IDC predicts the WW smartphone market will grow by 55% Y-o-Y in 2011, with shipments reaching 472m units-- a figure the analyst predicts will nearly double to reach 982m units in 2015.

WW smartphone shipments in 2010 total around 305m units. 

Fuelling the smartphone market's growth is falling average selling prices, increased phone functionality and lower-cost data plans, amongst other factors-- all making smartphones more accessible to a wider customer range. 

The analyst expects Android to grow by more than 40% in 2011's second half, with a "significant and growing" number of vendors propelling such growth-- and its becoming top mobile OS WW in Q4 2010.

Symbian, meanwhile, continues losing market share as top supporter Nokia moves towards Windows Phone 7 (even if it commited itself to support Symbian until 2016). 

iOS is 2011's 3rd ranking OS-- one IDC expects will grow at a relatively modest pace as the smartphone market matures and diversified. The analyst also predicts some decline in market share for Apple's OS in the 2011 - 2015 period, even if still it still expects iOS shipment volume growth to be "significant". 

IDC predicts Windows Phone 7 will achieve the number 2 rank by 2015-- barring any obstacles in Nokia's transition to the OS. High volume WP7 growth will only really kick off once Nokia starts shipping its WP7 devices, particularly as Mango-powered devices by other vendors will only be available by late 2011. 

Finally Blackberry OS will maintain its number 4, even if it will see some market share decline through the 2011 - 2015 period as shipment volumes grow. 

Go IDC Worldwide Quarterly Mobile Phone Tracker

The WW mobile device market totals 427.8m units for Q1 2011 with 19% Y-o-Y growth, according to Gartner-- a market where the smartphone segment continues to grow rapidly to soon outpace the rest. 

Smartphones account for 23.6% of the mobile device market in Q1 2011, growing by 85% Y-o-Y-- and it will only continue growing further, thanks to competitive mid-tier models which Gartner predicts will drive the smartphones towards mass adoption. 

Nokia retains its position as WW mobile device market's leading vendor-- even if its market share (of 25.1%) is at its lowest since 1997 after losing 5.5% market share Y-o-Y. Gartner predicts it will aggressively lower ASPs further in order to maintain Symbian device shipments before its first Windows Phone 7 models start hitting the market. 

Samsung meanwhile has its strongest first quarter ever (reaching 16.1%% market share) and should continue going strong in Q2 2011, thanks to a number of device announcements, including new Galaxy smartphone and tablet models. 

Following in third place is LG, reaching 5.6% market share. 

Moving to the current smartphone OS wars, Android has 36% market share, with Symbian following with 27.4%. However, Gartner says the quarter's biggest news is that of Nokia and Microsoft's alliance, which ties directly with Symbian's retirement (which will lead to a competitors' rush to capture its market share). 

Meanwhile RIM's transition to the QNX platform in 2012 should make its smartphones more attractive in the graphics, performance and touch departments, while unifying its Blackberry and Playbook experience. 

Windows Phone's share and sales remain quite modest, reaching 1.6m units in Q1 2011-- but the platform should start gaining further momentum once Microsoft's partnership with Nokia starts seeing actual fruit (in the shape of new device models). 

Gartner however advices vendors to exercise caution, as it forecasts dropping sales (alongside softness in user demand in emerging markets) through Q2 2011.

Go Gartner Says 428 Million Mobile Communication Devices Sold Worldwide in Q1 2011

Pyramid Research predicts the Windows Phone establish itself as the smartphone OS market leader as early as 2013, partly thanks to Microsoft's alliance with Nokia, which should show its true force by that very year. 

The reasoning goes that Nokia, while currently appearing to suffer losses through its dragging on with Symbian, is also strong enough to take a beating-- as well as smart enough to learn from both Symbian and Android's (not to mention iOS') successes and failures. 

Thus, when Nokia finally releases its WP7 models it will do so with enough confidence to jump start a new era for the OS. 

Android's growth is also set to start slowing down (compared to the 2010 - 2012 period). 

Meanwhile RIM and Apple's insistence on closing their operating systems anything but their own hardware will result in their own losing out to the larger manufacturers  (such as Samsung and LG), who have the luxury to benefit from the economies of scale. 

The analyst says its forecast model takes 51 different countries into account-- including a large number of emerging market which it says will drive and determine market growth in the next 5 years. 

Go Why Windows Phone Will Beat Android

EMEA is at the second place when it comes to WW regional shares, accounting for 32% of worldwide shipments, with 32.6m units-- showing 67% Y-o-Y growth, Canalys says. 

Meanwhile overall smartphone shipments grow by 83% Y-o-Y, reaching 101m units for Q1 2011. 

Nokia retains its position as WW market leader, shipping 24.2m units (with 13% Y-o-Y growth), but is under strain from vendors selling Android-carrying smartphones. Canalys says Samsung's mid-tier priced Wave smartphones have good uptake in France, the UK and Germany. 

Following Nokia in smartphone shipments are Apple, RIM, Samsung and HTC-- same as Q4 2010. RIM however continues losing market share, as it awaits its portfolio refresh (due to its focusing on launching the Playbook tablet). 

Go Canalys Smartphone Analysis Service