A method performed by a network node (160) includes serving a cell area by a first physical network node for a first time duration. The first physical network node uses an identifier of a logical network node. For a second time duration, the cell area is served by a second physical network node. The second physical network node uses the identifier of the logical network node. The first physical network node serves the cell area with a first frequency band and the second physical network node serves the cell area with a second frequency band.