Nokia Siemens Networks on Wednesday agreed to pay $205 million to acquire Apertio, a United Kingdom-based maker of databases that consolidate mobile and wireline subscriber data on common servers.

The hefty price-tag for five-year-old Apertio, which has taken about $40 million in investments from Deutsche Venture Capital and Motorola Ventures among others, demonstrates the growing demand among carriers for flexible subscriber databases.

Apertio was among the first wave of startups to hop on the fixed/mobile convergence bandwagon, choosing to provide network operators with a common, open standards-based place to access and manipulate all of their subscriber data.

Large network operators have traditionally tended to compartmentalize their subscriber data in expensive proprietary databases that made the marketing of new services a complex and expensive undertaking.

The quickening pace of innovation in the telecommunications market is driving demand for centralized, secure subscriber databases that allow carriers to quickly add new applications with easy access to subscriber data, according to NSN.

"We've been working with Apertio for a couple of years now and found that the technology was at least a year ahead of what we or anyone else had in their labs," said Michael Clever, head of next-generation voice and multimedia business lines for NSN's Converged Core business unit.

Apertio's customers are primarily Europe-based carriers such as Orange, T-Mobile, Vodafone, and O2, but NSN said it is testing Apertio's technology with at least three U.S. carriers, one of which will be announced shortly.

Bristol-based Apertio is the second acquisition for NSN, a joint venture of Nokia and Siemens based in Espoo, Finland. The company, which started doing business in April 2007, announced its planned acquisition of Atrica, a metro Ethernet startup in October 2007. (See Nokia Siemens Hooks Atrica)