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Abstract

A code-division-multiple-access (CDMA) system employing spread-spectrum modulation. The CDMA system has a base station (BS), and a plurality of subscriber units. The signals transmitted between the base station and subscriber unit use spread-spectrum modulation. The improvement method for adaptive forward power control (APC) from a base station (BS) to a subscriber unit (SU), comprises the steps of sending from the base station, using spread-spectrum modulation, a BS-spreading code on a forward channel. The subscriber unit despreads the BS-spreading code on the forward channel as a despread signal, determines a first power level P.sub.d which includes power of the despread signal plus noise and a second power level P.sub.N, which includes despread-noise power. The subscriber unit determines a first error signal e.sub.1, from the first power level P.sub.d, the second power level P.sub.N, and a required signal-to-noise ratio SNR.sub.REQ for service type, and a second error signal e.sub.2, from a measure of total received power P.sub.r and an automatic gain control (AGC) set point P.sub.o. The subscriber unit forms a combined error signal from the first error signal e.sub.1, the second error signal e.sub.2, a first weight a.sub.1 and a second weight a.sub.2, and hard limits the combined error signal to form a single APC bit. The APC bit is transmitted to the base station. In response to the APC bit, the base station adjusts transmitter power to the subscriber unit.

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