Likewise, the object of the disclosure is obtained by a network node that is configured for operation in a first network for designating one or more cells of a second network as neighbouring cells to the first network. The radio network node comprises radio circuitry arranged for transmission and reception of radio signals. The radio network node further comprises processing circuitry configured to cause the network node to select a set of carriers employed in the second network and to transmit, using the radio circuitry, information for the selected set of carriers to a wireless device served by a cell of the first network. The radio network node receives, using the radio circuitry, measurement reports for respective carriers from the wireless device and determines neighbour cell relations between the first network and one or more cells of the second network based on the received measurement reports.

The network node and the computer program has the corresponding advantages of those described above in relation to the method performed in a network node.

The object to improve traffic distribution between a first network and a second network, e.g., respective macro and micro cellular networks, is also obtained by a method, performed in a wireless device served by a cell of a first network, for designating one or more cells of a second network as neighbouring cells to the first network. The method comprises receipt, from said network node of the first network, information on a set of carriers employed in the second network and performing measurements on selected one or more carriers from the set of carriers. The method further comprises transmission of measurement reports for respective carriers to the network node, the measurement reports being representative of neighbour cell relations between the wireless device serving cell and one or more cells of the second network.