초록 ▼

In a CDMA cellular radio system a plurality frequencies of the system are divided into frequencies belonging to a first group and frequencies belonging to a second group, all of the frequencies of the first group are commonly assigned to all of the base stations BS1 to BSn and the frequencies of the

In a CDMA cellular radio system a plurality frequencies of the system are divided into frequencies belonging to a first group and frequencies belonging to a second group, all of the frequencies of the first group are commonly assigned to all of the base stations BS1 to BSn and the frequencies of the second group are individually assigned to the base station groups BSa to BSc. The frequency in the first group is preferentially assigned to a mobile station MSj, and when the mobile station MSj moves between the cells of the different base station groups, soft handoff is effected by using the frequency in the first group. Further, the rates of use of channels of the respective assigned frequencies are monitored for the respective base stations BS1 to BSn, and when a frequency corresponding to the rate of use of the channel which has exceeded a threshold value is detected, the idle handoff control is effected with respect to the mobile station which uses the above frequency.

대표청구항 ▼

[ I claim:] [1.] A CDMA cellular radio system which includes a plurality of base station groups each including a plurality of cells formed by a plurality of base stations, and a mobile station connected to at least one of said plurality of base stations of the base station groups via a CDMA radio ch

[ I claim:] [1.] A CDMA cellular radio system which includes a plurality of base station groups each including a plurality of cells formed by a plurality of base stations, and a mobile station connected to at least one of said plurality of base stations of the base station groups via a CDMA radio channel, and in which a plurality of radio frequencies are divided into a first radio frequency group including at least one radio frequency and a second radio frequency group including a plurality of radio frequencies, the at least one radio frequency of the first radio frequency group being commonly assigned to all of the base stations of said plurality of base station groups and the radio frequencies of the second radio frequency group being individually assigned to said plurality of base station groups, comprising:radio frequency assigning means for assigning a radio frequency belonging to the first radio frequency group to the mobile station in preference to the radio frequencies belonging to the second radio frequency group; andfirst handoff control means for effecting a control operation for soft handoff if a radio frequency assigned to the mobile station belongs to the first radio frequency group when the mobile station moves from a coverage area of a first base station group to a coverage area of a second base station group, and effecting a control operation for hard handoff if the radio frequency assigned to the mobile station belongs to the second radio frequency group when the mobile station moves from the coverage area of the first base station group to the coverage area of the second base station group.