Radio Technologies Ready for Emergencies

Public safety across Europe and other regions is getting a boost from radio technologies. For example, the 112 eCall automotive automatic-emergency-call system is set to be deployed across Europe by the end of next year. TETRA, a public-safety radio implementation that became operational in 1997, now is deployed across Europe as well as countries in Asia, Africa, and Latin America. Thus far in 2014, instrument vendors have introduced significant test solutions for the emerging 112 eCall technology as well as for the evolving and increasingly complex TETRA modulation schemes.

The eCall System

First, imagine you’re involved in an automobile accident in which you’re knocked unconscious or are otherwise unable to reach your cellphone to call for help—it could be a lifesaver if your car could make that call on your behalf. With 112 eCall, that’s what would happen. Under proposals adopted by the European Union in 2014, by October 2015, new cars will automatically be able to make such a call. The EU estimates that eCall could save up to 2,500 lives a year.¹

The eCall system automatically activates when in-vehicle sensors detect a serious crash. At that point, an automatic in-vehicle system (IVS) dials 112 (Europe’s version of  911 in the United States) and sends details of the accident to the rescue services via a public-safety answering point (PSAP). The IVS transmits a minimum set of data (MSD), including the time of the incident, the global navigation satellite system (GNSS) coordinates of the crashed vehicle, and the direction of travel (which is important for rescue workers to be able to reach disabled vehicles in tunnels). A witness to an accident also can manually trigger the eCall system by pushing a button in the witness’s undamaged car.

In an effort to be ready with test equipment for the new system, Rohde & Schwarz demonstrated its compact eCall test solution (Figure 1) for the first time in February at the Mobile World Congress in Barcelona. The setup consists of the R&S CMW500 wideband radio communications tester and the R&S SMBV100A vector signal generator equipped with an integrated GNSS simulator. This setup allows manufacturers and suppliers of automatic IVSs to perform reliable and reproducible end-to-end conformance tests on their eCall modules. The Rohde & Schwarz test solution enables users to verify whether their IVS modem can successfully initiate an emergency call, transmit the correct MSD, and establish a voice connection with a PSAP.

Rohde & Schwarz developed the R&S CMW-KA094 eCall application software to simulate a PSAP and control the R&S CMW500, thereby emulating a wireless communications network in the lab. The application also controls the GNSS simulator, supplying the coordinates required for localization of a hypothetical damaged vehicle. The test solution is fully automated thanks to the R&S CMWrun sequencer software. The user can test the RF interfaces and GNSS receiver and verify that the entire system is functioning properly.

The company describes the R&S CMW500 as a future-ready multistand-ard platform capable of testing RF interfaces such as WLAN, 2G, 3G, and LTE for tomorrow’s traffic telematics modules. The R&S SMBV100A also can be used to test navigation systems and other applications that require position information. The GNSS simulator offers a range of flexible real-time scenarios with up to 24 dynamic satellites for GPS, Glonass, Galileo, and BeiDou.

TETRA Professional Mobile Radio

TETRA is a European Telecommunications Standards Institute (ETSI) standard first published in 1995. It serves applications similar to Project 25 radio in North America, but the technologies are not compatible. TETRA was conceived in 1989 as the Mobile Digital Trunked Radio System and, in the early 1990s, was renamed Trans European Trunked Radio. In the mid 1990s, the acronym remained the same but the name changed to TErrestrial Trunked RAdio in recognition of its global market potential.²

ETSI describes TETRA as a digital trunked mobile radio standard developed to meet the needs of traditional Professional Mobile Radio user organizations involved in public safety, transportation, utilities, the military, and the oil and gas industry.

“TETRA…is used globally by many public-safety organizations, such as police, fire departments, border patrol, coast guard, and many more,” said Wolfgang Damm, president of AWT Global, in a recent press release. He added, “It is mandatory that these networks work perfectly. The issue here is not just about a nuisance with low data transfer or dropped calls. Problematic emergency networks may cause people to get hurt, and even lives are at stake. TETRA utilizes sophisticated modulation schemes, increasing data transmission rates, but unfortunately this also makes it more susceptible to interferences. Furthermore, TETRA channel-frequency configuration may cause cross-band intermodulation problems. Both issues make PIM [passive intermodulation] testing of networks paramount.”

To that end, AWT Global has launched a new PIM analyzer for TETRA and UHF frequencies: the S1L TETRA MK2 Series (Figure 2). The new PIM analyzers are designed for measuring TETRA and UHF networks in the 400-MHz frequency range. They come with a variety of test modes and capabilities, including field measurement mode, analyzer, multi-PIM display, Rx sweep, PIM vs. time, and single-carrier mode for insertion loss and coverage measurements. A distance-to-PIM option is embedded in the system; reconnecting antennas is not required.

Conclusion

As eCall rolls out at a cost of about ⇔100 per new car, concerns may be more societal than technical. The European Commission is taking care to emphasize that 112 eCall is a dormant system that transmits and receives only after a crash or after manual activation. Therefore, it cannot be used for tracking or to hijack a vehicle. Somewhat contradictorily, the EC notes that the eCall technology could be exploited for additional services, such as stolen-vehicle tracking.¹ No doubt many such issues will remain to be worked out.

As for TETRA, according to the ETSI, it will continue to evolve to meet the ever-changing user requirements utilizing the latest in technology developments. It also will face competition from LTE³ or perhaps will complement LTE. As an example of the latter, in December Cassidian delivered a prototype mobile broadband radio system that combines TETRA and LTE to enable the parallel use of all TETRA voice services and broadband data transmission, and further experimentation can be expected.

References

1. “112 eCall—Frequently Asked Questions,” MEMO/13/547, European Commission, June 13, 2013. 
2. Gray, D., “An Overview of TETRA,” European Telecommunications Standards Institute. 
3. Jackson, D., “UK seeks to replace TETRA with LTE as early as 2016,” Urgent Communications, June 6, 2013. 

For More Information

AWT Global 

Cassidian 

Rohde & Schwarz