CN113726445A - Modulation signal generation method and terahertz wireless transmission method and system - Google Patents
Modulation signal generation method and terahertz wireless transmission method and system Download PDFInfo
- Publication number
- CN113726445A CN113726445A CN202110782669.0A CN202110782669A CN113726445A CN 113726445 A CN113726445 A CN 113726445A CN 202110782669 A CN202110782669 A CN 202110782669A CN 113726445 A CN113726445 A CN 113726445A
- Authority
- CN
- China
- Prior art keywords
- signal
- terahertz
- modulation signal
- band
- wireless transmission
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- 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
- H04B10/50—Transmitters
- H04B10/516—Details of coding or modulation
- H04B10/54—Intensity modulation
- H04B10/541—Digital intensity or amplitude modulation
-
- 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
- H04B10/50—Transmitters
- H04B10/501—Structural aspects
- H04B10/503—Laser transmitters
-
- 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
- H04B10/50—Transmitters
- H04B10/516—Details of coding or modulation
- H04B10/548—Phase or frequency modulation
- H04B10/556—Digital modulation, e.g. differential phase shift keying [DPSK] or frequency shift keying [FSK]
- H04B10/5561—Digital phase modulation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optics & Photonics (AREA)
- Optical Communication System (AREA)
Abstract
The invention relates to a modulation signal generation method, a terahertz wireless transmission method and a terahertz wireless transmission system. The modulation signal generation method comprises the following steps: distributing sub-bands for each user data, and carrying out amplitude modulation on each user data to obtain a real number signal; obtaining a sub-band modulation signal based on each real signal; and obtaining a multi-band modulation signal according to each sub-band modulation signal. According to the modulation signal generation method, the sub-bands are distributed to the user data, and the data in the sub-bands are subjected to amplitude modulation, so that the plurality of user data can be transmitted in the same channel at different rates, the frequency spectrum efficiency and the transmission capacity are improved, and the multi-user data distribution is more flexible.
Description
Technical Field
The invention relates to the technical field of wireless transmission, in particular to a modulation signal generation method, a terahertz wireless transmission method and a terahertz wireless transmission system.
Background
In order to meet the requirements of mobile data services for higher transmission rate and larger transmission capacity, the terahertz (0.1THz-10THz) frequency band attracts a great deal of research interest in recent years with large bandwidth and high frequency. In order to further reduce the cost and simplify the system, a terahertz wireless transmission system based on Intensity Modulation (IM) and Direct Detection (DD) is widely researched, and compared with a coherent detection scheme, the system has lower complexity and cost. A terahertz wireless transmission system based on IM/DD and combined with an advanced modulation format and a digital signal processing technology (DSP) is an effective scheme for realizing multi-user access. In recent years, advanced high-order coded modulation techniques have been widely used to improve spectral efficiency. The IEEE P802.3bs 400GbE working group adopts PAM-4 as an industrial standard, and the DSP structure is simpler and the energy consumption is lower due to the digital signal processing technology; discrete Multi-Tone modulation (DMT) has strong recovery capability for optical fiber dispersion and high spectral efficiency, and is also widely used. However, Pulse Amplitude Modulation (PAM) and discrete multi-tone Modulation cannot achieve multi-user access through a simple IM/DD scheme, often at a huge power consumption and cost penalty.
Therefore, in the field of the terahertz wireless transmission system based on the IM/DD, an efficient transmission scheme which can realize multi-user access and is low in cost does not exist yet.
Disclosure of Invention
In view of the above, it is necessary to provide a modulation signal generation method and a terahertz wireless transmission method and system.
A modulation signal generation method, comprising: distributing sub-bands for each user data, and carrying out amplitude modulation on each user data to obtain a real number signal; obtaining a sub-band modulation signal based on each real signal; and obtaining a multi-band modulation signal according to each sub-band modulation signal.
According to the modulation signal generation method, the sub-bands are distributed to the user data, and the data in the sub-bands are subjected to amplitude modulation, so that the plurality of user data can be transmitted in the same channel at different rates, the frequency spectrum efficiency and the transmission capacity are improved, and the multi-user data distribution is more flexible.
The modulation signal generation method further includes: carrying out digital signal processing operation on the multi-band modulation signal to obtain a digital multi-band modulation signal; and performing digital-to-analog conversion on the digital multi-band modulation signal to obtain an analog multi-band modulation signal.
In one embodiment, the digital signal processing operation comprises: a resampling operation and/or a normalization operation.
A terahertz wireless transmission method comprises the following steps: according to the modulation signal generation method in any one of the above embodiments, a multiband modulation signal is generated based on each of the user data; loading the multi-band modulation signal to a terahertz carrier wave to obtain an optical signal; transmitting the optical signal by a wired transmission mode; and obtaining a transmission signal with terahertz carrier frequency according to the optical signal, and transmitting the transmission signal in a wireless transmission mode.
In one embodiment, the method for generating the terahertz carrier wave comprises the following steps: generating a first optical carrier and a second optical carrier, wherein the frequency difference between the first optical carrier and the second optical carrier is terahertz; and coupling the first optical carrier and the second optical carrier to obtain the terahertz carrier.
In one embodiment, the obtaining a transmission signal with a carrier frequency of terahertz according to the optical signal includes: and carrying out beat frequency on the optical signal to obtain the transmission signal.
A terahertz wireless transmission method comprises the following steps: receiving a transmission signal, wherein the transmission signal is transmitted by adopting the terahertz wireless transmission method in any embodiment; demodulating the transmission signal into user data.
In one embodiment, demodulating the transmission signal into user data includes: recovering the transmission signal into a multi-band modulation signal by adopting an envelope detection method; and demodulating and restoring the multi-band modulation signal into the user data.
In one embodiment, before demodulating and restoring the multi-band modulated signal to the user data, the method further includes: and performing analog-to-digital conversion on the multi-band modulation signal.
A terahertz wireless transmission system comprising: the data processing device is used for distributing sub-bands for each user data and carrying out amplitude modulation on each user data to obtain a real number signal; obtaining a sub-band modulation signal based on each real signal; obtaining a multi-band modulation signal according to each sub-band modulation signal, loading the multi-band modulation signal on a terahertz carrier to obtain an optical signal, and transmitting the optical signal in a wired transmission mode; and the baseband unit is connected with the data processing device in a wired mode and used for receiving the optical signal, obtaining a transmission signal with terahertz carrier frequency according to the optical signal and transmitting the transmission signal in a wireless transmission mode.
In one embodiment, the data processing apparatus includes: a multi-band signal generating module for generating the multi-band modulated signal; and the waveform generator is connected with the multi-band signal generating module and used for carrying out digital-to-analog conversion on the multi-band modulation signal so as to obtain an analog multi-band modulation signal.
In one embodiment, the data processing apparatus further comprises an electrical amplifier connected to the waveform generator for amplifying the analog multi-band modulated signal.
In one embodiment, the data processing apparatus further comprises: the carrier generation module is used for generating the terahertz carrier; and the intensity modulator is connected with the electrical amplifier and the carrier generation module and is used for loading the multi-band modulation signal onto the terahertz carrier to obtain the optical signal.
In one embodiment, the baseband unit includes: a first receiving module for receiving the optical signal; the conversion module is connected with the receiving module and used for converting the multi-band modulation signal into a terahertz wave signal with terahertz carrier frequency; and the transmitting module is connected with the converting module and is used for transmitting the terahertz wave signal.
The application also discloses terahertz wireless transmission system includes: the terminal is used for receiving the terahertz wave signal and demodulating the terahertz wave signal to obtain user data; wherein, the transmission signal is transmitted by the terahertz wireless transmission system in any one of the above embodiments.
In one embodiment, the terminal includes: the second receiving module is used for receiving the terahertz wave signal; an envelope detector for demodulating the terahertz wave signal into a multiband modulation signal; the analog-to-digital conversion module is used for performing analog-to-digital conversion on the multi-band modulation signal to obtain a digital multi-band modulation signal; and the demodulation module is used for demodulating and restoring the digital multi-band modulation signal into the user data.
According to the terahertz wireless transmission method and the terahertz wireless transmission system, sub-band allocation and amplitude modulation are combined, on one hand, data transmission can be performed facing multiple users, multiple user data are transmitted in the same channel at different rates, the frequency spectrum efficiency and the transmission capacity are improved, and the multi-user data allocation is more flexible; on the other hand, the difficulty of signal modulation is reduced, and the system cost is reduced.
Drawings
Fig. 1 is a flowchart of a modulation signal generating method according to an embodiment of the present application.
Fig. 2 is a flowchart of a terahertz wireless transmission method according to an embodiment of the present application.
Fig. 3 is a block flow diagram of a terahertz wireless transmission method according to another embodiment of the present application.
Fig. 4 is a block diagram of a terahertz wireless transmission system according to an embodiment of the present application.
Fig. 5 is a block diagram of a data processing apparatus according to an embodiment of the present application.
Fig. 6 is a block diagram of a signal generation module according to an embodiment of the present application.
Fig. 7 is a block diagram of a data processing apparatus according to another embodiment of the present application.
Fig. 8 is a block diagram of a data processing apparatus according to another embodiment of the present application.
Fig. 9 is a block diagram of a terahertz wireless transmission system according to another embodiment of the present application.
Fig. 10 is a block diagram of a terahertz wireless transmission system according to another embodiment of the present application.
Fig. 11 is a block diagram of a demodulation module according to an embodiment of the present application.
Fig. 12 is a block diagram of a terahertz wireless transmission system according to still another embodiment of the present application.
Fig. 13 is a schematic diagram illustrating a transmission process of user data in a terahertz wireless transmission system according to an embodiment of the present application.
Fig. 14 is a graph of the ber of each sub-band with the received optical power according to an embodiment of the present application.
Fig. 15 is a diagram illustrating a comparison of frequency spectrums between a multi-band CAP-PAM modulation signal obtained by a modulation signal generation method according to an embodiment of the present application and a conventional single-band CAP-PAM modulation signal.
Fig. 16 is a frequency spectrum comparison graph of a multi-band CAP-PAM modulated signal recovered based on a terahertz wireless transmission method and a single-band CAP-PAM modulated signal obtained by using a conventional demodulation method in an embodiment of the present application.
The reference numbers illustrate: 1. a data processing device; 11. a multi-band signal generating module; 111. a PAM mapping module; 112. an upsampling module; 113. forming a filtering module; 12. a waveform generator; 13. an electrical amplifier; 14. a carrier generation module; 141. a first semiconductor laser; 142. a second semiconductor laser; 143. an optical coupler; 15. an intensity modulator; 16. an optical fiber; 2. a baseband unit; 21. a first receiving module; 22. a conversion module; 23. a power amplifier; 24. a transmitting module; 3. a terminal; 31. a second receiving module; 32. an envelope detector; 33. an analog-to-digital conversion module; 34. a demodulation module; 341. a clock synchronization module; 342. a matched filtering module; 343. a down-sampling module; 344. an adaptive filtering module; 345. and a PAM demapping module.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
In describing positional relationships, unless otherwise specified, when an element such as a layer, film or substrate is referred to as being "on" another layer, it can be directly on the other layer or intervening layers may also be present. Further, when a layer is referred to as being "under" another layer, it can be directly under, or one or more intervening layers may also be present. It will also be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.
Where the terms "comprising," "having," and "including" are used herein, another element may be added unless an explicit limitation is used, such as "only," "consisting of … …," etc. Unless mentioned to the contrary, terms in the singular may include the plural and are not to be construed as being one in number.
As shown in fig. 1, one embodiment of the present application provides a modulated signal generating method, which includes the steps of:
s11: and allocating a subband for each user data, and carrying out amplitude modulation on each user data to obtain a real number signal.
The user data refers to data to be transmitted corresponding to each user. As an example, different subbands (sub-bands) may be allocated to each user data based on a multiband carrierless amplitude-phase modulation technique (CAP), and the rate of each subband may be different, so that multiple user data may be transmitted in the same channel at different rates, respectively, thereby improving the spectrum efficiency and transmission capacity of the system, and enabling multi-user allocation to be more flexible.
Meanwhile, the modulation signal generation method also performs amplitude modulation on the user data in each subband to obtain a real signal. For example, the user data may be N-order PAM encoded, alternatively N may be any integer, such as 2, 3, 4, 5, 6 or 7. The PAM modulation is used as a one-dimensional modulation format, can directly carry out intensity modulation, is easy to realize in a real domain, and has lower calculation complexity and flexible realization compared with the traditional quadrature amplitude modulation (QAM modulation), so that the system structure is simpler.
As an example, the number of subbands may be 4, and PAM modulation performed for each subband may be PAM-5, PAM-3, PAM-2, and PAM-2, respectively.
S13: a subband modulation signal is derived based on each of the real signals.
After obtaining the real signals, each real signal is up-sampled to obtain up-sampled real signals. And then, performing forming filtering on the up-sampling real number signal to obtain a sub-band modulation signal. The upsampling is also called as upsampling or interpolating, and the sampling rate of the signal obtained by upsampling is greater than that of the original signal. The shaping filtering can reduce the intersymbol interference, reduce the bandwidth and improve the utilization rate of the frequency band. As an example, the number of upsamples of the signal may be 4.
S15: and obtaining a multi-band modulation signal according to each sub-band modulation signal.
Specifically, the respective subband modulation signals are added to obtain a multi-band modulation signal. The modulation process simultaneously uses the CAP modulation and PAM modulation principles, so that the obtained multi-band modulation signal can be called a multi-band CAP-PAM modulation signal.
In one embodiment, on the basis of the above embodiment, the step of the modulated signal generating method may further include:
s17: and carrying out digital signal processing operation on the multi-band modulation signal to obtain a digital multi-band modulation signal.
Specifically, the digital signal processing operation on the multiband modulation signal includes resampling and/or normalization operation, so as to obtain a digital multiband modulation signal, so as to perform subsequent digital-to-analog conversion processing.
S19: and performing digital-to-analog conversion on the digital multi-band modulation signal to obtain an analog multi-band modulation signal.
As an example, an arbitrary waveform generator may be used to perform digital-to-analog conversion on the digital multi-band modulated signal to generate an analog multi-band modulated signal. Optionally, after generating the analog multi-band modulation signal, the analog multi-band modulation signal may be amplified by using an electrical amplifier.
According to the modulation signal generation method, the sub-bands are distributed to the user data, and the data in the sub-bands are subjected to amplitude modulation, so that the plurality of user data can be transmitted in the same channel at different rates, the frequency spectrum efficiency and the transmission capacity are improved, and the multi-user data distribution is more flexible.
An embodiment of the present application further provides a terahertz wireless transmission method, as shown in fig. 2, the terahertz wireless transmission method includes:
s21: according to the modulation signal generation method in any one of the foregoing embodiments, a multiband modulation signal is generated based on each user data.
In the modulation signal generation method in the foregoing example, by performing subband allocation and amplitude modulation on user data and ingeniously combining the principles of CAP modulation and PAM modulation, multiple user data can be transmitted in the same channel at different rates, so that user data allocation is more flexible and data transmission spectrum efficiency is higher.
S23: and loading the multi-band modulation signal to a terahertz carrier wave to obtain an optical signal.
Specifically, the terahertz optical carrier is formed by coupling two optical carriers with different wavelengths by an optical coupler. As an example, the two optical carriers of different wavelengths may include a first optical carrier and a second optical carrier, wherein a frequency difference between the first optical carrier and the second optical carrier is terahertz, for example, the frequency difference may be 101GHz, 103GHz, 105GHz, and 107 GHz. In this embodiment, the first optical carrier and the second optical carrier may be emitted by two separate external cavity semiconductor lasers.
After the terahertz optical carrier is obtained, the terahertz optical carrier and the multi-band modulation signal are jointly input into the intensity modulator, the multi-band modulation signal is used as a driving signal of the intensity modulator, the terahertz optical carrier is modulated, and the multi-band modulation signal is loaded to the terahertz optical carrier to obtain an optical signal.
Optionally, before the multi-band modulated signal is input to the intensity modulator, the method further includes performing amplification processing on the multi-band modulated signal.
S25: and transmitting the optical signal by a wired transmission mode.
Specifically, the optical signals can be transmitted to a base station or a signal transfer station of a user terminal accessory through optical fibers in a long distance, and then the optical signals are processed to obtain a signal form suitable for wireless transmission. As an example, optical signals may be transmitted to the baseband unit using optical fibers.
S27: and obtaining a transmission signal with terahertz carrier frequency according to the optical signal, and transmitting the transmission signal in a wireless transmission mode.
Specifically, heterodyne technology may be adopted to perform beat frequency on the optical signal, so as to obtain a transmission signal with a carrier frequency of terahertz. And sending the transmission signal to a transmitting antenna for wireless transmission. The principle of the heterodyne technique is to generate a new frequency by mixing two signals with different frequencies in wireless signal processing.
As an example, after the optical signal is subjected to beat frequency, a terahertz wave signal with a terahertz carrier frequency is obtained, and then the terahertz wave signal is amplified by a terahertz waveband power amplifier and sent to a transmitting antenna for wireless transmission.
According to the terahertz wireless transmission method, the multi-band CAP-PAM format is combined with the terahertz wireless transmission system for the first time, multi-line rate and low-cost transmission for multi-user data are achieved, the frequency spectrum efficiency and the transmission capacity of the system can be improved, multi-user allocation is more flexible, and the safety and the reliability of multi-user access data transmission are guaranteed.
Another embodiment of the present application further discloses a terahertz wireless transmission method, as shown in fig. 3, the terahertz wireless transmission method includes:
s31: receiving a transmission signal, wherein the transmission signal is transmitted by adopting the terahertz wireless transmission method in any one of the embodiments.
As an example, when the transmission signal is a terahertz wave signal whose carrier frequency is terahertz, the user terminal may receive the transmission signal using a terahertz band receiving antenna.
S33: demodulating the transmission signal into user data.
Specifically, for a received terahertz wave signal, the user terminal may first perform power adjustment, and then perform square-law detection on the terahertz wave signal by using an envelope detection method, so as to recover the multi-band modulation signal. And finally, the user terminal performs analog-to-digital conversion on the recovered multi-band modulation signal, demodulates and restores the multi-band modulation signal to obtain an original data stream, and completes transmission of a plurality of user data.
According to the terahertz wireless transmission method, after the transmission signal carrying the user data is received, the multi-band modulation signal is recovered by adopting a direct detection method of envelope detection, and compared with the traditional coherent detection scheme, the system cost is greatly reduced.
An embodiment of the present application further discloses a terahertz wireless transmission system, as shown in fig. 4, the terahertz wireless transmission system includes: a data processing device 1 and a baseband unit 2. The data processing device 1 is configured to allocate subbands to each user data, and perform amplitude modulation on each user data to obtain a real number signal; obtaining a sub-band modulation signal based on each real number signal; obtaining a multi-band modulation signal according to each sub-band modulation signal, loading the multi-band modulation signal on a terahertz carrier to obtain an optical signal, and transmitting the optical signal in a wired transmission mode; the baseband unit 2 is connected with the data processing device 1 by wire, and the baseband unit 2 is configured to receive an optical signal, obtain a transmission signal with a terahertz carrier frequency according to the optical signal, and transmit the transmission signal in a wireless transmission manner.
According to the terahertz wireless transmission system, the sub-bands are distributed to the user data, and the data in the sub-bands are subjected to amplitude modulation, so that the user data can be transmitted in the same channel at different rates, the system spectrum efficiency and the transmission capacity are improved, and the multi-user data is distributed more flexibly.
In one embodiment, as shown in fig. 5, the data processing apparatus 1 includes a multi-band signal generation module 11 and a waveform generator 12. The multi-band signal generating module 11 is configured to generate a multi-band modulation signal, and the waveform generator 12 is configured to perform digital-to-analog conversion on the multi-band modulation signal. As an example, the waveform generator 12 may be an arbitrary waveform generator. Specifically, the multi-band signal generating module 11 allocates sub-bands to each user data after receiving a plurality of user data. The user data refers to data to be transmitted corresponding to each user. As an example, the multi-band signal generating module 11 allocates different sub-bands to each user data by using a multi-band carrierless amplitude-phase modulation (CAP), and the rate of each sub-band may be different, so that multiple user data are transmitted in the same channel by using different rates, respectively, the spectrum efficiency and the transmission capacity of the system are improved, and the flexibility of user data allocation is improved.
For the user data allocated to each subband, the multi-band signal generating module 11 performs amplitude modulation, upsampling, and shaping filtering on the user data to obtain a subband modulation signal. In one embodiment, as shown in fig. 6, the multi-band signal generation module 11 may include a PAM mapping module 111, an upsampling module 112, and a shaping filtering module 113. The PAM mapping module 111 may perform N-order PAM coding on the user data of each subband, thereby obtaining a real signal. The PAM modulation is used as a one-dimensional modulation format, can directly carry out intensity modulation, is easy to realize in a real domain, and has lower calculation complexity and flexible realization compared with the traditional quadrature amplitude modulation (QAM modulation), so that the system structure is simpler.
The upsampling module 112 is connected to the PAM mapping model 111, and is configured to upsample the real signal to obtain an upsampled real signal. The frequency of the up-sampled real signal matches the sampling frequency of the waveform generator 12. The number of up-sampled samples may be determined by the symbol rate and the sampling frequency of the waveform generator 12. The shaping filtering module 113 is connected to the upsampling module 112, and configured to perform shaping filtering on the upsampled real number signal to obtain each subband modulation signal. Finally, the sub-band modulation signals are added to obtain the multi-band modulation signal. The up-sampling real number signal is shaped and filtered by the shaped filtering module 113, so that intersymbol interference can be reduced, the bandwidth can be reduced, and the frequency band utilization rate can be improved.
After the multi-band modulation signal is obtained, the multi-band modulation signal is transmitted to the waveform generator 12 for digital-to-analog conversion to obtain an analog multi-band modulation signal, so that the analog multi-band modulation signal is loaded into a carrier for data transmission.
According to the terahertz wireless transmission system, the CAP modulation technology and the PAM modulation technology are combined, the multi-band modulation signal (multi-band CAP-PAM signal) is obtained after user data are processed, the situation that a plurality of user data are transmitted in the same channel at different rates can be achieved, the system frequency spectrum efficiency and the transmission capacity are improved, and multi-user distribution is more flexible.
In one embodiment, as shown in fig. 7, the data processing device 1 further comprises an electrical amplifier 13, the electrical amplifier 13 being connected to the waveform generator 12 for amplifying the analog multi-band modulated signal.
In one embodiment, as shown in fig. 8, the data processing apparatus 1 further includes a carrier generation module 14 and an intensity modulator 15. The carrier generation module 14 is configured to generate a terahertz carrier; the intensity modulator 15 is connected to the electrical amplifier 13 and the carrier generation module 14, and the intensity modulator 15 is configured to load the multiband modulation signal onto the terahertz carrier to obtain an optical signal.
Specifically, the analog multiband modulation signal is amplified and then transmitted to the intensity modulator 15 as a driving signal of the intensity modulator 15 to modulate the terahertz carrier wave. Wherein, the terahertz carrier is generated by the carrier generation module 14. The carrier generation block 14 includes two semiconductor lasers and an optical coupler. The two semiconductor lasers provide two optical carriers with different wavelengths, the frequency difference between the optical carriers is terahertz, for example 101GHz, and the frequency difference between the two optical carriers can also be 103GHz, 105GHz or 107GHz, etc. The two optical carriers are combined into one by an optical coupler and then input to the intensity modulator 15, and modulated by an analog multi-band modulation signal to obtain an optical signal containing carrier and data information, where the optical signal may be transmitted to the baseband unit 2 through an optical fiber, for example, the optical signal may be transmitted through a single-mode optical fiber. By way of example, the intensity modulator 15 may be a mach-zehnder intensity modulator, the semiconductor laser may be an external-cavity semiconductor laser, and the optical coupler may be a polarization-controlled coupler.
In one embodiment, as shown in fig. 9, the baseband unit 2 in the terahertz wireless transmission system includes: a first receiving module 21, configured to receive an optical signal; the conversion module 22 is connected with the receiving module, and the conversion module 22 is used for converting the multi-band modulation signal into a transmission signal with terahertz carrier frequency; and a transmitting module 24 connected to the converting module 22, wherein the transmitting module 24 is configured to transmit the transmission signal. As an example, the transmission signal may be a terahertz wave signal whose carrier frequency is terahertz.
Specifically, the optical signal is transmitted from the data processing apparatus 1 to the baseband unit 2 via the optical fiber, and then received by the first receiving module 21. As an example, the first receiving module 21 may be a variable optical attenuator. The variable optical attenuator, upon receiving the optical signal, adjusts its power to effect a sensitivity measurement. Then, the optical signal with the power adjusted is sent to the conversion module 22, and the multi-band modulation signal is converted into a terahertz wave signal with a carrier frequency of terahertz. Specifically, the conversion module 22 may be a photodiode, and performs beat frequency on the optical signal by using a heterodyne technique to obtain a multiband terahertz wave signal with a carrier frequency of terahertz. The transmitting module 24 is connected to the converting module 22 and can be used for transmitting a terahertz wave signal to realize wireless transmission of the signal. As an example, the transmission module 24 may be a terahertz-band transmission antenna.
In one embodiment, the baseband unit 2 further comprises a power amplifier. The terahertz wave signal is amplified by a power amplifier before being transmitted by the terahertz wave band transmitting antenna. In particular, the power amplifier may be a terahertz-band power amplifier.
As shown in fig. 10, the present application further discloses a terahertz wireless transmission system, which includes a terminal 3, where the terminal 3 is configured to receive a transmission signal and demodulate the transmission signal to obtain user data; the transmission signal is transmitted by the terahertz wireless transmission system in any one of the embodiments.
Specifically, the terminal 3 may include: a second receiving module 31, configured to receive a transmission signal; an envelope detector 32 for demodulating the transmission signal into a multiband modulated signal; the analog-to-digital conversion module 33 is configured to perform analog-to-digital conversion on the multi-band modulation signal to obtain a digital multi-band modulation signal; and a demodulation module 34, configured to demodulate and restore the digital multi-band modulated signal into user data.
Specifically, taking the transmission signal as a terahertz wave as an example, the second receiving module 31 may be a terahertz-band receiving antenna. After receiving the terahertz wave signal from the baseband unit 2, the second receiving module 31 transmits the terahertz wave signal to the power amplifier for power adjustment, and then sends the terahertz wave signal to the envelope detector 32 for square-law detection, so as to recover the multi-band modulation signal. The recovered multi-band modulation signal is amplified by the electrical amplifier and then transmitted to the analog-to-digital conversion module 33 to perform analog-to-digital conversion on the multi-band modulation signal, so as to obtain a digital multi-band modulation signal. By way of example, the analog-to-digital conversion module 33 may be a real-time digital storage oscilloscope, and the demodulation module 34 may be a multi-band signal demodulation module. The demodulation module 34 is connected to the analog-to-digital conversion module 33 to demodulate the digital multi-band modulation signal and obtain the original data stream.
In one embodiment, as shown in fig. 11, the demodulation module 34 includes: a clock synchronization module 341, a matched filtering module 342, a downsampling module 343, an adaptive filtering module 344, and a PAM demapping module 345. The clock synchronization module 341 is configured to perform synchronization processing on the multi-band modulation signal output by the analog-to-digital conversion module 33, so as to implement bit frame synchronization and select an optimal decision point; a matched filter module 342, configured to separate each branch signal of the multi-band modulation signal; a down-sampling module 343, configured to perform down-sampling on each branch signal to match the sampling rate of the oscilloscope; the adaptive filtering module 344 is used for compensating signal nonlinear damage and high-frequency attenuation and optimizing performance; a PAM demapping module 345 for recovering the original binary data sequence.
In one embodiment, the wireless terahertz transmission system in the embodiment shown in fig. 9 and the wireless terahertz transmission system in the embodiment shown in fig. 10 together form a new wireless terahertz transmission system, as shown in fig. 12. The specific limitations of each sub-module can be referred to the above description of the embodiments shown in fig. 9 and fig. 10, and are not repeated here.
In one embodiment, the transmission process of user data in a terahertz wireless transmission system is shown in fig. 13. The terahertz wireless transmission system in this embodiment specifically includes: data processing apparatus 1, optical fiber 16, baseband unit 2 and terminal 3. In particular, the data processing device 1 may be a central station, the optical fiber 16 may be a single mode optical fiber, and the terminal 3 may be a subscriber terminal.
As an example, the central station is connected to the baseband unit 2 via a 1km long optical fiber 16, and a 101GHz terahertz multiband CAP-PAM terahertz wave signal output by the baseband unit 2 is transmitted by a transmitting antenna and received by an antenna of a user terminal after 2m wireless transmission.
In this embodiment, the central station includes: a multiband signal generation module 11, a waveform generator 12, an electric amplifier 13, a first semiconductor laser 141, a second semiconductor laser 142, an optical coupler 143, and an intensity modulator 15. The first semiconductor laser 141 and the second semiconductor laser 142 are external cavity semiconductor lasers, the waveform generator 12 is an arbitrary waveform generator, and the optical coupler 143 is a polarization control coupler.
Specifically, the optical coupler 143 is connected to an input terminal of the intensity modulator 15, and an output terminal of the intensity modulator 15 is connected to the baseband unit 2 through the optical fiber 16. The multi-band signal generation module 11, the waveform generator 12, the electric amplifier 13 and the driving signal input end of the intensity modulator 15 are connected in sequence.
Specifically, at the central station, after the user data is input into the multi-band signal generating module 11, the multi-band CAP-PAM modulation signal is obtained by using the modulation signal generating method in any of the foregoing embodiments. As an example, the number of subbands may be 4, and PAM modulation performed for each subband may be PAM-5, PAM-3, PAM-2, and PAM-2, respectively. The multi-band CAP-PAM modulated signal is sent to an arbitrary waveform generator for digital-to-analog conversion, and amplified by an electrical amplifier 13 to be used as a driving signal of an intensity modulator 15. Two light carriers with different wavelengths provided by the external cavity semiconductor laser are combined into one by the optical coupler 143 to obtain a light carrier group, the light carrier group is modulated by a multi-band CAP-PAM modulation signal in the intensity modulator 15 to obtain a light signal containing data information, and the light signal is transmitted to the baseband unit 2 through the optical fiber 16.
In this embodiment, the frequency difference between two optical carriers with frequencies f _ c1 and f _ c2 as the optical carrier group is 101 GHz; the length of the used optical fiber 16 is 1 km; the bias voltage of the intensity modulator 15 is set to 3.6V, and the amplitude of the output signal of the multi-band signal generating module 11 is set to 200 mV.
In this embodiment, the baseband unit 2 includes: a first receiving module 21, configured to receive an optical signal; the conversion module 22 is connected with the receiving module, and the conversion module 22 is used for converting the multi-band modulation signal into a transmission signal with terahertz carrier frequency; a power amplifier 23 for amplifying power of the transmission signal; and a transmitting module 24 connected to the power amplifier 23, wherein the transmitting module 24 is configured to transmit the transmission signal.
The first receiving module 21 is a variable optical attenuator, the converting module 22 is a photodiode, the power amplifier 23 is a terahertz band power amplifier, and the transmitting module 24 is a terahertz band transmitting antenna.
Specifically, in the baseband unit 2, the variable optical attenuator receives the optical signal transmitted through the optical fiber 16 and adjusts its power; a heterodyne technology is adopted to beat frequency of optical signals in a photodiode, multi-band CAP-PAM terahertz wave signals with terahertz carrier frequencies are generated, and the signals are amplified by a terahertz wave band power amplifier and then sent to a terahertz wave band transmitting antenna for transmission. Wherein the generated terahertz wave signal is a multi-band CAP-PAM terahertz wave signal of 101 GHz;
in this embodiment, the terminal 3 includes: a second receiving module 31, configured to receive a transmission signal; an envelope detector 32 for demodulating the transmission signal into a multiband modulated signal; the analog-to-digital conversion module 33 is configured to perform analog-to-digital conversion on the multi-band modulation signal to obtain a digital multi-band modulation signal; and a demodulation module 34, configured to demodulate and restore the digital multi-band modulated signal into user data.
The second receiving module 31 is a terahertz band receiving antenna, the analog-to-digital conversion module 33 is a real-time digital storage oscilloscope, and the demodulation module 34 is a multi-band signal demodulation module.
Specifically, at the user terminal, the terahertz band receiving antenna receives a 101GHz multiband CAP-PAM terahertz wave signal wirelessly transmitted from the baseband unit 2, the power of the signal is adjusted by the power amplifier 23 and then sent to the envelope detector 32 for square-law detection, so that recovery of a multiband CAP-PAM modulation signal is realized, the recovered multiband CAP-PAM signal is amplified by the electric amplifier 13, data capture and analog-to-digital conversion are realized by the real-time digital storage oscilloscope, and an original data stream is obtained by reduction after demodulation by the multiband signal demodulation module, so that multi-user data transmission is completed.
Data transmission tests were performed based on the above-described terahertz wireless transmission system, and some of the test results are shown in fig. 14 to 16. Fig. 14 is a curve of the bit error rate of each sub-band varying with the received optical power in this embodiment, and a test result shows that the multi-user bit error rate is lower than the bit error threshold, so that multi-line rate and low-cost transmission for multi-user data are realized. Fig. 15 is a diagram showing a comparison of frequency spectrums between a multi-band CAP-PAM modulation signal obtained based on a modulation signal generation method and a conventional single-band CAP-PAM modulation signal in this embodiment, and fig. 16 is a diagram showing a comparison of frequency spectrums between a multi-band CAP-PAM modulation signal recovered based on a terahertz wireless transmission method and a single-band CAP-PAM modulation signal obtained by using a conventional demodulation method in this embodiment. Compared with the scheme of the traditional wireless transmission system, the terahertz wireless transmission system has the advantages of simple structure, flexible multi-user spectrum allocation, low calculation complexity, low transmission cost and the like, and has wide prospects in the technical field of terahertz wireless transmission.
The steps of a method or algorithm described in connection with the disclosure herein may be embodied in hardware or in software instructions executed by a processor. The software instructions may be comprised of corresponding software modules that may be stored in Random Access Memory (RAM), flash Memory, Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), registers, a hard disk, a removable disk, a compact disc Read Only Memory (CD-ROM), or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. Of course, the storage medium may also be integral to the processor.
Those skilled in the art will recognize that in one or more of the examples described above, the functions described herein may be implemented in hardware, software, firmware, or any combination thereof. When implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (16)
1. A method for generating a modulated signal, comprising:
distributing sub-bands for each user data, and carrying out amplitude modulation on each user data to obtain a real number signal;
obtaining a sub-band modulation signal based on each real signal;
and obtaining a multi-band modulation signal according to each sub-band modulation signal.
2. The modulation signal generation method according to claim 1, characterized by further comprising:
carrying out digital signal processing operation on the multi-band modulation signal to obtain a digital multi-band modulation signal;
and performing digital-to-analog conversion on the digital multi-band modulation signal to obtain an analog multi-band modulation signal.
3. The modulated signal generating method of claim 2, wherein the digital signal processing operation comprises: a resampling operation and/or a normalization operation.
4. A terahertz wireless transmission method is characterized by comprising the following steps:
the modulation signal generation method according to claim 1 or 2, generating a multi-band modulation signal based on each of the user data;
loading the multi-band modulation signal to a terahertz carrier wave to obtain an optical signal;
transmitting the optical signal by wire transmission
And obtaining a transmission signal with terahertz carrier frequency according to the optical signal, and transmitting the transmission signal in a wireless transmission mode.
5. The terahertz wireless transmission method according to claim 4, wherein the method of generating the terahertz carrier wave comprises:
generating a first optical carrier and a second optical carrier, wherein the frequency difference between the first optical carrier and the second optical carrier is terahertz;
and coupling the first optical carrier and the second optical carrier to obtain the terahertz carrier.
6. The terahertz wireless transmission method according to claim 4, wherein the obtaining of the transmission signal with the carrier frequency terahertz from the optical signal comprises:
and carrying out beat frequency on the optical signal to obtain the transmission signal.
7. A terahertz wireless transmission method is characterized by comprising the following steps:
receiving a transmission signal transmitted by the terahertz wireless transmission method according to any one of claims 4 to 6;
demodulating the transmission signal into user data.
8. The terahertz wireless transmission method according to claim 7, wherein the demodulating the transmission signal into user data includes:
recovering the transmission signal into a multi-band modulation signal by adopting an envelope detection method;
and demodulating and restoring the multi-band modulation signal into the user data.
9. The thz wireless transmission method according to claim 8, wherein before demodulating and restoring the multiband modulated signal into the user data, the method further comprises:
and performing analog-to-digital conversion on the multi-band modulation signal.
10. A terahertz wireless transmission system, comprising:
the data processing device is used for distributing sub-bands for each user data and carrying out amplitude modulation on each user data to obtain a real number signal; obtaining a sub-band modulation signal based on each real signal; obtaining a multi-band modulation signal according to each sub-band modulation signal, loading the multi-band modulation signal on a terahertz carrier to obtain an optical signal, and transmitting the optical signal in a wired transmission mode;
and the baseband unit is connected with the data processing device in a wired mode and used for receiving the optical signal, obtaining a transmission signal with terahertz carrier frequency according to the optical signal and transmitting the transmission signal in a wireless transmission mode.
11. The terahertz wireless transmission system according to claim 10, wherein the data processing apparatus includes:
a multi-band signal generating module for generating the multi-band modulated signal;
and the waveform generator is connected with the multi-band signal generating module and used for carrying out digital-to-analog conversion on the multi-band modulation signal so as to obtain an analog multi-band modulation signal.
12. The terahertz wireless transmission system according to claim 11, wherein the data processing apparatus further comprises:
and the electric amplifier is connected with the waveform generator and is used for amplifying the analog multi-band modulation signal.
13. The terahertz wireless transmission system according to claim 12, wherein the data processing apparatus further comprises:
the carrier generation module is used for generating the terahertz carrier;
and the intensity modulator is connected with the electrical amplifier and the carrier generation module and is used for loading the multi-band modulation signal onto the terahertz carrier to obtain the optical signal.
14. The terahertz wireless transmission system according to any one of claims 10 to 13, wherein the baseband unit includes:
a first receiving module for receiving the optical signal;
the conversion module is connected with the receiving module and used for converting the multi-band modulation signal into the transmission signal with terahertz carrier frequency;
and the transmitting module is connected with the converting module and is used for transmitting the transmission signal.
15. A terahertz wireless transmission system is characterized by comprising:
the terminal is used for receiving the transmission signal and demodulating the transmission signal to obtain user data;
the terahertz wireless transmission system comprises a terahertz wireless transmission system and a terahertz wireless transmission system, wherein the terahertz wireless transmission system is used for transmitting the transmission signal.
16. The terahertz wireless transmission system according to claim 15, wherein the terminal comprises:
a second receiving module, configured to receive the transmission signal;
an envelope detector for demodulating the transmission signal into a multi-band modulated signal;
the analog-to-digital conversion module is used for performing analog-to-digital conversion on the multi-band modulation signal to obtain a digital multi-band modulation signal;
and the demodulation module is used for demodulating and restoring the digital multi-band modulation signal into the user data.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110782669.0A CN113726445B (en) | 2021-07-12 | 2021-07-12 | Modulation signal generation method and terahertz wireless transmission method and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110782669.0A CN113726445B (en) | 2021-07-12 | 2021-07-12 | Modulation signal generation method and terahertz wireless transmission method and system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113726445A true CN113726445A (en) | 2021-11-30 |
| CN113726445B CN113726445B (en) | 2022-11-18 |
Family
ID=78673193
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110782669.0A Active CN113726445B (en) | 2021-07-12 | 2021-07-12 | Modulation signal generation method and terahertz wireless transmission method and system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113726445B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997027550A2 (en) * | 1996-01-24 | 1997-07-31 | Adc Telecommunications, Inc. | Communication system with multicarrier telephony transport |
| US20090175365A1 (en) * | 2005-12-01 | 2009-07-09 | Jun Yong Ii | Modulation and demodulation apparatuses and methods for wired/wireless communication system |
| US20110110674A1 (en) * | 2008-04-15 | 2011-05-12 | Deutsche Telekom Ag | Method and device for processing terahertz waves |
| CN105450577A (en) * | 2015-12-03 | 2016-03-30 | 东南大学 | Filter bank multi-carrier visible light communication system and method based on DC (Direct Current) bias |
| CN108599864A (en) * | 2018-03-06 | 2018-09-28 | 东南大学 | A kind of incoherent optical transmission multiple access system based on wide sub-filter group |
| CN112532325A (en) * | 2020-11-25 | 2021-03-19 | 浙江大学 | Multi-dimensional multiplexing photon terahertz communication system |
| CN112564819A (en) * | 2020-12-11 | 2021-03-26 | 浙江大学 | Photoelectric terahertz high-speed communication system with direct detection function |
-
2021
- 2021-07-12 CN CN202110782669.0A patent/CN113726445B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997027550A2 (en) * | 1996-01-24 | 1997-07-31 | Adc Telecommunications, Inc. | Communication system with multicarrier telephony transport |
| US20090175365A1 (en) * | 2005-12-01 | 2009-07-09 | Jun Yong Ii | Modulation and demodulation apparatuses and methods for wired/wireless communication system |
| US20110110674A1 (en) * | 2008-04-15 | 2011-05-12 | Deutsche Telekom Ag | Method and device for processing terahertz waves |
| CN105450577A (en) * | 2015-12-03 | 2016-03-30 | 东南大学 | Filter bank multi-carrier visible light communication system and method based on DC (Direct Current) bias |
| CN108599864A (en) * | 2018-03-06 | 2018-09-28 | 东南大学 | A kind of incoherent optical transmission multiple access system based on wide sub-filter group |
| CN112532325A (en) * | 2020-11-25 | 2021-03-19 | 浙江大学 | Multi-dimensional multiplexing photon terahertz communication system |
| CN112564819A (en) * | 2020-12-11 | 2021-03-26 | 浙江大学 | Photoelectric terahertz high-speed communication system with direct detection function |
Non-Patent Citations (2)
| Title |
|---|
| WEIJUN GAO: "Distance-Adaptive Absorption Peak Modulation (DA-APM) for Terahertz Covert Communications", 《IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS(VOLUME:20,ISSUE:3）》 * |
| 王凯辉等: "多频带的D波段毫米波通信", 《太赫兹科学与电子信息学报》 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113726445B (en) | 2022-11-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110995404B (en) | Terahertz secret communication system based on chaotic encryption | |
| CN109067468B (en) | KK transmission method applied to direct detection optical communication system and direct detection optical communication system | |
| CN110350982A (en) | One kind is from coherent signal receiving/transmission method and device | |
| CN111541492A (en) | Multichannel expanded ultra-wideband radio-frequency channelized receiving device and implementation method | |
| CN113382318B (en) | Method and apparatus for optical communication | |
| CN105933070A (en) | Radio-frequency signal transmitting system, receiving system, transmitting-receiving system and transmitting-receiving method | |
| CN116155385A (en) | Multicarrier modulation scheme based on orthogonal chirp multiplexing signal reconstruction under KK relation | |
| CN113114375A (en) | Photon terahertz communication method and device | |
| CN113726445B (en) | Modulation signal generation method and terahertz wireless transmission method and system | |
| CN116582182B (en) | digital-DSM-optical fiber radio DD-RoF method | |
| CN110505016B (en) | Electric vector millimeter wave generation method based on push-pull modulator | |
| CN101562482B (en) | Fiber wireless communication system and method for generating downlink multi-service millimeter wave | |
| CN113645171A (en) | Reconfigurable intelligent surface multi-user MIMO system modulation and demodulation method and device | |
| CN101136705B (en) | Full optical subcarrier demodulator and method of millimeter wave optical fiber radio uplink | |
| CN108599864B (en) | Incoherent optical communication multiple access system based on broadband filter bank | |
| Cordeiro et al. | All-digital transmitter with RoF remote radio head | |
| CN112804007B (en) | Dual-signal modulation and demodulation method and device for radio-over-fiber communication system | |
| US11381202B2 (en) | Envelope-detecting circuit and receiver incorporating this circuit | |
| CN107592158B (en) | The method and apparatus of signal processing in optical fiber telecommunications system | |
| CN111224720B (en) | Terahertz vector signal generation system and method of cascade connection of dual-intensity modulator | |
| CN114430298A (en) | Multi-system compatible space laser communication method and system based on direct modulation | |
| Bhogal et al. | Performance investigation Of CPFSK integrated with OFDM in inter-satellite OWC system | |
| WO2024007118A1 (en) | Terahertz communication method that improves transmission rate | |
| CN113890629B (en) | Terahertz signal receiving device and method and signal transmission system | |
| CN116582183B (en) | Digital modulation optical fiber radio method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |