Method for transmitting parameter use handoff to synchronous cell site from asynchronous cell site in a mobile communication system

PURPOSE: A method for transmitting parameters necessary for the handoff between a synchronous BS(Base Station) and an asynchronous BS in a mobile communication system is provided to transmit synchronous BS information(long code state), necessary to execute a handoff to a synchronous BS from a third generation asynchronous W-CDMA BS, to a mobile station through an asynchronous channel using an external time reference. CONSTITUTION: In the state that a new physical channel is set up between a mobile station and an asynchronous BS(S101) and the mobile station keeps connected with the asynchronous BS(S102), the mobile station transmits power monitoring information for adjacent BSs to the connected asynchronous BS(S103). Receiving power monitoring information, the asynchronous BS judges whether an asynchronous BS to hand off exists among the neighboring BSs(S104). In case that an asynchronous BS to hand off doesn't exist, the mobile station transmits a handoff request signal to a synchronous BS(S106). Then the mobile station receives an offset value, indicating the difference between asynchronous frame timing obtained through an external time reference from the asynchronous BS and the zero offset timing of the synchronous BS(S107). Then the mobile station receives a compressed mode message from the asynchronous BS(S108). In the compressed mode, the mobile station measures the pilot strength of neighboring synchronous BSs using received offset information and reports a result to the connected asynchronous BS(S109). The mobile station receives long code state information through an existing channel or the new physical channel(S110). The mobile station executes the handoff to a synchronous BS, obtained after reviewing the report of the mobile station, using long code state information(S111).