Calibration circuit and calibration method

Abstract

The embodiment of the invention discloses a calibration circuit and a calibration method, and the calibration circuit is internally provided with a baseband unit, M groups of radio frequency circuits connected with the baseband unit, a combiner which is configured to synthesize an output signal according to multiple paths of input signals, and a distributor which is configured to equally divide one input signal into multiple paths of output signals, the analog beam forming circuit is used for selecting a plurality of selection switches for connecting the radio frequency circuit with one of the combiner, the distributor and the analog beam forming circuit to form a detection loop. Therefore, the analog-to-digital hybrid beam forming large-scale array antenna can be calibrated based on hardware.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a calibration circuit and a calibration method. Background Art

[0002] Mobile base station calibration is a key process to ensure the normal operation of the base station and optimize the communication quality. The main purpose of base station calibration is to ensure that the RF channel of the base station antenna system remains consistent in amplitude and phase, so as to achieve accurate transmission and reception of signals, thereby improving communication quality, reducing signal interference and distortion, and optimizing the coverage of the base station.

[0003] There are two types of mobile base station calibration methods: hardware-based calibration methods and air interface calibration methods. Compared with air interface calibration methods, hardware-based calibration methods have the advantages of saving air interface overhead, fast calibration speed, and no influence from spatial channel quality. However, the hardware-based calibration methods in the prior art are only applicable to all-digital beamforming structures and do not support analog-digital hybrid beamforming large-scale array antennas. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a calibration circuit and a calibration method, thereby enabling the analog-to-digital hybrid beamforming large-scale array antenna to be calibrated based on hardware.

[0005] In a first aspect, an embodiment of the present invention provides a calibration circuit, the circuit comprising:

[0006] Baseband unit;

[0007] M groups of radio frequency circuits, connected to the baseband unit;

[0008] a combiner configured to synthesize an output signal based on multiple input signals;

[0009] A distributor configured to equally divide an input signal into a plurality of output signals;

[0010] Analog beamforming circuits;

[0011] A plurality of selection switches are configured to selectively connect the radio frequency circuit to one of the combiner, the divider and the analog beamforming circuit to form a detection loop.

[0012] In a second aspect, an embodiment of the present invention provides a radio frequency system calibration method, the method specifically comprising:

[0013] Calibrate the radio frequency system according to the calibration circuit;

[0014] Wherein, the calibration circuit comprises:

[0015] Baseband unit;

[0016] M groups of radio frequency circuits, connected to the baseband unit;

[0017] a combiner configured to synthesize an output signal based on multiple input signals;

[0018] A distributor configured to equally divide an input signal into a plurality of output signals;

[0019] Analog beamforming circuits;

[0020] A plurality of selection switches are configured to selectively connect the radio frequency circuit to one of the combiner, the divider and the analog beamforming circuit to form a detection loop.

[0021] The technical solution of the embodiment of the present invention is to set a baseband unit in the calibration circuit, M groups of radio frequency circuits connected to the baseband unit, a combiner configured to synthesize output signals according to multiple input signals, a distributor configured to equally divide an input signal into multiple output signals, an analog beamforming circuit, and multiple selection switches for selecting to connect the radio frequency circuit to one of the combiner, distributor and analog beamforming circuit to form a detection loop. Thus, the analog-to-digital hybrid beamforming large-scale array antenna can be calibrated based on hardware. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0023] Figure 1 is a circuit diagram of a calibration circuit according to an embodiment of the present invention;

[0024] Figure 2 is a flow chart of a first calibration method according to an embodiment of the present invention;

[0025] Figure 3 is a circuit diagram of an embodiment of the present invention when calibrated using the first calibration method;

[0026] Figure 4 is a flow chart of a second calibration method according to an embodiment of the present invention;

[0027] Figure 5 is a circuit diagram of an embodiment of the present invention when calibrated using the second calibration method;

[0028] Figure 6 is a flow chart of a third calibration method according to an embodiment of the present invention;

[0029] Figure 7 is a circuit diagram of an embodiment of the present invention when calibrated using the third calibration method;

[0030] Figure 8 is a flow chart of adjusting each power amplifier according to the first complex signal and the second complex signal according to an embodiment of the present invention;

[0031] Fig. 9 is a flow chart of a fourth calibration method according to an embodiment of the present invention;

[0032] Fig.10 is a circuit diagram of an embodiment of the present invention when calibrating using the fourth calibration method;

[0033] Fig.11 is another circuit diagram of an embodiment of the present invention when calibrated using the fourth calibration method;

[0034] Fig.12 It is a flow chart of adjusting each low noise amplifier according to the third complex signal and the fourth complex signal according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The present application is described below based on embodiments, but the present application is not limited to these embodiments. In the detailed description of the present application below, some specific details are described in detail. It is possible for those skilled in the art to fully understand the present application without the description of these details. In order to avoid confusing the essence of the present application, known methods, processes, flows, components and circuits are not described in detail.

[0036] In addition, persons of ordinary skill in the art will appreciate that the drawings provided herein are for illustration purposes and are not necessarily drawn to scale.

[0037] At the same time, it should be understood that in the following description, "circuit" refers to a conductive loop composed of at least one element or subcircuit through electrical connection or electromagnetic connection. When an element or circuit is said to be "connected to" another element or an element / circuit is said to be "connected between" two nodes, it can be directly coupled or connected to another element or there can be an intermediate element, and the connection between the elements can be physical, logical, or a combination thereof. On the contrary, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there is no intermediate element between the two.

[0038] Unless the context clearly requires otherwise, the words "include", "including" and similar words throughout the application should be interpreted as including rather than exclusive or exhaustive; that is, the meaning is "including but not limited to".

[0039] In the description of this application, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" is two or more.

[0040] Figure 1 is a circuit diagram of a calibration circuit according to an embodiment of the present invention, such as Figure 1 As shown, the calibration circuit includes a baseband unit 1, a radio frequency circuit, a combiner 3, a distributor 4, an analog beamforming circuit 5 and a plurality of selection switches, wherein the radio frequency circuit is a digital beamforming circuit.

[0041] The baseband unit (BBU, Building Baseband Unit) 1 is a unit for processing baseband signals in a telecommunication system. The baseband unit works together with the radio frequency circuit to realize the transmission and processing of wireless signals. In the embodiment of the present invention, the baseband unit 1 controls the radio frequency circuit, the analog beamforming circuit 5 and a plurality of selection switches to form a detection loop, sends signals, receives signals from the radio frequency circuit, analyzes and processes the signals of the radio frequency circuit, and adjusts the complex gain of the radio frequency circuit or the analog beamforming circuit according to the processing results.

[0042] The radio frequency circuit includes a total of M radio frequency circuits, each of which includes a radio frequency transmitting circuit (TX, Transmitter) and a radio frequency receiving circuit (RX, Receiver). As shown in the figure, the i-th radio frequency circuit includes a radio frequency transmitting circuit TXi and a radio frequency receiving circuit RXi, i=1, 2, ..., M. The function of the radio frequency transmitting circuit is to process the signal from the baseband unit in medium and high frequencies, including digital-to-analog conversion / mixing / filtering, and then send it. The function of the radio frequency receiving circuit is to receive the radio frequency signal and perform high and medium frequency processing, including filtering / mixing / analog-to-digital conversion, and send it to the baseband unit. The radio frequency circuit 2 is connected to the baseband unit 1, and the combiner 3 and the distributor 4 are connected to the radio frequency circuit 2 through multiple selection switches. Specifically, the connection relationship between the combiner 3 or the distributor 4 and the radio frequency circuit is changed by adjusting the working state of multiple selection switches, thereby forming a corresponding detection loop to perform corresponding correction steps. The radio frequency circuit includes a coupler 21, which is used to transmit a signal from one circuit to another circuit, or to distribute a signal to multiple circuits to ensure effective transmission and distribution of the signal.

[0043] The function of the combiner 3 is to combine the multiple input signals connected to it into one output signal. In the embodiment of the present invention, the input end of the combiner 3 is connected to M RF transmitting circuits, and the output end is connected to the first RF receiving circuit, that is, the outputs of the M RF transmitting circuits are combined into one output signal, which is sent to the RF receiving circuit and finally sent to the baseband unit 1 for processing.

[0044] The function of the distributor 4 is to divide the power of one input signal into multiple output signals. In the embodiment of the present invention, the input end of the distributor 4 is connected to the coupler output end of the first RF transmitting circuit, and the output end is connected to M RF receiving circuits, that is, one input signal is divided into multiple output signals, which are sent to each RF receiving circuit and finally sent to the baseband unit 1 for processing.

[0045] The analog beamforming circuit 5 includes N phase shift groups, N power synthesis distributors 52, N parallel components, N circulators 54 and antenna arrays. Each phase shift group includes M phase shifters 51, which are respectively connected to M groups of radio frequency circuits 2 to receive signals sent by the radio frequency circuits and send antenna array signals amplified by low noise amplifiers. Each power synthesis distributor 52 is connected to a phase shifter 51 in the N phase shift groups. Each parallel component in the N parallel components is specifically a power amplifier (PA, Power Amplifier) ​​and a low noise amplifier (LNA, Low Noise Amplifier). The function of the power amplifier is to receive a weak signal from a signal source and amplify it to a sufficiently strong level through an amplification circuit to ensure that the signal will not lose information or cannot be normally recognized by the receiving device during transmission due to attenuation, and to reduce the noise and distortion of the signal during transmission by amplifying the signal, thereby improving the signal transmission quality of the entire system. The function of the low noise amplifier is to enhance weak signals, specifically, to amplify these weak signals to a level that can be processed by subsequent circuits or devices, thereby ensuring effective transmission and processing of signals. The circulator 54 is used to isolate the transmit and receive signals to ensure unidirectional transmission of the signals. The antenna array is composed of N antenna elements 55. By precisely controlling the excitation amplitude and phase of each element to form a directional beam, the directionality and gain of the signal transmission are enhanced to achieve efficient and reliable signal transmission and reception. The embedded transmission line 56 next to the antenna element is used to couple the signal of each antenna element for calibration.

[0046] That is to say, the analog beamforming circuit 5 of the embodiment of the present invention includes N links, each link includes a phase shift group, a power synthesis distributor 52, a parallel component, a circulator 54 and an antenna array element 55. Among them, a phase shift group, a power synthesis distributor 52, a parallel component, a circulator 54 and an antenna array element 55 are connected in series in sequence. Take the first link as an example for explanation, wherein the first phase shift group includes M phase shifters 51, each phase shifter 51 is connected to a radio frequency circuit, the first parallel component is connected to the first phase shift group through a single-pole double-throw switch, the first circulator 54 is connected to the first parallel component, and the first antenna array element 55 is connected to the first circulator 54.

[0047] It should be specially noted that the figure only shows the phase shifter 51 connected to the first RF circuit and the second RF circuit. In fact, each of the M RF circuits needs to be connected to N phase shifters. For example, the ellipsis connected to the right side of the Mth RF circuit is actually its corresponding N phase shifters, which are indicated by ellipsis in the figure. Each phase shift group in the figure only shows that it is connected to two phase shifters 51, but in fact, M phase shifters should be connected, which are indicated by ellipsis in the figure. Similarly, the remaining ellipsis respectively represent the antenna array and parallel components not shown in the figure, which will not be described in detail here.

[0048] The plurality of selection switches include a first selection switch K1, a second selection switch K2, M-3 third selection switches K3, a fourth selection switch K4, a fifth selection switch K5, a sixth selection switch K6, a seventh selection switch K7, an eighth selection switch K8, and a ninth selection switch K9.

[0049] The first selection switch K1 is configured to selectively connect the output terminal of the first RF transmission circuit coupler to one of the input terminal of the combiner and the input terminal of the divider.

[0050] The second selection switch K2 includes two switches K2a and K2b, wherein K2a is configured to select to connect the first RF receiving circuit to the output end of the combiner, the output end of the distributor, and one of K2b, and K2b is configured to select to connect the analog beamforming circuit to one of K2a and the first RF transmitting circuit. Therefore, the second selection switch K2 is configured to select to connect the first group of RF circuits to the first phase shifter in the N phase shift groups, the output end of the combiner, and the output end of the distributor.

[0051] M-3 third selection switches K3 respectively select to connect the second group of RF circuits and the fifth to Mth groups of RF circuits, wherein the i-th third selection switch is configured to select to connect the i-th group of RF circuits with one of the output ends of the i-th phase shifter and the distributor in the N phase shift groups, i=2, 5, 6, ..., M, wherein each third selection switch includes two switches K3a and K3b, taking the second group of RF circuits as an example, K3a is configured to select to connect the second RF receiving circuit with one of the output ends of K3b and the distributor, and K3b is configured to select to connect the analog beamforming circuit with one of K3a and the second RF transmitting circuit.

[0052] The fourth selection switch K4 is configured to select to connect one end of the antenna array embedded transmission line to one of the third RF receiving circuit and the third RF transmitting circuit.

[0053] The fifth selection switch K5 is configured to select to connect one end of the antenna array embedded transmission line to one of the fourth RF receiving circuit and the fourth RF transmitting circuit.

[0054] The sixth selection switch K6 includes two switches K6a and K6b, wherein K6a is configured to select to connect the third RF receiving circuit to the output end of the distributor, K6b and one of K4, and K6b is configured to select to connect the analog beamforming circuit and the third RF transmitting circuit to one of K6a. Therefore, the sixth selection switch K6 is configured to select to connect the third group of RF circuits to the distributor, the fourth selection switch and one of the third phase shifter among the M phase shifters in the N phase shift groups.

[0055] The seventh selection switch K7 includes two switches K7a and K7b, wherein K7a is configured to select to connect the fourth RF receiving circuit to the output end of the distributor, K7b and one of K5, and K7b is configured to select to connect the analog beamforming circuit and the fourth RF transmitting circuit to one of K7a. Therefore, the seventh selection switch K7 is configured to select to connect the fourth group of RF circuits to the distributor, the fifth selection switch and one of the fourth phase shifters among the M phase shifters in the N phase shift groups.

[0056] The eighth selection switch K8 is configured to selectively connect the third group of RF circuit coupler output terminals to one of the combiner and the fourth selection switch.

[0057] The ninth selection switch K9 is configured to selectively connect the fourth group of RF circuit coupler output terminals to one of the combiner and the fifth selection switch.

[0058] By setting a plurality of selection switches K1-K9 and selectively connecting the RF circuit 2 with one of the combiner 3, the distributor 4 and the analog beamforming circuit 5 when calibrating different hardware units, a corresponding detection loop is formed to detect the corresponding hardware unit, thereby realizing hardware-based self-calibration based on adding low-cost components to the circuit.

[0059] In the embodiment of the present invention, the baseband unit 1 controls the radio frequency circuit, the analog beamforming circuit 5 and a plurality of selection switches to form different detection loops, so as to achieve calibration of the analog beamforming circuit and the digital beamforming circuit.

[0060] Figure 21 is a flow chart of the first calibration method of an embodiment of the present invention, which is executed by a baseband unit in a downlink time slot. The method is used to calibrate M radio frequency transmission circuits. Specifically, the complex gains of all radio frequency transmission circuits are aligned according to the complex gain of the first radio frequency transmission circuit. Figure 2 As shown, the calibration method comprises the following steps:

[0061] Step S110: Control multiple selection switches to switch so that each radio frequency transmitting circuit and the first radio frequency receiving circuit are connected to the combiner.

[0062] Specifically, the first selection switch is controlled to switch so that the output end of the first RF transmission circuit coupler is connected to the input end of the combiner, the eighth selection switch is controlled to switch so that the output end of the third RF transmission circuit coupler is connected to the input end of the combiner, the ninth selection switch is controlled to switch so that the output end of the fourth RF transmission circuit coupler is connected to the input end of the combiner, and the second selection switch is controlled to switch so that the first RF receiving circuit is connected to the output end of the combiner. The equivalent circuit diagram after switching the switches is as shown in FIG. Figure 3 By adjusting a plurality of selection switches, the input end of the combiner is connected to the output end of each RF transmission circuit coupler, and the output end is connected to the first RF receiving circuit, thereby transmitting the signals sent by each RF transmission circuit to the combiner.

[0063] Step S120: activating the first radio frequency receiving circuit.

[0064] Specifically, by activating the first RF receiving circuit, the baseband unit can receive the signals sent by the various RF transmitting circuits output by the combiner and received by the first RF receiving circuit.

[0065] Step S130: Control each RF transmitting circuit to send a first initial signal to a combiner to output a first signal.

[0066] Specifically, each RF transmission circuit and each power amplifier are powered on, wherein the purpose of powering on each power amplifier is not to affect the operation of other time-frequency resources in the same frame. For M RF circuits, 2M OFDM (Orthogonal Frequency Division Multiplexing) symbols and the time-frequency resources of the center frequency are occupied, all RF transmission circuits send pilot sequences, and the combiner synthesizes the first signal according to the input signals of each RF transmission circuit, and sends it to the baseband unit through the first RF receiving circuit.

[0067] Step S140: Determine a first complex gain of each RF transmitting circuit according to the first signal using a channel estimation algorithm.

[0068] The channel estimation algorithm is a process of estimating the model parameters of a hypothetical channel model from the received data. Specifically, through the channel estimation algorithm, it is determined which part of the first signal is sent by which RF transmitting circuit, that is, the signals sent by each RF transmitting circuit are determined.

[0069] Specifically, the complex gain of each RF transmitting circuit is equivalent to a channel response parameter with a sequence length of 1. The system automatically satisfies the condition of converting linear convolution into circular convolution with a fast algorithm to obtain the channel response, and the complex gain of each RF transmitting circuit can be obtained.

[0070] Step S150: adjust the radio frequency transmitting circuit according to the first complex gain.

[0071] The complex gains of other RF transmission circuits are aligned according to the complex gain of the first RF transmission circuit. It should be noted that the alignment of complex gains is not necessarily based on the first RF transmission circuit, but can also be based on any RF transmission circuit, and the embodiment of the present invention does not limit this.

[0072] Specifically, a first calibration coefficient is calculated according to the first complex gain, and then the baseband unit adjusts the RF transmission circuit according to the first calibration coefficient to achieve alignment. For example, the complex gain of the first RF transmission circuit is G T1 , the complex gain of the second RF transmitting circuit is G T2 ...The complex gain of the Mth RF transmission circuit is G TM , then for the i-th RF transmission circuit, since its complex gain is G Ti , determine the first calibration coefficient of the i-th RF transmitting circuit as G Ti / G T1 Specifically, the complex gain of the ith RF transmission circuit is divided by its first calibration coefficient, and the adjusted complex gain of the ith RF transmission circuit is G T1 , that is, the complex gain of all RF transmission circuits is adjusted to G T1 , the complex gain of the RF transmitting circuit is aligned, and the calibration of the RF transmitting circuit is completed.

[0073] In general, in the present calibration method, firstly, all the RF transmission circuits and power amplifiers are powered on, and the first selection switch, the eighth selection switch and the ninth selection switch are switched so that the input end of the combiner is connected to each RF transmission circuit, and the output end is connected to the first RF receiving circuit. Then, the pilot sequence is sent through all the RF transmission circuits, and the baseband unit receives the pilot sequence from the first RF receiving circuit, and executes the channel estimation algorithm to obtain the complex gain of each RF transmission circuit, and finally the first RF transmission circuit is used as a reference for alignment.

[0074] The embodiment of the present invention provides a baseband unit in the calibration circuit, M groups of radio frequency circuits connected to the baseband unit, a combiner configured to synthesize output signals according to multiple input signals, a distributor configured to equally divide an input signal into multiple output signals, an analog beamforming circuit, and multiple selection switches for selecting to connect the radio frequency circuit to one of the combiner, distributor, and analog beamforming circuit to form a detection loop. Thus, the analog-to-digital hybrid beamforming large-scale array antenna can be calibrated based on hardware.

[0075] Figure 4 1 is a flow chart of a second calibration method according to an embodiment of the present invention, which is executed by a baseband unit in an uplink time slot. This method is used to calibrate M radio frequency receiving circuits. Specifically, the complex gains of all radio frequency receiving circuits are aligned according to the complex gain of the first radio frequency receiving circuit. Figure 4 As shown, the calibration method comprises the following steps:

[0076] Step S210: Control multiple selection switches to switch so that the first radio frequency transmitting circuit and each radio frequency receiving circuit are connected to the distributor.

[0077] Specifically, the first selection switch is controlled to switch so that the first RF transmitting circuit is connected to the input end of the distributor, the second selection switch is controlled to switch so that the first RF receiving circuit is connected to the output end of the distributor, the third selection switch is controlled to switch so that the second RF receiving circuit, the fifth RF receiving circuit, the sixth RF receiving circuit...the Mth RF receiving circuit are connected to the output end of the combiner, the sixth selection switch is controlled to switch so that the third RF receiving circuit is connected to the output end of the combiner, and the seventh selection switch is controlled to switch so that the fourth RF receiving circuit is connected to the output end of the combiner. The specific circuit diagram after switching the switches is as shown in FIG. Figure 5 By adjusting a plurality of selection switches, the input end of the distributor is connected to the first RF transmitting circuit, and the output end is connected to each RF receiving circuit, thereby distributing the signal sent by the first RF transmitting circuit to each RF receiving circuit.

[0078] Step S220: Activate each radio frequency receiving circuit.

[0079] Specifically, by activating each RF receiving circuit, the baseband unit can receive the signal received by each RF receiving circuit. Meanwhile, each low noise amplifier is powered off to prevent signal interference from the antenna array.

[0080] Step S230: Control the first RF transmitting circuit to transmit the second initial signal to the distributor, and output the second signal through each RF receiving circuit.

[0081] The second initial signal is two bits 1 with a phase of 0. Specifically, the first RF transmission circuit occupies 2 symbols and time-frequency resources of all frequencies, transmits two bits 1 with a phase of 0, and the second signal of the second initial signal after passing through each RF circuit is received by the baseband unit.

[0082] Step S240: Determine a second complex gain of each of the RF receiving circuits according to the second signal.

[0083] After the baseband unit receives the second signal after passing through each radio frequency circuit, the second complex gain of the corresponding radio frequency receiving circuit is determined according to the second signal.

[0084] Step S250: Adjust the RF receiving circuit according to the second complex gain.

[0085] Specifically, after calculating the second complex gain of each RF receiving circuit, specifically, the second calibration coefficient is calculated according to the second complex gain, and then the RF receiving circuit is adjusted by the baseband unit according to the calibration coefficient to achieve alignment. Similar to the adjustment method in the first calibration method, the embodiment of the present invention is not described in detail here.

[0086] In general, in this calibration method, firstly, each RF receiving circuit is activated, and each low noise amplifier is powered off, and the first selection switch, the second selection switch, the third selection switch, the sixth selection switch, and the seventh selection switch are switched so that the input end of the distributor is connected to the first RF transmitting circuit, and the output end is connected to each RF receiving circuit. Then, two bits 1 are sent through the first RF transmitting circuit, and the baseband unit receives signals from each RF receiving circuit and obtains the complex gain of each RF receiving circuit, and finally the first RF receiving circuit is used as a reference for alignment.

[0087] The embodiment of the present invention provides a baseband unit in the calibration circuit, M groups of radio frequency circuits connected to the baseband unit, a combiner configured to synthesize output signals according to multiple input signals, a distributor configured to equally divide an input signal into multiple output signals, an analog beamforming circuit, and multiple selection switches for selecting to connect the radio frequency circuit to one of the combiner, distributor, and analog beamforming circuit to form a detection loop. Thus, the analog-to-digital hybrid beamforming large-scale array antenna can be calibrated based on hardware.

[0088] Figure 6 : is a flow chart of a third calibration method of an embodiment of the present invention, which is executed by a baseband unit in a downlink time slot. This method is used to calibrate the gains of N power amplifiers. Specifically, the complex gains of all power amplifiers are aligned according to the complex gain of the first power amplifier. Figure 6 As shown, the calibration method comprises the following steps:

[0089] Step S310: Control multiple selection switches to switch so that the third RF receiving circuit and the fourth RF receiving circuit are connected to both ends of the antenna array embedded transmission line.

[0090] Specifically, the fourth selection switch and the sixth selection switch are controlled to switch so that the third RF receiving circuit is connected to one end of the antenna array embedded transmission line, and the fifth selection switch and the seventh selection switch are controlled to switch so that the fourth RF receiving circuit is connected to the other end of the antenna array embedded transmission line. The specific circuit diagram after switching is as follows: Figure 7 By adjusting a plurality of selection switches, the output end of the antenna array is connected to each RF receiving circuit.

[0091] Step S320: Activate the third RF receiving circuit and the fourth RF receiving circuit.

[0092] Specifically, the third RF receiving circuit and the fourth RF receiving circuit are activated so that the third RF receiving circuit and the fourth RF receiving circuit receive signals.

[0093] Step S330: Turn on the power amplifiers in sequence by controlling the switches to determine the first complex signal received by the third RF receiving circuit and the second complex signal received by the fourth RF receiving circuit.

[0094] Specifically, this step is to iteratively repeat steps S331-S333 N times, wherein:

[0095] Step S331, turn on the i-th power amplifier.

[0096] Since a total of N cycles are performed, in the first cycle, the first power amplifier is turned on, in the second cycle, the second power amplifier is turned on, and so on, N power amplifiers are turned on in sequence. The power amplifier is turned on by turning the selection switch on the parallel component to the parallel branch where the power amplifier is located, and powering on the power amplifier to turn it on. Figure 7 It is a schematic diagram after the first power amplifier is turned on according to an embodiment of the present invention.

[0097] Step S332: Control the first RF transmitting circuit to transmit a third initial signal to the i-th power amplifier.

[0098] Specifically, the first cycle is used for explanation, that is, the first power amplifier is turned on, and the other power amplifiers are not working. The first RF transmitting circuit occupies 2 symbols and the time-frequency resources of all frequencies to send the third initial signal through the first power amplifier to the first antenna array element. Among them, the third initial signal can be a signal of two bits 1 with phases of 0, or it can be other types of signals, and the embodiment of the present invention does not limit this. The third initial signal is coupled through an embedded transmission line (ETL) and sent to the third RF receiving circuit and the fourth RF receiving circuit. Among them, the embedded transmission line is a special cable or structure used to transmit RF signals. By efficiently transmitting high-frequency signals, it ensures the stable transmission of signals in the RF circuit. In the RF circuit, due to the high frequency of the signal, it is necessary to use a transmission line with specific impedance and transmission characteristics to ensure the integrity of the signal.

[0099] Step S333: determine the first complex signal received by the third RF receiving circuit and the second complex signal received by the fourth RF circuit.

[0100] Specifically, still using the first cycle as an example, after the third initial signal is coupled through the embedded transmission line and sent to the third RF circuit and the fourth RF circuit, since the third initial signal is a signal of two bits 1 with phases of 0, the baseband unit determines the first complex signal of two bits received from the third RF receiving circuit, and averages the two-bit signal to obtain V1. Accordingly, the baseband unit determines the second complex signal of two bits received from the fourth RF receiving circuit, and averages the two-bit signal to obtain W1.

[0101] The first complex signal and the second complex signal are used to represent amplitude information and phase information. When aligning the PA, both the amplitude information and the phase information need to be aligned.

[0102] Through N cycles of step S331 to step S333, Vi and Wi (i=1, 2, ... N) are obtained.

[0103] Step S340: adjust each of the power amplifiers according to the first complex signal and the second complex signal.

[0104] Specifically, according to the N groups of first complex signals V obtained in the N cycles in step S330 i and the second complex signal W i Determine the power amplifiers PA1, PA2, ... N The gain difference of each power amplifier is adjusted through the baseband unit.

[0105] Specifically, the adjustment parameter is obtained by calculating each first complex signal and each second complex signal according to the following formula:

[0106]

[0107] mag_db(β t i,i+1 )≈mag_db(κ i,i+1 )(2)

[0108] β t i,i+1 =a t,1(i+1) / a t,1i (3)

[0109]

[0110] Among them, κ i,i+1 is the first correlation parameter between the ith power amplifier and the (i+1)th power amplifier, a t,1i is the gain of the ith power amplifier, the 1 in the subscript 1i indicates that the calibration signal comes from the first RF transmitting circuit, β t i,i+1 is the gain ratio of the i+1th power amplifier to the ith power amplifier, arg(β t i,i+1 ) is the complex number β t i,i+1 The principal value of the argument, mag_db(β t i,i+1 ) is β t i,i+1 decibel value.

[0111] Figure 8 is a flow chart of a method for adjusting each power amplifier according to a first complex signal and a second complex signal according to an embodiment of the present invention. Figure 8 As shown, the method for adjusting each power amplifier specifically includes:

[0112] Step S341: Calculate N-1 groups of first correlation parameters according to the first complex signal and the second complex signal.

[0113] Specifically, through formula (1), the first related parameters of the first power amplifier and the second power amplifier, the first related parameters of the second power amplifier and the third power amplifier, and so on, the first related parameters of the N-1th power amplifier and the Nth power amplifier are calculated respectively according to the first complex signal and the second complex signal.

[0114] Step S342: Determine the adjacent gain ratios of N-1 power amplifiers.

[0115] Specifically, the adjacent gain ratio of the ith power amplifier is the ratio of the gain of the ith power amplifier to the gain of the i-1th power amplifier. It can be concluded that determining the adjacent gain ratio of the N-1th power amplifier is actually to calculate the gain ratio of the second power amplifier to the first power amplifier, the gain ratio of the third power amplifier to the second power amplifier, and the gain ratio of the Nth power amplifier to the N-1th power amplifier as the adjacent gain ratio of the second power amplifier, the third power amplifier, and the Nth power amplifier.

[0116] Since formula (2) is an empirical formula in the prior art, the gain ratio of a power amplifier to the previous power amplifier actually corresponds to N-1 first related parameters. Specifically, taking the second power amplifier as an example, it can be seen from formula (2) and formula (3) that the gain ratio of the second power amplifier to the first power amplifier is approximately equal to the first related parameter of the first power amplifier to the second power amplifier, that is, the gain ratio can be replaced by the first related parameter to perform the subsequent calculation.

[0117] Step S343: Calculate the gain ratios of each power amplifier to the first power amplifier according to the N-1 adjacent gain ratios.

[0118] Specifically, the gain ratios of the second power amplifier, the third power amplifier, ... and the Nth power amplifier to the first power amplifier are calculated respectively according to formula (5). For general consideration, the i-th (i>1)th power amplifier is taken as an example for explanation. It can be seen from formula (5) that the gain ratio of the i-th power amplifier to the first power amplifier is actually equal to the product of the adjacent gain ratios of the second power amplifier, the third power amplifier ... the i-th power amplifier, and the adjacent gain ratio of the j-th power amplifier is approximately equal to the first related parameter of the j-th power amplifier and the j-1-th power amplifier. Therefore, the gain ratio of the i-th power amplifier to the first power amplifier can actually be approximated by the cumulative multiplication of the first related parameters of the first power amplifier and the second power amplifier, the second power amplifier and the third power amplifier ... the i-1-th power amplifier and the i-th power amplifier.

[0119] Step S344: adjust each power amplifier according to the gain ratio of each power amplifier to the first power amplifier.

[0120] Specifically, after the gain ratios of the power amplifiers to the first power amplifier are calculated, the complex gains of the other power amplifiers are aligned according to the complex gain of the first power amplifier. Specifically, this is similar to the alignment method in the first calibration method, and will not be described in detail in the embodiment of the present invention.

[0121] The embodiment of the present invention provides a baseband unit in the calibration circuit, M groups of radio frequency circuits connected to the baseband unit, a combiner configured to synthesize output signals according to multiple input signals, a distributor configured to equally divide an input signal into multiple output signals, an analog beamforming circuit, and multiple selection switches for selecting to connect the radio frequency circuit to one of the combiner, distributor, and analog beamforming circuit to form a detection loop. Thus, the analog-to-digital hybrid beamforming large-scale array antenna can be calibrated based on hardware.

[0122] In general, in this calibration method, the first RF transmitting circuit and the first power amplifier are powered on, and the third RF receiving circuit and the fourth RF receiving circuit are connected to both sides of the embedded transmission line by switching the fourth selection switch, the fifth selection switch, the sixth selection switch and the seventh selection switch, and the third RF receiving circuit and the fourth RF receiving circuit are activated. Then the first RF transmitting circuit sends two bits 1, which reach the first antenna array element through the first power amplifier, are coupled through the embedded transmission line, and are received by the third RF receiving circuit and sent to the baseband unit to obtain V1 and the fourth RF receiving circuit and sent to the baseband unit to obtain W1. By repeating the above steps, V i and W i (i=2,3,…,N). Finally, according to V i and W i The gain ratios of the power amplifiers to the first power amplifier are obtained, and the gains of the power amplifiers are aligned according to the gain ratios.

[0123] Fig. 9 1 is a flow chart of a fourth calibration method according to an embodiment of the present invention, which is executed by a baseband unit in an uplink time slot. The method is used to calibrate the gains of N low noise amplifiers. Specifically, the complex gains of all low noise amplifiers are aligned according to the complex gain of the first low noise amplifier, such as Fig. 9 As shown, the calibration method comprises the following steps:

[0124] Step S410: Activate the first radio frequency receiving circuit.

[0125] Specifically, by activating the first RF receiving circuit, the baseband unit can receive the signals sent by the third RF circuit and the fourth RF circuit that are received by the first RF receiving circuit.

[0126] Step S420: determining a third complex signal sent by a third RF transmitting circuit and a fourth complex signal sent by a fourth RF transmitting circuit according to the received data of the first RF receiving circuit by sequentially turning on low noise amplifiers.

[0127] Specifically, this step is to iteratively repeat steps S421-S427 N times, wherein:

[0128] Step S421, turning on the i-th low noise amplifier.

[0129] Specifically, in the first cycle, the first low noise amplifier is turned on, in the second cycle, the second low noise amplifier is turned on, and so on, N low noise amplifiers are turned on in sequence.

[0130] Step S422: Control multiple selection switches to switch so that the third RF transmitting circuit and the fourth RF receiving circuit are connected to two ends of the antenna array embedded transmission line, and the fourth RF receiving circuit is activated.

[0131] Taking the first low noise amplifier as an example, specifically, the fourth selection switch and the eighth selection switch are controlled to switch so that the output end of the third RF transmission circuit coupler is connected to one end of the antenna array embedded transmission line, and the fifth selection switch and the seventh selection switch are controlled to switch so that the fourth RF receiving circuit is connected to the other end of the antenna array embedded transmission line, forming a loop passing through the antenna array embedded transmission line. The specific circuit is as follows Fig.10 By activating the third RF transmitting circuit and the fourth RF receiving circuit, a signal transmission loop is formed.

[0132] Step S423: Control the third RF transmitting circuit to send a fourth initial signal to the antenna array embedded transmission line, and the other end is received by the fourth RF receiving circuit.

[0133] Specifically, after the third RF transmitting circuit is connected to one end of the antenna array embedded transmission line, the third RF transmitting circuit is controlled to send a fourth initial signal. In an optional implementation, the fourth initial signal has two phases of 0 bit 1.

[0134] Step S424, receiving, through the first RF receiving circuit, a third complex signal that is coupled to the first antenna array element from the embedded transmission line and is amplified by the first low noise amplifier;

[0135] The fourth initial signal sent by the third RF transmitting circuit is received by the first RF receiving circuit and coupled from the embedded transmission line to the third complex signal P after the i-th low noise amplifier through the i-th antenna array element. i Thus, through N cycles, the third complex signals P1, P2, ..., P passing through N antenna array elements and N low noise amplifiers are obtained in sequence. N .

[0136] Step S425: Control the switching of the multiple selection switches so that the fourth RF transmitting circuit and the third RF receiving circuit are connected to two ends of the antenna array embedded transmission line, and activate the third RF receiving circuit.

[0137] Specifically, the fifth selection switch and the ninth selection switch are controlled to switch so that the output end of the fourth RF transmission circuit coupler is connected to one end of the antenna array embedded transmission line, and the fourth selection switch and the sixth selection switch are controlled to switch so that the third RF receiving circuit is connected to the other end of the antenna array embedded transmission line, forming a loop passing through the antenna array embedded transmission line. The specific circuit is as follows Fig.11 By activating the fourth RF transmitting circuit and the third RF receiving circuit, a signal transmission loop is formed.

[0138] Step S426: Control the fourth radio frequency transmitting circuit to transmit a fourth initial signal to one end of the antenna array embedded transmission line.

[0139] Similar to step S423, details are not given here.

[0140] Step S427: Receive, through the first RF receiving circuit, a fourth complex signal that is coupled to the first antenna array element from the embedded transmission line and amplified by the first low noise amplifier.

[0141] Similar to step S424, the fourth initial signal sent by the fourth RF transmitting circuit is received by the first RF receiving circuit, and is coupled from the embedded transmission line to the fourth complex signal Q after the i-th low noise amplifier through the i-th antenna array element. i After N cycles, the fourth initial signal sent by the fourth RF transmitting circuit is sequentially obtained, and the fourth complex signals Q1, Q2, ..., Q1 of the fourth initial signal passed through the N antenna array elements and the N low noise amplifiers are obtained. N .

[0142] In summary, the third complex signals P1, P2, ..., P are obtained through N cycles of step S421 to step S427. N and the fourth complex signal Q1, Q2...Q N .

[0143] Step S430: adjust each of the low noise amplifiers according to the third complex signal and the fourth complex signal.

[0144] Specifically, according to the N groups of third complex signals P obtained in the N cycles in step S421-step S427 i and the fourth complex signal Q i Determine the individual low noise amplifiers LNA1, LNA2, ... LNA N The adjustment method is used to adjust each low noise amplifier through the baseband unit.

[0145] Specifically, the adjustment parameter is obtained by calculating each third complex signal and each fourth complex signal according to the following formula:

[0146]

[0147] mag_db(β r i,i+1 )≈mag_db(λ i,i+1 )(8)

[0148]

[0149] Among them, λ i,i+1 is the second correlation parameter between the i-th low noise amplifier and the i+1-th low noise amplifier, a r,1i is the gain of the i-th low noise amplifier. The 1 in the subscript 1i indicates that the calibration signal is received by the first RF receiving circuit. r i,i+1 is the gain ratio of the i+1th low noise amplifier to the ith low noise amplifier, arg(β r i,i+1 ) is β r i,i+1 The principal value of the argument, mag_db(β r i,i+1 ) is β r i,i+1 decibel value.

[0150] Fig.12 is a flow chart of a method for adjusting each low noise amplifier according to the third complex signal and the fourth complex signal according to an embodiment of the present invention. Fig.12 As shown, the method for adjusting each low noise amplifier specifically includes:

[0151] Step S431: Calculate N-1 groups of second related parameters according to the third complex signal and the fourth complex signal.

[0152] Specifically, formula (6) is used to calculate the second correlation parameters between the first low noise amplifier and the second low noise amplifier, the second correlation parameters between the second low noise amplifier and the third low noise amplifier, and so on, the second correlation parameters between the N-1th low noise amplifier and the Nth low noise amplifier according to the third complex signal and the fourth complex signal.

[0153] Step S432: Determine the adjacent gain ratios of N-1 low noise amplifiers.

[0154] Specifically, the adjacent gain ratio of the ith low noise amplifier is the ratio of the gain of the ith low noise amplifier to the gain of the i-1th low noise amplifier. It can be concluded that determining the adjacent gain ratio of the N-1 low noise amplifiers is actually to calculate the gain ratio of the second low noise amplifier to the first low noise amplifier, the gain ratio of the third low noise amplifier to the second low noise amplifier...the gain ratio of the Nth low noise amplifier to the N-1th low noise amplifier as the adjacent gain ratio of the second low noise amplifier, the third low noise amplifier...the Nth low noise amplifier.

[0155] Among them, since formula (8) is an empirical formula in the prior art, the gain ratio of the low noise amplifier to the previous low noise amplifier actually corresponds to N-1 second related parameters. Specifically, taking the second low noise amplifier as an example, it can be seen from formula (7) and formula (8) that the gain ratio of the second low noise amplifier to the first low noise amplifier is approximately equal to the second related parameter of the first low noise amplifier to the second low noise amplifier, that is, the gain ratio can be replaced by the second related parameter to perform the subsequent calculation.

[0156] Step S433: Calculate the gain ratios of each power amplifier to the first power amplifier according to the N-1 adjacent gain ratios.

[0157] Specifically, the gain ratios of the second low noise amplifier, the third low noise amplifier, ... and the Nth low noise amplifier to the first low noise amplifier are calculated respectively according to formula (10). For general consideration, the i-th (i>1) low noise amplifier is taken as an example for explanation. It can be seen from formula (10) that the gain ratio of the i-th low noise amplifier to the first low noise amplifier is actually equal to the product of the adjacent gain ratios of the second low noise amplifier, the third low noise amplifier ... the i-th low noise amplifier, and the adjacent gain ratio of the j-th low noise amplifier is approximately equal to the second related parameter of the j-th low noise amplifier and the j-1-th low noise amplifier. Therefore, the gain ratio of the i-th low noise amplifier to the first low noise amplifier can actually be approximated by the cumulative multiplication of the second related parameters of the first low noise amplifier and the second low noise amplifier, the second low noise amplifier and the third low noise amplifier ... the i-1-th low noise amplifier and the i-th low noise amplifier.

[0158] Step S434: adjusting each low noise amplifier according to a gain ratio between each low noise amplifier and the first low noise amplifier.

[0159] Specifically, after calculating the gain ratios of each low noise amplifier to the first low noise amplifier, the complex gains of the other low noise amplifiers are aligned according to the complex gain of the first low noise amplifier. Similar to the alignment method in the first calibration method, this embodiment of the present invention will not be described in detail.

[0160] In general, in this calibration method, firstly, the first RF receiving circuit is activated, and the first low noise amplifier is powered on. The third RF transmitting circuit and the fourth RF receiving circuit are connected to the two ends of the embedded transmission line to form a loop by controlling the fourth selection switch, the fifth selection switch, the seventh selection switch and the eighth selection switch, and the third RF transmitting circuit and the fourth RF receiving circuit are activated. Two bits 1 are sent to one end of the embedded transmission line of the antenna array through the third RF transmitting circuit, and the other end is received by the fourth RF receiving circuit. And the P1 signal that is coupled to the first antenna array element from the embedded transmission line and amplified by the first low noise amplifier is obtained in the first RF receiving circuit. In the same way, the fourth RF transmitting circuit and the third RF transmitting circuit are controlled to be connected to the two ends of the embedded transmission line to form a loop, and two bits 1 are sent through the fourth RF transmitting circuit, and the Q1 signal is obtained in the first RF receiving circuit. By repeating the above steps and powering on the i-th low noise amplifier in turn, P is obtained. i and Q i (i=2, 3, ..., N). Finally, according to P i and Q i The gain ratios of the low noise amplifiers to the first low noise amplifier are obtained, and the low noise amplifiers are aligned according to the gain ratios.

[0161] The embodiment of the present invention provides a baseband unit in the calibration circuit, M groups of radio frequency circuits connected to the baseband unit, a combiner configured to synthesize output signals according to multiple input signals, a distributor configured to equally divide an input signal into multiple output signals, an analog beamforming circuit, and multiple selection switches for selecting to connect the radio frequency circuit to one of the combiner, distributor, and analog beamforming circuit to form a detection loop. Thus, the analog-to-digital hybrid beamforming large-scale array antenna can be calibrated based on hardware.

[0162] It should be noted that the above four calibration methods all belong to main process calibration and are all performed at the center frequency. In some embodiments, the method also includes a sub-process calibration, which is specifically used to calibrate the RF transmitting circuit, RF receiving circuit, power amplifier and low noise amplifier at all frequencies.

[0163] The following is an example of calibrating the RF transmission at all frequencies. The calibration of the RF receiving circuit, power amplifier and low noise amplifier at all frequencies is similar. First, power on the first RF transmitting circuit, control the first selection switch to switch so that the first RF transmitting circuit is connected to the input end of the combiner, and control the second selection switch to switch so that the first RF receiving circuit is connected to the output end of the combiner. Then occupy 2 symbols and all frequencies within the system frequency band time-frequency resources, and the first RF transmitting circuit sends two bits 1 with a phase of 0 at L frequency points. The baseband unit receives each carrier pilot signal from the first RF receiving circuit, and two data are received for each frequency point. The two data of each frequency point are averaged to obtain the gain G T1,l (l=1, 2……L). Power on the other M-1 RF transmission circuits and the corresponding power amplifiers in turn, and connect the RF transmission circuit to the input of the combiner and the first RF receiving circuit to the output of the combiner to obtain G in the same way. Tj，l (l=1, 2...L, j=2, 3...M). Tj,l Represents the gain of the jth RF transmitting circuit at frequency point l.

[0164] Specifically, calculating the calibration coefficient is to calculate the ratio of the gain of the jth RF transmission circuit at the frequency point l to the gain of the first RF transmission circuit at the center frequency point (L / 2), which is calculated by the following formula:

[0165]

[0166] The numerator on the right side of the multiplication sign in the above formula is the ratio of the gain of the jth RF transmission circuit to the gain of the first RF transmission circuit calculated in the main process, which has been calculated in the main process. The numerator on the left side of the multiplication sign is the gain of the jth RF transmission circuit at frequency point l, and the denominator is the gain of the jth RF transmission circuit at the center frequency point. These two values ​​can be obtained when the jth RF transmission circuit and the corresponding power amplifier are powered on. After calculating the calibration coefficient, the gain of each RF circuit at each frequency point is calibrated according to the calibration coefficient.

[0167] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, devices (equipment) or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware. Moreover, the present application may adopt a computer program product implemented on one or more computer-readable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0168] The present application is described with reference to flowcharts of methods, apparatuses (devices) and computer program products according to embodiments of the present application. It should be understood that each process in the flowchart can be implemented by computer program instructions.

[0169] These computer program instructions may be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device that implements the process Figure 1 A function specified in a process or multiple processes.

[0170] These computer program instructions may also be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce the instructions for implementing the process Figure 1 A device that specifies functions in a process or multiple processes.

[0171] Another embodiment of the present invention relates to a non-volatile storage medium for storing a computer-readable program, wherein the computer-readable program is used for a computer to execute part or all of the above method embodiments.

[0172] That is, those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by specifying relevant hardware through a program, and the program is stored in a storage medium, including several instructions for a device (which can be a single-chip microcomputer, chip, etc.) or a processor (processor) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0173] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A calibration circuit, characterized in that: The circuit comprises: Baseband unit; M groups of radio frequency circuits, connected to the baseband unit; a combiner configured to synthesize an output signal based on multiple input signals; A distributor configured to equally divide an input signal into a plurality of output signals; Analog beamforming circuits; A plurality of selection switches are configured to selectively connect the radio frequency circuit to one of the combiner, the divider and the analog beamforming circuit to form a detection loop.

2. The calibration circuit according to claim 1, characterized in that: The radio frequency circuit includes a radio frequency transmitting circuit and a radio frequency receiving circuit.

3. The calibration circuit according to claim 2, characterized in that: The analog beamforming circuit comprises: N phase shift groups, each phase shift group includes M phase shifters, and the M phase shifters are respectively connected to M groups of radio frequency circuits; N power synthesis distributors are respectively connected to N phase shift groups; N parallel components are respectively connected to the N power synthesis distributors, and each parallel component includes a parallel power amplifier and a low noise amplifier; N circulators are connected to N parallel components respectively; The antenna array includes N antenna elements, each of which is connected to N circulators; Embedded transmission line.

4. The calibration circuit according to claim 3, characterized in that: The plurality of selection switches include: A first selection switch is configured to selectively connect the output terminal of the first RF transmission circuit coupler to one of the input terminal of the combiner and the input terminal of the distributor; A second selection switch is configured to select and connect the first group of radio frequency circuits to one of the first phase shifter in the N phase shift groups, the output end of the combiner, and the output end of the distributor; M-3 third selection switches, respectively selecting to connect the second group of radio frequency circuits and the fifth to M groups of radio frequency circuits, wherein the i-th third selection switch is configured to select to connect the i-th group of radio frequency circuits to one of the output ends of the i-th phase shifter and the distributor in the N phase shift groups, i=2, 5, 6, ..., M; a fourth selection switch configured to selectively connect one end of the embedded transmission line to one of the output ends of the third RF receiving circuit and the third RF transmitting circuit coupler; a fifth selection switch configured to selectively connect one end of the embedded transmission line to one of the fourth RF receiving circuit and the fourth RF transmitting circuit; a sixth selection switch configured to select and connect the third group of radio frequency circuits to one of the distributor, the fourth selection switch and the third phase shifter in the N phase shift groups; a seventh selection switch configured to select and connect the fourth group of radio frequency circuits to one of the distributor, the fifth selection switch, and the fourth phase shifter in the N phase shift groups; an eighth selection switch configured to selectively connect the third group of radio frequency circuits to one of the combiner and the fourth selection switch; A ninth selection switch is configured to selectively connect the fourth group of radio frequency circuits to one of the combiner and the fifth selection switch.

5. The calibration circuit according to claim 4, characterized in that: The baseband unit is configured to control the switching of the first selection switch, the eighth selection switch and the ninth selection switch so that each of the RF transmitting circuits and the first RF receiving circuit is connected to the combiner, activate the first RF receiving circuit, control each RF transmitting circuit to send a first initial signal to the combiner through the first RF receiving circuit to output a first signal, determine a first complex gain of each RF transmitting circuit according to the first signal through a channel estimation algorithm, and adjust the RF transmitting circuit according to the first complex gain.

6. The calibration circuit according to claim 4, characterized in that: The baseband unit is configured to control the switching of the first selection switch, the second selection switch, the third selection switch, the sixth selection switch and the seventh selection switch so that the first RF transmitting circuit and each RF receiving circuit are connected to the distributor, activate each RF receiving circuit, control the first RF transmitting circuit to send a second initial signal to the distributor, output a second signal through each RF receiving circuit, determine a second complex gain of each RF receiving circuit according to the second signal, and adjust the RF receiving circuit according to the second complex gain.

7. The calibration circuit according to claim 4, characterized in that: The baseband unit is configured to control the fourth selection switch, the fifth selection switch, the sixth selection switch and the seventh selection switch so that the third RF receiving circuit and the fourth RF receiving circuit are connected to both ends of the embedded transmission line, activate the third RF receiving circuit and the fourth RF receiving circuit, turn on each power amplifier in sequence by controlling the switch to determine the first complex signal received by the third RF receiving circuit and the second complex signal received by the fourth RF receiving circuit, and adjust each power amplifier according to the first complex signal and the second complex signal, wherein the determination of the first complex signal received by the third RF receiving circuit and the second complex signal received by the fourth RF receiving circuit is specifically to iteratively perform the following steps N times: turn on the i-th power amplifier, control the first RF transmitting circuit to send the third initial signal to the i-th power amplifier, and determine the first complex signal received by the third RF receiving circuit and the second complex signal received by the fourth RF circuit.

8. The calibration circuit according to claim 4, characterized in that: The baseband unit is configured to activate the first RF receiving circuit, determine the third complex signal sent by the third RF transmitting circuit and the fourth complex signal sent by the fourth RF transmitting circuit according to the received data of the first RF receiving circuit by sequentially turning on the low noise amplifiers, and adjust each of the low noise amplifiers according to the third complex signal and the fourth complex signal, wherein the method of determining the third complex signal sent by the third RF transmitting circuit and the fourth complex signal sent by the fourth RF transmitting circuit according to the received data of the first RF receiving circuit by sequentially turning on the low noise amplifiers is specifically to iteratively perform the following steps N times: turn on the i-th low noise amplifier, control the eighth selected The first selection switch, the fourth selection switch, the seventh selection switch and the fifth selection switch are switched so that the output end of the third RF transmitting circuit coupler and the fourth RF receiving circuit are connected to both ends of the embedded transmission line, the third RF transmitting circuit is controlled to send a fourth initial signal, and the third complex signal is received through the first RF receiving circuit, the ninth selection switch, the fifth selection switch, the fourth selection switch and the sixth selection switch are controlled to switch so that the output end of the fourth RF transmitting circuit coupler and the third RF receiving circuit are connected to both ends of the embedded transmission line, the fourth RF transmitting circuit is controlled to send a fourth initial signal, and the fourth complex signal is received through the first RF receiving circuit.

9. A calibration method, suitable for calibrating a circuit, characterized in that: The calibration circuit includes a baseband unit, M groups of radio frequency circuits, a combiner, a distributor, an analog beamforming circuit and a plurality of selection switches, the M groups of radio frequency circuits are connected to the baseband unit, the combiner is configured to synthesize an output signal according to multiple input signals, and the distributor is configured to equally divide an input signal into multiple output signals. The method includes: The radio frequency circuit is selectively connected to one of the combiner, the divider and the analog beamforming circuit by controlling the plurality of selection switches to form a detection loop.

10. The method according to claim 9, characterized in that The step of controlling the plurality of selection switches to select and connect the radio frequency circuit to one of the combiner, the distributor, and the analog beamforming circuit to form a detection loop comprises: Control the first selection switch, the eighth selection switch, and the ninth selection switch to switch so that each RF transmission circuit and the first RF receiving circuit are connected to the combiner, activate the first RF receiving circuit, control each RF transmission circuit to send a first initial signal to the combiner through the first RF receiving circuit to output a first signal, determine a first complex gain of each RF transmission circuit according to the first signal through a channel estimation algorithm, and adjust the RF transmission circuit according to the first complex gain; or Control the switching of the first selection switch, the second selection switch, the third selection switch, the sixth selection switch and the seventh selection switch so that the first RF transmitting circuit and each RF receiving circuit are connected to the distributor, activate each RF receiving circuit, control the first RF transmitting circuit to send a second initial signal to the distributor, output a second signal through each RF receiving circuit, determine a second complex gain of each RF receiving circuit according to the second signal, and adjust the RF receiving circuit according to the second complex gain; or Control the fourth selection switch, the fifth selection switch, the sixth selection switch and the seventh selection switch so that the third RF receiving circuit and the fourth RF receiving circuit are connected to both ends of the embedded transmission line, activate the third RF receiving circuit and the fourth RF receiving circuit, turn on each power amplifier in sequence by controlling the switches to determine the first complex signal received by the third RF receiving circuit and the second complex signal received by the fourth RF receiving circuit, and adjust each power amplifier according to the first complex signal and the second complex signal, wherein the determination of the first complex signal received by the third RF receiving circuit and the second complex signal received by the fourth RF receiving circuit is specifically to iteratively perform the following steps N times: turn on the i-th power amplifier, control the first RF transmitting circuit to send the third initial signal to the i-th power amplifier, determine the first complex signal received by the third RF receiving circuit and the second complex signal received by the fourth RF circuit, or Activate the first RF receiving circuit, determine the third complex signal sent by the third RF transmitting circuit and the fourth complex signal sent by the fourth RF transmitting circuit according to the received data of the first RF receiving circuit by sequentially turning on the low noise amplifiers, and adjust each of the low noise amplifiers according to the third complex signal and the fourth complex signal, wherein the determining the third complex signal sent by the third RF transmitting circuit and the fourth complex signal sent by the fourth RF transmitting circuit according to the received data of the first RF receiving circuit by sequentially turning on the low noise amplifiers is specifically to iteratively perform the following steps N times: turn on the i-th low noise amplifier, control the eighth selection switch, the fourth selection switch, the seventh selection switch, and the fifth selection switch to switch so that the output end of the coupler of the third RF transmitting circuit and the fourth RF receiving circuit are connected to the two ends of the embedded transmission line, control the third RF transmitting circuit to send a fourth initial signal, and receive the third complex signal through the first RF receiving circuit, control the ninth selection switch, the fifth selection switch, the fourth selection switch, and the sixth selection switch to switch so that the output end of the coupler of the fourth RF transmitting circuit and the third RF receiving circuit are connected to the two ends of the embedded transmission line, control the fourth RF transmitting circuit to send a fourth initial signal, and receive the fourth complex signal through the first RF receiving circuit.

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