US 6,633,766 B1 · Frequency selective RF output power calibration using digital and analog power measurements for use in a cellular telecommunications system

Abstract

In the context of a wideband CDMA (WCDMA) type base station (BS) in a cellular telecommunications network, radio frequency (RF) gain is accurately controlled for each of multiple carrier frequency bands without having to disturb the normal operation of the amplifier chain once installed at the BS. The power of a summed or combined digital baseband user signal is determined and integrated over a specific time interval. The digital baseband signal is upconverted and amplified by one or more (e.g., a chain of) RF amplifiers. The power of the transmitted RF signal (downlink signal transmitted by the BS) is detected in a frequency selective manner, and integrated over the same time interval. The difference between the integrated baseband power and the RF transmit power is determined to provide an overall gain for the RF chain for the specific carrier frequency measured. This gain value is compared with a target gain value to determine a gain adjustment or correction factor which is applied in the digital domain prior to digital-to-analog conversion (DAC). Accordingly, gain control for each of a plurality of different carrier frequency bands is substantially continuously performed during normal operation of the BS.

Claims25

Dependent claims

A method of controlling output power of a base station in a wideband code division multiple access (WCDMA) cellular telecommunications system, the method comprising the steps of:

combining a plurality of modulated channels into a combined digital baseband signal for a first of a plurality of carrier frequencies transmitted by the base station in the WCDMA cellular telecommunications system;
determining, in a digital domain, a power of the combined digital baseband signal for the first carrier frequency;
converting the digital baseband signal to an analog signal;
determining an RF power of the analog signal for the first carrier frequency, while excluding at least a second of the carrier frequencies transmitted by the base station;
calculating a gain value proximate an actual gain utilizing at least the determined power of the combined digital baseband signal and the determined RF power of the analog signal;
determining a gain adjustment factor or value utilizing at least the calculated gain value and a target gain value;
and
applying the gain adjustment factor or value to a digital baseband signal for the first carrier frequency in order to adjust the gain of the base station toward the target gain value.

5 more elements

A method of controlling output power of a transmitter, the method comprising the steps of:

combining a plurality of modulated channels into a combined digital baseband signal for a first carrier frequency;
determining, in a digital domain, a power of the combined digital baseband signal;
converting the digital baseband signal to an analog signal;
determining power of the analog signal for the first carrier frequency;
calculating a gain value utilizing at least the determined power of the combined digital baseband signal and the determined power of the analog signal;
determining a gain adjustment factor or value utilizing at least the calculated gain value and a target gain;
and
applying the gain adjustment factor or value to a digital baseband signal for the first carrier frequency in the transmitter in order to adjust the gain of the transmitter toward the target gain.

5 more elements

A base station in a wideband code division multiple access (WCDMA) cellular telecommunications network, the base station comprising:

a combiner for combining a plurality of modulated channels into a combined digital baseband signal for a first of a plurality of carrier frequencies to be transmitted by the base station to at least one mobile station located in a cell of the base station;
a first baseband power sensor for determining, in a digital domain, a power of the combined digital baseband signal for the first carrier frequency;
a digital to analog converter for converting the digital baseband signal to an analog signal;
an RF power sensor for determining power of the analog signal for the first carrier frequency;
gain calculating circuitry for calculating a gain adjustment factor or value based at least upon a target gain, the determined power of the analog signal, and the determined power of the digital baseband signal;
and
gain adjustment circuitry for applying the gain adjustment factor or value to a digital baseband signal for the first carrier frequency in order to adjust the gain of the base station toward the target gain.

4 more elements

Dependencies are inferred from the claim text.

Frequency selective RF output power calibration using digital and analog power measurements for use in a cellular telecommunications system

Life of this patent

Frequency selective RF output power calibration using digital and analog power measurements for use in a cellular telecommunications system

Life of this patent

Abstract

Claims25