A method performed by a network node for managing transmission of Cell Reference Symbols, CRS, wherein the network node operates one or more cells and the network node is configured to transmit the CRS in a first bandwidth mode. When the network node has identified a cell which is not actively serving any UEs, also referred to as an empty cell, the network node applies a reduced CRS bandwidth mode in the first cell in relation to the first bandwidth mode. By applying a reduced CRS bandwidth mode in the empty cell, the overall interference of the CRS from the empty cell is reduced, thereby enhancing the performance in cells actively serving UEs.