Apparatus for adaptive forward power control for spread-spectrum communications
First Claim
1. An improvement apparatus for adaptive forward control of power (APC) from a base station (BS) to a subscriber unit (SU), comprising:
- said base station for sending to said subscriber unit, using spread-spectrum modulation, a BS-spreading code on a forward channel;
said subscriber unit for despreading the BS-.spreading code on the forward channel as a despread signal, for determining a first power level Pd from the despread signal, whereby the first power level Pd includes power of the despread signal plus noise, for determining a second power level PN, whereby the second power level includes the power of despread signal minus 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 Pr 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 base station; and
said base station for receiving the APC bit, and, in response to the APC bit, for adjusting transmitter power to the subscriber unit.
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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 apparatus for adaptive forward power control (APC) from a base station (BS) to a subscriber unit (SU), includes 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 Pd which includes power of the despread signal plus noise and a second power level PN, which includes despread-noise power. The subscriber unit 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 Pr and an automatic gain control (AGC) set point Po. The subscriber unit 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 base station. In response to the APC bit, the base station adjusts transmitter power to the subscriber unit.
169 Citations
12 Claims
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1. An improvement apparatus for adaptive forward control of power (APC) from a base station (BS) to a subscriber unit (SU), comprising:
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said base station for sending to said subscriber unit, using spread-spectrum modulation, a BS-spreading code on a forward channel;
said subscriber unit for despreading the BS-.spreading code on the forward channel as a despread signal, for determining a first power level Pd from the despread signal, whereby the first power level Pd includes power of the despread signal plus noise, for determining a second power level PN, whereby the second power level includes the power of despread signal minus 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 Pr 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 base station; and
said base station for receiving the APC bit, and, in response to the APC bit, for adjusting transmitter power to the subscriber unit. - View Dependent Claims (2, 3)
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4. An improvement apparatus for adaptive forward control of power (APC) from a base station (BS) to a subscriber unit (SU), comprising:
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base means for transmitting, using spread-spectrum modulation, a BS-spreading code on a forward channel;
subscriber means for despreading the B S-spreading code on the forward channel as a despread signal, for determining a first power level Pd from the despread signal, whereby the first power level Pd includes power of the despreacd signal plus noise, for determining a second power level PN, whereby the second power level includes the power of the despread signal minus 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 Pr 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 a, and a second weight a2, with the first weight a, 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 base means; and
said base means for receiving the APC bit, and, in response to the APC bit, for adjusting transmitter power to the subscriber means. - View Dependent Claims (5, 6)
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7. An improvement apparatus for adaptive forward control of power (APC) from a base station (BS) to a subscriber unit (SU), comprising:
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said base station for sending to said subscriber unit, using spread-spectrum modulation, a BS-spreading code on a forward channel;
said subscriber unit for despreading the BS-spreading code on the forward channel as a despread signal, for determining a first power level Pd from the despread signal, whereby the first power level Pd includes 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 signal minus 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 Pr 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 having at least two bits, and for transmitting the APC word to the base station; and
said base station for receiving the APC word, and, in response to the APC word, for adjusting transmitter power to the subscriber unit. - View Dependent Claims (8, 9)
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10. An improvement apparatus for adaptive forward control of power (APC) from a base station (BS) to a subscriber unit (SU), comprising:
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base means for transmitting, using spread-spectrum modulation, a BS-spreading code on a forward channel;
subscriber means for despreading the BS-spreading code on the forward channel as a despread signal, for determining a first power level Pd from the despread signal, whereby the first power level Pd includes 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 signal minus 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 Pr 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 base means; and
said base means for receiving the APC word, and, in response to the APC word, for adjusting transmitter power to the subscriber means. - View Dependent Claims (11, 12)
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Specification