In August 2011 Google acquired Motorola for $12.5 billion. As reported here and by others, many speculated that the acquisition would cause many handset manufacturers to consider developing their own operating systems. There has been little news on the development of alternative operating systems until today's announcement in the Yomiuri Shimbun, Japan's leading business newspaper. Yomiuri Daily reports that Docomo and Samsung are partnering to develop an operating system for cell phones. Docomo is the largest cell phone operator in Japan.
In addition to competing with Apple and Google in the smart phone market, the new OS will make it easier for carriers to offer their own services to subscribers. This feature of the OS may be attractive to cell phone carriers as they fight to avoid becoming just low value-added networks. However, an operating system built for the carriers rather than customers looks like a questionable strategy.
This article from IP Carrier describes the issues facing carriers.