Sprint confirmed it remains on track to launch VoLTE service later this year, a move which will bring it in line with major rivals in the US.

A representative told Mobile World Live Sprint had been testing VoLTE for more than a year and compatible devices (including Samsung’s flagship Galaxy line) are already being sold to customers. A software upgrade will enable VoLTE on those devices when network rollouts begin in a number of markets, the representative added.

VoLTE will initially be available to post paid subscribers, with prepaid to follow at a later date, the representative said. Once the technology is live, customers with compatible devices will be able to use VoLTE for their voice service rather than Sprint’s existing HD Voice offering, which provides clearer calls but doesn’t require LTE service.

The operator is years behind its domestic competitors, as AT&T, T-Mobile US and Verizon all began VoLTE rollouts in 2014. It’s clear why operators were quick to jump on board: VoLTE offers better call quality for customers as well as up to three-times more capacity than 3G voice and data.

Sprint held off to allow interoperability kinks to be worked out and give it time to get the experience right. The representative said Sprint’s goal with VoLTE is to match the “high-quality experience” its customers get with its HD Voice product today.