Radio unit with internal parallel antenna calibration

Patent metadata

Field	Value
Publication number	US-10122476-B2
Application number	US-201315034199-A
Country	US
Kind code	B2
Filing date	Nov 8, 2013
Priority date	Nov 8, 2013
Publication date	Nov 6, 2018
Grant date	Nov 6, 2018

Abstract

The present disclosure provides a radio unit with internal parallel antenna calibration. The radio unit comprises an antenna calibrator, a plurality of transmission signal processing sections, a plurality of power amplifiers, a plurality of bandpass filters, a plurality of couplers, a plurality of reception signal processing sections and a first combiner. The antenna calibrator is configured to generate a plurality of individually identifiable reference signals used for transmission calibration. The transmission signal processing sections are configured to modulate the signals in parallel. The power amplifiers are configured to amplify the modulated signals to predetermined power levels in parallel. The bandpass filters are configured to apply bandpass filtering operations to the modulated signals in parallel. The couplers are configured to couple the filtered signals to a first combiner, which combines the filtered signals. One of the reception signal processing sections is configured to identify and demodulate each of the filtered signals constituting the combined signals. The antenna calibrator is further configured to compute transmission calibration vectors by comparing the demodulated signals with the reference signals.

First claim

What is claimed is:

1. A radio unit, comprising:
an antenna calibrator configured to generate a plurality of individually identifiable reference signals used for transmission calibration;
a plurality of transmission signal processing sections configured to modulate the individually identifiable reference signals in parallel;
a plurality of power amplifiers configured to amplify the modulated signals to predetermined power levels in parallel;
a plurality of bandpass filters configured to apply bandpass filtering operations to the amplified signals in parallel;
a plurality of couplers configured to couple the filtered signals to a first combiner which combines the filtered signals; and
a plurality of reception signal processing sections, one of which is configured to identify and demodulate each of the filtered signals constituting the combined signals;
wherein the antenna calibrator is further configured to compute transmission calibration vectors by comparing the demodulated signals with the individually identifiable reference signals;
wherein the radio unit further comprises a Voltage Standing Wave Ratio measurement unit, a first plurality of switches connected between the first combiner and the couplers, a second combiner and a second plurality of switches connected between the second combiner and the couplers;
wherein forward powers for respective antenna branches are respectively sent back to the first plurality of switches, and reflected powers for respective antenna branches are respectively sent back to the second plurality of switches; and
in a case where VSWR measurement is performed for one antenna branch, only a corresponding one of the first switches and a corresponding one of the second switches are closed, so that a corresponding one of the forward powers is selected by the first combiner and a corresponding one of the reflected powers is selected by the second combiner; and
the VSWR measurement unit is configured to compute the VSWR for the antenna branch based on the selected forward power and reflected power.

2. The radio unit of claim 1 , further comprising a plurality of low noise amplifiers, and wherein
the antenna calibrator is further configured to generate a reference signal used for reception calibration;
one of the plurality of transmission signal processing sections is further configured to modulate the reference signal;
the first combiner is further configured to split the modulated signal;
the plurality of couplers are further configured to couple the split signals to the plurality of bandpass filters;
the plurality of bandpass filters are further configured to apply bandpass filtering operations to the split signals in parallel;
the plurality of low noise amplifiers are configured to amplify the filtered signals to predetermined power levels in parallel;
the plurality of reception signal processing sections are further configured to demodulate the amplified signals in parallel; and
the calibrator is further configured to compute reception calibration vectors by comparing the demodulated signals with the reference signal.

3. The radio unit of claim 2 , further comprising three switches, wherein
a first one of the three switches is configured to direct the modulated signal from the one of the plurality of transmission signal processing sections to its respective power amplifier in the case of internal transmission calibration, and to direct the modulated signal from the one of the plurality of transmission signal processing sections to the first combiner via a third one of the three switches in the case of internal reception calibration; and
a second one of the three switches is configured to direct the filtered signal to the one of the plurality of reception signal processing sections from its respective low noise amplifier in the case of internal reception calibration, and to direct the combined signal to the one of the plurality of reception signal processing sections from the first combiner via the third one of the three switches in the case of internal transmission calibration.

4. The radio unit of claim 1 , further comprising
a fourth switch configured to direct the combined signal from the first combiner to the one of the reception signal processing sections or direct the modulated signal from the one of the transmission signal processing sections to the first combiner in the case of internal antenna calibration, and to direct the selected forward power from the first combiner to the VSWR measurement unit in the case of VSWR measurement.

5. The radio unit of claim 1 , further comprising an external calibration port for external antenna calibration.

6. The radio unit of claim 5 , further comprising
a fifth switch configured to direct the combined signal from the first combiner to the one of the reception signal processing sections or direct the modulated signal from the one of the transmission signal processing sections to the first combiner in the case of internal antenna calibration, and to direct a combined signal from the external calibration port to the one of the reception signal processing sections or direct the modulated signal from the one of the transmission signal processing sections to the external calibration port in the case of external antenna calibration.

7. The radio unit of claim 1 , wherein the radio unit is a Remote Radio Unit.

8. The radio unit of claim 1 , wherein
the antenna calibrator of the radio unit is implemented in a BaseB and Unit and other components of the radio unit than the antenna calibrator are implemented in an RRU, and
the RRU comprises a Common Public Radio Interface, via which the RRU communicates with the BBU.

9. The radio unit of claim 1 , wherein there are four or eight transmission and/or reception paths within the radio unit.

Assignees

• Ericsson Telefon Ab L M

Inventors

• Sun Xuejun
• Liu Chang

Classifications

• H04B17/221

  of receiver antennas, e.g. as to amplitude or phase · CPC title

• H04B7/04

  using two or more spaced independent antennas · CPC title

• H04B17/21

  for calibration; for correcting measurements · CPC title

• H04B17/0085

  using test signal generators · CPC title

• H04B17/102

  Power radiated at antenna · CPC title