Fujitsu is a major player in the Japanese mobile market. But they have little presence outside their home market.
The company has indicated that they eventually want to expand mobile operations to international markets in the future. And USA is one of the priority destinations.
They have a close relationship with NTT DoCoMo in Japan. They would need similar deals in other markets to ensure that they sell enough units in those markets.
Fujitsu is already manufacturing Android and Windows Phone based devices in Japan. They have the necessary expertise to launch exciting models in USA. US market is crowded and very competitive. Nokia might be the world’s largest mobile phone maker but they have never done well in USA. Fujitsu is not going to find it easy as well.
The US smartphone market is dominated by players like Apple, Samsung and LG. Motorola, Sony and HTC are other players.