WO2021219094A1 - 通信设备和通信系统 - Google Patents

通信设备和通信系统 Download PDF

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Publication number
WO2021219094A1
WO2021219094A1 PCT/CN2021/091109 CN2021091109W WO2021219094A1 WO 2021219094 A1 WO2021219094 A1 WO 2021219094A1 CN 2021091109 W CN2021091109 W CN 2021091109W WO 2021219094 A1 WO2021219094 A1 WO 2021219094A1
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WIPO (PCT)
Prior art keywords
optical
sub
digital
signal
radio frequency
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PCT/CN2021/091109
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English (en)
French (fr)
Inventor
李旭
吕毅博
王天祥
张伟伟
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华为技术有限公司
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Priority to EP21795718.2A priority Critical patent/EP4131802A4/en
Publication of WO2021219094A1 publication Critical patent/WO2021219094A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2575—Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
    • H04B10/25752—Optical arrangements for wireless networks
    • H04B10/25758—Optical arrangements for wireless networks between a central unit and a single remote unit by means of an optical fibre
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2575—Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2575—Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
    • H04B10/25752—Optical arrangements for wireless networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0201—Add-and-drop multiplexing
    • H04J14/0202—Arrangements therefor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects

Definitions

  • the embodiments of the present application relate to communication technologies, and in particular, to a communication device and a communication system.
  • Radio over fiber (RoF) technology is a communication technology that combines optical fiber communication and wireless communication.
  • the RoF system includes a center-side communication device and a remote-side communication device.
  • the center-side communication device is integrated with an electrical-optical signal conversion device
  • the remote-side communication device is integrated with a photoelectric conversion device.
  • the center-side communication device converts the generated baseband signal into a radio frequency signal, and converts the radio frequency signal into an optical signal through an electrical-optical signal conversion device, and then transmits it to the remote-side communication device via an optical fiber.
  • the remote-side communication equipment converts the received optical signal into a radio frequency signal through the photoelectric conversion device, and then transmits the radio frequency signal through the antenna for the user terminal to access and use.
  • the electrical-to-optical signal conversion device is prone to non-linear distortion during the signal conversion process, which in turn results in low quality of the optical signal transmitted to the remote-side communication device.
  • an electrical-optical signal conversion device may also be integrated in the remote-side communication equipment to transmit part of the radio frequency signal through an antenna, and part of the radio frequency signal is converted into an optical signal by the photoelectric signal conversion device and then fed back to Communication equipment on the center side.
  • the center-side communication device converts the feedback optical signal into a baseband signal and compares and analyzes the output baseband signal to determine the distortion of the baseband signal, and then adjust the parameters of the baseband signal to compensate for the nonlinear distortion in the signal conversion process.
  • the non-linear distortion compensation method in the prior art requires the remote-side communication device to feed back the optical signal.
  • the optical signal and the uplink data share the same link.
  • This method requires additional control logic to be set on the central side communication device and the remote side communication device to realize the switching between the uplink data and the feedback optical signal by the central side communication device, and the complexity is high.
  • the embodiments of the present application provide a communication device and a communication system, which can compensate for the nonlinear distortion in the RoF network system, and can also avoid the complicated settings introduced by the remote-side communication device establishing a feedback link.
  • an embodiment of the present application provides a communication device, including: a digital processing device, a first processing device, an optical splitter, a second processing device, and a local oscillator.
  • the first processing device and the digital processing device are respectively The device, the local oscillator, and the optical splitter are connected, the optical splitter is also connected with the second processing device, and the second processing device is also connected with the local oscillator and the digital processing device .
  • the digital processing device is used to generate a first baseband signal, and output the first baseband signal to the first processing device; the first processing device is used to transfer the first baseband signal to the first processing device; A baseband signal is converted into a first radio frequency signal, the first radio frequency signal is converted into an optical signal, and the optical signal is output to the optical splitter; the optical splitter is used to convert the The optical signal is split into a first optical signal and a second optical signal, and the first optical signal is output to at least one remote communication device, and the second optical signal is output to the second processing Device; the second processing device for converting the second optical signal into a second radio frequency signal, and converting the second radio frequency signal into a second baseband signal, and outputting the second baseband signal To the digital processing device; the digital processing device is further configured to perform nonlinear compensation on the first baseband signal according to the first baseband signal and the second baseband signal.
  • the establishment of the feedback link in the central-side communication device in the embodiment of this application can be Under the premise of non-linear distortion compensation, it can also avoid the need to establish a feedback link between the central-side communication device and the remote-side communication device to introduce additional optical fiber and introduce complex control logic, thereby simplifying The settings on the remote side are changed.
  • the digital processing device in the embodiment of the present application includes: a baseband resource pool and a nonlinear compensation device, the baseband resource pool is connected to the nonlinear compensation device, and the The non-linear compensation device is also connected to the first processing device and the second processing device respectively.
  • the baseband resource pool is used to generate the N sub-first baseband signals, and output the N sub-first baseband signals to the first processing device via the nonlinear compensation device;
  • the first The processing device is specifically configured to convert sub-first baseband signals into sub-first radio frequency signals, and the N sub-first radio frequency signals are converted into the optical signals;
  • the second processing device is specifically configured to convert the The second path of optical signals is converted into the N sub-second radio frequency signals, and the sub-second radio frequency signals are converted into the sub-second baseband signals;
  • the nonlinear compensation device is used for The baseband signal and the sub-second baseband signal corresponding to the sub-first baseband signal perform nonlinear compensation on the sub-first baseband signal.
  • the first baseband signal in the embodiment of the present application includes N sub-first baseband signals
  • the second baseband signal includes N sub-second baseband signals
  • the first radio frequency signal includes N sub-first radio signals.
  • the second radio frequency signal includes N sub-second radio frequency signals
  • the sub-first radio frequency signal and the sub-second radio frequency signal correspond one-to-one according to frequency points, and N is an integer greater than or equal to 1.
  • the wavelength of the optical signal in the embodiment of the present application may be 1310 nm. It should be noted that for the optical signal with a wavelength of 1310 nm in the embodiment of the present application, the nonlinear distortion caused by the dispersion of the optical signal in the RoF network system is relatively low and can be ignored. Therefore, the performance of the RoF network system can be improved as a whole by performing local compensation for the non-linearity of the devices in the center-side communication device in the embodiment of the present application. However, it should be noted that the technical solutions in the embodiments of the present application can also be applied to optical fiber communication systems corresponding to optical signals with a wavelength of 1550 nm, and other optical fiber communication systems of different wavelengths.
  • N is equal to 1 and N is greater than 1
  • the structure settings of the first processing device and the second processing device in the communication device in the embodiment of the present application are different. Therefore, the following describes the structure of the communication device from two aspects: equal to 1 and when N is greater than 1.
  • the structure of the communication device provided in the embodiment of the present application is suitable for the compensation of the nonlinear distortion of a signal of a single wavelength and a single frequency point.
  • the first processing device may include: a digital-to-analog conversion device, a first mixer, a band-pass filter, and an electro-optical conversion device;
  • the second processing device may include: a photoelectric conversion device, a second mixer Frequency converter, low-pass filter and analog-to-digital conversion device.
  • the digital-to-analog conversion device is respectively connected with the nonlinear compensation device and the first mixer, the band-pass filter is respectively connected with the first mixer and the electro-optical conversion device, the first mixer is also connected with the local oscillator, and the electro-optical conversion
  • the device is also connected with the optical splitter; the second mixer is respectively connected with the photoelectric conversion device, the low-pass filter, and the local oscillator, and the analog-to-digital conversion device is connected with the low-pass filter and the nonlinear compensation device.
  • the first processing device may further include: an adjustable attenuator and a low-noise amplifier.
  • the adjustable attenuator is respectively connected with the band-pass filter and the low-noise amplifier
  • the low-noise amplifier is also connected with the electro-optical conversion device.
  • the first processing device may further include: an optical domain amplifier, which is respectively connected to the electro-optical conversion device and the optical splitter. Optical domain amplifier, used to amplify the power of optical signals.
  • the second processing device may further include: an electrical domain amplifier, which is respectively connected to a low-pass filter and an analog-to-digital conversion device. The electrical domain amplifier is used to amplify the power of the second radio frequency signal.
  • the second processing device may further include: an electrical domain amplifier, which is respectively connected to the digital-to-analog conversion device and the low-pass filter.
  • the third processing device in the remote-side communication device may include: a photoelectric conversion device.
  • the photoelectric conversion device is connected to the optical splitter through an optical fiber, and the photoelectric conversion device is used to convert the first optical signal into a radio frequency signal and output it to the antenna.
  • the antenna can output radio frequency signals.
  • the electro-optical conversion device in the embodiment of the present application may be EML or DML.
  • the following describes the compensation method of the nonlinear compensation device when the electro-optical conversion device is EML or DML. It should be understood that the nonlinear compensation device in this embodiment Including: digital predistortion module and parameter estimation module.
  • the first method the electro-optical conversion device is an external modulator or a direct modulator.
  • the digital predistortion module is configured to perform predistortion processing on the first baseband signal by using distortion parameters.
  • the parameter estimation module is configured to update the distortion parameter according to the first baseband signal and the second baseband signal, so as to perform nonlinear compensation on the first baseband signal.
  • the nonlinear compensation method adopted in the first method is a one-dimensional DPD nonlinear compensation method.
  • the one-dimensional DPD nonlinear compensation method is to use a one-dimensional DPD model for nonlinear compensation, and the one-dimensional DPD model is not limited to a polynomial model and a neural network model.
  • the second way: the electro-optical conversion device is an external modulator.
  • the digital predistortion module is configured to perform predistortion processing on the first baseband signal by using distortion parameters;
  • the parameter estimation module is configured to obtain Preset the difference between the bias voltage and the half-wave voltage of the external modulator; according to the difference, update the distortion parameter to perform nonlinear compensation on the first baseband signal.
  • the nonlinear compensation method adopted in the first method is a method in which the difference between the half-wave voltage of the external modulator EML and the preset bias voltage is compensated.
  • the following first describes the structure of the communication device from two possible implementation modes.
  • the structure of the communication device in the two possible implementation modes is suitable for the nonlinearity of the signal of single wavelength and multiple frequency points. Compensation for distortion.
  • the communication device further includes an electric domain combiner and an electric domain splitter, the electric domain combiner is connected to the first processing device, and the electric domain splitter is connected to The second processing device is connected.
  • the first processing device is specifically configured to convert the first sub-baseband signal into a sub-first radio frequency signal, and output the sub-first radio frequency signal to the electrical domain combiner;
  • the domain combiner is used to combine N sub-first radio frequency signals, and output the combined radio frequency signals to the first processing device;
  • the first processing device is specifically also used to combine the The radio frequency signal is converted into the optical signal.
  • the second processing device is specifically configured to convert the second optical signal into a second radio frequency signal and output it to the electrical domain splitter; the electrical domain splitter is used to convert the second radio frequency signal
  • the two radio frequency signals are split into N sub-second radio frequency signals, and the N sub-second radio frequency signals are output to the second processing device; the second processing device is specifically also used to convert the sub-second radio frequency signals into all Said sub-second baseband signals to obtain said N sub-second baseband signals.
  • the first processing module includes an electro-optical conversion device and N digital-to-analog conversion devices
  • the second processing device includes: a photoelectric conversion device and N analog-to-digital conversion devices, the number of local oscillators is N, and One local oscillator corresponds to one digital-to-analog conversion device and one analog-to-digital conversion device.
  • the electric domain combiner is respectively connected to the N digital-to-analog conversion devices and the electro-optical conversion device, the N digital-to-analog conversion devices are also connected to the nonlinear compensation device, and each local oscillator is connected to the corresponding The digital-to-analog conversion device and the analog-to-digital conversion device are connected to each other, the optical splitter is connected to the electro-optical conversion device and the photoelectric conversion device respectively, and the electrical domain splitter is connected to the photoelectric conversion device and the N The N analog-to-digital conversion devices are all connected to the non-linear compensation device.
  • the first processing module further includes: N first mixers, N band pass filters, and one digital-to-analog conversion device corresponds to one first mixer, One band-pass filter, one local oscillator; the second processing device further includes: N second mixers and N low-pass filters, one analog-to-digital conversion device corresponds to one second mixer, one low-pass Filter, a local oscillator.
  • the first processing device further includes: N adjustable attenuators, N low-noise amplifiers, and one band-pass filter corresponds to one adjustable attenuator and one low-noise amplifier.
  • the first processing device further includes: an optical domain amplifier.
  • the second processing device further includes: an electrical domain amplifier. It should be understood that the connection mode of the device in this mode can refer to the fourth embodiment below.
  • the communication device includes an electric domain combiner and N electric domain switches.
  • the electric domain splitter is connected to the second processing device, the electric domain switch is connected to the local oscillator and the second processing device respectively, and one electric domain switch corresponds to one sub-first radio frequency signal.
  • the second processing device is specifically configured to convert the second optical signal into a second radio frequency signal; an electrical domain switch is used to control the communication of the feedback link of the second radio frequency signal corresponding to the first radio frequency signal. Off;
  • the second processing device is specifically also used to convert the feedback sub-second radio frequency signal into a sub-second baseband signal. In this manner, by controlling the electrical domain switch, it is possible to realize the feedback of the sub-second baseband signal of a specific frequency point, and then perform nonlinear compensation on the signal of the frequency point.
  • the first processing module includes an electro-optical conversion device and N digital-to-analog conversion devices
  • the second processing device includes: a photoelectric conversion device and an analog-to-digital conversion device, the number of local oscillators is N, and One local oscillator corresponds to one digital-to-analog conversion device and one electric domain switch; the electric domain combiner is respectively connected to the N digital-to-analog conversion devices and the electro-optical conversion device, and the N digital-to-analog conversion devices are also connected to
  • the nonlinear compensation device is connected, each local oscillator is connected to a corresponding digital-to-analog conversion device and an electrical domain switch, the optical splitter is connected to the electro-optical conversion device and the photoelectric conversion device, respectively, and the analog-to-digital The conversion device is respectively connected with the photoelectric conversion device, the N electrical domain switches, and the nonlinear compensation device.
  • the first processing module further includes: N first mixers, N band pass filters, and one digital-to-analog conversion device corresponds to one first mixer, A band-pass filter and a local oscillator; the second processing device further includes: a second mixer and a low-pass filter.
  • the first processing device further includes: N adjustable attenuators, N low-noise amplifiers, and one band-pass filter corresponds to one adjustable attenuator and one low-noise amplifier.
  • the first processing device further includes: an optical domain amplifier.
  • the second processing device further includes: an electrical domain amplifier. It should be understood that the connection mode of the device in this mode can refer to the fifth embodiment below.
  • the structure of the communication device in the above two possible implementations is suitable for the compensation of the nonlinear distortion of the single-wavelength multi-frequency signal, and the communication in the two possible implementations is provided below.
  • the structure of the device is suitable for the compensation of nonlinear distortion of multi-wavelength and multi-frequency signals.
  • the communication device further includes a wavelength division multiplexer and a wavelength division multiplexer, and the wavelength division multiplexer is respectively connected to the first processing device and the optical splitter , The wavelength division multiplexer is respectively connected with the optical splitter and the second processing device.
  • the first processing device is specifically configured to convert the sub-first baseband signal into a sub-first radio frequency signal, and convert the sub-first radio frequency signal into a sub-first optical signal, so as to obtain N sub-first optical signals.
  • An optical signal the optical signal includes the N sub-first optical signals; the wavelength division multiplexer is used to combine the N sub-first optical signals, and output the combined optical signal to all The optical splitter; the wavelength division multiplexer is used to split the second optical signal into N sub-second optical signals; the second processing device is specifically used to divide the sub-second optical signal
  • the optical signal is converted into a sub-second radio frequency signal, and the sub-second radio frequency signal is converted into the sub-second baseband signal to obtain N sub-second baseband signals.
  • the first processing module includes N digital-to-analog conversion devices, N electro-optical conversion devices, one digital-to-analog conversion device corresponds to one electro-optical conversion device
  • the second processing device includes: N photoelectric conversion devices Compared with N analog-to-digital conversion devices, one photoelectric conversion device corresponds to one analog-to-digital conversion device, the number of local oscillators is N, and one local oscillator corresponds to one digital-to-analog conversion device and one analog-to-digital conversion device; wherein, the nonlinear compensation The device is connected to the N digital-to-analog conversion devices, each digital-to-analog conversion device is connected to a corresponding electro-optical conversion device and a local oscillator, and the wavelength division multiplexer is respectively connected to the N electro-optical conversion devices and the optical division The wavelength division multiplexer is connected to the N photoelectric conversion devices and the optical splitter respectively, and each analog-to-digital conversion device is also connected to a corresponding photoelectric conversion device
  • the first processing module further includes: N first mixers and N bandpass filters; and the second processing device further includes: N second mixers. Mixer and N low-pass filters.
  • the first processing device further includes: N adjustable attenuators and N low noise amplifiers.
  • the first processing device further includes: an optical domain amplifier.
  • the second processing device further includes: an electrical domain amplifier. It should be understood that the connection mode of the device in this mode can refer to the sixth embodiment below.
  • the communication device further includes a wavelength division multiplexer and a wavelength division multiplexer, and the connection mode and function of the wavelength division multiplexer and the wavelength division multiplexer can refer to the above possible implementation manners.
  • the communication device in this manner further includes: 2N electrical domain switches.
  • the local oscillator is connected to N electric domain switches, and the N electric domain switches are also connected to a second processing device.
  • One electric domain switch corresponds to one sub-first radio frequency signal
  • the second processing device also Connected to the remaining N electrical domain switches
  • one electrical domain switch corresponds to one sub-second radio frequency signal
  • one sub-first radio frequency signal corresponds to one sub-second radio frequency signal.
  • the electrical domain switch is used to control the on/off of the feedback link of the sub-second radio frequency signal corresponding to the sub-first radio frequency signal; the second processing device is specifically also used to convert the feedback sub-second radio frequency signal into a sub-second radio frequency signal. Two baseband signals. In this manner, by controlling the electrical domain switch, it is possible to realize the feedback of the sub-second baseband signal of a specific frequency point, and then perform nonlinear compensation on the signal of the frequency point.
  • the first processing module includes N digital-to-analog conversion devices, N electro-optical conversion devices, one digital-to-analog conversion device corresponds to one electro-optical conversion device
  • the second processing device includes: N photoelectric conversion devices As with the analog-to-digital conversion device, one photoelectric conversion device corresponds to one electric domain switch, the number of local oscillators is N, and one local oscillator corresponds to one digital-to-analog conversion device, one electric domain switch, and one analog-to-digital conversion device.
  • the nonlinear compensation device is connected to the N digital-to-analog conversion devices, each digital-to-analog conversion device is connected to a corresponding electro-optical conversion device and a local oscillator, and each local oscillator is also connected to a corresponding electric domain switch, so
  • the wavelength division multiplexer is respectively connected to the N electro-optical conversion devices and the optical splitter, and the wavelength division multiplexer is respectively connected to the N photoelectric conversion devices and the optical splitter, and each photoelectric conversion device is connected to the optical splitter.
  • the conversion device is connected to a corresponding electrical domain switch, the 2N electrical domain switches are all connected to the analog-to-digital conversion device, and the analog-to-digital conversion device is also connected to the nonlinear compensation device.
  • the first processing module further includes: N first mixers and N bandpass filters; and the second processing device further includes: second mixers. And low-pass filter.
  • the first processing device further includes: N adjustable attenuators and N low noise amplifiers.
  • the first processing device further includes: an optical domain amplifier.
  • the second processing device further includes: an electrical domain amplifier.
  • the non-linear compensation device in the example includes: a digital predistortion module and a parameter estimation module.
  • the first method the electro-optical conversion device is an external modulator or a direct modulator.
  • the digital predistortion module is configured to perform predistortion processing on the sub-first baseband signal by using distortion parameters.
  • the parameter estimation module is configured to update the distortion parameter according to the sub-first baseband signal and the sub-second baseband signal to perform nonlinear compensation on the sub-first baseband signal.
  • the nonlinear compensation method adopted in the first method is a multi-dimensional DPD nonlinear compensation method.
  • the multi-dimensional DPD model is not limited to a polynomial model and a neural network model.
  • the use of a multi-dimensional DPD model for compensation can not only compensate for the nonlinear distortion of a single-channel baseband signal in the transmission process, but also compensate for the nonlinear distortion caused by the intermodulation and crosstalk between the multi-channel baseband signals.
  • the second way: the electro-optical conversion device is an external modulator.
  • the digital predistortion module is used to perform predistortion processing on the sub-first baseband signal using distortion parameters; the parameter estimation module is used to obtain the preset offset according to the sub-first baseband signal and the sub-second baseband signal The difference between the voltage and the half-wave voltage of the external modulator; according to the difference, the distortion parameter is updated to perform nonlinear compensation on the sub-first baseband signal.
  • the manner of performing nonlinear compensation on the sub-first baseband signal may refer to the related description of performing nonlinear compensation on the first baseband signal in the foregoing manner.
  • an embodiment of the present application provides a communication system, including the communication device described in the first aspect and a remote-side communication device, wherein the communication device in the first aspect is a remote communication system Communication equipment on the center side.
  • the remote-side communication device is used to convert the first optical signal from the central-side communication device into a radio frequency signal, and transmit the radio frequency signal through an antenna.
  • the embodiment of the application provides a communication device and a communication system.
  • the communication device is a central-side communication device.
  • a feedback link is established in the central-side communication device, and the feedback link is used for feedback via the central-side communication device.
  • the baseband signal with nonlinear distortion processed by the device in the center side communication device can compensate the nonlinear distortion of the baseband signal according to the generated baseband signal and the signal fed back by the feedback link to improve the signal transmission quality. Because the nonlinear distortion in the RoF network system mainly occurs in the center-side communication device, the structure of the center-side communication device in the embodiment of the present application can compensate for the nonlinear distortion in the RoF network system. It can also avoid the need to establish a feedback link between the central-side communication device and the remote-side communication device to introduce additional optical fiber and introduce complicated control logic, thereby simplifying the configuration of the remote side.
  • FIG. 1 is a schematic structural diagram of a remote network system that transmits signals through a coaxial cable in the prior art
  • FIG. 2 is a schematic diagram of the structure of a CPRI network system in the prior art
  • Figure 3 is a schematic diagram of the structure of an optical radio network system in the prior art
  • FIG. 4 is a structural schematic diagram 1 of an electro-optical conversion device in a RoF network system provided in the prior art
  • Fig. 5 is a schematic diagram 2 of the structure of the electro-optical conversion device in the RoF network system provided in the prior art
  • FIG. 6 is the third structural diagram of the electro-optical conversion device in the RoF network system provided in the prior art.
  • Fig. 7 is a schematic structural diagram of a RoF network system provided in the prior art.
  • FIG. 8 is a schematic diagram of the architecture of the RoF network system provided by an embodiment of the application.
  • FIG. 9 is a schematic structural diagram of a RoF network system according to an embodiment provided by an embodiment of this application.
  • FIG. 10 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • FIG. 11 is a schematic diagram of one-dimensional DPD nonlinear compensation provided by an embodiment of the application.
  • FIG. 12 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • FIG. 13 is a schematic diagram of nonlinear compensation of EML provided by an embodiment of the application.
  • FIG. 14 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • FIG. 15 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • 16 is a schematic diagram of multi-dimensional DPD nonlinear compensation provided by an embodiment of the application.
  • FIG. 17 is a schematic diagram of performance of intermodulation and crosstalk between multi-frequency baseband signals provided by an embodiment of the application.
  • FIG. 18 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • FIG. 19 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • FIG. 20 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • FIG. 21 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • FIG. 22 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • FIG. 23 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • the remote network system is composed of a central side communication device and at least one remote side communication device.
  • the central side communication device generates a baseband signal
  • the remote side communication device converts the baseband signal into a radio frequency signal for user terminal access. .
  • Fig. 1 is a schematic structural diagram of a remote network system that transmits signals through a coaxial cable in the prior art.
  • the central side communication device 10 and the remote side communication device are connected by a coaxial cable.
  • the central side communication device 10 includes a baseband signal processing unit (DU) and a radio frequency signal processing unit (RU).
  • the remote side communication device 20 includes a radio frequency signal transmission unit.
  • the radio frequency signal transmission unit such as a radio head, RH).
  • the central side communication device 10 generates a baseband signal, converts the baseband signal into a radio frequency signal through the DU and RU, and then transmits the radio frequency signal to the remote side communication device 20 through a coaxial cable.
  • the remote side communication device 20 can transmit the received radio frequency signal through the RH.
  • the radio frequency signal is transmitted through the coaxial cable, and the transmission rate is low.
  • FIG. 2 is a schematic diagram of the structure of a CPRI network system in the prior art.
  • the center-side communication device 10 and the remote The side communication devices 20 are connected by optical fibers, the center side communication device 10 includes DU, and the remote side communication device 20 includes RU and RH.
  • the center-side communication device 10 After the center-side communication device 10 generates a baseband signal, it transmits the baseband signal to the remote-side communication device 20 through an optical fiber.
  • the remote side communication device 20 can convert the baseband signal into a radio frequency signal through the RU, and transmit the radio frequency signal through the RH.
  • CPRI and eCPRI network systems use optical fiber to transmit baseband signals, the transmission rate of signals is faster than that of coaxial cables, but compared to the optical carrier radio network system in Figure 3 below, the signal transmission rate is Still low.
  • FIG. 3 is a schematic diagram of the structure of an optical radio network system in the prior art.
  • the central-side communication device 10 includes DU, RU, and an electrical-optical signal conversion device
  • the remote-side communication device 20 includes a photoelectric conversion device.
  • the center-side communication device converts the generated baseband signal into a radio frequency signal, and converts the radio frequency signal into an optical signal through an electrical-optical signal conversion device, and then transmits it to the remote-side communication device via an optical fiber.
  • the remote-side communication equipment converts the received optical signal into a radio frequency signal through the photoelectric conversion device, and then transmits the radio frequency signal through the RH.
  • the RoF network system simplifies the setup of the communication equipment on the remote side.
  • Multiple devices such as DU, RU, and electro-optical signal conversion device are installed in the communication equipment on the central side, which can effectively reduce the cost of the communication equipment on the remote side and facilitate rapid layout.
  • Communication equipment on the remote side to improve network coverage. Because in the RoF network system, it is necessary to convert the radio frequency signal into an optical signal through the electro-optical conversion device, and the electro-optical conversion device is prone to non-linear distortion in the signal conversion process, and the optical signal will also cause the optical signal due to the dispersion during the transmission process. The non-linear distortion of the signal in turn causes the non-linear distortion of the optical signal transmitted in the RoF network system, resulting in low quality of the optical signal.
  • Fig. 4 is a first structural diagram of an electro-optical conversion device in a RoF network system provided in the prior art.
  • the electro-optical conversion device in the RoF network system structure is an external modulation laser (EML), and the EML may include a bias voltage adjustment unit and a dispersion compensation unit.
  • EML external modulation laser
  • the non-linear distortion generated by the electro-optical conversion device during the signal conversion process can cause the change of the bias voltage of the electro-optical conversion device. Therefore, in FIG. 4, the bias voltage of the electro-optical conversion device can be adjusted by the bias voltage adjustment unit.
  • the non-linear distortion generated by the electro-optical conversion device in the signal conversion process is eliminated.
  • the dispersion compensation unit can also perform nonlinear compensation on the nonlinear distortion caused by the dispersion of the optical signal, so as to eliminate the nonlinear distortion caused by the transmission of the optical signal.
  • the compensation method in FIG. 4 only considers nonlinear compensation when the electro-optical conversion device is an EML.
  • This compensation method is not suitable for scenarios where the electro-optical conversion device is a direct modulator laser (DML), and has limited applicability.
  • the compensation effect of the dispersion compensation unit in this compensation method for nonlinear distortion is related to the wavelength of the optical signal and the length of the optical fiber, and the compensation effect is poor in robustness and high in cost.
  • this compensation method does not consider the nonlinear distortion caused by the memory characteristics of the EML.
  • the memory characteristic is the characteristic that the signal transmitted at the previous moment in the signal transmission process has an influence on the subsequent transmitted signal, and this characteristic is an inherent characteristic related to the device.
  • Non-linear distortion may include low-order non-linear distortion and high-order non-linear distortion. Among them, high-order nonlinear distortion has a greater impact on the quality of the optical signal. Therefore, based on the above-mentioned Figure 4, in order to further improve the effect of the compensation of negative nonlinear distortion, Figure 5 provides a method for high-order nonlinear distortion. Distortion compensation method.
  • FIG. 5 is the second structural diagram of the electro-optical conversion device in the RoF network system provided in the prior art. As shown in FIG.
  • the electro-optical conversion device in the RoF network system structure is an external modulator EML
  • the EML may include a high-order nonlinear distortion compensation unit
  • the high-order nonlinear distortion compensation unit includes a bias voltage adjustment unit and Dispersion compensation unit.
  • the dispersion compensation unit compensates for the second-order nonlinear distortion
  • the bias voltage adjustment unit compensates for the third-order or higher-order nonlinear distortion, so the nonlinear compensation method in Figure 5
  • the compensation effect is more significant.
  • the method in FIG. 5 still has the same problem as that in FIG. 4 above.
  • FIG. 6 provides a method of digital pre-distortion (DPD) nonlinear compensation based on memory polynomials.
  • DPD digital pre-distortion
  • FIG. 6 is the third structural diagram of the electro-optical conversion device in the RoF network system provided in the prior art.
  • the electro-optical conversion device in the RoF network system structure may be EML or DML
  • the electro-optical conversion device includes a DPD compensation unit, and the DPD compensation unit outputs a signal from the electro-optical conversion device according to the input signal of the electro-optical conversion device and the output signal from the electro-optical conversion device.
  • the nonlinear compensation method of DPD can be applied to EML or DML, and the nonlinear distortion caused by the memory characteristic of the electro-optical conversion device is also considered, the effect of nonlinear compensation can be improved.
  • the nonlinear compensation method in Figure 6 is only applicable to electro-optical conversion devices, and does not take into account the nonlinear distortion caused by other components commonly included in the RoF network system, such as power amplifier (PA), etc., so the RoF network system There will also be nonlinear distortions.
  • PA power amplifier
  • the non-linear compensation method of DPD can refer to the related description of the non-linear compensation method of DPD in the following embodiments of the present application.
  • FIG. 7 provides a method for non-linear compensation of digital pre-distortion (DPD) based on a memory polynomial.
  • DPD digital pre-distortion
  • FIG. 7 is a schematic structural diagram of a RoF network system provided in the prior art.
  • the RoF network system also includes a center-side communication device 10 and a remote-side communication device 20.
  • the device settings in the center-side communication device 10 and the remote-side communication device 20 please refer to the above image 3.
  • the remote-side communication device 20 in FIG. 7 also includes a radio frequency signal splitting device, and the RoF network system also includes a feedback link.
  • the radio frequency signal splitting device transmits part of the radio frequency signal from the photoelectric signal conversion device, and outputs the other part of the radio frequency signal to the feedback link.
  • the remote-side communication equipment 20 includes an electro-optical conversion device, another part of the radio frequency signal is converted into an optical signal by the photoelectric signal conversion device and then fed back to the central-side communication equipment, and the central-side communication equipment 10 converts the feedback optical signal After the baseband signal is compared and analyzed with the output baseband signal, the nonlinear distortion of the baseband signal is determined, and then the parameters of the baseband signal are adjusted to compensate for the nonlinear distortion in the signal conversion process.
  • the method shown in Figure 7 can compensate for the non-linear distortion caused by the setting of other devices in the RoF network system, the method in Figure 7 requires the remote side communication equipment to feed back the optical signal, so the central side communication equipment is required An additional optical fiber is needed between the communication device on the remote side to establish a feedback link.
  • the optical signal and the uplink data can share the same link (as shown in Figure 7 for connecting the electrical-optical signal conversion device and the photoelectric signal conversion device) Optical fiber), but this method requires additional control logic to be set on the central-side communication device and the remote-side communication device to realize the switching between the uplink data and the feedback optical signal by the central-side communication device, which has high complexity.
  • the existing RoF network system simplifies the configuration of the remote-side communication equipment.
  • the central-side communication equipment integrates multiple devices such as DU, RU, and electrical-to-optical signal conversion devices. Therefore, the nonlinear distortion in the RoF network system mainly occurs in the center. In the side communication equipment. Therefore, in order to solve the above technical problems, in the embodiment of the present application, by establishing a feedback link in the central side communication device, on the premise that the nonlinear distortion in the RoF network system can be compensated, the need to communicate on the central side can also be avoided.
  • the establishment of a feedback link between the device and the remote-side communication device introduces additional fiber optics, and introduces complicated control logic, and can simplify the settings on the remote side.
  • FIG. 8 is a schematic diagram of the RoF network system architecture provided by an embodiment of the application.
  • the RoF network system includes a center-side communication device 10 and a plurality of remote-side communication devices 20.
  • the central side communication device 10 and the multiple remote side communication devices 20 are connected by optical fibers, where the optical fiber between the two may be 5-50 km.
  • the center-side communication device in FIG. 8 includes at least one analog baseband processing unit (BBU), and each remote-side communication device includes a radio remote unit (RRU).
  • BBU analog baseband processing unit
  • RRU radio remote unit
  • the RoF network system in the embodiment of this application is suitable for macro sites (urban area), small sites, such as millimeter-wave small cell (mmWave small cell), hot spot area (hor-spot area) and other scenarios.
  • the remote side communication device may be a base station, which may be a base station (Base Transceiver Station, referred to as BTS) in a GSM system or a CDMA system, or a base station (NodeB, referred to as NB) in a WCDMA system, or The evolved NodeB (eNB for short) and the next-generation base stations (collectively referred to as the NG-RAN node) in the LTE system.
  • the next-generation base station includes a new radio node (NR nodeB, gNB). ), a new generation evolved base station (NG-eNB), which is not limited here.
  • FIG. 9 is a schematic structural diagram of a RoF network system according to an embodiment provided by an embodiment of this application.
  • the RoF network system in the embodiment of the present application includes a center-side communication device 10 and at least one remote-side communication device. It should be understood that FIG. 9 schematically takes a remote-side communication device as an example for illustration. .
  • the center-side communication device 10 includes: a digital processing device 11, a first processing device 12, an optical splitter 13, a second processing device 14 and a local oscillator 15.
  • the first processing device 12 is connected to the digital processing device 11, the local oscillator 15, and the optical splitter 13, the optical splitter 13 is also connected to the second processing device 14, and the second processing device 14 is also connected to the local oscillator 15, The digital processing device 11 is connected.
  • the digital processing device 11 is used to generate a first baseband signal and output the first baseband signal to the first processing device 12.
  • the digital processing device 11 in the embodiment of the present application may generate a source of a baseband signal, such as a baseband resource pool.
  • the first processing device 12 is configured to convert the first baseband signal to the first radio frequency signal, convert the first radio frequency signal into an optical signal, and output the optical signal to the optical splitter 13.
  • the local oscillator 15 in the embodiment of the present application is used to generate a radio frequency signal.
  • the first baseband signal in the embodiment of the present application may be a digital baseband signal.
  • the first processing device 12 may convert the first baseband signal into a first radio frequency signal through the local oscillator 15, and convert the first radio frequency signal into an optical signal.
  • the first processing device 12 can convert the first baseband signal into a first radio frequency signal with a specific frequency through the local oscillator 15.
  • the optical splitter 13 After the optical splitter 13 receives the optical signal from the first processing device 12, the optical splitter 13 is used to split the optical signal into a first optical signal and a second optical signal, and divide the first optical signal The optical signal is output to at least one remote communication device, and the second optical signal is output to the second processing device 14.
  • the wavelengths of the first optical signal and the second optical signal in the embodiment of the present application are the same, but the power is different.
  • a power ratio of 9:1 is used to split the optical signal into the first optical signal and the second optical signal, where the power of the first optical signal accounts for 90%, and the second optical signal has a power ratio of 90%.
  • the power of the optical signal accounts for 10%.
  • the central side communication device 10 converts the digital baseband signal into an analog baseband signal, and transmits the analog baseband signal to the remote side communication device via optical fiber 20.
  • the analog baseband signal is transmitted on the optical fiber.
  • the central side communication device 10 in the embodiment of the present application can convert a digital baseband signal into a radio frequency signal, then convert the radio frequency signal into an optical signal, and transmit the optical signal to the remote side communication device 20 through an optical fiber.
  • the center-side communication device 10 can transmit radio frequency signals, while the center-side communication device 10 in the prior art transmits baseband signals, because the baseband signal is a signal with a center frequency of 0 Hz, and the radio frequency signal But it can correspond to different frequency points. Therefore, the network system in the embodiment of the present application can transmit signals of multiple frequency points, while the CPRI/eCPRI network system can transmit signals of one frequency point as much as possible.
  • the frequency points of the signals of each different communication standard are different.
  • the communication standard may be a long-term evolution (LTE) communication standard, a universal mobile telecommunications system (UMTS) communication standard, a wireless broadband (wireless-fidelity, WIFI) communication standard, millimeter wave and other communication standards. Therefore, the network system in the embodiment of the present application can be applied to a scenario where multiple communication standards coexist, while the CPRI/eCPRI network system is only applicable to a scenario where one communication standard exists.
  • the remote communication device 20 may include a third processing device 21 and an antenna 22.
  • the third processing device 21 can convert the first optical signal into a radio frequency signal, and output it to the antenna 22, and the antenna 22 transmits the radio frequency signal for the user to access and use.
  • the second processing device 14 is used for converting the second optical signal into a second radio frequency signal, and converting the second radio frequency signal into a second baseband signal, and outputting the second baseband signal to the digital processing ⁇ 11 ⁇ Device 11.
  • the second baseband signal is a digital baseband signal.
  • the second processing device 14 may convert the optical signal into an electrical domain signal, and then convert the electrical domain signal into a second radio frequency signal through the local oscillator 15, and convert the second radio frequency signal into a second baseband signal. It should be understood that the frequency point of the second radio frequency signal in the embodiment of the present application is the same as the frequency point of the first radio frequency signal.
  • the digital processing device 11 is also used to perform nonlinear compensation on the first baseband signal according to the first baseband signal and the second baseband signal.
  • the digital processing device 11 can output the first baseband signal, and can also receive the second baseband signal processed by each device. Therefore, the first baseband signal and the second baseband signal can be compared and analyzed to determine the first baseband signal.
  • the baseband signal performs nonlinear compensation to eliminate the nonlinear distortion of the first baseband signal, thereby improving the quality of the first baseband signal, and correspondingly, improving the quality of the signal transmitted in the RoF network system.
  • the digital processing device 11 in this embodiment may include a baseband resource pool 111 and a nonlinear compensation device 112.
  • the baseband resource pool 111 is connected to the non-linear compensation device 112
  • the non-linear compensation device 112 is also connected to the first processing device 12 and the second processing device 14 respectively.
  • the arrow in FIG. 9 can represent the direction of signal transmission, and can also represent the connection in the center-side communication device 10. The definition of the arrow in the following figure is the same as that of FIG. 9.
  • the first baseband signal in the embodiment of the present application includes N sub-first baseband signals
  • the second baseband signal includes N sub-second baseband signals
  • the first radio frequency signal includes N sub-first radio frequency signals
  • the second radio frequency signal includes N sub-first baseband signals.
  • the signal includes N sub-second radio frequency signals
  • the sub-first radio frequency signal and the sub-second radio frequency signal correspond one-to-one according to frequency points, and N is an integer greater than or equal to 1.
  • the baseband resource pool 111 is used to generate the above N sub-first baseband signals, and output the N sub-first baseband signals to the first processing device 12 via the nonlinear compensation device 112.
  • the first processing device is specifically configured to convert the sub-first baseband signals into sub-first radio frequency signals, and convert the N sub-first radio frequency signals into optical signals.
  • the second processing device is specifically configured to convert the second optical signal into N sub-second radio frequency signals, and convert the sub-second radio frequency signals into sub-second baseband signals.
  • the N sub-second radio frequency signals generated after the N sub-first baseband signals are processed by the above-mentioned first processing device 12, optical splitter 13, and second processing device 14, sub-first radio-frequency signals and sub-second radio-frequency signals One-to-one correspondence according to frequency points.
  • the sub-first baseband signal converted into the sub-first radio frequency signal also has a one-to-one correspondence with the sub-second baseband signal converted into the sub-second radio frequency signal of the same frequency point of the sub-first radio frequency signal.
  • the nonlinear compensation device 112 is configured to perform nonlinear compensation on the sub-first baseband signal according to the sub-first baseband signal and the sub-second baseband signal corresponding to the sub-first baseband signal. It should be understood that the steps performed by the baseband resource pool 111 can refer to the steps performed by the digital processing device 11 for generating the first baseband signal, and the steps performed by the non-linear compensation device 112 can refer to the steps performed by the digital processing device 11 for non-linear compensation. step.
  • the baseband resource pool 111 may include N baseband resources, and each baseband resource is used to generate a sub-first baseband signal. It should be noted that the wavelength of the optical signal in the embodiment of the present application is 1310 nm.
  • the dispersion characteristics of the optical signal will cause nonlinear distortion. This phenomenon is particularly serious in the transmission process of optical signals with a wavelength of 1550 nm, and in the transmission process of optical signals with a wavelength of 1310 nm. , The dispersion phenomenon is not obvious.
  • Current optical fiber communication systems mostly use optical signals with a wavelength of 1550 nm. Therefore, it is necessary to compensate for nonlinear distortion caused by dispersion in the transmission of optical signals in this frequency band.
  • the nonlinear distortion caused by the dispersion of the optical signal in the RoF network system is relatively low and can be ignored.
  • the performance of the RoF network system can be improved as a whole by performing local compensation for the non-linearity of the devices in the center-side communication device in the embodiment of the present application.
  • the technical solutions in the embodiments of the present application can also be applied to optical fiber communication systems with a wavelength of 1550 nm and other different wavelengths.
  • a feedback link is established in the center-side communication device, and the feedback link is used to feed back the baseband signal with nonlinear distortion processed by the device in the center-side communication device, and the center-side communication
  • the device can compensate the nonlinear distortion of the baseband signal according to the generated baseband signal and the signal fed back by the feedback link, so as to improve the signal transmission quality.
  • the structure of the center-side communication device in the embodiment of the present application can compensate for the nonlinear distortion in the RoF network system. It can also avoid the need to establish a feedback link between the central-side communication device and the remote-side communication device to introduce additional optical fiber and introduce complicated control logic, thereby simplifying the configuration of the remote side.
  • the baseband resource pool 111 can generate N sub-first baseband signals with different frequency points.
  • the structure of the RoF network system is explained.
  • the following embodiment two and embodiment three describe the structure of the RoF network system when N is 1, and the embodiments four to seven describe the structure of the RoF network system when N is greater than 1.
  • the first baseband signal in the second to seventh embodiments is a digital baseband signal.
  • FIG. 10 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • the first processing device 12 in the center-side communication device 10 of the embodiment of the present application may include: a digital-to-analog conversion device 121DAC, a first mixer 122, a band-pass filter 123, and electro-optical conversion (electro-optical conversion).
  • the second processing device 14 may include: an optical-electro (O/E) device 141, a second mixer 142, a low-pass filter 143, and an analog-to-digital conversion device 144 ADC.
  • the structure of the RoF network system provided in the second embodiment is suitable for single-wavelength single-frequency baseband signals, and the electro-optical conversion device 124 in the embodiment of the present application may be EML or DML.
  • a photoelectric conversion (optical-electro, O/E) device may also be called a photodetector (PD).
  • the digital-to-analog conversion device 121 is connected to the non-linear compensation device 112 and the first mixer 122 respectively, and the band-pass filter 123 is connected to the first mixer 122 and the electro-optical conversion device 124 respectively, and the first mixer 122 also Connected to the local oscillator 15, the electro-optical conversion device 124 is also connected to the optical splitter 13; the second mixer 142 is connected to the photoelectric conversion device 141, the low-pass filter 143, and the local oscillator 15, respectively, and the analog-to-digital conversion device 144 is connected to the The low-pass filter 143 and the nonlinear compensation device 112 are connected.
  • the digital-to-analog conversion device 121 is configured to convert the first baseband signal into a first digital baseband signal, and output the first digital baseband signal to the first mixer 122.
  • the first mixer 122 is configured to perform an up-conversion operation on the first digital baseband signal, and convert the first digital baseband signal into a first radio frequency signal at a corresponding frequency through the local oscillator 15, and output the first radio frequency signal to the band Pass filter 123.
  • the band pass filter 123 is configured to filter the first radio frequency signal to filter out interference signals in the first radio frequency signal, and output the filtered first radio frequency signal to the electro-optical conversion device 124.
  • the electro-optical conversion device 124 is configured to convert the received first radio frequency signal into an optical signal, and output the optical signal to the optical splitter 13.
  • the photoelectric conversion device 141 is configured to convert the second optical signal into a second electrical domain signal, and output the second electrical domain signal to the second mixer 142.
  • the second mixer 142 is used for down-converting the second electric domain signal, and converts the second electric domain signal into a second radio frequency signal with the same frequency as the first radio frequency signal through the local oscillator 15, so as to convert The second radio frequency signal is output to the low pass filter 143.
  • the low-pass filter 143 is configured to filter the second radio frequency signal to filter out interference signals in the second radio frequency signal, and output the filtered second radio frequency signal to the analog-to-digital conversion device 144.
  • the analog-to-digital conversion device 144 is used to convert the second radio frequency signal into a second baseband signal and output it to the nonlinear compensation device 112.
  • the power of the signal input to the second mixer 142 is not greater than -20 dBm (approximately equal to 0.008 mW), and when the power of the signal input to the second mixer 142 is -21 dBm during actual measurement, The nonlinear compensation effect of RoF network system is the most obvious. Similarly, when the power of the signal input to the ADC analog-to-digital conversion device 144 is too small, the nonlinearity of the RoF network system is submerged in noise and cannot be used for subsequent nonlinear compensation operations.
  • the signal when the power of the signal input to the analog-to-digital conversion device 144 is -6.7dBm (approximately equal to 0.214mW), the signal will not cause the analog-to-digital conversion device 144 to generate nonlinearity due to power overflow, and it can also ensure feedback
  • the signal (the second baseband signal) may reflect the nonlinear distortion of the RoF network system, and then the subsequent nonlinear compensation operation may be used.
  • the signal-to-noise ratio of the feedback signal when the signal-to-noise ratio of the feedback signal is about 30dB, the nonlinear compensation effect of the RoF network system is the most obvious. It should be understood that the above parameters are values determined in combination with actual hardware measurements, but the above parameters may be different for different types of hardware devices and algorithms.
  • the first processing device 12 may further include: an adjustable attenuator 125 and a low noise amplifier 126.
  • the adjustable attenuator 125 is connected to the band pass filter 123 and the low noise amplifier 126 respectively, and the low noise amplifier 126 is also connected to the electro-optical conversion device 124.
  • the adjustable attenuator 125 is used to adjust the power of the first radio frequency signal.
  • the low noise amplifier 126 is used to reduce noise in the first radio frequency signal.
  • the first processing device 12 may further include: an optical domain amplifier 127 (erbium doped fiber application amplifier, EDFA), and the optical domain amplifier 127 is connected to the electro-optical conversion device 124 and the optical splitter 13 respectively.
  • the optical domain amplifier 127 is used to amplify the power of the optical signal.
  • the second processing device 14 may further include: an electrical domain amplifier 145, which is connected to the low-pass filter 143 and the analog-to-digital conversion device 144, respectively.
  • the electric domain amplifier 145 is used to amplify the power of the second radio frequency signal.
  • the second processing device 14 may further include: an electrical domain amplifier 145, which is connected to the digital-to-analog conversion device 121 and the low-pass filter 143, respectively.
  • the third processing device 21 in the remote-side communication device 20 may include: a photoelectric conversion device 141.
  • the photoelectric conversion device 141 and the optical splitter 13 are connected by an optical fiber, and the photoelectric conversion device 141 is used to convert the first optical signal into a radio frequency signal and output it to the antenna 22.
  • the antenna 22 can output radio frequency signals.
  • the nonlinear compensation device 112 may include: a digital predistortion module 1121 and a parameter estimation module 1122.
  • the digital predistortion module 1121 is connected to the baseband resource pool 111, the first processing device 12, and the second processing device 14 respectively.
  • the digital predistortion module 1121 is connected to the digital-to-analog conversion device 121 in the first processing device 12.
  • the parameter estimation module 1122 is connected to the digital predistortion module 1121 and the analog-to-digital conversion device 144 in the second processing device 14 respectively.
  • the digital predistortion module 1121 is configured to perform predistortion processing on the first baseband signal by using distortion parameters.
  • the distortion parameter can be predefined.
  • the parameter estimation module 1122 is configured to update the distortion parameter according to the first baseband signal and the second baseband signal to perform nonlinear compensation on the first baseband signal.
  • the method adopted in the embodiments of the present application is a model-based DPD nonlinear compensation method, and the model is not limited to a polynomial model or a neural network model.
  • DPD technology was first invented to compensate for nonlinear distortion caused by power amplifiers. The researchers then introduced this technology into the RoF network system to compensate for the nonlinear distortion of the system. DPD technology assumes that the nonlinear distortion of the system can be represented by a polynomial model, such as Volterra polynomial, memory polynomia (MP), generalized memory polynomial (GMP), and Wiener-Hammerstein (WH) polynomials, etc. .
  • MP memory polynomia
  • GMP generalized memory polynomial
  • WH Wiener-Hammerstein
  • FIG. 11 is a schematic diagram of one-dimensional DPD nonlinear compensation provided by an embodiment of this application.
  • the input signal (such as the first baseband signal) of the system is x(n)
  • the output signal (such as the first baseband signal) is y(n)
  • a km represents the parameter of the nonlinear term when the nonlinear distortion in the RoF network system is k-order and the memory depth is m
  • k is the order of the nonlinear distortion in the RoF network system
  • m is the parameter in the RoF network system.
  • the inverse distortion model can be established according to the above input signal and output signal, as shown in the following formula 2:
  • w km represents the updated distortion parameter.
  • the digital predistortion module 1121 in the embodiment of the present application may use the distortion parameter w km in the above formula 2 to perform predistortion processing on the first baseband signal A to obtain the predistorted baseband signal B, and the parameter estimation module 1122 Get the second baseband signal C that is fed back.
  • the parameter estimation module 1122 Get the second baseband signal C that is fed back.
  • the updated distortion parameters are obtained by solving w km.
  • the updated distortion parameter is used to perform predistortion processing on the first baseband signal, so that the first baseband signal is processed by the first processing device 12 to obtain a linear optical signal, so as to improve the quality of the optical signal.
  • the algorithm for solving the updated distortion parameter in the embodiment of the present application is not limited to the least square method, the least mean square method, the singular value decomposition method, and the like.
  • direct learning or indirect learning may be used to solve the updated distortion parameters. It should be understood that direct learning and indirect learning are two training methods commonly used in digital predistortion technology. The direct learning method is to directly compare the transmitted signal with the feedback signal and then update the distortion parameter. Indirect learning is to perform post-compensation on the feedback signal, then compare it with the transmitted signal, and update the distortion parameters based on the difference between the two.
  • the structure of the remote-side communication device 20 is the same as that in the first embodiment, and will not be repeated here.
  • the structure of the RoF network system provided by the embodiment of the application can perform nonlinear compensation for the baseband signal of a single wavelength and single frequency point.
  • the DPD nonlinear compensation method adopted in the embodiments of the present application can compensate for the nonlinear distortion caused by the memory characteristics of the device, and is suitable for various types of electro-optical conversion devices.
  • the non-linear compensation method in the embodiments of the present application is adopted because the second baseband signal is introduced through the other non-linear compensation methods.
  • the signal processed by the linear compensation device therefore, in the embodiment of the present application, the nonlinear compensation is performed according to the first baseband signal and the second baseband signal, and the nonlinear distortion caused by other devices that introduce nonlinear compensation can also be compensated.
  • FIG. 12 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • the structure and connection relationship of the first processing device 12 and the second processing device 14 in the central side communication device 10 of the embodiment of the present application can refer to the related description in the second embodiment above, and the remote side communicates
  • the structure of the device 20 reference may also be made to the related description in the second embodiment above, which is not repeated here.
  • the structure of the RoF network system provided in the third embodiment is suitable for single-wavelength single-frequency baseband signals, and the digital predistortion module 1121 is used for predistorting the first baseband signal by using distortion parameters deal with.
  • the electro-optical conversion device 124 in the embodiment of the present application is an EML.
  • the parameter estimation module 1122 is configured to obtain the difference between the preset bias voltage and the half-wave voltage of the external modulator according to the first baseband signal and the second baseband signal, and then update the distortion according to the difference Parameters to perform nonlinear compensation on the first baseband signal.
  • v ⁇ represents the half-wave voltage of the EML
  • v DC represents the preset bias voltage
  • ⁇ v represents the difference between the half-wave voltage of the EML and the preset bias voltage
  • P out represents the power of the optical signal output by the EML
  • v( t) represents the voltage of the RF signal input to the EML.
  • FIG. 13 is a schematic diagram of nonlinear compensation of EML provided by an embodiment of the application. As shown in FIG. 13, assuming that the amplitude of the first radio frequency signal input to the EML is v(t), the second radio frequency signal output from the O/E terminal is v out (t). It has the following formula six:
  • R represents the equivalent resistance of the O/E terminal
  • G represents the link loss from EML to O/E
  • E in represents the power of the signal input to the EML
  • ⁇ represents the loss at the O/E terminal.
  • ⁇ v The value of ⁇ v can be obtained by solving the nine equations in the following formula.
  • the updated distortion parameter U(n) can be obtained according to the above formula eight, as shown in the following formula ten:
  • the parameter estimation module 1122 in the embodiment of the present application stores a correspondence table of ⁇ v and U(n). After the parameter estimation module 1122 obtains the difference between the half-wave voltage of the EML and the preset bias voltage, The updated distortion parameters can be obtained by looking up the table, and then the distortion parameters can be updated.
  • the structure of the remote-side communication device 20 is the same as that in the first embodiment, and will not be repeated here.
  • the nonlinear compensation device when the electro-optical conversion device is an external modulator, can also adjust the preset bias voltage and the half-wave voltage of the external modulator according to the first baseband signal and the second baseband signal.
  • the method of the difference between the two can also achieve the compensation of the nonlinear distortion of the RoF network system.
  • the structure of the RoF network system provided in the fourth and fifth embodiments is suitable for single-wavelength multi-frequency baseband signals.
  • N is greater than 1, that is, the baseband resource pool 111 can generate N sub-first baseband signals. Therefore, the first processing device 12 and the second processing device 14 in the embodiment of this application are different from those in the second and third embodiments above. . Since the fourth and fifth embodiments include multiple first baseband signals, in the fourth and fifth embodiments, the electrical domain signals corresponding to the multiple first baseband signals can be combined.
  • the specific structure of the RoF network system See Example 4 and Example 5 below. The drawings in the following embodiments do not mark the same devices. For details, please refer to the markings in FIG. 10 above.
  • the structure of the RoF network system provided in the following four embodiments can also perform nonlinear compensation for non-linear distortions such as four-wave mixing and adjacent-wave crosstalk.
  • nonlinear distortions such as four-wave mixing and adjacent-wave crosstalk.
  • FIG. 14 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • the center-side communication device 10 in the embodiment of the present application may further include: an electric domain combiner 16 and an electric domain splitter 17.
  • the electrical domain combiner 16 is connected to the first processing device 12, and the electrical domain splitter 17 is connected to the second processing device 14.
  • the first processing device 12 in the embodiment of the present application is specifically configured to convert the sub-first baseband signal into a sub-first radio frequency signal, and output the sub-first radio frequency signal to the electric domain combiner 16.
  • the electrical domain combiner 16 is used to combine N sub-first radio frequency signals, and output the combined radio frequency signals to the first processing device 12.
  • the electric domain combiner 16 combines the N sub-first radio frequency signals into one radio frequency signal.
  • the first processing device 12 is specifically also used to convert the combined radio frequency signal into an optical signal.
  • the manner in which the first processing device 12 converts the sub-first baseband signal into the sub-first radio frequency signal may refer to the manner in which the first processing device 12 converts the first baseband signal into the first radio frequency signal in the first embodiment.
  • the manner in which the first processing device 12 converts the combined radio frequency signal into an optical signal can refer to the manner in which the first processing device 12 converts the first radio frequency signal into an optical signal in the first embodiment.
  • the second processing device 14 in the embodiment of the present application is specifically configured to convert the second optical signal into a second radio frequency signal and output it to the electrical domain splitter 17.
  • the electrical domain splitter 17 is configured to split the second radio frequency signal into N sub-second radio frequency signals, and output the N sub-second radio frequency signals to the second processing device 14.
  • the N sub-second radio frequency signals correspond to the N sub-first radio frequency signals in a one-to-one correspondence according to frequency points.
  • the second processing device 14 is specifically used to convert the sub-second radio frequency signals into sub-second baseband signals to obtain N sub-second baseband signals.
  • the manner in which the second processing device 14 converts the second optical signal into the second radio frequency signal can refer to the second processing device 14 in the first embodiment for converting the optical signal into the second radio frequency signal.
  • the manner in which the second processing device 14 converts the sub-second radio frequency signal into a sub-second baseband signal refer to the manner in which the second processing device 14 converts the second radio frequency signal into a second baseband signal in the first embodiment. .
  • FIG. 15 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • the first processing module includes an electro-optical conversion device 124 and N digital-to-analog conversion devices 121
  • the second processing device 14 includes: a photoelectric conversion device 141 and N analog-to-digital conversion devices.
  • the device 144 there are N local oscillators 15 and one local oscillator 15 corresponds to one digital-to-analog conversion device 121 and one analog-to-digital conversion device 144.
  • the electric domain combiner 16 is connected to the N digital-to-analog conversion devices 121 and the electro-optical conversion device 124, and the N digital-to-analog conversion devices 121 are also connected to the nonlinear compensation device 112.
  • Each local oscillator 15 is connected to a corresponding digital
  • the analog conversion device 121 and the analog-to-digital conversion device 144 are connected, the optical splitter 13 is respectively connected to the electro-optical conversion device 124 and the photoelectric conversion device 141, and the electrical domain splitter 17 is respectively connected to the photoelectric conversion device 141 and N analog-to-digital conversion devices 144 ,
  • the N analog-to-digital conversion devices 144 are all connected to the non-linear compensation device 112.
  • the digital-to-analog conversion device 121 in the embodiment of the present application is used to convert the sub-first baseband signal into a sub-first radio frequency signal, and output the sub-first radio frequency signal to the electric domain combiner 16.
  • the electro-optical conversion device 124 is used for converting the combined radio frequency signal into an optical signal.
  • the photoelectric conversion device 141 is used to convert the second optical signal into a second radio frequency signal and output it to the electrical domain splitter 17.
  • the analog-to-digital conversion device 144 is used for converting the sub-second radio frequency signal into a sub-second baseband signal.
  • the first processing device 12 may further include: N first mixers 122, N band pass filters 123, and one digital-to-analog conversion device 121 corresponds to one first mixer.
  • the second processing device 14 further includes: N second mixers 142 and N low-pass filters 143, and an analog-to-digital conversion device 144 corresponds to a first Two mixers 142, a low-pass filter 143, and a local oscillator 15.
  • each first mixer 122 is connected to the corresponding digital-to-analog conversion device 121, band-pass filter 123, and local oscillator 15, and each band-pass filter 123 is also connected to the electrical domain combiner 16, and each first The second mixer 142 is connected to the corresponding low-pass filter 143, the local oscillator 15, and the electrical domain splitter 17.
  • the first processing device 12 further includes: N adjustable attenuators 125, N low-noise amplifiers 126, and one band-pass filter 123 corresponds to one Tuning attenuator 125, a low noise amplifier 126.
  • each adjustable attenuator 125 is connected to the corresponding band pass filter 123 and the low noise amplifier 126 respectively, and the N low noise amplifiers 126 are also connected to the electric domain combiner 16.
  • the first processing device 12 further includes: an optical domain amplifier 127; the optical domain amplifier 127 is connected to the electro-optical conversion device 124 and the optical splitter 13 respectively.
  • the second processing device 14 further includes: N electrical domain amplifiers 145, one electrical domain amplifier 145 corresponds to a digital-to-analog conversion device 121, and a low-pass filter Each electrical domain amplifier 145 is connected to a corresponding digital-to-analog conversion device 121 and a low-pass filter 143.
  • the nonlinear compensation device 112 in the embodiment of the present application may be based on the sub-first baseband signal and the sub-second baseband signal corresponding to the sub-first baseband signal. Signal to perform nonlinear compensation on the sub-first baseband signal.
  • FIG. 16 is a schematic diagram of multi-dimensional DPD nonlinear compensation provided by an embodiment of the application. Similar to the second embodiment above, as shown in Figure 16, suppose the input signal of the system includes x1(n), x2(n)...xn(n), where x1(n), x2(n)... xn(n) are all sub-first baseband signals, and the output signals of the system include y1(n), y2(n)...yn(n), among them, y1(n), y2(n)...yn(n) They are all sub-second baseband signals.
  • the DPD nonlinear compensation method can also be used in the embodiment of the present application, but the difference from the second embodiment is that the first baseband signal in the embodiment of the present application includes There are multiple channels of first baseband signals, four-wave mixing generated during optical signal transmission, adjacent-wave crosstalk and other nonlinear distortions, so it is necessary to use a multi-dimensional model for DPD nonlinear compensation.
  • a multi-dimensional model can be established first and stored in the nonlinear compensation device 112.
  • the multi-dimensional model can be a polynomial model or a neural network model without limitation.
  • the multi-dimensional model is established based on multiple channels of first baseband signals and feedback multiple channels of second baseband signals.
  • the multi-dimensional model also contains intermodulation terms between multiple signals.
  • FIG. 17 is a schematic diagram showing the performance of intermodulation and crosstalk between multi-frequency baseband signals provided by an embodiment of the application. As shown in Fig. 17, the abscissa in Fig. 17 is the sub-first baseband signal of 3 frequency points, and the ordinate is the power of the signal.
  • the midline frequencies of the sub-first baseband signals of the three frequency points are 200MHz, 400MHz, and 600MHz, respectively.
  • the sub-first baseband signals of the three frequency points will produce intermodulation and crosstalk during transmission, as shown in Figure 17
  • the solid line represents the interference signal.
  • the DPD nonlinear compensation method can not only compensate for the nonlinear distortion of a single baseband signal in the transmission process, but also compensate for the intermodulation and crosstalk between multiple baseband signals.
  • Non-linear distortion the one-dimensional model refers to the model adopted in the second embodiment.
  • the nonlinear compensation device 112 in the embodiment of the present application includes: a digital predistortion module 1121 and a parameter estimation module 1122.
  • the digital predistortion module 1121 is configured to perform predistortion processing on the sub-first baseband signal by using distortion parameters.
  • the parameter estimation module 1122 is configured to update the distortion parameters according to the sub-first baseband signal, the sub-second baseband signal, and the multi-dimensional model, and perform nonlinear compensation with the sub-first baseband signal.
  • the parameter estimation module 1122 in the embodiment of the present application can obtain the updated distortion parameter based on the N sub-first baseband signals and the fed back N sub-second baseband signals, as well as the multi-dimensional model, so as to obtain the updated distortion parameter for each sub-first baseband signal.
  • the baseband signal is subjected to nonlinear compensation, so that the optical signal obtained by processing the compensated sub-first baseband signal through the first processing device 12 does not have nonlinear distortion.
  • the way of performing DPD nonlinear compensation with the above-mentioned multi-dimensional model is suitable for the electro-optical conversion device 124 to be EML or DML.
  • the method for nonlinear compensation performed by the nonlinear compensation device 112 in the embodiment of the present application may also use the compensation method in the third embodiment above.
  • the parameter estimation module 1122 is configured to obtain the difference between the preset bias voltage and the half-wave voltage of the external modulator corresponding to the sub-baseband signal according to the first sub-baseband signal and the sub-second baseband signal, and then Adjust the difference to perform nonlinear compensation with the sub-first baseband signal.
  • the structure of the remote-side communication device 20 is the same as that in the first embodiment, and will not be repeated here.
  • the structure of the RoF network system establishes a feedback link in the central side communication device, which can perform nonlinear compensation for the baseband signal of single wavelength and multiple frequency points, and can not only compensate for the single-channel baseband signal in the transmission process
  • Non-linear distortion can also compensate for non-linear distortion caused by intermodulation and crosstalk between multiple baseband signals.
  • FIG. 18 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • the center-side communication device 10 in the embodiment of the present application may further include: an electric domain combiner 16 and N electric domain switches 18.
  • the electric domain combiner 16 is connected to the first processing device 12
  • the electric domain switch 18 is connected to the local oscillator 15 and the second processing device 14 respectively
  • one electric domain switch 18 corresponds to a sub-first radio frequency signal.
  • the first processing device 12 in the embodiment of the present application is specifically configured to convert the sub-first baseband signal into a sub-first radio frequency signal, and output the sub-first radio frequency signal to the electric domain combiner 16.
  • the electrical domain combiner 16 is used to combine N sub-first radio frequency signals, and output the combined radio frequency signals to the first processing device 12.
  • the electric domain combiner 16 combines the N sub-first radio frequency signals into one radio frequency signal.
  • the first processing device 12 is specifically also used to convert the combined radio frequency signal into an optical signal. It should be understood that the manner in which the first processing device 12 converts the sub-first baseband signal into the sub-first radio frequency signal and the manner in which the first processing device 12 converts the combined radio frequency signal into an optical signal can refer to the second embodiment above. Related description in.
  • the second processing device 14 in the embodiment of the present application is specifically configured to convert the second optical signal into a second radio frequency signal.
  • the electrical domain switch 18 is used to control the on/off of the feedback link of the sub-second radio frequency signal corresponding to the sub-first radio frequency signal.
  • a possible implementation manner for the electrical domain switch 18 to control the on/off of the feedback link of the sub-second radio frequency signal may be: the electrical domain switches 18 corresponding to the N sub-first radio frequency signals follow a preset rule, It can be turned on and off in sequence at intervals of a preset time to control the second radio frequency signal corresponding to the electrical domain switch 18 after the feedback link is turned on, and then the second radio frequency signal is fed back to the nonlinear compensation device 112. After the second radio frequency signal is fed back to the nonlinear compensation device 112, the electric domain switch 18 can be closed to control the feedback link of the second radio frequency signal corresponding to the electric domain switch 18 to be disconnected.
  • the preset rule may be to turn on the sub-first radio frequency signal 1, the sub-first radio frequency signal 2... the electrical domain switch 18 corresponding to the sub-first radio frequency signal N in order every 1 ms, so that the sub-second radio frequency signal 1.
  • the second radio frequency signal 2... the feedback link of the second radio frequency signal N is turned on in turn, and the second radio frequency signal 1, the second radio frequency signal 2... the second radio frequency signal N is fed back to Non-linear compensation device 112.
  • the electric domain switch 18 controls the sub-second radio frequency signal corresponding to the electric domain switch 18 according to the control command.
  • the on and off of the feedback link may be generated by the center-side communication device 10 according to the status of the uplink signal, or may also be manually input to control the on/off of the feedback link of the sub-second radio frequency signal corresponding to the frequency point.
  • the center-side communication device 10 determines that the quality of the uplink signal of a frequency point is poor according to the received uplink signal, it can control the electrical domain switch corresponding to the frequency point to be closed to feed back the sub-number of the frequency point. Two baseband signals to perform nonlinear compensation on the signal at the frequency point to improve the quality of the signal at the frequency point.
  • the electrical domain switch 18 determines the feedback chain of the sub-second radio frequency signal corresponding to the frequency point according to the uplink signal. Road conduction. Specifically, the center-side communication device 10 determines the frequency point in the working state according to the uplink signal, and then controls the feedback link of the second radio frequency signal of the frequency point to be turned on.
  • the center-side communication device 10 determines the frequency point in the working state according to the uplink signal, and other frequency points are in the non-working state (sleep state), therefore, the center-side communication device 10 can control the frequency point corresponding to the work
  • the feedback link of the second radio frequency signal is turned on to perform nonlinear compensation on the signal at the frequency point in the working state.
  • the second processing device 14 is specifically also used to convert the feedback sub-second radio frequency signal into a sub-second baseband signal. It should be understood that the manner in which the second processing device 14 converts the second optical signal into a second radio frequency signal and the manner in which the second processing device 14 converts the feedback sub-second radio frequency signal into a sub-second baseband signal can be referred to above Related description in the second embodiment.
  • FIG. 19 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • the first processing module includes an electro-optical conversion device 124 and N digital-to-analog conversion devices 121
  • the second processing device 14 includes: a photoelectric conversion device 141 and an analog-to-digital conversion device 144 ,
  • N local oscillators 15 and one local oscillator 15 corresponds to one digital-to-analog conversion device 121 and one electrical domain switch 18.
  • the electric domain combiner 16 is respectively connected to N digital-to-analog conversion devices 121 and electro-optical conversion device 124, and the N digital-to-analog conversion devices 121 are also connected to the nonlinear compensation device 112.
  • Each local oscillator 15 is connected to a corresponding digital-to-analog converter.
  • the conversion device 121 and the electrical domain switch 18 are connected.
  • the optical splitter 13 is respectively connected to the electro-optical conversion device 124 and the photoelectric conversion device 141.
  • the analog-to-digital conversion device 144 is respectively connected to the photoelectric conversion device 141, N electrical domain switches 18, and nonlinear compensation.
  • the device 112 is connected.
  • the digital-to-analog conversion device 121 in the embodiment of the present application is used to convert the sub-first baseband signal into a sub-first radio frequency signal, and output the sub-first radio frequency signal to the electric domain combiner 16.
  • the electro-optical conversion device 124 is used for converting the combined radio frequency signal into an optical signal.
  • the photoelectric conversion device 141 is used for converting the second optical signal into a second radio frequency signal, and under the action of the electric domain switch 18, controls the on/off of the feedback link of the second radio frequency signal in the second radio frequency signal.
  • the analog-to-digital conversion device 144 is used to convert the feedback sub-second radio frequency signal into a sub-second baseband signal.
  • the first processing device 12 may further include: the first processing module further includes: N first mixers 122, N bandpass filters 123, and a digital-to-analog converter
  • the device 121 corresponds to a first mixer 122, a band-pass filter 123, and a local oscillator 15;
  • the second processing device 14 further includes: a second mixer 142 and a low-pass filter 143.
  • the digital-to-analog conversion device 121, the band-pass filter 123 and the local oscillator 15 corresponding to each first mixer 122 are connected, and each local oscillator 15 is connected to the second mixer 142 through a corresponding electric domain switch 18,
  • the second mixer 142 is connected to the low-pass filter 143, and the low-pass filter 143 is also connected to the analog-to-digital conversion device 144.
  • the electrical domain switches 18 are all connected to the second mixer 142.
  • the first processing device 12 further includes: N adjustable attenuators 125 and N low-noise amplifiers 126.
  • N adjustable attenuators 125 and N low-noise amplifiers 126 For the introduction of the adjustable attenuator 125 and the low-noise amplifier 126, reference may be made to the related description of the fourth embodiment above.
  • the first processing device 12 further includes: an optical domain amplifier 127.
  • an optical domain amplifier 127 For the introduction of the optical domain amplifier 127, reference may be made to the related description of the fourth embodiment above.
  • the second processing device 14 further includes: an electrical domain amplifier 145, which is connected to the digital-to-analog conversion device 121 and the low-pass filter 143, respectively.
  • the compensation method of the non-linear compensation device 112 in the embodiment of the present application can refer to the related description in the fourth embodiment, which is not repeated here.
  • the structure of the remote-side communication device 20 is the same as that in the first embodiment, and will not be repeated here.
  • the structure of the RoF network system establishes a feedback link in the central-side communication device, which can perform nonlinear compensation for single-wavelength and multi-frequency baseband signals, and an electrical domain switch is set in the central-side communication device.
  • an electrical domain switch is set in the central-side communication device.
  • the repeated arrangement of components can be reduced, and the cost can be saved.
  • the electrical domain switch through the control of the electrical domain switch, it is also possible to realize nonlinear compensation for the baseband signal at a specific frequency point, and the selectivity is higher.
  • the structure of the RoF network system provided in the fourth and fifth embodiments above is suitable for single-wavelength multi-frequency baseband signals.
  • the structure of the RoF network system provided in the sixth and seventh embodiments below is suitable for multi-wavelength and multi-frequency baseband signals. Baseband signal.
  • the wavelength division multiplexer 19 and the wavelength division multiplexer 19' can be set to combine and split the multiple optical signals. For details of the structure, see the sixth embodiment and the seventh embodiment below.
  • FIG. 20 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • the center-side communication device 10 in the embodiment of the present application may further include: a wavelength division multiplexer 19 and a wavelength division multiplexer 19'.
  • the wavelength division multiplexer 19 is connected to the first processing device 12 and the optical splitter 13 respectively
  • the wavelength division multiplexer 19 ′ is connected to the optical splitter 13 and the second processing device 14 respectively.
  • the first processing device 12 in the embodiment of the present application is specifically configured to convert the sub-first baseband signal into a sub-first radio frequency signal, and convert the sub-first radio frequency signal into a sub-first optical signal, so as to obtain N sub-first optical signals.
  • the optical signal, the optical signal includes N sub-first optical signals.
  • the wavelength division multiplexer 19 is used to combine the N sub-first optical signals and output the combined optical signal to the optical splitter 13. It should be understood that the wavelength division multiplexer 19 combines the N sub-first optical signals The combined path is an optical signal.
  • the wavelength division multiplexer 19' is used to split the second optical signal into N sub-second optical signals.
  • the second processing device 14 is specifically configured to convert the sub-second optical signal into a sub-second radio frequency signal and convert the sub-second radio frequency signal into a sub-second baseband signal to obtain N sub-second baseband signals.
  • the manner in which the first processing device 12 in the embodiment of the present application converts the sub-first baseband signal into the sub-first radio frequency signal converts the sub-first baseband signal into the sub-first radio frequency signal
  • the manner in which the sub-first radio frequency signal is converted into the sub-first optical signal converts the sub-second optical signal into the sub-second radio frequency signal
  • the second processing For the manner in which the device 14 converts the sub-second optical signal into the sub-second radio frequency signal and converts the sub-second radio frequency signal into the sub-second baseband signal, reference may be made to the related description in the first embodiment.
  • FIG. 21 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • the first processing module includes N digital-to-analog conversion devices 121, N electro-optical conversion devices 124, one digital-to-analog conversion device 121 corresponds to one electro-optical conversion device 124
  • the second The processing device 14 includes: N photoelectric conversion devices 141 and N analog-to-digital conversion devices 144, one photoelectric conversion device 141 corresponds to one analog-to-digital conversion device 144, local oscillators 15 are N, and one local oscillator 15 corresponds to one digital-to-analog conversion device 121.
  • An analog-to-digital conversion device 144 is an analog-to-digital conversion device 144.
  • the nonlinear compensation device 112 is connected to N digital-to-analog conversion devices 121, each digital-to-analog conversion device 121 is connected to the corresponding electro-optical conversion device 124 and the local oscillator 15, and the wavelength division multiplexer 19 is respectively connected to the N electro-optical conversion devices. 124.
  • the optical splitter 13 is connected, and the wavelength division multiplexer 19' is respectively connected to N photoelectric conversion devices 141 and the optical splitter 13, and each analog-to-digital conversion device 144 is also connected to a corresponding photoelectric conversion device 141 and local oscillator. 15 connections, N analog-to-digital conversion devices 144 are all connected to the non-linear compensation device 112.
  • the digital-to-analog conversion device 121 is configured to convert the sub-first baseband signal into a sub-first radio frequency signal, and output the sub-first radio frequency signal to the electro-optical conversion device 124.
  • the electro-optical conversion device 124 is used to convert the sub-first radio frequency signal into the sub-first optical signal, and output to the wavelength division multiplexer 19.
  • the photoelectric conversion device 141 is used for converting the sub-second optical signal into a sub-second radio frequency signal and outputting the sub-second radio frequency signal to the analog-to-digital conversion device 144.
  • the analog-to-digital conversion device 144 is configured to convert the sub-second optical signal into a sub-second radio frequency signal, and convert the sub-second radio frequency signal into a sub-second baseband signal.
  • the first processing device 12 may further include: the first processing module further includes: N first mixers 122, N bandpass filters 123, and a digital-to-analog converter
  • the device 121 corresponds to a first mixer 122, a band-pass filter 123, and a local oscillator 15.
  • the second processing device 14 also includes: N second mixers 142 and N low-pass filters 143, one modulus
  • the digital conversion device 144 corresponds to a second mixer 142, a low-pass filter 143, and a local oscillator 15.
  • each first mixer 122 is connected to a corresponding digital-to-analog conversion device 121, a band-pass filter 123 and a local oscillator 15, and each band-pass filter 123 is also connected to a corresponding electro-optical conversion device 124.
  • Each second mixer 142 is connected to the corresponding low-pass filter 143, the local oscillator 15, and the photoelectric conversion device 141.
  • the first processing device 12 further includes: N adjustable attenuators 125, N low-noise amplifiers 126, and one band-pass filter 123 corresponds to one Tuning attenuator 125, a low-noise amplifier 126, and an electro-optical conversion device 124.
  • each adjustable attenuator 125 is respectively connected to a corresponding band pass filter 123 and a low noise amplifier 126, and each low noise amplifier 126 is also connected to a corresponding electro-optical conversion device 124.
  • the first processing device 12 further includes: an optical domain amplifier 127, which is connected to the wavelength division multiplexer 19 and the optical splitter 13 respectively .
  • the second processing device 14 further includes: N electrical domain amplifiers 145.
  • N electrical domain amplifiers 145 For the introduction of the electrical domain amplifiers 145, reference may be made to the related description of the fourth embodiment above.
  • the compensation method of the non-linear compensation device 112 in the embodiment of the present application can refer to the related description in the fourth embodiment above, which will not be repeated here.
  • the third processing device 21 includes: a wavelength division multiplexer 19' and N photoelectric conversion devices 141, and there are N antennas 22 , One photoelectric conversion device 141 corresponds to one antenna 22.
  • the wavelength division multiplexer 19 ′ is respectively connected to the optical splitter 13 and N photoelectric conversion devices 141, and each photoelectric conversion device 141 is also connected to the corresponding antenna 22.
  • the wavelength division multiplexer 19' is used to split the first optical signal into N sub-optical signals and output them to the corresponding photoelectric conversion device 141.
  • the photoelectric conversion device 141 is used to convert the sub-optical signal into a sub-radio frequency signal and output the sub-radio frequency signal to the antenna 22.
  • the antenna 22 is used to transmit the sub-radio frequency signal.
  • the structure of the RoF network system establishes a feedback link in the central side communication device, which can perform nonlinear compensation for the baseband signal of single wavelength and multiple frequency points, and can not only compensate for the single-channel baseband signal in the transmission process
  • Non-linear distortion can also compensate for non-linear distortion caused by intermodulation and crosstalk between multiple baseband signals.
  • FIG. 22 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • the center-side communication device 10 in the embodiment of the present application may further include: 2N electrical domain switches 18. Among them, N electric domain switches 18 are set in the feedback link.
  • the local oscillator 15 is connected to N electric domain switches 18, and the N electric domain switches 18 are also connected to the second processing device 14.
  • One electric domain switch 18 corresponds to a sub-first radio frequency signal
  • the second processing device 14 also It is connected to the remaining N electrical domain switches 18, one electrical domain switch 18 corresponds to one sub-second radio frequency signal, and one sub-first radio frequency signal corresponds to one sub-second radio frequency signal.
  • the electrical domain switch 18 is used to control the on/off of the feedback link of the sub-second radio frequency signal corresponding to the sub-first radio frequency signal.
  • the electrical domain switch 18 controls the on-off of the feedback link of the second radio frequency signal.
  • the second processing device 14 is specifically configured to convert the feedback sub-second radio frequency signal into a sub-second baseband signal.
  • FIG. 23 is a schematic structural diagram of a RoF network system according to another embodiment provided by an embodiment of this application.
  • the first processing module includes: N digital-to-analog conversion devices 121, N electro-optical conversion devices 124, one digital-to-analog conversion device 121 corresponds to one electro-optical conversion device 124, and the first
  • the second processing device 14 includes: N photoelectric conversion devices 141 and analog-to-digital conversion devices 144, one photoelectric conversion device 141 corresponds to one electric domain switch 18, the number of local oscillators 15 is N, and one local oscillator 15 corresponds to one digital-to-analog conversion device 121, An electric domain switch 18 and an analog-to-digital conversion device 144.
  • the nonlinear compensation device 112 is connected to N digital-to-analog conversion devices 121, each digital-to-analog conversion device 121 is connected to a corresponding electro-optical conversion device 124 and a local oscillator 15, and each local oscillator 15 is also connected to a corresponding electric domain switch 18.
  • the wavelength division multiplexer 19 is connected to the N electro-optical conversion devices 124 and the optical splitter 13 respectively, and the wavelength division multiplexer 19' is respectively connected to the N optoelectronic conversion devices 141 and the optical splitter 13.
  • the conversion device 141 is connected to the corresponding electrical domain switch 18, the 2N electrical domain switches 18 are all connected to the analog-to-digital conversion device 144, and the analog-to-digital conversion device 144 is also connected to the nonlinear compensation device 112.
  • the digital-to-analog conversion device 121 is configured to convert the sub-first baseband signal into a sub-first radio frequency signal, and output the sub-first radio frequency signal to the electro-optical conversion device 124.
  • the electro-optical conversion device 124 is used to convert the first radio frequency signal into a first optical signal, and output to the wavelength division multiplexer 19.
  • the photoelectric conversion device 141 is used for converting the sub-second optical signal into a sub-second radio frequency signal.
  • the electric domain switch 18 is used to control the on-off of the second radio frequency signal.
  • the analog-to-digital conversion device 144 is used to convert the feedback sub-second radio frequency signal into a sub-second baseband signal.
  • the first processing device 12 may further include: N first mixers 122, N bandpass filters 123, and one digital-to-analog conversion device 121 corresponds to one first mixer.
  • the second processing device 14 further includes: a second mixer 142 and a low-pass filter 143.
  • each first mixer 122 is connected to a corresponding digital-to-analog conversion device 121, a band-pass filter 123, and a local oscillator 15, and each local oscillator 15 is connected to a second mixer through a corresponding electrical domain switch 18 142 is connected, and each band-pass filter 123 is also connected to a corresponding electro-optical conversion device 124.
  • the second mixer 142 is also connected to the corresponding low-pass filter 143, the low-pass filter 143 is also connected to the analog-to-digital conversion device 144, and the remaining N electrical domain switches are all connected to the second mixer 142.
  • the first processing device 12 further includes: N adjustable attenuators 125, N low-noise amplifiers 126, and one band-pass filter 123 corresponds to one Tuning attenuator 125, a low-noise amplifier 126, and an electro-optical conversion device 124.
  • N adjustable attenuators 125, N low-noise amplifiers 126, and one band-pass filter 123 corresponds to one Tuning attenuator 125, a low-noise amplifier 126, and an electro-optical conversion device 124.
  • the first processing device 12 further includes: an optical domain amplifier 127.
  • an optical domain amplifier 127 For the introduction of the optical domain amplifier 127, reference may be made to the related description of the sixth embodiment.
  • the second processing device 14 further includes: N electrical domain amplifiers 145.
  • N electrical domain amplifiers 145 For the introduction of the electrical domain amplifiers 145, reference may be made to the related description of the fourth embodiment above.
  • the compensation method of the non-linear compensation device 112 in the embodiment of the present application can refer to the related description in the fourth embodiment above, which will not be repeated here.
  • FIG. 22 and FIG. 23 for the structure of the remote-side communication device 20 in the embodiment of the present application, reference may be made to the related description of the sixth embodiment.
  • the structure of the RoF network system establishes a feedback link in the central side communication device, which can perform nonlinear compensation for the baseband signal of single wavelength and multiple frequency points, and can not only compensate for the single-channel baseband signal in the transmission process
  • Non-linear distortion can also compensate for non-linear distortion caused by intermodulation and crosstalk between multiple baseband signals.
  • the electric domain switch is arranged in the communication equipment on the center side. Compared with the sixth embodiment, the repeated arrangement of components can be reduced, and the cost can be saved.
  • through the control of the electrical domain switch it is also possible to realize nonlinear compensation for the baseband signal at a specific frequency point, and the selectivity is higher.
  • the embodiment of the present application also provides a communication system, as shown in FIG. 9, FIG. 10, FIG. 12, FIG. 14-15, and FIG. 18-23.
  • the communication system includes a central side communication device and at least one remote side communication device.
  • the remote-side communication device includes an antenna.
  • the remote-side communication device is used to convert the first optical signal from the central-side communication device into a radio frequency signal, and transmit the radio frequency signal through an antenna. It should be understood that the structure of the center-side communication device and the remote-side communication device in the embodiments of the present application are specifically described in the foregoing Embodiment 1 to Embodiment 7.

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Abstract

本申请实施例提供一种通信设备和通信系统，本申请实施例通过在中心侧通信设备中建立反馈链路，该反馈链路用于反馈经中心侧通信设备中的器件处理后的具有非线性失真的基带信号，中心侧通信设备可以根据生成的基带信号和该反馈链路反馈的信号，对基带信号的非线性失真进行补偿，以提高信号的传输质量。因为RoF网络系统中的非线性失真主要发生在中心侧通信设备中，因此本申请实施例中的中心侧通信设备的结构，可以在能够对RoF网络系统中的非线性失真进行补偿的前提下，还能够避免了需要在中心侧通信设备和远端侧通信设备之间建立反馈链路引入的额外拉设光纤，以及引入复杂的控制逻辑的问题，进而够简化了远端侧的设置。

Description

通信设备和通信系统
本申请要求于2020年04月30日提交国家知识产权局、申请号为202010361731.4、申请名称为“通信设备和通信系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请实施例涉及通信技术，尤其涉及一种通信设备和通信系统。
背景技术
光载无线通信(radio over fiber，RoF)技术是将光纤通信和无线通信结合起来的通信技术。RoF系统包括中心侧通信设备和远端侧通信设备，中心侧通信设备中集成有电光信号转换装置，远端侧通信设备中集成有光电转换装置。中心侧通信设备将生成的基带信号转换为射频信号，且经由电光信号转换装置将射频信号转换为光信号，再经光纤传输至远端侧通信设备。远端侧通信设备通过光电转换装置将接收到的光信号转换为射频信号，进而通过天线发射射频信号，以供用户终端接入使用。
电光信号转换装置在信号转换过程中易产生非线性失真，进而造成传输至远端侧通信设备的光信号的质量低。现有技术中，为了消除该非线性失真，远端侧通信设备中还可以集成有电光信号转换装置，将部分射频信号通过天线发射，部分射频信号经光电信号转换装置转换为光信号后反馈至中心侧通信设备。中心侧通信设备将反馈的光信号转换为基带信号后与其输出的基带信号进行比对分析，以确定基带信号失真情况，进而调整基带信号的参数，以补偿信号转换过程中的非线性失真。
但现有技术中的非线性失真的补偿方法，需要由远端侧通信设备反馈光信号，为了避免额外拉设光纤传输该光信号，该光信号和上行数据共享同一条链路。该种方式需要在中心侧通信设备和远端侧通信设备设置额外的控制逻辑，以实现中心侧通信设备对上行数据与反馈的光信号之间的切换，复杂度高。
发明内容
本申请实施例提供一种通信设备和通信系统，能够对RoF网络系统中的非线性失真进行补偿的前提下，还能够避免了远端侧通信设备建立反馈链路引入的复杂设置。
第一方面，本申请实施例提供一种通信设备，包括：数字处理装置、第一处理装置、光分路器、第二处理装置和本振，所述第一处理装置分别与所述数字处理装置、所述本振、所述光分路器连接，所述光分路器还与所述第二处理装置连接，所述第二处理装置还与所述本振、所述数字处理装置连接。
本申请实施例中，所述数字处理装置，用于生成第一基带信号，且将所述第一基带信号输出至所述第一处理装置；所述第一处理装置，用于将所述第一基带信号转换为第一射频信号，且将所述第一射频信号转换为光信号，以及将所述光信号输出至所述光分路器；所述光分路器，用于将所述光信号分路为第一路光信号和第二路光信号，且将所述第一路光信号输 出至至少一个远端通信设备，将所述第二路光信号输出至所述第二处理装置；所述第二处理装置，用于将所述第二路光信号转换为第二射频信号，且将所述第二射频信号转换为第二基带信号，以及将所述第二基带信号输出至所述数字处理装置；所述数字处理装置，还用于根据所述第一基带信号和所述第二基带信号，对所述第一基带信号进行非线性补偿。
本申请实施例中，因为RoF网络系统中的非线性失真主要发生在中心侧通信设备中，因此本申请实施例中在中心侧通信设备中建立反馈链路，可以在能够对RoF网络系统中的非线性失真进行补偿的前提下，还能够避免了需要在中心侧通信设备和远端侧通信设备之间建立反馈链路引入的额外拉设光纤，以及引入复杂的控制逻辑的问题，进而够简化了远端侧的设置。
应理解，在一种可能的实现方式中，本申请实施例中的所述数字处理装置包括：基带资源池和非线性补偿装置，所述基带资源池和所述非线性补偿装置连接，所述非线性补偿装置还分别与所述第一处理装置、所述第二处理装置连接。
其中，所述基带资源池，用于生成所述N个子第一基带信号，且将所述N个子第一基带信号经由所述非线性补偿装置输出至所述第一处理装置；所述第一处理装置，具体用于将子第一基带信号转换为子第一射频信号，且将所述N个子第一射频信号转换为所述光信号；所述第二处理装置，具体用于将所述第二路光信号转换为所述N个子第二射频信号，且将所述子第二射频信号转换为所述子第二基带信号；所述非线性补偿装置，用于根据所述子第一基带信号，以及与所述子第一基带信号对应的子第二基带信号，对所述子第一基带信号进行非线性补偿。
应注意，本申请实施例中的所述第一基带信号包括N个子第一基带信号，所述第二基带信号包括N个子第二基带信号，所述第一射频信号包括N个子第一射频信号，所述第二射频信号包括N个子第二射频信号，所述子第一射频信号与所述子第二射频信号按照频点一一对应，N为大于或等于1的整数。
本申请实施例中的光信号的波长可以为1310nm。应注意，本申请实施例中针对波长为1310nm的光信号，RoF网络系统中因为光信号的色散造成的非线性失真较低，可以忽略不计。因此，本申请实施例中针对中心侧通信设备中的器件的非线性进行本地补偿就可以整体的改善RoF网络系统的性能。但应注意的是，本申请实施例中的技术方案也可以应用在波长为1550nm的光信号对应的光纤通信系统，以及其他不同波长的光纤通信系统中。
应注意，当N等于1，以及N大于1时，本申请实施例中的通信设备中的第一处理装置、第二处理装置的结构设置不同。因此，下述从等于1，以及N大于1时两个方面对通信设备的结构进行说明。
其中，当N等于1时，本申请实施例中提供的通信设备的结构适用于单波长单频点的信号的非线性失真的补偿。
在一种可能的实现方式中，第一处理装置可以包括：数模转换装置、第一混频器、带通滤波器、电光转换装置；第二处理装置可以包括：光电转换装置、第二混频器、低通滤波器和模数转换装置。其中，数模转换装置分别与非线性补偿装置、第一混频器连接，带通滤波器分别与第一混频器、电光转换装置连接，第一混频器还与本振连接，电光转换装置还与光分路器连接；第二混频器分别与光电转换装置、低通滤波器、本振连接，模数转换装置分别与低通滤波器、非线性补偿装置连接。应理解，发明内容中未对通信设备中的每个器件的功能进行介绍，具体的功能可以参照下述实施例中的相关描述，发明内容对通信设备中的可能的结构进行展开介绍。
在该种方式中，第一处理装置还可以包括：可调衰减器和低噪声放大器。其中，可调衰减器分别与带通滤波器、低噪声放大器连接，低噪声放大器还与电光转换装置连接。可选的，第一处理装置还可以包括：光域放大器，该光域放大器分别与电光转换装置、光分路器连接。光域放大器，用于放大光信号的功率。可选的，第二处理装置还可以包括：电域放大器，该电域放大器分别与低通滤波器、模数转换装置连接。电域放大器，用于放大第二射频信号的功率。可选的，第二处理装置还可以包括：电域放大器，电域放大器分别与数模转换装置、低通滤波器连接。
在该种方式中，与该中心侧网络设备的结构相对应的，远端侧通信设备中的第三处理装置可以包括：光电转换装置。其中，光电转换装置与光分路器通过光纤连接，光电转换装置，用于将第一路光信号转换为射频信号，且输处至天线。天线可以将射频信号输出。
其中，本申请实施例中的电光转换装置可以为EML或DML，下面针对电光转换装置为EML或DML时的非线性补偿装置的补偿方式进行介绍，应理解，本实施例中的非线性补偿装置包括：数字预失真模块和参数估计模块。
第一种方式：所述电光转换装置为外部调制器或直接调制器。
其中，所述数字预失真模块，用于采用失真参数对所述第一基带信号进行预失真处理。所述参数估计模块，用于根据所述第一基带信号和所述第二基带信号，更新所述失真参数，以对所述第一基带信号进行非线性补偿。应理解，该第一种方式采用的非线性补偿方式为一维DPD非线性补偿的方式。其中，一维DPD非线性补偿的方式为采用一维DPD模型进行非线性补偿，该一维DPD模型不限于多项式模型和神经网络模型。
第二种方式：所述电光转换装置为外部调制器。
其中，所述数字预失真模块，用于采用失真参数对所述第一基带信号进行预失真处理；所述参数估计模块，用于根据所述第一基带信号和所述第二基带信号，获取预设偏置电压与所述外部调制器的半波电压之间的差值；根据所述差值，更新所述失真参数，以对所述第一基带信号进行非线性补偿。应理解，该第一种方式采用的非线性补偿方式为外部调制器EML的半波电压与预设偏置电压的差值进行补偿的方式。
其中，当N大于1时，下面首先从两种可能实现的方式对通信设备的结构进行说明，该两种可能实现的方式中的通信设备的结构适用于单波长多频点的信号的非线性失真的补偿。
一种可能的实现方式中，所述通信设备还包括电域合路器和电域分路器，所述电域合路器与所述第一处理装置连接，所述电域分路器与所述第二处理装置连接。其中，所述第一处理装置，具体用于将所述子第一基带信号转换为子第一射频信号，且将所述子第一射频信号输出至所述电域合路器；所述电域合路器，用于合路N个子第一射频信号，且将合路后的射频信号输出至所述第一处理装置；所述第一处理装置，具体还用于将所述合路后的射频信号转换为所述光信号。所述第二处理装置，具体用于将所述第二路光信号转换为第二射频信号，并输出至所述电域分路器；所述电域分路器，用于将所述第二射频信号分路为N个子第二射频信号，且将N个子第二射频信号输出至第二处理装置；所述第二处理装置，具体还用于将所述子第二射频信号转换为所述子第二基带信号，以得到所述N个子第二基带信号。
在该种方式中，第一处理模块包括电光转换装置和N个数模转换装置，所述第二处理装置包括：光电转换装置和N个模数转换装置，所述本振为N个，且一个本振对应一个数模转换装置、一个模数转换装置。
所述电域合路器分别与所述N个数模转换装置、所述电光转换装置连接，所述N个数模转换装置还与所述非线性补偿装置连接，每个本振分别与对应的数模转换装置、模数转换装置 连接，所述光分路器分别所述电光转换装置、所述光电转换装置连接，所述电域分路器分别与所述光电转换装置、所述N个模数转换装置连接，所述N个模数转换装置均与所述非线性补偿装置连接。
可选的，在该种方式中，相应的，所述第一处理模块还包括：N个第一混频器、N个带通滤波器，一个数模转换装置对应一个第一混频器、一个带通滤波器、一个本振；所述第二处理装置还包括：N个第二混频器和N个低通滤波器，一个模数转换装置对应一个第二混频器、一个低通滤波器、一个本振。可选的，所述第一处理装置还包括：N个可调衰减器、N个低噪声放大器，一个带通滤波器对应一个可调衰减器、一个低噪声放大器。可选的，所述第一处理装置还包括：光域放大器。可选的，所述第二处理装置还包括：电域放大器。应理解，该种方式中的器件的连接方式可以参照下述实施例四。
一种可能的实现方式中，所述通信设备包括电域合路器和N个电域开关。其中，所述电域分路器与所述第二处理装置连接，所述电域开关分别与所述本振、所述第二处理装置连接，一个电域开关对应一个子第一射频信号。
第一处理装置的处理方式可以参照上述可能的实现方式中的相关介绍。所述第二处理装置，具体用于将所述第二路光信号转换为第二射频信号；电域开关，用于控制子第一射频信号对应的子第二射频信号的反馈链路的通断；所述第二处理装置，具体还用于将反馈的子第二射频信号转换为子第二基带信号。该种方式中，通过对电域开关的控制，可以实现对特定频点的子第二基带信号的反馈，进而对该频点的信号进行非线性补偿。
在该种方式中，所述第一处理模块包括电光转换装置和N个数模转换装置，所述第二处理装置包括：光电转换装置和模数转换装置，所述本振为N个，且一个本振对应一个数模转换装置、一个电域开关；所述电域合路器分别与所述N个数模转换装置、所述电光转换装置连接，所述N个数模转换装置还与所述非线性补偿装置连接，每个本振与对应的数模转换装置、电域开关连接，所述光分路器分别与所述电光转换装置、所述光电转换装置连接，所述模数转换装置分别与所述光电转换装置、所述N个电域开关、所述非线性补偿装置连接。
可选的，在该种方式中，相应的，所述第一处理模块还包括：N个第一混频器、N个带通滤波器，一个数模转换装置对应一个第一混频器、一个带通滤波器、一个本振；所述第二处理装置还包括：第二混频器和低通滤波器。可选的，所述第一处理装置还包括：N个可调衰减器、N个低噪声放大器，一个带通滤波器对应一个可调衰减器、一个低噪声放大器。可选的，所述第一处理装置还包括：光域放大器。可选的，所述第二处理装置还包括：电域放大器。应理解，该种方式中的器件的连接方式可以参照下述实施例五。
其中，当N大于1时，上述两种可能实现的方式中的通信设备的结构适用于单波长多频点的信号的非线性失真的补偿，下述提供的两种可能的实现方式中的通信设备的结构适用于多波长多频点的信号的非线性失真的补偿。
在一种可能的实现方式中，所述通信设备还包括波分复用器和波分解复用器，所述波分复用器分别与所述第一处理装置、所述光分路器连接，所述波分解复用器分别与所述光分路器、所述第二处理装置连接。其中，所述第一处理装置，具体用于将所述子第一基带信号转换为子第一射频信号，且将所述子第一射频信号转换为子第一光信号，以得到N个子第一光信号，所述光信号包括所述N个子第一光信号；所述波分复用器，用于合路所述N个子第一光信号，并将合路后的光信号输出至所述光分路器；所述波分解复用器，用于将所述第二路光信号分路为N个子第二光信号；所述第二处理装置，具体用于将所述子第二光信号转换为子第二射频信号，且将所述子第二射频信号转换为所述子第二基带信号，以得到N个子第二基 带信号。
在该种方式中，所述第一处理模块包括N个数模转换装置、N个电光转换装置，一个数模转换装置对应一个电光转换装置，所述第二处理装置包括：N个光电转换装置和N个模数转换装置，一个光电转换装置对应一个模数转换装置，所述本振为N个，一个本振对应一个数模转换装置、一个模数转换装置；其中，所述非线性补偿装置与所述N个数模转换装置连接，每个数模转换装置与对应的电光转换装置、本振连接，所述波分复用器分别与所述N个电光转换装置、所述光分路器连接，所述波分解复用器分别与所述N个光电转换装置、所述光分路器连接，每个模数转换装置还与对应的光电转换装置、本振连接，所述N个模数转换装置均与所述非线性补偿装置连接。
可选的，在该种方式中，相应的，所述第一处理模块还包括：N个第一混频器、N个带通滤波器；所述第二处理装置还包括：N个第二混频器和N个低通滤波器。可选的，所述第一处理装置还包括：N个可调衰减器、N个低噪声放大器。可选的，所述第一处理装置还包括：光域放大器。可选的，所述第二处理装置还包括：电域放大器。应理解，该种方式中的器件的连接方式可以参照下述实施例六。
在一种可能的实现方式中，所述通信设备还包括波分复用器和波分解复用器，波分复用器和波分解复用器的连接方式和功能可以参照上述可能的实现方式中的介绍。在此基础上，该种方式中的所述通信设备还包括：2N个电域开关。其中，所述本振与其中的N个电域开关连接，所述N个电域开关还与第二处理装置连接，一个电域开关对应一个子第一射频信号，所述第二处理装置还与剩余N个电域开关连接，一个电域开关对应一个子第二射频信号，一个子第一射频信号对应一个子第二射频信号。电域开关，用于控制子第一射频信号对应的子第二射频信号的反馈链路的通断；所述第二处理装置，具体还用于将反馈的子第二射频信号转换为子第二基带信号。该种方式中，通过对电域开关的控制，可以实现对特定频点的子第二基带信号的反馈，进而对该频点的信号进行非线性补偿。
在该种方式中，所述第一处理模块包括N个数模转换装置、N个电光转换装置，一个数模转换装置对应一个电光转换装置，所述第二处理装置包括：N个光电转换装置和模数转换装置，一个光电转换装置对应一个电域开关，所述本振为N个，一个本振对应一个数模转换装置、一个电域开关、一个模数转换装置。其中，所述非线性补偿装置与所述N个数模转换装置连接，每个数模转换装置与对应的电光转换装置、本振连接，每个本振还与对应的电域开关连接，所述波分复用器分别与N个电光转换装置、所述光分路器连接，所述波分解复用器分别与所述N个光电转换装置、所述光分路器连接，每个光电转换装置与对应的电域开关连接，所述2N个电域开关均与所述模数转换装置连接，所述模数转换装置还与所述非线性补偿装置连接。
可选的，在该种方式中，相应的，所述第一处理模块还包括：N个第一混频器、N个带通滤波器；所述第二处理装置还包括：第二混频器和低通滤波器。可选的，所述第一处理装置还包括：N个可调衰减器、N个低噪声放大器。可选的，所述第一处理装置还包括：光域放大器。可选的，所述第二处理装置还包括：电域放大器。应理解，该种方式中的器件的连接方式可以参照下述实施例七。
应理解，在上述当N大于1时本申请实施例提供的通信设备的结构的基础上，下面针对电光转换装置为EML或DML时的非线性补偿装置的补偿方式进行介绍，应理解，本实施例中的非线性补偿装置包括：数字预失真模块和参数估计模块。
第一种方式：所述电光转换装置为外部调制器或直接调制器。
其中，所述数字预失真模块，用于采用失真参数对子第一基带信号进行预失真处理。所述参数估计模块，用于根据子第一基带信号和子第二基带信号，更新所述失真参数，以对所述子第一基带信号进行非线性补偿。应理解，该第一种方式采用的非线性补偿方式为多维DPD非线性补偿的方式。其中，该多维DPD模型不限于多项式模型和神经网络模型。其中，采用多维DPD模型进行补偿的方式，不仅可以补偿单路基带信号在传输过程中的非线性失真，还能够补偿因为多路基带信号之间的交调和串扰引起的非线性失真。
第二种方式：所述电光转换装置为外部调制器。
其中，所述数字预失真模块，用于采用失真参数对子第一基带信号进行预失真处理；所述参数估计模块，用于根据子第一基带信号和子第二基带信号，获取预设偏置电压与所述外部调制器的半波电压之间的差值；根据所述差值，更新所述失真参数，以对子第一基带信号进行非线性补偿。应理解，该种方式中，对子第一基带信号进行非线性补偿的方式可以参照上述方式中对第一基带信号进行非线性补偿的相关描述。
上述第一方面中可选方式所具有的其他效果将在下文中结合具体实施例加以说明。
第二方面，本申请实施例提供一种通信系统，包括如上述第一方面所述的通信设备和远端侧通信设备，其中，上述第一方面所述的通信设备为拉远通信系统中的中心侧通信设备。应理解，另外，远端侧通信设备，用于将来自中心侧通信设备的第一路光信号转换为射频信号，且将所述射频信号通过天线发射。
本申请实施例提供一种通信设备和通信系统，该通信设备为中心侧通信设备，本申请实施例中在中心侧通信设备中建立反馈链路，该反馈链路用于反馈经中心侧通信设备中的器件处理后的具有非线性失真的基带信号，中心侧通信设备可以根据生成的基带信号和该反馈链路反馈的信号，对基带信号的非线性失真进行补偿，以提高信号的传输质量。因为RoF网络系统中的非线性失真主要发生在中心侧通信设备中，因此本申请实施例中的中心侧通信设备的结构，可以在能够对RoF网络系统中的非线性失真进行补偿的前提下，还能够避免了需要在中心侧通信设备和远端侧通信设备之间建立反馈链路引入的额外拉设光纤，以及引入复杂的控制逻辑的问题，进而够简化了远端侧的设置。
附图说明
图1为现有技术中通过同轴线缆传输信号的拉远网络系统的结构示意图；
图2为现有技术中的CPRI网络系统的结构示意图；
图3为现有技术中的光载无线电网络系统的结构示意图；
图4为现有技术中提供的RoF网络系统中电光转换装置的结构示意图一；
图5为现有技术中提供的RoF网络系统中电光转换装置的结构示意图二；
图6为现有技术中提供的RoF网络系统中电光转换装置的结构示意图三；
图7为现有技术中提供的RoF网络系统的结构示意图；
图8为本申请实施例提供的RoF网络系统架构示意图；
图9为本申请实施例提供的一实施例的RoF网络系统的结构示意图；
图10为本申请实施例提供的另一实施例的RoF网络系统的结构示意图；
图11为本申请实施例提供的一维DPD非线性补偿的示意图；
图12为本申请实施例提供的另一实施例的RoF网络系统的结构示意图；
图13为本申请实施例提供的EML的非线性补偿的示意图；
图14为本申请实施例提供的另一实施例的RoF网络系统的结构示意图；
图15为本申请实施例提供的另一实施例的RoF网络系统的结构示意图；
图16为本申请实施例提供的多维DPD非线性补偿的示意图；
图17为本申请实施例提供的多频点基带信号之间的交调和串扰表现示意图；
图18为本申请实施例提供的另一实施例的RoF网络系统的结构示意图；
图19为本申请实施例提供的另一实施例的RoF网络系统的结构示意图；
图20为本申请实施例提供的另一实施例的RoF网络系统的结构示意图；
图21为本申请实施例提供的另一实施例的RoF网络系统的结构示意图；
图22为本申请实施例提供的另一实施例的RoF网络系统的结构示意图；
图23为本申请实施例提供的另一实施例的RoF网络系统的结构示意图。
附图标记说明：
10-中心侧通信设备；
20-远端侧通信设备；
11-数字处理装置；
12-第一处理装置；
13-光分路器；
14-第二处理装置；
15-本振；
16-电域合路器；
17-电域分路器；
18-电域开关；
19-波分复用器；
19'-波分解复用器。
111-基带资源池；
112-非线性补偿装置；
1121-数字预失真模块；
1122-参数估计模块；
121-数模转换装置；
122-第一混频器；
123-带通滤波器；
124-电光转换装置；
125-可调衰减器；
126-低噪声放大器；
127-光域放大器；
141-光电转换装置；
142-第二混频器；
143-低通滤波器；
144-模数转换装置；
145-电域放大器；
21-第三处理装置；
22-天线。
具体实施方式
拉远网络系统由中心侧通信设备和至少一个远端侧通信设备组成，中心侧通信设备生成基带信号，远端侧通信设备将基带信号转换成的射频信号发射出去，以供用户终端接入使用。
图1为现有技术中通过同轴线缆传输信号的拉远网络系统的结构示意图。如图1所示，在该拉远网络系统中，中心侧通信设备10和远端侧通信设备图之间通过同轴线缆连接。中心侧通信设备10包括基带信号处理单元(digital unit，DU)和射频信号处理单元(radio unit，RU)，远端侧通信设备20包括射频信号发射单元，射频信号发射单元如射频头端(radio head，RH)。
中心侧通信设备10生成基带信号，且通过DU和RU将基带信号转换为射频信号，进而通过同轴线缆将射频信号传输至远端侧通信设备20。远端侧通信设备20通过RH可以将接收到的射频信号发射出去。在数字CPRI拉远网络中，射频信号通过同轴线缆传输，传输速率低。
图2为现有技术中的CPRI网络系统的结构示意图。如图2所示，在数字通用公共无线电接口(common public radio interface，CPRI)拉远网络系统，以及增强型CPRI(enhanced-CPRI，eCPRI)拉远网络系统中，中心侧通信设备10和远端侧通信设备20之间通过光纤连接，中心侧通信设备10包括DU，远端侧通信设备20包括RU和RH。中心侧通信设备10生成基带信号后，且将基带信号通过光纤传输至远端侧通信设备20。远端侧通信设备20可以通过RU将基带信号转换为射频信号，且通过RH将射频信号发射出去。其中，CPRI和eCPRI网络系统中虽然采用光纤传输基带信号，相较于通过同轴线缆传输信号的传输速率加快，但相较于下述图3中的光载无线电网络系统，信号的传输速率仍较低。
图3为现有技术中的光载无线电网络系统的结构示意图。如图3所示，在光载无线通信(radio over fiber，RoF)拉远网络系统中，中心侧通信设备10包括DU、RU、以及电光信号转换装置，远端侧通信设备20包括光电转换装置和RH。中心侧通信设备将生成的基带信号转换为射频信号，且经由电光信号转换装置将射频信号转换为光信号，再经光纤传输至远端侧通信设备。远端侧通信设备通过光电转换装置将接收到的光信号转换为射频信号，进而通过RH将射频信号发射出去。
RoF网络系统简化了远端侧通信设备的设置，将DU、RU、以及电光信号转换装置等多个器件设置在中心侧通信设备中，可以有效降低远端侧通信设备的成本，且便于快速布局远端侧通信设备，以提高网络覆盖。由于在RoF网络系统中，需要通过电光转换装置将射频信号转换为光信号，而电光转换装置在信号转换的过程中容易产生非线性失真，且光信号在传输的过程中由于色散也会造成光信号的非线性失真，进而造成RoF网络系统中传输的光信号存在非线性失真，导致光信号的质量低。
图4为现有技术中提供的RoF网络系统中电光转换装置的结构示意图一。如图4所示，该RoF网络系统结构中的电光转换装置为外部调制器(external modulation laser，EML)，该EML中可以包括偏置电压调整单元和色散补偿单元。其中，电光转换装置在信号转换过程中产生的非线性失真可以造成电光转换装置的偏置电压的变化，因此图4中可以通过偏置电压调整单元对电光转换装置的偏置电压进行调整，以消除该电光转换装置在信号转换过程中产生的非线性失真。另外，色散补偿单元还可以对光信号的色散造成的非线性失真进行非线性补偿，以消除光信号的传输引起的非线性失真。
但图4中的补偿方法仅考虑电光转换装置为EML时的非线性补偿，该补偿方法并不是适用于电光转换装置为直接调制器(direct modulator laser，DML)的场景，适用性有限。且该补偿方式中的色散补偿单元对非线性失真的补偿效果与光信号波长以及光纤长度有关，补偿效果的鲁棒性差且成本高。另外，该补偿方式中也并未考虑EML的记忆特性引起的非线性失真。应理解，记忆特性是信号传输过程中前一段时刻传输的信号对后续传输的信号具有影响的特性，这个特性是跟器件相关的固有特性。
非线性失真可以包括低阶非线性失真和高阶非线性失真。其中，高阶非线性失真对光信号的质量的影响更大，因此在上述图4的基础上，为了进一步提高负非线性失真的补偿的效果，图5中提供了一种对高阶非线性失真的补偿方法。图5为现有技术中提供的RoF网络系统中电光转换装置的结构示意图二。如图5所示，该RoF网络系统结构中的电光转换装置为外部调制器EML，该EML中可以包括高阶非线性失真补偿单元，该高阶非线性失真补偿单元包括偏置电压调整单元和色散补偿单元。与上述图4不同的是，其中的色散补偿单元针对二阶非线性失真进行补偿，偏置电压调整单元针对三阶或者更高阶的非线性失真进行补偿，因此图5中的非线性补偿方法的补偿效果更为显著。但图5中的方法仍存在上述如图4中相同的问题。
为了解决上述图4和图5中的非线性补偿方法中的问题，图6中提供了一种基于记忆多项式的数字化预失真(digital pre-distortion，DPD)的非线性补偿的方法。其中，图6为现有技术中提供的RoF网络系统中电光转换装置的结构示意图三。如图6所示，该RoF网络系统结构中的电光转换装置可以为EML或DML，且该电光转换装置包括DPD补偿单元，DPD补偿单元根据输入电光转换装置的信号和输出电光转换装置输出的信号，对电光转换装置在信号转换过程中产生的非线性失真进行非线性补偿。
鉴于DPD的非线性补偿方法可以适用于EML或DML，且还考虑了因为电光转换装置的记忆特性引起的非线性失真，因此可以提高非线性补偿的效果。但图6中的非线性补偿方法仅适用于电光转换装置中，并未考虑RoF网络系统中其他通常包含的器件，如功率放大器(power amplifier，PA)等造成的非线性失真，因此RoF网络系统还会存在非线性失真。应注意，DPD的非线性补偿方法可以参照下述本申请实施例中对DPD的非线性补偿方法的相关描述。
为了进一步解决上述图6中的技术问题，图7提供了一种基于记忆多项式的数字化预失真(digital pre-distortion，DPD)的非线性补偿的方法。其中，图7为现有技术中提供的RoF网络系统的结构示意图。如图7所示，该RoF网络系统中同样也包括中心侧通信设备10和远端侧通信设备20，其中，中心侧通信设备10和远端侧通信设备20中的器件的设置具体可以参考上述图3。
与上述图3不同的是，图7中的远端侧通信设备20中还包括射频信号分路装置，且RoF网络系统中还包括反馈链路。其中，射频信号分路装置将来自光电信号转换装置的部分射频信号发射出去，将另一部分射频信号输出至反馈链路。该反馈链路中，在远端侧通信设备20包括电光转换装置，另一部分射频信号经光电信号转换装置转换为光信号后反馈至中心侧通信设备，中心侧通信设备10将反馈的光信号转换为基带信号后与其输出的基带信号进行比对分析，以确定基带信号非线性失真情况，进而调整基带信号的参数，以补偿信号转换过程中的非线性失真。
图7所示的方法中虽然能够补偿因为RoF网络系统中因为其他器件的设置引起的非线性失真，但图7中的方法需要由远端侧通信设备反馈光信号，因此需要在中心侧通信设备和远 端侧通信设备之间需要额外拉设光纤，建立一条反馈链路。现有技术中为了避免引入额外的光纤传输远端侧通信设备反馈的光信号，可以该光信号和上行数据共享同一条链路(如图7中用于连接电光信号转换装置和光电信号转换装置的光纤)，但该种方式需要在中心侧通信设备和远端侧通信设备设置额外的控制逻辑，以实现中心侧通信设备对上行数据与反馈的光信号之间的切换，复杂度高。
现有的RoF网络系统简化了远端侧通信设备的设置，中心侧通信设备中集成有DU、RU、以及电光信号转换装置等多个器件，因此RoF网络系统中的非线性失真主要发生在中心侧通信设备中。因此为了解决上述技术问题，本申请实施例中通过在中心侧通信设备中建立反馈链路，在能够对RoF网络系统中的非线性失真进行补偿的前提下，还能够避免了需要在中心侧通信设备和远端侧通信设备之间建立反馈链路引入的额外拉设光纤，以及引入复杂的控制逻辑的问题，且能够简化远端侧的设置。
图8为本申请实施例提供的RoF网络系统架构示意图。如图8所示，RoF网络系统包括中心侧通信设备10和多个远端侧通信设备20。中心侧通信设备10和多个远端侧通信设备20之间通过光纤连接，其中，二者之间的光纤可以为5-50km。
其中，图8中的中心侧通信设备包括至少一个模拟基带处理单元(building base band unit，BBU)，每个远端侧通信设备包括射频拉远单元(radio remote unit，RRU)。本申请实施例中的RoF网络系统适用于宏站(urban area)、小站，如毫米波小站(Millimetre-wave small cell，mmWave small cell)、热点区域(hor-spot area)中等场景中。其中，远端侧通信设备可以为基站，该基站可以为GSM系统或CDMA系统中的基站(Base Transceiver Station，简称BTS)，也可以是WCDMA系统中的基站(NodeB，简称NB)，还可以是LTE系统中的演进型基站(evolved NodeB，简称eNB)、下一代基站(可统称为新一代无线接入网节点(NG-RAN node)，其中，下一代基站包括新空口基站(NR nodeB，gNB)、新一代演进型基站(NG-eNB)，在此不作限定。
下面结合具体的实施例对本申请实施例中的中心侧通信设备的结构进行说明。下面这几个实施例可以相互结合，且这几个实施例中公开的中心侧通信设备的结构之间可以相互参考，对于采用下述实施例中的器件进行组合或通过器件位置的调整得到的方案均属于本申请实施例的保护范围。对于相同或相似的概念或过程可能在某些实施例不再赘述。
图9为本申请实施例提供的一实施例的RoF网络系统的结构示意图。如图9所示，本申请实施例中的RoF网络系统包括中心侧通信设备10和至少一个远端侧通信设备，应理解，图9中示意性的以一个远端侧通信设备为例进行说明。
实施例一
本申请实施例中，中心侧通信设备10包括：数字处理装置11、第一处理装置12、光分路器13、第二处理装置14和本振15。其中，第一处理装置12分别与数字处理装置11、本振15、光分路器13连接，光分路器13还与第二处理装置14连接，第二处理装置14还与本振15、数字处理装置11连接。
其中，数字处理装置11，用于生成第一基带信号，且将第一基带信号输出至第一处理装置12。可选的，本申请实施例中的数字处理装置11可以生成基带信号的信源，如基带资源池等。
第一处理装置12，用于将第一基带信号第一射频信号，且将第一射频信号转换为光信号，以及将光信号输出至光分路器13。应理解，本申请实施例中的本振15，用于生成射频信号。 应理解，本申请实施例中的第一基带信号可以为数字基带信号。其中，第一处理装置12可以通过本振15将第一基带信号转换为第一射频信号，且将第一射频信号转换作为光信号。其中，第一处理装置12可以通过本振15将第一基带信号转换为具有特定频点的第一射频信号。
在光分路器13接收到来自第一处理装置12的光信号后，光分路器13，用于将光信号分路为第一路光信号和第二路光信号，且将第一路光信号输出至至少一个远端通信设备，将第二路光信号输出至第二处理装置14。应注意，本申请实施例中的第一路光信号和第二路光信号的波长相同，但功率不同。示例性的，本实施例中采用9:1的功率比将光信号分路为第一路光信号和第二路光信号，其中，第一路光信号的功率占比90％，第二路光信号的功率占比为10％。
在现有技术中的拉远网络系统，如CPRI/eCPRI网络系统中，中心侧通信设备10将数字基带信号转换为模拟基带信号后，且通过光纤将该模拟基带信号传输至远端侧通信设备20，光纤上传输的为模拟基带信号。而本申请实施例中的中心侧通信设备10可以将数字基带信号转换为射频信号，再将射频信号转换为光信号，且通过光纤将该光信号传输至远端侧通信设备20。
本申请实施例中，中心侧通信设备10中可以传输射频信号，而现有技术中的中心侧通信设备10中传输的为基带信号，因为基带信号为中心频点为0Hz的信号，而射频信号却可以对应不同的频点。因此，本申请实施例中的网络系统可以传输多频点的信号，而CPRI/eCPRI网络系统尽可以传输一个频点的信号。
在多通信制式存在的场景中，每种不同通信制式信号的频点不同。如通信制式可以为长期演进(long term evolution，LTE)通信制式、通用移动通信(universal mobile telecommunications system，UMTS)通信制式、无线宽带(wireless-fidelity，WIFI)通信制式、毫米波等通信制式。因此，本申请实施例中的网络系统可以应用在多通信制式共存的场景中，而CPRI/eCPRI网络系统仅适用于存在一种通信制式的场景中。
如图9所示，远端通信设备20可以包括第三处理装置21和天线22。其中，该第三处理装置21可以将第一路光信号转换为射频信号，且输出至天线22，天线22将该射频信号发射出去，以供用户接入使用。
本申请实施例中，第二处理装置14，用于将第二路光信号转换为第二射频信号，且将第二射频信号转换为第二基带信号，以及将第二基带信号输出至数字处理装置11。与上述第一处理装置12相对应的，第二基带信号为数字基带信号。本申请实施例中，第二处理装置14可以将光信号转换为电域信号，再通过本振15将电域信号转换为第二射频信号，且将第二射频信号转换为第二基带信号。应理解，本申请实施例中的第二射频信号的频点与第一射频信号的频点相同。
数字处理装置11，还用于根据第一基带信号和第二基带信号，对第一基带信号进行非线性补偿。其中，数字处理装置11能够输出第一基带信号，且还能够接收到经各器件处理后的第二基带信号，因此可以通过对第一基带信号和第二基带信号的比对分析，对第一基带信号进行非线性补偿，以消除第一基带信号的非线性失真，进而提高第一基带信号的质量，相应的，提高在RoF网络系统中传输的信号的质量。
在一种可能的实现方式中，如图9所示，本实施例中的数字处理装置11可以包括基带资源池111和非线性补偿装置112。其中，基带资源池111和非线性补偿装置112连接，非线性补偿装置112还分别与第一处理装置12、第二处理装置14连接。应理解，图9中的箭头可以表征信号传输的方向，也可以表征中心侧通信设备10中的连接，下述图示中箭头的释义同 图9。
可选的，本申请实施例中的述第一基带信号包括N个子第一基带信号，第二基带信号包括N个子第二基带信号，第一射频信号包括N个子第一射频信号，第二射频信号包括N个子第二射频信号，子第一射频信号与子第二射频信号按照频点一一对应，N为大于或等于1的整数。
基带资源池111，用于生成上述N个子第一基带信号，且将N个子第一基带信号经由非线性补偿装置112输出至第一处理装置12。相应的，第一处理装置，具体用于将子第一基带信号转换为子第一射频信号，且将N个子第一射频信号转换为光信号。第二处理装置，具体用于将第二路光信号转换为N个子第二射频信号，且将子第二射频信号转换为子第二基带信号。
应理解，N个子第一基带信号经过上述第一处理装置12、光分路器13、第二处理装置14的处理后生成的N个子第二射频信号，子第一射频信号和子第二射频信号按照频点一一对应。应理解，转换为子第一射频信号的子第一基带信号，也与该子第一射频信号相同频点的子第二射频信号转换成的子第二基带信号一一对应。
非线性补偿装置112，用于根据子第一基带信号，以及与子第一基带信号对应的子第二基带信号，对子第一基带信号进行非线性补偿。应理解，此处的基带资源池111执行的步骤可以参照上述数字处理装置11中生成第一基带信号的步骤，非线性补偿装置112执行的步骤可以参照上述数字处理装置11中进行非线性补偿的步骤。
其中，基带资源池111中可以包括N个基带资源，每个基带资源用于生成一个子第一基带信号。应注意，本申请实施例中的光信号的波长为1310nm。
应理解，在光信号传递过程中，光信号的色散特性会造成非线性失真，这一现象在波长为1550nm的光信号的传输过程中尤为严重，而在波长为1310nm的光信号的传输过程中，色散现象不明显。目前的光纤通信系统，采用的多为波长为1550nm的光信号，因此需要针对该频段的光信号的传输进行色散引起的非线性失真的补偿。而本申请实施例中针对波长为1310nm的光信号，RoF网络系统中因为光信号的色散造成的非线性失真较低，可以忽略不计。因此，本申请实施例中针对中心侧通信设备中的器件的非线性进行本地补偿就可以整体的改善RoF网络系统的性能。但应注意的是，本申请实施例中的技术方案也可以应用在波长为1550nm，以及其他不同波长的光纤通信系统中。
应注意，上述的光信号的传输均为通过光纤传输。
本申请实施例的RoF网络系统中，在中心侧通信设备中建立反馈链路，该反馈链路用于反馈经中心侧通信设备中的器件处理后的具有非线性失真的基带信号，中心侧通信设备可以根据生成的基带信号和该反馈链路反馈的信号，对基带信号的非线性失真进行补偿，以提高信号的传输质量。因为RoF网络系统中的非线性失真主要发生在中心侧通信设备中，因此本申请实施例中的中心侧通信设备的结构，可以在能够对RoF网络系统中的非线性失真进行补偿的前提下，还能够避免了需要在中心侧通信设备和远端侧通信设备之间建立反馈链路引入的额外拉设光纤，以及引入复杂的控制逻辑的问题，进而够简化了远端侧的设置。
在上述实施例的基础上，基带资源池111可以生成N个频点不同的子第一基带信号，下述实施例中分别以N为1，以及N为大于1时，对本申请实施例中提供的RoF网络系统的结构进行说明。下面的实施例二和实施例三中说明的是N为1时的RoF网络系统的结构，实施例四至实施例七中说明的是N大于1时的RoF网络系统的结构，应理解，下述实施例二至实施例七中的第一基带信号为数字基带信号。
实施例二
在上述实施例一的基础上，图10为本申请实施例提供的另一实施例的RoF网络系统的结构示意图。如图10所示，本申请实施例的中心侧通信设备10中的第一处理装置12可以包括：数模转换装置121DAC、第一混频器122、带通滤波器123、电光转换(electro-optical，E/O)装置124，第二处理装置14可以包括：光电转换(optical-electro，O/E)装置141、第二混频器142、低通滤波器143和模数转换装置144ADC。实施例二中提供的RoF网络系统的结构适用于单波长单频点的基带信号，且本申请实施例中的电光转换装置124可以为EML或DML。其中，光电转换(optical-electro，O/E)装置也可以称为光检测器(photo detector，PD)。
其中，数模转换装置121分别与非线性补偿装置112、第一混频器122连接，带通滤波器123分别与第一混频器122、电光转换装置124连接，第一混频器122还与本振15连接，电光转换装置124还与光分路器13连接；第二混频器142分别与光电转换装置141、低通滤波器143、本振15连接，模数转换装置144分别与低通滤波器143、非线性补偿装置112连接。
数模转换装置121，用于将第一基带信号转换为第一数字基带信号，且将第一数字基带信号输出至第一混频器122。第一混频器122，用于对第一数字基带信号进行上变频操作，且通过本振15将第一数字基带信号转换对应频点的第一射频信号，且将第一射频信号输出至带通滤波器123。带通滤波器123，用于对第一射频信号进行滤波，以过滤掉第一射频信号中的干扰信号，且将滤波后的第一射频信号输出至电光转换装置124。电光转换装置124，用于将接收到的第一射频信号转换为光信号，且将光信号输出至光分路器13。
相应的，光电转换装置141，用于将第二路光信号转换为第二电域信号，且将第二电域信号输出至第二混频器142。第二混频器142，用于对第二电域信号进行下变频操作，且通过本振15将第二电域信号转换为与第一射频信号的频点相同的第二射频信号，以将第二射频信号输出至低通滤波器143。低通滤波器143，用于对第二射频信号进行滤波，以过滤掉第二射频信号中的干扰信号，且将滤波后的第二射频信号输出至模数转换装置144。模数转换装置144，用于将第二射频信号转换为第二基带信号，且输出至非线性补偿装置112。
本申请实施例中，输入至第二混频器142的信号的功率不大于-20dBm(约等于0.008mW)，且在实测时输入至第二混频器142的信号的功率在-21dBm时，RoF网络系统的非线性补偿效果最明显。类似的，当输入至ADC模数转换装置144中的信号的功率过小时，则RoF网络系统的非线性被淹没在噪声之中，无法用于后续的非线性补偿操作。在实测过程中，输入至模数转换装置144中的信号的功率在-6.7dBm(约等于0.214mW)时，信号不会导致模数转换装置144因功率溢出产生非线性，而且还能保证反馈信号(第二基带信号)可以体现RoF网络系统的非线性失真，进而可以采用后续的非线性补偿操作。同样的，在实测过程中，当反馈信号的信噪比为30dB左右时，RoF网络系统的非线性补偿效果最明显。应理解，以上的参数是在结合硬件实测后确定的数值，但对于不同型号的硬件设备以及算法，上述参数可能会有所不同。
可选的，如图10虚线框中所示，第一处理装置12还可以包括：可调衰减器125和低噪声放大器126。其中，可调衰减器125分别与带通滤波器123、低噪声放大器126连接，低噪声放大器126还与电光转换装置124连接。其中，可调衰减器125，用于调节第一射频信号的功率。低噪声放大器126，用于降低第一射频信号中的噪声。
可选的，第一处理装置12还可以包括：光域放大器127(erbium doped fiber application amplifier，EDFA)，该光域放大器127分别与电光转换装置124、光分路器13连接。光域放大器127，用于放大光信号的功率。可选的，第二处理装置14还可以包括：电域放大器145，该电域放大器145分别与低通滤波器143、模数转换装置144连接。电域放大器145，用于放大第二射频信号的功率。
可选的，第二处理装置14还可以包括：电域放大器145，电域放大器145分别与数模转换装置121、低通滤波器143连接。
与实施例二中的中心侧网络设备的结构相对应的，远端侧通信设备20中的第三处理装置21可以包括：光电转换装置141。其中，光电转换装置141与光分路器13通过光纤连接，光电转换装置141，用于将第一路光信号转换为射频信号，且输处至天线22。天线22可以将射频信号输出。
上述图10所示的RoF网络系统的结构的基础上，下述对图10中的非线性补偿装置112对非线性失真的补偿方法进行说明。
如图10所示，非线性补偿装置112中可以包括：数字预失真模块1121和参数估计模块1122。其中，数字预失真模块1121分别与基带资源池111、第一处理装置12，以及第二处理装置14连接。其中，数字预失真模块1121与第一处理装置12中的数模转换装置121连接。参数估计模块1122分别与数字预失真模块1121、第二处理装置14中的模数转换装置144连接。
其中，数字预失真模块1121，用于采用失真参数对第一基带信号进行预失真处理。该失真参数可以为预先定义的。参数估计模块1122，用于根据第一基带信号和第二基带信号，更新失真参数，以对第一基带信号进行非线性补偿。应理解，本申请实施例中采用的方法为基于模型的DPD非线性补偿方法，该模型不限于多项式模型或神经网络模型。
应理解，DPD技术最早是为补偿功率放大器引起的非线性失真而发明的。随后研究人员将此技术引入到RoF网络系统中，来补偿该系统的非线性失真。DPD技术假设系统的非线性失真可以用一个多项式模型进行表示，多项式如Volterra多项式、记忆多项式(memory polynomia，MP)、广义记忆多项式(generalized memory polynomial，GMP)，以及Wiener-Hammerstein(W-H)多项式等。
以记忆多项式为例，图11为本申请实施例提供的一维DPD非线性补偿的示意图。如图11所示，假设系统的输入信号(如第一基带信号)为x(n)，输出信号(如第一基带信号)为y(n)，于是有如下公式一可以表示RoF网络系统中的非线性失真：
Figure PCTCN2021091109-appb-000001
其中，a km表示RoF网络系统中非线性失真为k阶、且记忆深度为m时的非线性项的参数，k为RoF网络系统中的非线性失真的阶数，m为RoF网络系统中的非线性失真的记忆深度。
据上述公式一，可以根据上述的输入信号和输出信号建立逆失真模型，如下公式二所示：
Figure PCTCN2021091109-appb-000002
其中，w km表示更新后的失真参数。
应理解，本申请实施例中数字预失真模块1121可以采用上述公式二中的失真参数w km对第一基带信号A进行预失真处理，以得到预失真后的基带信号B，且参数估计模块1122得到反馈的第二基带信号C。其中，若RoF网络系统中不存在非线性失真，则存在如下公式三：
C·W km -1＝A     公式三
但实际RoF网络系统中存在非线性失真，则上述公式三不成立，因此需要对w km更新，以使得上述公式三成立，因此本申请实施例中通过求解w km的方式得到更新后的失真参数，采用更新后的失真参数对第一基带信号进行预失真处理，以使得第一基带信号经过上述第一处理装置12处理后得到线性的光信号，以提高光信号的质量。
应理解，本申请实施例中求解更新后的失真参数的算法不限于最小二乘法，最小均方值 法，奇异值分解法等。另，本申请实施例中可以采用直接学习或者间接学习的方式求解更新后的失真参数。应理解，直接学习与间接学习是数字预失真技术常用的两个训练方法，直接学习方法是发送的信号与反馈的信号直接对比然后更新失真参数。间接学习是对反馈信号进行后补偿，然后与发送信号进行对比，通过两者差值的大小更新失真参数。
应注意，如图10所示，远端侧通信设备20的结构与上述实施例一中的结构相同，在此不做赘述。
本申请实施例提供的RoF网络系统的结构，能够对单波长单频点的基带信号进行非线性补偿，在中心侧通信设备中建立反馈链路的技术效果具体参照实施例一中的相关描述。且本申请实施例中采用DPD非线性补偿方法，能够对因为器件的记忆特性造成的非线性失真进行补偿，且适用于多种类型的电光转换装置。同理的，鉴于本申请实施例中还可以包括其他引入非线性补偿的器件，如光域放大器等，采用本申请实施例中的非线性补偿方法，因为第二基带信号是经由该其他引入非线性补偿的器件处理过的信号，因此本申请实施例中根据第一基带信号和第二基带信号进行非线性补偿，还可以补偿因为其他引入非线性补偿的器件造成的非线性失真。
实施例三
图12为本申请实施例提供的另一实施例的RoF网络系统的结构示意图。如图12所示，本申请实施例的中心侧通信设备10中的第一处理装置12和第二处理装置14的结构和连接关系可以参照上述实施例二中的相关描述，且远端侧通信设备20的结构也可以参照上述实施例二中的相关描述，在此不做赘述。
与上述实施例二相同的，实施例三中提供的RoF网络系统的结构适用于单波长单频点的基带信号，且数字预失真模块1121，用于采用失真参数对第一基带信号进行预失真处理。与上述实施例二不同的是，本申请实施例中的电光转换装置124为EML。相对应的，参数估计模块1122，用于根据第一基带信号和第二基带信号，获取预设偏置电压与外部调制器的半波电压之间的差值，进而根据该差值，更新失真参数，以对第一基带信号进行非线性补偿。
下述对本申请实施例中提供的通过调整预设偏置电压与外部调制器的半波电压之间的差值，以对第一基带信号进行非线性补偿的方法进行说明：
其中，本申请实施例中的O/E的工作方式理论模型如下公式四所示：
Figure PCTCN2021091109-appb-000003
且上述公式五中的v DC满足如下公式五：
Figure PCTCN2021091109-appb-000004
其中，v π表示EML的半波电压，v DC表示预设偏置电压，Δv表示EML的半波电压和预设偏置电压的差值，P out表示EML输出的光信号的功率，v(t)表示输入EML的射频信号的电压。
图13为本申请实施例提供的EML的非线性补偿的示意图。如图13所示，假设输入EML的第一射频信号的幅值为v(t)时，O/E端输出的第二射频信号为v out(t)。则具有如下公式六：
Figure PCTCN2021091109-appb-000005
其中，R表示O/E端的等效电阻，G表示EML到O/E之间的链路损耗，E in表示输入EML 的信号的功率， α表示O/E端的损耗。
在第一基带信号为X(n)，且在得到第二基带信号Y(n)后，则有如下公式七成立：
Figure PCTCN2021091109-appb-000006
因此对Y(n)求期望，即可以得到直流分量
Figure PCTCN2021091109-appb-000007
对上述公式八的彰显函数进行5阶泰勒展开，可以得到如下公式八：
Figure PCTCN2021091109-appb-000008
通过求解如下公式九方程，便可以得到Δv的值。
Figure PCTCN2021091109-appb-000009
在求解得到Δv的值后，接着根据上述公式八便可以得到更新后的失真参数U(n)，如下公式十所示：
Figure PCTCN2021091109-appb-000010
应理解，上述E[]表示求期望运算(求平均)。
可选的，本申请实施例中的参数估计模块1122中存储有Δv和U(n)的对应关系表，参数估计模块1122在得到EML的半波电压和预设偏置电压的差值后，可以通过查表得到更新后的失真参数，进而对失真参数进行更新。
应注意，如图12所示，远端侧通信设备20的结构与上述实施例一中的结构相同，在此不做赘述。
本申请实施例中，在电光转换装置为外部调制器时，非线性补偿装置还可以根据第一基带信号和第二基带信号，采用调整调整预设偏置电压与外部调制器的半波电压之间的差值的方式，同样也能够达到对RoF网络系统的非线性失真的补偿。
实施例四和实施例五提供的RoF网络系统的结构适用于单波长多频点的基带信号。其中，因为N大于1，即基带资源池111可以生成N个子第一基带信号，因此本申请实施例中的第一处理装置12和第二处理装置14与上述实施例二和实施例三中不同。鉴于实施例四和实施例五包括多路子第一基带信号，因此实施例四和实施例五中可以对该多路子第一基带信号对应的电域信号进行合路，具体的RoF网络系统的结构见下述实施例四和实施例五。下述实施例中的附图对于相同的器件不做标识，具体可以参照上述图10中的标识。
其中，当在RoF网络系统引入载波调制技术，波分复用(WDM)以及偏振复用技术等时，可以实现多频带、多通信制式信号(基带数字信号，LTE信号，UMTS信号，WIFI信号，毫米波信号等)的共存共传，可以进一步提升中心侧通信设备10在兼容性，接入用户数量，吞入量等方面的表现，但同样会引入光信号传输过程中产生的四波混频，邻波串扰等非线性失 真，据此，下述四个实施例中提供的RoF网络系统的结构也可以对四波混频，邻波串扰等非线性失真进行非线性补偿，具体参照下面实施例中的相关描述。
实施例四
图14为本申请实施例提供的另一实施例的RoF网络系统的结构示意图。如图14所示，本申请实施例中的中心侧通信设备10还可以包括：电域合路器16和电域分路器17。其中，电域合路器16与第一处理装置12连接，电域分路器17与第二处理装置14连接。
本申请实施例中的第一处理装置12，具体用于将子第一基带信号转换为子第一射频信号，且将子第一射频信号输出至电域合路器16。电域合路器16，用于合路N个子第一射频信号，且将合路后的射频信号输出至第一处理装置12。其中，电域合路器16将N个子第一射频信号合路为一路射频信号。相应的，第一处理装置12，具体还用于将合路后的射频信号转换为光信号。
应理解，第一处理装置12将子第一基带信号转换为子第一射频信号的方式，可以参照上述实施例一中第一处理装置12将第一基带信号转换为第一射频信号的方式，且第一处理装置12将合路后的射频信号转换为光信号的方式，可以参照上述实施例一中第一处理装置12将第一射频信号转换为光信号的方式。
本申请实施例中的第二处理装置14，具体用于将第二路光信号转换为第二射频信号，并输出至电域分路器17。电域分路器17，用于将第二射频信号分路为N个子第二射频信号，且将N个子第二射频信号输出至第二处理装置14。应理解，N个子第二射频信号与N个子第一射频信号按照频点一一对应。相应的，第二处理装置14，具体还用于将子第二射频信号转换为子第二基带信号，以得到N个子第二基带信号。
应理解，本申请实施例中，第二处理装置14将第二路光信号转换为第二射频信号的方式，可以参照上述实施例一中第二处理装置14将光信号转换为第二射频信号的方式，且第二处理装置14将子第二射频信号转换为子第二基带信号的方式，可以参照上述实施例一中第二处理装置14将第二射频信号转换为第二基带信号的方式。
图15为本申请实施例提供的另一实施例的RoF网络系统的结构示意图。如图15所示，在一种可能的实现方式中，第一处理模块包括电光转换装置124和N个数模转换装置121，第二处理装置14包括：光电转换装置141和N个模数转换装置144，本振15为N个，且一个本振15对应一个数模转换装置121、一个模数转换装置144。
其中，电域合路器16分别与N个数模转换装置121、电光转换装置124连接，N个数模转换装置121还与非线性补偿装置112连接，每个本振15分别与对应的数模转换装置121、模数转换装置144连接，光分路器13分别电光转换装置124、光电转换装置141连接，电域分路器17分别与光电转换装置141、N个模数转换装置144连接，N个模数转换装置144均与非线性补偿装置112连接。
应理解，本申请实施例中的数模转换装置121，用于将子第一基带信号转换为子第一射频信号，且将子第一射频信号输出至电域合路器16。电光转换装置124，用于将合路后的射频信号转换为光信号。光电转换装置141，用于将第二路光信号转换为第二射频信号，并输出至电域分路器17。模数转换装置144，用于将子第二射频信号转换为子第二基带信号。
可选的，如图15虚线框中所示，第一处理装置12还可以包括：N个第一混频器122、N个带通滤波器123，一个数模转换装置121对应一个第一混频器122、一个带通滤波器123、一个本振15；第二处理装置14还包括：N个第二混频器142和N个低通滤波器143，一个模数转换装置144对应一个第二混频器142、一个低通滤波器143、一个本振15。
其中，每个第一混频器122与对应的数模转换装置121、带通滤波器123和本振15连接，每个带通滤波器123还与电域合路器16连接，每个第二混频器142与对应的低通滤波器143、本振15，以及电域分路器17连接。
在上述的中心侧通信设备10的结构的基础上，可选的，第一处理装置12还包括：N个可调衰减器125、N个低噪声放大器126，一个带通滤波器123对应一个可调衰减器125、一个低噪声放大器126。其中，每个可调衰减器125分别与对应的带通滤波器123、低噪声放大器126连接，N个低噪声放大器126还与电域合路器16连接。
在上述的中心侧通信设备10的结构的基础上，可选的，第一处理装置12还包括：光域放大器127；光域放大器127分别与电光转换装置124、光分路器13连接。
在上述的中心侧通信设备10的结构的基础上，可选的，第二处理装置14还包括：N个电域放大器145，一个电域放大器145对应一个数模转换装置121、一个低通滤波器143，每个电域放大器145与对应的数模转换装置121、低通滤波器143连接。
在本申请实施例提供的中心侧通信设备10的结构的基础上，本申请实施例中的非线性补偿装置112可以根据子第一基带信号，以及与子第一基带信号对应的子第二基带信号，对子第一基带信号进行非线性补偿。
图16为本申请实施例提供的多维DPD非线性补偿的示意图。与上述实施例二中类似的，如图16所示，假设系统的输入信号包括x1(n)、x2(n)……xn(n)，其中，x1(n)、x2(n)……xn(n)均为子第一基带信号，系统的输出信号包括y1(n)、y2(n)……yn(n)，其中，y1(n)、y2(n)……yn(n)均为子第二基带信号。
其中，与上述实施例二中的补偿方法类似的，本申请实施例中还可以采用DPD非线性补偿的方法，但与上述实施例二不同的是，本申请实施例中的第一基带信号包含有多路子第一基带信号，光信号传输过程中产生的四波混频，邻波串扰等非线性失真，因此需要采用多维模型进行DPD非线性补偿。
本实施例中可以与先建立多维模型，且存储在非线性补偿装置112中，该多维模型可以为不限于多项式模型或神经网络模型。其中，该多维模型为根据多路子第一基带信号，以及反馈的多路子第二基带信号建立的。该多维模型除了包含一维模型中包含的信号自身交调项，还包含了多个信号之间的交调项。图17为本申请实施例提供的多频点基带信号之间的交调和串扰表现示意图。如图17所示，图17中横坐标为3个频点的子第一基带信号，纵坐标为信号的功率。该三个频点的子第一基带信号的中线频率分别为200MHz、400MHz和600MHz，三个频点的子第一基带信号在传输的过程中会产生交调和串扰，如图17中所示的实线部分表示的干扰信号。
也就是说，在该种场景下，采用DPD非线性补偿的方法，不仅可以补偿单路基带信号在传输过程中的非线性失真，还能够补偿因为多路基带信号之间的交调和串扰引起的非线性失真。其中，一维模型指的是实施例二中采用的模型。
本申请实施例中的非线性补偿装置112包括：数字预失真模块1121和参数估计模块1122。其中，数字预失真模块1121，用于采用失真参数对子第一基带信号进行预失真处理。参数估计模块1122，用于根据子第一基带信号、子第二基带信号，以及多维模型，更新失真参数，以子第一基带信号进行非线性补偿。应理解，本申请实施例中参数估计模块1122可以根据N个子第一基带信号和与反馈的N个子第二基带信号，以及多维模型，求解得到该更新后的失真参数，以对每个子第一基带信号进行非线性补偿，使得补偿后的子第一基带信号经过第一处理装置12处理得到的光信号不存在非线性失真。应理解，上述多维模型进行DPD非线性补 偿的方式适用于电光转换装置124为EML或DML。
可选的，针对电光转换装置124为EML，本申请实施例中的非线性补偿装置112进行非线性补偿的方法，还可以使用上述实施例三中的补偿方法。相应的，参数估计模块1122，用于根据第子一基带信号和子第二基带信号，获取预设偏置电压与该子一基带信号对应的外部调制器的半波电压之间的差值，进而调整差值，以子第一基带信号进行非线性补偿。
应注意，如图15和图16所示，远端侧通信设备20的结构与上述实施例一中的结构相同，在此不做赘述。
本申请实施例提供的RoF网络系统的结构，在中心侧通信设备中建立反馈链路，能够对单波长多频点的基带信号进行非线性补偿，不仅可以补偿单路基带信号在传输过程中的非线性失真，还能够补偿因为多路基带信号之间的交调和串扰引起的非线性失真。本申请实施例中的其他技术效果可以参照上述实施例二、实施例三的技术效果的相关描述。
实施例五
图18为本申请实施例提供的另一实施例的RoF网络系统的结构示意图。如图18所示，本申请实施例中的中心侧通信设备10还可以包括：电域合路器16、N个电域开关18。其中，电域合路器16与第一处理装置12连接，电域开关18分别与本振15、第二处理装置14连接，一个电域开关18与一个子第一射频信号对应。
本申请实施例中的第一处理装置12，具体用于将子第一基带信号转换为子第一射频信号，且将子第一射频信号输出至电域合路器16。电域合路器16，用于合路N个子第一射频信号，且将合路后的射频信号输出至第一处理装置12。其中，电域合路器16将N个子第一射频信号合路为一路射频信号。相应的，第一处理装置12，具体还用于将合路后的射频信号转换为光信号。应理解，第一处理装置12将子第一基带信号转换为子第一射频信号的方式，以及第一处理装置12将合路后的射频信号转换为光信号的方式，可以参照上述实施例二中的相关描述。
相对应的，本申请实施例中的第二处理装置14，具体用于将第二路光信号转换为第二射频信号。电域开关18，用于控制子第一射频信号对应的子第二射频信号的反馈链路的通断。
应注意的是，电域开关18控制子第二射频信号的反馈链路的通断的一种可能的实现方式可以为：该N个子第一射频信号对应的电域开关18按照预设规则，可以间隔预设时间依次打开且关闭，以控制该电域开关18对应的子第二射频信号的反馈链路导通后，将子第二射频信号反馈给非线性补偿装置112，在将子第二射频信号反馈给非线性补偿装置112后，电域开关18可以关闭，以控制该电域开关18对应的子第二射频信号的反馈链路断开。
示例性的，预设规则可以为每间隔1ms，依次打开子第一射频信号1、子第一射频信号2……子第一射频信号N对应的电域开关18，以使得子第二射频信号1、子第二射频信号2……子第二射频信号N的反馈链路依次导通，进而依次将子第二射频信号1、子第二射频信号2……子第二射频信号N反馈给非线性补偿装置112。
电域开关18控制子第二射频信号的反馈链路的通断的另一种可能的实现方式可以为：电域开关18根据控制指令，以控制该电域开关18对应的子第二射频信号的反馈链路的通断。可选的，控制指令可以为中心侧通信设备10根据上行信号的状态生成的，或者也可以通过人为输入，以控制对应频点的子第二射频信号的反馈链路的通断。
示例性的，若中心侧通信设备10根据接收到的上行信号，确定一频点的上行信号的质量较差，因此可以控制该频点对应的电域开关闭合，以反馈该频点的子第二基带信号，以对该 频点的信号进行非线性补偿，以提高该频点的信号的质量。
电域开关18控制子第二射频信号的反馈链路的通断的另一种可能的实现方式可以为：电域开关18根据上行信号，确定该频点对应的子第二射频信号的反馈链路导通。具体为中心侧通信设备10根据上行信号，确定处于工作状态的频点，进而控制该频点的子第二射频信号的反馈链路导通。
示例性的，如中心侧通信设备10根据上行信号，确定处于工作状态的频点，而其他频点处于非工作状态(休眠状态)，因此，中心侧通信设备10可以控制该工作的频点对应的子第二射频信号的反馈链路导通，以对该处于工作状态的频点的信号进行非线性补偿。
相应的，第二处理装置14，具体还用于将反馈的子第二射频信号转换为子第二基带信号。应理解，第二处理装置14将第二路光信号转换为第二射频信号的方式，以及第二处理装置14将反馈的子第二射频信号转换为子第二基带信号的方式，可以参照上述实施例二中的相关描述。
图19为本申请实施例提供的另一实施例的RoF网络系统的结构示意图。如图19所示，在一种可能的实现方式中，第一处理模块包括电光转换装置124和N个数模转换装置121，第二处理装置14包括：光电转换装置141和模数转换装置144，本振15为N个，且一个本振15对应一个数模转换装置121、一个电域开关18。
其中，电域合路器16分别与N个数模转换装置121、电光转换装置124连接，N个数模转换装置121还与非线性补偿装置112连接，每个本振15与对应的数模转换装置121、电域开关18连接，光分路器13分别与电光转换装置124、光电转换装置141连接，模数转换装置144分别与光电转换装置141、N个电域开关18、非线性补偿装置112连接。
应理解，本申请实施例中的数模转换装置121，用于将子第一基带信号转换为子第一射频信号，且将子第一射频信号输出至电域合路器16。电光转换装置124，用于将合路后的射频信号转换为光信号。光电转换装置141，用于将第二路光信号转换为第二射频信号，且在电域开关18的作用下控制第二射频信号中子第二射频信号的反馈链路的通断。相应的，模数转换装置144，用于将反馈的子第二射频信号转换为子第二基带信号。
可选的，如图19虚线框中所示，第一处理装置12还可以包括：第一处理模块还包括：N个第一混频器122、N个带通滤波器123，一个数模转换装置121对应一个第一混频器122、一个带通滤波器123、一个本振15；第二处理装置14还包括：第二混频器142和低通滤波器143。
其中，每个第一混频器122对应的数模转换装置121、带通滤波器123和本振15连接，每个本振15通过对应的电域开关18与第二混频器142连接，第二混频器142与低通滤波器143连接，低通滤波器143还与模数转换装置144连接。如图所示，电域开关18均与第二混频器142连接。
在上述的中心侧通信设备10的结构的基础上，可选的，第一处理装置12还包括：N个可调衰减器125、N个低噪声放大器126。可调衰减器125、低噪声放大器126的介绍可以参照上述实施例四的相关描述。
在上述的中心侧通信设备10的结构的基础上，可选的，第一处理装置12还包括：光域放大器127。光域放大器127的介绍可以参照上述实施例四的相关描述。
在上述的中心侧通信设备10的结构的基础上，可选的，第二处理装置14还包括：电域放大器145，电域放大器145分别与数模转换装置121、低通滤波器143连接。
应注意，本申请实施例中的非线性补偿装置112的补偿方法可以参照上述实施例四中的 相关描述，在此不做赘述。如图18和图19所示，远端侧通信设备20的结构与上述实施例一中的结构相同，在此不做赘述。
本申请实施例提供的RoF网络系统的结构，在中心侧通信设备中建立反馈链路，能够对单波长多频点的基带信号进行非线性补偿，且在中心侧通信设备中设置电域开关，相较于上述实施例四，可以减少器件重复设置，节省了成本。另本申请实施例中，通过对电域开关的控制，还能够实现对特定频点的基带信号的非线性补偿，选择性更高。本申请实施例中的其他技术效果可以参照上述实施例二、实施例三、实施例四的技术效果的相关描述。
上述实施例四和实施例五提供的RoF网络系统的结构适用于单波长多频点的基带信号，下述实施例六和实施例七提供的RoF网络系统的结构适用于多波长多频点的基带信号。与上述实施例相比较，因为实施例六和实施例七中为多波长的基带信号，因此可以设置波分复用器19和波分解复用器19'对多路光信号进行合路和分路，其中的结构具体见下述实施例六和实施例七。
实施例六
图20为本申请实施例提供的另一实施例的RoF网络系统的结构示意图。如图20所示，本申请实施例中的中心侧通信设备10还可以包括：波分复用器19和波分解复用器19'。其中，波分复用器19分别与第一处理装置12、光分路器13连接，波分解复用器19'分别与光分路器13、第二处理装置14连接。
本申请实施例中的第一处理装置12，具体用于将子第一基带信号转换为子第一射频信号，且将子第一射频信号转换为子第一光信号，以得到N个子第一光信号，光信号包括N个子第一光信号。波分复用器19，用于合路N个子第一光信号，并将合路后的光信号输出至光分路器13，应理解，波分复用器19将N个子第一光信号合路为一路光信号。波分解复用器19'，用于将第二路光信号分路为N个子第二光信号。相应的，第二处理装置14，具体用于将子第二光信号转换为子第二射频信号，且将子第二射频信号转换为子第二基带信号，以得到N个子第二基带信号。
应理解，本申请实施例中的第一处理装置12将子第一基带信号转换为子第一射频信号的方式，将子第一射频信号转换为子第一光信号的方式，以及第二处理装置14将子第二光信号转换为子第二射频信号，以及将子第二射频信号转换为子第二基带信号的方式，可以参照上述实施例一中的相关描述。
图21为本申请实施例提供的另一实施例的RoF网络系统的结构示意图。如图21所示，在一种可能的实现方式中，第一处理模块包括N个数模转换装置121、N个电光转换装置124，一个数模转换装置121对应一个电光转换装置124，第二处理装置14包括：N个光电转换装置141和N个模数转换装置144，一个光电转换装置141对应一个模数转换装置144，本振15为N个，一个本振15对应一个数模转换装置121、一个模数转换装置144。
其中，非线性补偿装置112与N个数模转换装置121连接，每个数模转换装置121与对应的电光转换装置124、本振15连接，波分复用器19分别与N个电光转换装置124、光分路器13连接，波分解复用器19'分别与N个光电转换装置141、光分路器13连接，每个模数转换装置144还与对应的光电转换装置141、本振15连接，N个模数转换装置144均与非线性补偿装置112连接。
数模转换装置121，用于将子第一基带信号转换为子第一射频信号，且将子第一射频信号输出至电光转换装置124。电光转换装置124，用于将子第一射频信号转换为子第一光信号， 且输出至波分复用器19。光电转换装置141，用于将子第二光信号转换为子第二射频信号，并输出至模数转换装置144。模数转换装置144，用于将子第二光信号转换为子第二射频信号，且将子第二射频信号转换为子第二基带信号。
可选的，如图19虚线框中所示，第一处理装置12还可以包括：第一处理模块还包括：N个第一混频器122、N个带通滤波器123，一个数模转换装置121对应一个第一混频器122、一个带通滤波器123、一个本振15；第二处理装置14还包括：N个第二混频器142和N个低通滤波器143，一个模数转换装置144对应一个第二混频器142、一个低通滤波器143、一个本振15。
其中，每个第一混频器122与对应的数模转换装置121、带通滤波器123和本振15连接，每个带通滤波器123还与对应的电光转换装置124连接。每个第二混频器142与对应的低通滤波器143、本振15、光电转换装置141连接。
在上述的中心侧通信设备10的结构的基础上，可选的，第一处理装置12还包括：N个可调衰减器125、N个低噪声放大器126，一个带通滤波器123对应一个可调衰减器125、一个低噪声放大器126、一个电光转换装置124。其中，每个可调衰减器125分别与对应的带通滤波器123、低噪声放大器126连接，每个低噪声放大器126还与对应的电光转换装置124连接。
在上述的中心侧通信设备10的结构的基础上，可选的，第一处理装置12还包括：光域放大器127，光域放大器127分别与波分复用器19、光分路器13连接。
在上述的中心侧通信设备10的结构的基础上，可选的，第二处理装置14还包括：N个电域放大器145，电域放大器145的介绍可以参照上述实施例四的相关描述。
应注意，本申请实施例中的非线性补偿装置112的补偿方法可以参照上述实施例四中的相关描述，在此不做赘述。如图20和图21所示，本申请实施例的远端侧通信设备20中，第三处理装置21包括：波分解复用器19'和N个光电转换装置141，且天线22为N个，一个光电转换装置141对应一个天线22。
其中，波分解复用器19'分别与光分路器13和N个光电转换装置141连接，每个光电转换装置141还与对应的天线22连接。波分解复用器19'，用于将第一路光信号分路为N个子光信号，且输出至对应的光电转换装置141中。光电转换装置141，用于将子光信号转换为子射频信号，且将子射频信号输出至天线22。天线22，用于将子射频信号发射出去。
本申请实施例提供的RoF网络系统的结构，在中心侧通信设备中建立反馈链路，能够对单波长多频点的基带信号进行非线性补偿，不仅可以补偿单路基带信号在传输过程中的非线性失真，还能够补偿因为多路基带信号之间的交调和串扰引起的非线性失真。本申请实施例中的其他技术效果可以参照上述实施例二、实施例三、实施例四和实施例五的技术效果的相关描述。
实施例七
图22为本申请实施例提供的另一实施例的RoF网络系统的结构示意图。如图22所示，本申请实施例中的中心侧通信设备10还可以包括：2N个电域开关18。其中的N个电域开关18设置反馈链路中。
其中，本振15与其中的N个电域开关18连接，N个电域开关18还与第二处理装置14连接，一个电域开关18对应一个子第一射频信号，第二处理装置14还与剩余N个电域开关18连接，一个电域开关18对应一个子第二射频信号，一个子第一射频信号对应一个子第二 射频信号。
本申请实施例中，电域开关18，用于控制子第一射频信号对应的子第二射频信号的反馈链路的通断。其中，电域开关18控制子第二射频信号的反馈链路的通断的方式具体可以参照上述实施例五中的相关描述。相应的，第二处理装置14，具体用于将反馈的子第二射频信号转换为子第二基带信号。
图23为本申请实施例提供的另一实施例的RoF网络系统的结构示意图。如图23所示，在一种可能的实现方式中，第一处理模块包括：N个数模转换装置121、N个电光转换装置124，一个数模转换装置121对应一个电光转换装置124，第二处理装置14包括：N个光电转换装置141和模数转换装置144，一个光电转换装置141对应一个电域开关18，本振15为N个，一个本振15对应一个数模转换装置121、一个电域开关18、一个模数转换装置144。
其中，非线性补偿装置112与N个数模转换装置121连接，每个数模转换装置121与对应的电光转换装置124、本振15连接，每个本振15还与对应的电域开关18连接，波分复用器19分别与N个电光转换装置124、光分路器13连接，波分解复用器19'分别与N个光电转换装置141、光分路器13连接，每个光电转换装置141与对应的电域开关18连接，2N个电域开关18均与模数转换装置144连接，模数转换装置144还与非线性补偿装置112连接。
数模转换装置121，用于将子第一基带信号转换为子第一射频信号，且将子第一射频信号输出至电光转换装置124。电光转换装置124，用于子第一射频信号转换为子第一光信号，且输出至波分复用器19。光电转换装置141，用于将子第二光信号转换为子第二射频信号。电域开关18，用于控制子第二射频信号的通断。模数转换装置144，用于将反馈的子第二射频信号转换为子第二基带信号。
可选的，如图23虚线框中所示，第一处理装置12还可以包括：N个第一混频器122、N个带通滤波器123，一个数模转换装置121对应一个第一混频器122、一个带通滤波器123、一个本振15；第二处理装置14还包括：第二混频器142和低通滤波器143。其中，其中，每个第一混频器122与对应的数模转换装置121、带通滤波器123和本振15连接，每个本振15通过对应的电域开关18与第二混频器142连接，每个带通滤波器123还与对应的电光转换装置124连接。
第二混频器142还与对应的低通滤波器143连接，低通滤波器143还与模数转换装置144连接连接，且剩余的N个电域开关均与第二混频器142连接。
在上述的中心侧通信设备10的结构的基础上，可选的，第一处理装置12还包括：N个可调衰减器125、N个低噪声放大器126，一个带通滤波器123对应一个可调衰减器125、一个低噪声放大器126、一个电光转换装置124。可调衰减器125和低噪声放大器126的介绍可以参照上述实施例六的相关描述。
在上述的中心侧通信设备10的结构的基础上，可选的，第一处理装置12还包括：光域放大器127，光域放大器127的介绍可以参照上述实施例六的相关描述。
在上述的中心侧通信设备10的结构的基础上，可选的，第二处理装置14还包括：N个电域放大器145，电域放大器145的介绍可以参照上述实施例四的相关描述。
应注意，本申请实施例中的非线性补偿装置112的补偿方法可以参照上述实施例四中的相关描述，在此不做赘述。如图22和图23所示，本申请实施例的远端侧通信设备20的结构可以参照上述实施例六的相关描述。
本申请实施例提供的RoF网络系统的结构，在中心侧通信设备中建立反馈链路，能够对单波长多频点的基带信号进行非线性补偿，不仅可以补偿单路基带信号在传输过程中的非线 性失真，还能够补偿因为多路基带信号之间的交调和串扰引起的非线性失真。且在中心侧通信设备中设置电域开关，相较于上述实施例六，可以减少器件重复设置，节省了成本。另本申请实施例中，通过对电域开关的控制，还能够实现对特定频点的基带信号的非线性补偿，选择性更高。本申请实施例中的其他技术效果可以参照上述实施例二、实施例三、实施例四、实施例五和实施例六的技术效果的相关描述。
本申请实施例还提供一种通信系统，如图9、图10、图12、图14-图15、图18-图23中所示，该通信系统包括中心侧通信设备和至少一个远端侧通信设备。其中，远端侧通信设备包括天线。远端侧通信设备，用于将来自中心侧通信设备的第一路光信号转换为射频信号，且将射频信号通过天线发射。应理解，本申请实施例中的中心侧通信设备和远端侧通信设备的结构具体见上述实施例一至实施例七中的相关描述。

Claims (21)

  1. 一种通信设备，其特征在于，包括：数字处理装置、第一处理装置、光分路器、第二处理装置和本振，所述第一处理装置分别与所述数字处理装置、所述本振、所述光分路器连接，所述光分路器还与所述第二处理装置连接，所述第二处理装置还与所述本振、所述数字处理装置连接；
    所述数字处理装置，用于生成第一基带信号，且将所述第一基带信号输出至所述第一处理装置；
    所述第一处理装置，用于将所述第一基带信号转换为第一射频信号，且将所述第一射频信号转换为光信号，以及将所述光信号输出至所述光分路器；
    所述光分路器，用于将所述光信号分路为第一路光信号和第二路光信号，且将所述第一路光信号输出至至少一个远端通信设备，将所述第二路光信号输出至所述第二处理装置；
    所述第二处理装置，用于将所述第二路光信号转换为第二射频信号，且将所述第二射频信号转换为第二基带信号，以及将所述第二基带信号输出至所述数字处理装置；
    所述数字处理装置，还用于根据所述第一基带信号和所述第二基带信号，对所述第一基带信号进行非线性补偿。
  2. 根据权利要求1所述的通信设备，其特征在于，所述第一基带信号包括N个子第一基带信号，所述第二基带信号包括N个子第二基带信号，所述第一射频信号包括N个子第一射频信号，所述第二射频信号包括N个子第二射频信号，所述子第一射频信号与所述子第二射频信号按照频点一一对应，N为大于或等于1的整数；
    所述数字处理装置包括：基带资源池和非线性补偿装置，所述基带资源池和所述非线性补偿装置连接，所述非线性补偿装置还分别与所述第一处理装置、所述第二处理装置连接；
    所述基带资源池，用于生成所述N个子第一基带信号，且将所述N个子第一基带信号经由所述非线性补偿装置输出至所述第一处理装置；
    所述第一处理装置，具体用于将所述子第一基带信号转换为所述子第一射频信号，且将所述N个子第一射频信号转换为所述光信号；
    所述第二处理装置，具体用于将所述第二路光信号转换为所述N个子第二射频信号，且将所述子第二射频信号转换为所述子第二基带信号；
    所述非线性补偿装置，用于根据所述子第一基带信号，以及与所述子第一基带信号对应的子第二基带信号，对所述子第一基带信号进行非线性补偿。
  3. 根据权利要求2所述的通信设备，其特征在于，所述光信号的波长为1310nm。
  4. 根据权利要求2或3所述的通信设备，其特征在于，当所述N大于1时，所述通信设备还包括电域合路器，所述电域合路器与所述第一处理装置连接；
    所述第一处理装置，具体还用于将所述子第一射频信号输出至所述电域合路器；
    所述电域合路器，用于合路N个子第一射频信号，且将合路后的射频信号输出至所述第一处理装置；
    所述第一处理装置，具体还用于将所述合路后的射频信号转换为所述光信号。
  5. 根据权利要求4所述的通信设备，其特征在于，所述通信设备还包括电域分路器，所述电域分路器与所述第二处理装置连接；
    所述第二处理装置，具体还用于将所述第二射频信号输出至所述电域分路器；
    所述电域分路器，用于将所述第二射频信号分路为N个子第二射频信号，且将N个子第二 射频信号输出至第二处理装置。
  6. 根据权利要求5所述的通信设备，其特征在于，所述第一处理模块包括电光转换装置和N个数模转换装置，所述第二处理装置包括：光电转换装置和N个模数转换装置，所述本振为N个，且一个本振对应一个数模转换装置、一个模数转换装置；
    所述电域合路器分别与所述N个数模转换装置、所述电光转换装置连接，所述N个数模转换装置还与所述非线性补偿装置连接，每个本振分别与对应的数模转换装置、模数转换装置连接，所述光分路器分别所述电光转换装置、所述光电转换装置连接，所述电域分路器分别与所述光电转换装置、所述N个模数转换装置连接，所述N个模数转换装置均与所述非线性补偿装置连接。
  7. 根据权利要求4所述的通信设备，其特征在于，所述通信设备还包括N个电域开关，所述电域开关分别与所述本振、所述第二处理装置连接，一个电域开关对应一个子第一射频信号；
    电域开关，用于控制子第一射频信号对应的子第二射频信号的反馈链路的通断；
    所述第二处理装置，具体还用于将反馈的子第二射频信号转换为子第二基带信号。
  8. 根据权利要求7所述的通信设备，其特征在于，所述第一处理模块包括电光转换装置和N个数模转换装置，所述第二处理装置包括：光电转换装置和模数转换装置，所述本振为N个，且一个本振对应一个数模转换装置、一个电域开关；
    所述电域合路器分别与所述N个数模转换装置、所述电光转换装置连接，所述N个数模转换装置还与所述非线性补偿装置连接，每个本振与对应的数模转换装置、电域开关连接，所述光分路器分别与所述电光转换装置、所述光电转换装置连接，所述模数转换装置分别与所述光电转换装置、所述N个电域开关、所述非线性补偿装置连接。
  9. 根据权利要求2或3所述的通信设备，其特征在于，当所述N大于1时，所述通信设备还包括波分复用器和波分解复用器，所述波分复用器分别与所述第一处理装置、所述光分路器连接，所述波分解复用器分别与所述光分路器、所述第二处理装置连接；
    所述第一处理装置，具体用于将所述子第一射频信号转换为子第一光信号，以得到N个子第一光信号，所述光信号包括所述N个子第一光信号；
    所述波分复用器，用于合路所述N个子第一光信号，并将合路后的光信号输出至所述光分路器；
    所述波分解复用器，用于将所述第二路光信号分路为N个子第二光信号；
    所述第二处理装置，具体还用于将所述子第二光信号转换为子第二射频信号，且将所述子第二射频信号转换为所述子第二基带信号，以得到所述N个子第二基带信号。
  10. 根据权利要求9所述的通信设备，其特征在于，所述第一处理模块包括N个数模转换装置、N个电光转换装置，一个数模转换装置对应一个电光转换装置，所述第二处理装置包括：N个光电转换装置和N个模数转换装置，一个光电转换装置对应一个模数转换装置，所述本振为N个，一个本振对应一个数模转换装置、一个模数转换装置；
    所述非线性补偿装置与所述N个数模转换装置连接，每个数模转换装置与对应的电光转换装置、本振连接，所述波分复用器分别与所述N个电光转换装置、所述光分路器连接，所述波分解复用器分别与所述N个光电转换装置、所述光分路器连接，每个模数转换装置还与对应的光电转换装置、本振连接，所述N个模数转换装置均与所述非线性补偿装置连接。
  11. 根据权利要求9所述的通信设备，其特征在于，所述通信设备还包括：2N个电域开关，所述本振与其中的N个电域开关连接，所述N个电域开关还与第二处理装置连接，一个电 域开关对应一个子第一射频信号，所述第二处理装置还与剩余N个电域开关连接，一个电域开关对应一个子第二射频信号，一个子第一射频信号对应一个子第二射频信号；
    电域开关，用于控制子第一射频信号对应的子第二射频信号的反馈链路的通断；
    所述第二处理装置，具体还用于将反馈的子第二射频信号转换为子第二基带信号。
  12. 根据权利要求11所述的通信设备，其特征在于，所述第一处理模块包括N个数模转换装置、N个电光转换装置，一个数模转换装置对应一个电光转换装置，所述第二处理装置包括：N个光电转换装置和模数转换装置，一个光电转换装置对应一个电域开关，所述本振为N个，一个本振对应一个数模转换装置、一个电域开关、一个模数转换装置；
    所述非线性补偿装置与所述N个数模转换装置连接，每个数模转换装置与对应的电光转换装置、本振连接，每个本振还与对应的电域开关连接，所述波分复用器分别与N个电光转换装置、所述光分路器连接，所述波分解复用器分别与所述N个光电转换装置、所述光分路器连接，每个光电转换装置与对应的电域开关连接，所述2N个电域开关均与所述模数转换装置连接，所述模数转换装置还与所述非线性补偿装置连接。
  13. 根据权利要求6、8、10或12所述的通信设备，其特征在于，所述第一处理模块还包括：N个第一混频器、N个带通滤波器，一个数模转换装置对应一个第一混频器、一个带通滤波器、一个本振；当所述第二处理装置包括N个模数转换装置时，所述第二处理装置还包括：N个第二混频器和N个低通滤波器，一个模数转换装置对应一个第二混频器、一个低通滤波器、一个本振；
    每个第一混频器与对应的数模转换装置、带通滤波器、本振连接，每个带通滤波器还与电域合路器或者对应的电光转换装置连接；
    每个第二混频器与对应的低通滤波器、本振连接，每个第二混频器还与电域分路器或对应的光电转换装置连接。
  14. 根据权利要求6、8、10或12所述的通信设备，其特征在于，所述第一处理模块还包括：N个第一混频器、N个带通滤波器，一个数模转换装置对应一个第一混频器、一个带通滤波器、一个本振；当所述第二处理装置包括一个模数转换装置时，所述第二处理装置还包括：第二混频器和低通滤波器；
    每个第一混频器与对应的数模转换装置、带通滤波器、本振连接，每个本振通过对应的电域开关与所述第二混频器连接，每个带通滤波器还与所述电域合路器或者对应的电光转换装置连接；
    所述第二混频器与所述低通滤波器连接，所述低通滤波器还与模数转换装置连接，且电域开关均与所述第二混频器连接。
  15. 根据权利要求13或14所述的通信设备，其特征在于，所述第一处理装置还包括：N个可调衰减器、N个低噪声放大器，一个带通滤波器对应一个可调衰减器、一个低噪声放大器；
    每个可调衰减器分别与对应的带通滤波器、低噪声放大器连接，N个低噪声放大器还与所述电域合路器连接。
  16. 根据权利要求15所述的通信设备，其特征在于，所述第一处理装置还包括：光域放大器；
    所述光域放大器分别与所述电光转换装置、所述光分路器连接。
  17. 根据权利要求13或14所述的通信设备，其特征在于，所述第一处理装置还包括：N个可调衰减器、N个低噪声放大器，一个带通滤波器对应一个可调衰减器、一个低噪声放 大器、一个电光转换装置；
    每个可调衰减器分别与对应的带通滤波器、低噪声放大器连接，每个低噪声放大器还与对应的电光转换装置连接。
  18. 根据权利要求17所述的通信设备，其特征在于，所述第一处理装置还包括：光域放大器；
    所述光域放大器分别与波分复用器、所述光分路器连接。
  19. 根据权利要求6、8、10或12所述的通信设备，其特征在于，所述电光转换装置为外部调制器或直接调制器，所述非线性补偿装置包括：数字预失真模块和参数估计模块；
    所述数字预失真模块，用于采用失真参数对所述第一基带信号进行预失真处理；
    所述参数估计模块，用于根据所述第一基带信号和所述第二基带信号，更新所述失真参数，以对所述第一基带信号进行非线性补偿。
  20. 根据权利要求6、8、10或12所述的通信设备，其特征在于，所述电光转换装置为外部调制器，所述非线性补偿装置包括：数字预失真模块和参数估计模块；
    所述数字预失真模块，用于采用失真参数对所述第一基带信号进行预失真处理；
    所述参数估计模块，用于根据所述第一基带信号和所述第二基带信号，获取预设偏置电压与所述外部调制器的半波电压之间的差值；
    根据所述差值，更新所述失真参数，以对所述第一基带信号进行非线性补偿。
  21. 一种通信系统，其特征在于，包括：如上述权利要求1-20任一项所述的通信设备，以及至少一个远端侧通信设备，所述远端侧通信设备包括天线；
    所述远端侧通信设备，用于将来自中心侧通信设备的第一路光信号转换为射频信号，且将所述射频信号通过天线发射。
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