• by Mark Walsh  @markfwal, June 9, 2011

In its latest forecast, technology research firm IDC expects the global smartphone market to grow 55% to 472 million units shipped in 2011 as users increasingly trade feature phones for more advanced handsets. That figure will nearly double to 982 million by the end of 2015.  

Falling average prices, more phone features and lower-cost data plans will all help smartphone sales grow at four times the rate of the overall mobile phone market this year.

"The smartphone floodgates are open wide," said Kevin Restivo, an IDC senior research analyst covering mobile. "Mobile phone users around the world are turning in their 'talk-and-text' devices for smartphones as these devices allow users to perform daily tasks like shopping and banking from anywhere."

Growth rates will be steepest in emerging markets such as Asia/Pacific and Latin America, where consumers are just starting to adopt smartphones. In more mature markets, users are becoming more sophisticated about what types of experiences different phone operating systems can deliver.

"Taking this as their cue, operating system developers will strive for more intuitive and seamless experiences, but will also look to differentiate themselves along key features and characteristics," said Ramon Llamas, another IDC senior research analyst focused on the mobile device business.

In that vein, the research firm expects Android -- which eclipsed Symbian as the leading smartphone platform at the end of 2010 -- to control more than 40% of the market in the second half of 2011. Symbian, by contrast, will continue to lose share in the next five years as a result of Nokia switching to Windows Phone 7 as its primary smartphone platform.

Nokia's alliance with Microsoft will help propel Windows Phone 7 from less than 4% of the market this year to more than 20% by 2015. But that upward trajectory will not really begin until Nokia starts rolling out Windows Phone-powered devices in large volume next year.

Apple's iOS and Research in Motion's BlackBerry operating system are both expected to hold roughly steady share in the next five years, with each sustaining 18% annual growth through 2015. The BlackBerry OS will slip from about a 14% to 13% slice of the worldwide market, while iOS also drops a point from 18% to 17%.