Patent ID: 7203510

Claim:
A method of controlling transmission power in a CDMA mobile communication system wherein an uplink signal target SIR value that serves as the reference in closed-loop transmission power control is updated in a base transceiver station, said method comprising the steps of: when a loss of synchronization of a user signal from a mobile station is detected, adding a predetermined step value ΔSIR to an uplink signal target SIR value that has been reported from a base station controller and making the result an uplink signal target SIR provisional value; if this uplink signal target SIR provisional value is smaller than an uplink signal target SIR maximum value that has been set in advance, updating the uplink signal target SIR value that serves as the reference for closed-loop transmission power control to said uplink signal target SIR provisional value; comparing said uplink signal target SIR provisional value with a value obtained by adding the uplink signal target SIR value (RNC: Radio Network Controller) that is set from said base station controller to a threshold value α that has been set in advance; transmitting an uplink signal target SIR value update message to said base station controller when said uplink signal target SIR provisional value is greater than the value obtained by adding the uplink signal target SIR value (RNC) that was set from said base station controller to threshold value α; and upon receiving an uplink signal target SIR value report message from said base station controller, updating the uplink signal target SIR value that serves as the reference in closed-loop transmission power control to a new uplink signal target SIR value (RNC) that has been reported by means of the uplink signal target SIR value report message.