Calibration circuit and calibration method

Abstract

The embodiment of the application discloses a kind of calibration circuit and calibration method, by setting baseband unit in calibration circuit, with the baseband unit connection M group radio frequency circuit, it is configured as the combiner of output signal synthesis according to multiple input signals, it is configured as the distributor of multiple output signals according to one input signal equal division, analog beamforming circuit, select multiple selection switches to connect the radio frequency circuit with one of the combiner, distributor and analog beamforming circuit to form detection loop.It can be based on hardware to analog-digital hybrid beamforming large-scale array antenna calibration.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and more particularly to a calibration circuit and calibration method. Background Technology

[0002] Mobile base station calibration is a critical process to ensure the normal operation of base stations and optimize communication quality. The main purpose of base station calibration is to ensure that the radio frequency channels of the base station antenna system are consistent in amplitude and phase, thereby achieving accurate signal transmission and reception, improving communication quality, reducing signal interference and distortion, and optimizing the coverage of the base station.

[0003] Currently, there are two types of methods for mobile base station calibration: hardware-based calibration methods and air interface calibration methods. Compared with air interface calibration methods, hardware-based calibration methods have advantages such as saving air interface overhead, faster calibration speed, and being unaffected by spatial channel quality. However, existing hardware-based calibration methods are only applicable to fully digital beamforming structures and do not support hybrid analog-digital beamforming massive MIMO antennas. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a calibration circuit and a calibration method, thereby enabling hardware-based calibration of hybrid analog-to-digital beamforming large-scale array antennas.

[0005] In a first aspect, embodiments of the present invention provide a calibration circuit, the circuit comprising:

[0006] Baseband unit;

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

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

[0009] The distributor is configured to divide an input signal into multiple output signals equally.

[0010] Analog beamforming circuit;

[0011] Multiple selection switches are configured to select one of the radio frequency circuitry to connect to the combiner, distributor, and analog beamforming circuitry to form a detection loop.

[0012] Secondly, embodiments of the present invention provide a radio frequency system calibration method, the method specifically comprising:

[0013] The radio frequency system is calibrated according to the calibration circuit;

[0014] The calibration circuit includes:

[0015] Baseband unit;

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

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

[0018] The distributor is configured to divide an input signal into multiple output signals equally.

[0019] Analog beamforming circuit;

[0020] Multiple selection switches are configured to select one of the radio frequency circuitry to connect to the combiner, distributor, and analog beamforming circuitry to form a detection loop.

[0021] The technical solution of this invention includes 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 from multiple input signals, a distributor configured to divide an input signal into multiple output signals, an analog beamforming circuit, and multiple selection switches that connect the radio frequency circuits to one of the combiner, distributor, and analog beamforming circuit to form a detection loop. Thus, hardware-based calibration of a hybrid analog-to-digital beamforming massive MIMO antenna is possible. Attached Figure Description

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

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

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

[0025] Figure 3 This is a circuit diagram of the first calibration method used in an embodiment of the present invention.

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

[0027] Figure 5 This is a circuit diagram of the second calibration method used in an embodiment of the present invention.

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

[0029] Figure 7 This is a circuit diagram of the third calibration method used in an embodiment of the present invention.

[0030] Figure 8 This is a flowchart illustrating the adjustment of each power amplifier based on a first complex signal and a second complex signal according to an embodiment of the present invention.

[0031] Figure 9 This is a flowchart of the fourth calibration method according to an embodiment of the present invention;

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

[0033] Figure 11 This is another circuit diagram for calibration using the fourth calibration method in an embodiment of the present invention;

[0034] Figure 12 This is a flowchart of adjusting each low-noise amplifier according to the third complex signal and the fourth complex signal in an embodiment of the present invention. Detailed Implementation

[0035] The present application is described below based on embodiments, but it is not limited to these embodiments. In the detailed description of the present application below, certain specific details are described in detail. Those skilled in the art can fully understand the present application without these details. To avoid obscuring the substance of the present application, well-known methods, processes, flows, elements, and circuits are not described in detail.

[0036] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0037] Furthermore, it should be understood that in the following description, "circuit" refers to a conductive loop consisting of at least one element or sub-circuit connected by electrical or electromagnetic connections. When an element or circuit is said to be "connected" to another element or "connected" between two nodes, it can be directly coupled or connected to another element, or there may be intermediate elements. The connection between elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected" to another element, it means that there are no intermediate elements between them.

[0038] Unless the context explicitly requires it, words such as "including" or "contains" throughout the application should be interpreted as including rather than exclusive or exhaustive; that is, meaning "including but not limited to".

[0039] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, "a plurality of" means two or more.

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

[0041] The Building Baseband Unit (BBU) 1 is a unit in a telecommunications system that processes baseband signals. The BBU works in conjunction with the radio frequency (RF) circuit to achieve wireless signal transmission and processing. In this embodiment of the invention, the function of the BBU 1 is to control the RF circuit, the analog beamforming circuit 5, and multiple selection switches to form a detection loop. It transmits signals, receives signals from the RF circuit, analyzes and processes the signals from the RF circuit, and adjusts the complex gain of the RF circuit or the analog beamforming circuit based on the processing results.

[0042] The radio frequency (RF) circuit comprises M RF circuits, each including an RF transmitter (TX) and a receiver (RX). As shown in the figure, the i-th RF circuit includes an RF transmitter (TXi) and a receiver (RXi), i = 1, 2, ..., M. The RF transmitter processes the signal from the baseband unit into mid-to-high frequencies (including digital-to-analog conversion, mixing, and filtering) before transmission. The receiver receives the RF signal, processes it into intermediate-to-high frequencies (including filtering, mixing, and analog-to-digital conversion), and transmits it to the baseband unit. RF circuit 2 is connected to baseband unit 1. Combiner 3 and distributor 4 are connected to RF circuit 2 via multiple selection switches. Specifically, adjusting the operating states of the multiple selection switches changes the connection relationship between combiner 3 or distributor 4 and the RF circuit, thereby forming corresponding detection loops for appropriate calibration steps. The RF circuit includes a coupler 21, which transmits a signal from one circuit to another or distributes a signal among multiple circuits to ensure effective signal transmission and distribution.

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

[0044] The function of distributor 4 is to divide one input signal into multiple output signals. In this embodiment of the invention, the input terminal of distributor 4 is connected to the coupler output terminal of the first radio frequency transmitting circuit, and the output terminal is connected to M radio frequency receiving circuits. That is, one input signal is divided into multiple output signals, sent to each radio frequency 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 combining and splitting units 52, N parallel components, N circulators 54, and an antenna array. Each phase shift group includes M phase shifters 51, each connected to one of the M groups of radio frequency (RF) circuits 2 to receive signals transmitted by the RF circuits and to transmit signals amplified by a low-noise amplifier from the antenna array. Each power combining and splitting unit 52 is connected to one phase shifter 51 in the N phase shift groups. Each of the N parallel components specifically consists of a power amplifier (PA) and a low-noise amplifier (LNA). The power amplifier receives weak signals from the signal source and amplifies them to a sufficiently strong level to ensure that the signal does not lose information or fail to be properly recognized by the receiving device during transmission due to attenuation. It also amplifies the signal to reduce noise and distortion during transmission, thereby improving the overall signal transmission quality of the system. The low-noise amplifier amplifies weak signals to a level that can be processed by subsequent circuits or devices, ensuring effective signal transmission and processing. Circulator 54 is used to isolate the transmitted and received signals, ensuring unidirectional signal transmission. The antenna array consists of N antenna elements 55. By precisely controlling the excitation amplitude and phase of each element to form a directional beam, the directivity and gain of the signal transmission are enhanced to achieve efficient and reliable signal transmission and reception. Embedded transmission lines 56 next to the antenna elements are used to couple the signals of each antenna element for calibration.

[0046] In other words, the analog beamforming circuit 5 of this embodiment includes N links, each link including a phase shifter group, a power combiner / distributor 52, a parallel component, a circulator 54, and an antenna element 55. The phase shifter group, power combiner / distributor 52, parallel component, circulator 54, and antenna element 55 are connected in series. Taking the first link as an example, the first phase shifter group includes M phase shifters 51, each phase shifter 51 connected to an RF circuit. The first parallel component is connected to the first phase shifter group via a single-pole double-throw switch. The first circulator 54 is connected to the first parallel component, and the first antenna element 55 is connected to the first circulator 54.

[0047] It should be noted that the figure only shows the phase shifters 51 connected to the first and second RF circuits. In reality, each of the M RF circuits needs to be connected to N phase shifters. For example, the ellipsis on the right side of the Mth RF circuit actually represents its corresponding N phase shifters, indicated by ellipsis in the figure. Each phase shifting group in the figure only shows two phase shifters 51 connected, but it should actually connect M phase shifters, also indicated by ellipsis in the figure. Similarly, the remaining ellipsis represent antenna arrays and parallel components not shown in the figure, which will not be elaborated upon here.

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

[0049] The first selection switch K1 is configured to select the connection between the output of the first RF transmitter circuit coupler and one of the inputs of the combiner and the distributor.

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

[0051] M-3 third selection switches K3 respectively select the connection of the second group of RF circuits and the fifth to M groups of RF circuits. The i-th third selection switch is configured to select the connection of the i-th group of RF circuits to one of the output terminals of the i-th phase shifter and the distributor in the N phase shifter groups, i = 2, 5, 6, ..., M. 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 the connection of the second RF receiving circuit to one of the output terminals of K3b and the distributor, and K3b is configured to select the connection of the analog beamforming circuit to one of K3a and the second RF transmitting circuit.

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

[0053] The fifth selection switch K5 is configured to select connecting 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. K6a is configured to select one of the following connections: the third RF receiving circuit to the output of the distributor, K6b, and K4. K6b is configured to select one of the following connections: the analog beamforming circuit to the third RF transmitting circuit, and K6a. Therefore, the sixth selection switch K6 is configured to select one of the following connections: the third group of RF circuits to the distributor, the fourth selection switch, and 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. K7a is configured to select one of the following connections: the fourth RF receiving circuit and the output of the distributor, K7b, and K5. K7b is configured to select one of the following connections: the analog beamforming circuit and the fourth RF transmitting circuit and K7a. Therefore, the seventh selection switch K7 is configured to select one of the following connections: the fourth group of RF circuits and the distributor, the fifth selection switch, and the fourth phase shifter among the M phase shifters in the N phase shift groups.

[0056] The eighth selection switch K8 is configured to select the connection between the output of the third group of RF circuit couplers and one of the combiner and the fourth selection switch.

[0057] The ninth selection switch K9 is configured to select the connection between the output of the fourth group of RF circuit couplers and one of the combiner and the fifth selection switch.

[0058] By setting multiple selection switches K1-K9, and selectively connecting the RF circuit 2 to 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, thus realizing hardware-based self-calibration based on adding low-cost components to the circuit.

[0059] In this embodiment of the invention, the baseband unit 1 controls the radio frequency circuit, the analog beamforming circuit 5, and multiple selection switches to form different detection loops, thereby achieving calibration of the analog beamforming circuit and the digital beamforming circuit.

[0060] Figure 2This is a flowchart of the first calibration method according to an embodiment of the present invention. The execution entity is a baseband unit, and it is executed in the downlink time slot. This method is used to calibrate M radio frequency (RF) transmission circuits. Specifically, it equalizes the complex gains of all RF transmission circuits based on the complex gain of the first RF transmission circuit. Figure 2 As shown, the calibration method includes 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 connect the output of the first RF transmitter coupler to the input of the combiner; the eighth selection switch is controlled to connect the output of the third RF transmitter coupler to the input of the combiner; the ninth selection switch is controlled to connect the output of the fourth RF transmitter coupler to the input of the combiner; and the second selection switch is controlled to connect the first RF receiver circuit to the output of the combiner. The equivalent circuit diagram after switching the switches is as follows: Figure 3 As shown, by adjusting multiple selection switches, the input of the combiner is connected to the output of each RF transmitting circuit coupler, and the output is connected to the first RF receiving circuit, thereby enabling the transmission of signals transmitted by each RF transmitting circuit to the combiner.

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

[0064] Specifically, by activating the first radio frequency receiving circuit, the baseband unit is able to receive the signals sent by each radio frequency transmitting circuit from the combiner output received by the first radio frequency receiving circuit.

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

[0066] Specifically, each RF transmitting circuit and each power amplifier is powered on. The purpose of powering on the power amplifiers is not to affect the operation of other time-frequency resources within the same frame. For M RF circuits, 2M OFDM (Orthogonal Frequency Division Multiplexing) symbols and the center frequency are used as time-frequency resources. All RF transmitting circuits transmit pilot sequences. The combiner synthesizes the first signal based on the input signals of each RF transmitting circuit and transmits it to the baseband unit through the first RF receiving circuit.

[0067] Step S140: Determine the first complex gain of each radio frequency transmission circuit based on the first signal using a channel estimation algorithm.

[0068] Channel estimation algorithm is the process of estimating the model parameters of a hypothetical channel model from the received data. Specifically, the channel estimation algorithm determines which part of the first signal was transmitted by which radio frequency (RF) transmitting circuit, that is, it determines the signals transmitted by each RF transmitting circuit.

[0069] Specifically, the complex gain of each radio frequency transmission circuit is equivalent to the 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, thus obtaining the complex gain of each radio frequency transmission circuit.

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

[0071] The complex gain of the other RF transmitting circuits is equalized based on the complex gain of the first RF transmitting circuit. It should be noted that the equalization of complex gains does not necessarily have to be based on the first RF transmitting circuit; it can be based on any RF transmitting circuit. This embodiment of the invention does not impose any limitation on this.

[0072] Specifically, a first calibration coefficient is calculated based on 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 transmitting circuit is G. TM For the i-th radio frequency transmitting circuit, since its complex gain is G Ti The first calibration coefficient of the i-th radio frequency transmitting circuit is determined to be G. Ti / G T1 Specifically, the complex gain of the i-th RF transmitting circuit is divided by its first calibration coefficient, and the adjusted complex gain of the i-th RF transmitting circuit is G. T1 That is, the complex gain of all RF transmitting circuits is adjusted to G. T1 This achieved the alignment of the complex gain of the RF transmission circuit and completed the calibration of the RF transmission circuit.

[0073] In summary, this calibration method first powers on all RF transmitting circuits and power amplifiers. Then, by switching the first, eighth, and ninth selection switches, the input of the combiner is connected to each RF transmitting circuit, and the output is connected to the first RF receiving circuit. Next, pilot sequences are transmitted through all RF transmitting circuits. The baseband unit receives the pilot sequences from the first RF receiving circuit and executes a channel estimation algorithm to obtain the complex gain of each RF transmitting circuit. Finally, alignment is performed using the first RF transmitting circuit as a reference.

[0074] This invention, through the inclusion of a baseband unit in the calibration circuit, connects M groups of radio frequency (RF) circuits to the baseband unit. These circuits are configured as a combiner to synthesize output signals from multiple input signals, a distributor to equally divide an input signal into multiple output signals, an analog beamforming circuit, and multiple selection switches to connect the RF circuits to one of the combiner, distributor, and analog beamforming circuit to form a detection loop. Thus, hardware-based calibration of hybrid analog-to-digital beamforming massive MIMO antennas is possible.

[0075] Figure 4 This is a flowchart of the second calibration method according to an embodiment of the present invention. The execution entity is a baseband unit, and it is executed in the uplink time slot. This method is used to calibrate M RF receiving circuits. Specifically, it aligns the complex gains of all RF receiving circuits based on the complex gain of the first RF receiving circuit. Figure 4 As shown, the calibration method includes 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 connect the first RF transmitting circuit to the input of the distributor; the second selection switch is controlled to connect the first RF receiving circuit to the output of the distributor; the third selection switch is controlled to connect the second, fifth, sixth, ... Mth RF receiving circuits to the output of the combiner; the sixth selection switch is controlled to connect the third RF receiving circuit to the output of the combiner; and the seventh selection switch is controlled to connect the fourth RF receiving circuit to the output of the combiner. The specific circuit diagram after switching the switches is shown below. Figure 5 As shown, by adjusting multiple selection switches, the input of the distributor is connected to the first RF transmitting circuit, and the output is connected to each RF receiving circuit, thus distributing the signal transmitted 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 radio frequency (RF) receiving circuit, the baseband unit is able to receive signals received by each RF receiving circuit. Simultaneously, each low-noise amplifier is powered down to prevent signal interference from the antenna array.

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

[0081] The second initial signal consists of two 1-bit bits with a phase of 0. Specifically, the first radio frequency (RF) transmitting circuit occupies two symbols and all frequency time-frequency resources, transmitting two 1-bit bits with a phase of 0. The second initial signal, after passing through each RF circuit, is received by the baseband unit.

[0082] Step S240: Determine the second complex gain of each radio frequency receiving circuit based on the second signal.

[0083] After the baseband unit receives the second signal after passing through each RF circuit, it determines the second complex gain of the corresponding RF receiving circuit based on the second signal.

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

[0085] Specifically, after calculating the second complex gain of each RF receiving circuit, a second calibration coefficient is calculated based on the second complex gain. Then, the baseband unit adjusts the RF receiving circuit according to the calibration coefficient to achieve alignment. Similar to the adjustment method in the first calibration method, the embodiments of the present invention will not be described in detail here.

[0086] In summary, this calibration method first activates each RF receiving circuit and powers down each low-noise amplifier. Then, by switching the first, second, third, sixth, and seventh selection switches, the input of the distributor is connected to the first RF transmitting circuit, and the output is connected to each RF receiving circuit. Next, two bits of 1 are transmitted through the first RF transmitting circuit. The baseband unit receives signals from each RF receiving circuit and obtains the complex gain of each circuit. Finally, alignment is performed using the first RF receiving circuit as a reference.

[0087] This invention, through the inclusion of a baseband unit in the calibration circuit, connects M groups of radio frequency (RF) circuits to the baseband unit. These circuits are configured as a combiner to synthesize output signals from multiple input signals, a distributor to equally divide an input signal into multiple output signals, an analog beamforming circuit, and multiple selection switches to connect the RF circuits to one of the combiner, distributor, and analog beamforming circuit to form a detection loop. Thus, hardware-based calibration of hybrid analog-to-digital beamforming massive MIMO antennas is possible.

[0088] Figure 6 This is a flowchart of the third calibration method according to an embodiment of the present invention. The execution entity is a baseband unit, and it is executed in the downlink time slot. This method is used to calibrate the gains of N power amplifiers. Specifically, it aligns the complex gains of all power amplifiers based on the complex gain of the first power amplifier. Figure 6 As shown, the calibration method includes the following steps:

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

[0090] Specifically, the fourth and sixth selection switches are controlled to connect the third RF receiving circuit to one end of the antenna array embedded transmission line, and the fifth and seventh selection switches are controlled to connect the fourth RF receiving circuit to the other end of the antenna array embedded transmission line. The specific circuit diagram after switching is shown below. Figure 7 As shown. By adjusting multiple selection switches, the output of the antenna array can be connected to each radio frequency receiving circuit.

[0091] Step S320: Activate the third and fourth radio frequency receiving circuits.

[0092] Specifically, by activating the third and fourth radio frequency receiving circuits, the third and fourth radio frequency receiving circuits are enabled to receive signals.

[0093] Step S330: Sequentially turn on each power amplifier 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.

[0094] Specifically, this step involves iteratively executing steps S331-S333 N times, where:

[0095] Step S331: Turn on the i-th power amplifier.

[0096] Since the process involves N cycles, the first power amplifier is turned on during the first cycle, the second power amplifier is turned on during the second cycle, and so on, turning on all N power amplifiers sequentially. Specifically, the power amplifiers are turned on by switching the selector switch on the parallel component to the parallel branch containing the power amplifier and then powering on the power amplifier. Figure 7 This is a schematic diagram of the first power amplifier after it is turned on according to an embodiment of the present invention.

[0097] Step S332: Control the first radio frequency transmitting circuit to send the third initial signal to the i-th power amplifier.

[0098] Specifically, the first cycle is described, where the first power amplifier is turned on, and the other power amplifiers are not working. The first RF transmitting circuit occupies two symbols and all frequency time-frequency resources to transmit the third initial signal through the first power amplifier to the first antenna element. The third initial signal can be a two-bit 1 signal with both phases at 0, or it can be other types of signals; this embodiment of the invention does not impose any limitations on this. The third initial signal is coupled through an embedded transmission line (ETL) and transmitted to the third and fourth RF receiving circuits. The embedded transmission line is a special cable or structure used to transmit RF signals, ensuring stable signal transmission in the RF circuit by efficiently transmitting high-frequency signals. In RF circuits, due to the high frequency of the signal, a transmission line with specific impedance and transmission characteristics is required to ensure signal integrity.

[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, taking the first loop as an example, after the third initial signal is coupled through the embedded transmission line and sent to the third and fourth RF circuits, since the third initial signal is a two-bit 1 signal with both phases at 0, the baseband unit determines the first complex signal of the two bits received from the third RF receiving circuit and averages the two bits to obtain V1. Correspondingly, the baseband unit determines the second complex signal of the two bits received from the fourth RF receiving circuit and averages the two bits 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 amplitude information and phase information need to be aligned.

[0102] Through N iterations of steps S331-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, based on the N sets of first complex signals V obtained in the N iterations of step S330... i Second complex signal W i Determine the power amplifiers PA1, PA2...PA N The adjustment method is to adjust the gain difference of each power amplifier through the baseband unit.

[0105] Specifically, the adjustment parameters are calculated using the first complex signal and the 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 Let a be the first correlation parameter between the i-th power amplifier and the (i+1)-th power amplifier. t,1i Let β be the gain of the i-th power amplifier, where the subscript 1 in i indicates that the calibration signal comes from the first RF transmitting circuit. t i,i+1 Let arg(β) be the gain ratio of the (i+1)th power amplifier to the ith power amplifier. t i,i+1 ) is a complex number β t i,i+1 The principal argument value, mag_db(β) t i,i+1 ) is β t i,i+1 The decibel value.

[0111] Figure 8 This is a flowchart of a method for adjusting various power amplifiers based on 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 sets of first correlation parameters based on the first complex signal and the second complex signal.

[0113] Specifically, using formula (1), the first correlation parameters between the first power amplifier and the second power amplifier, the first correlation parameters between the second power amplifier and the third power amplifier, ... the first correlation parameters between the (N-1)th power amplifier and the Nth power amplifier are calculated based on the first complex signal and the second complex signal, respectively.

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

[0115] Specifically, the adjacent gain ratio of the i-th power amplifier is the gain ratio of the i-th power amplifier to the (i-1)-th power amplifier. Therefore, determining the adjacent gain ratio of N-1 power amplifiers essentially involves calculating the gain ratio of the second power amplifier to the first, the third power amplifier to the second, ..., the Nth power amplifier to the (N-1)-th power amplifier, and using these as the adjacent gain ratios for the second, third, ..., Nth power amplifiers.

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

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

[0118] Specifically, the gain ratios of the second, third, ..., and Nth power amplifiers with the first power amplifier are calculated according to formula (5). For general considerations, the i-th (i>1) power amplifier is used as an example. As can be seen from formula (5), the gain ratio of the i-th power amplifier with the first power amplifier is actually equal to the product of the adjacent gain ratios of the second, third, ..., i-th power amplifiers. The adjacent gain ratio of the j-th power amplifier is approximately equal to the first correlation parameter of the j-th power amplifier with the (j-1)-th power amplifier. Therefore, the gain ratio of the i-th power amplifier with the first power amplifier can actually be approximated by multiplying the first power amplifier with the first correlation parameter of the second power amplifier, the second power amplifier and the third power amplifier, ..., the (i-1)-th power amplifier with 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 calculating the gain ratio of each power amplifier to the first power amplifier, the complex gains of the other power amplifiers are aligned based on the complex gain of the first power amplifier. The alignment method is similar to that in the first calibration method, and will not be elaborated further in this embodiment.

[0121] This invention, through the inclusion of a baseband unit in the calibration circuit, connects M groups of radio frequency (RF) circuits to the baseband unit. These circuits are configured as a combiner to synthesize output signals from multiple input signals, a distributor to equally divide an input signal into multiple output signals, an analog beamforming circuit, and multiple selection switches to connect the RF circuits to one of the combiner, distributor, and analog beamforming circuit to form a detection loop. Thus, hardware-based calibration of hybrid analog-to-digital beamforming massive MIMO antennas is possible.

[0122] In summary, this calibration method first powers on the first RF transmitting circuit and the first power amplifier. Then, by switching the fourth, fifth, sixth, and seventh selection switches, the third and fourth RF receiving circuits are connected to both sides of the embedded transmission line, activating them. Next, the first RF transmitting circuit transmits two bits of 1, which are amplified by the first power amplifier, reach the first antenna element, couple through the embedded transmission line, and are received by the third RF receiving circuit and sent to the baseband unit to obtain V1. The fourth RF receiving circuit receives these bits and sends them to the baseband unit to obtain W1. This process is repeated to obtain V. i and W i (i = 2, 3, ..., N). Finally, according to V i and W i Obtain the gain ratio of each power amplifier to the first power amplifier, and then equalize the gain of each power amplifier based on the gain ratio.

[0123] Figure 9 This is a flowchart of the fourth calibration method according to an embodiment of the present invention. The execution entity is a baseband unit, and it is executed in the uplink time slot. This method is used to calibrate the gain of N low-noise amplifiers. Specifically, it aligns the complex gains of all low-noise amplifiers based on the complex gain of the first low-noise amplifier, such as... Figure 9 As shown, the calibration method includes the following steps:

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

[0125] Specifically, by activating the first radio frequency receiving circuit, the baseband unit is able to receive signals transmitted by the third and fourth radio frequency circuits that were received by the first radio frequency receiving circuit.

[0126] Step S420: By sequentially turning on the low-noise amplifier, determine the third complex signal transmitted by the third radio frequency transmitting circuit and the fourth complex signal transmitted by the fourth radio frequency transmitting circuit based on the received data of the first radio frequency receiving circuit.

[0127] Specifically, this step involves iteratively executing steps S421-S427 N times, where:

[0128] Step S421: Turn on the i-th low-noise amplifier.

[0129] Specifically, in the first loop, the first low-noise amplifier is turned on; in the second loop, the second low-noise amplifier is turned on; and so on, turning on N low-noise amplifiers 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 both ends of the antenna array embedded transmission line, and activate the fourth RF receiving circuit.

[0131] Taking the activation of the first low-noise amplifier as an example, specifically, the fourth and eighth selection switches are controlled to connect the output of the third RF transmitting circuit coupler to one end of the antenna array embedded transmission line, and the fifth and seventh selection switches are controlled to connect the fourth RF receiving circuit to the other end of the antenna array embedded transmission line, forming a loop through the antenna array embedded transmission line. The specific circuit is as follows: Figure 10 As shown. 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 radio frequency transmitting circuit to send the fourth initial signal to the antenna array embedded transmission line, and the other end is received by the fourth radio frequency receiving circuit.

[0133] Specifically, after the third radio frequency transmitting circuit is connected to one end of the embedded transmission line of the antenna array, the third radio frequency transmitting circuit is controlled to transmit a fourth initial signal. In an optional implementation, the fourth initial signal is a bit 1 with both phases being 0.

[0134] Step S424: Receive the third complex signal that is coupled from the embedded transmission line to the first antenna element and amplified by the first low-noise amplifier through the first radio frequency receiving circuit;

[0135] The fourth initial signal, received by the first RF receiving circuit and transmitted by the third RF transmitting circuit, is coupled from the i-th antenna element to the embedded transmission line and then to the third complex signal P after being amplified by the i-th low-noise amplifier. i Therefore, through N iterations, the third complex signal P1, P2...P1 is obtained sequentially through N antenna elements and N low-noise amplifiers. N .

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

[0137] Specifically, the fifth and ninth selection switches are controlled to connect the output of the fourth RF transmitting circuit coupler to one end of the antenna array embedded transmission line, and the fourth and sixth selection switches are controlled to connect the third RF receiving circuit to the other end of the antenna array embedded transmission line, forming a loop through the antenna array embedded transmission line. The specific circuit is as follows: Figure 11 As shown. 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 send the fourth initial signal to one end of the antenna array embedded transmission line.

[0139] Similar to step S423, it will not be described in detail here.

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

[0141] Similar to step S424, the fourth initial signal received by the first RF receiving circuit and transmitted by the fourth RF transmitting circuit is coupled from the embedded transmission line through the i-th antenna element to the fourth complex signal Q after being amplified by the i-th low-noise amplifier. i After N cycles, the fourth initial signal transmitted by the fourth RF transmitting circuit is sequentially transformed into the fourth complex signal Q1, Q2...Q1 by N antenna elements and N low-noise amplifiers. N .

[0142] In summary, the third complex signal P1, P2...P was obtained through N iterations of steps S421-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, based on the N sets of third complex signals P obtained in the N iterations of steps S421-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 parameters are calculated using the third and fourth complex signals according to the following formula:

[0146]

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

[0148]

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

[0150] Figure 12 This is a flowchart of a method for adjusting each low-noise amplifier according to the third complex signal and the fourth complex signal, as described in an embodiment of the present invention. Figure 12 As shown, the method for adjusting each low-noise amplifier specifically includes:

[0151] Step S431: Calculate N-1 sets of second correlation parameters based on the third complex signal and the fourth complex signal.

[0152] Specifically, using formula (6), the second correlation parameters of the first low-noise amplifier and the second low-noise amplifier, the second correlation parameters of the second low-noise amplifier and the third low-noise amplifier, ... the second correlation parameters of the (N-1)th low-noise amplifier and the Nth low-noise amplifier are calculated based on the third complex signal and the fourth complex signal, respectively.

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

[0154] Specifically, the adjacent gain ratio of the i-th low-noise amplifier is the gain ratio of the i-th low-noise amplifier to the (i-1)-th low-noise amplifier. Therefore, determining the adjacent gain ratio of N-1 low-noise amplifiers essentially involves calculating the gain ratio of the second low-noise amplifier to the first, the third low-noise amplifier to the second, ..., the gain ratio of the N-th low-noise amplifier to the (N-1)-th low-noise amplifier, and using these as the adjacent gain ratios for the second, third, ..., N-th low-noise amplifiers.

[0155] 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 correlation parameters. Specifically, taking the second low-noise amplifier as an example, it can be seen from formulas (7) and (8) that the gain ratio of the second low-noise amplifier to the first low-noise amplifier is approximately equal to the second correlation parameters of the first low-noise amplifier to the second low-noise amplifier. That is, the gain ratio can be replaced by the second correlation parameters for subsequent calculations.

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

[0157] Specifically, the gain ratios of the second, third, ..., and Nth low-noise amplifiers with the first low-noise amplifier are calculated according to formula (10). For general considerations, the i-th (i>1) low-noise amplifier is used as an example. As can be seen from formula (10), the gain ratio of the i-th low-noise amplifier with the first low-noise amplifier is actually equal to the product of the adjacent gain ratios of the second, third, ..., i-th low-noise amplifiers. The adjacent gain ratio of the j-th low-noise amplifier is approximately equal to the second correlation parameter of the j-th low-noise amplifier with the (j-1)-th low-noise amplifier. Therefore, the gain ratio of the i-th low-noise amplifier with the first low-noise amplifier can actually be approximated by the cumulative product of the second correlation parameter of the first low-noise amplifier with the second, third, ..., i-1-th low-noise amplifiers with the i-th low-noise amplifier.

[0158] Step S434: Adjust each low-noise amplifier according to the gain ratio of each low-noise amplifier to the first low-noise amplifier.

[0159] Specifically, after calculating the gain ratio of each low-noise amplifier to the first low-noise amplifier, the complex gains of the other low-noise amplifiers are aligned based on the complex gain of the first low-noise amplifier. Similar to the alignment method in the first calibration method, this embodiment of the invention will not elaborate further.

[0160] In summary, this calibration method first activates the first RF receiving circuit and powers on the first low-noise amplifier. By controlling the fourth, fifth, seventh, and eighth selection switches, 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, and the third RF transmitting circuit and the fourth RF receiving circuit are activated. Two bits of 1 are transmitted through the third RF transmitting circuit to one end of the antenna array embedded transmission line, and the other end is received by the fourth RF receiving circuit. The P1 signal, coupled from the first antenna element to the embedded transmission line and amplified by the first low-noise amplifier, is obtained in the first RF receiving circuit. Similarly, the fourth RF transmitting circuit and the third RF transmitting circuit are connected to the two ends of the embedded transmission line to form a loop, and two bits of 1 are transmitted through the fourth RF transmitting circuit, obtaining the Q1 signal in the first RF receiving circuit. By repeating the above steps and sequentially powering on the i-th low-noise amplifier, P1 is obtained. i and Q i (i = 2, 3, ..., N). Finally, according to P i and Q i Obtain the gain ratio of each low-noise amplifier to the first low-noise amplifier, and then align each low-noise amplifier according to the gain ratio.

[0161] This invention, through the inclusion of a baseband unit in the calibration circuit, connects M groups of radio frequency (RF) circuits to the baseband unit. These circuits are configured as a combiner to synthesize output signals from multiple input signals, a distributor to equally divide an input signal into multiple output signals, an analog beamforming circuit, and multiple selection switches to connect the RF circuits to one of the combiner, distributor, and analog beamforming circuit to form a detection loop. Thus, hardware-based calibration of hybrid analog-to-digital beamforming massive MIMO antennas is possible.

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

[0163] The following explanation uses the calibration of the RF transmitter across all frequencies as an example; the calibration of the RF receiver circuit, power amplifier, and low-noise amplifier across all frequencies is similar. First, the first RF transmitter circuit is powered on. The first selection switch is switched to connect the first RF transmitter circuit to the input of the combiner, and the second selection switch is switched to connect the first RF receiver circuit to the output of the combiner. Then, occupying all frequencies within the 2-symbol and system frequency band time-frequency resources, the first RF transmitter circuit transmits two bits of 1 with phase 0 at L frequency points. The baseband unit receives the carrier pilot signals from the first RF receiver circuit. For each frequency point, two data points are received. The two data points at each frequency point are averaged to obtain the gain G. T1,l (l = 1, 2...L). Power on the other M-1 RF transmitting circuits and their corresponding power amplifiers sequentially, and obtain G by connecting the RF transmitting circuits to the input of the combiner and the first RF receiving circuit to the output of the combiner in the same way. Tj，l (l = 1, 2...L, j = 2, 3...M). Where G... Tj,l This represents the gain of the j-th RF transmitting circuit at frequency l.

[0164] Specifically, calculating the calibration coefficient involves calculating the ratio of the gain of the j-th RF transmitting circuit at frequency l to the gain of the first RF transmitting circuit at the center frequency (L / 2), using the following formula:

[0165]

[0166] In the above formula, the numerator on the right side of the multiplication sign is the gain ratio of the j-th RF transmitting circuit to the first RF transmitting circuit, calculated in the main process. The numerator on the left side of the multiplication sign is the gain of the j-th RF transmitting circuit at frequency l, and the denominator is the gain of the j-th RF transmitting circuit at the center frequency. These two values ​​can be obtained when the j-th RF transmitting circuit is powered on with its corresponding power amplifier. After calculating the calibration coefficients, the gains of each RF circuit at each frequency are calibrated according to these coefficients.

[0167] Those skilled in the art will understand that embodiments of this application can be provided as methods, apparatus (devices), or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied 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] This application is described with reference to flowchart illustrations of methods, apparatus (devices), and computer program products according to embodiments of this application. It should be understood that each step in the flowchart can be implemented by computer program instructions.

[0169] These computer program instructions may be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including an instruction means, the implementation process of which is described in the instruction means. Figure 1 The function specified in one or more processes.

[0170] These computer program instructions may also be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing device, produce instructions for implementing processes. Figure 1 A device for a function specified in one or more processes.

[0171] Another embodiment of the present invention relates to a non-volatile storage medium for storing a computer-readable program for use by a computer to execute some or all of the above-described method embodiments.

[0172] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program specifying the relevant hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0173] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A calibration circuit for calibrating a hybrid analog-to-digital beamforming massive duct antenna, characterized in that, The circuit includes: Baseband unit; M groups of radio frequency circuits are connected to the baseband unit, and the radio frequency circuits include radio frequency transmitting circuits and radio frequency receiving circuits; The combiner is configured to synthesize an output signal based on multiple input signals; The distributor is configured to divide an input signal into multiple output signals equally. Analog beamforming circuit; Multiple selection switches are configured to select one of the radio frequency circuitry to connect to the combiner, distributor, and analog beamforming circuitry to form a detection loop; The analog beamforming circuit includes: There are 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; Embedded transmission line; N power combining and dividing units are connected to N phase shifting groups respectively; N parallel components are connected to N power combining and dividing units respectively. Each parallel component includes a power amplifier and a low-noise amplifier connected in parallel. N circulators are connected to N parallel components respectively; An antenna array, comprising N antenna elements, is connected to N circulators respectively; The plurality of selection switches include: A first selection switch is configured to select the connection of the first radio frequency transmitting circuit to one of the inputs of the combiner and the distributor. The second selection switch is configured to select one of the following connections: the first group of radio frequency circuits, the first phase shifter in the N phase shifter groups, the output of the combiner, and the output of the distributor. M-3 third selection switches are used to select the connection of the second group of RF circuits and the fifth to M groups of RF circuits, respectively. The i-th third selection switch is configured to select the connection of the i-th group of RF circuits to one of the output terminals of the i-th phase shifter and the distributor in the N phase shift groups, i=2,5,6,...,M; A fourth selection switch is configured to select connecting one end of the embedded transmission line to one of the third RF receiving circuit and the third RF transmitting circuit; The fifth selection switch is configured to select connecting one end of the embedded transmission line to one of the fourth RF receiving circuit and the fourth RF transmitting circuit; The sixth selection switch is configured to select to connect the third group of radio frequency circuitry to one of the distributor, the fourth selection switch, and the third phase shifter in the N phase shift groups; The seventh selection switch is configured to select to connect the fourth group of radio frequency circuitry to one of the distributor, the fifth selection switch, and the fourth phase shifter in the N phase shift groups; The eighth selection switch is configured to select the connection of the third radio frequency transmitting circuit to one of the combiner and the fourth selection switch; The ninth selection switch is configured to select the connection of the fourth radio frequency transmitting circuit to one of the combiner and the fifth selection switch; The baseband unit is configured to control the switching of the first selection switch, the second selection switch, the eighth selection switch and the ninth selection switch so that each of the radio frequency transmitting circuits and the first radio frequency receiving circuit are connected to the combiner for calibrating the M radio frequency transmitting circuits. 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 to connect the first radio frequency transmitting circuit and each radio frequency receiving circuit to the distributor for calibrating the M radio frequency receiving circuits; The baseband unit is configured to control the fourth, fifth, sixth, and seventh selection switches to connect the third and fourth RF receiving circuits to both ends of the embedded transmission line for calibrating the gain of N power amplifiers. The baseband unit is configured to control the fourth and eighth selection switches to connect the output of the third RF transmitting circuit coupler to one end of the antenna array embedded transmission line, control the fifth and seventh selection switches to connect the fourth RF receiving circuit to the other end of the antenna array embedded transmission line, control the fifth and ninth selection switches to connect the output of the fourth RF transmitting circuit coupler to one end of the antenna array embedded transmission line, and control the fourth and sixth selection switches to connect the third RF receiving circuit to the other end of the antenna array embedded transmission line, for calibrating the gain of N low-noise amplifiers.

2. The calibration circuit according to claim 1, characterized in that, The baseband unit is configured to activate each radio frequency receiving circuit, control the first radio frequency transmitting circuit to send a second initial signal to the distributor, output a second signal through each radio frequency receiving circuit, determine the second complex gain of each radio frequency receiving circuit based on the second signal, and adjust the radio frequency receiving circuit based on the second complex gain.

3. The calibration circuit according to claim 1, characterized in that, The baseband unit is configured to activate the first radio frequency receiving circuit, control each radio frequency transmitting circuit to send a first initial signal to the combiner, which then passes through the first radio frequency receiving circuit to output a first signal. The first complex gain of each radio frequency transmitting circuit is determined based on the first signal using a channel estimation algorithm, and the radio frequency transmitting circuit is adjusted based on the first complex gain. The channel estimation algorithm is a method for estimating the model parameters of a hypothetical channel model from the received data.

4. The calibration circuit according to claim 1, characterized in that, The baseband unit is configured to activate the third and fourth radio frequency receiving circuits, and to sequentially turn on each power amplifier by controlling a switch to determine the first complex signal received by the third radio frequency receiving circuit and the second complex signal received by the fourth radio frequency receiving circuit. The power amplifiers are adjusted according to the first and second complex signals. Specifically, determining the first complex signal received by the third radio frequency receiving circuit and the second complex signal received by the fourth radio frequency receiving circuit involves iteratively executing the following steps N times: turning on the j-th power amplifier, controlling the first radio frequency transmitting circuit to send a third initial signal to the j-th power amplifier, and determining the first complex signal received by the third radio frequency receiving circuit and the second complex signal received by the fourth radio frequency receiving circuit.

5. The calibration circuit according to claim 1, characterized in that, The baseband unit is configured to activate the first radio frequency receiving circuit, and determine the third complex signal transmitted by the third radio frequency transmitting circuit and the fourth complex signal transmitted by the fourth radio frequency transmitting circuit based on the received data of the first radio frequency receiving circuit by sequentially turning on the low noise amplifiers. The low noise amplifiers are then adjusted based on the third and fourth complex signals. Specifically, determining the third complex signal transmitted by the third radio frequency transmitting circuit and the fourth complex signal transmitted by the fourth radio frequency transmitting circuit based on the received data of the first radio frequency receiving circuit by sequentially turning on the low noise amplifiers involves iteratively executing the following steps N times: turning on the j-th low noise amplifier; controlling the eighth, fourth, seventh, and fifth selection switches to connect the third radio frequency transmitting circuit and the fourth radio frequency receiving circuit to both ends of the embedded transmission line; controlling the third radio frequency transmitting circuit to transmit the fourth initial signal; receiving the third complex signal through the first radio frequency receiving circuit; controlling the ninth, fifth, fourth, and sixth selection switches to connect the fourth radio frequency transmitting circuit and the third radio frequency receiving circuit to both ends of the embedded transmission line; controlling the fourth radio frequency transmitting circuit to transmit the fourth initial signal; receiving the fourth complex signal through the first radio frequency receiving circuit.

6. A calibration method, applicable to calibration circuits, for calibrating mixed-signal beamforming large-scale array antennas, characterized in that, The calibration circuit includes a baseband unit, M groups of RF circuits, a combiner, a distributor, an analog beamforming circuit, and multiple selection switches. The M groups of RF circuits are connected to the baseband unit. The combiner is configured to synthesize an output signal based on multiple input signals, and the distributor is configured to equally divide an input signal into multiple output signals. The method includes: By controlling the plurality of selection switches, the radio frequency circuit is connected to one of the combiner, distributor and analog beamforming circuit to form a detection loop; The analog beamforming circuit includes: There are 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; Embedded transmission line; N power combining and dividing units are connected to N phase shifting groups respectively; N parallel components are connected to N power combining and dividing units respectively. Each parallel component includes a power amplifier and a low-noise amplifier connected in parallel. N circulators are connected to N parallel components respectively; An antenna array, comprising N antenna elements, is connected to N circulators respectively; The plurality of selection switches include: A first selection switch is configured to select the connection of the first radio frequency transmitting circuit to one of the inputs of the combiner and the distributor. The second selection switch is configured to select one of the following connections: the first group of radio frequency circuits, the first phase shifter in the N phase shifter groups, the output of the combiner, and the output of the distributor. M-3 third selection switches are used to select the connection of the second group of RF circuits and the fifth to M groups of RF circuits, respectively. The i-th third selection switch is configured to select the connection of the i-th group of RF circuits to one of the output terminals of the i-th phase shifter and the distributor in the N phase shift groups, i=2,5,6,...,M; A fourth selection switch is configured to select connecting one end of the embedded transmission line to one of a third RF receiving circuit and a third RF transmitting circuit; The fifth selection switch is configured to select connecting one end of the embedded transmission line to one of the fourth RF receiving circuit and the fourth RF transmitting circuit; The sixth selection switch is configured to select to connect the third group of radio frequency circuitry to one of the distributor, the fourth selection switch, and the third phase shifter in the N phase shift groups; The seventh selection switch is configured to select to connect the fourth group of radio frequency circuitry to one of the distributor, the fifth selection switch, and the fourth phase shifter in the N phase shift groups; The eighth selection switch is configured to select to connect the third group of radio frequency circuitry to one of the combiner and the fourth selection switch; The ninth selection switch is configured to select the connection of the fourth group of radio frequency circuits to one of the combiner and the fifth selection switch; The step of controlling the plurality of selection switches to connect the radio frequency circuit to one of the combiner, distributor, and analog beamforming circuit to form a detection loop includes: The first selection switch, the second selection switch, the eighth selection switch, and the ninth selection switch are controlled to switch so that each radio frequency transmitting circuit and the first radio frequency receiving circuit are connected to the combiner for calibration of M radio frequency transmitting circuits; The first selection switch, the second selection switch, the third selection switch, the sixth selection switch, and the seventh selection switch are controlled to switch so that the first radio frequency transmitting circuit and each radio frequency receiving circuit are connected to the distributor for calibration of M radio frequency receiving circuits; The fourth, fifth, sixth, and seventh selection switches are controlled to connect the third and fourth RF receiving circuits to both ends of the embedded transmission line for calibrating the gain of N power amplifiers. The fourth and eighth selection switches are controlled to connect the output of the third RF transmitting circuit coupler to one end of the antenna array embedded transmission line; the fifth and seventh selection switches are controlled to connect the fourth RF receiving circuit to the other end of the antenna array embedded transmission line; the fifth and ninth selection switches are controlled to connect the output of the fourth RF transmitting circuit coupler to one end of the antenna array embedded transmission line; and the fourth and sixth selection switches are controlled to connect the third RF receiving circuit to the other end of the antenna array embedded transmission line. This is used to calibrate the gain of N low-noise amplifiers.

7. The method according to claim 6, characterized in that, The step of controlling the plurality of selection switches to select one of the radio frequency circuits to connect to the combiner, the distributor, and the analog beamforming circuit to form a detection loop further includes: The first radio frequency receiving circuit is activated, and each radio frequency transmitting circuit is controlled to send a first initial signal to the combiner. The combined circuit then passes through the first radio frequency receiving circuit to output a first signal. A channel estimation algorithm is used to determine the first complex gain of each radio frequency transmitting circuit based on the first signal. The radio frequency transmitting circuits are then adjusted based on the first complex gain. The channel estimation algorithm is a method for estimating model parameters of a hypothetical channel model from the received data; or... Activate each RF receiving circuit, control the first RF transmitting circuit to send a second initial signal to the distributor, and output a second signal through each RF receiving circuit. Determine the second complex gain of each RF receiving circuit based on the second signal, and adjust the RF receiving circuit according to the second complex gain; or Activate the third and fourth RF receiving circuits, and sequentially turn on each power amplifier via a control 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. Adjust each power amplifier according to the first and second complex signals. Specifically, determining the first complex signal received by the third RF receiving circuit and the second complex signal received by the fourth RF receiving circuit involves iteratively executing the following steps N times: turn on the j-th power amplifier, control the first RF transmitting circuit to send a third initial signal to the j-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 receiving circuit, or... Activate the first RF receiving circuit, and determine the third complex signal transmitted by the third RF transmitting circuit and the fourth complex signal transmitted by the fourth RF transmitting circuit based on the received data of the first RF receiving circuit by sequentially turning on the low-noise amplifiers. Adjust each of the low-noise amplifiers according to the third complex signal and the fourth complex signal. Specifically, determining the third complex signal transmitted by the third RF transmitting circuit and the fourth complex signal transmitted by the fourth RF transmitting circuit based on the received data of the first RF receiving circuit by sequentially turning on the low-noise amplifiers involves iteratively executing the following steps N times: turn on the j-th low-noise amplifier, control the eighth, fourth, seventh, and fifth selection switches to switch so that the third RF transmitting circuit and the fourth RF receiving circuit are connected to both ends of the embedded transmission line, control the third RF transmitting circuit to transmit the fourth initial signal, receive the third complex signal through the first RF receiving circuit, control the ninth, fifth, fourth, and sixth selection switches to switch so that the fourth RF transmitting circuit and the third RF receiving circuit are connected to both ends of the embedded transmission line, control the fourth RF transmitting circuit to transmit the fourth initial signal, and receive the fourth complex signal through the first RF receiving circuit.

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