If you're a Project Fi customer, you may have noticed improved call quality over the past few weeks. That's because Google has been quietly testing Voice over LTE (VoLTE) for a subset of Project Fi users, formally announced in a post on the Project Fi Help Forum. If you're curious to know if you're one of the fortunate testers for this new service, you can find out by looking for the signal indicator to continue displaying LTE when making or receiving a call.

VoLTE allows you to make calls over a data connection without using any of your data allocation. You also get the added benefit of faster data browsing during an ongoing call — perfect for those times when you need to look up directions on Google Maps while talking to someone. You'll also get faster call setup for a smoother overall call experience on your phone.

If you're curious to know more about Project Fi and how it works, it's Google's phone carrie, which offers you mobile data service spread across three mobile networks: Sprint, T-Mobile, and U.S. Carrier. Your phone will intelligently switch between the different networks to find the strongest connection, and it will also automatically use Wi-Fi for calls and texts wherever available.

Project Fi is restricted to Google's devices — the Google Pixel and Pixel XL, Nexus 6p, and Nexus 5X — and VoLTE support for Project Fi is also limited to T-Mobile's network, as it's currently the only partner network to fully support VoLTE.

Google hasn't set a timetable for when VoLTE will roll out to all Project Fi users, but testing will continue and we're sure we'll hear updates as things progress.

Are you one of the lucky Project Fi VoLTE testers? Let us know your experiences so far in the comments below!