Nokia said it would plan, manage, deploy and integrate mobile network technology and software for Rakuten.

Rakuten has more than 100 million users in Japan, something it can build upon when it enters the market as a mobile operator and digital services provider.

"The building of the network is underway and user trials in Tokyo have already begun," Nokia said.

Japan currently has three dominant mobile services providers - NTT DoCoMo Inc, KDDI Corp and SoftBank Group Corp.

(Reporting by Tarmo Virki; Editing by Kirsten Donovan)