Microsoft CEO Steve Ballmer has admitted that the company’s OS for mobile phones Windows Phone 7 has fallen behind competition. However, Ballmer also said that the OS would get more popular than it is now as the year progresses.

The Telegraph quoted Ballmer saying that after a year of its release, Windows Phone 7 is "very small" compared to other players in the smartphone OS world, such as Apple iOS and Google’s Android.

Ballmer said: "In a year, we’ve gone from very small to… very small."

Microsoft had launched the OS in October last year. Since then, Windows Phone 7 has around one per cent of the US handset market.

However, Ballmer said in future the market share of the OS would improve.

He said, "It’s been a heck of year and you are going to see lots of programs in that market as we move forward."

"Nokia and people in the phone business believe in us."

In February this year, Microsoft entered into a software partnership with Finnish phonemaker Nokia to provide Windows Phone 7 in future smatrphones of Nokia.

The journey for the OS has not been pleasant so far.

Microsoft had to withdraw its first update to Windows Phone 7 OS after it crashed some users’ phones.

Earlier this year, a glitch in the OS caused exchange of "phantom" data in some phones using the OS.

A study by research firm Canalys placed smartphones running Windows Phone at 3.1% of the global smartphone market in the fourth quarter, behind Google’s Android, Nokia’s Symbian and Apple’s platform.