Microsoft Corp is set to announce new mobile phone software on Monday, according to sources close to the company, as it looks to wrestle back market share from Apple Inc's iPhone and Research in Motion Ltd's BlackBerry.

The world's largest software company, which makes operating systems for phones made by HTC Corp, Samsung Electronics Co Ltd, Motorola Inc and others, is hoping to regain momentum in the fast-growing sector after a lackluster update to its mobile software in October.

The overhaul of Microsoft's phone technology comes as it hemorrhages market share in the burgeoning smartphone market, which many see as the key to the future of communication and media.

Microsoft took just an 8.8 percent of the global smartphone operating system market last year, according to technology analysis firm Canalys, down from 13.9 percent the year before.

It trails Symbian, the system used on Nokia phones, which has 47.2 percent of the market, RIM's BlackBerry with 20.8 percent and Apple's iPhone with 15.1 percent.

Microsoft also faces competition from Google Inc's new Android system, which already has a 4.7 percent share of the market.

(Reporting by Bill Rigby; editing by Andre Grenon)