Mobile station and a method of reducing interference among radio channels in the mobile station

A method of controlling transmission power in a CDMA cellular mobile radio communication system which comprises a plurality of base stations each of which transmits a pilot signal preassigned to each base station and a plurality of mobile stations communicable with the base stations, each of the mobile stations comprising first transmission power control means for adjusting the transmission power on the basis of a reception level concerned with the pilot signals and second transmission power control means for controlling the transmission power by a control step size on the basis of a control instruction sent from the base stations under connection, comprising the steps of:

• receiving the pilot signals from the plurality of the base stations;
• determining the transmission power in inverse proportion to a maximum one of reception levels of the pilot signals;
• judging whether or not a first reception level of the pilot signals concerned with the base stations under connection exceeds a second reception level of the pilot signals concerned with the base stations under non-connection to produce a result of judgement;
• and
• changing the control step size from one to another when the second reception level exceeds or does not exceed the first reception level.

A method of controlling transmission power in a CDMA cellular mobile radio communication system which comprises a plurality of base stations each of which transmits a pilot signal pre-assigned to each base station and a plurality of mobile stations communicable with the base stations, each of the mobile stations comprising first transmission power control means for adjusting the transmission power on the basis of a reception level concerned with the pilot signals and second transmission power control means for controlling the transmission power by a control step size on the basis of a control instruction sent from the base stations under connection, comprising the steps of:

• receiving the pilot signals from the plurality of the base stations;
• determining the transmission power in inverse proportion to a maximum one of reception levels of the pilot signals;
• judging whether or not a first reception level of the pilot signals concerned with the base stations under connection exceeds a second reception level of the pilot signals concerned with the base stations under non-connection to produce a result of judgement;
• minimizing the transmission power at every time interval for a predetermined time period when the second reception level exceeds the first reception level;
• and
• executing a control operation by the use of the first and the second transmission power control means either during a time period except the predetermined period or when the second reception level does not exceed the first reception level.

A method of controlling transmission power in a CDMA cellular mobile radio communication system which comprises a plurality of base stations each of which transmits a pilot signal pre-assigned to each base station and a plurality of mobile stations communicable with the base stations, each of the mobile stations comprising first transmission power control means for adjusting the transmission power on the basis of a reception level concerned with the pilot signals and second transmission power control means for controlling the transmission power by a control step size on the basis of a control instruction sent from the base stations under connection, comprising the steps of:

• receiving the pilot signals from the plurality of the base stations;
• determining the transmission power in inverse proportion to a maximum one of reception levels of the pilot signals;
• judging whether or not a first reception level of the pilot signals concerned with the base stations under connection exceeds a second reception level of the pilot signals concerned with the base stations under non-connection to produce a result of judgement;
• decreasing the transmission power in the mobile station by a predetermined amount at every preselected time interval when the second reception level of the pilot signals exceeds the first reception level;
• and
• executing a control operation by the use of the first and the second transmission power control means either during the preselected time interval or when the second reception level does not exceed the first reception level.

A method of controlling transmission power in a mobile station in a CDMA cellular mobile radio communication system, comprising the steps of:

• detecting each pilot signal level from a plurality of base stations;
• checking out whether or not the base stations are under connection to discriminate between a first group of the base stations under connection and a second group of the base stations under non-connection;
• and
• reducing the transmission power in the mobile station to suppress an increase of the transmission power in the mobile station when a first reception level concerned with the first group of the base stations does not exceed a second reception level concerned with the second group of the base stations.