The number of smartphones shipped worldwide will reach one billion this year as the device becomes more affordable, driving adoption in emerging markets and the prepay segment in mature markets, according to a new report from Gartner.

Last year, 675 million smartphone units were shipped. These numbers point to how quickly smartphones have been embraced by consumers, with the first mass market smartphone having been introduced just six years ago in 2007 by Apple.

"The trend towards smartphones and tablets will have much wider implications than hardware displacement," said Carolina Milanesi, research vice president at Gartner, Stamford, CT.

"Software and chipset architecture are also impacted by this shift as consumers embrace apps and personal cloud,? she said.

Tablet sales jump
In total, Gartner expects 1.875 billion mobile phones, including smartphones and features phones, to be shipped this year.

In 2014, there will be 1.949 billion mobile phones shipped worldwide and by 2017, 2.128 billion.

Tablet sales are also growing as lower-priced tablets and their growing capabilities accelerate the transition from PCs to tablets.

In 2013, 197 million tablets are expected to be shipped worldwide, up 69.8 percent from 116 million last year. By 2014, the number will reach 266 million and by 2017, 468 million.

As smartphones and tablet sales grow, the traditional PC market is forecast to decline 7.6 percent. Ultramobiles will help offset this trend so that combined sales of traditional PCs and ultramobiles will show a 3.5 percent decline in 2013.

Android is leading OS
The shift away from PC and toward mobile becomes more evident in operating system shares by device shipments.

Android continues to be the dominant OS in the device market thanks to strong sales of Android smartphones. Competition for the second spot will be between Apple?s iOS/Mac OS and Microsoft Windows.

Gartner expects 861 million Android devices to be shipped in 2013, up from 497 million last year.

In comparison, 354 million Windows devices will be shipped this year - up from 346 million last year - while 293 million iOS/MacOS devices will be shipped - up from 213 million last year. Gartner expects 31 million RIM devices to be shipped this year, down from 35 million last year and 871 million other devices will be shipped this year, down from 1.1 billion last year.

Going forward, Android will continue to lead. Gartner forecasts 1.069 billion Android devices to ship next year and 1.468 billion in 2017. There will be 397 million Windows devices shipped in 2014 and 571 million in 2017.

IOS/MacOS will sell 359 million devices next year and 504 million in 2017. RIM and all others will continue to see their share decline.

Overall, worldwide PC, tablet and mobile phone combined shipments are expected to reach 2.4 billion units in 2013, a 9 percent increase from 2012. By 2017 overall shipments are expected to reach 2.9 billion units.

"While there will be some individuals who retain both a personal PC and a tablet, especially those who use either or both for work and play, most will be satisfied with the experience they get from a tablet as their main computing device," Ms. Milanesi said. ?As consumers shift their time away from their PC to tablets and smartphones, they will no longer see their PC as a device that they need to replace on a regular basis."

Final Take
Chantal Tode is associate editor on Mobile Marketer, New York