Telefónica Germany will activate VoLTE on smartphones later this month once manufacturers make the enabling firmware available.
The Samsung Galaxy S5 will be the first device to be made VoLTE-ready by the network, followed by the Nokia Lumia 830, 640 and Sony Xperia Z3, before reaching subsequent models.
Telefónica launched its VoLTE service in Germany last month after working with US-based vendor Mavenir.
The operator conducted extensive testing over recent months to ensure smooth voice over LTE switching, while also divulging plans to increase the reach of its 4G network in Germany from the current 62 percent to 90 percent.
Markus Haas, COO of Telefónica Germany, said: “For us as a leading digital telecommunication provider, the implementation of Voice over LTE establishes the next important step towards providing the best network experience for our customers.
“Making calls directly via the latest mobile communication standard completes customers’ LTE experience of the O2 network.”
Voice over LTE allows users to place calls in high definition and consumes less battery than traditional circuit-switched networks as it requires less network searches from the device, Telefónica said.
It added that traditional fallback from LTE to GMS/UMTS networks would remain available for customers with smartphones that are not VoLTE-enabled.
Last week, the GSA upped its prediction for LTE deployments in 2015 following a surge in interest in LTE-A and VoLTE.
VoLTE is also helping drive the enterprise femtocell market, which ABI Research recently forecast would reach an estimated €759.9 billion by 2020.