T-Mobile US followed rivals Verizon and AT&T by revealing plans to hold field trials for 5G later this year, with vendors Ericsson and Nokia announcing separate partnerships with the operator.

The news does however come as somewhat of a surprise in light of comments made by T-Mobile US’ outspoken CEO John Legere just last week, who hit out at Verizon for claiming it would launch 5G in the next few years.

In a brief statement released by Nokia, Neville Ray, CTO at T-Mobile US, said the company would build on investments made in its 4G network, which “puts us on the path to real 5G use cases once 5G consumer smartphones are available in the 2020+ timeframe”.

Nokia said it is developing pre-standards 5G testing for lab field trials in the second half of 2016, and the companies will use pre-selected spectrum in the 28GHz band to trial and test 5G components, accompanying “use cases that support massive bandwidth capacity and virtual zero latency”.

In its own announcement, Ericsson said the partnership with T-Mobile US builds on existing collaboration in LTE-A and network transformation, with the companies looking to “drive 5G development and standardisation, and to explore new business opportunities”.

Ericsson added it has now signed more than 20 memorandums of understanding to test 5G with operators across the world.

It is unclear whether T-Mobile US is working with any other vendors for 5G development at this stage, with the company yet to release its own official statement.