A mobile communication method, a base station and a mobile communication system employing a hierarchical virtual antenna architecture are disclosed. The method comprises steps of: negotiating, by a first base station, with a second base station about a transmission mode with a mobile station; and according to the negotiated transmission mode, negotiating, by the first base station, with the second base station about respective demodulation reference signal frequency pattern allocation and measurement reference signal frequency pattern allocation in the hierarchical virtual antenna architecture. The flexible and effective reference signals may be realized in various multi-cell Multiple-Input Multiple-Output (MIMO) operation modes by the method.