The present invention concerns a method of providing communication over a mobile communication network (1) and components for providing communication over the communication network (1). The network (1) includes two or more fixed nodes (2a, 2b) each operating a fixed radio cell (3a, 3b) for serving one or more user equipments (4) via a first radio interface (5a, 5b). Each of these fixed radio cells (3a, 3b) is identified by a physical cell ID (6a, 6b) selected out of a set of N physical cell IDs. In addition, the network (1) includes one or more mobile relay nodes (7) served by the one or more fixed nodes (2a, 2b) via a second radio interface (8a, 8b). The mobile relay nodes (7) each operate a mobile radio cell (9) for serving one or more user equipments (4) via a third radio interface (10). Each of these mobile radio cells (9) is identified by a physical cell ID (6c) selected out of the set of N physical cell IDs. The method includes the step of dynamically assigning a physical cell ID (6c) of the set of N physical cell IDs to the one or more mobile radio cells (9).