Help is on the way

Help is on the way

20-Jun-2019

How the automotive emergency call service eCall works

The emergency call button (usually red) on the dashboard is required for all vehicles sold in the EU after March 31, 2018, although some models had it even earlier. It triggers a call to the standard European emergency number 112. This could be provoked due to an acute health issue of one of the occupants that requires immediate attention, or due to a serious accident involving another vehicle and witnessed by a third person.

However, an even more important function of the eCall system is to make an emergency call when an airbag has been triggered, which usually only happens when there is a massive impact. Thanks to eCall, no matter where you are in the EU, you can rest assured that the emergency call center will receive all essential information that the emergency response service needs: the location of the accident (geographic coordinates), the direction of travel (important on highways), the time of the accident, the type of vehicle, how the car is powered or the fuel type (important for the fire department), and the number of occupants (based on the number of fastened seat belts or other seat occupancy detection method).

Additional information is optional. A voice connection must be established to enable data transmission. Using this connection, the operator can converse with the occupants if they are able to talk. Other insights can also be gained from the audio console.

No more road casualties by 2050
No more road casualties by 2050
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No more road casualties by 2050

eCall was launched after many years of discussion and coordination at the European level. The EU had adopted local initiatives, such as Sweden’s Vision Zero project whose goal was to use administrative and technical means to reduce the number of fatal or serious injuries involving road traffic to zero.

However, the EU soon had to tone down their initially very ambitious goals. According to current planning, the original target of halving the number of road deaths from 2010 to 2020 is to be achieved by 2030. By 2050, there should be virtually no more road casualties in Europe.

Manufacturers take the lead
Manufacturers take the lead
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Manufacturers take the lead

A prerequisite for an automotive emergency call system is that vehicles always know their location and can transmit them wirelessly. The technologies required for this – satellite positioning systems and digital telecommunications – were introduced practically simultaneously in the USA in the mid-1990s and were quickly used to set up proprietary automotive emergency call services. General Motors and Ford were the pioneers – GM with its OnStar system, which first appeared in the 1996 Lincoln Continental, and Ford with RESCU, which required the press of a button to determine the location instead of working automatically. The first European manufacturers followed a short time later, for instance BMW in 1997.

This meant that for a long time emergency call services were neither standardized nor managed by public authorities. Instead, they were left to the initiative of the manufacturers, who naturally didn’t have any political goals and viewed their services as a competitive advantage and wanted to make money with them. The emergency call centers were therefore not public services. They were private and commercial. By contrast, the European eCall system is a legally based system and all 28 member states of the EU are obliged to introduce it. To enable it to work everywhere in Europe, a solution was chosen that was leading edge at the time it was specified, but must be regarded as unfortunate from today’s perspective.

Outdated from the start
Outdated from the start
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Outdated from the start

Back when the foundations of eCall were laid, the only system that could be regarded as broadly available was the venerable GSM mobile communications system, which is now called a 2G system. Although GSM is digital, which means it transmits bits, it is essentially a pure voice system. Extensions to the standard, such as GPRS and SMS, allowed rudimentary data communications, but to be on the safe side there was reluctance to require their availability. To enable data transmission despite this, a trick was employed: the bits were converted to tones and sent over the voice channel.

Fax machines also work this way, and if you have ever called a fax number by mistake, you know what these tones sound like. This method is not very fast by current standards, but it is fast enough for eCall. Only 140 bytes have to be sent to the emergency call center, which is hardly more than the content of a text line. This minimum set of data (MSD) contains the previously described information. In this respect, there was nothing wrong with the system since it fulfilled its purpose. But there is another reason why vehicles equipped with this solution are probably older than the eCall system: GSM networks are on the verge of extinction. Their frequencies are urgently needed for more advanced methods such as LTE and 5G. Now that LTE can also transmit voice (unlike GSM, it is a pure wireless data system that had to be retrofitted with voice), there is no longer any need for a pure voice system such as GSM, especially since LTE coverage will be available throughout Europe in a few years. If the EU wants to have a functioning public automotive emergency call system, they need to come up with new resolutions quickly. That will not be difficult in technical terms, since the successor is already specified.

By the way, this time Russia is well ahead of the European Union. Its emergency call system ERA-GLONASS has not only been mandatory for Russia and the countries of the Eurasian Customs Union (EACU) since early 2015, it also includes buses and trucks (versus only passenger cars in the EU) and also functions in UMTS (3G) networks. It uses the Russian GLONASS satellite system for localization, but can also work with GPS. Aside from that, ERA-GLONASS works the same way as eCall and transmits the same information.

The successor is ready
The successor is ready
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Open Lightbox

The successor is ready

Next Generation eCall (NGeCall) uses one of the LTE mobile communications standard’s software module. LTE’s IP multimedia subsystem (IMS) allows a modern implementation of the basic eCall functionality and offers a lot of scope for extensions. Tone signals are a thing of the past in the LTE based version. However, the modern system does set up a voice connection (voice over LTE, VoLTE) ‒ an essential component of every emergency call system.

NGeCall transmits the same data as eCall: the 140-byte minimum data set. However, since the system establishes a fast data connection, it also offers the option of transmitting additional data that could be helpful in an emergency situation. For example, smart watches linked to the vehicle's telematics system could deliver the health data of the occupants. Or an online camera could provide a view of the situation on site. In the other direction, it is conceivable that the emergency call center could send remote control commands to the vehicle, for example to unlock the doors or turn off the ignition. The latter was already possible in 2009 with the GM OnStar system, but it was only intended to disable stolen vehicles.

Although NGeCall has been technically defined, it has not yet been officially adopted, so its future is still uncertain. Since most of its technical prerequisites already exist, it can be assumed that vehicle manufacturers will take the initiative just as they did in the early days of emergency call systems. Many telematics systems support not only eCall, but also a brand-specific system, whose design is solely up to the manufacturer. The manufacturer only has to ensure that the eCall standard becomes active automatically if their own system is not available, or that vehicle owners are free to choose which system they want to use.

Tested safety: testing eCall, NGeCall and company
Tested safety: testing eCall, NGeCall and company
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Tested safety: testing eCall, NGeCall and company

Like all complex communications and data processing systems, faultless operation of an automotive emergency call system must be verified in tests. The vehicle's telematics units must be able to generate and process the signals exactly as defined by the relevant standards. Rohde & Schwarz has developed a universal test solution that is equally suitable for eCall, NGeCall and ERA-GLONASS. The test system simulates a real environment consisting of a mobile network and a satellite positioning system. It runs through an emergency scenario and measures the behavior of the DUT – a telematics unit (in-vehicle system or IVS).

The test system consists of an R&S CMW500 mobile radio communication tester that simulates the mobile network (GSM, LTE or any other network), an R&S SMBV100 signal generator that produces the satellite signals (GPS, Galileo or GLONASS), and a PC that assumes the role of the emergency call center (public safety answering point, PSAP) and controls the test sequence. All practically relevant scenarios can be simulated with this test setup, such as the case where the vehicle leaves the coverage area of an NGeCall network (the mobile network indicates to the receiver whether it supports this kind of system). In this scenario, the IVS must independently access the eCall standard in the event of an emergency.

Many customers – manufacturers as well as test institutes – are already testing their emergency call electronics with the Rohde & Schwarz system. Its flexibility is especially impressive, and its ability to simulate every current mobile network and every satellite positioning system makes adjustments easy. No matter how the EU or any other part of the world designs their future automotive emergency call system, the Rohde & Schwarz solution will be able to test it.*)

*) A solution for 5G would require an extension of the mobile network tester.

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