3 Sweden enabling voice for LTE handsets with CSFB, supported by Mavenir Systems

Hi3G Access Sweden, offering mobile services under the ‘3’ brand, has selected Mavenir Systems to support voice services for its 4G Long Term Evolution (LTE) network subscribers, using Circuit Switch Fallback (CSFB). CSFB allows voice calls to be delivered to/from LTE handsets via the operator’s 3G network, and acts as an interim technology solution ahead of the introduction of voice-over-LTE (VoLTE) – which delivers voice in IP packets alongside data, and is beginning to be implemented on a handful of networks worldwide. Mavenir stated that its VoLTE IWF (InterWorking Function) will enable Hi3G to introduce CSFB quickly and with minimal impact on its networks. TeleGeography’s GlobalComms Database says that the first LTE handsets in Sweden went on sale in February 2012, when both Tele2 and Telia launched 4G smartphones with voice support using CSFB, which will remain in use in the longer-term as a roaming solution outside of 4G coverage areas, augmenting VoLTE services.