Japan’s NTT DoCoMo, the country’s biggest mobile phone subscriber with over 50 million subscribers, is considering fully entering the American cell phone market – as early as next year. Various Japanese media are reporting that the company plans to offer phones featuring DoCoMo’s proprietary mobile web service “i-mode” in the USA (the picture shows phones from their Japanese summer line-up).

DoCoMo is apparently planning to tap the US market first by operating as a MVNO, perhaps with AT&T or T-Mobile. Good luck with that. The background: Japan is a dramatically shrinking market for mobile phones. The eight main domestic makers of cell phones over here (Casio, Hitachi, NEC, Sharp, Toshiba, Fujitsu, Panasonic and Kyocera) sold 19 percent fewer handsets in 2008 and things look even worse in 2009.

But in the US, DoCoMo is at least 3 years too late: It’s highly unlikely the company will impress anyone with i-mode, a ten year old technology (it flopped in major markets in Europe years ago). And the MVNO concept hasn’t proven to be successful for any company in the US, has it?