CN115580316B - Radio frequency front-end circuit and circuit board for 5G NR-U frequency band - Google Patents
Radio frequency front-end circuit and circuit board for 5G NR-U frequency band Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/26—Modifications of amplifiers to reduce influence of noise generated by amplifying elements
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/32—Modifications of amplifiers to reduce non-linear distortion
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/52—Circuit arrangements for protecting such amplifiers
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/189—High-frequency amplifiers, e.g. radio frequency amplifiers
- H03F3/19—High-frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only
- H03F3/195—High-frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only in integrated circuits
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
- H03F3/213—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only in integrated circuits
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H05K1/18—Printed circuits structurally associated with non-printed electric components
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- H—ELECTRICITY
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- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/294—Indexing scheme relating to amplifiers the amplifier being a low noise amplifier [LNA]
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/451—Indexing scheme relating to amplifiers the amplifier being a radio frequency amplifier
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Abstract
The invention discloses a communication circuit for a 5G NR-U frequency band, which comprises: the system comprises a radio frequency balun, a downlink radio frequency communication module and an uplink radio frequency communication module; the radio frequency balun is used for converting impedance matching between a differential balanced end signal and a single-ended signal output by the receiving radio frequency transceiver to generate an impedance matching signal; the downlink radio frequency communication module is used for carrying out power detection on the impedance matching signal based on the integrated circulator, the first radio frequency switch and the second radio frequency switch and outputting a gain radio frequency modulation signal; and the uplink radio frequency communication module is used for suppressing the received out-of-band signal and amplifying the in-band signal based on the integrated circulator and the second radio frequency switch to generate an amplified signal and sending the amplified signal to the radio frequency balun. The circuit provided by the invention can reduce the cost, is beneficial to the miniaturization of the circuit and meets the communication requirement of a 5G NR-U frequency band.
Description
Technical Field
The invention relates to the technical field of wireless transmission, in particular to a radio frequency front-end circuit and a circuit board for a 5G NR-U frequency band.
Background
Dedicated network devices such as an NR-U base station and a core network are independently deployed in a 5G wireless private network (a professional network which provides safe and reliable wireless services for specific departments or groups, such as government affairs, public safety and other industries), so that the service safety, reliability and specificity of the served groups can be greatly improved. The specific groups particularly belong to the important safety fields, such as transformer substations and intelligent factories, and meet the requirements of mobile and large-bandwidth service applications such as in-station inspection robots, mobile inspection, video monitoring and the like.
However, in the current market, there are few base stations designed based on the 5G NR-U frequency band, most base station radio frequency links adopt discrete devices, the circuit debugging and development cycle is long, the whole machine size is large, the printed board routing line is long, and the discrete radio frequency devices interfere with each other, which causes the radio frequency key indexes (such as stray transmission, low receiving sensitivity, EVM, ACPR, and the like) to be deteriorated.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide a radio frequency front end circuit and a circuit board for a 5G NR-U frequency band, which can reduce cost, facilitate miniaturization of the circuit, and meet communication requirements of the 5G NR-U frequency band.
In order to solve the above technical problem, a first aspect of the present invention discloses a communication circuit for a 5G NR-U band, the communication circuit comprising: the system comprises a radio frequency balun, a downlink radio frequency communication module and an uplink radio frequency communication module; the radio frequency balun is used for converting impedance matching between a differential balanced end signal and a single-ended signal output by the receiving radio frequency transceiver to generate an impedance matching signal; the downlink radio frequency communication module is used for carrying out power detection on the impedance matching signal based on the integrated circulator, the first radio frequency switch and the second radio frequency switch and outputting a gain radio frequency modulation signal; and the uplink radio frequency communication module is used for suppressing the received out-of-band signal and amplifying the in-band signal based on the integrated circulator and the second radio frequency switch to generate an amplified signal and sending the amplified signal to the radio frequency balun.
In some embodiments, the downlink radio frequency communication module includes: the device comprises a signal amplification module, a coupler, a circulator, a first radio frequency switch and a second radio frequency switch; the coupler is used for acquiring the signal processed by the signal amplification module in real time and coupling the signal to generate a coupled signal; a circulator for receiving a standing wave detection signal and a coupling signal for reading the signal state of the antenna, performing power detection, and outputting a gain coupling signal; wherein the circulator is respectively communicated with the first radio frequency switch and the second radio frequency switch.
In some embodiments, wherein the first and second rf switches are both single pole double throw switches; the first end of the first radio frequency switch is connected to the radio frequency balun on the feedback channel of the receiving radio frequency transceiver, the second end of the first radio frequency switch is connected to the coupler, and the third end of the first radio frequency switch is connected to the second radio frequency switch; the first end of the second radio frequency switch is connected to the circulator, and the second end of the second radio frequency switch is connected to the first radio frequency switch; and realizing the closed-loop control of the downlink by the first radio frequency switch and the second radio frequency switch.
In some embodiments, the signal amplification module comprises: the device comprises a push-stage power amplifier, a matcher and a final power amplifier.
In some embodiments, a pre-boost stage power amplifier is further disposed between the boost stage power amplifier and the radio frequency balun.
In some embodiments, the uplink radio frequency communication module includes: the low-noise amplifier, the low-pass filter, the circulator and the second radio frequency switch; the circulator is used for receiving the out-of-band signal input by the antenna and sending the out-of-band signal to the second radio frequency switch; the first end of the second radio frequency switch is connected with the annular device, and the second end of the second radio frequency switch is connected with the low-noise amplifier and used for sending the out-of-band signal to the low-noise amplifier for suppression and amplifying the in-band signal to generate an amplified signal; and the low-pass filter is connected with the low-noise amplifier and used for performing low-pass filtering on the amplified signal and outputting the amplified signal to the radio frequency balun on a feedback channel of the receiving radio frequency transceiver.
In some embodiments, the low noise amplifier is an integrated two-stage low noise amplifier; the low-pass filter is used for carrying out second and third harmonic out-of-band signal suppression and filtering on the amplified signal generated by the integrated two-stage low-noise amplifier and outputting the amplified signal to the radio frequency balun on a feedback channel of the receiving radio frequency transceiver.
In some embodiments, further comprising: and the waveguide filter is used for carrying out transmission stray suppression on the gain coupling signal output by the downlink radio frequency communication module or carrying out-of-band blocking suppression on the out-of-band signal received by the uplink radio frequency communication module.
In some embodiments, the communication circuit for the 5G NR-U band implements signal processing of the downlink radio frequency communication module or the uplink radio frequency communication module in a time division duplex mode.
According to a second aspect of the present invention, there is provided a communication circuit board for a 5G NR-U band, comprising: the device comprises a digital integrated circuit chip, a clock chip, a radio frequency transceiver and the communication circuit for the 5G NR-U frequency band; wherein the radio frequency transceiver is connected with the communication circuit for the 5G NR-U frequency band; the digital integrated circuit chip is respectively connected with the clock chip and the radio frequency transceiver; the communication circuit board for the 5G NR-U frequency band is controlled by the communication circuit for the 5G NR-U frequency band to realize the working frequency band of 5.7GHz-5.9GHz.
Compared with the prior art, the invention has the beneficial effects that:
the invention can realize the communication of the 5G NR-U frequency band through the circuit which is formed by the power amplifier, the first radio frequency switch, the second radio frequency switch, the circulator, the low-noise amplifier, the coupler and the like, has high integration level and is miniaturized, has low total price and saves the size of a PCB. In addition, high-quality output signals are guaranteed through the control of the first radio frequency switch and the second radio frequency switch, and the deterioration of radio frequency key indexes (such as transmission stray, low receiving sensitivity, EVM and ACPR) caused by wiring on a printed board is reduced. And moreover, by adopting the waveguide filter, the signal insertion loss can be controlled below 1dB, the adjacent WiFi frequency band is effectively inhibited, the interference with the WiFi signal is reduced, and the price and the size are also reduced.
Drawings
FIG. 1 is a schematic circuit diagram of a 5G NR-U band communication according to an embodiment of the present invention;
FIG. 2 is a schematic circuit diagram of another embodiment of a communication circuit for a 5G NR-U band;
FIG. 3 is a schematic diagram of an uplink circuit for communication in a 5G NR-U band according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a downlink circuit for communication in a 5G NR-U band according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a communication circuit board for a 5G NR-U band for a specific application according to an embodiment of the present invention;
fig. 6 is a schematic diagram of a time synchronization signal of a communication circuit board for a 5G NR-U band according to a specific application disclosed in an embodiment of the present invention.
Detailed Description
For better understanding and implementation, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. 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 invention.
The terms "comprises," "comprising," and any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or modules is not necessarily limited to those steps or modules explicitly listed, but may include other steps or modules not expressly listed or inherent to such process, method, article, or apparatus.
The embodiment of the invention discloses a communication circuit and a circuit board for a 5G NR-U frequency band, which can realize the communication of the 5G NR-U frequency band through a circuit which is high in integration level and miniaturized and consists of a power amplifier, a first radio frequency switch, a second radio frequency switch, a circulator, a low-noise amplifier, a coupler and the like, and has low total price and PCB size saving. In addition, high-quality output signals are guaranteed through the control of the first radio frequency switch and the second radio frequency switch, and the deterioration of radio frequency key indexes (such as transmission stray, low receiving sensitivity, EVM and ACPR) caused by wiring on a printed board is reduced. And moreover, by adopting the waveguide filter, the signal insertion loss can be controlled below 1dB, the adjacent WiFi frequency band is effectively inhibited, the interference with the WiFi signal is reduced, and the price and the size are also reduced.
Referring to fig. 1, fig. 1 is a schematic diagram of a communication circuit for a 5G NR-U band according to an embodiment of the present invention. The communication circuit for the 5G NR-U band may be applied to a 5G communication system, and the embodiment of the present invention is not limited. As shown in fig. 1, the communication circuit for the 5G NR-U band: the method comprises the following steps: the system comprises a radio frequency balun 1, a downlink radio frequency communication module 2 and an uplink radio frequency communication module 3.
The radio frequency BALUN 1 is also called BALUN, and is configured to convert impedance matching between a differential balanced end signal and a single-ended signal output by a receiving radio frequency transceiver to generate an impedance matching signal, and in an actual signal processing process, impedance matching conversion between a differential balanced end signal (phase difference of 180 °) of 100 ohms or 50 ohms of a receiving radio frequency transceiver trancer and a radio frequency single-ended signal of 50 ohms can be achieved. Then, during the downlink processing, the rf balun 1 sends the impedance matching signal to the downlink rf communication module 2.
And the downlink radio frequency communication module 2 is used for performing power detection on the impedance matching signal based on the integrated circulator, the first radio frequency switch and the second radio frequency switch and outputting a gain radio frequency modulation signal. And the uplink radio frequency communication module 3 is used for suppressing the received out-of-band signal and amplifying the in-band signal based on the integrated circulator and the second radio frequency switch to generate an amplified signal and sending the amplified signal to the radio frequency balun 1.
In other embodiments, as shown in fig. 2, the communication circuit for the 5G NR-U band further includes a waveguide filter 4, configured to perform transmit spur suppression on a gain coupled signal output by the downlink rf communication module or perform out-of-band blocking suppression on an out-of-band signal received by the uplink rf communication module. As the filter of the antenna port is generally used for the transmission spurious suppression and the receiving out-of-band blocking suppression, and is used for improving the out-of-band blocking index of the receiver. At present, most radio frequency circuits adopt a cavity filter and a dielectric filter, the insertion loss of the cavity filter is slightly better than that of the dielectric, but the cavity filter is generally customized, so the price is very high, and the size is large. For a dielectric filter, the optical size is not large, and the insertion loss is large, so that the bit error rate is high. Since the working frequency band in the 5G NR-U system is 5.7-5.9GHz, according to the requirement index, the waveguide filter is adopted in the embodiment, so that the insertion loss can be below 1dB and even reach 0.6dB, and the adjacent WiFi frequency band can be effectively inhibited by 20dB, so that the interference with WiFi signals is reduced, and the system is low in price and small in size.
Specifically, as a preferred embodiment, the downlink rf communication module 2 may be specifically implemented as a structure as shown in fig. 3, and includes a signal amplification module, a coupler, a circulator, a first rf switch, and a second rf switch. Wherein, the signal amplification module includes: the boost power amplifier comprises a push-stage power amplifier, a matcher and a final-stage power amplifier, wherein the matcher is used for realizing impedance (the amount of the current passing blocking capacity of a circuit) matching through resistance, capacitance, inductance or equivalent attributes, namely realizing that vector impedance is changed into radio frequency 50 ohm impedance.
The coupler is used for acquiring the signal processed by the signal amplification module in real time and coupling the signal to generate a coupled signal which can be represented as DPD _ FB. The DPD _ FB is implemented in practical application to acquire an amplified signal output from the final PA in real time through a coupler of 30 dB. The quality of the DPD _ FB signal is the same as that of the final PA, only the signal amplitude is attenuated by 30dB, so that a channel for receiving the DPD _ FB signal is communicated through a second radio frequency switch, the signal can be fed back to a Transceiver, and therefore, the power can be read or a digital predistortion signal is carried out in an FPGA, and the requirements of EVM (error vector amplitude) and ACLR (adjacent channel power ratio) indexes of downlink indexes are met. The line connection implementation of the coupler of the present embodiment is explained in detail: the main function of the coupler is to output at the coupling end according to the size and quality of the direct connection signal, but in the power amplifier and the circulator connected at the left end and the right end of the coupler of the embodiment, the direct connection function of the coupler is utilized in the path between the signal flowing to the power amplifier, the coupler and the circulator, and the coupling function is not adopted here. The signal flow is a circulator, and the path between the couplers utilizes the coupling function of the couplers, namely, the coupling signals are generated, and the coupling signals are generated through electromagnetic field coupling of radio frequency wiring inside the device and do not relate to physical device connection.
The circulator, which receives the standing wave detection signal of the read antenna signal state, can be expressed as VSWR _ FB and the coupling signal for power detection and output of the gain coupling signal. Wherein, the VSWR _ FB is used for reading the antenna signal state, and the antenna matching state (open circuit, short circuit, and loading) can be detected by opening the connection between the VSWR _ FB signal and the second RF switch when the device is processing downlink communication. Because, the output of the transmission signal state detection of the current antenna port is generally a power analog voltage quantity output, namely, the output is performed in a final power amplifier (namely, a final PA shown in the figure) in a signal amplification module of a downlink radio frequency communication module. But for the 5.8G band to which the present invention is directed. WiFi and 5G NR-U have different definitions on ACPR (adjacent channel power ratio of radio frequency signals), and most of WiFi does not need cancellation through external DPD (digital predistortion), so that the ACPR and EVM (error vector magnitude) of the method are different, the error rate of data transmitted at a downlink antenna port is high, interference is caused to equipment in an adjacent frequency band, and the defect of WiFi communication is also caused. Therefore, in this embodiment, a power detection output coupling signal is adopted, so that the downlink radio frequency communication module is integrated into the circuit structure. In practical application, the state of the detected antenna port can be determined based on a required power detection algorithm by detecting the magnitude of the output signal of the receiving end of the circulator and reading the standing wave detection signal of the antenna signal state, and the state of the antenna port can report mismatch (short circuit, open circuit) and matching with load, for example. If the mismatch is detected, an alarm instruction of the standing wave detection signal is sent, the antenna mismatch logic flow is processed, the logic flow is intelligently set according to experience, for example, downlink data output can be closed, the quality of a received link signal is detected, fault location and the like are achieved, and therefore the power amplifier cannot be burnt out due to the mismatch. The line connection implementation of the circulator of the present embodiment is explained in detail: in the actual line connection, the pin connecting the circulator and the coupler is defined as 1 pin, the pin connecting the waveguide filter is defined as 2 pins, and the pin connecting the second rf switch is defined as 3 pins. Mainly explaining the one-way communication function of the circulator in the embodiment, when the 1 pin is communicated with the 2 pin, the signal can only flow from the 1 pin to the 2 pin but not from the 2 pin to the 1 pin, which corresponds to that in a downlink, the coupler can only flow in one way but not return the signal to the waveguide filter, thereby preventing the power amplifier from being burnt out due to excessive signal power. Similarly, the signal can only flow from 2 pins to 3 pins, that is, the signal flow direction is from 1 pin to 2 pins to 3 pins in the downlink, so that the functions of direct connection of the waveguide filter in the band and suppression outside the band can be realized, and the signal after 3 pins is detected can be equivalent to the standing wave state signal of the detection antenna.
Further, the circulator is respectively communicated with the first radio frequency switch and the second radio frequency switch. The first radio frequency switch and the second radio frequency switch are both single-pole double-throw switches. The first end of the first radio frequency switch is connected to the radio frequency balun on the feedback channel of the receiving radio frequency transceiver, the second end of the first radio frequency switch is connected to the coupler, and the third end of the first radio frequency switch is connected to the second radio frequency switch. The first end of the second radio frequency switch is connected to the circulator, and the second end of the second radio frequency switch is connected to the first radio frequency switch; and the first radio frequency switch and the second radio frequency switch are used for realizing the closed-loop control of the downlink.
In other preferred embodiments, a pre-driver stage power amplifier (not shown) is further disposed between the driver stage power amplifier and the rf balun. Therefore, when the circuit of the embodiment is put into practical application, a downstream BBU (baseband processing unit) or front-end card outputs a-14 dBfs signal, the FPGA does not perform any power compensation control, 6dB attenuation is reserved for the radio frequency transceiver Transceiver to be used as frequency compensation and temperature compensation, the gain of the radio frequency front-end circuit is about 32-33dB, and the antenna port can only output 20.5dB at most and has very small margin through calculation. Therefore, a pre-push stage PA is added between the circuit and the connection of the radio frequency transceiver Transceiver, and the PA in the radio frequency integrated chip is adopted with the push stage and the final stage. Thereby, the output power margin can be ensured, and thus, various application scenarios such as coverage can be satisfied.
In the downlink radio frequency communication module, when a Power Amplifier (PA) of a downlink is opened (enabling a pre-driver stage and an integrated radio frequency chip downlink channel), because the PA has nonlinear distortion, a trancer chip detects a signal output by a coupler, the signal is converted into an intermediate frequency signal in a down-conversion mode, the intermediate frequency signal is compared with the intermediate frequency output, digital core cancellation is performed through DPD (digital pre-distortion), the nonlinear distortion of the PA is eliminated, out-of-band suppression is performed through a waveguide filter, the quality of an output signal is ensured, the strength of a feedback power signal is detected at the same time, open-close loop calibration of power is realized, and the radio frequency index deviation can reach a uniform quality index after closed-loop calibration.
In particular, as a preferred embodiment, the structure shown in fig. 4 can be implemented for the uplink radio frequency communication module 3, which includes a low noise amplifier, a low pass filter, a circulator and a second radio frequency switch.
And the circulator is used for receiving the out-of-band signal input by the antenna and sending the out-of-band signal to the second radio frequency switch. The first end of the second radio frequency switch is connected with the annular device, and the second end of the second radio frequency switch is connected with the low-noise amplifier and used for sending the out-of-band signal to the low-noise amplifier for signal amplification processing to generate an amplified signal. The low-pass filter is connected with the low-noise amplifier and used for outputting the amplified signal to the feedback of the receiving radio frequency transceiver after low-pass filtering. A radio frequency balun on the channel.
In a preferred embodiment, the low noise amplifier is an integrated two-stage low noise amplifier, and is specifically realized as an amplifier with a noise figure requirement of 0.5-1 dB. The low-pass filter is used for carrying out second and third harmonic out-of-band signal suppression and filtering on an amplified signal generated by the integrated two-stage low-noise amplifier and outputting the amplified signal to the radio frequency balun on a feedback channel of the receiving radio frequency transceiver.
In the uplink radio frequency communication module, an out-of-band signal enters a waveguide filter through an antenna port, the waveguide filter suppresses the out-of-band signal to improve the out-of-band blocking index of a receiver, and the amplified out-of-band signal is amplified by a Low Noise Amplifier (LNA), input value is subjected to suppression filtering by a low pass filter, and then the suppressed out-of-band signal is output to a radio frequency balun on a feedback channel of a receiving radio frequency transceiver. The gain of the built-in LNA of the uplink can reach 16dB, so that a weak signal can be guaranteed to enter a digital integrated chip FPGA to be sampled, and the weak signal cannot be submerged and cannot be demodulated.
It should be noted that the whole circuit adopts a TDD (time division duplex) mode, LNA amplification enable, standing wave signal, DPD signal, downlink PA enable, etc. can control the integrated radio frequency chip through 1 IO pin, if the discrete device in the prior art is adopted, multiple IO pins are needed to enable control, if board-level interference is large, signals of each control pin arrive asynchronously, which easily causes inconsistency of receiving and transmitting time sequences, data cannot be communicated if light, and a system radio frequency link and a complete machine are short-circuited if heavy. To a certain extent, the reliability is higher, and the environmental suitability is strong.
Referring to fig. 5, fig. 5 is a schematic diagram of a communication circuit board for a 5G NR-U band according to an embodiment of the present invention. The method comprises the following steps: a digital integrated circuit chip FPGA, a clock chip PLL, a radio frequency transceiver Tranceiver chip and a communication circuit for a 5G NR-U frequency band as described in the above embodiments; wherein, the Tranceiver radio frequency transceiver is connected with a communication circuit used for a 5G NR-U frequency band. The digital integrated circuit chip FPGA is respectively connected with the clock chip PLL and the radio frequency transceiver Transceiver; the communication circuit board for the 5G NR-U frequency band is controlled by the communication circuit for the 5G NR-U frequency band, so that the working frequency band is 5.7GHz-5.9GHz. By adopting an integrated structure of a field programmable logic gate array and a Transceiver chip in a digital integrated circuit chip, software programming can be carried out on an FPGA according to an application scene, the WiFi digital signal processing is carried out with enough calculation, a radio frequency part adopts a zero intermediate frequency scheme, and the Transceiver chip supports 650MHz-6000MHz frequency output, namely a system hardware circuit is compatible with a WiFi circuit without any change. The working frequency band of the whole circuit board can be 5.7-5.9GHz of 5G NR-U, the signal bandwidth NR-U is 100MHz and 256QAM is modulated, the total output power of PAR (signal peak-to-average ratio) is not higher than 4W, the integration level of the radio frequency front end is high, the index is more excellent, the cost and the power consumption of the whole circuit board are greatly reduced, and the size of the PCB is reduced.
Further, as shown in fig. 6, in order to synchronize the input and output times of the entire circuit board. Firstly, communication data of BBU or FH is coded and decoded, compressed and decompressed, and data is gathered and distributed through an optical port. And recovering a 156.25M clock signal from the optical port data stream of the downlink BBU or FH, sending the recovered 156.25M clock to a PLL clock chip by the FPGA to be used as a reference clock, locking by taking the reference clock chip as a reference after the clock chip detects the 156.25M reference clock, and outputting a clock signal synchronous with the BBU and FH clocks, thereby ensuring the input and output time synchronization of the whole machine.
The above-described embodiments are only illustrative, and the modules described as separate parts may or may not be physically separate, and the parts displayed as modules may or may not be physical modules, may be located in one place, or may be distributed on a plurality of network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above detailed description of the embodiments, those skilled in the art will clearly understand that each embodiment may be implemented by software plus a necessary general hardware platform, and may also be implemented by hardware. Based on such understanding, the above technical solutions may be embodied in the form of a software product, which may be stored in a computer-readable storage medium, wherein the storage medium includes a Read-Only Memory (ROM), a Random Access Memory (RAM), a Programmable Read-Only Memory (PROM), an Erasable Programmable Read-Only Memory (EPROM), a One-time Programmable Read-Only Memory (OTPROM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a Compact Disc-Read-Only Memory (CD-ROM) or other Memory capable of storing data, a magnetic tape, or any other computer-readable medium capable of storing data.
Finally, it should be noted that: the communication circuit and the circuit board for the 5G NR-U band disclosed in the embodiments of the present invention are only preferred embodiments of the present invention, and are only used for illustrating the technical solutions of the present invention, not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art; the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A communication circuit for a 5G NR-U band, the communication circuit comprising: the system comprises a radio frequency balun, a downlink radio frequency communication module and an uplink radio frequency communication module;
the radio frequency balun is used for converting impedance matching between a differential balanced end signal and a single-ended signal output by the receiving radio frequency transceiver to generate an impedance matching signal;
the downlink radio frequency communication module is used for carrying out power detection on the impedance matching signal based on the integrated circulator, the first radio frequency switch and the second radio frequency switch and outputting a gain radio frequency modulation signal;
and the uplink radio frequency communication module is used for suppressing the received out-of-band signal and amplifying the in-band signal based on the integrated circulator and the second radio frequency switch to generate an amplified signal and sending the amplified signal to the radio frequency balun.
2. The communication circuit for the 5G NR-U band of claim 1, wherein the downlink rf communication module comprises:
the device comprises a signal amplification module, a coupler, a circulator, a first radio frequency switch and a second radio frequency switch;
the coupler is used for acquiring the signal processed by the signal amplification module in real time and coupling the signal to generate a coupled signal;
the circulator is used for receiving the standing wave detection signal and the coupling signal of the antenna signal state for power detection and outputting a gain coupling signal;
wherein the circulator is respectively communicated with the first radio frequency switch and the second radio frequency switch.
3. The communication circuit for 5G NR-U band according to claim 2,
the first radio frequency switch and the second radio frequency switch are both single-pole double-throw switches;
the first end of the first radio frequency switch is connected to the radio frequency balun on the feedback channel of the receiving radio frequency transceiver, the second end of the first radio frequency switch is connected to the coupler, and the third end of the first radio frequency switch is connected to the second radio frequency switch;
the first end of the second radio frequency switch is connected to the circulator, and the second end of the second radio frequency switch is connected to the first radio frequency switch;
and realizing the closed-loop control of the downlink by the first radio frequency switch and the second radio frequency switch.
4. The communication circuit for a 5G NR-U band according to claim 3, wherein the signal amplification module comprises: the device comprises a push-stage power amplifier, a matcher and a final power amplifier.
5. The communication circuit for the 5G NR-U band of claim 4, wherein a pre-driver stage power amplifier is further disposed between the driver stage power amplifier and the radio frequency balun.
6. The communication circuit for 5G NR-U band according to claim 1, wherein the uplink rf communication module comprises:
the low-noise amplifier, the low-pass filter, the circulator and the second radio frequency switch;
the circulator is used for receiving the out-of-band signal input by the antenna and sending the out-of-band signal to the second radio frequency switch;
the first end of the second radio frequency switch is connected with the annular device, and the second end of the second radio frequency switch is connected with the low noise amplifier and used for sending the out-of-band signal to the low noise amplifier for suppression and amplifying the in-band signal to generate an amplified signal;
and the low-pass filter is connected with the low-noise amplifier and used for performing low-pass filtering on the amplified signal and outputting the amplified signal to the radio frequency balun on a feedback channel of the receiving radio frequency transceiver.
7. The communication circuit for 5G NR-U band according to claim 6,
the low-noise amplifier is an integrated two-stage low-noise amplifier;
the low-pass filter is used for carrying out second and third harmonic out-of-band signal suppression and filtering on the amplified signal generated by the integrated two-stage low-noise amplifier and outputting the amplified signal to the radio frequency balun on a feedback channel of the receiving radio frequency transceiver.
8. The communication circuit for a 5G NR-U band according to any one of claims 1 to 7, further comprising:
and the waveguide filter is used for carrying out transmission stray suppression on the gain coupling signal output by the downlink radio frequency communication module or carrying out-of-band blocking suppression on the out-of-band signal received by the uplink radio frequency communication module.
9. The communication circuit for the 5G NR-U band according to claim 8, wherein the communication circuit for the 5G NR-U band implements signal processing of the downlink rf communication module or the uplink rf communication module in a time division duplex mode.
10. A communications circuit board for use in a 5G NR-U band, comprising:
a digital integrated circuit chip, a clock chip, a radio frequency transceiver and a communication circuit for the 5G NR-U band according to any of claims 1 to 9;
wherein the radio frequency transceiver is connected with the communication circuit for the 5G NR-U frequency band;
the digital integrated circuit chip is respectively connected with the clock chip and the radio frequency transceiver;
the communication circuit board for the 5G NR-U frequency band is controlled by the communication circuit for the 5G NR-U frequency band to realize the working frequency band of 5.7GHz-5.9GHz.
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| CN115580316A (en) | 2023-01-06 |
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