CN114567391B - Self-calibration method for downlink gain of remote radio unit - Google Patents
Self-calibration method for downlink gain of remote radio unit Download PDFInfo
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- CN114567391B CN114567391B CN202210240554.3A CN202210240554A CN114567391B CN 114567391 B CN114567391 B CN 114567391B CN 202210240554 A CN202210240554 A CN 202210240554A CN 114567391 B CN114567391 B CN 114567391B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/20—Monitoring; Testing of receivers
- H04B17/21—Monitoring; Testing of receivers for calibration; for correcting measurements
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/04—Wireless resource allocation
- H04W72/044—Wireless resource allocation based on the type of the allocated resource
- H04W72/0446—Resources in time domain, e.g. slots or frames
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/20—Control channels or signalling for resource management
- H04W72/23—Control channels or signalling for resource management in the downlink direction of a wireless link, i.e. towards a terminal
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
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Abstract
The invention provides a self-calibration method for the downlink gain of a remote radio unit, and relates to the technical field of wireless communication. The method comprises the following steps: in the TDD mode or the FDD mode, the self-calibration signal is inserted into a downlink time slot of the wireless frame structure. After traversing the downlink transmit chain, the self-calibration signal is coupled into the receive path or feedback path at the output of the filter. Thereby performing the gain self-calibration of the downlink according to the self-calibration signal received by coupling. And collecting self-calibration signals received in a receiving channel or a feedback channel. And carrying out data analysis on the received self-calibration signal, and obtaining a downlink gain curve by a linear fitting method. By the method, dependence on a frequency spectrograph during gain calibration of the remote radio unit on a production test line can be avoided, and therefore production test cost of the remote radio unit is reduced.
Description
Technical Field
The invention relates to the technical field of wireless communication, in particular to a self-calibration method for the downlink gain of a remote radio unit.
Background
In wireless communication, remote radio units (RRUs, remote Radio Unit) are core network elements in wireless communication networks, such as 2G, 3G, 4G, 5G and 6G, which are responsible for converting digital signals into analog radio frequency signals and transmitting the radio frequency signals into a wireless environment, and may also receive radio frequency signals and convert the received radio frequency signals into digital signals. By the 5G era, the frequency band defined by 3GPP (3 rd generation partnership project) is up to 26 frequency bands, the number of channels of the remote radio unit comprises 4 channels, 8 channels, 16 channels, 32 channels and 64 channels, and the output power of the remote radio unit ranges from good milliwatt level to 160W per channel. Therefore, the remote radio unit has a very rich variety of products. How to effectively reduce the production test cost of the remote radio unit becomes one of the key research objects of the industry.
Disclosure of Invention
The invention aims to provide a self-calibration method for the downlink gain of a remote radio unit, which can avoid the dependence on a spectrometer when the gain calibration of the remote radio unit is carried out on a production test line, thereby reducing the production test cost of the remote radio unit.
Embodiments of the present invention are implemented as follows:
the embodiment of the application provides a self-calibration method for the downlink gain of a remote radio unit, which comprises the following steps:
under the TDD mode or the FDD mode, the self-calibration signal is inserted into a downlink time slot of the wireless frame structure;
after traversing the downlink transmitting link, the self-calibration signal is coupled to a receiving channel or a feedback channel at the output end of the filter;
collecting self-calibration signals received in a receiving channel or a feedback channel;
and obtaining a gain curve of the downlink through linear fitting according to the received self-calibration signal.
In some embodiments of the present invention, the receiving channel includes a self-calibration receiving channel and a normal receiving channel, and the step of coupling the self-calibration signal to the receiving channel at the output end of the filter after traversing the downlink transmitting link includes:
self-calibration signals sequentially pass through digital up-conversion, peak clipping, digital predistortion, a digital-to-analog converter, a power amplifier and a filter to traverse a complete downlink transmitting link;
a first single-pole double-throw switch is arranged between the self-calibration receiving channel and the radio frequency receiving front end, and the first single-pole double-throw switch is controlled by a digital chip and is used for switching a self-calibration mode and a conventional receiving mode;
if the first single-pole double-throw switch is switched to the self-calibration mode, self-calibration signals are coupled to the self-calibration receiving channel through microstrip lines at the output end of the filter;
if the first single pole double throw switch is switched to the normal receiving mode, the self calibration signal is coupled to the normal receiving channel at the output end of the filter through the microstrip line.
In some embodiments of the present invention, the feedback path includes a self-calibrating feedback path, and the step of coupling the self-calibrating signal to the feedback path at the output of the filter after traversing the downlink transmission link includes:
a second single-pole double-throw switch is arranged between the output end of the filter and the self-calibration feedback channel, and the second single-pole double-throw switch is controlled by a digital chip and is used for switching the self-calibration mode and the conventional feedback mode;
if the second single-pole double-throw switch is switched to the self-calibration mode, the self-calibration signal is coupled to the self-calibration feedback channel through the microstrip line at the output end of the filter after sequentially passing through the digital up-conversion, peak clipping, digital predistortion, digital-to-analog converter, power amplifier and filter.
In some embodiments of the present invention, the feedback channel further includes a conventional feedback channel, and if the second single pole double throw switch is switched to the conventional feedback mode, the self-calibration signal is sequentially transmitted to the conventional feedback channel after digital up-conversion, peak clipping, digital predistortion, digital-to-analog converter and power amplifier.
In some embodiments of the present invention, the step of obtaining the gain curve of the downlink through linear fitting according to the received self-calibration signal includes:
according to the received self-calibration signal, the method is as follows
Performing linear fitting to obtain a gain curve of the downlink, wherein f 1 And f 2 Is two frequency points of known gain, G 1 Is f 1 Gain of G 2 Is f 2 F is the frequency point of the gain, and G (f) is the gain of f.
In some embodiments of the present invention, the self-calibration signal is received according to the formula
The step of performing a linear fit to obtain a gain curve for the downlink includes:
obtaining a self-calibration signal to be transmitted;
gain comparison is carried out on the self-calibration signal to be transmitted and the received self-calibration signal on a frequency domain so as to obtain a gain point diagram of discrete distribution on the whole working frequency band;
and linearly interpolating the gain point diagram to obtain a gain curve in the whole working bandwidth.
In some embodiments of the present invention, the step of inserting the self-calibration signal into the downlink timeslot of the radio frame structure in the TDD mode or the FDD mode includes:
generating self-calibration signals based on OFDM signals, and repeatedly transmitting the self-calibration signals in a downlink time slot time window, wherein the self-calibration length is one symbol length.
In some embodiments of the present invention, the step of generating the self-calibration signal based on the OFDM signal and repeatedly transmitting the self-calibration signal in the downlink slot time window includes:
in the multi-channel remote radio unit, based on the multi-carrier signal of the OFDM signal, each channel transmits different sub-carriers in the OFDM signal, wherein the sub-carriers are numbered as an arithmetic progression, and the tolerance of the arithmetic progression is consistent with the total number of the channels.
In some embodiments of the present invention, the step of coupling the self-calibration signal to the receiving channel or the feedback channel at the output of the filter after traversing the downlink transmission link includes:
in the multi-channel remote radio unit, an on-board combiner is arranged between the filter output ends of two adjacent channels for combining.
In some embodiments of the present invention, the step of collecting the received self-calibration signal in the receiving channel or the feedback channel includes:
data of one symbol length in a receiving channel or a feedback channel is collected.
Compared with the prior art, the embodiment of the invention has at least the following advantages or beneficial effects:
the invention provides a self-calibration method for the downlink gain of a remote radio unit, which comprises the following steps: in the TDD mode or the FDD mode, the self-calibration signal is inserted into a downlink time slot of the wireless frame structure. After traversing the downlink transmit chain, the self-calibration signal is coupled into the receive path or feedback path at the output of the filter. Thereby performing the gain self-calibration of the downlink according to the self-calibration signal received by coupling. And collecting self-calibration signals received in a receiving channel or a feedback channel. And carrying out data analysis on the received self-calibration signal, and obtaining a downlink gain curve by a linear fitting method. By the method, dependence on a frequency spectrograph during gain calibration of the remote radio unit on a production test line can be avoided, and therefore production test cost of the remote radio unit is reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a flowchart of a method for self-calibrating a downlink gain of a remote radio unit according to an embodiment of the present invention;
fig. 2 is a flowchart of a multiplexing receiving channel according to an embodiment of the present invention;
fig. 3 is a flowchart of a multiplexing feedback channel according to an embodiment of the present invention;
fig. 4 is a schematic diagram of self-calibration signals of a downlink channel 1 in a remote radio unit according to an embodiment of the present invention;
fig. 5 is a schematic diagram of self-calibration signals of a downlink channel 2 in a remote radio unit according to an embodiment of the present invention;
fig. 6 is a schematic diagram of self-calibration signals of the downlink channel 3 in the remote radio unit according to an embodiment of the present invention;
fig. 7 is a schematic diagram of self-calibration signals of the downlink channel 4 in the remote radio unit according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of a self-calibration signal for channel combination of a multi-channel remote radio unit according to an embodiment of the present invention;
FIG. 9 is a schematic diagram of power of a self-calibration signal to be transmitted according to an embodiment of the present invention;
FIG. 10 is a schematic diagram of power of a received self-calibration signal according to an embodiment of the present invention;
fig. 11 is a schematic diagram of a linearly fitted downlink gain curve according to an embodiment of the present invention.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, which are generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present application, as provided in the accompanying drawings, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like, if any, are used solely for distinguishing the description and are not to be construed as indicating or implying relative importance.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, the appearances of the element defined by the phrase "comprising one … …" do not exclude the presence of other identical elements in a process, method, article or apparatus that comprises the element.
In the description of the present application, it should be noted that, if the terms "upper," "lower," "inner," "outer," and the like indicate an azimuth or a positional relationship based on the azimuth or the positional relationship shown in the drawings, or an azimuth or the positional relationship that the product of the application is commonly put in use, it is merely for convenience of describing the present application and simplifying the description, and does not indicate or imply that the apparatus or element to be referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus should not be construed as limiting the present application.
In the description of the present application, it should also be noted that, unless explicitly stated and limited otherwise, the terms "disposed," "connected," and "connected" should be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art in a specific context.
Some embodiments of the present application are described in detail below with reference to the accompanying drawings. The various embodiments and features of the embodiments described below may be combined with one another without conflict.
Examples
Referring to fig. 1 to fig. 3, fig. 1 is a flowchart of a method for self-calibrating a downlink gain of a remote radio unit according to an embodiment of the present application, fig. 2 is a flowchart of a multiplexing receiving channel according to an embodiment of the present invention, and fig. 3 is a flowchart of a multiplexing feedback channel according to an embodiment of the present invention. The embodiment of the application provides a self-calibration method for the downlink gain of a remote radio unit, which comprises the following steps:
s110: under the TDD mode or the FDD mode, the self-calibration signal is inserted into a downlink time slot of the wireless frame structure;
the TDD mode refers to time division duplex, and the FDD mode refers to frequency division duplex. TDD and FDD are duplex technologies commonly used in mobile communication technologies, and need not be described in detail herein.
The frame structure is defined in the wireless communication system. The frame structure includes 3 parts: uplink time slot, downlink time slot and special time slot.
Specifically, the self-calibration signal is inserted before the digital up-conversion or low phy, i.e., part of the physical layer signal processing module, of the downlink.
By way of example, low phy refers to a portion of the physical layer signal processing functions such as IFFT (Invert Fast Fourier Transform, inverse fast fourier transform).
S120: after traversing the downlink transmitting link, the self-calibration signal is coupled to a receiving channel or a feedback channel at the output end of the filter;
specifically, the receive channel self-calibrated in this method multiplexes either a conventional receive channel or a conventional feedback channel. The self-calibration signal sequentially passes through digital up-conversion, peak clipping, digital predistortion, a digital-to-analog converter, a power amplifier and a filter to traverse the complete downlink transmitting link, and is then coupled to a receiving channel or a feedback channel at the output end of the filter, so that the gain self-calibration of the downlink is performed according to the coupled received signal.
S130: collecting self-calibration signals received in a receiving channel or a feedback channel;
specifically, a conventional receiving channel or a conventional feedback channel in the multiplexing remote radio unit receives self-calibration signals, the self-calibration signals are subjected to digital down-conversion sequentially through an analog-to-digital converter, and a digital chip (FPGA or ASIC) collects the self-calibration signals received in the receiving channel or the feedback channel and stores the self-calibration signals in the DDR.
The digital chip may be an FPGA or an ASIC, among others.
S140: and obtaining a gain curve of the downlink through linear fitting according to the received self-calibration signal.
Specifically, the received self-calibration signal is subjected to data analysis, and a gain curve of a downlink is obtained through a linear fitting method. By the method, dependence on a frequency spectrograph during gain calibration of the remote radio unit on a production test line can be avoided, and therefore production test cost of the remote radio unit is reduced.
In the implementation process, in the multi-channel remote radio unit, the self-calibration signal is generated based on the OFDM signal, and each subcarrier has the same power and the same amplitude based on the multi-carrier signal of the OFDM signal, and referring to fig. 9, fig. 9 shows a schematic power diagram of the self-calibration signal to be transmitted according to an embodiment of the present invention. And each channel uses a different subcarrier in the OFDM signal, the subcarriers being orthogonal between channels. When the data stored in the DDR are analyzed, because the self-calibration signals on the multiple channels are positioned on different subcarriers, the orthogonality of the self-calibration signals among the multiple channels can be utilized to realize the simultaneous gain calibration of the multiple channels, so that the corresponding gain curve of each downlink channel is obtained, and the complexity of signal processing is reduced. The method not only eliminates the dependence on the spectrometer when the gain calibration is carried out on the production test line, efficiently realizes the gain calibration of the downlink of the remote radio unit, reduces the cost of production test, but also can realize the simultaneous calibration of a plurality of channels through the signal characteristics of OFDM, and greatly improves the production efficiency. And a combiner is arranged between two adjacent channels, the self-calibration signals after multi-channel coupling are combined by the combiner, and the signals on different channels are mutually orthogonal and positioned on different subcarriers, so that finally, the combined signals form an OFDM signal spectrum with complete bandwidth.
Referring to fig. 10, fig. 10 is a schematic diagram illustrating a received self-calibration signal power according to an embodiment of the invention. Specifically, the generation is performed according to the formula y=x+g, where x is the self-calibration signal to be transmitted, y is the received self-calibration signal, and G is the gain of the downlink. In the simulation, an average gain of 10 is assumed.
In some implementations of this embodiment, the receiving channel includes a self-calibrating receiving channel and a regular receiving channel, and the step of coupling the self-calibrating signal to the receiving channel at the output of the filter after traversing the downlink transmitting link includes:
self-calibration signals sequentially pass through digital up-conversion, peak clipping, digital predistortion, a digital-to-analog converter, a power amplifier and a filter to traverse a complete downlink transmitting link;
a first single-pole double-throw switch is arranged between the self-calibration receiving channel and the radio frequency receiving front end, and the first single-pole double-throw switch is controlled by a digital chip and is used for switching a self-calibration mode and a conventional receiving mode;
if the first single-pole double-throw switch is switched to the self-calibration mode, self-calibration signals are coupled to the self-calibration receiving channel through microstrip lines at the output end of the filter;
if the first single pole double throw switch is switched to the normal receiving mode, the self calibration signal is coupled to the normal receiving channel at the output end of the filter through the microstrip line.
In the implementation process, when the self-calibration receiving channel multiplexes the conventional receiving channel in the remote radio unit, a first single-pole double-throw switch is arranged between the self-calibration receiving channel and the front radio receiving end, if the first single-pole double-throw switch is switched to the self-calibration mode, self-calibration signals are coupled through microstrip lines at the output end of the filter, and then the coupled self-calibration signals are sent to the data acquisition module for acquisition after being subjected to analog-to-digital converter and digital down conversion.
Wherein the digital up-conversion serves to increase the signal sampling rate and obtain the desired performance of the received baseband signal by means of interpolation. The effect of peak clipping is to reduce the peak-to-average ratio of the signal. The digital predistortion has the function of improving the nonlinearity of the power amplifier, and the basic principle is that a predistortion signal is generated according to a feedback signal of a transmitting feedback channel and is superimposed on a forward input signal, so that the purpose of compensating the power amplifier distortion is achieved. The DAC, i.e. the digital-to-analog converter, functions to convert a digital signal into an analog signal. The function of the power amplifier is to amplify the signal to a desired power level. The filter functions to reduce the portion of the whole band other than the useful signal to a sufficiently low level. The on-board combiner is used for combining and transmitting multiple signals. The ADC, i.e. the analog-to-digital converter, functions to convert an analog signal into a digital signal. The effect of digital down-conversion is to decimate the sampled signal to reduce the signal sampling rate and achieve the desired performance. The function of Balun is to increase the signal immunity, and the function of BPF is to let only signals processed by Balun pass.
In some implementations of this embodiment, the feedback path includes a self-calibrating feedback path, and the step of coupling the self-calibrating signal to the feedback path at the output of the filter after traversing the downlink transmit chain includes:
a second single-pole double-throw switch is arranged between the output end of the filter and the self-calibration feedback channel, and the second single-pole double-throw switch is controlled by a digital chip and is used for switching the self-calibration mode and the conventional feedback mode;
if the second single-pole double-throw switch is switched to the self-calibration mode, the self-calibration signal is coupled to the self-calibration feedback channel through the microstrip line at the output end of the filter after sequentially passing through the digital up-conversion, peak clipping, digital predistortion, digital-to-analog converter, power amplifier and filter.
In some implementations of this embodiment, the feedback channel further includes a conventional feedback channel, and if the second single pole double throw switch is switched to the conventional feedback mode, the self-calibration signal is sequentially transmitted to the conventional feedback channel after digital up-conversion, peak clipping, digital predistortion, digital-to-analog converter, and power amplifier.
Referring to fig. 11, fig. 11 is a schematic diagram of a linearly fitted downlink gain curve according to an embodiment of the present invention. In some implementations of this embodiment, the step of obtaining the gain curve of the downlink through linear fitting according to the received self-calibration signal includes:
according to the received self-calibration signal, the method is as follows
Performing linear fitting to obtain a gain curve of the downlink, wherein f 1 And f 2 Is two frequency points of known gain, G 1 Is f 1 Gain of G 2 Is f 2 F is the frequency point of the gain, and G (f) is the gain of f.
In some implementations of the present embodiment, the above-mentioned self-calibration signal is received according to the formula
The step of performing a linear fit to obtain a gain curve for the downlink includes:
obtaining a self-calibration signal to be transmitted;
gain comparison is carried out on the self-calibration signal to be transmitted and the received self-calibration signal on a frequency domain so as to obtain a gain point diagram of discrete distribution on the whole working frequency band;
and linearly interpolating the gain point diagram to obtain a gain curve in the whole working bandwidth.
Referring to fig. 4 to 8, fig. 4 is a schematic diagram of self-calibration signals of a downlink channel 1 in a remote radio unit according to an embodiment of the present invention, fig. 5 is a schematic diagram of self-calibration signals of a downlink channel 2 in a remote radio unit according to an embodiment of the present invention, fig. 6 is a schematic diagram of self-calibration signals of a downlink channel 3 in a remote radio unit according to an embodiment of the present invention, fig. 7 is a schematic diagram of self-calibration signals of a downlink channel 4 in a remote radio unit according to an embodiment of the present invention, and fig. 8 is a schematic diagram of self-calibration signals of channel combination of a multi-channel remote radio unit according to an embodiment of the present invention. Wherein, each channel selects different sub-carriers, and the sub-carriers are mutually orthogonal in consideration of the characteristics of OFDM signals, so that the signals between channels have good capability of resisting the interference between channels. And the subcarrier number selected by each channel is an arithmetic sequence taking the number of the channels as a difference value.
In some implementations of this embodiment, the step of inserting the self-calibration signal into the downlink timeslot of the radio frame structure in the TDD mode or the FDD mode includes:
generating self-calibration signals based on OFDM signals, and repeatedly transmitting the self-calibration signals in a downlink time slot time window, wherein the self-calibration length is one symbol length.
The bandwidth of the signal is illustratively dependent on the operating bandwidth that the remote radio unit is required to support. For example, an operating bandwidth of 100MHz, an OFDM signal with a total bandwidth of 100MHz is generated. The subcarrier spacing may be as defined in 3 GPP: 15KHz, 30KHz and 60KHz. Other values are possible, depending on the requirements at which the gain curve is fitted.
In some implementations of this embodiment, the step of generating the self-calibration signal based on the OFDM signal and repeatedly transmitting the self-calibration signal within the downlink slot time window includes:
in the multi-channel remote radio unit, based on the multi-carrier signal of the OFDM signal, each channel transmits different sub-carriers in the OFDM signal, wherein the sub-carriers are numbered as an arithmetic progression, and the tolerance of the arithmetic progression is consistent with the total number of the channels.
In some implementations of this embodiment, after the self-calibration signal traverses the downlink transmit chain, the step of coupling the self-calibration signal to the receive channel or the feedback channel at the output of the filter includes:
in the multi-channel remote radio unit, an on-board combiner is arranged between the filter output ends of two adjacent channels for combining.
In some implementations of this embodiment, the step of collecting the received self-calibration signal in the receiving channel or the feedback channel includes:
data of one symbol length in a receiving channel or a feedback channel is collected. Specifically, the processing time delay of the whole remote radio unit is basically stable, so that the expected signal can be accurately acquired.
In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other manners as well. The apparatus embodiments described above are merely illustrative, for example, flow diagrams and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
In addition, the functional modules in the embodiments of the present application may be integrated together to form a single part, or each module may exist alone, or two or more modules may be integrated to form a single part.
The functions, if implemented in the form of software functional modules and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the same, but rather, various modifications and variations may be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.
It will be evident to those skilled in the art that the present application is not limited to the details of the foregoing illustrative embodiments, and that the present application may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Claims (8)
1. The method for self-calibrating the downlink gain of the remote radio unit is characterized by comprising the following steps of:
under the TDD mode or the FDD mode, the self-calibration signal is inserted into a downlink time slot of the wireless frame structure;
after traversing the downlink transmitting link, the self-calibration signal is coupled to a receiving channel or a feedback channel at the output end of the filter;
collecting self-calibration signals received in the receiving channel or the feedback channel;
obtaining a gain curve of a downlink through linear fitting according to the received self-calibration signal;
the receiving channel comprises a self-calibration receiving channel and a conventional receiving channel, and the step of coupling the self-calibration signal to the receiving channel at the output end of the filter after traversing the downlink transmitting link comprises the following steps:
the self-calibration signal sequentially passes through digital up-conversion, peak clipping, digital predistortion, a digital-to-analog converter, a power amplifier and a filter so as to traverse a complete downlink transmitting link;
a first single-pole double-throw switch is arranged between the self-calibration receiving channel and the radio frequency receiving front end, and the first single-pole double-throw switch is controlled by a digital chip and is used for switching a self-calibration mode and a conventional receiving mode;
if the first single-pole double-throw switch is switched to the self-calibration mode, the self-calibration signal is coupled to the self-calibration receiving channel through a microstrip line at the output end of the filter;
if the first single-pole double-throw switch is switched to the normal receiving mode, the self-calibration signal is coupled to the normal receiving channel through a microstrip line at the output end of the filter;
the feedback path comprises a self-calibrating feedback path, and the step of coupling to the feedback path at the output of the filter after the self-calibrating signal traverses the downlink transmit chain comprises:
a second single-pole double-throw switch is arranged between the output end of the filter and the self-calibration feedback channel, and the second single-pole double-throw switch is controlled by a digital chip and is used for switching a self-calibration mode and a conventional feedback mode;
if the second single-pole double-throw switch is switched to the self-calibration mode, the self-calibration signal is coupled to the self-calibration feedback channel through a microstrip line at the output end of the filter after sequentially passing through digital up-conversion, peak clipping, digital predistortion, a digital-to-analog converter, a power amplifier and the filter.
2. The method according to claim 1, wherein the feedback channel further comprises a normal feedback channel, and if the second single pole double throw switch is switched to the normal feedback mode, the self-calibration signal is sequentially transmitted to the normal feedback channel after digital up-conversion, peak clipping, digital predistortion, digital-to-analog converter, and power amplification.
3. The method for self-calibration of the downlink gain of a remote radio unit according to claim 1, wherein said step of obtaining a gain curve of the downlink by linear fitting based on the received self-calibration signal comprises:
according to the received self-calibration signal, the method is as follows
Performing linear fitting to obtain a gain curve of the downlink, wherein f 1 And f 2 Is two frequency points of known gain, G 1 Is f 1 Gain of G 2 Is f 2 F is the frequency point of the gain, and G (f) is the gain of f.
4. The method of self-calibration of the downlink gain of a remote radio unit according to claim 3, wherein said self-calibration signal is formulated according to the received self-calibration signal
The step of performing a linear fit to obtain a gain curve for the downlink includes:
obtaining a self-calibration signal to be transmitted;
gain comparison is carried out on the self-calibration signal to be transmitted and the received self-calibration signal on a frequency domain so as to obtain a gain point diagram of discrete distribution on the whole working frequency band;
and linearly interpolating the gain point diagram to obtain a gain curve in the whole working bandwidth.
5. The method for self-calibration of the downlink gain of a remote radio unit according to claim 1, wherein the step of inserting the self-calibration signal into the downlink slot of the radio frame structure in the TDD mode or the FDD mode comprises:
generating a self-calibration signal based on an OFDM signal, and repeatedly transmitting the self-calibration signal in a downlink time slot time window, wherein the self-calibration length is one symbol length.
6. The method for self-calibrating the downlink gain of a remote radio unit according to claim 5, wherein said generating a self-calibration signal based on an OFDM signal and repeatedly transmitting said self-calibration signal within a downlink slot time window comprises:
in the multi-channel remote radio unit, based on the multi-carrier signal of the OFDM signal, each channel transmits different subcarriers in the OFDM signal, wherein the subcarriers are numbered as an arithmetic progression, and the tolerance of the arithmetic progression is consistent with the total number of channels.
7. The method of claim 1, wherein the step of coupling the self-calibration signal to the receiving channel or the feedback channel at the output of the filter after traversing the downlink transmission link comprises:
in the multi-channel remote radio unit, an on-board combiner is arranged between the filter output ends of two adjacent channels for combining.
8. The method of self-calibration of the downlink gain of a remote radio unit according to claim 1, wherein the step of collecting the received self-calibration signal in the receiving channel or the feedback channel comprises:
and collecting the data of one symbol length in the receiving channel or the feedback channel.
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