Digital predistortion circuit and antenna device

Abstract

The invention provides a digital pre-distortion circuit, which comprises a first coupling line structure used for coupling output ends of a plurality of sub-transmitting channels of an antenna circuit; each sub-transmitting channel is used for generating an output radio frequency signal at the output end of the sub-transmitting channel according to an input digital signal; and the processing module is connected with the first coupling line structure and is used for performing pre-distortion according to a signal from the first coupling line structure. The invention further provides an antenna device.

Description

Technical Field

[0001] The present disclosure relates to the field of digital pre - distortion (DPD) technology, and particularly to a DPD circuit and an antenna device. Background Art

[0002] The performance of an antenna device can be improved through digital pre - distortion (DPD, Digital Pre Distortion).

[0003] However, in the related DPD technology, it either cannot be carried out "online" with poor DPD effect, or a large number of devices (such as multiple couplers) need to be added to the antenna device, resulting in a complex structure and high cost. Summary of the Invention

[0004] The present disclosure provides a DPD circuit and an antenna device.

[0005] In a first aspect, an embodiment of the present disclosure provides a DPD circuit, which includes:

[0006] A first coupling line structure for coupling the output ends of multiple sub - transmission channels of an antenna circuit; each of the sub - transmission channels is used to generate an output radio frequency signal at its output end according to an input digital signal;

[0007] A processing module connected to the first coupling line structure and used to perform pre - distortion according to the signal from the first coupling line structure.

[0008] In a second aspect, an embodiment of the present disclosure provides an antenna device, which includes:

[0009] An antenna circuit including multiple sub - transmission channels; each of the sub - transmission channels is used to generate an output radio frequency signal at its output end according to an input digital signal;

[0010] A DPD circuit including a first coupling line structure and a processing module; the first coupling line structure couples the output ends of the multiple sub - transmission channels; the processing module is connected to the first coupling line structure and used to perform pre - distortion according to the signal from the first coupling line structure.

[0011] In the embodiments of the present disclosure, the first coupling line structure can collect the output radio frequency signals of all sub - transmission channels and provide them to the processing module for pre - distortion. Therefore, it does not need to use additional devices such as "detection antennas" and can achieve "online DPD" with good DPD effect; at the same time, the first coupling line structure is just a lead wire rather than a device such as a coupler. That is, in the embodiments of the present disclosure, DPD can be realized only by setting some simple lead wires without adding complex structures such as couplers. Therefore, it has low cost and is easy to be practical. Description of the Drawings

[0012] In the accompanying drawings of the embodiments of the present disclosure:

[0013] Figure 1 is a block diagram of the composition of an antenna device in the related art;

[0014] Figure 2 is a block diagram of the composition of the antenna circuit of another antenna device in the related art;

[0015] Figure 3 is a block diagram of the composition of the wave control chip of another antenna device in the related art;

[0016] Figure 4 is a block diagram of the composition of a DPD circuit provided by an embodiment of the present disclosure;

[0017] Figure 5 is a block diagram of the composition of an antenna device provided by an embodiment of the present disclosure;

[0018] Figure 6 is a block diagram of the composition of another antenna device provided by an embodiment of the present disclosure;

[0019] Figure 7 is a block diagram of the composition of another antenna device provided by an embodiment of the present disclosure;

[0020] Figure 8 is a schematic flowchart of the DPD process and the antenna calibration process in another antenna device provided by an embodiment of the present disclosure;

[0021] Figure 9 is a schematic diagram of the process of calculating the DPD coefficients in another antenna device provided by an embodiment of the present disclosure;

[0022] Figure 10 is another schematic diagram of the process of calculating the DPD coefficients in another antenna device provided by an embodiment of the present disclosure;

[0023] Figure 11 is another schematic diagram of the process of calculating the DPD coefficients in another antenna device provided by an embodiment of the present disclosure.

[0024] In the embodiments of the present disclosure, the meanings of the reference numerals include:

[0025] 1. DPD circuit; 11. First coupling line structure; 111. First coupling line; 112. First combining line; 12. Second coupling line structure; 121. Second coupling line; 122. Second combining line; 13. Processing module; 19. Switching module; 2. Antenna circuit; 21. RF channel; 211. Sub-transmission channel; 212. Sub-reception channel; 3. Antenna array; 31. Transceiving antenna; 8. Antenna device; 9. Detection antenna. Detailed implementation manners

[0026] To enable those skilled in the art to better understand the technical solutions of the present disclosure, the DPD circuit and the antenna device provided in the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0027] The present disclosure will be described more fully hereinafter with reference to the accompanying drawings. However, the illustrated embodiments may be embodied in different forms and the present disclosure should not be construed as limited to the embodiments set forth below. On the contrary, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0028] The accompanying drawings of the embodiments 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, and are used to explain the present disclosure together with the detailed embodiments, and do not constitute a limitation to 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.

[0029] The present disclosure may be described with reference to the plan view and / or cross-sectional view by means of the ideal schematic diagrams of the present disclosure. Therefore, the example illustrations can be modified according to the manufacturing technology and / or tolerances.

[0030] In the case of no conflict, the embodiments of the present disclosure and the features in the embodiments may be combined with each other.

[0031] The terms used in the present disclosure are only for describing specific embodiments and are not intended to limit the present disclosure. As used in the present disclosure, the term "and / or" includes any and all combinations of one or more of the related listed items. As used in the present disclosure, the singular forms "a" and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. As used in the present disclosure, the terms "comprising", "made of", specify the presence of the stated features, wholes, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their groups.

[0032] Unless otherwise defined, all terms (including technical and scientific terms) used in the present disclosure have the same meaning as commonly understood by those of ordinary skill in the art. It will also be understood that terms such as those defined in common dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted as having an idealized or overly formal meaning unless the present disclosure clearly so defines.

[0033] The present disclosure is not limited to the embodiments shown in the accompanying drawings, but includes modifications to the configurations formed based on the manufacturing process. Therefore, the regions illustrated in the accompanying 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 intended to be restrictive.

[0034] In wireless communication systems such as the active antenna unit (AAU) of a base station, the antenna device 8 for transmitting and receiving wireless signals is one of the important components.

[0035] Referring to Figure 1 , the 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.

[0036] Among them, the antenna array 3 includes an array formed by a plurality of 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 as a wireless signal in the form of an electromagnetic wave through the air interface (OTA, Over The Air) to achieve signal transmission; while the transceiver antenna 31 can also receive the wireless signal and convert it into the form of a radio frequency signal (input radio frequency signal), and then send it to the antenna circuit 2 for processing to achieve signal reception.

[0037] Among them, the antenna circuit 2 includes a plurality of sub-transmission channels 211. Each sub-transmission channel 211 can convert the digital signal (input digital signal) input by other structures (such as a baseband processing unit) into a radio frequency signal (output radio frequency signal), and output it to the antenna array 3 at its output end ( Figure 1 the right end).

[0038] To generate an output radio frequency signal with sufficient power, devices such as power amplifiers (PA, Power Amplifier) are usually included in the sub-transmission channel 211. Since the PA and the like cannot be ideal devices but have a certain gain curve (such as the PA gain curve), the signal passing through the sub-transmission channel 211 will undergo non-linear changes (non-linear distortion), which will affect the linear index of the antenna device 8, resulting in an increase in back-off and a decrease in efficiency (such as PA efficiency).

[0039] Therefore, the influence of the above non-linear distortion can be reduced or eliminated by digital pre-distortion (DPD, Digital Pre Distortion), that is, obtaining the actual signal output by the sub-transmission channel 211, comparing its difference with the standard signal (the signal that "should theoretically be generated" according to the input digital signal), and reversely adjusting the input digital signal (such as the baseband signal) according to the difference, transforming 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, can improve the linear index of the antenna device 8, reduce back-off, and improve efficiency.

[0040] In some related technologies, referring to Figure 1, to obtain the actual signal output by the sub-transmission channel 211, the "offline DPD" method can be adopted, that is, when the antenna device 8 transmits a wireless signal, an additional detection antenna 9 (passive antenna) is used to obtain the wireless signal transmitted by the transceiver antenna 31, and pre-distortion is performed based on the comparison between the wireless signal and the input digital signal.

[0041] However, the above detection antenna cannot be configured for the antenna device 8 in actual use. Therefore, the above method can only be used in the debugging before the antenna device 8 leaves the factory, and the measured non-linear information is archived according to temperature, frequency points, etc. for offline DPD; but the above method cannot be used for the antenna device 8 in actual use, that is, it cannot be "online", so it cannot be adjusted according to the actual use situation and cannot obtain good DPD effects.

[0042] In some other related technologies, the "online DPD" method can also be adopted to eliminate the above non-linearity, that is, couplers and other devices are respectively set after each sub-transmission channel 211 to respectively collect the output radio frequency signals of each sub-transmission channel 211 for comparison with the input digital signal and perform pre-distortion.

[0043] However, according to the above method, a coupler and other multiple devices need to be set after each sub-transmission channel 211. Since the number of sub-transmission channels 211 is large, a large amount of structure needs to be added to the antenna device 8 to achieve DPD, and its structure is complex and the cost is high.

[0044] It should be understood that with reference to Figure 2 , the antenna circuit 2 may further include a plurality of sub-reception channels 212, which are used to convert the input radio frequency signal received and converted by the antenna array 3 into a digital signal (output digital signal) and output it to other structures (such as the baseband processing unit) for processing at its output end ( Figure 2 the left end).

[0045] It should be understood that to simplify the structure, some structures in the sub-transmission channel 211 and the sub-reception channel 212 can be "shared".

[0046] For example, with reference to Figure 2 , in an antenna device 8 with a millimeter-wave hybrid beamforming architecture, the antenna circuit 2 may include a plurality of (such as N) radio frequency channels (or radio frequency links) 21, each radio frequency channel 21 includes a plurality of sub-transmission channels 211 and a plurality of sub-reception channels 212, and the sub-transmission channels 211 and the sub-reception channels 212 correspond one by one, and some structures in the corresponding sub-transmission channels 211 and sub-reception channels 212 are "shared".

[0047] For example, with reference to Figure 2, a digital-to-analog converter (DAC) corresponding to the sub-transmission channel 211 and an analog-to-digital converter (ADC) corresponding to the sub-reception channel 212 can be provided in each radio frequency channel 21. The two are respectively connected to the millimeter-wave switch through an up-converter (which is also connected to the local oscillator) and a down-converter (which is also connected to the local oscillator). The millimeter-wave switch is then connected to multiple (such as M) beam control chips (wave control chips) through a power divider. Each wave control chip corresponds to multiple (such as k) sub-transmission channels 211 and multiple sub-reception channels 212.

[0048] For example, referring to Figure 3 , each wave control chip can correspond to 4 (assuming k = 4) sub-transmission channels 211 and 4 sub-reception channels 212; within the wave control chip, each sub-transmission channel 211 includes a wave control part, and this wave control part includes a first amplitude modulation module, a first phase modulation module, and a PA arranged in sequence (in the Figure 3 from left to right direction); and each sub-reception channel 212 also has a wave control part within the wave control chip, and this wave control part includes a second amplitude modulation module, a second phase modulation module, and a low-noise amplifier (LNA, Low Noise Amplifier) arranged in sequence (in the Figure 3 from left to right direction).

[0049] Within the wave control chip, one end (the Figure 3 left end in Figure 3 ) of the wave control parts of the corresponding sub-transmission channel 211 and sub-reception channel 212 is connected to a first wave control switch, and the other end (the Figure 3 right end in

[0050] ) is connected to a second wave control switch.

[0050] Among them, each first wave control switch is connected to the same port of the wave control chip, and this port is connected to the above-mentioned power divider; and each second wave control switch is respectively connected to different ports of the wave control chip. Each port is the output end of a sub-transmission channel and the input end of a sub-reception channel 212, that is, these ports are connected to the antenna array 3.

[0051] It can be seen from this that each wave control chip corresponds to k sub-transmission channels 211 and k sub-reception channels 212, each radio frequency channel 21 includes M * k sub-transmission channels 211 and M * k sub-reception channels 212, and each antenna device 8 includes N * M * k sub-transmission channels 211 and N * M * k sub-reception channels 212; among them, the sub-transmission channels 211 and sub-reception channels 212 correspond one by one, and some structures are shared between the corresponding sub-transmission channels 211 and sub-reception channels 212. Therefore, through the states of each switch (millimeter-wave switch, first wave control switch, second wave control switch), the signals of each channel can be correspondingly controlled to be transmitted or received.

[0052] It should be understood that in the embodiments of the present disclosure, the specific structures of the radio frequency channel 21, the wave control chip, the sub-transmission channels 211, and the sub-reception channels 212 are not limited to the above examples. As long as the antenna circuit 2 includes a plurality of relatively independent sub-transmission channels 211 that can convert the input digital signal into an output radio frequency signal, it is feasible.

[0053] In a first aspect, referring to Figures 4 to 11 , an embodiment of the present disclosure provides a DPD circuit 1.

[0054] The DPD circuit 1 implemented in the present disclosure is used for digital pre-distortion (DPD, Digital PreDistortion) of the antenna circuit 2, especially for "online DPD".

[0055] Referring to Figure 4 , the DPD circuit 1 of the embodiment of the present disclosure includes:

[0056] A first coupling line structure 11, which is used to couple the output ends of a plurality of sub-transmission channels 211 of the antenna circuit 2; each sub-transmission channel 211 is used to generate an output radio frequency signal at its output end according to the input digital signal;

[0057] A processing module 13, which is connected to the first coupling line structure 11 and is used to perform pre-distortion according to the signal from the first coupling line structure 11.

[0058] Referring to Figure 4 , the DPD circuit 1 of the embodiment of the present disclosure includes a first coupling line structure 11, which couples the output ends of all sub-transmission channels 211 and is connected to the processing module 13; therefore, the first coupling line structure 11 can obtain the output radio frequency signals of all sub-transmission channels 211 and input them into the processing module 13 for pre-distortion processing.

[0059] In the embodiments of the present disclosure, the first coupling line structure 11 can collect the output radio frequency signals of all sub-transmission channels 211 and provide them to the processing module 13 for pre-distortion. Therefore, it does not need to use additional devices such as "detection antennas" and can implement "online DPD" with good DPD effects; at the same time, the first coupling line structure 11 is just a lead wire rather than a coupler or other devices, that is, in the embodiments of the present disclosure, only some simple lead wires need to be set to implement DPD without adding complex structures such as couplers, so its cost is low and it is easy to use.

[0060] In some embodiments, referring to Figure 6 , the DPD circuit 1 of the embodiment of the present disclosure further includes:

[0061] A second coupling line structure 12, which is used to couple the output ends of a plurality of sub-transmission channels 211;

[0062] The switch module 19, the first coupled-line structure 11, and the second coupled-line structure 12 are respectively connected to the processing module 13 through the switch module 19. The switch module 19 is used to conduct the first coupled-line structure 11 or the second coupled-line structure 12 to the processing module 13.

[0063] The processing module 13 is further used to perform antenna calibration according to the signal from the second coupled-line structure 12.

[0064] As a way of the embodiment of the present disclosure, a second coupled-line structure 12 may also be provided in the DPD circuit 1. The second coupled-line structure 12 is also coupled to the output ends of multiple (not necessarily all) sub-transmission channels 211. 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, and the output end of the switch module 19 is connected to the processing module 13. Thus, the switch module 19 can selectively conduct the first coupled-line structure 11 or the second coupled-line structure 12 to the processing module 13, that is, selectively input the signal of the first coupled-line structure 11 or the second coupled-line structure 12 to the processing module 13, so that the processing module 13 can perform pre-distortion according to the signal from the first coupled-line structure 11, or perform antenna calibration (AC) according to the signal from the second coupled-line structure 12.

[0065] Second, referring to Figures 4 to 11 , the embodiment of the present disclosure provides an antenna device 8.

[0066] The antenna device 8 implemented by the present disclosure has the above DPD circuit 1, so it has the DPD function itself, especially the function of "online DPD".

[0067] Referring to Figure 5 , the antenna device 8 of the embodiment of the present disclosure includes:

[0068] An antenna circuit 2, which includes multiple sub-transmission channels 211; each sub-transmission channel 211 is used to generate an output radio frequency signal at its output end according to the input digital signal;

[0069] A DPD circuit 1, which 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-transmission channels 211; the processing module 13 is connected to the first coupled-line structure 11 and is used to perform pre-distortion according to the signal from the first coupled-line structure 11.

[0070] It should be understood that referring to Figure 6 , the antenna device 8 of the embodiment of the present disclosure may also include other structures such as an antenna array 3.

[0071] For example, the antenna array 3 may include a plurality of transceiver antennas 31 arranged in an array, which are used to convert the output radio frequency signal generated by the antenna circuit 2 into a wireless signal in the form of an electromagnetic wave and transmit it, and receive the wireless signal and convert it into an input radio frequency signal for processing by the antenna circuit 2, etc., which will not be described in detail here.

[0072] In the embodiment of the present disclosure, the first coupling line structure 11 can collect the output radio frequency signals of all sub-transmission channels 211 and provide them to the processing module 13 for predistortion. Therefore, it does not need to use additional devices such as "detection antennas" and can achieve "online DPD" with good DPD effects. At the same time, the first coupling line structure 11 is just a lead wire rather than a device such as a coupler. That is, in the embodiment of the present disclosure, only some simple lead wires need to be set to achieve DPD without adding complex structures such as couplers. Therefore, it has low cost and is easy to use.

[0073] In some embodiments, the antenna circuit 2 includes a plurality of radio frequency channels 21, and each radio frequency channel 21 includes a plurality of sub-transmission channels 211;

[0074] The first coupling line structure 11 includes a first combining line 112 and a plurality of first coupling lines 111 corresponding to the radio frequency channels 21 one by one; each first coupling line 111 serially couples all the sub-transmission channels 211 of the corresponding radio frequency channel 21; the first combining line 112 combines all the first coupling lines 111 and is connected to the processing module 13.

[0075] As a specific implementation of the embodiment of the present disclosure, reference may be made to Figure 7 , each radio frequency channel 21 (or radio frequency link) includes a plurality of (such as M) wave control chips, and each wave control chip corresponds to a plurality of (such as K) sub-transmission channels 211. Therefore, each radio frequency channel 21 includes a plurality of (such as k*M) sub-transmission channels 211.

[0076] It should be understood that the embodiment of the present disclosure may also include a plurality of sub-reception channels 212. For example, reference may be made to Figure 2 、 Figure 3 , the sub-reception channels 212 and the sub-transmission channels 211 are in one-to-one correspondence, and some of the structures are "shared".

[0077] It should be understood that the specific structures of the radio frequency channels 21, wave control chips, sub-reception channels 212, sub-transmission channels 211, etc. in the embodiment of the present disclosure are diverse. For example, they may adopt the form of reference Figure 2 、 Figure 3 , or may be in the form of other related technologies, which will not be described in detail here.

[0078] As a way of the embodiment of the present disclosure, reference may be made to Figure 7, when the antenna circuit 2 includes multiple radio frequency channels 21, and each radio frequency channel 21 includes multiple sub-transmission channels 211, the output ends of all the sub-transmission channels 211 in each radio frequency channel 21 can be serially coupled through a first coupling line 111, so that the first coupling line 111 corresponds to the radio frequency channel 21 one by one, and multiple (such as N) first coupling lines 111 are then combined and connected by a first combining line 112, and the first combining line 112 is then connected to the processing module 13.

[0079] It can be seen that the sub-transmission channels 211 in each radio frequency channel 21 are usually closer and more convenient to connect. Therefore, the sub-transmission channels 211 in each radio frequency channel 21 can be serially coupled first, and then the connections of different radio frequency channels 21 can be combined.

[0080] In some embodiments, the first coupling line 111 is a microstrip line.

[0081] As a way of the embodiments of the present disclosure, the first coupling line 111 for realizing serial coupling above 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 radio frequency channel 21, it is more suitable to be realized in the form of a microstrip line.

[0082] It should be understood that other leads in the embodiments of the present disclosure, such as the first combining line 112, the second coupling line 121, the second combining line 122, etc., can also be in the form of microstrip lines; or, the leads in the embodiments of the present disclosure can also be in other forms, which will not be described in detail here.

[0083] In some embodiments, the DPD circuit 1 further includes:

[0084] A second coupling line structure 12, which couples the output ends of multiple sub-transmission channels 211;

[0085] A switch module 19, the first coupling line structure 11 and the second coupling line structure 12 are respectively connected to the processing module 13 through the switch module 19, and the switch module 19 is used to conduct the first coupling line structure 11 or the second coupling line structure 12 with the processing module 13;

[0086] The processing module 13 is further used to perform antenna calibration according to the signal from the second coupling line structure 12.

[0087] As a way of the embodiments of the present disclosure, the performance of the devices (such as DAC, upconverter, etc.) in the radio frequency channel 21 of the antenna circuit 2 will affect the amplitude and phase of the signals therein. Since there are inconsistencies in the devices in different radio frequency channels 21, the amplitudes and phases of the signals in different radio frequency channels 21 will be different. If the difference is too large, the consistency of the performance of each radio frequency channel 21 will be reduced.

[0088] Therefore, the antenna circuit 2 can also perform "antenna calibration (AC)", that is, different adjustments are made to each radio frequency channel 21 (such as different adjustments to the input digital signals) according to the differences in the signals in different radio frequency channels 21.

[0089] Therefore, with reference to Figure 6 , a second coupled line structure 12 can also be provided in the DPD circuit 1. The second coupled line structure 12 is also coupled to the output ends of multiple (not necessarily all) sub-transmission channels 211, and it and the first coupled 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 then connected to the processing module 13.

[0090] Thus, the switch module 19 can selectively conduct the first coupled line structure 11 or the second coupled line structure 12 to the processing module 13, that is, "selectively" input the signals of the first coupled line structure 11 or the second coupled line structure 12 to the processing module 13, so that the processing module 13 can perform pre-distortion according to the signal from the first coupled line structure 11, or perform antenna calibration (AC) according to the signal from the second coupled line structure 12.

[0091] Among them, since different signals are required for pre-distortion and antenna calibration, the switch module 19 does not have the situation of "simultaneously" conducting the first coupled line structure 11 and the second coupled line structure 12 to the processing module 13, but at most only conducts one of them to the processing module 13.

[0092] It should be understood that when neither pre-distortion nor antenna calibration is required, the switch module 19 can be completely turned off, that is, both the first coupled line structure 11 and the second coupled line structure 12 are disconnected from the processing module 13, so as to ensure that no signal enters the processing module 13.

[0093] Thus, the embodiment of the present disclosure can also implement the "antenna calibration" function. Moreover, this antenna calibration and DPD are processed by the same processing module 13, so there is no need to additionally set a processor, etc., but only a simple lead (the second coupled line structure 12) and a switch (the switch module) need to be added. Therefore, the structure of the antenna device 8 is simple and the cost is low.

[0094] It should be understood that the specific form of the processing module 13 in the embodiment of the present disclosure is diverse, as long as it can implement the function of DPD (or antenna calibration).

[0095] For example, with reference to Figure 7, the processing module 13 may include a downconverter, which is used to down-convert the signal from the first coupled line structure 11 (or the second coupled line structure 12) according to the local oscillator; the output end of the downconverter is connected to an analog-to-digital converter (ADC), which is used to convert the down-converted signal into a digital signal; the output end of the ADC is connected to a processing unit, and the processing unit performs corresponding calculations according to the digital signal converted by the ADC and the input digital signal to obtain how to compensate the antenna circuit 2, that is, to implement DPD (or antenna calibration).

[0096] Among them, the processing unit may be other separate devices outside the antenna circuit 2, so that the generated processing result can be input into the antenna circuit 2 to control the operation of the antenna circuit 2; or, the processing unit may also be a device with data processing capabilities originally in the antenna circuit 2, such as a baseband processing unit (BBU, Base Band Unite), etc.

[0097] It should be understood that the specific algorithms for antenna calibration in the embodiments of the present disclosure are diverse, such as those in related technologies can be adopted.

[0098] For example, when performing antenna calibration (AC), multiple sub-transmission channels 211 corresponding to the second coupled line structure 12 in multiple radio frequency channels 21 can be made to simultaneously generate output radio frequency signals under a predetermined input digital signal, and the switch module 19 is placed in a state where the second coupled line structure 12 is connected to the processing module 13, so as to collect the output radio frequency signals through the second coupled line structure 12 and input them into the processing module 13, and the processing module 13 determines how to adjust the input digital signals of each radio frequency channel 21 according to the collected signals and the corresponding input digital signals, for example, determines the amplitude-phase calibration coefficient c (or called calibration filter coefficient).

[0099] In some embodiments, the antenna circuit 2 includes multiple radio frequency channels 21, and each radio frequency channel 21 includes multiple sub-transmission channels 211;

[0100] The second coupled line structure 12 includes a second combining line 122 and multiple second coupled lines 121 corresponding to the radio frequency channels 21 one by one; each second coupled line 121 is connected to the output end of a sub-transmission channel 211 in the corresponding radio frequency channel 21, and the second combining line 122 combines and connects all the second coupled lines 121 and is connected to the switch module 19.

[0101] Refer to Figure 7, as a mode of the embodiments of the present disclosure, since antenna calibration is mainly used to compensate for the differences between different radio frequency channels 21, for antenna calibration, it is sufficient to collect the output radio frequency signals of one sub-transmission channel 211 in each radio frequency channel 21; therefore, the second coupling line structure 12 may include multiple (N) second coupling lines 121 corresponding one-to-one to the radio frequency channels 21, each second coupling line 121 is connected to the output end of a selected sub-transmission channel 211 in the corresponding radio frequency channel 21, and the second combining line 122 combines the second coupling lines 121 and is connected to the processing module 13 (specifically through the switch module 19).

[0102] In some embodiments, referring to Figure 8 , performing pre-distortion according to the signals from the first coupling line structure 11 includes:

[0103] A101. Control multiple sub-transmission channels 211 to sequentially generate output radio frequency signals at their respective output ends one by one.

[0104] A102. When each sub-transmission channel 211 generates an output radio frequency signal at its output end, obtain the DPD sampling signal of this sub-transmission channel 211 through the first coupling line structure 11.

[0105] A103. Perform pre-distortion on the input digital signal according to multiple DPD sampling signals and the input digital signals when each DPD sampling signal is collected.

[0106] As a mode of the embodiments of the present disclosure, when pre-distortion is to be performed, each sub-transmission channel 211 can be controlled to alternately generate output radio frequency signals under the drive of a specific input digital signal (Pin); and when each sub-transmission channel 211 generates an output radio frequency signal, this signal is introduced into the processing module 13 through the first coupling line structure 11.

[0107] Among them, the signal collected when each sub-transmission channel 211 outputs can be a phase-amplitude signal (Pfb) including amplitude and phase, that is, the DPD sampling signal of this sub-transmission channel 211; and when each Pfb is collected, the input digital signal (Pin) input to the sub-transmission channel 211 is also known.

[0108] Thus, the processing module 13 can calculate how to compensate the input digital signal according to multiple Pfbs (Pfb1, Pfb2... PfbM*N*K) and their corresponding Pins, and perform pre-distortion (or "pre-distortion training") on the subsequent input digital signals (such as baseband signals) to complete the DPD process.

[0109] It should be understood that if the DPD circuit 1 further includes a second coupling line structure 12 and a switch module 19, during pre-distortion, the switch module 19 should be placed in a state where the first coupling line structure 11 is connected to the processing module 13, while the connection between the second coupling line structure 12 and the processing module 13 is cut off.

[0110] 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"; however, at the moment of performing online DPD, the antenna device 8 may not be receiving or transmitting actual working signals, that is, online DPD can be performed during the "idle period" of the already put-into-use antenna device 8 to avoid affecting the normal operation of the antenna device 8.

[0111] In some embodiments, the input digital signals are the same when collecting each DPD sampling signal; referring to Figure 8 , pre-distorting the input digital signal (A103) based on multiple DPD sampling signals and the input digital signals when collecting each DPD sampling signal includes:

[0112] A1031. Determine the DPD coefficients based on multiple DPD sampling signals and the input digital signal.

[0113] A1032. Pre-distort the input digital signal based on the DPD coefficients.

[0114] As a way of the embodiment of the present disclosure, during the DPD process, all sub-transmission channels 211 can generate output radio frequency signals (i.e., amplitude-phase signals Pfb) according to the same input digital signal (Pin). Thus, based on this Pin and multiple Pfbs (Pfb1, Pfb2... PfbM*N*K), the corresponding DPD coefficients (Pindpd) can be calculated, and subsequently, the antenna circuit 2 can be pre-distorted (pre-distortion training) based on this Pindpd.

[0115] Among them, the specific method of calculating Pindpd based on the above Pin and multiple Pfbs (Pfb1, Pfb2... PfbM*N*K) is diverse.

[0116] For example, the digital processing module 13 can calculate a calibrated amplitude-phase signal (Pota') based on each Pfb and a predetermined amplitude-phase calibration coefficient c (or calibration filter coefficient), that is:

[0117] Pota' = c * Pfb;

[0118] Among them, c can be "a set of" coefficients for each sub-transmission channel 211, such as a matrix of M*N*k dimensions; correspondingly, the above multiplication operation of determining Pota' based on Pfb and c is also a matrix operation, and after splitting, it is equivalent to:

[0119] Poata1’ = Pfb1 * c1;

[0120] Pota2’ = Pfb2 * c2;

[0121] …

[0122] PotaN*M*k’ = PfbN*M*k * cN*M*k.

[0123] Thus, according to multiple Pfbs (Pfb1, Pfb2... PfbM*N*K), multiple Pota’s (Pota1’, Pota2’... PotaM*N*K’) can be calculated; further, the digital processing module 13 can compare Pin with multiple Pota’s (Pota1’, Pota2’... PotaM*N*k’) to calculate Pindpd.

[0124] Among them, Pindpd can also be “a group” of coefficients, such as a matrix in the dimension of M*N*k.

[0125] According to the above Pindpd, the original input digital signals (such as baseband signals) of each sub-transmission channel 211 can be fitted to obtain optimized input digital signals, and the output radio frequency signals and wireless signals generated according to the optimized input digital signals have good linearity.

[0126] Among them, the method of calculating Pindpd based on Pin and Pota’ is also diverse.

[0127] For example, referring to Figure 9 , as a way of 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 is compared with Pin to extract coefficients to obtain Pindpd.

[0128] Or, referring to Figure 10 , as another way of an embodiment of the present disclosure, it can also be to compare Pin with each Pota’ (Pota1, Pota2’... PotaM*N*K’) respectively (coefficient extraction) to obtain the sub-channel DPD coefficients corresponding to each sub-transmission channel 211, and then superimpose the sub-channel DPD coefficients to perform sub-channel coefficient extraction to obtain Pindpd.

[0129] Or, referring to Figure 11, normalize multiple Pota’ (Pota1’, Pota2’... PotaM*N*K’) data (such as amplitude normalization), and stack them in the form of a matrix, while Pin is also matrix-expanded into the form of a matrix, and then compare the two matrices to solve for Pindpd.

[0130] In some embodiments, referring to Figure 8 , the processing module 13 is further configured to perform initial sub-channel calibration, and the initial sub-channel calibration (A100) includes:

[0131] A1001. Control multiple sub-transmitting channels 211 to sequentially generate output radio frequency signals at their respective output ends one by one.

[0132] A1002. When each sub-transmitting channel 211 generates an output radio frequency signal at its output end, obtain the first calibration signal and the second calibration signal of the sub-transmitting channel 211 through the first coupling line structure 11.

[0133] Among them, the first calibration signal is the signal collected at the output end of the sub-transmitting channel 211, and the second calibration signal is the signal obtained after the signal collected by the detection antenna 9 at the air interface of the antenna device 8 is input to the processing module 13.

[0134] 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.

[0135] As a way of the embodiment of the present disclosure, referring to Figure 8 , the processing module 13 can also be used to perform initial calibration on each sub-transmitting channel 211 of the antenna device 8 before leaving the factory, that is, "initial sub-channel calibration", specifically calibrating the amplitude and phase of each sub-transmitting channel 211.

[0136] When performing initial sub-channel calibration, each sub-transmitting channel 211 can be controlled to alternately generate output radio frequency signals under a specific input digital signal (Pin), and the output radio frequency signal is input to the processing module 13 through the first coupling line structure 11 (and can also pass through the switch module 19) as the "first calibration signal", that is, the phase and amplitude signal (Pfb).

[0137] At the same time, when each sub-transmitting channel 211 generates an output radio frequency signal, a wireless signal in the form of an electromagnetic wave will be generated at the air interface of the antenna device 8 after passing 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 input to the processing module as the second calibration signal (Pota).

[0138] Thus, by comparing Pin, multiple Pfbs (Pfb1, Pfb2... PfbM*N*K), and multiple Potas (Pota1, Pota2... PotaM*N*K), the result for initial sub-channel calibration can be obtained. For example, the amplitude-phase calibration coefficient c as described above can be obtained, specifically a set of coefficients corresponding to each sub-transmission channel 211 respectively.

[0139] It should be understood that the structures and algorithms in the embodiments of the present disclosure are not limited to the forms of the above specific examples, and they can also adopt the methods in other related technologies, which will not be described in detail here.

[0140] The present disclosure has disclosed exemplary embodiments, and although specific terms are used, they are only used and should only be construed as having a general illustrative meaning and not for the purpose of limitation. In some instances, it will be apparent to those skilled in the art that, unless otherwise explicitly stated, the features, characteristics, and / or elements described in combination with a particular embodiment can be used alone or in combination with the features, characteristics, and / or elements described in combination with other embodiments. Therefore, those skilled in the art will understand that various changes in form and detail can be made without departing from the scope of the present disclosure as set forth by the appended claims.

Claims

1. A digital predistortion (DPD) circuit, wherein, 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 used to generate an output RF signal at its output end according to an input digital signal; A processing module connected to the first coupled line structure and used to perform pre - distortion according to the signal from the first coupled line structure.

2. The DPD circuit according to claim 1, wherein It further comprises: A second coupled line structure for coupling the output ends of 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 used to conduct the first coupled line structure or the second coupled line structure to the processing module; The processing module is further used to perform antenna calibration according to the signal from the second coupled line structure.

3. An antenna device, wherein, Comprising: An antenna circuit including multiple sub - transmission channels; Each of the sub - transmission channels is used to generate an output RF 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 multiple sub - transmission channels; the processing module is connected to the first coupled line structure and used 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 RF channels, and each RF channel includes multiple sub - transmission channels; The first coupled line structure includes a first combining line and multiple first coupled lines corresponding to the RF channels one by one; Each of the first coupled lines serially couples all the sub - transmission channels of the corresponding RF 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, The performing pre - distortion according to the signal from the first coupled line structure includes: Controlling multiple sub - transmission channels to sequentially generate the output RF signal at their respective output ends one by one; When each sub - transmission channel generates the output RF 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 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; the performing pre - distortion on the input digital signal according to multiple DPD sampling signals and the input digital signal when collecting each DPD sampling signal includes: Determining DPD coefficients according to 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 used to perform initial sub - channel calibration, and the initial sub - channel calibration includes: Controlling multiple sub - transmission channels to sequentially generate the output RF signal at their respective output ends one by one; When each of the sub-transmission channels generates the output RF signal at its output end, the first calibration signal and the second calibration signal of the sub-transmission channel are obtained through the first coupling line structure; the first calibration signal is the signal collected at the output end of the sub-transmission channel, and the second calibration signal is the signal obtained after the signal collected at the air interface of the antenna device by the detection antenna is input into the processing module; Calibrate each of the sub-transmission channels according to the first calibration signal, the second calibration signal, and the input digital signal when collecting each of the first calibration signals.

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

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

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