Disclosed is a method for transmitting a dedicated physical data channel signal over a dedicated physical data channel in the absence of transmission data to be transmitted over the dedicated physical data channel in order to properly maintain a target SIR (Signal-to-Interference Ratio) when there exists new transmission data after the absence of the transmission data in a CDMA (Code Division Multiple Access) mobile communication system. The method comprises generating a dummy bit generation request signal in the absence of the transmission data; and upon receipt of the dummy bit generation request signal, generating a dummy bit stream, and transmitting a dedicated physical data channel signal created by attaching the CRC bit stream to the dummy bit stream.