T-Mobile International has confirmed that it is assisting in the development of the Voice Over LTE via Generic Access standard by becoming a member of the bespoke forum which is developing the nascent protocol for possible ratification by the 3GPP as the standard voice protocol for LTE networks and handsets.
Since LTE is a flat all-IP-based standard with no legacy support for SMS control channels or circuit switched voice calling, carriers are struggling to decide how to address the problem, but VoLGA is said to benefit from support from all of the major network hardware vendors save for Nokia-Siemens Networks who are developing their own LTE voice protocol.
Another issue left to address is the myriad of stopgaps, which carriers are already struggling with, if LTE is ratified without an integrated voice protocol.
IP Multimedia Subsystem which is approved by the 3GPP is considered immature for use with LTE.
Circuit-Switch fallback where second or third generation networks are used for LTE voice services, making devices more expensive due to the additional hardware needed.
Circuit-Switch-Over-Packet where voice or SMS traffic is tunneled over LTE service, which would also require maintenance of older less efficient network equipment.
For its part, the VoLGA Forum hopes to have the third stage of the specifications completed before the end of the year so that the standard can be submitted to the 3GPP for a work item in Release 10 of the standard body’s specifications, which hinges on enough carrier and network equipment manufacturer support beforehand in order to make the formal submission.