In each of the currently operational 63 VoLTE networks, existing subscribers become de facto VoLTE users when they upgrade their devices to LTE-capable ones. Case in point: Verizon Advanced Calling (VoLTE) is device driven. Users do not sign up for Advanced Calling, but if they buy a device that supports VoLTE, then they are on the VoLTE network. For the majority of those VoLTE networks, the service is marketed as a device feature rather than something to which a user subscribes.
There is no longer any excuse to delay VoLTE, as the VoLTE ecosystem is in place. There are currently 500 commercial Long Term Evolution (LTE) networks in the world, and every single network will eventually support VoLTE, as it is inevitable that voice will go to LTE. However, making VoLTE work perfectly with no glitches remains challenging, and service providers know they need to achieve a degree of LTE network ubiquity and then beef up their IP multimedia subsystem (IMS) infrastructures to fully support VoLTE. But in the meantime, the VoLTE frontrunners are ramping up VoLTE users.
By 2020, worldwide VoLTE service revenue is projected to reach $6.3 billion, with almost half coming from North America, where average revenue per user (ARPU) is the highest in the world. At that time, Asia Pacific will have three times more VoLTE users than North America but revenue will be 13 percent lower.
Finally, as VoLTE continues to surge worldwide, the need for roaming becomes greater, giving rise to VoLTE roaming as the next big thing to come—and fueling the debate over local breakout (LBO) versus S8 home routing (S8HR).