T-Mobile on Monday announced a multi-year agreement with Nokia to implement the Finnish company’s 5G equipment in the carrier’s U.S. network.

The $3.5 billion deal is Nokia’s largest 5G partnership worldwide, company officials said.

“This is a testament to our companies’ strong and productive working relationship, one which has produced several important technological milestones in recent months, and which now allows us to make 5G a commercial reality,” Nokia Chief Customer Operations Officer Ashish Chowdhary said in a statement.

Nokia said it would supply 5G technology, software and services — including AirScale radio platforms and cloud-native core, AirFrame hardware and CloudBand software — for T-Mobile’s 600 MHz and 28 GHz spectrum holdings.

T-Mobile earlier this year announced plans to being building networks that can be upgraded to 5G in 30 U.S. cities by the end of 2018.

“Every dollar we spend is a 5G dollar, and our agreement with Nokia underscores the kind of investment we’re making to bring customers a mobile, nationwide 5G network,” said T-Mobile CTO Neville Ray.