Cellular radio system using CDMA scheme
First 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; and
first 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.
1 Assignment
0 Petitions
Accused Products
Abstract
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.
205 Citations
22 Claims
-
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; and first 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. 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 via a CDMA radio channel and in which a plurality of radio frequencies are divided into a first radio frequency group including a plurality of radio frequencies and a second radio frequency group including a plurality of radio frequencies, the radio frequencies 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 radio frequencies belonging to the second radio frequency group; and handoff control means for monitoring traffic amounts of said plurality of radio frequencies belonging to the first radio frequency group and effecting the hard handoff control for averaging the traffic amount of said plurality of radio frequencies belonging to the first radio frequency group with respect to the mobile station based on the result of monitoring.
-
-
10. 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:
-
monitoring means for monitoring movement of the mobile station; estimating means for estimating a probability that the mobile station will move from a coverage area of a first base station group to a coverage area of a second base station group based on the result of monitoring by said monitoring means; radio frequency assigning means for assigning the at least one radio frequency belonging to the first radio frequency group to the mobile station if the mobile station is estimated to have a high probability of moving into the coverage area of the second base station group by said estimation means, and assigning a radio frequency belonging to the second radio frequency group to the mobile station if the mobile station is estimated to have a low probability of moving into the coverage area of the second base station group; and first handoff control means for effecting a control operation for soft handoff if a radio frequency assigned to the mobile station is the at least one radio frequency belonging to the first radio frequency group when the mobile station moves from the coverage area of the fix base station group to the coverage area of the second base station group, and effecting a control operation for hard handoff if the radio frequency assigned to the mobile station is a radio frequency belonging 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. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. A radio communications apparatus for use in a CDMA cellular radio system including a plurality of base station groups each including a plurality of cells formed by a plurality of base stations, wherein a first radio frequency group includes at least one radio frequency and a second frequency group includes a plurality of radio frequencies and the at least one radio frequency of the first radio frequency group is commonly allocated to all of the base station groups and the radio frequencies of the second radio frequency group a individually allocated to the plurality of base station groups, comprising:
-
first frequency selection means for selecting an available radio frequency from the first radio frequency group in accordance with turning ON of a power source; and second frequency selection means for, if a radio frequency from the first radio frequency group cannot be selected by the first frequency selection means, selecting an available radio frequency from the second radio frequency group allocated to the base station of a cell where a mobile station is situated, wherein a radio path is created from the mobile station to the base station of the cell where the mobile station is situated through the use of a radio frequency selected by the first frequency selection means or second frequency selection means. - View Dependent Claims (21)
-
-
22. 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 assigned in common to all of the base stations belonging to at least one 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, the CDMA cellular radio system comprising:
-
radio frequency assigning means for assigning the at least one 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; and first 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.
-
Specification