Code-division-multiple-access mobile communication system accommodating increased number of mobile stations

Abstract

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.

1 .- 12 . (canceled)  
   
   
       13 . A base station which forms a first area and a second area by utilizing a first frequency and a second frequency, respectively, used in common with an adjacent base station, comprising a radio unit configured to set the first area such that the first area overlaps an area that is formed by the adjacent base station by use of the first frequency, and to set the second area smaller than the first area such that the second area is formed within the first area, wherein soft handover from the adjacent base station using the first frequency used in common is permitted, and handover from the adjacent base station using the second frequency used in common is not permitted.