Ad funded MVNO Blyk announced plans to expand into Belgium on Thursday, tapping Nokia Siemens Networks to host its core network.

Blyk, which launched its first services in the UK just over a year ago, is unusual no just in the fact that it has an ad funded business model, but also in that it owns a good portion of its own infrastructure despite being an MVNO.

As a result, the Finnish headquartered company has chosen Nokia Siemens Networks to host its core network as it expands into the Netherlands and Belgium. Under two turnkey service deals, NSN will provide the infrastructure, prepaid charging and messaging systems, software and operations to Blyk as a fully managed, hosted service to Belgium and the Netherlands.

Blyk piggybacks on Orange’s network in the UK, and in January revealed Vodafone as its Dutch partner. In Belgium, the company will team up with Mobistar, and recently confirmed plans to move into Spain and Germany.

Despite some scepticism, Blyk has made waves in the industry, last month announcing the doubling of its member base in the UK to 200,000 since autumn 2007. The company runs an advertising funded mobile service aimed at 16-24 year olds, providing free text messages and calls to subscribers who receive advertisements on their phones.

The company has also raised eyebrows over its claimed average advertising response rates of 29 per cent. Compared to other forms of mass market advertising this figure is phenomenal, stacked against a 0.5 per cent response rate for online advertising and 4.5 per cent from unprofiled SMS.