T-Mobile is said to be considering building a multi-billion dollar fiber network to provide home internet service. The main home-focused offering is connected with 5G instead of other wired infrastructure.

A $4 billion joint venture or commercial partnership is being worked on by the carrier and Citigroup. It feels like early days for the plan, but it still feels like a significant step for the wireless carrier, which has traditionally used and managed a very different kind of infrastructure.

The same can not be said for its competitors, who have been offering Fios fiber internet in several states for a long time.

T-Mobile's current home and business internet offerings are dependent on its 5G andLTE networks. While that allows it to roll out coverage more easily than if it had to lay fiber in the ground, there are limitations, poor service can lead to a bad user experience, and a fiber network will almost certainly beat a cellular one. For T-Mobile, it would be great to be able to offer both options in some areas, for example, a relatively inexpensive cellular option for people with relatively light internet needs and a fiber option for power users and people who need rock-solid service.

T-Mobile didn't respond to the request for comment on its search for partners to build a fiber network and how many users are currently on its fiber home internet pilot When we wrote about it in August of last year, T-Mobile had only made it available in parts of New York City and was using a local fiber provider. The carrier is looking into other partnerships where it could make similar arrangements.

It's likely that T-Mobile's main home internet offering will be its fixed-wireless service. It can be difficult to build out a fiber network in just a few dozen areas, one that can be expensive and time consuming. T-Mobile announced earlier this year that a million people had signed up for its 5G home internet service and that it was able to provide it to over 40 million households.