Germany's T-Mobile, or Deutsche Telekom, has made the first voice call over LTE using VoLGA technology.
The Voice over LTE via Generic Access specification was developed to provide operators an alternative to CS Fallback. VoLGA supporters argue Circuit Switch Fallback is an inadequate solution to handle voice over LTE networks, despite the technology's backing from the 3GPP.
"The VoLGA test shows how operators could quickly and easily provide next-generation voice services, re-using their existing core networks," said Uwe Janssen, senior vice president of core networks at Deutsche Telekom, in a press release. "At the same time, this serves as a first step to prepare networks for the industry-agreed mid- and long-term solution for voice over LTE that will be based on IMS."
The test marks a vote of confidence on the part of Deutsche Telekom that it intends to move ahead with the controversial technology, which is not supported by the 3GPP standards body. So far, Deutsche Telekom is the only operator to openly support VoLGA.
The calls were made between a test system installed at Deutsche Telekom Headquarters in Bonn, Germany, based on a VoLGA implementation of Kineto Wireless and an independent system from Alcatel-Lucent, installed in their test center in Stuttgart, Germany. Both VoLGA-based Voice over LTE systems support inbound and outbound voice calling and SMS messaging between LTE-enabled devices and standard mobile and fixed telephones.
"Voice calling is an essential service for mobile operators. This demonstration is a key milestone towards establishing a future-proof ecosystem and shows a cost efficient way for using voice over LTE", Janssen said.
VoLGA is purported to be a long-term interim solution before carriers migrate to IMS as a permanent method of handling voice over LTE networks. The alternative interim technology, CS Fallback, routes calls over legacy networks.
In a white paper commissioned by VoLGA supporter Kineto Wireless, analyst Dean Bubley called CS Fallback "dying if not already dead."
"Charting a course on LTE, without understanding exactly when IMS telephony will arrive or how much it will cost, and without a viable alternative, is quite risky," he said. "VoLGA supports all the standard mobile telephony capabilities in Deutsche Telekom's network today, as well as all the value-added intelligent network capabilities like prepaid, local number portability, toll free calling and many more."