requiring high data rates. For this reason, they can rely on simple, cost-effective GSM communication modules. However, innovative applications are emerging, calling for connections with more bandwidth. "For the time being, GSM prevails for cost reasons. When it comes to pricing, standard GSM modules are simply unbeatable", said Hendrik Nieweg, Project Coordinator for M2M solution provider Device Insight. "UMTS and LTE are future platforms for M2M communications. However, this will take a while to materialize".
Perhaps this future will come faster than Nieweg believes. Increasingly, infotainment applications are calling for broadband access - for navigation systems downloading their maps from a remote server or for rear-seat infotainment systems accessing internet-based video streams, to mention just a few examples.
In this context, there are various options to establish a broadband wireless connection. For instance, some smart phones can be utilized as broadband modem to the outside world; inside the car, they communicate with the head unit or the infotainment system via Bluetooth. In some cases, automotive OEMs such as Audi even offer in-car WiFi nodes for the connection between the smart phone, operating as UMTS modem, and other data sources and sinks within the vehicle. An alternative to smart phone modems are automotive-based communication platforms such as Continental's AutoLinq which bring the modem functionality into the car itself.
Already, applications take shape that make use of cloud computing. "Since processing resources inside the vehicles will remain scarce, many applications could be outsourced to the cloud", explained Thilo Koslowski, automotive expert at IT market researcher Gartner. An example would the voice control component in automotive HMIs. Other examples for cloud-based automotive applications requiring a wireless broadband connection are real-time navigation data processing - the navigation system does not need a map anymore, not even for online download. Instead it constantly downloads the map image from a cloud-based server.
Against this background, telecommunication experts already raise their eyebrows. "The challenge will be the scalability of the telecommunication networks", explained Josef Lorenz, Head of Technology / West South Europe at Nokia Siemens Networks. It is not so much the amount of data that concerns the expert but the number of participants. "We are running out of IP addresses," he said. "The growing number of networked cars clearly contributes to the rising pressure to roll out IPv6."
This article appeared in EE Times Europe's April edition. To access the Digital Edition of the magazine, click here
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