Google's Project Fi MVNO announced Wednesday that U.S. Cellular (NYSE: USM) will be joining its Partner Network, allowing the service to shift users onto U.S. Cellular connections along with its other options.

"With the addition of a third network, Project Fi now gives you more coverage and speed, helping you stay connected wherever you are," Evan Jacobs, product manager for Project Fi, wrote in a blog post announcing the addition.

Project Fi previously had access to Sprint (NYSE: S) and T-Mobile's (NYSE:TMUS) networks, dynamically switching between the two when Wi-Fi, the service's default, isn't available. The addition of U.S. Cellular will give the partner network more options, increasing the likelihood of finding a faster connection.

Jacobs explained that multiple cellular networks are usually available in a user's location, but because of factors like the placement of nearby buildings and cell towers, some may be faster in certain locations than others.

The Project Fi Partner Network works by evaluating the patchwork of connections available in a given spot and connecting to the one that will offer the fastest speed at a given time. Jacobs asserted that this gives Project Fi more reliable access and speeds than a singular network alone.

"By accessing multiple cellular networks, Fi users have a connection nearly 99 percent of the time, and spend about 95 percent of cellular time on LTE – which will improve even further with the addition of U.S. Cellular," he wrote.

U.S. Cellular, the fifth-largest wireless carrier in the country, recently came off a sub-par financial quarter, and is actively exploring ways to drive more business. Given the timing, it's conceivable that this partnership is such a method, though we don't know for how long the partnership has been in the works.

Google Fi recently became available to all users as the company ditched the invitation-only policy it launched with 10 months ago. New users can now sign up for the service.

For more:

- read the blog post on the U.S. Cellular partnership

- learn more about Project Fi's offering

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