A system for mobile communication, based on code division multiple access includes base stations, each of which communicates with mobile stations by using a plurality of radio frequencies covering respective cells, the respective cells including a first cell covered by a first radio frequency and a second cell covered by a second radio frequency. The system further includes a base-station controller which communicates with the base stations, and controls the mobile stations to switch from the first cell of a first base station to the first cell of a second base station via a soft hand-off operation and switch between the first cell and the second cell within any base station via a hard hand-off operation, the base-station controller providing the mobile stations with no direct switch between the second cell of the first base station and the second cell of the second base station.