BARCELONA (Reuters) -- More and more mobile operators are betting on upgrades to their third-generation (3G) networks, hoping to ride a booming market for services such as music downloads and fend off threats from new technologies.

Wireless broadband was a key theme at the mobile industry's biggest annual trade show in Barcelona this week, as one operator after another unveiled plans to roll out HSDPA, a technology that can offer Internet speeds at least four faster than the present WCDMA 3G standard.

"It's not just another buzzword. It is here, it's real," said T-Mobile Chief Executive Rene Obermann, as the Deutsche Telekom unit announced plans to roll out HSDPA in Germany, Austria and the Netherlands during this quarter.

T-Mobile rivals Vodafone, Orange are among many others planning to roll out the technology. Most operators initially plan to launch data cards aimed at corporate users.

Mobile phone services to consumers are set to follow later this year or next year when more handsets become available.

The latest push by operators to lure more customers to higher-paying 3G services comes as rising competition in mature European markets along with falling prices erode existing revenue streams, leaving them with little choice but to look to boost revenues from new services.

Operators in Europe spent billions of euros on 3G networks, which they hoped would fetch them many more billions in additional revenues from services such as Internet surfing and video calling.

But take up of these services has proved elusive, and even though the new networks have been around for a few years now, operators continue to depend on voice calls and text messages for the bulk of their revenues.

This is partly because Internet speeds on existing 3G networks are at best only around 384 kilobits per second, while rival wireline technologies offer several times that.