TeliaSonera CEO Johan Dennelind this week issued a rallying cry to mobile operators: fight back against the OTT threat.

"We are being attacked every day, every second," Dennelind said at a press event at Mobile World Congress. These 'attackers' are other companies that "want our customer base," he warned.

"We're shrinking in relevance and we need to fight back," Dennelind insisted.

Essentially, his message to operators is that they need to attack the market, rather than simply defend their position. They must widen their approach, offering services that customers will be willing to pay for rather than making money solely from connectivity.

"It's up to us to prove we can do relevant innovation," he said, making reference to TeliaSonera's partnership with music streaming service Spotify. "[We must] explore the opportunities to get into different revenue streams and customer loyalty as well," Dennelind said.

That's not to say that mobile operators cannot generate revenues from the mobile data traffic they carry on their networks though.

"We're starting to find a formula where we can monetise data," Dennelind said. In Denmark, Norway and Finland TeliaSonera's customers get free voice and SMS but pay for the amount of data they use, he explained. Mobile data traffic grew by 60% in 2013 and the telco is able to monetise a higher percentage of that than it could the previous year.

"We need to entice customers to use more and pay more," Dennelind said.

One way to do that is by capturing a larger share of the customer's wallet through converged service offerings.

In Sweden TeliaSonera is working on extending its fixed infrastructure as close as possible to customers. It will invest SEK5 billion (€560 million) in 4G and fibre in its home market in the next few years.

But it does not own fixed infrastructure in all the markets in which it operates. In Spain, for example, where its Yoigo mobile unit has just reached the 4 million mark, it has brokered a network-sharing deal with Telefonica that enables it to offer fixed and broadband products alongside mobile.

"I would like to have all the capabilities that everyone else has, but we don't," admitted Dennelind.