Nokia today said it has launched its first trial of unlicensed mobile access technology in Oulu, Finland, putting its new Nokia 6136 dual-mode phones in the hands of 50 families and using Oulu’s free downtown hotspot network.

UMA allows seamless handoff between a WLAN hotspot and the cellular network, tunneling the GSM signal through the wireless IP network to a fixed-mobile convergence gateway on the carrier’s network. “This pilot project in an important step forward in bringing functional UMA technology to the mass market,” said Peter Ropke, Nokia senior vice president for mobile phones R&D, said in a statement.

Carriers are investigating UMA as way to offload minutes from overtaxed voice networks, using public unlicensed-spectrum networks to handle growing traffic they would normally have to acquire new spectrum to support. Nokia did not say how long the pilot would last, nor if it would be expanded beyond its current limited scope.