The present disclosure relates to a user device and a network node. The user device comprises a transceiver configured to broadcast an access signal SA when not being connected to any radio communication networks, receive an access response signal SR in response to broadcasting the access signal SA, communicate with at least one network node of the radio communication network. The network node comprises a transceiver and a processor; wherein the transceiver is configured to receive a broadcasted access signal SA, wherein the broadcasted access signal SA comprises identity information of the user device; wherein the processor is configured to assign at least one frequency spectrum segment for communication for the user device; and wherein the transceiver is further configured to transmit an access response signal SR to the user device.