Signal calibration apparatus in a smart antenna system

• US 20070149251A1
• Filed: 12/26/2006
• Published: 06/28/2007
• Est. Priority Date: 12/26/2005
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Jeon, Min
• Application Number:
  US11/645,402
• Publication Number:
  US 20070149251A1
• Time in Patent Office: Days
• US Class Current: 455/562.100
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices

Abstract

A signal calibration apparatus in a smart antenna system is provided. In the signal calibration apparatus, a beamformer and calibrator sends a calibration signal through each of N transmitters, extracts the calibration signal from a signal received from a calibration receiver, and calibrates a transmission signal in a transmission path corresponding to the transmitter using the extracted calibration signal during a downlink time period. During an uplink time period, the beamformer and calibrator sends a calibration signal through a calibration transmitter, extracts the calibration signal from a signal received from each of N receivers, and calibrates a reception signal in a reception path corresponding to the receiver using the extracted calibration signal during an uplink time period.

Claims

1. A signal calibration apparatus for a Base Station (BS) in a smart antenna system, comprising:

a beamformer and calibrator for generating a calibration signal for each of N transmitters, transmitting the calibration signal through the each transmitter, extracting the calibration signal from a signal received from a calibration receiver co-functioning as a general receiver, and calibrating a transmission signal in a transmission path corresponding to the each transmitter using the extracted calibration signal during a downlink time period, and for generating a calibration signal for each of N receivers, transmitting the calibration signal through a calibration transmitter co-functioning as a general transmitter, extracting the calibration signal from a signal received from each of N receivers, and calibrating a reception signal in a reception path corresponding to the each receiver using the extracted calibration signal during an uplink time period; and

the N transmitters and receivers, each for converting the signal received from the beamformer and calibrator to a Radio Frequency (RF) signal, sending the RF signal to a predetermined array antenna, coupling the calibration signal sent to the array antenna, and transmitting the coupled calibration signal to the calibration receiver during the downlink time period, and modulating the calibration signal received from the calibration receiver to a baseband signal and providing the baseband signal to the beamformer and calibrator during the uplink time period,

wherein the calibration transmitter and receiver is one transmitter and receiver from among the N transmitter and receivers, modulates the calibration signal received from the each of the N transmitters and receivers to a baseband signal and provides the baseband signal to the beamformer and calibrator during the downlink time period, and modulates the calibration signal received from the beamformer and calibrator to an RF signal, divides the RF signal into N signals, and provides the N signals to the N transmitters and receivers during the uplink time period.

2. The signal calibration apparatus of claim 1, wherein each of the N transmitters and receivers comprises:

a Digital UpConverter (DUC) for oversampling the calibration signal received from the beamformer and calibrator during the downlink time period;

a transmission module for modulating the oversampled signal to the RF signal during the downlink time period;

a transceiver control board for sending the RF signal to the array antenna during the downlink time period and sending a signal received from a coupler to a receiving module during the uplink time period;

the coupler for coupling the calibration signal sent to the array antenna and providing the coupled calibration signal to the calibration receiver during the downlink time period, and providing the calibration signal received from the calibration transmitter to the transceiver control board during the uplink time period;

the receiving module for modulating the calibration signal received from the transceiver control board to the baseband signal during the uplink time period; and

a Digital DownConverter (DDC) for providing the baseband signal to the beamformer and calibrator during the uplink time period.

3. The signal calibration apparatus of claim 2, wherein the transmission module comprises:

a Digital-to-Analog Converter (DAC) for converting the oversampled digital signal received from the DUC to an analog signal;

a first amplifier for amplifying the analog signal to a predetermined power level;

a mixer for converting the amplified signal to a predetermined frequency band by means of a local oscillator;

a second amplifier for amplifying the calibration signal received from the mixer to a predetermined power level; and

a High Power Amplifier (HPA) for amplifying the amplified calibration signal to a predetermined power level.

4. The signal calibration apparatus of claim 2, wherein the transceiver control board comprises:

a Time Division Duplex (TDD) switch for switching the calibration signal modulated to the RF signal to a first Band Pass Filter (BPF) during the downlink time period, and switching a calibration signal received from the first BPF to the receiving module during the uplink time period; and

the first BPF for sending a signal falling within a predetermined frequency range in the calibration signal received from the TDD switch to the array antenna during the downlink time period, and outputting a signal falling within a predetermined frequency range in the calibration signal received from the coupler to the TDD switch during the uplink time period.

5. The signal calibration apparatus of claim 2, wherein the receiving module comprises:

a first Low Noise Amplifier (LNA) for amplifying the received calibration signal to a predetermined power level;

a second BPF for outputting only a signal falling within a predetermined frequency band in the amplified signal;

a mixer for converting the filtered signal received from the second BPF to a predetermined frequency band by means of a local oscillator;

a second LNA for amplifying the converted signal to a predetermined power level; and

an Analog-to-Digital Converter (ADC) for converting the amplified analog signal to a digital signal and outputting the digital signal to the DDC.

6. The signal calibration apparatus of claim 2, wherein the calibration transmitter and receiver comprises:

an N;

1 divider for providing the calibration signal received from each of the couplers of the N transmitters and receivers to the receiving module during the downlink time period, and dividing the calibration signal modulated to the RF signal into the N signals and outputting the N signals to the couplers of the N transmitters and receivers during the uplink time period;

the receiving module for converting the signal received from the N;

1 divider to a baseband signal during the downlink time period;

the DDC for providing the modulated baseband signal to the beamformer and calibrator during the downlink time period;

the DUC for oversampling the calibration signal received from the beamformer and calibrator during the uplink time period; and

the transmission module for modulating the oversampled signal to the RF signal during the uplink time period.

7. The signal calibration apparatus of claim 6, further comprising:

a first 2;

1 switch for switching the signal received from the N;

1 divider to a second 2;

1 switch during the downlink time period, and switching a signal received from a third 2;

1 switch to the N;

1 divider during the uplink time period;

the second 2;

1 switch for switching the signal received from the first 2;

1 switch to the receiving module during the downlink time period, and switching a signal received from the transceiver control board to the receiving module during the uplink time period; and

the third 2;

1 switch for switching a signal received from the second amplifier of the transmission module to the HPA of the transmission module during the downlink time period, and switching a signal received from the second amplifier of the transmission module to the first 2;

1 switch during the uplink time period.

8. The signal calibration apparatus of claim 7, wherein the beamformer and calibrator controls the first, second and third 2:

1 switches by a switching control signal during the downlink and uplink time periods.