KR102449587B1 - Apparatus and method for calibrating phased array antenna - Google Patents

Abstract

The present disclosure relates to a ^5th generation ( ^5G ) or pre-5G communication system for supporting a higher data rate after a 4th generation (4G) communication system such as Long Term Evolution (LTE). According to various embodiments of the present disclosure, in a method for calibrating a phased array antenna, by setting phase codes in a target RF (radio frequency) chain, at least one calibration code of the target RF chain a process of estimating a candidate code of , the intensity of a first combined signal estimated for the phase codes under a condition that the at least one candidate code corresponds to a reference phase, and a second combination measured with respect to the phase codes A process of determining an error between the signal strength, a process of determining the calibration code based on the error, and a process of calibrating the target RF chain by setting the calibration code in the target RF chain include The first combined signal and the second combined signal include a combination of signals related to the target RF chain and the reference RF chain. The apparatus and method according to various embodiments of the present disclosure enable the calibration code to be quickly and accurately estimated by estimating the calibration code using some phase codes and considering the error of the estimated candidate code.

Description

Apparatus and method for calibrating a phased array antenna

BACKGROUND This disclosure relates generally to calibration, and more particularly to an apparatus and method for calibrating a phased array antenna.

Efforts are being made to develop an improved ^5th generation ( ^5G ) communication system or a pre-5G communication system in order to meet the increasing demand for wireless data traffic after commercialization of the 4G (4th generation) communication system. For this reason, the 5G communication system or the pre-5G communication system is called a 4G network after (Beyond 4G Network) communication system or an LTE (Long Term Evolution) system after (Post LTE) system.

In order to achieve a high data rate, the 5G communication system is being considered for implementation in a very high frequency (mmWave) band (eg, such as a 60 gigabyte (60 GHz) band). In order to alleviate the path loss of radio waves and increase the propagation distance of radio waves in the ultra-high frequency band, in the 5G communication system, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) are used. ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed.

In addition, for network improvement of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud radio access network, cloud RAN), an ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and reception interference cancellation (interference cancellation) Technology development is underway.

In addition, in the 5G system, Hybrid Frequency Shift Keying and Quadrature Amplitude Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), which are advanced coding modulation (Advanced Coding Modulation, ACM) methods, and Filter Bank Multi Carrier (FBMC), an advanced access technology, ), Non Orthogonal Multiple Access (NOMA), and Sparse Code Multiple Access (SCMA) are being developed.

As described above, in order to perform communication in a very high frequency band such as a millimeter wave band, beamforming of a transmission signal or a reception signal is required. For example, for beamforming, a phased array antenna may be used. A phased array antenna includes a plurality of antenna elements whose phase is adjustable. When the phase of each antenna element is properly controlled, a signal can be transmitted in a specific direction, or a beam of a specific direction can be formed.

In calibration of the phased array antenna, when signals of the same phase are input to the antenna elements included in the phased array antenna, a phase code is applied to each antenna element so that signals passing through the antenna elements all have the same phase. ) can be defined as setting Once the phased array antenna is calibrated, by setting each antenna element a phase code corresponding to a specific direction, the phased array antenna can form a beam in a specific direction. Therefore, in order to efficiently perform beamforming using the phased array antenna, proper calibration of the phased array antenna is required.

Based on the above discussion, the present disclosure provides an apparatus and method for calibrating a phased array antenna.

In addition, the present disclosure provides an apparatus for estimating a candidate code for a calibration code of a target RF chain using some phase codes among available phase codes that can be set in a target RF (radio frequency) chain and methods.

In addition, the present disclosure provides an apparatus and method for determining a calibration code in consideration of an error with respect to estimated candidate codes.

Also, the present disclosure provides an apparatus and method for determining the relevance of measurement values for estimating a calibration code.

In addition, the present disclosure provides an apparatus and method for performing calibration according to a type of calibration.

In addition, the present disclosure provides an apparatus and method for transmitting a signal or forming a beam in a desired direction using a phased array antenna after calibration.

According to various embodiments of the present disclosure, in a method for calibrating a phased array antenna, by setting phase codes in a target RF (radio frequency) chain, at least one calibration code of the target RF chain a process of estimating a candidate code of , the intensity of a first combined signal estimated for the phase codes under a condition that the at least one candidate code corresponds to a reference phase, and a second combination measured with respect to the phase codes A process of determining an error between the signal strength, a process of determining the calibration code based on the error, and a process of calibrating the target RF chain by setting the calibration code in the target RF chain include The first combined signal and the second combined signal include a combination of signals related to the target RF chain and the reference RF chain.

According to various embodiments of the present disclosure, an apparatus for calibrating a phased array antenna sets phase codes in a target RF chain to estimate at least one candidate code for a calibration code of the target RF chain, and the at least one Determine an error between the intensity of the first combined signal estimated for the phase codes and the intensity of the second combined signal measured with respect to the phase codes under the condition that the candidate code of ? corresponds to the reference phase, and based on the calibration code, and sets the calibration code in the target RF chain to calibrate the target RF chain. The first combined signal and the second combined signal include a combination of signals related to the target RF chain and the reference RF chain.

The apparatus and method according to various embodiments of the present disclosure enable the calibration code to be quickly and accurately estimated by estimating the calibration code using some phase codes and considering the error of the estimated candidate code.

The apparatus and method according to various embodiments of the present disclosure may detect an error occurring in a calibration process early by determining the relevance of measurement values for estimating a calibration code, and prevent an incorrect calibration code from being estimated can be prevented

Effects obtainable in the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those of ordinary skill in the art to which the present disclosure belongs from the description below. will be.

1 illustrates a phased array antenna according to various embodiments of the present disclosure.
2A and 2B illustrate a first configuration of a calibration apparatus according to various embodiments of the present disclosure.
3 is a flowchart illustrating a calibration apparatus according to various embodiments of the present disclosure.
4 is a flowchart for determining a candidate code for a calibration code according to various embodiments of the present disclosure.
5A and 5B illustrate graphs for representing estimation of a candidate code according to various embodiments of the present disclosure;
6 is a flowchart for determining an error for a candidate code according to various embodiments of the present disclosure.
7A and 7B are graphs illustrating errors for estimated candidate codes according to various embodiments of the present disclosure;
8 illustrates examples of calibration results according to various embodiments of the present disclosure.
9 is a flowchart illustrating relevance of an estimated test signal strength according to various embodiments of the present disclosure;
10A and 10B illustrate other examples of calibration results according to various embodiments of the present disclosure.
11 is a flowchart for confirming validity of an estimated candidate code according to various embodiments of the present disclosure.
12 is a diagram illustrating a relationship between validity of an estimated strength of a test signal and validity of an estimated candidate code according to various embodiments of the present disclosure.
13 is a flowchart for determining the validity of the measured strength of a reference signal according to various embodiments of the present disclosure.
14 is a flowchart illustrating overall operations of a calibration apparatus according to various embodiments of the present disclosure.
15 is a flowchart for determining a calibration code in consideration of an additional candidate code according to various embodiments of the present disclosure.
16 is a graph illustrating a function of a combined signal strength for an additional candidate code according to various embodiments of the present disclosure.
17 illustrates phase codes set in RF chains as a result of calibration according to various embodiments of the present disclosure.
18 illustrates a type of calibration according to various embodiments of the present disclosure.
19A and 19B illustrate signal exchange between communication devices for online calibration according to various embodiments of the present disclosure.
20 is a flowchart for online calibration according to various embodiments of the present disclosure.
21 is a flowchart for forming a beam in a specific direction after calibration according to various embodiments of the present disclosure;

Terms used in the present disclosure are used only to describe specific embodiments, and may not be intended to limit the scope of other embodiments. The singular expression may include the plural expression unless the context clearly dictates otherwise. Terms used herein, including technical or scientific terms, may have the same meanings as commonly understood by one of ordinary skill in the art described in the present disclosure. Among the terms used in the present disclosure, terms defined in a general dictionary may be interpreted with the same or similar meaning as the meaning in the context of the related art, and unless explicitly defined in the present disclosure, ideal or excessively formal meanings is not interpreted as In some cases, even terms defined in the present disclosure cannot be construed to exclude embodiments of the present disclosure.

In various embodiments of the present disclosure described below, a hardware access method will be described as an example. However, since various embodiments of the present disclosure include technology using both hardware and software, various embodiments of the present disclosure do not exclude a software-based approach.

Hereinafter, the present disclosure relates to an apparatus and method for calibrating a phased array antenna in a wireless communication system. Specifically, the present disclosure provides a candidate code for a calibration code of each RF chain by using some of the available phase codes that can be set in each RF (radio frequency) chain of a phased array antenna quickly. A technique for estimating and accurately estimating a calibration code in consideration of an error with respect to a candidate code will be described.

Terms that refer to signals, terms that refer to network entities, and terms that refer to components of devices used in the following description are exemplified for convenience of description. Accordingly, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

1 illustrates a phased array antenna 100 according to various embodiments of the present disclosure. Referring to FIG. 1 , a phased array antenna 100 includes a plurality of RF chains 110-1 to 110-N. Hereinafter, for convenience of description, the configurations and functions of the RF chain 110-1 are described, but this is for convenience of description, and other RF chains (eg, RF chains 110-2 to 110-N) The components may also perform the same or similar functions as those of the RF chain 110-1.

The mixer 110-1-1 may convert a center frequency of an input signal and output a signal having the converted center frequency. For example, the mixer 110-1-1 may convert an intermediate frequency (IF) signal into an RF signal or convert an RF signal into an IF signal. Here, the frequency of the RF signal is expressed as the sum of the frequency of the IF signal and the frequency of the local oscillator (LO) signal. Conversely, the frequency of the IF signal is expressed as the result of subtracting the frequency of the LO signal from the frequency of the RF signal. can be To this end, the mixer 110-1-1 may be connected to the LO.

The phase shifter 110-1-3 may convert a phase of an input signal and output a signal having the converted phase. For example, the phase shifters 110-1-3 may lag the phase of the input signal or advance the phase of the input signal. One phase code among a plurality of phase codes may be set in the phase converter 110-1-3. Each of the plurality of phase codes may correspond to one of the phases in the range of 0 degrees to 360 degrees, and each of the different phase codes may correspond to each of the different phases. For example, when the available phase codes that can be set in the phase converter 110-1-3 are 0 to 15 (ie, 16) in decimal, the phase corresponding to the phase code n is 2π/16×n can be The above-described number of phase codes and a method of correspondence between phase codes and phases are exemplary, and various modifications are possible. When a specific phase code is set in the phase shifter 110-1-3, the phase shifter 110-1-3 may change the phase of the signal input to the phase shifter 110-1-3 to a phase corresponding to the set phase code, A phase signal can be output. The phase code may be set in the phase shifter 110-1-3 by a control signal for the phase shifter 110-1-3, and the phase code set in the phase shifter 110-1-3 is the phase code for the phase shifter 110-1-3. It can be changed to another phase code by a control signal. According to various embodiments of the present disclosure, the phase code may also be referred to as a phase value or a phase shifter code (PS code). Also, setting the phase code in the phase converter (eg, phase converter 110-1-3) may be understood as setting the phase code in the RF chain (eg, RF chain 110-1) including the phase converter.

The amplifier 110-1-5 may amplify the input signal. The amplifier 110-1-5 may provide the amplified signal to a radiator 110-1-7. The radiation element 110-1-7 may convert an input electrical signal into an electromagnetic wave and radiate the electromagnetic wave into a free space.

Signal 120-1 is transmitted from RF chain 110-1 through mixer 110-1-1, phase converter 110-1-3, amplifier 110-1-5 and radiating element 110-1-7, or radiating element It can be received by the RF chain 110-1 via 110-1-7, amplifier 110-1-5, phase converter 110-1-3 and mixer 110-1-1. Similarly, signal 120-2 may be transmitted from or received by RF chain 110-2, and signal 120-N may be transmitted from or by RF chain 110-N. can be received.

If the phases of the signals 120-1 to 120-N simultaneously transmitted or received by the plurality of RF chains 110-1 to 110-N are the same, the signals 120-1 to 120-N form a plane wave as a whole and can propagate in a specific direction. Signals 120-1 to 120-N propagated in a specific direction may form a beam (eg, beam 130) in a specific direction. When the phase codes are set in the RF chains 110-1 to 110-N so that the phases of the signals 120-1 to 120-N are the same, the RF chains 110-1 to 110- to change the direction of the beam to a specific direction Phase codes to be set to N may be uniquely determined based on a corresponding direction. Accordingly, once the phase codes are set in the RF chains 110-1 to 110-N so that the phases of the signals 120-1 to 120-N are the same, the communication device including the phased array antenna 100 is configured to correspond to the desired beam direction. Phase codes may be set in the RF chains 110-1 to 110-N, and a beam in a desired direction may be formed through the phased array antenna 100 or the beam may be steered.

According to various embodiments of the present disclosure, in the calibration of the phased array antenna, when signals of the same phase are input to RF chains (eg, RF chains 110-1 to 110-N) included in the phased array antenna, the RF chain It means setting the phase codes in the RF chains so that the signals passing through them all have the same phase. Calibration may be performed for each of the RF chains 110-1 to 110-N. For example, when calibration is performed on the RF chain 110-1, the phase code may be set in the RF chain 110-1 so that the phase of the signal 120-1 is the same as the phase of the signal related to the reference RF chain. Here, the reference RF chain means an RF chain that maintains a phase code for calibration of at least one other RF chain. The reference RF chain may be one of a plurality of RF chains 110-1 to 110-N. For example, when the reference RF chain is 110-1, calibration may be performed on the remaining RF chains 110-2 to 110-N. In this case, the remaining RF chains 110-2 to 110-N on which calibration is to be performed may be referred to as a 'calibration target RF chain' or simply a 'target RF chain'.

When calibration has been performed on an RF chain, that RF chain can serve as a reference RF chain for calibration of other RF chains. In other words, the reference RF chain may be changed while calibrating the plurality of RF chains. For example, when the RF chain 110-1 is used as the reference RF chain for the calibration of the RF chain 110-2, the RF chain 110-2 can be used as the reference RF chain for the calibration of the RF chain 110-3.

Calibration of each of the plurality of RF chains 110 - 1 to 110 -N included in the phased array antenna 100 may be performed by a calibration apparatus. In other words, the calibration apparatus may calibrate each of the plurality of RF chains 110 - 1 to 110 -N included in the phased array antenna 100 . According to various embodiments of the present disclosure, calibrating each of the plurality of RF chains 110-1 to 110-N included in the phased array antenna 100 may be understood as calibrating the phased array antenna 100, and the calibration is performed. The to-be-phased-array antenna may be referred to as a 'target phased-array antenna'.

The configuration of the calibration apparatus for calibrating the phased array antenna 100 will be described in more detail with reference to FIGS. 2A and 2B .

2A illustrates a first configuration of a calibration apparatus 200 according to various embodiments of the present disclosure. Terms such as '~ unit' and '~ group' used below mean a unit for processing at least one function or operation, which may be implemented as hardware or software, or a combination of hardware and software.

Referring to FIG. 2A , the calibration device 200 may be a measuring instrument for calibrating the phased array antenna 100 . In this case, the calibration apparatus 200 may include a controller 210, a transceiver 220, and a reference antenna 230. In FIG. 2A , it is assumed that the calibration apparatus 200 calibrates the phased array antenna 100 for convenience of description, but this is exemplary, and the calibration apparatus 200 may calibrate any phased array antenna.

The controller 210 controls overall operations of the calibration apparatus 200 . For example, the controller 210 may control the transceiver 220 to generate a calibration signal. Also, the controller 210 may control the transceiver 220 to transmit or receive a signal through the reference antenna 230 . The controller 210 may include at least one processor or microprocessor, or may be a part of the processor, in order to perform the above-described control operation.

According to various embodiments, the controller 210 may set a phase code in each of the RF chains and may change the set phase code. To this end, the controller 210 may transmit a control signal for setting or changing the phase code to each of the RF chains. Furthermore, the controller 210 may control an on/off state of each of the RF chains. In other words, the controller 210 may turn on or off each of the RF chains. To this end, the controller 210 may block or maintain a supply voltage of each RF chain. Also, the controller 210 may transmit a control signal (eg, an enable signal) for controlling an on/off state to each of the RF chains.

According to various embodiments, the controller 210 may measure the strength of a signal related to the phased array antenna 100 . For example, the controller 210 may measure the strength of a signal transmitted from each RF chain in the phased array antenna 100, and may measure the strength of a combined signal of signals transmitted from two or more RF chains. have. Here, the combined signal may be expressed as a vector sum of signals. As another example, the controller 210 may measure the strength of a signal received by each RF chain from the phased array antenna 100 and may measure the strength of a combined signal of signals received by two or more RF chains.

According to various embodiments of the present disclosure, the strength of the signal y may refer to the magnitude (|y|) of the signal y or the power (y ² ) of the signal y. In other words, the strength of the signal may include at least one of the magnitude of the signal and the power of the signal. In addition, according to various embodiments of the present disclosure, a signal related to an element (eg, an RF chain, a phased array antenna, a communication device) may refer to a signal transmitted or received from the element. For example, a signal related to a reference RF chain means a signal transmitted from the reference RF chain or a signal received by the reference RF chain. The signal related to the target RF chain means a signal transmitted from the target RF chain or a signal received by the target RF chain. According to various embodiments, a signal related to a reference RF chain may be referred to as a 'reference signal', and a signal related to a target RF chain may be referred to as a 'test signal'.

The transceiver 220 may transmit or receive a signal through the reference antenna 230 . For example, the transceiver 220 may generate a calibration signal for calibrating the phased array antenna 100 . The transceiver 220 may provide the generated calibration signal to the phased array antenna 100 so that the signal is transmitted from the RF chains in the on state of the phased array antenna 100 . The transceiver 220 may receive a signal transmitted from the phased array antenna 100 through the reference antenna 230 and may provide information about the received signal to the controller 210 . As another example, the transceiver 220 may transmit a calibration signal through the reference antenna 230 . The transceiver 220 may enable the phased array antenna 100 to receive a signal transmitted from the reference antenna 230, and may provide information about the signal received by the upper array antenna 100 to the controller 210 . For example, the transceiver 220 may include transmit filters, receive filters, amplifiers, mixers, oscillators, digital to analog converters (DACs), analog to digital converters (ADCs), etc. to generate, transmit and/or receive signals. can

2B illustrates a second configuration of a calibration apparatus 200 according to various embodiments of the present disclosure. Terms such as '~ unit' and '~ group' used below mean a unit for processing at least one function or operation, which may be implemented as hardware or software, or a combination of hardware and software.

Referring to FIG. 2B , the calibration device 200 may be a communication device including the phased array antenna 100 . In other words, the calibration apparatus 200 may self-calibrate the phased array antenna 100 included in the calibration apparatus 200 . For example, the communication device may be a base station or a terminal. According to various embodiments of the present disclosure, a base station is an 'access point (AP)', an 'eNodeB (eNodeB)', a '5G node (5th generation node)', a 'wireless It may be referred to as a 'wireless point', a 'transmission/reception point (TRP)' or other terms having an equivalent technical meaning. In addition to terminals, terminals are 'user equipment (UE)', 'mobile station', 'subscriber station', 'remote terminal', 'wireless terminal' )', 'customer premises equipment (CPE)', or 'user device' or other terms having an equivalent technical meaning. When the calibration device 200 is a communication device including the phased array antenna 100, the calibration device 200 may include a communication unit 250, a storage unit 260, and a control unit 270.

The communication unit 250 performs functions for transmitting and receiving signals through a wireless channel. For example, the communication unit 250 performs a function of converting between a baseband signal and a bit stream according to a physical layer standard of a system. For example, when transmitting data, the communication unit 250 generates complex symbols by encoding and modulating the transmitted bit stream. In addition, when receiving data, the communication unit 250 restores the received bit stream by demodulating and decoding the baseband signal. In addition, the communication unit 250 up-converts the baseband signal into an RF band signal, transmits the signal through the antenna, and downconverts the RF band signal received through the antenna into a baseband signal. For example, the communication unit 250 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like.

Also, the communication unit 250 may include a plurality of transmission/reception paths. Furthermore, the communication unit 250 may include at least one antenna array (eg, the phased array antenna 100) configured with a plurality of antenna elements. In other words, the communication unit 250 may include a plurality of RF chains, and may perform beamforming based on the phased array antenna 100 and/or the plurality of RF chains. In terms of hardware, the communication unit 250 may include a digital circuit and an analog circuit (eg, a radio frequency integrated circuit (RFIC)). Here, the digital circuit and the analog circuit may be implemented as one package.

The communication unit 250 transmits and receives signals as described above. Accordingly, all or part of the communication unit 250 may be referred to as a 'transmitter', 'receiver', or 'transceiver'. In addition, in the following description, transmission and reception performed through a wireless channel are used in the meaning of including processing as described above by the communication unit 250 .

According to various embodiments of the present disclosure, the communication unit 250 may perform the same or similar function to the transceiver 220 . For example, the communication unit 250 may provide a calibration signal to the phased array antenna 100 and detect the calibration signal processed by the phased array antenna 100 through a feedback loop 280 . As another example, the communication unit 250 may provide a calibration signal to the phased array antenna 100 through the feedback loop 280 and detect a signal processed by the phased array antenna 100 . The communication unit 250 may provide a government related to the detected signal to the control unit 270 .

The storage unit 260 stores data such as a basic program, an application program, and setting information for the operation of the calibration device. The storage unit 260 may be configured as a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. In addition, the storage unit 260 provides the stored data according to the request of the control unit 270 .

The controller 270 controls overall operations of the calibration apparatus. For example, the control unit 270 transmits and receives signals through the communication unit 250 . In addition, the control unit 270 writes and reads data in the storage unit 260 . In addition, the controller 270 may perform functions of the protocol stack required by the communication standard. To this end, the controller 270 may include at least one processor or microprocessor, or may be a part of the processor. Also, a part of the communication unit 250 and the control unit 270 may be referred to as a communication processor (CP).

According to various embodiments of the present disclosure, the control unit 270 may perform the same or similar function as the control unit 210 . For example, the controller 270 may control the communication unit 250 to generate a calibration signal. Also, the controller 270 may control the communication unit 250 to provide a calibration signal to the phased array antenna 100 or to detect a calibration signal through the phased array antenna 100 . As another example, the controller 270 may control the communication unit 250 to provide the calibration signal to the phased array antenna 100 through the feedback loop 280 or to detect the calibration signal processed by the phased array antenna 100 through the feedback loop 280 .

Although not shown, when the calibration apparatus 200 is a base station, the calibration apparatus 200 may further include a backhaul communication unit. The backhaul communication unit may provide an interface for performing communication with other nodes in the network. That is, the backhaul communication unit converts a bit string transmitted from a base station to another node, for example, another access node, another base station, upper node, core network, etc. into a physical signal, and converts a physical signal received from another node into a bit string. can be converted

As another example, even if the calibration apparatus 200 is a base station, the calibration apparatus 200 may not include a backhaul communication unit. In this case, the calibration device 200 uses the communication unit 250 to communicate with other nodes in the network (eg, other access nodes, other base stations, upper nodes, core networks) through wireless backhaul, which is a kind of wireless channel. can

According to various embodiments, the controller 210 and/or the controller 270 estimates candidate codes for a calibration code of the target RF chain by using some of the phase codes among possible phase codes that can be set in the target RF chain, and selects the candidate codes. An optimal calibration code among candidate codes may be determined from among candidate codes in consideration of an error for , and the target RF chain may be calibrated by setting the calibration code to the target RF chain. For example, the controller 210 and/or the controller 270 may control the calibration apparatus to perform operations according to various embodiments to be described later.

The calibration apparatus may select one of the RF chains of the phased array antenna as a reference RF chain and select the other one as a target RF chain for calibration. After the calibration apparatus completes the calibration for the selected target RF chain, it may sequentially calibrate the remaining RF chains one by one. Calibration for the target RF chain is to set the phase code in the target RF chain so that when signals of the same phase are input to the target RF chain and the reference RF chain, the signals passing through the target RF chain and the reference RF chain all have the same phase. means that When the phase of the signal (hereinafter referred to as 'test signal for specific phase code') related to the target RF chain for which a specific phase code is set is the same as the phase of the reference signal (hereinafter referred to as 'reference phase'), The strength of the combined signal of the test signal and the reference signal may be maximized. As another example, when the difference between the phase of the test signal and the reference phase for a specific phase code is 180°, the strength of the combined signal of the test signal and the reference signal may be minimized.

According to various embodiments of the present disclosure, a phase code to be set in the target RF chain in order for the phase of the test signal to be the same as the reference phase may be referred to as a 'calibration code' or an 'optimal phase code'. In addition, the 'combination signal of the test signal and the reference signal' means a vector sum and/or combination of the test signal and the reference signal, and may be briefly referred to as a 'combination signal' in the present disclosure. Furthermore, the combination signal of the reference signal and the test signal for a specific phase code may be briefly referred to as a 'combination signal for a specific phase code'.

In order to calibrate the target RF chain, the calibration device must determine a calibration code of the target RF chain. For example, the calibration apparatus may determine a phase code (ie, a calibration code) in which the strength of the combined signal is maximized, based on all possible phase codes that may be set in the target RF chain. According to various embodiments of the present disclosure, possible phase codes that may be set in the target RF chain may be referred to as possible phase codes of the target RF chain. As another example, the calibration apparatus determines a phase code in which the strength of the combined signal is minimized based on all possible phase codes that can be set in the target RF chain, and a calibration code having a code difference of 180° with respect to the determined phase code. can be decided

Since the above-described calibration methods consider all possible phase codes that can be set in the target RF chain, it may take a lot of time (hereinafter, referred to as a 'calibration time') to calibrate the target RF chain. Accordingly, various embodiments of the present disclosure provide an apparatus capable of estimating candidate codes for a calibration code of a target RF chain by using some of the phase codes among possible phase codes that can be set in the target RF chain in order to reduce the calibration time and methods. In various embodiments of the present disclosure, a 'candidate code' means a phase code estimated as a calibration code using some of the phase codes that can be set in the target RF chain. For example, the calibration apparatus according to various embodiments of the present disclosure may estimate a candidate code for a calibration code of a target RF chain using a pair of phase codes as illustrated in FIG. 4 .

When the calibration apparatus estimates a calibration code by using some of the phase codes among possible phase codes that can be set in the target RF chain, reliability or relevance for the estimated calibration code may be a problem. For example, if a measurement error occurs in a situation where the strength of the combined signal is measured by setting a specific phase code in the target RF chain, the strength of the wrong combination signal may be estimated, and a candidate estimated based on the strength of the combined signal The code can also be a fail code. Accordingly, various embodiments of the present disclosure estimate a plurality of candidate codes for a calibration code in order to increase reliability or validity of the estimated calibration code, and a candidate code having the smallest error in consideration of an error with respect to each candidate code. An apparatus and method for determining ? as a calibration code are provided. In addition, various embodiments of the present disclosure determine the validity of the measured value and/or the estimated value based on the measured value (eg, the validity of the reference signal strength, the validity of the test signal strength, the validity of the code difference between candidate codes). An apparatus and method for doing so are provided.

The calibration device may calibrate an external phased array antenna (eg factory calibration). In addition, when the calibration device is a communication device such as a base station and/or a terminal, the calibration device may include a phased array antenna therein, and self-calibrate the phased array antenna included therein (eg, self-calibration). (self-calibration)). Furthermore, when the calibration device is a communication device, the calibration device transmits a combined signal or an individual signal related to a single RF chain to another communication device for calibration of the phased array antenna included therein, and the signal measured by the other communication device , may receive information about the device from another communication device, and calibrate the phased array antenna based on the received information (eg, online calibration). Various embodiments of the present disclosure may include factory calibration, self-calibration and An apparatus and method for performing online calibration are provided.

Hereinafter, an operation method of a calibration apparatus for estimating a candidate code for the calibration code and determining the calibration code in consideration of an error with respect to the candidate code will be described with reference to FIG. 3 .

3 is a flowchart illustrating a calibration apparatus according to various embodiments of the present disclosure. 3 illustrates an operation method of the calibration apparatus 200 .

Referring to FIG. 3 , in step 301 , the calibration apparatus sets phase codes in the target RF chain to estimate at least one candidate code for the calibration code of the target RF chain. For example, the calibration apparatus may set each pair of phase codes in the target RF chain, and estimate a candidate code for the calibration code of the target RF chain using the pair of phase codes. A specific method for estimating a candidate code for a calibration code will be described in more detail with reference to FIGS. 4 and 5A and 5B below.

In step 303, the calibration apparatus is configured to have an error between the intensity of the first combined signal estimated for the phase codes and the intensity of the second combined signal measured with respect to the phase codes under the condition that the reference phase corresponds to at least one candidate code. to decide In other words, the calibration apparatus may determine an error with respect to the estimated candidate code. When it is assumed that the reference phase corresponds to the estimated candidate code (ie, it is not known whether the reference phase actually corresponds to the estimated candidate code), the calibration apparatus theoretically calculates the strength of the combined signal for each of the phase codes. (theoretically) can be inferred. Also, the calibration apparatus may actually measure the intensity of the combined signal for each of the phase codes to obtain the measured intensity of the combined signal. The calibration apparatus may determine an error between the theoretically estimated intensity of the combined signal for each of the phase codes and the actually measured intensity of the combined signal.

In step 305, the calibration device determines a calibration code based on the error. For example, the calibration apparatus may determine errors with respect to a plurality of candidate codes, and may determine a candidate code having the smallest error among the plurality of candidate codes as the calibration code. A specific method of determining an error for a candidate code and determining a calibration code based on the error will be described in more detail with reference to FIGS. 6 and 7A and 7B below.

In step 307, the calibration device sets the calibration code in the target RF chain to calibrate the target RF chain. In other words, the calibration device may set the calibration code in the target RF chain so that the phase of the test signal is the same as the reference phase. Although not shown, after step 307, the calibration apparatus may select another RF chain on which calibration is not performed, and calibrate the selected RF chain.

4 is a flowchart for determining a candidate code for a calibration code according to various embodiments of the present disclosure. 4 illustrates an operation method of the calibration apparatus 200 . In FIG. 4 , the first phase code and the second phase code are phase codes that can be set in the target RF chain, and a candidate code for the calibration code of the target RF chain is estimated based on the first phase code and the second phase code. do.

Referring to FIG. 4 , in step 401 , the calibration apparatus determines a phase difference between a phase corresponding to the first phase code and a reference phase based on the strength of the combined signal measured for the first phase code. The phase corresponding to the first phase code may lead or lag the reference phase.

In operation 403 , the calibration apparatus determines a phase state of the phase difference based on the strength of the combined signal measured for the second phase code. According to various embodiments of the present disclosure, the phase state of the phase difference may indicate which phase of the phases based on the phase difference precedes and which phase is delayed. For example, the calibration apparatus may determine whether a phase corresponding to the first phase code precedes or delays a reference phase.

In step 405, the calibration apparatus estimates a candidate code for the calibration code based on the phase difference and the phase state of the phase difference. For example, when the phase corresponding to the first phase code precedes the reference phase, the calibration apparatus estimates a phase code that causes the phase corresponding to the first phase code to be delayed by a phase difference as a candidate code for the calibration code. can As another example, when the phase corresponding to the first phase code is delayed from the reference phase, the calibration apparatus may estimate a phase code that advances the phase corresponding to the first phase code by a phase difference as a candidate code for the calibration code. have.

As described above, the calibration apparatus may estimate a candidate code for the calibration code based on a pair of phase codes (eg, a first phase code and a second phase code). The calibration apparatus may estimate a candidate code for the calibration code based on different pairs of phase codes. In this case, respective candidate codes determined based on different pairs of phase codes may be the same or different from each other. .

5A and 5B illustrate graphs for representing estimation of a candidate code according to various embodiments of the present disclosure; In the graphs 510 and 520 of FIGS. 5A and 5B , the horizontal axis indicates a phase corresponding to the phase code set in the target RF chain, and the vertical axis indicates the strength of the combined signal.

5A and 5B, in order to estimate the first candidate code 521 and the second candidate code 523 for the calibration code of the target RF chain, the first phase code 511, the second phase code 513, and the third phase code 515 can be considered. For convenience of explanation, the code difference between the first phase code 511 and the second phase code 513 corresponds to a phase difference of 90°, and the code difference between the second phase code 513 and the third phase code 515 corresponds to a phase difference of 90° This is assumed However, this is exemplary, and the code difference of phase codes required to be set in the target RF chain in order to estimate the calibration code of the target RF chain may correspond to a phase difference other than 90°.

First, the calibration apparatus may set the first phase code 511 in the target RF chain and measure the intensity y ₁ of the combined signal with respect to the first phase code 511 . The calibration apparatus may determine the phase difference between the phase corresponding to the first phase code 511 and the reference phase based on the intensity y ₁ of the combined signal with respect to the first phase code 511 as shown in Equation 1 below:

은 제1 위상 코드 511에 대응하는 위상과 기준 위상간 위상 차, y₁은 제1 위상 코드 511에 대한 조합 신호의 세기,

은 기준 신호의 세기,

는 테스트 신호의 세기를 의미한다.From here,

is the phase difference between the phase corresponding to the first phase code 511 and the reference phase, y ₁ is the strength of the combined signal with respect to the first phase code 511,

is the strength of the reference signal,

is the strength of the test signal.

Next, the calibration apparatus may set the second phase code 513 in the target RF chain and measure the intensity y ₂ of the combined signal with respect to the second phase code 513 . The calibration apparatus determines the phase state of the phase difference between the phase corresponding to the first phase code 511 and the reference phase based on the intensity y ₂ of the combined signal with respect to the second phase code 513 as shown in Equation 2 below. It is possible to determine a reference value for:

은 제1 위상 코드 511에 대응하는 위상과 기준 위상간 위상 차, y₂는 제2 위상 코드 513에 대한 조합 신호의 세기,

은 기준 신호의 세기,

는 테스트 신호의 세기,

는 위상 차

의 위상 상태를 결정하기 위한 기준 값을 의미한다. 만약,

>0인 경우, 제1 위상 코드 511에 대응하는 위상은 기준 위상보다 지연된다.

<0인 경우, 제1 위상 코드 511에 대응하는 위상은 기준 위상보다 선행한다. From here,

is the phase difference between the phase corresponding to the first phase code 511 and the reference phase, y ₂ is the strength of the combined signal with respect to the second phase code 513,

is the strength of the reference signal,

is the strength of the test signal,

is the phase difference

It means a reference value for determining the phase state of . what if,

When >0, the phase corresponding to the first phase code 511 is delayed from the reference phase.

When <0, the phase corresponding to the first phase code 511 precedes the reference phase.

Based on the phase difference between the phase corresponding to the first phase code 511 and the reference phase and the phase state of the phase difference, the calibration apparatus may determine the phase corresponding to the first candidate code 521 as shown in Equation 3 below. have:

은 제1 후보 코드 521에 대응하는 위상,

는 제1 위상 코드 511에 대응하는 위상,

은 제1 위상 코드 511에 대응하는 위상과 기준 위상간 위상 차를 의미한다. <수학식 3>에서, 제1 위상 코드 511에 대응하는 위상이 기준 위상보다 지연될 경우, '+' 부호가 적용된다. 반면, 제1 위상 코드 511에 대응하는 위상이 기준 위상보다 선행할 경우, '-'부호가 적용된다. 제1 후보 코드 521은 위상

과 제1 후보 코드 521간 대응 관계를 이용하여 결정될 수 있다.From here,

is the phase corresponding to the first candidate code 521;

is the phase corresponding to the first phase code 511,

denotes a phase difference between the phase corresponding to the first phase code 511 and the reference phase. In <Equation 3>, when the phase corresponding to the first phase code 511 is delayed from the reference phase, a '+' sign is applied. On the other hand, when the phase corresponding to the first phase code 511 precedes the reference phase, a '-' sign is applied. The first candidate code 521 is a phase

and the first candidate code 521 may be determined using a correspondence relationship.

In addition, the calibration apparatus may determine the phase difference between the phase corresponding to the second phase code 513 and the reference phase based on the intensity y ₂ of the combined signal with respect to the second phase code 513 as shown in Equation 4 below. :

는 제2 위상 코드 513에 대응하는 위상과 기준 위상간 위상 차, y₂는 제2 위상 코드 513에 대한 조합 신호의 세기,

은 기준 신호의 세기,

는 테스트 신호의 세기를 의미한다. 본 예시에서,

=

+90°의 관계가 성립한다.From here,

is the phase difference between the phase corresponding to the second phase code 513 and the reference phase, y ₂ is the strength of the combined signal with respect to the second phase code 513,

is the strength of the reference signal,

is the strength of the test signal. In this example,

=

A relation of +90° holds.

Next, the calibration apparatus may measure the intensity y ₃ of the combined signal with respect to the third phase code 515 by setting the third phase code 515 in the target RF chain. The calibration apparatus determines the phase state of the phase difference between the phase corresponding to the second phase code 513 and the reference phase based on the intensity y ₃ of the combined signal for the third phase code 515, as shown in Equation 5 below. It is possible to determine a reference value for:

는 제2 위상 코드 513에 대응하는 위상과 기준 위상간 위상 차, y₃은 제3 위상 코드 515에 대한 조합 신호의 세기,

은 기준 신호의 세기,

는 테스트 신호의 세기,

는 위상 차

의 위상 상태를 결정하기 위한 기준 값을 의미한다. 만약,

>0인 경우, 제2 위상 코드 513에 대응하는 위상은 기준 위상보다 지연된다.

<0인 경우, 제2 위상 코드 513에 대응하는 위상은 기준 위상보다 선행한다.From here,

is the phase difference between the phase corresponding to the second phase code 513 and the reference phase, y ₃ is the strength of the combined signal with respect to the third phase code 515,

is the strength of the reference signal,

is the strength of the test signal,

is the phase difference

It means a reference value for determining the phase state of . what if,

If >0, the phase corresponding to the second phase code 513 is delayed from the reference phase.

When <0, the phase corresponding to the second phase code 513 precedes the reference phase.

Based on the phase difference between the phase corresponding to the second phase code 513 and the reference phase and the phase state of the phase difference, the calibration apparatus may determine the phase corresponding to the second candidate code 523 as shown in Equation 6 below. have;

는 제2 후보 코드 523에 대응하는 위상,

은 제2 위상 코드 513에 대응하는 위상,

는 제2 위상 코드 513에 대응하는 위상과 기준 위상간 위상 차,

는 제1 위상 코드 511에 대응하는 위상을 의미한다. <수학식 6>에서, 제2 위상 코드 513에 대응하는 위상이 기준 위상보다 지연될 경우, '+'부호가 적용된다. 반면, 제2 위상 코드 513에 대응하는 위상이 기준 위상보다 선행할 경우, '-'부호가 적용된다. 제2 후보 코드 523은 위상

와 제2 후보 코드 523간 대응 관계를 이용하여 결정될 수 있다.From here,

is the phase corresponding to the second candidate code 523;

is the phase corresponding to the second phase code 513,

is the phase difference between the phase corresponding to the second phase code 513 and the reference phase,

denotes a phase corresponding to the first phase code 511. In <Equation 6>, when the phase corresponding to the second phase code 513 is delayed from the reference phase, a '+' sign is applied. On the other hand, when the phase corresponding to the second phase code 513 precedes the reference phase, a '-' sign is applied. The second candidate code 523 is a phase

and the second candidate code 523 may be determined using a correspondence relationship.

In the above-described examples, three phase codes (eg, first phase code 511, second phase code 513, A third phase code 515) has been used, but this is exemplary and more than three phase codes may be used. For example, in order to estimate each candidate code, it is required to set two phase codes in the target RF chain to measure the strength of the combined signal for the two phase codes, so to estimate the two candidate codes, four phase codes are Codes can be used. In addition, although two candidate codes are estimated in the above-described examples, more than two candidate codes may be estimated.

6 is a flowchart for determining an error for a candidate code according to various embodiments of the present disclosure. 6 illustrates an operation method of the calibration apparatus 200 . In FIG. 6 , it is assumed that the first candidate code and the second candidate code for the calibration code of the target RF chain are estimated based on the phase codes set in the target RF chain.

Referring to FIG. 6 , in step 601 , the calibration apparatus determines a period between the intensity of the combined signal estimated for the phase codes and the intensity of the combined signal measured with respect to the phase codes under the condition that the first candidate code corresponds to the reference phase. Determine the first error. In other words, the calibration apparatus may determine an error with respect to the estimated first candidate code. When it is assumed that the reference phase corresponds to the first candidate code (ie, it is not known whether the reference phase actually corresponds to the first candidate code), the calibration apparatus theoretically calculates the strength of the combined signal for each of the phase codes. can be estimated Also, the calibration apparatus may measure the intensity of the combined signal for each of the phase codes to obtain the measured intensity of the combined signal. The calibration apparatus may determine a first error between the theoretically estimated intensity of the combined signal for each of the phase codes and the actually measured intensity of the combined signal.

In step 603, the calibration apparatus determines a second error between the intensity of the combined signal estimated for the phase codes and the intensity of the combined signal measured with respect to the phase codes under the condition that the second candidate code corresponds to the reference phase. . In other words, the calibration apparatus may determine an error with respect to the estimated second candidate code. The calibration apparatus may determine the second error using a method similar to the method of determining the first error.

In step 605, the calibration device determines whether the first error is less than the second error. In other words, the calibration apparatus may compare the first error with respect to the first candidate code and the second error with respect to the second candidate code.

When the first error is smaller than the second error, in step 607, the calibration apparatus determines the first candidate code as the calibration code. In other words, when the first error with respect to the first candidate code is smaller than the second error with respect to the second candidate code, the calibration apparatus determines that the phase corresponding to the first candidate code is in the reference phase rather than the phase corresponding to the second candidate code. It may be determined that it is closer, and the first candidate code may be determined as the calibration code.

When the first error is greater than the second error, in step 609, the calibration apparatus determines the second candidate code as the calibration code. In other words, when the second error with respect to the second candidate code is smaller than the first error with respect to the first candidate code, the calibration apparatus determines that the phase corresponding to the second candidate code is in the reference phase rather than the phase corresponding to the first candidate code. It may be determined that it is closer, and the second candidate code may be determined as the calibration code.

Although not shown, the calibration apparatus may apply the determined calibration code to the target RF chain to complete calibration for the target RF chain.

7A and 7B are graphs illustrating errors for estimated candidate codes according to various embodiments of the present disclosure; In the graphs 710 and 720 of FIGS. 7A and 7B , the horizontal axis indicates a phase corresponding to the phase code set in the target RF chain, and the vertical axis indicates the strength of the combined signal. 7A and 7B , the first candidate code 521 is estimated based on the first phase code 511 and the second phase code 513 set in the target RF chain, and the second phase code 513 and the third phase code 515 set in the target RF chain It is assumed that the second candidate code 523 is estimated based on .

Referring to FIG. 7A , in the graph 710, a function of the combined signal strength for the first candidate code 521 and a function of the combined signal strength for the second candidate code 523 are illustrated. According to various embodiments of the present disclosure, a function of the combined signal strength for the first candidate code 521 is, under the condition that the first candidate code 521 corresponds to the reference phase, the combined signal strength for possible phase codes of the target RF chain means a function of In other words, the function of the combined signal strength for the first candidate code 521 is assuming that the first candidate code 521 corresponds to the reference phase (ie, it is not known whether the first candidate code 521 actually corresponds to the reference phase) ), means a function of the strength of the combined signal for the possible phase codes of the target RF chain. A function of the combined signal strength for the second candidate code 523 may also be defined in a similar way.

In more detail, the function of the combined signal strength for the first candidate code 521 may be expressed as in Equation 7 below:

는 제1 후보 코드 521에 대한 조합 신호 세기의 함수,

은 제1 후보 코드 521에 대응하는 위상,

는 대상 RF 체인에 설정된 위상 코드에 대응하는 위상,

은 기준 신호의 세기,

는 테스트 신호의 세기를 의미한다.

는 0°부터 360°의 범위 이내에서 존재한다.From here,

is a function of the combined signal strength for the first candidate code 521,

is the phase corresponding to the first candidate code 521;

is the phase corresponding to the phase code set in the target RF chain,

is the strength of the reference signal,

is the strength of the test signal.

is within the range of 0° to 360°.

Similarly, a function of the combined signal strength for the second candidate code 523 may be expressed as in Equation 8 below:

는 제2 후보 코드 523에 대한 조합 신호 세기의 함수,

는 제2 후보 코드 523에 대응하는 위상,

는 대상 RF 체인에 설정된 위상 코드에 대응하는 위상,

은 기준 신호의 세기,

는 테스트 신호의 세기를 의미한다.

는 0°부터 360°의 범위 이내에서 존재한다.From here,

is a function of the combined signal strength for the second candidate code 523,

is the phase corresponding to the second candidate code 523;

is the phase corresponding to the phase code set in the target RF chain,

is the strength of the reference signal,

is the strength of the test signal.

is within the range of 0° to 360°.

이고, 제2 위상 코드 513에서 제1 후보 코드 521에 대한 조합 신호 세기의 함수의 값은

이고, 제3 위상 코드 515에서 제1 후보 코드 521에 대한 조합 신호 세기의 함수의 값은

로 표현될 수 있다. 여기에서,

는 제1 후보 코드 521에 대한 조합 신호 세기의 함수,

은 제1 후보 코드 521에 대응하는 위상,

는 제1 위상 코드 511에 대응하는 위상을 의미한다.Referring to FIG. 7B , in graph 720, an error with respect to a first candidate code 521 and an error with respect to a second candidate code 523 are shown. The error for the first candidate code 521 is an error between the intensity of the combined signal estimated for the phase codes and the intensity of the combined signal measured for the phase codes under the condition that the first candidate code 521 corresponds to the reference phase. can For example, the strength of the combined signal measured for the first phase code 511 is y ₁ , the strength of the combined signal measured for the second phase code 513 is y ₂ , and the combination measured for the third phase code 515 is y 1 . The signal strength may be y ₃ . Under the condition that the first candidate code 521 corresponds to the reference phase, the estimated combined signal strength for the phase codes may be a value of a function of the combined signal strength for the first candidate code 521 in the phase codes. For example, the value of the function of the combined signal strength for the first candidate code 521 in the first phase code 511 is

, and the value of the function of the combined signal strength for the first candidate code 521 in the second phase code 513 is

and the value of the function of the combined signal strength for the first candidate code 521 in the third phase code 515 is

can be expressed as From here,

is a function of the combined signal strength for the first candidate code 521,

is the phase corresponding to the first candidate code 521;

denotes a phase corresponding to the first phase code 511.

이고, 제2 위상 코드 513에서 제2 후보 코드 523에 대한 조합 신호 세기의 함수의 값은

이고, 제3 위상 코드 515에서 제2 후보 코드 523에 대한 조합 신호 세기의 함수의 값은

로 표현될 수 있다. 여기에서,

는 제1 후보 코드 521에 대한 조합 신호 세기의 함수,

는 제2 후보 코드 523,

는 제1 위상 코드 511에 대응하는 위상을 의미한다.Similarly, the error for the second candidate code 523 is determined by determining the combined signal strength estimated for the phase codes under the condition that the second candidate code 523 corresponds to the reference phase, and the measured combined signal strength for the phase codes. It could be a period error. Under the condition that the second candidate code 523 corresponds to the reference phase, the estimated combined signal strength for the phase codes may be a value of the combined signal strength function for the second candidate code 523 in the phase codes. For example, the value of the function of the combined signal strength for the second candidate code 523 in the first phase code 511 is

, and the value of the function of the combined signal strength for the second candidate code 523 in the second phase code 513 is

, and the value of the function of the combined signal strength for the second candidate code 523 in the third phase code 515 is

can be expressed as From here,

is a function of the combined signal strength for the first candidate code 521,

is the second candidate code 523,

denotes a phase corresponding to the first phase code 511.

Based on the above results, the error with respect to the first candidate code 521 may be expressed as in Equation 9 below:

은 제1 후보 코드 521에 대한 오차,

은 위상 코드들에 대해 측정된 신호 세기 벡터(이하, '측정된 신호 세기 벡터'로 지칭된다),

은 제1 후보 코드 521이 기준 위상에 대응한다는 조건 하에서 위상 코드들에 대해 추정된 신호 세기 벡터(이하, '제1 후보 코드 521과 관련된 신호 세기 벡터'로 지칭된다)를 의미한다.From here,

is the error for the first candidate code 521,

is the measured signal strength vector for the phase codes (hereinafter referred to as 'measured signal strength vector'),

denotes a signal strength vector (hereinafter, referred to as a 'signal strength vector associated with the first candidate code 521') estimated for the phase codes under the condition that the first candidate code 521 corresponds to the reference phase.

An error with respect to the second candidate code 523 may be expressed as in Equation 10 below:

는 제2 후보 코드 523에 대한 오차,

은 위상 코드들에 대해 측정된 신호 세기 벡터,

은 제2 후보 코드 523이 기준 위상에 대응한다는 조건 하에서 위상 코드들에 대해 추정된 신호 세기 벡터(이하, '제2 후보 코드 523과 관련된 신호 세기 벡터'로 지칭된다)를 의미한다.From here,

is the error for the second candidate code 523,

is the measured signal strength vector for the phase codes,

denotes a signal strength vector estimated for the phase codes under the condition that the second candidate code 523 corresponds to the reference phase (hereinafter, referred to as a 'signal strength vector associated with the second candidate code 523').

는 하기의 <수학식 11>과 같이 표현될 수 있다:Measured signal strength vector for phase codes

can be expressed as the following <Equation 11>:

은 위상 코드들에 대해 측정된 신호 세기 벡터, y₁은 제1 위상 코드 511에 대해 측정된 조합 신호의 세기, y₂는 제2 위상 코드 513에 대해 측정된 조합 신호의 세기, y₃은 제3 위상 코드 515에 대해 측정된 조합 신호의 세기를 의미한다.From here,

is the signal strength vector measured for the phase codes, y ₁ is the strength of the combined signal measured for the first phase code 511, y ₂ is the strength of the combined signal measured for the second phase code 513, y ₃ is the strength of the combined signal measured for the second phase code 513 3 Means the strength of the combined signal measured with respect to the phase code 515.

은 하기의 <수학식 12>와 같이 표현될 수 있다:Estimated signal strength vector for phase codes under the condition that the first candidate code 521 corresponds to the reference phase

can be expressed as the following <Equation 12>:

은 제1 후보 코드 521이 기준 위상에 대응한다는 조건 하에서 위상 코드들에 대해 추정된 신호 세기 벡터,

은 제1 후보 코드 521에 대응하는 위상,

는 제1 위상 코드 511에 대응하는 위상,

는 제1 후보 코드 521이 기준 위상에 대응한다는 조건 하에서 제1 위상 코드 511에 대해 추정된 조합 신호의 세기,

는 제1 후보 코드 521이 기준 위상에 대응한다는 조건 하에서 제2 위상 코드 513에 대해 추정된 조합 신호의 세기,

은 제1 후보 코드 521이 기준 위상에 대응한다는 조건 하에서 제3 위상 코드 515에 대해 추정된 조합 신호의 세기를 의미한다. From here,

is the estimated signal strength vector for the phase codes under the condition that the first candidate code 521 corresponds to the reference phase,

is the phase corresponding to the first candidate code 521;

is the phase corresponding to the first phase code 511,

is the strength of the combined signal estimated for the first phase code 511 under the condition that the first candidate code 521 corresponds to the reference phase,

is the strength of the combined signal estimated for the second phase code 513 under the condition that the first candidate code 521 corresponds to the reference phase,

is the intensity of the combined signal estimated with respect to the third phase code 515 under the condition that the first candidate code 521 corresponds to the reference phase.

은 하기의 <수학식 13>와 같이 표현될 수 있다:Similarly, the estimated signal strength vector for the phase codes under the condition that the second candidate code 523 corresponds to the reference phase.

can be expressed as the following <Equation 13>:

은 제2 후보 코드 523이 기준 위상에 대응한다는 조건 하에서 위상 코드들에 대해 추정된 신호 세기 벡터,

는 제2 후보 코드 523,

는 제1 위상 코드 511에 대응하는 위상,

는 제2 후보 코드 523이 기준 위상에 대응한다는 조건 하에서 제1 위상 코드 511에 대해 추정된 조합 신호의 세기,

는 제2 후보 코드 523이 기준 위상에 대응한다는 조건 하에서 제2 위상 코드 513에 대해 추정된 조합 신호의 세기,

은 제2 후보 코드 523이 기준 위상에 대응한다는 조건 하에서 제3 위상 코드 515에 대해 추정된 조합 신호의 세기를 의미한다. From here,

is the estimated signal strength vector for the phase codes under the condition that the second candidate code 523 corresponds to the reference phase,

is the second candidate code 523,

is the phase corresponding to the first phase code 511,

is the strength of the combined signal estimated for the first phase code 511 under the condition that the second candidate code 523 corresponds to the reference phase,

is the strength of the combined signal estimated for the second phase code 513 under the condition that the second candidate code 523 corresponds to the reference phase,

is the intensity of the combined signal estimated with respect to the third phase code 515 under the condition that the second candidate code 523 corresponds to the reference phase.

In the above-described examples, the error is expressed as a least square error (LSE), but this is exemplary, and the error is the difference between the intensity of the combined signal estimated for the phase codes and the intensity of the combined signal measured for the phase codes. It can also be expressed as the sum of all . As another example, the error may be determined based on a correlation coefficient between the intensity of the combined signal estimated with respect to the phase codes and the intensity of the combined signal measured with respect to the phase codes. The calibration apparatus may determine a correlation coefficient for each candidate code, and determine that a candidate code having a higher correlation coefficient has a lower error.

According to various embodiments of the present disclosure, the calibration apparatus may estimate the strength of the test signal based on the strength of the combined signal measured with respect to the phase codes. In other words, the calibration apparatus may not directly measure the strength of the test signal, but may estimate the strength of the test signal based on the strength of the combined signal measured with respect to the phase codes. Since the strength of the test signal cannot be properly estimated when the measurement of the signal strength is incorrect, the calibration apparatus may inversely determine whether the measurement of the signal strength is incorrect based on the validity of the estimated strength of the test signal.

8 illustrates examples of calibration results according to various embodiments of the present disclosure. In graphs 810 and 820, the horizontal axis indicates the phase code set in the target RF chain, and the vertical axis indicates the strength of the combined signal.

Referring to the graph 810 , the intensity of the reference signal and the intensity of the test signal are similar. In other words, the graph 810 represents a case in which the strength of the test signal is appropriately estimated. When the strength of the test signal is appropriately estimated, it may be determined that the measurement result of the strength of the combined signal used for estimating the strength of the test signal is valid, and accordingly, candidate codes based on the strength of the combined signal may also be appropriately estimated. . Accordingly, according to the graph 810, the function of the combined signal strength for the candidate code is similar to the measured combined signal strength, and the error for the candidate code may be small.

Referring to the graph 820 , the intensity of the reference signal and the intensity of the test signal are significantly different. In other words, the graph 820 represents a case in which the strength of the test signal is not properly estimated. If the strength of the test signal is not properly estimated, it may be determined that the measurement result of the strength of the combined signal used for estimating the strength of the test signal is not valid, and therefore candidate codes based on the strength of the combined signal may also be appropriately estimated. can't Accordingly, according to the graph 820, the strength function of the combined signal with respect to the candidate code is different from the measured strength of the combined signal, and the error with respect to the candidate code may be large.

According to various embodiments of the present disclosure, when an RF chain is broken or a phase shifter phasing (PS phasing) fails, the strength of the test signal may be incorrectly estimated. As another example, when the signal strength (eg, the strength of the combined signal, the strength of the reference signal) is measured incorrectly, the phase code set in the target RF chain is incorrectly controlled, or the measurement setup is incorrect, the strength of the test signal may be incorrectly estimated.

Hereinafter, with reference to FIG. 9 , the operation of the calibration apparatus for confirming whether the strength of the test signal is properly estimated will be described.

9 is a flowchart illustrating validity of an estimated test signal strength according to various embodiments of the present disclosure; 9 illustrates an operation of the calibration apparatus 200 . In FIG. 9 , it is assumed that the code difference between the first phase code and the second phase code corresponds to a phase difference of 90°, and the code difference between the second phase code and the third phase code corresponds to the phase difference. However, this is for convenience of description, and various embodiments of the present disclosure are not limited to a code difference of 90°.

Referring to FIG. 9 , in step 901 , the calibration apparatus estimates a first candidate value for the strength of the test signal based on the strength of the combined signal with respect to the first phase code and the strength of the combined signal with respect to the third phase code. do. For example, the first candidate value for the strength of the test signal may be estimated as in Equation 14 below:

는 테스트 신호에 대한 제1 후보 값, y₁은 제1 후보 코드에 대해 측정된 조합 신호의 세기, y₃은 제3 후보 코드에 대해 측정된 조합 신호의 세기,

은 기준 신호의 세기를 의미한다.From here,

is a first candidate value for the test signal, y ₁ is the strength of the combined signal measured for the first candidate code, y ₃ is the strength of the combined signal measured for the third candidate code,

is the strength of the reference signal.

In operation 903, the calibration apparatus estimates a second candidate value for the strength of the test signal based on the strength of the combined signal with respect to the first phase code and the strength of the combined signal with respect to the third phase code. For example, the second candidate value for the strength of the test signal may be estimated based on <Equation 1> and <Equation 2>.

In operation 905 , the calibration apparatus estimates a third candidate value for the strength of the test signal based on the strength of the combined signal with respect to the second phase code and the strength of the combined signal with respect to the third phase code. For example, the third candidate value for the strength of the test signal may be estimated based on Equations 4 and 5.

In step 907, the calibration apparatus determines whether a condition related to the estimated candidate values is satisfied. For example, the condition related to the candidate values may include a first condition that a difference between the estimated candidate values is equal to or less than a threshold value X ₃ . As another example, the condition related to the candidate values may include a second condition that a difference between the respective estimated candidate values and the intensity of the reference signal is equal to or less than a threshold value X ₄ . The condition related to the candidate values may include at least one of the above-described first condition and second condition. The threshold value X ₃ and the threshold value X- ₄ may be determined based on a gain and/or desired performance designed for each RF chain. For example, if each RF chain is designed to have a gain of 30 dBm, the threshold value X ₃ may be 5 dB, and the threshold value X ₄ may be 7 dB. The above-described values of X ₃ and X--- ₄ are exemplary, and various modifications are possible. Also, the threshold values X ₃ and X-- ₄ may be preset values.

When the condition related to the candidate values is satisfied, in step 909 , the calibration apparatus estimates candidate codes for the calibration code of the target RF chain based on the strength of the combined signal with respect to the phase codes. For example, the calibration apparatus may estimate candidate codes according to <Equation 1> to <Equation 6>.

When the condition related to the candidate values is not satisfied, the calibration apparatus terminates the present algorithm. As another example, the calibration apparatus may return to step 901 to re-estimate candidate values for the strength of the test signal or measure the strength of the combination signal with respect to the phase codes again.

According to various embodiments of the present disclosure, the calibration apparatus may estimate the plurality of candidate codes for the calibration code of the target RF chain by measuring the strength of the combined signal with respect to the plurality of phase codes. Since the candidate code cannot be properly estimated when the signal strength measurement is incorrect, the calibration apparatus may inversely determine whether the signal strength measurement is incorrect based on the validity of the estimated candidate codes.

10A and 10B illustrate other examples of calibration results according to various embodiments of the present disclosure. In graphs 1010 and 1020, the horizontal axis indicates the phase code set in the target RF chain, and the vertical axis indicates the strength of the combined signal.

Referring to FIG. 10A , in graph 1010, a function of the combined signal strength of the first candidate code and the function of the combined signal strength of the second candidate code are similar. In other words, the first candidate code and the second candidate code are similar, and the code difference between the first candidate code and the second candidate code may be relatively small (eg, within a 2-code difference). In this case, it may be determined that the first candidate code and the second candidate code are properly estimated.

Referring to FIG. 10B , in the graph 1020, the function of the combined signal strength for the first candidate code and the function of the combined signal strength for the second candidate code are significantly different. In other words, the first candidate code and the second candidate code are significantly different, and the code difference between the first candidate code and the second candidate code may be relatively large (eg, a 3-code difference). In this case, it may be determined that the first candidate code and the second candidate code are not properly estimated.

According to various embodiments of the present disclosure, when an RF chain fails or a phase shifter paging fails, a candidate code may be incorrectly estimated. As another example, when the signal strength (eg, the strength of the combined signal, the strength of the reference signal) is measured incorrectly, the phase code set in the target RF chain is incorrectly controlled, or the measurement setting is incorrect, the candidate code may be incorrectly estimated. .

When the calibration apparatus sets a calibration code determined from among erroneously estimated candidate codes to a target RF chain, a beam in a feature direction may not be properly generated by the phased array antenna. Accordingly, an operation of the calibration apparatus is required to check whether the candidate code is properly estimated, which will be described in more detail with reference to FIG. 11 below.

11 is a flowchart for confirming validity of an estimated candidate code according to various embodiments of the present disclosure. 11 illustrates an operation of the calibration device 200 .

Referring to FIG. 11 , in step 1101 , the calibration apparatus determines whether a code difference between a first candidate code and a second candidate code is equal to or less than a threshold value X ₅ . As another example, the calibration apparatus may determine whether a phase difference between a phase corresponding to the first candidate code and a phase corresponding to the second candidate code is equal to or less than a threshold value X ₅ . According to various embodiments of the present disclosure, the threshold value X ₅ may be set to guarantee the performance of the phased array antenna after calibration. For example, if the threshold X ₅ − corresponds to 60°, the phase error of the RF chain (that is, the phase corresponding to the code difference between the calibration code of the RF chain and the phase code currently set in the RF chain) is up to 60° and the direction or pattern of the beam formed by the phased array antenna may be severely distorted. Thus, the threshold X ₅ - may correspond to an angle less than 60° (eg 45°). The above-described value of X ₅ is exemplary, and various modifications are possible. Also, the threshold value X ₅ may be a preset value.

When the code difference between the first candidate code and the second candidate code is equal to or less than the threshold value X ₅ , in step 1103, the calibration apparatus determines one of the first candidate code and the second candidate code as the calibration code. For example, the calibration apparatus may compare an error with respect to the first candidate code and an error with respect to the second candidate code, and determine a candidate code having a smaller error as the calibration code.

When the code difference between the first candidate code and the second candidate code exceeds the threshold value X ₅ , the calibration apparatus terminates the present algorithm. As another example, after re-estimating the first candidate code and the second candidate code or measuring the strength of the combined signal with respect to the phase codes again, the calibration apparatus may perform operation 1101 and subsequent operations again.

12 is a diagram 1200 illustrating a relationship between validity of an estimated strength of a test signal and validity of an estimated candidate code according to various embodiments of the present disclosure.

Referring to FIG. 12 , the validity of the estimated strength of the test signal may be a necessary condition for the validity of the estimated candidate code. In other words, in order for the estimated candidate code to be valid, it is required that the estimated strength of the test signal is valid. When the estimated strength of the test signal is not valid, the estimated candidate code may also be invalid.

In the above-described examples, the calibration apparatus estimates the strength of the test signal and the candidate code, and determines whether the estimated strength of the test signal and the candidate code are valid. Also, the calibration apparatus according to various embodiments of the present disclosure may measure the intensity of the reference signal and determine whether the measured intensity of the reference signal is appropriate. An operation of the calibration apparatus for determining the validity of the measured strength of the reference signal will be described in more detail below with reference to FIG. 13 .

13 is a flowchart for determining the validity of the measured strength of a reference signal according to various embodiments of the present disclosure. 13 illustrates an operation of the calibration apparatus 200 .

Referring to FIG. 13 , in step 1301 , the calibration apparatus measures the intensity of the reference signal. The calibration apparatus may measure the strength of the reference signal by turning on only the reference RF chain and turning off the remaining RF chains of the phased array antenna. At this time, an arbitrary phase code may be set in the reference RF chain.

In operation 1303 , the calibration apparatus determines whether the measured intensity of the reference signal is between a threshold value X ₁ and a threshold value X ₂ . Threshold X ₁ and Threshold X ₂ - may be determined based on the designed gain, maximum gain offset and/or desired performance for each RF chain. For example, if each RF chain is designed to have a gain of 30 dBm, and the maximum gain offset is 3 dB, the strength of the reference signal should be between 27 dBm and 33 dBm. Accordingly, in this case, the threshold value X ₁ may be 27 dBm, and the threshold value X ₂ may be 33 dBm. The above-described values of X ₁ and X ₂ are exemplary, and various modifications are possible. Also, the threshold values X ₁ and X-- ₂ - may be preset values.

When the measured strength of the reference signal is between the threshold value X ₁ and the threshold value X ₂ , in step 1305, the calibration device measures the strength of the combined signal for the phase codes set in the target RF chain based on the reference signal do. In other words, when it is determined that the measured strength of the reference signal is reasonable, the calibration apparatus may measure the strength of a signal of a combination of the reference signal and the test signal with respect to the phase codes.

If the measured strength of the reference signal is not between the threshold value X ₁ and the threshold value X ₂ , the calibration apparatus terminates the present algorithm. As another example, the calibration apparatus may return to step 1301 and measure the strength of the reference signal again.

14 is a flowchart illustrating overall operations of a calibration apparatus according to various embodiments of the present disclosure. Show the flow chart. 14 illustrates an operation of the calibration apparatus 200 .

Referring to FIG. 14 , in step 1401 , the calibration apparatus measures the intensity of the reference signal. The calibration apparatus may measure the strength of the reference signal by turning on only the reference RF chain and turning off the remaining RF chains of the phased array antenna. At this time, an arbitrary phase code may be set in the reference RF chain.

In operation 1403 , the calibration apparatus determines whether the measured intensity of the reference signal is between a threshold value X ₁ and a threshold value X ₂ . Threshold X ₁ and Threshold X ₂ - may be determined based on the designed gain, maximum gain offset and/or desired performance for each RF chain. As another example, the threshold value X ₁ and the threshold value X ₂ - may be predetermined values.

If the measured strength of the reference signal is between the threshold value X ₁ and the threshold value X ₂ , in step 1405 , the calibration device turns on the target RF chain. When the strength of the measured reference signal is reasonable, the calibration device turns on the target RF chain (eg, supplies a bias current and/or voltage) to calibrate the target RF chain based on the reference signal.

If the measured strength of the reference signal is between the threshold value X ₁ and the threshold value X ₂ , in operation 1435 , the calibration apparatus determines that an error code (ie, an incorrect calibration code) is to be estimated. As another example, the calibration apparatus may return to step 1401 and measure the strength of the reference signal again.

In operation 1407, the calibration apparatus sets respective phase codes in the target RF chain, and measures the strength of the combined signal for each phase code. For example, the calibration apparatus may measure the strength of a combined signal with respect to the first phase code by setting the first phase code in the target RF chain. The calibration apparatus may measure the strength of a combined signal with respect to the second phase code by setting the second phase code in the target RF chain. By setting the third phase code in the target RF chain, the strength of the combined signal with respect to the third phase code may be measured. For convenience of description, it is assumed that the code difference between the first phase code and the second phase code corresponds to 90°, and the code difference between the second phase code and the third phase code corresponds to 90°. However, this is exemplary, and various modifications to the code difference are possible.

In operation 1409, the calibration apparatus estimates a candidate value for the strength of the test signal. For example, the calibration device according to <Equation 14>, <Equation 1>, <Equation 2>, <Equation 4> and/or <Equation 5>, the intensity of the combined signal measured in step 1407 Candidate values for the strength of the test signal may be estimated using these values.

In operation 1411 , the calibration apparatus determines whether a difference between estimated candidate values is equal to or less than a threshold value X ₃ . The threshold X ₃ may be determined based on the desired performance and/or the gain designed for each RF chain. As another example, the threshold value X ₃ may be a predetermined value. If the difference between the estimated candidate values is not equal to or less than the threshold value X ₃ , in step 1435 , the calibration apparatus determines that an error code is to be estimated. As another example, the calibration apparatus may return to operation 1409 to re-estimate candidate values for the strength of the test signal, or return to operation 1407 to measure the strength of the combined signal with respect to the phase codes again.

When the difference between the estimated candidate values is equal to or less than the threshold X ₃ , in operation 1413 , the calibration apparatus determines whether a difference between the estimated candidate value and the measured intensity of the reference signal is equal to or less than the threshold X ₄ . The threshold X ₄ may be determined based on the desired performance and/or the gain designed for each RF chain. As another example, the threshold value X ₄ may be a predetermined value. When the difference between the intensity period of the estimated candidate value and the measured reference signal is not equal to or less than the threshold value X ₄ , in operation 1435 , the calibration apparatus determines that an error code is to be estimated. As another example, the calibration apparatus may return to operation 1409 to re-estimate candidate values for the strength of the test signal, or return to operation 1407 to measure the strength of the combined signal with respect to the phase codes again.

If the difference between the intensity period of the estimated candidate value and the measured reference signal is equal to or less than the threshold value X ₄ , in operation 1415 , the calibration apparatus estimates candidate codes for the calibration code of the target RF chain. The calibration apparatus may determine a phase difference between a phase corresponding to a phase code and a reference phase and a phase state of the phase difference based on the strength of a combined signal for the phase codes, and a candidate based on the phase difference and the phase state of the phase difference code can be inferred. For example, the calibration apparatus may estimate the first candidate code based on the first phase code and the second phase code, and may estimate the second candidate code based on the second phase code and the third phase code. .

In step 1417 , the calibration apparatus determines whether a code difference between candidate codes is equal to or less than a threshold value X ₅ . The threshold value X ₅ may be set to guarantee the performance of the phased array antenna after calibration. Alternatively, the threshold value X ₅ may be a preset value. For example, the calibration apparatus may determine whether a code difference between the first candidate code and the second candidate code is equal to or less than a threshold value X ₅ . As another example, the calibration apparatus may determine whether a phase difference between a phase corresponding to the first candidate code and a phase corresponding to the second candidate code is equal to or less than a threshold value X ₅ . When the code difference between the candidate codes is not equal to or less than the threshold value X ₅ , in operation 1435 , the calibration apparatus may determine that an error code is to be estimated. As another example, the calibration apparatus may return to step 1415 to re-estimate the candidate codes, or return to step 1407 to measure the strength of the combined signal with respect to the phase codes again.

If the code difference between the candidate codes is equal to or less than the threshold X ₅ , in operation 1421 , the calibration apparatus determines a function of the combined signal strength for each of the candidate codes. For example, the calibration apparatus may generate a function of the combined signal strength for the first candidate code and generate a function of the combined signal strength for the second candidate code.

In step 1423, the calibration device determines the signal strength vectors. For example, the calibration apparatus may include a measured signal strength vector for the phase codes (ie, a measured signal strength vector) and an estimated signal strength vector for the phase codes under the condition that the first candidate code corresponds to a reference phase. (ie, the signal strength vector associated with the first candidate code) and the estimated signal strength vector for the phase codes under the condition that the second candidate code corresponds to the reference phase (ie, the signal strength vector associated with the second candidate code) can be decided To determine the signal strength vector associated with the first candidate code and the signal strength vector associated with the second candidate code, a function of the combined signal strength determined in operation 1421 may be used.

In operation 1425 , the calibration apparatus determines whether an error with respect to the first candidate code (ie, LSE _{can1 ) is smaller than an error with respect to the second candidate code (ie, LSE can2 )} . In other words, the calibration apparatus may compare the error with respect to the first candidate code and the error with respect to the second candidate code.

When the error with respect to the first candidate code (ie, LSE _{can1 ) is smaller than the error with respect to the second candidate code (ie, LSE can2 )} , in step 1427 , the calibration apparatus determines the first candidate code as the calibration code. If the error with respect to the first candidate code (ie, LSE _{can1 ) is not smaller than the error with respect to the second candidate code (ie, LSE can2 )} , in step 1429 , the calibration apparatus determines the second candidate code as the calibration code. In other words, the calibration apparatus may determine a candidate code having a smaller error among the estimated candidate codes as the calibration code.

In step 1431, the calibration device determines whether all RF chains have been calibrated. In other words, the calibration apparatus determines whether there is at least one uncalibrated RF chain among all the RF chains of the phased array antenna. When all RF chains are calibrated, the calibration device ends this algorithm. If all RF chains are not calibrated, in step 1433, the calibration apparatus changes the target RF chain, returns to step 1405, and performs steps 1405 and subsequent steps for the changed target RF chain. That is, the calibration apparatus selects an RF chain on which calibration is not performed, and performs operations for calibrating the selected RF chain.

In the above-described examples, two candidate codes (eg, a first candidate code and a second candidate code) were considered to determine the calibration code. However, according to various embodiments of the present disclosure, an additional candidate code may be considered in addition to the two candidate codes to determine the calibration code. This additional candidate code may be estimated based on the strength of the combined signal measured for the phase codes, similar to the estimation method of the first candidate code and the second candidate code. As another example, the additional candidate code may be derived from the first candidate code and the second candidate code. For example, the additional candidate code may be determined as a phase code within a threshold code difference from the first candidate code and/or the second candidate code. The calibration apparatus may more accurately determine the calibration code by considering an error with respect to the additional candidate code.

Hereinafter, a method of determining a calibration code based on an error with respect to an additional candidate code is described in FIG. 15 .

15 is a flowchart for determining a calibration code in consideration of an additional candidate code according to various embodiments of the present disclosure. 15 illustrates an operation of the calibration apparatus 200 .

Referring to FIG. 15 , in step 1501 , the calibration apparatus determines an additional candidate code within a threshold code difference from the candidate code. As another example, the calibration apparatus may determine an additional candidate code corresponding to a phase within a threshold phase from a phase corresponding to the candidate code. According to various embodiments of the present disclosure, the threshold code difference may be a threshold value X ₅ , and the threshold phase may be a phase (eg, 45°) corresponding to the threshold value X ₅ . For example, when the number of possible phase codes of the target RF chain is 16, one code difference corresponds to 360/16=22.5°, and thus, when the critical phase is 45°, the critical code difference can be two code differences. The values of the critical code difference and the critical phase described above are exemplary, and various modifications are possible.

In step 1503, the calibration apparatus determines a calibration code based on an error with respect to the additional candidate code. The calibration apparatus determines an error between the intensity of the combined signal estimated for the phase codes and the intensity of the combined signal measured for the phase codes under the condition that the additional candidate code corresponds to the reference phase (ie, the error with respect to the additional candidate code) can be decided The calibration apparatus may determine the candidate code having the smallest error as the calibration code by comparing the error with respect to the additional candidate code and the error with respect to other candidate codes.

16 is a graph illustrating a function of a combined signal strength for an additional candidate code according to various embodiments of the present disclosure. In the graph 1600 of FIG. 16 , the horizontal axis indicates a phase corresponding to the phase code set in the target RF chain, and the vertical axis indicates the strength of the combined signal.

Referring to FIG. 16 , the first additional candidate code may be derived from the first candidate code. For example, the first additional candidate code may be a code corresponding to a phase smaller than a phase of the first candidate code within a threshold code difference from the first candidate code. Thus, in graph 1600, a function of the strength of the combined signal for the possible phase codes of the target RF chain under the condition that the first additional candidate code corresponds to the reference phase (ie, a function of the strength of the combined signal for the first additional candidate code) ) is adjacent to the function of the combined signal strength for the first candidate code, and is located to the left of the function of the combined signal strength for the first candidate code.

Similarly, a second additional candidate code may be derived from the second candidate code. For example, the second additional candidate code may be a code corresponding to a phase greater than a phase of the second candidate code within a threshold code difference from the second candidate code. Thus, in graph 1600, a function of the combined signal strength for the possible phase codes of the target RF chain (ie, a function of the combined signal strength for the second additional candidate code) under the condition that the second additional candidate code corresponds to the reference phase. ) is adjacent to the function of the combined signal strength for the second candidate code, and is located to the right of the function of the combined signal strength for the second candidate code.

The calibration apparatus may determine a signal strength vector associated with the first additional candidate code based on a function of the combined signal strength for the first additional candidate code, and based on the signal strength vector associated with the first additional candidate code, the first additional candidate code. Errors for additional candidate codes can be determined. Similarly, the calibration apparatus may determine an error for the second additional candidate code. The calibration apparatus may more accurately determine a calibration code by considering not only errors with respect to candidate codes but also errors with respect to additional candidate codes.

17 illustrates phase codes set in RF chains as a result of calibration according to various embodiments of the present disclosure.

In FIG. 17 , a calibration code determined by considering all possible phase codes of a target RF chain may be regarded as a correct calibration code. Referring to Table 1740, when the first candidate code is considered, an error code can be estimated for the RF chain 3, and when the second candidate code is considered, an error code can be estimated for the RF chain 12. On the other hand, when the first candidate code and the second candidate code are considered (that is, when a candidate code having a small error is selected in consideration of errors for the two candidate codes), no error code is estimated for any RF chain and , the correct calibration code can be estimated for all RF chains.

Graph 1710 shows the relationship between the intensity of the combined signal and the phase code set in the target RF chain when RF chain 3 is the target RF chain. Referring to graph 1710, the combined signal strength measured for the possible phase codes of the target RF chain (ie, RF chain 3) is similar to a function of the combined signal strength for the second candidate code, but for the first candidate code. It is not similar to a function of the combined signal strength for In other words, the calibration code (code 4) is the same as the second candidate code (code 4), but not the same as the first candidate code (code 3). As in this example, since the first candidate code is not the same as the calibration code, when only the first candidate code is considered, an incorrect phase code in some RF chains (eg, RF chain 3) may be estimated as the calibration code. .

Graph 1720 shows the relationship between the intensity of the phase code set in the target RF chain and the combined signal when the RF chain 10 is the target RF chain. Referring to graph 1720, the combined signal strength measured for possible phase codes of the target RF chain (ie, RF chain 10) is a function of the combined signal strength for the first candidate code and the combination for the second candidate code. It is analogous to a function of signal strength. In other words, the calibration code (code 4) is the same as the first candidate code (code 4) and the second candidate code (code 4). As in this example, even if only one candidate code (eg, the first candidate code or the second candidate code) is considered, the calibration code of the RF chain (eg, RF chain 10) can be correctly estimated.

Graph 1730 shows the relationship between the intensity of the phase code set in the target RF chain and the combined signal when the RF chain 12 is the target RF chain. Referring to graph 1730, the combined signal strength measured for the possible phase codes of the target RF chain (ie, RF chain 12) is similar to a function of the combined signal strength for the first candidate code, but for the second candidate code. It is not similar to a function of the combined signal strength for In other words, the calibration code (code 2) is the same as the first candidate code (code 2), but is not the same as the second candidate code (code 0). As in this example, since the second candidate code is not the same as the calibration code, when only the second candidate code is considered, an incorrect phase code in some RF chains (eg, RF chain 12) may be estimated as the calibration code. .

As in the above example, by estimating a plurality of candidate codes in consideration of at least three phase codes and estimating a calibration code based on an error for each candidate code, the calibration apparatus can more accurately estimate the calibration code. .

18 illustrates a type of calibration according to various embodiments of the present disclosure.

Referring to FIG. 18 , the type of calibration may include at least one of a factory calibration 1810, an online calibration 1820, and a self calibration 1830.

Factory calibration 1810 refers to calibration when the calibration device calibrates an external phased array antenna. In this case, the calibration device may be a measuring instrument 1813 . For example, the instrument 1813 may have the configuration of the calibration device 200 shown in FIG. 2A, and the phased array antenna included in the base station/terminal 1811 may be calibrated using at least one of the controller 210, the transceiver 220, and the reference antenna 230. have.

In the online calibration 1820, the calibration device communicates with another communication device through a wireless channel to obtain a measurement value (eg, the strength of a combined signal, the strength of a reference signal and/or a test signal), and uses the measurement value to perform a phase array It means calibration in the case of calibrating the antenna. In this case, the calibration device may be a communication device (eg, a base station 1821, a terminal 1823), and the phased array antenna for calibration may be a phased array antenna included in the corresponding communication device. For example, the base station 1821 and the terminal 1823 may perform communication through a wireless channel to obtain a measurement value, and calibrate the phased array antenna based on the measurement value. As another example, the base station 1821 may perform communication with another base station through a wireless backhaul (eg, wireless backhaul 1825 and/or wireless backhaul 1827) to obtain a measurement value, and calibrate the phased array antenna based on the measurement value. For the online calibration 1820, the base station 1821 and/or the terminal 1823 may have the configuration of the calibration device 200 shown in FIG. 2B, and a phased arrangement using at least one of the communication unit 250, the storage unit 260, the control unit 270, and the feedback loop 280 The antenna can be calibrated.

According to various embodiments of the present disclosure, a resource (hereinafter, referred to as a 'calibration resource') for online calibration 1820 may be defined. For example, the calibration resource may include a time slot. The communication devices may transmit or receive a signal (eg, a combination signal, a reference signal, and/or a test signal) for obtaining a measurement value by using a calibration resource for the online calibration 1820 . The calibration resource may be pre-configured, configured by higher layer signaling, or dynamically allocated by physical layer signaling (eg, downlink control information (DCI)).

Self-Calibration 1830 provides calibration when the calibration device self-calibrates the phased array antenna included in the calibration device without the aid of another device (e.g., with the aid of an external instrument or without transmitting/receiving signals to/from another device). it means. In this case, the calibration apparatus may acquire a measurement value by itself, and may calibrate its phased array antenna based on the measurement value. According to various embodiments of the present disclosure, a calibration device that performs self-calibration 1830 may be a communication device such as a base station or a terminal. For the self-calibration 1830, the calibration device may include at least one of an internal meter 1831 and a beamforming calibration network 1833. The internal instrument 1831 may generate a control signal for the measurement, measure the strength of signals (eg, a combination signal, a test signal, and/or a reference signal) to obtain a measurement value, and generate a calibration code based on the measurement value. can decide For example, the internal meter 1831 may be a part of the controller 270 . The beamforming calibration network 1833 may include a circuit (eg, a feedback loop 280 ) for transmitting and processing a signal for measurement. For self-calibration 1830, the calibration device may have the configuration of the calibration device 200 shown in FIG. 2B, and may calibrate the phased array antenna using at least one of the communication unit 250, the storage unit 260, the control unit 270, and the feedback loop 280. have.

19A and 19B illustrate signal exchange between communication devices for online calibration according to various embodiments of the present disclosure.

Referring to FIG. 19A , a base station 1910 transmits signals (eg, a combination signal, a reference signal, and/or a test signal) to a terminal 1920 through a wireless access channel, and transmits signals measured by the terminal 1920. Information on strength may be received from the terminal 1920. The base station 1910 may determine a calibration code of a target RF chain for transmission based on the strength of the measured signals, and may calibrate the phased array antenna of the base station 1910 . In addition, the base station 1910 may receive a calibration signal from the terminal 1920 through a wireless access channel, and measure the strength of the combined signal, the reference signal, and/or the test signal based on the calibration signal. The base station 1910 may determine the calibration code of the target RF chain based on the strength of the measured signals, determine the calibration code of the target RF chain for reception, and calibrate the phased array antenna of the base station 1910 .

The terminal 1920 transmits signals (eg, a combined signal, a reference signal, and/or a test signal) to the base station 1910 through a radio access channel, and information about the strength of signals measured by the base station 1910 can be received from the base station 1910 have. The terminal 1920 may determine a calibration code of the target RF chain for transmission based on the strength of the measured signals, and may calibrate the phased array antenna of the terminal 1920. FIG. In addition, the terminal 1920 may receive a calibration signal from the base station 1910 through a radio access channel, and may measure the strength of the combination signal, the reference signal, and/or the test signal based on the calibration signal. The terminal 1920 may determine a calibration code of a target RF chain for reception based on the strength of the measured signals, and may calibrate the phased array antenna of the terminal 1920. FIG.

Referring to FIG. 19B , the base station 1930 transmits signals (eg, a combination signal, a reference signal, and/or a test signal) to the base station 1940 through a wireless backhaul channel, and Strength information may be received from the base station 1940. The base station 1930 may determine a calibration code of the target RF chain for transmission based on the strength of the measured signals, and may calibrate the phased array antenna of the base station 1930. FIG. In addition, the base station 1930 may receive a calibration signal from the base station 1940 through a radio access channel, and measure the strength of the combination signal, the reference signal, and/or the test signal based on the calibration signal. The base station 1930 may determine a calibration code of a target RF chain for reception based on the strength of the measured signals, and may calibrate the phased array antenna of the base station 1930. FIG.

In the examples of FIGS. 19A and 19B , a signal transmitted or received through a radio access channel or a radio backhaul channel may be transmitted or received using a calibration resource.

20 is a flowchart for online calibration according to various embodiments of the present disclosure. 20 illustrates an operation of the calibration apparatus 200 .

Referring to FIG. 20 , in step 2001, the calibration device sets each of the phase codes in the target RF chain, and transmits a combined signal for each phase code to another communication device. The combined signal may be transmitted through a radio access channel and/or a radio backhaul channel, and may be transmitted using a calibration resource. The calibration device may transmit a reference signal and/or a test signal to another communication device in addition to the combination signal.

In step 2003, the calibration device receives information about the strength of the combined signal measured by the other device from the other communication device. The calibration device may receive information about the strength of another signal (eg, a reference signal and/or a test signal) from another communication device in addition to information about the strength of the combined signal.

In step 2005, the calibration apparatus estimates at least one candidate code for the calibration code of the target RF chain based on the strength of the combined signal. In other words, the calibration device may acquire measurement values for calibrating the phased array antenna by communicating with another communication device.

Once the phased array antenna is calibrated, the phased array antenna can radiate or beam electromagnetic waves in a desired direction. Hereinafter, operations for forming a beam in a specific direction after calibration are described with reference to FIG. 21 .

21 is a flowchart for forming a beam in a specific direction after calibration according to various embodiments of the present disclosure. 21 exemplifies the operation of the calibration device 200 . In this example, the calibration device 200 may be a communication device such as a base station and/or a terminal.

Referring to FIG. 21 , in step 2101, the calibration apparatus determines a direction of a beam for transmitting and receiving a signal. For example, the calibration apparatus may determine the direction of the transmit beam and/or the direction of the receive beam through beam training or beam sweeping with another communication apparatus.

In step 2103, the calibration device determines the phase code of the RF chain corresponding to the determined direction. According to various embodiments of the present disclosure, when a calibration code is set in all RF chains of the phased array antenna, signals related to the RF chains may all have the same phase and may propagate in a specific direction as a whole. When a calibration code is set in all RF chains of the phased array antenna, the propagation direction of signals related to the RF chains may be referred to as a 'reference direction'. The calibration apparatus may determine an angular difference between a desired signal direction and a reference direction, and may determine an amount of phase change and a code difference required for each RF chain for the determined angular difference. Here, the amount of phase change and the code difference required for each RF chain may be different for each RF chain. The calibration apparatus may determine a phase code to be set in each RF chain in order to form a beam in a desired direction by applying a code difference determined with respect to the calibration code of each RF chain. In other words, for each RF chain, the calibration apparatus may determine a phase code such that a code difference (or a phase change amount and/or a phase difference corresponding to the code difference) between the phase code and the calibration code corresponds to a desired direction.

In operation 2105, the calibration apparatus sets the determined phase code in the RF chain, and transmits and receives a signal through the beam in the determined direction. RF chains in which a phase code corresponding to the determined direction is set as a whole forms a plane wave, and signals related to the RF chains may be propagated in a desired direction as a whole.

Methods according to the embodiments described in the claims or specifications of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium are configured to be executable by one or more processors in an electronic device (device). One or more programs include instructions for causing an electronic device to execute methods according to embodiments described in a claim or specification of the present disclosure.

Such programs (software modules, software) include random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable ROM (electrically erasable programmable read only memory, EEPROM), magnetic disc storage device, compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other It may be stored in an optical storage device or a magnetic cassette. Alternatively, it may be stored in a memory composed of a combination of some or all thereof. In addition, each configuration memory may be included in plurality.

In addition, the program is transmitted through a communication network consisting of a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), or a storage area network (SAN), or a combination thereof. It may be stored on an attachable storage device that can be accessed. Such a storage device may be connected to a device implementing an embodiment of the present disclosure through an external port. In addition, a separate storage device on the communication network may be connected to the device implementing the embodiment of the present disclosure.

In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed in the singular or plural according to the specific embodiments presented. However, the singular or plural expression is appropriately selected for the context presented for convenience of description, and the present disclosure is not limited to the singular or plural component, and even if the component is expressed in plural, it is composed of a singular or singular. Even an expressed component may be composed of a plurality of components.

Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, various modifications are possible without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments and should be defined by the claims described below as well as the claims and equivalents.

Claims (20)

A method for calibrating a phased array antenna, comprising:
A process of estimating at least one candidate code for a calibration code of a target RF chain by setting phase codes in a target RF (radio frequency) chain;
determining the calibration code based on the intensity of the first combined signal estimated with respect to the phase codes and the intensity of the second combined signal measured with respect to the phase codes;
setting the calibration code in the target RF chain to calibrate the target RF chain,
The first combined signal and the second combined signal include a combination of signals associated with the target RF chain and a reference RF chain.
The method according to claim 1, wherein the phase codes include a first phase code, a second phase code and a second phase code, the at least one candidate code includes a first candidate code and a second candidate code;
The process of estimating the at least one candidate code includes:
a first phase difference between a phase corresponding to the first phase code and a reference phase is determined based on the strength of the combined signal measured with respect to the first phase code, and the strength of the combined signal measured with respect to the second phase code determining a second phase difference between a phase corresponding to the second phase code and the reference phase based on
The phase state of the first phase difference is determined based on the strength of the combined signal measured with respect to the second phase code, and the phase of the second phase difference is determined based on the strength of the combined signal measured with respect to the third phase code. the process of determining the state, and
The first candidate code is estimated based on the first phase difference and the phase state of the first phase difference, and the second candidate code is estimated based on the second phase difference and the phase state of the second phase difference How to include a process.
The method according to claim 2, wherein a phase difference between the phase corresponding to the first phase code and the phase corresponding to the second phase code is 90°,
A phase difference between a phase corresponding to the second phase code and a phase corresponding to the third phase code is 90°.
The method according to claim 2, The process of determining the calibration code,
determining a first error between the intensity of the combined signal estimated for the phase codes and the intensity of the second combined signal under the condition that the first candidate code corresponds to the reference phase;
determining a second error between the intensity of the combined signal estimated for the phase codes and the intensity of the second combined signal under the condition that the second candidate code corresponds to the reference phase;
determining the first candidate code as the calibration code when the first error is smaller than the second error;
and determining the second candidate code as the calibration code when the second error is smaller than the first error.
The first candidate for the strength of a signal associated with the target RF chain according to claim 2, based on the strength of the combined signal measured for the first phase code and the strength of the combined signal measured for the third phase code. the process of estimating the value, and
The process of estimating a second candidate value for the strength of the signal associated with the target RF chain based on the strength of the combined signal measured with respect to the first phase code and the strength of the combined signal measured with respect to the second phase code class,
a difference between the first candidate value and the second candidate value is equal to or less than a third threshold, and a difference between at least one of the first candidate value and the second candidate value and a difference in intensity between the signal associated with the reference RF chain is a fourth threshold Further comprising the process of determining whether a condition of less than or equal to a value is satisfied;
The estimating of the first candidate code and the second candidate code includes estimating the first candidate code and the second candidate code when the condition is satisfied.
The method according to claim 2, further comprising: determining whether a code difference between the first candidate code and the second candidate code is equal to or less than a fifth threshold,
The determining of the calibration code includes determining one of the first candidate code and the second candidate code as a calibration code when the code difference is equal to or less than the fifth threshold value.
The method according to claim 1, Measuring the strength of a signal related to the reference RF chain;
determining whether the measured signal strength is between a first threshold value and a second threshold value;
and measuring the strength of the second combined signal based on a signal related to the reference RF chain when the measured signal strength is between the first threshold value and the second threshold value.
The method according to claim 1, further comprising the steps of: determining an additional candidate code within a threshold code difference from the at least one candidate code;
Further comprising the step of determining an error between the intensity of the combined signal estimated for the phase codes and the intensity of the second combined signal when the additional candidate code is set in the reference RF chain,
The determining of the calibration code may include determining the calibration code based on the determined errors.
The method according to claim 1, transmitting the second combined signal to another communication device;
Further comprising the step of receiving information about the strength of the second combination signal measured by the other communication device from the other communication device,
The at least one candidate code is estimated based on information about the strength of the received second combined signal.
The method according to claim 1, further comprising: determining a direction of a beam for transmitting and receiving a signal;
determining the phase code of the target RF chain such that a code difference between the phase code and the calibration code corresponds to the determined direction;
Setting the phase code in the target RF chain, the method further comprising the step of transmitting and receiving the signal through the beam in the direction.
An apparatus for calibrating a phased array antenna, comprising:
Set phase codes in a target RF (radio frequency) chain to estimate at least one candidate code for a calibration code of the target RF chain,
determine the calibration code based on the intensity of the first combined signal estimated with respect to the phase codes and the intensity of the second combined signal measured with respect to the phase codes;
a control unit configured to calibrate the target RF chain by setting the calibration code to the target RF chain;
The first combined signal and the second combined signal include a combination of signals associated with the target RF chain and the reference RF chain.
12. The method of claim 11, wherein the phase codes include a first phase code, a second phase code and a second phase code, the at least one candidate code includes a first candidate code and a second candidate code;
The control unit is
a first phase difference between a phase corresponding to the first phase code and a reference phase is determined based on the strength of the combined signal measured with respect to the first phase code, and the strength of the combined signal measured with respect to the second phase code determining a second phase difference between a phase corresponding to the second phase code and the reference phase based on
The phase state of the first phase difference is determined based on the strength of the combined signal measured with respect to the second phase code, and the phase of the second phase difference is determined based on the strength of the combined signal measured with respect to the third phase code. determine the status,
The first candidate code is estimated based on the first phase difference and the phase state of the first phase difference, and the second candidate code is estimated based on the second phase difference and the phase state of the second phase difference device to do.
The method according to claim 12, wherein a phase difference between the phase corresponding to the first phase code and the phase corresponding to the second phase code is 90°,
A phase difference between a phase corresponding to the second phase code and a phase corresponding to the third phase code is 90°.
The method according to claim 12, wherein the control unit,
determining a first error between an intensity of a combined signal estimated for the phase codes and an intensity of the second combined signal under the condition that the first candidate code corresponds to the reference phase;
determining a second error between the intensity of the combined signal estimated for the phase codes and the intensity of the second combined signal under the condition that the second candidate code corresponds to the reference phase;
when the first error is smaller than the second error, determining the first candidate code as the calibration code;
When the second error is smaller than the first error, the apparatus determines the second candidate code as the calibration code.
The method according to claim 12, wherein the control unit,
estimating a first candidate value for the strength of a signal associated with the target RF chain based on the strength of the combined signal measured with respect to the first phase code and the strength of the combined signal measured with respect to the third phase code;
estimating a second candidate value for the strength of a signal associated with the target RF chain based on the strength of the combined signal measured with respect to the first phase code and the strength of the combined signal measured with respect to the second phase code;
a difference between the first candidate value and the second candidate value is equal to or less than a third threshold, and a difference between at least one of the first candidate value and the second candidate value and a difference in intensity between the signal associated with the reference RF chain is a fourth threshold Determines whether the condition of less than or equal to the value is satisfied,
An apparatus for estimating the first candidate code and the second candidate code when the condition is satisfied.
The method of claim 12, wherein the control unit determines whether a code difference between the first candidate code and the second candidate code is equal to or less than a fifth threshold,
When the code difference is equal to or less than the fifth threshold, determining one of the first candidate code and the second candidate code as a calibration code.
The method according to claim 11, wherein the control unit,
Measuring the strength of a signal associated with the reference RF chain,
determining whether the measured signal strength is between a first threshold value and a second threshold value;
When the strength of the measured signal is between the first threshold value and the second threshold value, the apparatus for measuring the strength of the second combined signal based on the signal related to the reference RF chain.
The method according to claim 11, wherein the control unit,
determine an additional candidate code within a threshold code difference from the at least one candidate code;
determining an error between the intensity of the combined signal estimated for the phase codes and the intensity of the second combined signal when the additional candidate code is set in the reference RF chain;
An apparatus for determining the calibration code based on the determined errors.
The method according to claim 11, further comprising a communication unit for transmitting the second combined signal to another communication device, and receiving information about the strength of the second combined signal measured by the other communication device from the other communication device,
The at least one candidate code is estimated based on information about the strength of the received second combined signal.
The method according to claim 11, wherein the control unit determines a direction of a beam for transmitting and receiving a signal, and determines the phase code of the target RF chain that causes a code difference between a phase code and the calibration code to correspond to the determined direction,
and a communication unit configured to transmit and receive the signal through the beam in the direction by setting the phase code in the target RF chain.

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