The US outfit is expected to enhance Nokia's base station energy efficiency, which is becoming an issue as operators set up 4.9G and 5G. The financial terms of the deal were not made public.

Eta Devices is a private start-up founded in 2010. The company has its headquarters in Cambridge, Massachusetts, in the United States, and has a research and development office in Stockholm, Sweden.

The tech that Nokia wanted to get its paws on was Eta;s  ETAdvanced technology which builds on Asymmetric Multilevel Outphasing (AMO) developed at MIT by electrical engineering professors Joel Dawson and David Perreault. Dawson and Perreault, who are Eta co-founders, built an a transmitter architecture by mixing power electronics and power amplifiers. This solves a few of the problems of  efficiency and linearity in radio transmitters.

On narrowband applications, ETAdvanced claims to be  25 percent  more efficient than envelope tracking and the implementation is simpler given fewer components. Unlike envelope tracking, ETAdvanced supports ultra wideband channels of up to 160 MHz making the technology future proof by supporting both LTE Advanced and 802.11ac WiFi. Envelope tracking which only works up to 20-40 MHz - far short of the 100 MHz required by LTE Advanced and the 160 MHz utilized by 802.11ac.