The present invention presents a method and a controller for selecting the type of connection used to connect a terminal device to a serving base station. The connection type is selected on the basis of monitored communication-environmental parameters of the terminal device. The selection is made between a direct cellular radio connection and a relayed cellular radio connection. The relayed connection is established through another terminal device acting as a relay terminal for the connection being relayed. A direct device-to-device link between the two terminal devices is established as a cognitive radio connection, and a radio access technology and communication parameters of the device-to-device link may be negotiated between the terminal devices. The relay terminal then links the device-to-device link to a direct cellular radio connection between the relay terminal and the serving base station.