Nokia CEO Stephen Elop believes the company has successfully accelerated its product development – but continues to face challenges over the coming months.

“Over the last year, we’ve changed the clock speed of Nokia – we’re getting more done, more great products coming out that meet the needs of consumers,” Elop told Mobile World Live in an exclusive interview at Mobile World Congress.

However, he also acknowledged that Nokia is still undergoing a major transition, with rapid new product introductions and teams being moved to support its new strategy – which means that “we still have a lot of work to do.”

“We have to continue to execute quickly and very well. We just have to religiously execute on that pattern in the year ahead and good fortune will arise from that,” the executive said.

In February 2011, Elop unveiled Nokia’s new strategy of working closely with Microsoft to move its smartphone portfolio to Windows Phone, along with plan for a significant restructure. The company unveiled its first Windows Phone handsets (the Lumia 800 and 710) in October and has since added the Lumia 900 and 610 to the line-up.

Elop said the past 12 months had been a challenging year with “significant company changes”, but that the company is proud of what it has accomplished during the period.

In January 2011, Nokia announced it had sold more than a million Lumia devices using the Windows Phone platform. But this was tempered by forecasts that it would sell fewer Symbian-based devices than it had originally anticipated. Elop said at the time that 2012 would “continue to be a year of transition.”

Watch the full video here.