Apparatus for adaptive reverse power control for spread-spectrum communications
First Claim
1. An apparatus for adaptive reverse control of power (APC) from a subscriber unit (SU) to a base station (BS), comprising:
- said subscriber unit for sending to said base station, using spread-spectrum modulation, a SU-spreading code on a reverse channel;
said base station unit for despreading the SU-spreading code on the reverse channel as a despread signal, for determining a first power level Pd from the despread signal, whereby the first power level Pd includes the power of the despread signal plus noise, for determining a second power level PN, whereby the second power level includes the power of the despread noise, for determining a first error signal e1, from the first power level Pd, the second power level PN, and a required signal-to-noise ratio SNRREQ for service type, for determining a second error signal e2, from a measure of total received power Prt and an automatic gain control (AGC) set point Po, for forming a combined error signal from the first error signal e1, the second error signal e2, a first weight a1 and a second weight a2, with the first weight a1 and the second weight a2 chosen for each service type, for hard limiting the combined error signal to form a single APC bit, and for transmitting the APC bit to the subscriber unit; and
said subscriber unit for receiving the APC bit and, in response to the APC bit, for adjusting transmitter power to the base station.
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Accused Products
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 reverse power control (APC) from a subscriber unit (SU) to a base station (BS), comprises the steps of sending from the subscriber unit, using spread-spectrum modulation, a SU-spreading code on a reverse channel. The base station despreads the SU-spreading code on the reverse channel as a despread signal, determines a first power level Pd which includes power of the despread signal plus noise and a second power level PN, which includes despread-noise power. The base station determines a first error signal e1, from the first power level Pd, the second power level PN, and a required signal-to-noise ratio SNRREQ for service type, and a second error signal e2, from a measure of total received power Prt at the base station, and an automatic gain control (AGC) set point Po. The base station forms a combined error signal from the first error signal e1, the second error signal e2, a first weight a1, and a second weight a2, and hard limits the combined error signal to form a single APC bit. The APC bit is transmitted to the subscriber unit. In response to the APC bit, the subscriber adjusts transmitter power to the base station.
244 Citations
12 Claims
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1. An apparatus for adaptive reverse control of power (APC) from a subscriber unit (SU) to a base station (BS), comprising:
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said subscriber unit for sending to said base station, using spread-spectrum modulation, a SU-spreading code on a reverse channel;
said base station unit for despreading the SU-spreading code on the reverse channel as a despread signal, for determining a first power level Pd from the despread signal, whereby the first power level Pd includes the power of the despread signal plus noise, for determining a second power level PN, whereby the second power level includes the power of the despread noise, for determining a first error signal e1, from the first power level Pd, the second power level PN, and a required signal-to-noise ratio SNRREQ for service type, for determining a second error signal e2, from a measure of total received power Prt and an automatic gain control (AGC) set point Po, for forming a combined error signal from the first error signal e1, the second error signal e2, a first weight a1 and a second weight a2, with the first weight a1 and the second weight a2 chosen for each service type, for hard limiting the combined error signal to form a single APC bit, and for transmitting the APC bit to the subscriber unit; and
said subscriber unit for receiving the APC bit and, in response to the APC bit, for adjusting transmitter power to the base station. - View Dependent Claims (2, 3)
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4. An apparatus for adaptive reverse control of power (APC) from a subscriber unit (SU) to a base station (BS), comprising:
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subscriber means for transmitting, using spread-spectrum modulation, a SU-spreading code on a reverse channel;
base means for despreading the SU-spreading code on the reverse channel as a despread signal, for determining a first power level Pd from the despread signal, whereby the first power level Pd includes the power of the despread signal plus noise, for determining a second power level PN, whereby the second power level includes the power of the despread noise, for determining a first error signal e1, from the first power level Pd, the second power level PN, and a required signal-to-noise ratio SNRREQ for service type, for determining a second error signal e2, from a measure of total received power Prt and an automatic gain control (AGC) set point Po, for forming a combined error signal from the first error signal e1, the second error signal e2, a first weight a1 and a second weight a2, with the first weight a1 and the second weight a2 chosen for each service type, for hard limiting the combined error signal to form a single APC bit, and for transmitting the APC bit to the subscriber means; and
said subscriber means for receiving the APC bit and, in response to the APC bit, for adjusting transmitter power to the base means. - View Dependent Claims (5, 6)
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7. An apparatus for adaptive reverse control of power (APC) from a subscriber unit (SU) to a base station (BS), comprising:
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said subscriber unit for sending to said base station, using spread-spectrum modulation, a SU-spreading code on a reverse channel;
said base station unit for despreading the SU-spreading code on the reverse channel as a despread signal, for determining a first power level Pd from the despread signal, whereby the first power level Pd includes the power of the despread signal plus noise, for determining a second power level PN, whereby the second power level includes the power of the despread noise, for determining a first error signal e1, from the first power level Pd, the second power level PN, and a required signal-to-noise ratio SNRREQ for service type, for determining a second error signal e2, from a measure of total received power Prt and an automatic gain control (AGC) set point Po, for forming a combined error signal from the first error signal e1, the second error signal e2, a first weight a1 and a second weight a2, with the first weight a1 and the second weight a2 chosen for each service type, for converting the combined error signal to form an APC word, and for transmitting the APC word to the subscriber unit; and
said subscriber unit for receiving the APC word and, in response to the APC word, for adjusting transmitter power to the base station. - View Dependent Claims (8, 9)
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10. An apparatus for adaptive reverse control of power (APC) from a subscriber unit (SU) to a base station (BS), comprising:
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subscriber means for transmitting, using spread-spectrum modulation, a SU-spreading code on a reverse channel;
base means for despreading the SU-spreading code on the reverse channel as a despread signal, for determining a first power level Pd from the despread signal, whereby the first power level Pd includes the power of the despread signal plus noise, for determining a second power level PN, whereby the second power level includes the power of the despread noise, for determining a first error signal e1, from the first power level Pd, the second power level PN, and a required signal-to-noise ratio SNRREQ for service type, for determining a second error signal e2, from a measure of total received power Prt and an automatic gain control (AGC) set point Po, for forming a combined error signal from the first error signal e1, the second error signal e2, a first weight a1 and a second weight a2, with the first weight a1 and the second weight a2 chosen for each service type, for converting the combined error signal to form an APC word, and for transmitting the APC word to the subscriber means; and
said subscriber means for receiving the APC word and, in response to the APC word, for adjusting transmitter power to the base means. - View Dependent Claims (11, 12)
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Specification