China Mobile, the world's largest mobile carrier by subscribers, expects to see booming demand for smartphones in the next few years, a senior company official said.

Bill Huang, general manager of China Mobile's research institute, said the firm sees smartphone sales growing in "double digits" in coming years, at least two-to-three times faster than other phone sales.

"Over next three-to-five years, 50 percent of our users will migrate to smartphones," Huang said. He said currently about 10 percent of the company's clients use smartphones.

The average selling price of smartphones is set to fall to below $150 from above $300 within one-to-two years, he said.

Mobile Internet plans bundled with 3G smartphones have been one of the fastest growing sources of revenue for most telecom operators, as the voice segment of the market becomes increasingly saturated and competitive.

China Mobile unveiled plans last month to sell 3G smartphones using a lower-cost cellphone platform called OPhone, developed by California-based Marvell Technology, in what it hopes will be a major advance for its 3G services.

The company continues to use Microsoft's Windows Mobile and Nokia's Symbian operating system, but the focus will be on its own software.

"We are very much focusing on developing the user experience on our own platform," Huang said on the sidelines of a telecoms conference in Geneva. "Winning customers' hearts is more important than winning customers' wallets."

To attract application developers, major global operators China Mobile, Vodafone, Verizon and Softbank are jointly working on creating middleware that allows applications to work on different operating systems.

China Mobile and Vodafone have opened services built on top of the middleware.