Self-calibration of antenna array system

Patent metadata

Field	Value
Publication number	US-11158940-B2
Application number	US-201716486416-A
Country	US
Kind code	B2
Filing date	Mar 13, 2017
Priority date	Mar 13, 2017
Publication date	Oct 26, 2021
Grant date	Oct 26, 2021

Abstract

Systems and methods relating to self-calibration of an antenna array of a transceiver are disclosed. In some embodiments, a method of operation of a transceiver to perform self-calibration for transmit (Tx) antenna elements and receive (Rx) antenna elements in an antenna array comprises performing gain measurements and phase measurements for pairs of Tx and Rx antenna elements in the antenna array. The method further comprises processing the gain measurements and the phase measurements based on combinations of Tx and Rx antenna elements having symmetrical coupling properties to obtain gain and phase calibration values for the plurality of Tx antenna elements and the plurality of Rx antenna elements in the antenna array and applying the gain and phase calibration values at the transceiver. In this manner, self-calibration can be performed at the transceiver dynamically with low complexity.

First claim

The invention claimed is:

1. A method of operation of a transceiver to perform self-calibration for a plurality of transmit, Tx, antenna elements and a plurality of receive, Rx, antenna elements in an antenna array, comprising:
performing gain measurements, G MTx i Rx j , and phase measurements, ϕ MTx i Rx j , for pairs of Tx and Rx antenna elements in the antenna array, where gain measurement G MTx i Rx j and phase measurement ϕ MTx i Rx j are measured gain and phase at an output of a receiver compared to the input of a transmitter, when the receiver is coupled to a j-th Rx antenna element during reception of a signal transmitted by a transmitter coupled to an i-th Tx antenna element;
processing the gain measurements, G MTx i Rx j , and the phase measurements, ϕ MTx i Rx j , based on combinations of Tx and Rx antenna elements having symmetrical coupling properties to obtain gain and phase calibration values for the plurality of Tx antenna elements and the plurality of Rx antenna elements in the antenna array; and
applying the gain and phase calibration values at the transceiver;
wherein processing the gain measurements, G MTx i Rx j , and the phase measurements, ϕ MTx i Rx j , comprises:
selecting a pair of Tx antenna elements, Tx i and Tx k , where i≠k;
determining a first pair of Rx antenna elements, Rx n and Rx m , having symmetrical coupling properties with respect to the pair of Tx antenna elements, Tx i and Tx k ;
computing at least one relative gain value and at least one relative phase value for the Tx antenna element Tx i relative to the Tx antenna element Tx k based on at least two of:
the gain measurement, G MTx i Rx n , and the phase measurement, ϕ MTx i Rx n , for the pair of Tx and Rx antenna elements Tx i and Rx n ;
the gain measurement, G MTx i Rx m , and the phase measurement, ϕ MTx i Rx m , for the pair of Tx and Rx antenna elements Tx i and Rx m ;
the gain measurement, G MTx k Rx n , and the phase measurement, ϕ MTx k Rx n , for the pair of Tx and Rx antenna elements Tx k and Rx n ; and
the gain measurement, G MTx k Rx m , and the phase measurement, ϕ MTx k Rx m , for the pair of Tx and Rx antenna elements Tx k and Rx m ;

repeating the steps of determining and computing for at least one second pair of Rx antenna elements, Rx n , and Rx m , having symmetrical coupling properties with respect to the pair of Tx antenna elements, Tx i and Tx k ;
averaging the relative gain values and the relative phase values for the Tx antenna element Tx i relative to the Tx antenna element Tx k across the first pair of Rx antenna elements and the at least one second pair of Rx antenna elements to thereby provide an average relative gain value and an average relative phase value for the Tx antenna element Tx i relative to the Tx antenna element Tx k ;
repeating the steps of selecting, determining, computing, repeating, and averaging for at least one second pair of Tx antenna elements; and
normalizing the average relative gain values and the average relative phase values relative to a defined reference Tx antenna element to thereby provide gain and phase calibration values for the plurality of Tx antenna elements.

2. The method of claim 1 wherein:
a mutual coupling between the Tx antenna element Tx i and the Rx antenna element Rx n is approximately the same as a mutual coupling between the Tx antenna element Tx k and the Rx antenna element Rx n ;
a mutual coupling between the Tx antenna element Tx i and the Rx antenna element Rx m is approximately the same as a mutual coupling between the Tx antenna element Tx k and the Rx antenna element Rx m ; and
the at least one relative gain value and the at least one relative phase value for the Tx antenna element Tx i relative to the Tx antenna element Tx k comprises a relative gain value defined as:

Δ
⁢

⁢

G

T
⁢

⁢

x
i

⁢

Tx
k

⁡

(
1
)

=

(

G

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x
i

⁢

Rx
n

-

G

MT
⁢

⁢

x
k

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Rx
n

)

+

(

G

MT
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x
i

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Rx
m

-

G

MT
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x
k

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Rx
m

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2

and a relative phase value defined as:

Δ
⁢

Assignees

• Ericsson Telefon Ab L M

Inventors

• Rafique Raihan
• Mannerstråle Jacob

Classifications

• H04B17/221

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

• H04B17/14

  of the whole transmission and reception path, e.g. self-test loop-back · CPC title

• H04B17/13

  of power amplifiers, e.g. gain or non-linearity · CPC title

• H01Q3/267 Primary

  Phased-array testing or checking devices · CPC title

• H01Q21/06

  Arrays of individually energised antenna units similarly polarised and spaced apart · CPC title