Power control apparatus and method with interference reduction during soft handoff in CDMA cellular communication systems

A structure of a mobile station for power control of forward links in soft handoff in a CDMA cellular mobile communication system, comprising:

• an automatic gain control unit to control gains of signals received from base stations;
• a digital demodulator to demodulate user information of received signals whose gains are controlled through said automatic gain control unit;
• a deinterleaver/a decoder to decode said demodulated and received signals and to correct errors in the signals;
• an encoder/an interleaver for efficient coding of said received signals;
• a receiving signal measurement part to measure signal-to-noise ratio, combined signal-to-noise ratio and pilot signal-to-noise ratio for each base station by said digital demodulator;
• a power control part to transmit the transmit power decrease request information for forward traffic channels to all base stations engaged in handoff if the combined signal-to-noise ratio is larger than the target value for power control, to transmit power increase request information only to a base station whose pilot signal-to-noise ratio is the largest and to transmit power decrease request information to the rest of the base stations if the combined signal-to-noise ratio is smaller than the target value for power control, after comparing results of said receiving signal measurement part with the target value for power control;
• a spread spectrum modulator to modulate encoded signals, using outputs of said coder/interleaver and said power control part;
• and
• a variable transmit power amplifier to control transmit power of said modulated signals.