The present invention refers to channel estimation in a communications network. According to the present invention, first two reference signals are transmitted by a base station to a set of mobile nodes in said communications network, wherein said base station includes first two antenna ports and wherein each of said first two reference signals refers to one antenna port of said first two antenna ports. Further, at least one second reference signal is transmitted by said base station to a cooperating mobile node, wherein said cooperating mobile node is included in said set of mobile nodes; said cooperating mobile node is assigned to a cooperation area in said communications network, said cooperation area being defined by said base station; and said at least one second reference signal refers to a corresponding further antenna port of further antenna ports included in said base station.