Transceiver using hybrid beamforming and performing an antenna calibration method

• US 10,707,974 B1
• Filed: 10/14/2019
• Issued: 07/07/2020
• Est. Priority Date: 10/14/2019
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Ho, Jan-Shin, Fang, Shih-Hao, Hsu, Jen-Yuan, Chen, Jia-Ming
• Primary Examiner(s): Nguyen, Lee
• Application Number:
  US16/600,579
• Time in Patent Office: 267 Days
• Field of Search: 4551143, 4555621
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H04B 17/12 of transmit antennas, e.g. of the amplitude or phase
• CPC Class Codes: H04B 17/14 of the whole transmission and reception path, e.g. self-test loop-back
• CPC Class Codes: H04B 17/19 Self-testing arrangements
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04W 72/29 between an access point and the access point controlling device

Abstract

The disclosure provides a transceiver of a communication system using hybrid beamforming and performing an antenna calibration method. In an exemplary embodiment in accordance with the disclosure, the transceiver may generate a plurality of scrambling sequences. The transceiver may comprise a plurality of coupling circuits to receive a feedback signal. The transceiver may use the plurality of scrambling sequences to recover the transmit signals output by the antenna elements from the feedback signal. Thus, the transmitter may perform antenna calibration for each antenna element.

Claims

1. A transceiver of a communication system using hybrid beamforming, configured to perform an antenna calibration method, the transceiver comprising:

a processor, outputting a plurality of digital precoded signals;

a plurality of digital-to-analog converters (DAC), coupled to the processor, receiving the plurality of digital precoded signals and outputting a plurality of analog baseband signals;

a plurality of radio frequency (RF) chains, coupled to the plurality of DACs, receiving the plurality of analog baseband signals, performing frequency upconversion, and outputting a plurality of RF signals;

a plurality of phase shifters, receiving the plurality of RF signals from the plurality of RF chains, performing phase shifting on the plurality of RF signals according to a plurality of orthogonal scrambling sequences, and outputting a plurality of shifted RF signals;

a plurality of power amplifiers, receiving the plurality of shifted RF signals from the plurality of phase shifters, amplifying the plurality of shifted RF signals, and outputting a plurality of transmit signals;

a plurality of antenna elements, coupled to the plurality of power amplifiers, receiving the plurality of transmit signals, and transmitting the plurality of transmit signals;

a plurality of coupling circuits, coupled to the plurality of antenna elements, receiving the plurality of transmit signals, combining the plurality of transmit signals, and outputting a feedback signal;

a feedback network, coupled to the plurality of coupling circuits, receiving the feedback signal; and

an observation receiver (ORX), coupled to the feedback network, receiving the feedback signal, performing frequency downconversion on the feedback signal, and converting the feedback signal to a digital feedback signal,

wherein the processor is configured to execute a plurality of modules, the plurality of modules comprising;

a digital precoder, performing precoding on a plurality of digital signals, and outputting the plurality of digital precoded signals;

a plurality of calibration compensation modules, performing calibration compensation on the plurality of digital precoded signals to compensate excesses of phase, gain and delay in the plurality of transmit signals, the excesses of phase, gain and delay are caused by the plurality of DACs, the plurality of RF chains, the plurality of phase shifters and the plurality of power amplifiers; and

a calibrator, receiving the digital feedback signal, sending a plurality of calibration sequences to the plurality of calibration compensation modules and sending a plurality of orthogonal scrambling sequences to the plurality of phase shifters, wherein the plurality of phase shifters perform phase shifting on the plurality of RF signals according to the plurality of orthogonal scrambling sequences,

wherein when the processor outputs the plurality of calibration sequences to the plurality of DACs, the calibrator receives the digital feedback signal, the calibrator compares the digital feedback signal with the plurality of calibration sequences and the plurality of orthogonal scrambling sequences to determine the excesses of phase, gain and delay and adjust the calibration compensation performed by the plurality of calibration compensation modules.

2. The transceiver of claim 1, wherein the calibrator is a baseband unit (BBU) or a remote radio head (RRH).

3. The transceiver of claim 1, wherein the plurality of scrambling sequences is a plurality of Hadamard sequences or Walsh sequences.

4. The transceiver of claim 1, wherein an external baseband processing unit is coupled to the transceiver, and is configured to generate the plurality of calibration sequences.

5. The transceiver of claim 4, wherein the external baseband processing unit is further configured to estimate the excesses of phase, gain and delay.

6. The transceiver of claim 1, wherein an external baseband processing unit is coupled to the transceiver, and is configured to estimate the excesses of phase, gain and delay.

7. The transceiver of claim 1, wherein a common wideband channel response is an excess of phase, gain and delay caused by the plurality of DACs and RF chains, and the calibrator adjusts the calibration compensation to compensate the common wideband channel response.

8. The transceiver of claim 1, wherein the transceiver further comprises:

a plurality of tunable analog filters, receiving the plurality of RF signals from the plurality of RF chains, and coupled to the plurality of phase shifters,

wherein a common wideband channel response is an excess of phase, gain and delay caused by the plurality of DACs and RF chains, and the calibrator adjusts the calibration compensation of the plurality of calibration compensation modules to compensate the common wideband channel response,

wherein the calibrator adjusts the plurality of tunable analog filters to provide calibration compensation for excess of phase, gain and delay caused by the plurality of phase shifters and the plurality of power amplifiers.