Digital predistortion circuit and antenna device

Abstract

The present disclosure provides a digital predistortion circuit, comprising: a first coupling line structure used for coupling output ends of a plurality of sub-transmission channels of an antenna circuit, wherein each sub-transmission channel is used for generating an output radio frequency signal at the respective output end thereof on the basis of an input digital signal; and a processing module connected to the first coupling line structure and used for carrying out predistortion on the basis of a signal from the first coupling line structure. The present disclosure further provides an antenna device.

Description

Digital predistortion circuit, antenna device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202410042734.X filed on January 11, 2024, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates to the technical field of digital predistortion (DPD), and in particular to a DPD circuit and an antenna device. Background Art

[0004] The performance of the antenna device can be improved by digital pre-distortion (DPD).

[0005] However, the DPD in related technologies cannot be performed "online", the DPD effect is poor, or a large number of devices (such as multiple couplers) need to be added to the antenna device, which has a complex structure and high cost.

[0006] Public content

[0007] The present disclosure provides a DPD circuit and an antenna device.

[0008] In a first aspect, the present disclosure provides a DPD circuit, comprising: a first coupling line structure for coupling the output ends of multiple sub-transmitting channels of an antenna circuit; each of the sub-transmitting channels is configured to generate an output RF signal at its respective output end based on an input digital signal; and a processing module connected to the first coupling line structure and configured to perform predistortion based on the signal from the first coupling line structure.

[0009] In a second aspect, the present disclosure provides an antenna device, comprising: an antenna circuit, comprising multiple sub-transmitting channels; each of the sub-transmitting channels is used to generate an output radio frequency signal at its respective output end based on an input digital signal; and a DPD circuit, comprising a first coupling line structure and a processing module; the first coupling line structure couples the output ends of the multiple sub-transmitting channels; the processing module is connected to the first coupling line structure and is used to perform predistortion based on the signal from the first coupling line structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In the drawings accompanying this disclosure:

[0011] FIG1 is a block diagram of an antenna device in the related art;

[0012] FIG2 is a block diagram of an antenna circuit of an antenna device in the related art;

[0013] FIG3 is a block diagram of a wave control chip of an antenna device in the related art;

[0014] FIG4 is a block diagram of a DPD circuit provided by the present disclosure;

[0015] FIG5 is a block diagram of the antenna device provided by the present disclosure;

[0016] FIG6 is a block diagram of the antenna device provided by the present disclosure;

[0017] FIG7 is a block diagram of the antenna device provided by the present disclosure;

[0018] FIG8 is a flow chart of a DPD process and an antenna calibration process in an antenna device provided by the present disclosure;

[0019] FIG9 is a schematic diagram of a process for calculating a DPD coefficient in an antenna device provided by the present disclosure;

[0020] FIG10 is a schematic diagram of a process for calculating a DPD coefficient in an antenna device provided by the present disclosure;

[0021] FIG11 is a schematic diagram of a process for calculating a DPD coefficient in the antenna device provided by the present disclosure.

[0022] In the present disclosure, the meanings of the figure marks include: 1. DPD circuit; 11. First coupling line structure; 111. First coupling line; 112. First combined line; 12. Second coupling line structure; 121. Second coupling line; 122. Second combined line; 13. Processing module; 19. Switch module; 2. Antenna circuit; 21. RF channel; 211. Sub-transmitting channel; 212. Sub-receiving channel; 3. Antenna array; 31. Transceiver antenna; 8. Antenna device; 9. Detection antenna. DETAILED DESCRIPTION

[0023] To enable those skilled in the art to better understand the technical solution of the present disclosure, the DPD circuit and antenna device provided by the present disclosure are described in detail below with reference to the accompanying drawings.

[0024] The present disclosure will be described more fully below with reference to the accompanying drawings, but the embodiments shown may be embodied in different forms, and the present disclosure should not be construed as limited to the embodiments set forth below. These embodiments are provided to make the present disclosure more thorough and complete and to enable those skilled in the art to fully understand the scope of the present disclosure.

[0025] The accompanying drawings of the present disclosure are used to provide a further understanding of the embodiments of the present disclosure and constitute a part of the specification. Together with the detailed embodiments, they are used to explain the present disclosure and do not constitute a limitation of the present disclosure. By describing the detailed embodiments with reference to the accompanying drawings, the above and other features and advantages will become more apparent to those skilled in the art.

[0026] The present disclosure may be described with reference to plan views and / or cross-sectional views by way of ideal schematic views of the present disclosure. Therefore, the exemplary illustrations may be modified according to manufacturing techniques and / or tolerances.

[0027] In the absence of conflict, the various embodiments of the present disclosure and the various features therein may be combined with each other.

[0028] The terms used in this disclosure are only used to describe specific embodiments and do not limit this disclosure. As used in this disclosure, the term "and / or" includes any and all combinations of one or more related enumerated items. As used in this disclosure, the singular forms "a" and "the" also include plural forms, unless the context clearly indicates otherwise. As used in this disclosure, the terms "comprising" and "made of" specify the presence of specific features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or groups thereof.

[0029] Unless otherwise defined, all terms (including technical and scientific terms) used in this disclosure have the same meanings as those commonly understood by those skilled in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and this disclosure, and will not be interpreted as having an idealized or overly formal meaning unless expressly defined in this disclosure.

[0030] The present disclosure is not limited to the embodiments shown in the drawings, but includes modifications of the configurations formed based on the manufacturing process. Therefore, the regions illustrated in the drawings have schematic properties, and the shapes of the regions shown in the drawings illustrate the specific shapes of the regions of the elements, but are not restrictive.

[0031] In a wireless communication system such as an active antenna unit (AAU) of a base station, the antenna device 8 for transmitting and receiving wireless signals is one of the important components.

[0032] 1 , an antenna device 8 (such as an antenna device with a millimeter-wave hybrid beamforming architecture) may include an antenna circuit 2 and an antenna array 3 .

[0033] The antenna array 3 includes an array of multiple transceiver antennas 31, such as an array of 5G (fifth-generation mobile communication technology) millimeter-wave active phased array antennas. The radio frequency signal (output radio frequency signal) generated by the antenna circuit 2 can be transmitted to the corresponding transceiver antenna 31 and transmitted through the air interface (OTA, Over The Air) in the form of an electromagnetic wave wireless signal to achieve signal transmission; and the transceiver antenna 31 can also receive wireless signals and convert the received wireless signals into radio frequency signals (input radio frequency signals), and then send them to the antenna circuit 2 for processing to achieve signal reception.

[0034] The antenna circuit 2 includes multiple sub-transmitting channels 211, each of which can convert the digital signal (input digital signal) input from other structures (such as the baseband processing unit) into a radio frequency signal (output radio frequency signal) and output it to the antenna array 3 at its respective output end (the right end of Figure 1).

[0035] In order to generate an output RF signal with sufficient power, the sub-transmitting channel 211 usually includes devices such as a power amplifier (PA). Since devices such as PA cannot be ideal devices but have a certain gain curve (such as a PA gain curve), the signal passing through the sub-transmitting channel 211 will undergo nonlinear changes (nonlinear distortion), which in turn affects the linear indicators of the antenna device 8, resulting in increased back-off and reduced efficiency (such as PA efficiency).

[0036] To this end, digital pre-distortion (DPD) can be used to reduce or eliminate the impact of the above nonlinear distortion, that is, to obtain the actual signal output by the sub-transmitting channel 211, and compare the difference between the actual signal and the standard signal (the signal that "theoretically should be generated" according to the input digital signal), and adjust the input digital signal (such as the baseband signal) in reverse according to the difference, and transform the input digital signal into a form complementary to the gain curve of the PA, so that the wireless signal generated according to the adjusted input digital signal has good linearity, which can improve the linearity index of the antenna device 8, reduce back-off, and improve efficiency.

[0037] In some related technologies, referring to Figure 1, in order to obtain the actual signal output by the sub-transmitting channel 211, an "offline DPD" method can be adopted. That is, when the antenna device 8 sends a wireless signal, an additional detection antenna 9 (passive antenna) is used to obtain the wireless signal sent by the transceiver antenna 31, and pre-distortion is performed based on the comparison between the wireless signal and the input digital signal.

[0038] However, the antenna device 8 in actual use cannot be equipped with the above detection antenna, so the above method can only be used in the debugging of the antenna device 8 before leaving the factory, and the measured nonlinear information is archived according to temperature, frequency, etc., and offline DPD is performed; but the above method cannot be used for the antenna device 8 in actual use, that is, it cannot be performed "online", so the above method cannot be adjusted according to the actual use situation, and a good DPD effect cannot be obtained.

[0039] In some related technologies, the "online DPD" method can also be used to eliminate the above nonlinearity, that is, a coupler and other devices are respectively set after each sub-transmitting channel 211 to respectively collect the output RF signal of each sub-transmitting channel 211 for comparison with the input digital signal and pre-distortion.

[0040] However, according to the above method, multiple devices such as couplers must be set after each sub-transmitting channel 211. Due to the large number of sub-transmitting channels 211, a large number of devices and structures must be added to the antenna device 8 to implement DPD, which makes the structure complex and the cost high.

[0041] It should be understood that, referring to Figure 2, the antenna circuit 2 may also include multiple sub-receiving channels 212, which are used to convert the input RF signal received and converted by the antenna array 3 into a digital signal (output digital signal) and output it at the output end of the sub-receiving channel 212 (the left end of Figure 2) to other structures (such as a baseband processing unit) for processing.

[0042] It should be understood that, in order to simplify the structure, some structures in the sub-transmitting channel 211 and the sub-receiving channel 212 can be "shared".

[0043] For example, referring to Figure 2, in an antenna device 8 with a millimeter-wave hybrid beamforming architecture, the antenna circuit 2 may include multiple (e.g., N) RF channels (or RF links) 21, each RF channel 21 includes multiple sub-transmit channels 211 and multiple sub-receive channels 212, and the sub-transmit channels 211 correspond to the sub-receive channels 212 one-to-one, and some structures in the corresponding sub-transmit channels 211 and sub-receive channels 212 are "shared".

[0044] For example, referring to Figure 2, each RF channel 21 may be provided with a digital-to-analog converter (DAC) corresponding to the sub-transmitting channel 211, and an analog-to-digital converter (ADC) corresponding to the sub-receiving channel 212. The two are respectively connected to the millimeter wave switch through an up-converter (the up-converter is also connected to the local oscillator) and a down-converter (the down-converter is also connected to the local oscillator). The millimeter wave switch is then connected to multiple (such as M) beam control chips (beam control chips) through a power divider. Each beam control chip corresponds to multiple (such as k) sub-transmitting channels 211 and multiple sub-receiving channels 212.

[0045] For example, referring to Figure 3, each wave control chip may correspond to four (assuming k = 4) sub-transmitting channels 211 and four (sub-receiving channels 212; in the wave control chip, each sub-transmitting channel 211 includes a wave control part, which includes a first amplitude modulation module, a first phase modulation module, and a PA arranged in sequence (from left to right in Figure 3); and each sub-receiving channel 212 also has a wave control part in the wave control chip, which includes a second amplitude modulation module, a second phase modulation module, and a low noise amplifier (LNA) arranged in sequence (from left to right in Figure 3).

[0046] In the wave control chip, one end (the left end in FIG3 ) of the two wave control parts of the corresponding sub-transmitting channel 211 and the sub-receiving channel 212 is connected to a first wave control switch, and the other end (the right end in FIG3 ) is connected to a second wave control switch.

[0047] Each first wave-controlled switch is connected to the same port of the wave-controlled chip, which is connected to the above power divider; and each second wave-controlled switch is connected to different ports of the wave-controlled chip, each port is the output end of a sub-transmitting channel 211 and the input end of a sub-receiving channel 212, that is, these ports are connected to the antenna array 3.

[0048] It can be seen that each wave control chip corresponds to k sub-transmitting channels 211 and k sub-receiving channels 212, each RF channel 21 includes M*k sub-transmitting channels 211 and M*k sub-receiving channels 212, and each antenna device 8 includes N*M*k sub-transmitting channels 211 and N*M*k sub-receiving channels 212; the sub-transmitting channels 211 and the sub-receiving channels 212 correspond one to one, and the corresponding sub-transmitting channels 211 and the sub-receiving channels 212 have some shared structures, so the state of each switch (millimeter wave switch, first wave control switch, second wave control switch) can be used to control the transmission or reception of each channel accordingly.

[0049] It should be understood that in the present disclosure, the specific structures of the RF channel 21, the wave control chip, the sub-transmitting channel 211, and the sub-receiving channel 212 are not limited to the above examples. As long as the antenna circuit 2 includes multiple relatively independent sub-transmitting channels 211 that can convert the input digital signal into the output RF signal, it is feasible.

[0050] In a first aspect, referring to FIG. 4 to FIG. 11 , the present disclosure provides a DPD circuit 1 .

[0051] The DPD circuit 1 proposed in the present disclosure is used to perform digital pre-distortion (DPD) on an antenna circuit 2 , in particular, to perform “online DPD”.

[0052] 4 , the DPD circuit 1 provided by the present disclosure includes: a first coupled line structure 11 and a processing module 13 .

[0053] The first coupling line structure 11 is used to couple the output ends of multiple sub-transmitting channels 211 of the antenna circuit 2; each sub-transmitting channel 211 is used to generate an output radio frequency signal at its own output end according to an input digital signal.

[0054] The processing module 13 is connected to the first coupled line structure 11 and is configured to perform predistortion according to the signal from the first coupled line structure 11 .

[0055] 4 , the DPD circuit 1 provided in the present disclosure includes a first coupled line structure 11, which couples the output ends of all sub-transmitting channels 211 and connects to a processing module 13. Therefore, the first coupled line structure 11 can obtain the output RF signals of all sub-transmitting channels 211 and input the obtained output RF signals into the processing module 13 for pre-distortion processing.

[0056] In the DPD circuit 1 provided by the present disclosure, the first coupled-line structure 11 can collect the output RF signals of all sub-transmitting channels 211 and provide them to the processing module 13 for pre-distortion. Therefore, it does not require the use of additional devices such as a "detection antenna", and can achieve "online DPD" with good DPD effect. At the same time, the first coupled-line structure 11 is only a lead rather than a device such as a coupler. That is, the DPD circuit 1 provided by the present disclosure can achieve DPD by setting up a few simple leads without adding complex structures such as couplers. Therefore, it is low-cost and easy to use.

[0057] In some embodiments, referring to FIG. 6 , the DPD circuit 1 provided by the present disclosure further includes: a second coupling line structure 12 and a switch module 19 .

[0058] The second coupling line structure 12 is used to couple the output ends of the plurality of sub-transmitting channels 211 .

[0059] The switch module 19 , through which the first coupling line structure 11 and the second coupling line structure 12 are respectively connected to the processing module 13 , is used to connect the first coupling line structure 11 or the second coupling line structure 12 to the processing module 13 .

[0060] The processing module 13 is further configured to perform antenna calibration according to the signal from the second coupling-line structure 12 .

[0061] As an embodiment of the present disclosure, the DPD circuit 1 may further be provided with a second coupling-line structure 12, which is also coupled to the output ends of multiple (not necessarily all) sub-transmitting channels 211, and the second coupling-line structure 12 and the first coupling-line structure 11 are respectively connected to two different input ends of the switch module 19, and the output end of the switch module 19 is further connected to the processing module 13, so that the switch module 19 can selectively connect the first coupling-line structure 11 or the second coupling-line structure 12 to the processing module 13, that is, select the signal of the first coupling-line structure 11 or the second coupling-line structure 12 to be input to the processing module 13, so that the processing module 13 can perform pre-distortion based on the signal from the first coupling-line structure 11, or perform antenna correction (AC) based on the signal from the second coupling-line structure 12.

[0062] In a second aspect, referring to FIG. 4 to FIG. 11 , the present disclosure provides an antenna device 8 .

[0063] The antenna device 8 provided by the present disclosure has the above DPD circuit 1 , so that the antenna device 8 itself has a DPD function, especially an “online DPD” function.

[0064] 5 , the antenna device 8 provided by the present disclosure includes: an antenna circuit 2 and a DPD circuit 1 .

[0065] The antenna circuit 2 includes a plurality of sub-transmitting channels 211 ; each sub-transmitting channel 211 is used to generate an output radio frequency signal at its own output end according to an input digital signal.

[0066] The DPD circuit 1 includes a first coupled-line structure 11 and a processing module 13; the first coupled-line structure 11 couples the output ends of multiple sub-transmitting channels 211; the processing module 13 is connected to the first coupled-line structure 11 and is used to perform predistortion based on the signal from the first coupled-line structure 11.

[0067] It should be understood that, with reference to FIG. 6 , the antenna device 8 provided in the present disclosure may further include other structures such as an antenna array 3 .

[0068] For example, the antenna array 3 may include multiple transceiver antennas 31 arranged in an array, which are used to convert the output RF signal generated by the antenna circuit 2 into a wireless signal in the form of electromagnetic waves and send it out, as well as receive wireless signals and convert them into input RF signals for processing by the antenna circuit 2, etc., which will not be described in detail here.

[0069] In the antenna device 8 provided by the present disclosure, the first coupling line structure 11 can collect the output RF signals of all sub-transmitting channels 211 and provide them to the processing module 13 for pre-distortion. Therefore, it does not require the use of additional devices such as a "detection antenna" and can achieve "online DPD" with good DPD effect. At the same time, the first coupling line structure 11 is only a lead rather than a device such as a coupler. That is, the antenna device 8 provided by the present disclosure can achieve DPD by setting some simple leads without adding complex structures such as couplers, so it is low-cost and easy to use.

[0070] In some embodiments, the antenna circuit 2 includes multiple RF channels 21, each RF channel 21 includes multiple sub-transmitting channels 211; the first coupling line structure 11 includes a first combining line 112, and multiple first coupling lines 111 corresponding one to one to the RF channels 21; each first coupling line 111 couples all the sub-transmitting channels 211 of the corresponding RF channel 21 in series; the first combining line 112 combines all the first coupling lines 111 and connects to the processing module 13.

[0071] As some embodiments of the present disclosure, referring to Figure 7, each RF channel 21 (or RF link) includes multiple (e.g., M) wave control chips, and each wave control chip corresponds to multiple (e.g., K) sub-transmitting channels 211, so each RF channel 21 includes multiple (e.g., k*M) sub-transmitting channels 211.

[0072] It should be understood that the antenna device 8 provided in the present disclosure may also include multiple sub-receiving channels 212. For example, referring to Figures 2 and 3, the sub-receiving channels 212 and the sub-transmitting channels 211 are one-to-one corresponding, and some structures of the sub-receiving channels 212 and the sub-transmitting channels 211 are "shared".

[0073] It should be understood that the specific structures of the RF channel 21, wave control chip, sub-receiving channel 212, sub-transmitting channel 211, etc. in the present disclosure are diverse. For example, they can adopt the form of reference Figures 2 and 3, or the form of other related technologies, and will not be described in detail here.

[0074] As some embodiments of the present disclosure, referring to Figure 7, when the antenna circuit 2 includes multiple RF channels 21, and each RF channel 21 includes multiple sub-transmitting channels 211, the output ends of all sub-transmitting channels 211 in each RF channel 21 can be coupled in series through a first coupling line 111, so that the first coupling line 111 corresponds to the RF channel 21 one by one, and multiple (such as N) first coupling lines 111 are then combined and connected by a first combiner line 112, and the first combiner line 112 is further connected to the processing module 13.

[0075] It can be seen that the sub-transmitting channels 211 in each RF channel 21 are usually closer and easier to connect, so the sub-transmitting channels 211 in each RF channel 21 can be connected in series first, and then the connections between different RF channels 21 can be combined.

[0076] In some embodiments, the first coupling line 111 is a microstrip line.

[0077] As an embodiment of the present disclosure, the first coupling line 111 used to achieve series coupling can be in the form of a "microstrip line", that is, a transmission line composed of a single conductor strip on a dielectric substrate. Since the first coupling line 111 is located inside the RF channel 21, the first coupling line 111 is more suitable for implementation in the form of a microstrip line.

[0078] It should be understood that other leads in the present disclosure, such as the first combined line 112, the second coupled line 121, the second combined line 122, etc., may also be in the form of microstrip lines; or, the leads in the present disclosure may also be in other forms, which will not be described in detail here.

[0079] In some implementations, the DPD circuit 1 further includes: a second coupling line structure 12 and a switch module 19 .

[0080] The second coupling line structure 12 couples the output ends of the plurality of sub-transmitting channels 211 .

[0081] The switch module 19 , through which the first coupling line structure 11 and the second coupling line structure 12 are respectively connected to the processing module 13 , is used to connect the first coupling line structure 11 or the second coupling line structure 12 to the processing module 13 .

[0082] The processing module 13 is further configured to perform antenna calibration according to the signal from the second coupling-line structure 12 .

[0083] As an embodiment of the present disclosure, the performance of the devices (such as DAC, up-converter, etc.) in the RF channel 21 of the antenna circuit 2 will affect the amplitude and phase of the signal in the RF channel 21. Since the devices in different RF channels 21 are inconsistent, the amplitude and phase of the signals in different RF channels 21 will be different. If the difference is too large, the consistency of the performance of each RF channel 21 will be reduced.

[0084] To this end, the antenna circuit 2 can also perform “antenna calibration (AC)”, that is, according to the difference in signals in different RF channels 21 , different adjustments are made to each RF channel 21 (such as different adjustments are made to the input digital signal).

[0085] 6 , the DPD circuit 1 may further include a second coupled-line structure 12 , which is also coupled to the output ends of multiple (not necessarily all) sub-transmitting channels 211 , and the second coupled-line structure 12 and the first coupled-line structure 11 are respectively connected to two different input ends of the switch module 19 , while the output end of the switch module 19 is further connected to the processing module 13 .

[0086] Thus, the switch module 19 can selectively connect the first coupling-line structure 11 or the second coupling-line structure 12 to the processing module 13. That is, the switch module 19 can selectively input the signal of the first coupling-line structure 11 or the second coupling-line structure 12 to the processing module 13, so that the processing module 13 can perform predistortion based on the signal from the first coupling-line structure 11 or perform antenna calibration (AC) based on the signal from the second coupling-line structure 12.

[0087] Since different signals are required for predistortion and antenna calibration, the switch module 19 does not "simultaneously" connect the first coupling line structure 11 and the second coupling line structure 12 to the processing module 13. Instead, at most, it connects only one of the two to the processing module 13.

[0088] It should be understood that when neither pre-distortion nor antenna correction is required, the switch module 19 can be completely turned off, that is, the first coupling line structure 11 and the second coupling line structure 12 are disconnected from the processing module 13, thereby ensuring that no signal enters the processing module 13.

[0089] Therefore, the antenna device 8 provided by the present invention can also realize the "antenna correction" function. Moreover, the antenna correction and DPD are processed by the same processing module 13, so there is no need to set up an additional processor, etc., but only a simple lead (second coupling line structure 12) and a switch (switch module 19) need to be added. Therefore, the antenna device 8 has a simple structure and low cost.

[0090] It should be understood that the specific form of the processing module 13 in the antenna device 8 provided in the present disclosure is diverse, as long as it can implement the function of DPD (or antenna correction).

[0091] For example, referring to Figure 7, the processing module 13 may include a downconverter for downconverting the signal from the first coupling line structure 11 (or the second coupling line structure 12) according to the local oscillator; and the output end of the downconverter is connected to an analog-to-digital converter (ADC) for converting the downconverted signal into a digital signal; the output end of the ADC is connected to the processing unit, and the processing unit performs corresponding calculations based on the digital signal converted by the ADC and the input digital signal to determine how to compensate the antenna circuit 2, that is, to achieve DPD (or antenna correction).

[0092] The processing unit can be another separate device outside the antenna circuit 2, so that the processing unit can input the generated processing results into the antenna circuit 2 to control the operation of the antenna circuit 2; alternatively, the processing unit can also be a device with data processing capabilities already in the antenna circuit 2, such as a baseband processing unit (BBU, Base Band Unite).

[0093] It should be understood that the specific algorithms for antenna calibration in the present disclosure are diverse, and methods in related arts may be adopted.

[0094] For example, when performing antenna calibration (AC), the sub-transmitting channels 211 corresponding to the second coupling line structure 12 in multiple RF channels 21 can simultaneously generate output RF signals under a predetermined input digital signal, and the switch module 19 is placed in a state that connects the second coupling line structure 12 and the processing module 13, so that the output RF signal is collected through the second coupling line structure 12 and input into the processing module 13. The processing module 13 determines how to adjust the input digital signal of each RF channel 21 based on the collected signal and the corresponding input digital signal, for example, determining the amplitude and phase calibration coefficient c (or calibration filter coefficient).

[0095] In some embodiments, the antenna circuit 2 includes multiple RF channels 21, each RF channel 21 includes multiple sub-transmitting channels 211; the second coupling line structure 12 includes a second combining line 122, and multiple second coupling lines 121 corresponding one to one with the RF channels 21; each second coupling line 121 is connected to the output end of a sub-transmitting channel 211 in the corresponding RF channel 21, and the second combining line 122 combines all the second coupling lines 121 and is connected to the switch module 19.

[0096] 7 , as one embodiment of the present disclosure, since antenna calibration is mainly used to compensate for differences between different RF channels 21 , for antenna calibration, it is sufficient to collect the output RF signal of only one sub-transmitting channel 211 in each RF channel 21 ; therefore, the second coupling line structure 12 may include a plurality of (N) second coupling lines 121 corresponding one-to-one to the RF channels 21 , each second coupling line 121 being connected to the output end of a selected sub-transmitting channel 211 in the corresponding RF channel 21 , and the second combining line 122 combining the second coupling lines 121 and connecting to the processing module 13 (specifically, through the switch module 19 ).

[0097] In some embodiments, referring to FIG. 8 , performing predistortion according to the signal from the first coupled-line structure 11 includes steps A101 to A103 .

[0098] A101 , controlling the plurality of sub-transmitting channels 211 to generate output RF signals at their respective output terminals one by one in sequence.

[0099] A102 : When each sub-transmitting channel 211 generates an output RF signal at its respective output end, obtain a DPD sampling signal of the sub-transmitting channel 211 through the first coupled line structure 11 .

[0100] A103 : Predistort the input digital signal according to the multiple DPD sampling signals and the input digital signal when each DPD sampling signal is collected.

[0101] As an embodiment of the present disclosure, when pre-distortion is to be performed, each sub-transmitting channel 211 can be controlled to generate an output RF signal in turn under the drive of a specific input digital signal (Pin); and when each sub-transmitting channel 211 generates an output RF signal, the signal is introduced into the processing module 13 through the first coupling line structure 11.

[0102] The signal collected at the output of each sub-transmitting channel 211 can be a phase-amplitude signal (Pfb) including amplitude and phase, that is, the DPD sampling signal of the sub-transmitting channel 211; and when collecting each Pfb, the input digital signal (Pin) input to the sub-transmitting channel 211 is also known.

[0103] Therefore, the processing module 13 can calculate how to compensate the input digital signal based on multiple Pfb (Pfb1, Pfb2...PfbM*N*K) and their corresponding Pins, and pre-distort (or "pre-distortion training") the subsequent input digital signal (such as the baseband signal) to complete the DPD process.

[0104] It should be understood that if the DPD circuit 1 further includes a second coupled line structure 12 and a switch module 19, then when performing predistortion, the switch module 19 should be placed in a state where the first coupled line structure 11 and the processing module 13 are connected, while the connection between the second coupled line structure 12 and the processing module 13 is cut off.

[0105] It should be understood that the above DPD process can be performed when the antenna device 8 enters the actual use state, that is, "online DPD"; but at the moment of online DPD, the antenna device 8 may not be sending or receiving actual working signals, that is, online DPD can be performed in the "working gap" of the antenna device 8 that has been put into use, so as not to affect the normal operation of the antenna device 8.

[0106] In some embodiments, the input digital signal when each DPD sampling signal is collected is the same; referring to FIG8 , pre-distorting the input digital signal (A103) based on the multiple DPD sampling signals and the input digital signal when each DPD sampling signal is collected includes steps A1031 and A1032.

[0107] A1031. Determine a DPD coefficient based on multiple DPD sampling signals and an input digital signal.

[0108] A1032. Predistort the input digital signal according to the DPD coefficient.

[0109] As an embodiment of the present disclosure, during the DPD process, all sub-transmitting channels 211 can generate an output RF signal (i.e., a phase-amplitude signal Pfb) based on the same input digital signal (Pin), so that the corresponding DPD coefficient (Pindpd) can be calculated based on the Pin and multiple Pfb (Pfb1, Pfb2…PfbM*N*K), and the antenna circuit 2 can be pre-distorted (pre-distortion training) subsequently based on the Pindpd.

[0110] There are various specific ways to calculate Pindpd based on the above Pin and multiple Pfbs (Pfb1, Pfb2...PfbM*N*K).

[0111] For example, the processing module 13 may calculate a calibration amplitude and phase signal (Pota') according to each Pfb and a predetermined amplitude and phase calibration coefficient c (or calibration filter coefficient), that is:

[0112] Pota'=c*Pfb;

[0113] c can be a "set" of coefficients for each sub-transmitting channel 211, which can be understood as a matrix of M*N*k dimensions. Accordingly, the multiplication operation of determining Pota' based on Pfb and c is also a matrix operation, which is equivalent to:

[0114] Potal1'=Pfb1*c1;

[0115] Pota2'=Pfb2*c2;

[0116] …

[0117] PotaN*M*k'=(PfbN*M*k)*(cN*M*k).

[0118] Thus, multiple Pota' (Pota1', Pota2'...PotaM*N*K') can be calculated based on multiple Pfb (Pfb1, Pfb2...PfbM*N*K); further, the processing module 13 can compare Pin with multiple Pota' (Pota1', Pota2'...PotaM*N*k') to calculate Pindpd.

[0119] Pindpd can also be a "set" of coefficients, such as a matrix of M*N*k dimensions.

[0120] According to the above Pindpd, the "original" input digital signal (such as the baseband signal) of each sub-transmitting channel 211 can be fitted to obtain an optimized input digital signal, and the output RF signal and wireless signal generated according to the optimized input digital signal have good linearity.

[0121] There are various ways to calculate Pindpd based on Pin and Pota'.

[0122] For example, referring to Figure 9, as an embodiment of the present disclosure, Pota1', Pota2'...PotaM*N*K' can be superimposed to obtain an approximate far-field main beam signal, and the approximate far-field main beam signal can be compared with Pin to extract coefficients to obtain Pindpd.

[0123] Alternatively, referring to Figure 10, as an embodiment of the present disclosure, Pin can be compared with each Pota' (Pota1, Pota2'...PotaM*N*K') separately (coefficient extraction) to obtain the sub-channel DPD coefficient corresponding to each sub-transmitter channel 211, and then the sub-channel DPD coefficients are superimposed, and the sub-channel coefficients are extracted to obtain Pindpd.

[0124] Alternatively, referring to FIG11 , multiple Pota' (Pota1', Pota2'...PotaM*N*K') data may be normalized (e.g., amplitude normalization) and stacked into a matrix form, and Pin may also be matrix-expanded into a matrix form, and then the two matrices may be compared to obtain Pindpd.

[0125] In some embodiments, referring to FIG. 8 , the processing module 13 is further configured to perform initial sub-channel calibration. The initial sub-channel calibration ( A100 ) includes steps A1001 to A1003 .

[0126] A1001. Control multiple sub-transmitting channels 211 to generate output RF signals at their respective output terminals one by one in sequence.

[0127] A1002 : When each sub-transmitting channel 211 generates an output RF signal at its respective output end, obtain a first calibration signal and a second calibration signal of the sub-transmitting channel 211 through the first coupling line structure 11 .

[0128] The first calibration signal is a signal collected at the output end of the sub-transmitting channel 211 , and the second calibration signal is a signal collected at the air interface of the antenna device 8 by the detection antenna 9 and then input into the processing module 13 .

[0129] A1003. Calibrate each sub-transmitting channel 211 according to the first calibration signal, the second calibration signal, and the input digital signal when collecting each first calibration signal.

[0130] As an embodiment of the present disclosure, referring to FIG8 , the processing module 13 can also be used to perform an initial calibration on each sub-transmitting channel 211 before the antenna device 8 leaves the factory, namely, “initial sub-channel calibration”, specifically, to calibrate the amplitude and phase of each sub-transmitting channel 211 .

[0131] During the initial sub-channel calibration, each sub-transmitting channel 211 can be controlled to generate an output RF signal in turn under a specific input digital signal (Pin). The output RF signal is input to the processing module 13 through the first coupling line structure 11 (and also through the switch module 19) as the "first calibration signal", that is, the phase and amplitude signal (Pfb).

[0132] At the same time, when each sub-transmitting channel 211 generates an output RF signal, it will also generate a wireless signal in the form of an electromagnetic wave at the air interface of the antenna device 8 through the antenna array 3. Referring to Figure 7, the wireless signal can be collected at the air interface through the detection antenna (passive antenna) 9, and the wireless signal can be input into the processing module as a second calibration signal (Pota).

[0133] Therefore, by comparing Pin, multiple Pfb (Pfb1, Pfb2...PfbM*N*K), and multiple Pota (Pota1, Pota2...PotaM*N*K), the result for initial sub-channel calibration can be obtained, for example, the above-mentioned amplitude and phase calibration coefficients c can be obtained, specifically a set of coefficients corresponding to each sub-transmitting channel 211 respectively.

[0134] It should be understood that the various structures and algorithms in the present disclosure are not limited to the forms of the above specific examples. They can also adopt methods in other related technologies, which will not be described in detail here.

[0135] The present disclosure has disclosed example embodiments, and although specific terms are employed, they are used and should be interpreted only in a general illustrative sense and not for purposes of limitation. In some instances, it will be apparent to those skilled in the art that, unless otherwise expressly stated, features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements described in conjunction with other embodiments. Therefore, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the scope of the present disclosure as set forth in the appended claims.

Claims

1. A digital pre - distortion (DPD) circuit, comprising: A first coupled - line structure for coupling the output ends of multiple sub - transmission channels of an antenna circuit; each of the sub - transmission channels is configured to generate an output radio - frequency signal at its output end according to an input digital signal; A processing module, connected to the first coupled - line structure and configured to perform pre - distortion according to the signal from the first coupled - line structure.

2. The DPD circuit according to claim 1, further comprising: A second coupled - line structure for coupling the output ends of the multiple sub - transmission channels; A switch module, the first coupled - line structure and the second coupled - line structure are respectively connected to the processing module through the switch module, and the switch module is configured to conduct the first coupled - line structure or the second coupled - line structure with the processing module; The processing module is further configured to perform antenna calibration according to the signal from the second coupled - line structure.

3. An antenna device, comprising: An antenna circuit including multiple sub - transmission channels; each of the sub - transmission channels is configured to generate an output radio - frequency signal at its output end according to an input digital signal; A DPD circuit including a first coupled - line structure and a processing module; The first coupled - line structure couples the output ends of the multiple sub - transmission channels; the processing module is connected to the first coupled - line structure and is configured to perform pre - distortion according to the signal from the first coupled - line structure.

4. The antenna device according to claim 3, wherein, The antenna circuit includes multiple radio - frequency channels, and each radio - frequency channel includes multiple sub - transmission channels; The first coupled - line structure includes a first combining line and multiple first coupled lines corresponding one - to - one to the radio - frequency channels; Each of the first coupled lines serially couples all the sub - transmission channels of the corresponding radio - frequency channel; the first combining line combines all the first coupled lines and is connected to the processing module.

5. The antenna device according to claim 4, wherein, The first coupled line is a microstrip line.

6. The antenna device according to claim 3, wherein, Performing pre - distortion according to the signal from the first coupled - line structure includes: Controlling the multiple sub - transmission channels to sequentially generate the output radio - frequency signal at their respective output ends one by one; When each sub - transmission channel generates the output radio - frequency signal at its output end, obtaining the DPD sampling signal of the sub - transmission channel through the first coupled - line structure; Performing pre - distortion on the input digital signal according to the multiple DPD sampling signals and the input digital signal when collecting each DPD sampling signal.

7. The antenna device according to claim 6, wherein The input digital signal when collecting each DPD sampling signal is the same; performing pre - distortion on the input digital signal according to the multiple DPD sampling signals and the input digital signal when collecting each DPD sampling signal includes: Determining DPD coefficients according to the multiple DPD sampling signals and the input digital signal; Performing pre - distortion on the input digital signal according to the DPD coefficients.

8. The antenna device according to claim 3, wherein, The processing module is further configured to perform initial sub - channel calibration, and the initial sub - channel calibration includes: Control multiple said sub-transmission channels to sequentially generate said output radio frequency signal at their respective output ends one by one; When each said sub-transmission channel generates said output radio frequency signal at its respective output end, obtain the first calibration signal and the second calibration signal of this sub-transmission channel through said first coupling line structure; said first calibration signal is the signal collected at the output end of this sub-transmission channel, and said second calibration signal is the signal obtained after the signal collected at the air interface of said antenna device by the detection antenna is input into said processing module; Calibrate each said sub-transmission channel according to said first calibration signal, said second calibration signal, and said input digital signal when collecting each said first calibration signal.

9. The antenna device according to claim 3, wherein, Said DPD circuit further includes: A second coupling line structure that couples the output ends of multiple said sub-transmission channels; A switch module, said first coupling line structure and said second coupling line structure are respectively connected to said processing module through said switch module, and said switch module is used to conduct said first coupling line structure or said second coupling line structure with said processing module; Said processing module is further used to perform antenna correction according to the signal from said second coupling line structure.

10. The antenna device according to claim 9, wherein, Said antenna circuit includes multiple radio frequency channels, and each said radio frequency channel includes multiple said sub-transmission channels; Said second coupling line structure includes a second combining line and multiple second coupling lines corresponding one by one to said radio frequency channels; Each said second coupling line is connected to the output end of one said sub-transmission channel in the corresponding said radio frequency channel, and said second combining line combines and connects all said second coupling lines and is connected to said switch module.

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