With more than 1 billion phones sold globally for the first time, 2007 was a banner year for mobile phone sales. As sales continue to grow, the big questions this year are whether global market leader Nokia can expand in North America, and whether Motorola can stop its slide.

Worldwide sales of mobile phones surpassed 1.15 billion units in 2007, a 16% increase from 2006 sales of 990.9 million, according to figures from Gartner.

Emerging markets, especially China and India, are now the driver for growth, with many people in the countries now buying their first phone.

Nokia continues to dominate. It sold 435 million mobile phones last year, and gained a market share of more than 40% for the first time during the fourth quarter, according to Gartner. During 2007 Nokia's market share was 37.8%.

It is followed by Motorola, >Samsung, >Sony Ericsson and >LG. Everyone except for Motorola, which lost its second place to Samsung during the fourth quarter, increased its market share.

For the full year Motorola's market share was 14.3%, down from 21.1%.

Samsung increased its market share from 11.8% to 13.4%.

Sony Ericsson and LG saw their share increase by less than 1%, to 8.8% and 6.8%, respectively.

Looking forward to this year, sales will continue to grow, according to Gartner. Nokia has the chance to extend its lead even further, with growth in North America the key.

"In most markets Nokia's market share is larger than 40%, in North America it's close to 10%," said Carolina Milanesi, research director at Gartner.

The Finnish phone giant has tried, and failed, to crack the North American market for many years. But changes in the market will help Nokia, according to Milanesi.

"Verizon has said it plans to open its network, which might be more on paper than in reality. But North American carriers are starting to realize they need to be more flexible than in the past. For Nokia, and everyone else, it means not having to build Verizon-specific phones, and faster time to market," she said.

In 2008, Nokia will also need to continue to improve its portfolio, offering not only more applications and functions, but also novel designs and improved user interfaces.

Nokia has recently received criticism for not releasing phones equipped with touch-based user interfaces.

The IDG News Service is a Network World affiliate.