Patent ID: 7120132

Claim:
A method for synchronizing a scrambling code in a CDMA (Code Division Multiple Access) communication system including a UTRAN (UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access Network) and a plurality of user equipments (UEs), using orthogonal codes for identifying the UEs and a single up-link scrambling code for the UEs to identify the UTRAN, and employing an uplink synchronous transmission scheme (USTS) where the UEs synchronize frames of uplink physical channels using the single scrambling code, wherein the UEs receive a signal providing system timing provided from the UTRAN and transmit a random access channel (RACH) signal based on the system timing, comprising the steps of: receiving, in the UTRAN, the random access channel signal from a UE to measure a propagation delay time (PD) of the UE, and transmitting a transmission time adjustment value calculated using the measured propagation delay time and a time offset τ DPCH,n between the system timing and a transmission time point of a downlink dedicated physical channel (DPCH); and determining, in the UE, a transmission time of the uplink physical channel signal by receiving the transmission time adjustment value, and scrambling a frame data with an orthogonal code and a scrambling code generated at a time being different from a generating time of the frame data with a scrambling code offset calculated from the transmission time adjustment value.