Patent ID: 7120137

Claim:
A radio communication method of a mobile station used for a radio communication system employing CDMA (Code Division Multiple Access) for radio access and providing multi-rate transmission, the radio communication system including a base station controlling apparatus, a plurality of base stations, and a plurality of mobile stations, the mobile station being one of said plurality of mobile stations, the radio communication method comprising steps of: receiving code information by message from the base station controlling apparatus or from one of said plurality of base stations, said code information for switching a first code being used to a second code; receiving timing information by message, said timing information including an integer representing a frame at which the first code is switched to the second code; switching from the first code to the second code based on the code information and the timing information received, said step of switching performed in synchronization with switching from the first code to the second code at the one of the plurality of base stations; and transmitting a completion message from said mobile station to the base station controlling apparatus or to the one of said plurality of base stations to indicate completion of the step of switching from the first code to the second code, wherein the timing information is used to synchronize the switching at the mobile station with the switching at the one of plurality of base stations.