Voice-over-LTE (VoLTE) technology has taken one step forward with the successful completion of what Qualcomm and Ericsson claim is the first voice call handover from a LTE mobile network to a WCDMA network using Single Radio Voice Call Continuity (SRVCC).
SRVCC is a 3GPP specified feature that enables continuity of service by switching to a WCDMA network when a consumer on a VoLTE call leaves the LTE network’s coverage area. The two companies made the call right before Christmas 2011 on an Ericsson network using a handset loaded with Qualcomm’s Snapdragon S4 MSM8960 3G/LTE multimode processor.
"As LTE networks are deployed alongside 3G networks, the ability for multimode 3G/LTE mobile devices to connect to different network technologies will be an important part of providing the best possible mobile voice and data experience to consumers," notes Cristiano Amon, senior vice president/Product Management at Qualcomm.
According to the chipmaker, SRVCC is the next logical step in the 4G LTE voice roadmap following the commercial launch of circuit-switched fallback technology (CSFB) on smartphones in 2011. CSFB allows a single radio in the handset to switch dynamically from a LTE data connection to a 3G connection when the user needs to make or receive a call. Similarly, SRVCC support enables a single radio in the handset to execute a handover of a voice call from a LTE network to a 3G network.
In addition, SRVCC and CSFB reportedly allow both LTE and 3G network connections to be supported on a single chip, eliminating the need for smartphones to use separate LTE and 3G radios and modems. “This allows OEMs to design handsets with lower power consumption and component costs, and a smaller size,” Qualcomm says. “Given that 3G networks will continue to be deployed in conjunction with LTE networks for quite some time, SRVCC and CSFB are essential to provide a seamless voice experience to customers using LTE multimode handsets once VoLTE is commercially deployed.”
Qualcomm and Ericsson will demonstrate the VoLTE test in Qualcomm’s booth at Mobile World Congress in Barcelona later this month.