Nokia Siemens wins $1.55 bln Brazil deal with Oi

* NSN to operate Oi networks for 5 years

* Some 3,500 Oi staff to transfer to NSN

* NSN says deal profitable from year one

By Tarmo Virki, European technology correspondent

HELSINKI, July 16 (Reuters) - Nokia Siemens Networks [NSN.UL] said on Thursday it won a 1.1 billion euro ($1.55 billion) order to operate the networks of Brazilian telecom firm Oi (TNLP4.SA)(TNE.N) over the next five years.

Telecom operators across the world are increasingly looking at outsourcing the running of their networks to companies like Nokia Siemens Networks (NSN) and Sweden's Ericsson (ERICb.ST), which last week won $4.5-5 billion deal with Sprint [ID:nN09472369]

NSN, a joint venture between Nokia (NOK1V.HE) and Siemens (SIEGn.DE), said the deal makes it by far the top supplier in Latin America, cementing its position in what is a growing market.

"It very meaningfully opens up the market," Rajeev Suri, the head of NSN services operations, told Reuters in an interview.

Deals like this are crucial for Western vendors Ericsson, NSN and Alcatel-Lucent (ALUA.PA), which are battling Chinese rivals such as Huawei [HWT.UL] and ZTE (0763.HK) that have gained ground through aggressive hardware pricing.

Market share changes in the telecoms gear market have traditionally been slow, but Suri said new large outsourcing deals enable quicker shifts.

Outsourcing networks lets operators reap scale savings, as vendors like Ericsson and NSN manage hundreds of millions subscribers in hundreds of networks. This scale also makes it harder for new entrants to crack the managed services market.

"It's about (the) three of us," Suri said. (Reporting by Tarmo Virki; editing by John Stonestreet)