CN114567391A - Self-calibration method for radio remote unit downlink gain - Google Patents
Self-calibration method for radio remote unit downlink gain Download PDFInfo
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- CN114567391A CN114567391A CN202210240554.3A CN202210240554A CN114567391A CN 114567391 A CN114567391 A CN 114567391A CN 202210240554 A CN202210240554 A CN 202210240554A CN 114567391 A CN114567391 A CN 114567391A
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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
Abstract
The invention provides a self-calibration method for a radio remote unit downlink gain, and relates to the technical field of wireless communication. The method comprises the following steps: and inserting the self-calibration signal into a downlink time slot of a radio frame structure in a TDD mode or an FDD mode. After traversing the downlink transmission link, the self-calibration signal is coupled to the receiving channel or the feedback channel at the output end of the filter. Thereby carrying out the gain self-calibration of the downlink according to the coupled received self-calibration signal. And collecting a self-calibration signal received in a receiving channel or a feedback channel. And carrying out data analysis on the received self-calibration signal, and obtaining a gain curve of a downlink by a linear fitting method. The method can avoid the dependence on a frequency spectrograph 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.
Description
Technical Field
The invention relates to the technical field of wireless communication, in particular to a self-calibration method for a downlink gain of a radio remote unit.
Background
In wireless communication, a Remote Radio Unit (RRU) is a core network element in a wireless communication network, such as 2G, 3G, 4G, 5G, and 6G, and is responsible for converting a digital signal into an analog Radio signal and transmitting the Radio signal to a wireless environment, and meanwhile, may also receive a Radio signal and convert the received Radio signal into a digital signal. By the age 5G, the frequency band defined by 3GPP (3rd generation partnership project) reaches 26 frequency bands, the number of channels of the remote radio unit includes 4 channels, 8 channels, 16 channels, 32 channels and 64 channels, and the output power of the remote radio unit is from milliwatt to 160 watts per channel. Therefore, the product types of the radio remote unit are very rich. How to effectively reduce the production and test cost of the remote radio unit becomes one of the key research objects in the industry.
Disclosure of Invention
The invention aims to provide a method for self-calibrating the downlink gain of a radio remote unit, which can avoid the dependence on a frequency spectrograph when the gain calibration of the radio remote unit is carried out on a production test line, thereby reducing the production test cost of the radio remote unit.
The embodiment of the invention is realized by the following steps:
the embodiment of the application provides a self-calibration method for a radio remote unit downlink gain, which comprises the following steps:
inserting a self-calibration signal into a downlink time slot of a wireless frame structure in a TDD mode or an FDD mode;
after traversing a downlink transmission link, the self-calibration signal is coupled to a receiving channel or a feedback channel at the output end of the filter;
collecting a self-calibration signal received in a receiving channel or a feedback channel;
and obtaining a gain curve of a 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:
the self-calibration signal sequentially passes through a digital up-conversion circuit, a peak clipping circuit, a digital pre-distortion circuit, a digital-to-analog converter, a power amplifier and a filter to traverse a complete downlink transmission 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 a self-calibration receiving channel at the output end of the filter through a microstrip line;
if the first single-pole double-throw switch is switched to a normal receiving mode, the self-calibration signal is coupled to a normal receiving channel at the output end of the filter through a microstrip line.
In some embodiments of the present invention, the feedback path includes a self-calibration feedback path, and the step of coupling the self-calibration signal to the feedback path at the output end 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 the 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 the microstrip line at the output end of the filter after sequentially passing through the digital up-conversion, the peak clipping, the digital pre-distortion, the digital-to-analog converter, the power amplifier and the 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 pre-distortion, a digital-to-analog converter and a power amplifier.
In some embodiments of the present invention, the step of obtaining a gain curve of a downlink by linear fitting according to the received self-calibration signal includes:
according to formula based on received self-calibration signal
Performing linear fitting to obtain a gain curve of a downlink, wherein f1And f2Is two frequency points of known gain, G1Is f1Gain of (G)2Is f2F is the frequency point of the obtained gain, and G (f) is the gain of f.
In some implementations of the inventionIn one embodiment, the self-calibration signal is received according to a formula
The step of performing linear fitting to obtain a gain curve of the downlink comprises:
acquiring 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 in a frequency domain, so that a gain point diagram which is discretely distributed in the whole working frequency band is obtained;
and carrying out linear interpolation on 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:
and generating a self-calibration signal based on the 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.
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 within the downlink time slot time window includes:
in the multichannel radio remote unit, each channel transmits different subcarriers in the OFDM signal based on a multicarrier signal of 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 the channels.
In some embodiments of the present invention, the step of coupling the self-calibration signal to the receive path or the feedback path at the output end of the filter after traversing the downlink transmit link includes:
in the multi-channel radio remote unit, an on-board combiner is arranged between the output ends of the filters 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 radio remote unit, which comprises the following steps: and inserting a self-calibration signal into a downlink time slot of a radio frame structure in a TDD mode or an FDD mode. After traversing the downlink transmission link, the self-calibration signal is coupled to the receiving channel or the feedback channel at the output end of the filter. Thereby carrying out the gain self-calibration of the downlink according to the coupled received self-calibration signal. And collecting a self-calibration signal received in a receiving channel or a feedback channel. And carrying out data analysis on the received self-calibration signal, and obtaining a gain curve of a downlink by a linear fitting method. The method can avoid the dependence on a frequency spectrograph when the gain calibration of the radio remote unit is carried out on a production test line, thereby reducing the production test cost of the radio remote unit.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a flowchart of a method for self-calibration of a downlink gain of a remote radio unit according to an embodiment of the present invention;
fig. 2 is a flowchart of multiplexing a 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 a self-calibration signal of a downlink channel 1 in a radio remote unit according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a self-calibration signal of a downlink channel 2 in a radio remote unit according to an embodiment of the present invention;
fig. 6 is a schematic diagram of a self-calibration signal of a downlink channel 3 in a radio remote unit according to an embodiment of the present invention;
fig. 7 is a schematic diagram of a self-calibration signal of a downlink channel 4 in a radio remote unit according to an embodiment of the present invention;
fig. 8 is a schematic diagram of a channel-merged self-calibration signal of a multi-channel radio remote 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 the power of a received self-calibration signal according to an embodiment of the present invention;
fig. 11 is a schematic diagram of a downlink gain curve after linear fitting according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in 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 obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like, if appearing, are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.
It is noted that, herein, relational terms such as first and second, and the like may be 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. Also, 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 presence of an element identified by the phrase "comprising an … …" does not exclude the presence of additional like elements in any 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", etc. are used to indicate an orientation or positional relationship based on that shown in the drawings or that the application product is usually placed in use, the description is merely for convenience and simplicity, and it is not intended to indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore should not be construed as limiting the present application.
In the description of the present application, it should also be noted that, unless otherwise explicitly stated or limited, the terms "disposed" and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.
Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments described below and the individual features of the embodiments can be combined with one another without conflict.
Examples
Referring to fig. 1 to fig. 3, fig. 1 is a flowchart illustrating a self-calibration method for a downlink gain of a remote radio unit according to an embodiment of the present invention, fig. 2 is a flowchart illustrating a multiplexing reception channel according to an embodiment of the present invention, and fig. 3 is a flowchart illustrating a multiplexing feedback channel according to an embodiment of the present invention. The embodiment of the application provides a self-calibration method for a radio remote unit downlink gain, which comprises the following steps:
s110: inserting a self-calibration signal into a downlink time slot of a wireless frame structure in a TDD mode or an FDD mode;
the TDD mode refers to time division duplex, and the FDD mode refers to frequency division duplex. TDD and FDD are both duplexing techniques commonly used by mobile communication technologies and need not be described herein.
In the wireless communication system, a frame structure definition method is adopted. The frame structure includes 3 parts: uplink time slot, downlink time slot and special time slot.
Specifically, a 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.
Illustratively, low phy refers to a part of the physical layer signal processing function, such as IFFT (inverse Fast Fourier Transform).
S120: after traversing a downlink transmission link, the self-calibration signal is coupled to a receiving channel or a feedback channel at the output end of the filter;
specifically, the self-calibrated receive channel in the method multiplexes a conventional receive channel or a conventional feedback channel. The self-calibration signal sequentially passes through a digital up-conversion circuit, a peak clipping circuit, a digital pre-distortion circuit, a digital-to-analog converter, a power amplifier and a filter to traverse a complete downlink transmission link, and then is 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 carried out according to the coupled received signal.
S130: collecting a self-calibration signal received in a receiving channel or a feedback channel;
specifically, a conventional receiving channel or a conventional feedback channel in the multiplexing radio remote unit receives a self-calibration signal, the self-calibration signal sequentially passes through an analog-to-digital converter and a digital down-conversion, and a digital chip (FPGA or ASIC) collects the self-calibration signal received in the receiving channel or the feedback channel and stores the self-calibration signal in the DDR.
The digital chip can be an FPGA or an ASIC.
S140: and obtaining a gain curve of a downlink by linear fitting according to the received self-calibration signal.
Specifically, data analysis is performed on the received self-calibration signal, and a gain curve of a downlink is obtained through a linear fitting method. The method can avoid the dependence on a frequency spectrograph 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.
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, specifically referring to fig. 9, where fig. 9 is 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, with the subcarriers between channels being orthogonal. When data stored in the DDR is analyzed, due to the fact that self-calibration signals on multiple channels are located on different subcarriers, gains of the multiple channels can be calibrated simultaneously by utilizing orthogonality of the self-calibration signals among the multiple channels, and therefore a corresponding gain curve of each downlink channel is obtained, and complexity of signal processing is reduced. The method not only eliminates the dependence on a frequency spectrograph when gain calibration is carried out on a production test line, efficiently realizes the gain calibration on the radio frequency remote unit downlink, reduces the production test cost, but also can realize the simultaneous calibration on 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, and the combiner is used for combining the multi-channel coupled self-calibration signals, and because the signals on different channels are orthogonal and positioned on different subcarriers, the combined signals form an OFDM signal spectrum with complete bandwidth.
Referring to fig. 10, fig. 10 is a schematic diagram illustrating a power of a received self-calibration signal according to an embodiment of the invention. Specifically, the self-calibration signal is generated 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 illustration, the average gain is assumed to be 10.
In some embodiments of this embodiment, the receiving path includes a self-calibration receiving path and a normal receiving path, and the step of coupling the self-calibration signal to the receiving path at the output end of the filter after traversing the downlink transmitting link includes:
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 a complete downlink transmission 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 a 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 a normal receiving mode, the self-calibration signal is coupled to a normal receiving channel at the output end of the filter through a microstrip line.
In the implementation process, when the self-calibration receiving channel multiplexes a 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 end of the radio receiving, if the first single-pole double-throw switch is switched to a self-calibration mode, a self-calibration signal is coupled at the output end of the filter through a microstrip line, and then the coupled self-calibration signal is sent to a data acquisition module for acquisition after passing through an analog-to-digital converter and digital down-conversion.
The digital up-conversion is used to improve the sampling rate of the received baseband signal by means of interpolation and to obtain the desired performance. The peak clipping effect 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 transmission feedback channel and is superposed 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 power amplifier functions to amplify the signal to a desired power level. The filter functions to reduce other parts than the useful signal over the entire frequency band to a sufficiently low level. The on-board combiner is used for combining and transmitting the multipath 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 interference rejection capability, and the function of BPF is to pass only the signal processed by Balun.
In some embodiments of this embodiment, the feedback path includes a self-calibration feedback path, and the step of coupling the self-calibration signal to the feedback path at the output end 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 the 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 a self-calibration feedback channel through a microstrip line at the output end of the filter after sequentially passing through a digital up-conversion, a peak clipping, a digital predistortion, a digital-to-analog converter, a power amplifier and the filter.
In some embodiments 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 pre-distortion, a digital-to-analog converter, and a power amplifier.
Referring to fig. 11, fig. 11 is a schematic diagram illustrating a downlink gain curve after linear fitting according to an embodiment of the present invention. In some embodiments of this embodiment, the step of obtaining the gain curve of the downlink by linear fitting according to the received self-calibration signal includes:
according to formula based on received self-calibration signal
Performing linear fitting to obtain a gain curve of a downlink, wherein f1And f2Is two frequency points of known gain, G1Is f1Gain of (G)2Is f2F is the frequency point of the obtained gain, and G (f) is the gain of f.
In some embodiments of this embodiment, the self-calibration signal is received according to a formula
The step of performing linear fitting to obtain a gain curve of the downlink comprises:
acquiring 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 in a frequency domain, so that a gain point diagram which is discretely distributed in the whole working frequency band is obtained;
and carrying out linear interpolation on 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 illustrating a self-calibration signal of a downlink channel 1 in a remote radio unit according to an embodiment of the present invention, fig. 5 is a schematic diagram illustrating a self-calibration signal of a downlink channel 2 in a remote radio unit according to an embodiment of the present invention, fig. 6 is a schematic diagram illustrating a self-calibration signal of a downlink channel 3 in a remote radio unit according to an embodiment of the present invention, fig. 7 is a schematic diagram illustrating a self-calibration signal 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 illustrating a self-calibration signal of channel combination of a multi-channel remote radio unit according to an embodiment of the present invention. Different subcarriers are selected for each channel, the characteristics of OFDM signals are considered, and the subcarriers are mutually orthogonal, so that the signals among the channels have good capacity of resisting interference among the 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 embodiments 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:
and generating a self-calibration signal based on the 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.
Illustratively, the bandwidth of the signal depends on the operating bandwidth that the remote radio unit needs to support. For example, 100MHz of operating bandwidth, an OFDM signal having a total bandwidth of 100MHz is generated. The subcarrier spacing may be as defined in 3 GPP: 15KHz, 30KHz and 60 KHz. Other values are possible depending on the requirements when fitting the gain curve.
In some embodiments 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 time slot time window includes:
in the multichannel radio remote unit, each channel transmits different subcarriers in the OFDM signal based on a multicarrier signal of the OFDM signal, wherein the subcarrier number is an arithmetic progression, and the tolerance of the arithmetic progression is consistent with the total number of the channels.
In some embodiments of this embodiment, after the self-calibration signal traverses the downlink transmission link, the step of coupling to the receive path or the feedback path at the output end of the filter includes:
in the multi-channel radio remote unit, an on-board combiner is arranged between the output ends of the filters of two adjacent channels for combining.
In some embodiments 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, because the processing delay of the whole remote radio unit is basically stable, 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 ways. The apparatus embodiments described above are merely illustrative, and for example, the flowchart 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 that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
In addition, functional modules in the embodiments of the present application may be integrated together to form an independent part, or each module may exist alone, or two or more modules may be integrated to form an independent part.
The functions may be stored in a computer-readable storage medium if they are implemented in the form of software functional modules and sold or used as separate products. Based on such understanding, the technical solutions of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute 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), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
It will be evident to those skilled in the art that the 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 attributes 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 (10)
1. A method for self-calibration of the downlink gain of a remote radio unit is characterized by comprising the following steps:
inserting a self-calibration signal into a downlink time slot of a wireless frame structure in a TDD mode or an FDD mode;
after traversing a downlink transmission link, the self-calibration signal is coupled to a receiving channel or a feedback channel at the output end of the filter;
collecting a self-calibration signal received in the receiving channel or the feedback channel;
and obtaining a gain curve of a downlink by linear fitting according to the received self-calibration signal.
2. The method of claim 1, wherein the receive path comprises a self-calibration receive path and a normal receive path, and the step of coupling the self-calibration signal to the receive path at the output of the filter after traversing the downlink transmit path comprises:
the self-calibration signal sequentially passes through a digital up-conversion circuit, a peak clipping circuit, a digital pre-distortion circuit, a digital-to-analog converter, a power amplifier and a filter to traverse a complete downlink transmission 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;
and 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 a microstrip line.
3. The method of claim 1, wherein the feedback path comprises a self-calibration feedback path, and the step of coupling the self-calibration signal to the feedback path at the output of the filter after traversing 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 a digital up-conversion, a peak clipping, a digital pre-distortion, a digital-to-analog converter, a power amplifier and the filter.
4. The method of claim 3, wherein the feedback channel further comprises a conventional feedback channel, and if the second single-pole double-throw switch switches to the conventional feedback mode, the self-calibration signal is transmitted to the conventional feedback channel after digital up-conversion, peak clipping, digital pre-distortion, digital-to-analog converter, and power amplification in sequence.
5. The method of claim 1, wherein the step of obtaining the downlink gain curve of the radio remote unit by linear fitting according to the received self-calibration signal comprises:
according to formula based on received self-calibration signal
Performing linear fitting to obtain a gain curve of a downlink, wherein f1And f2Is two frequency points of known gain, G1Is f1Gain of (G), G2Is f2F is the frequency point of the obtained gain, and G (f) is the gain of f.
6. The method of claim 5, wherein the self-calibration is based on a received self-calibration signal and according to a formula
The step of performing linear fitting to obtain a gain curve of the downlink comprises:
acquiring 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 in a frequency domain, so that a gain point diagram which is discretely distributed in the whole working frequency band is obtained;
and carrying out linear interpolation on the gain point diagram to obtain a gain curve in the whole working bandwidth.
7. The method of claim 1, wherein the step of inserting a self-calibration signal into a downlink timeslot of a radio frame structure in TDD mode or FDD mode comprises:
the method comprises the steps of 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.
8. The method of claim 7, wherein the step of generating a self-calibration signal based on the OFDM signal and repeatedly transmitting the self-calibration signal within a downlink slot time window comprises:
in the multichannel radio remote unit, each channel transmits different subcarriers in the OFDM signal based on a multicarrier signal of 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 the channels.
9. The method of claim 1, wherein the step of coupling the self-calibration signal to the receive path or the feedback path at the output of the filter after traversing the downlink transmit chain comprises:
in the multi-channel radio remote unit, an on-board combiner is arranged between the output ends of the filters of two adjacent channels for combining.
10. The method of claim 1, wherein the step of collecting the received self-calibration signal in the receive channel or the feedback channel comprises:
and acquiring data of one symbol length in the receiving channel or the feedback channel.
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