Rohde & Schwarzhas reached a milestone in the introduction of voice over LTE telephony for the IP multimedia subsystem (IMS). The T&M specialist has verified the world's first test cases for IMS emergency calls over EPS/EUTRA in compliance with GCF Work Item 154.

All mobile phones and smartphones must be able to place emergency calls, both in their home network and in other networks – even without a SIM card – with the correct signalling of an emergency call being crucial in an emergency.

In cooperation with leading chipset makers, Rohde & Schwarz claims to be the first T&M manufacturer to verify test cases defined in GCF Work Item 154 for IMS Emergency Call over EPS/EUTRA. The R&S CMW500 multi-RAT protocol tester was used to test the RRC connection setup for an emergency call and the IMS emergency call registration. This is a key step in the transition toward pure LTE networks. In the past, placing emergency voice calls on LTE networks was especially challenging for network operators, chipset makers and consumer electronics manufacturers.

These verified test cases underscore the company’s pioneering role in the field of IMS conformance testing. Rohde & Schwarz has validated test cases for call control, SMS over IMS as well as multimedia telephony services over IMS. It works with and assists leading network operators in covering their test specifications. Chipset makers, consumer electronics manufacturers and network operators use the R&S CMW500 multi-RAT protocol tester, for example, in a diverse range of applications for IMS protocol tests.

In addition to the emergency call requirements in the GCF Work Items and the PTCRB Request for Test, which are based on the 3GPP specifications, country-specific guidelines also have to be met. In the US, for example, the Federal Communications Commission (FCC) requires that the caller’s position be transmitted when making 911 calls. The R&S TS-LBS test system from Rohde & Schwarz provides the right solutions for this requirement: appropriate protocol tests for transmitting the caller’s position, minimum performance tests for A-GNSS as well as network-based positioning methods such as OTDOA and eCID.

The R&S CMW-KC504 IMS emergency call over EPS/EUTRA software option for the R&S CMW500 multi-RAT protocol tester is available this month [September 2013].