CN105634540B - Radio frequency system applied to co-channel full duplex system simultaneously - Google Patents
Radio frequency system applied to co-channel full duplex system simultaneously Download PDFInfo
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- CN105634540B CN105634540B CN201610018729.0A CN201610018729A CN105634540B CN 105634540 B CN105634540 B CN 105634540B CN 201610018729 A CN201610018729 A CN 201610018729A CN 105634540 B CN105634540 B CN 105634540B
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- signal
- full duplex
- channel full
- adjustable optical
- radio frequency
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
- H04B1/50—Circuits using different frequencies for the two directions of communication
- H04B1/52—Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa
- H04B1/525—Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa with means for reducing leakage of transmitter signal into the receiver
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/14—Two-way operation using the same type of signal, i.e. duplex
Abstract
The present invention provides a kind of radio frequency systems applied to co-channel full duplex system simultaneously, comprising: directly modulates laser, adjustable optical delay line, adjustable optical attenuator, balanced reciver；The upper branch of straight modulation laser is connected to the first input end of balanced reciver, and directly the lower branch of modulation laser passes sequentially through adjustable optical attenuator, adjustable optical delay line is connected to the second input terminal of balanced reciver；Adjustable optical delay line passes through time delay caused by different paths for matching self-interference signal；Adjustable optical attenuator is used to match the amplitude size of self-interference signal；Balanced reciver carries out subtraction for receiving branch, lower branch two ways of optical signals on straight modulation laser, is converted into corresponding electric signal output after obtaining useful optical signal.The present invention cuts down self-interference signal using inexpensive direct modulation laser modulation radiofrequency signal, and by balanced reciver, and good interference elimination performance and rejection are obtained in wider band limits.
Description
Technical field
The present invention relates to communication and wireless communication technology fields, and in particular, to one kind is applied to co-channel full duplex simultaneously
The radio frequency system of system.
Background technique
With the continuous application of novel internet of things service and big data business in mobile communication system, user is to wireless
The demand of communications system transmission capacity sharply increases, and in order to adapt to the rapid growth demand of mobile Internet business, meets user
Requirement to the following new business, future broadband wireless communication systems need to have the transmittability of superelevation rate, big density network access
Scale, the local operation of real time implementation and ubiquitous broadband access ability etc..In terms of Radio Transmission Technology, in order to meet future
The mobile communication business and user bandwidth demand that exponentially increases further excavate frequency spectrum resource, improve spectrum efficiency as prominent
It goes wrong.Spectrum efficiency is promoted, i.e. exploitation higher order modulation format, this generally requires very high cost.The anxiety of frequency spectrum resource
Mean that the cost for increasing available bandwidth is also very high.For the radio spectrum resources for more efficiently utilizing growing tension, the next generation is moved
Dynamic communication system proposes new demand to wireless full-duplex technology.With existing frequency division duplex (Frequency-Division
Duplex, FDD) or time division duplex (Time-Division Duplex, TDD) system is compared, while co-channel full duplex system
The real time bidirectional communication between user is realized on the same frequency channels, theoretically spectrum efficiency can double, to realize
Big density, efficient network insertion.On the other hand, existing wireless communications application mainly works in low-frequency range, develops higher
The radio band of frequency is a kind of effective dilatation means.In the case where at present using frequency spectrum resource shortage, using same simultaneously
Channel full duplex technology, and realize that full-duplex communication will become the weight of future broadband wireless communication systems in the microwave frequency band of higher frequency
It selects.
While co-channel full duplex wireless communication system will not need FDD or tdd mode and be separately separated on frequency domain or time domain
Uplink and downlink channel can satisfy and operate at the same frequency in synchronization dual-mode antenna, realize real time bidirectional wireless communication.
Due to transmitting antenna and receiving antenna close, the powerful transmitting signal geographically of co-channel full duplex system simultaneously
It can be received antenna reception, self-interference, i.e., co-located interference are generated to the same UHF band reception signal of weak power.Self-interference effect meeting
The quality for receiving signal is seriously affected, useful signal will be buried in self-interference signal and can not be detected, to restrict
The realization of co-channel full duplex technology simultaneously is a big Pinch technology of full duplex communication system development.Therefore, it realizes simultaneously with frequency
The matter of utmost importance of full duplex communication system is exactly to eliminate to same frequency self-interference.Self-interference based on electronics scheme eliminates system
System bandwidth of operation, working frequency range and elimination performance are limited by electronic component performance.Based on optical self-interference technology for eliminating
The advantage of optical technology is applied in system, can support the electric signal of higher frequency section at area of light
Reason, thus realize system to the extension of high band, under high-transmission bandwidth carry out self-interference elimination.It is existing to be based on
In the self-interference technology for eliminating of optical plan, usually using wideband modulators such as MZ Mach-Zehnder, electroabsorption modulators
Electric signal is modulated.Interference signal part is subtracted from the signal received using the characteristic of optical device, is obtained faint
Useful reception signal.This process needs to replicate the transmitting signal of own system, and carries out reverse phase, delay and decaying to it with to the greatest extent
Amount eliminates the self-interference signal received in signal.
It is found by literature search, John Suarez et al. is in " IEEE JOURNAL OF QUANTUM
ELECTRONICS (Institute of Electrical and Electric Engineers Quantum Electronics magazine) " delivered on (April, 2009) it is entitled
“Incoherent Method of Optical Interference Cancellation for Radio-Frequency
The article of Communications " has been put forward for the first time optics self-interference cancellation scheme.The program utilizes double parallel mach zhender
The positive slope adjustment curve and negative slope adjustment curve of modulator are modulated with two MZ Mach-Zehnders respectively and to be received
The transmitting signal of signal and duplication, wherein the optical signal of negative slope adjustment curve branch carries out necessary decaying and delay, two-way
Enter photodetector after signal is coupled to detect.This scheme obtains the self-interference signal of opposite electricity scheme higher frequency band
It eliminates, is reported in the inhibition ratio for obtaining 73dB at the single-frequency point of 3GHz frequency range in document.Not due to two-way modulator coherence
It is good, and the drift of adjustment curve has an impact to performance, so that self-interference is eliminated bandwidth is not very greatly, 3GHz frequency to be reported in document
It can get the inhibition ratio of 33dB in section 96MHz bandwidth.
Find that M.P.Chang, M.Fok et al. are in 2013 in " IEEE Microwave and through retrieval again
Wireless Components Letters (Institute of Electrical and Electric Engineers microwave and wireless element flash report) " (Vol.23,
No.2,2013) entitled " Optical analog self-interference cancellation using has been delivered on
The article of electro-absorption modulators ".The program has used two electroabsorption modulators (EAM) with will be electric
In signal modulation to light carrier, the useful signal and interference signal that wherein EAM1 modulation receives, the transmitting of the modulation duplication of EAM 2
Signal.The signal modulated is coupled through upper and lower two branch optic path and in balanced reciver respectively, is carried out to two paths of signals
Subtraction and convert optical signals to electric signal.Wherein inferior division optical path is decayed and is delayed to signal, to match simultaneously
Eliminate the interference signal in top set's optical path.Decaying and delay require accurately to adjust to obtain maximized interference suppression ratio.
Experiment obtain 25dB in 400MHz bandwidth and inhibit be more than in ratio and 40MHz narrow bandwidth 30dB inhibition ratio.The program by
It is limited to the modulation bandwidth of electroabsorption modulator, still there is the space of development and utilization for the frequency spectrum resource of higher frequency section.
Summary of the invention
For the defects in the prior art, the object of the present invention is to provide a kind of applied to co-channel full duplex system simultaneously
Radio frequency system.
What is provided according to the present invention is applied to the radio frequency system of co-channel full duplex system simultaneously, comprising: straight
Connect modulation laser, adjustable optical delay line, adjustable optical attenuator, balanced reciver；The upper branch of the straight modulation laser connects
It is connected to the first input end of balanced reciver, the lower branch of the straight modulation laser passes sequentially through adjustable optical attenuator, adjustable
Optical delay line is connected to the second input terminal of balanced reciver；Wherein,
The straight modulation laser includes the first RF signal input end mouth, the second RF signal input end mouth, and described the
One RF signal input end mouth is used to receive by the useful signal that receives of receiving antenna of co-channel full duplex system simultaneously and oneself
Interference signal；The second RF signal input end mouth receives the hair of co-channel full duplex system transmitting antenna while duplication obtains
Penetrate signal；
The adjustable optical delay line passes through time delay caused by different paths for matching self-interference signal；
The adjustable optical attenuator is used to match the amplitude size of self-interference signal；
The balanced reciver carries out subtraction for receiving branch, lower branch two ways of optical signals on straight modulation laser
Operation is converted into corresponding electric signal output after obtaining useful optical signal.
It preferably, further include single mode optical fiber, the upper branch of the straight modulation laser is connected to balance by single mode optical fiber
The first input end of receiver.
Preferably, radio frequency system configures the receiving antenna, transmitting antenna of co-channel full duplex system at the same time
Rear class.
Preferably, the transmitting signal of co-channel full duplex system transmitting antenna refers to while duplication obtains: from simultaneously with frequency
The transmitting signal that the transmitting antenna front end of full duplex system is replicated.
It preferably, further include optical receiving device, the electric signal of the optical receiving device receiving balance receiver output, demodulation
The useful radiofrequency signal after self-interference is eliminated out.
Compared with prior art, the present invention have it is following the utility model has the advantages that
1, the radio frequency system provided by the invention for being applied to co-channel full duplex system simultaneously, passes through low cost
Directly modulated lasers can obtain comparable interference suppression ratio wirelessly communicating in common frequency range, obtained in super large bandwidth range
Preferable interference suppressioning effect.
2, the tunable optical provided by the invention being applied in the radio frequency system of co-channel full duplex system simultaneously
Delay line and attenuator have played the high-precision advantage of optical device, more accurately adjust inferior division road optical signal amplitude and
Time delay is to match the amplitude and phase of interference signal.
3, the broadband provided by the invention for being applied to the radio frequency system of co-channel full duplex system simultaneously inhibits
It works well, compared to the performance in document, the present invention can get the inhibition ratio for being greater than 27dB in 6GHz bandwidth, in 400MHz bandwidth
It inside can get the inhibition ratio greater than 40dB and 33dB at 900MHz and 2.4GHz frequency range respectively.
Detailed description of the invention
Upon reading the detailed description of non-limiting embodiments with reference to the following drawings, other feature of the invention,
Objects and advantages will become more apparent upon:
The structural schematic diagram of co-channel full duplex system while Fig. 1 is present invention application；In Fig. 1, Tx indicates transmitting antenna,
Rx indicates receiving antenna；
Fig. 2 is the radio frequency system structural representation provided by the invention for being applied to co-channel full duplex system simultaneously
Figure；
When Fig. 3 is in 900MHz frequency range 400MHz bandwidth, system of the invention inhibits ratio and frequency
Relation curve schematic diagram；
When Fig. 4 is in 2.4GHz frequency range 400MHz bandwidth, system of the invention inhibits ratio and frequency
Relation curve schematic diagram；
When Fig. 5 is in 0-6GHz bandwidth, system of the invention inhibits to show than the relation curve with frequency
It is intended to.
Specific embodiment
The present invention is described in detail combined with specific embodiments below.Following embodiment will be helpful to the technology of this field
Personnel further understand the present invention, but the invention is not limited in any way.It should be pointed out that the ordinary skill of this field
For personnel, without departing from the inventive concept of the premise, various modifications and improvements can be made.These belong to the present invention
Protection scope.
The radio frequency system provided by the invention for being applied to co-channel full duplex system simultaneously, makes interference signal exist
Obtain the inhibition ratio for being greater than 40dB and 33dB in 400MHz bandwidth range at 900MHz and 2.4GHz frequency range respectively.Make self-interference
Signal can obtain in 0-6GHz bandwidth is greater than 27dB inhibition ratio, good to broadband signal and high band self-interference signal to realize
Good elimination, recovers faint useful signal from high reject signal.
According to the present invention on one side, the radio frequency being applied in co-channel full duplex wireless communication system simultaneously provided is certainly dry
Disturb elimination system, including directly modulated lasers, adjustable optical delay line, adjustable optical attenuator, single mode optical fiber and balanced reciver etc..
Wherein, the prevention at radio-frequency port 1 of the directly modulated lasers inputs the useful signal received and interference signal, directly modulated lasers radio-frequency head
The transmitting signal of 2 input duplication of mouth.
The adjustable optical attenuator is used to match the amplitude size of interference signal；The adjustable optical delay line is dry for matching
Disturb the time delay that signal is generated by different paths；The common purpose of the two is the self-interference for making the transmitting signal of duplication and receiving
Signal amplitude is equal, phase alignment, reach best eradicating efficacy.The balanced reciver is for receiving two-way light
Signal and subtraction is carried out to it, then obtained optical signal is converted into electric signal, obtain final useful signal.
Specifically, as shown in Figure 1, in the present embodiment, provide according to the present invention be applied to simultaneously co-channel full duplex without
Line communication system places radio frequency system of the present invention in full-duplex wireless communication systems receiving antenna rear class.System
The useful reception signal that is received by the transmitting signal that replicates and receiving antenna of input signal and from the self-interference of transmitting antenna
The equal two parts composition of the sum of signal.
As shown in Fig. 2, in the present embodiment, the 1 input signal x of top set's directly modulated lasers prevention at radio-frequency port1(t) meter
It is as follows to calculate formula:
x1(t)=s (t)+n1(t)；
In formula: s (t) indicates the useful signal received, n1(t) self-interference signal received is indicated；
The 2 input signal x of inferior division directly modulated lasers prevention at radio-frequency port2(t) calculation formula is as follows:
x2(t)=n2(t)；
In formula: n2(t) the transmitting signal of duplication is indicated.
It is dry to match top set that the adjustable optical delay line and attenuator are used to adjust the amplitude and phase of inferior division signal
The amplitude and phase for disturbing signal are denoted as α x by the signal that adjustable optical delay line and attenuator convert by the signal of inferior division2
(t-τ)；
Two paths of signals output signal after the balance receiver is denoted as: y (t)；And
Y (t)=x1(t)-αx2(t- τ)=s (t)+n1(t)-αn2(t-τ)；
In formula: α indicates that attenuation coefficient, τ indicate delay volume, n2(t- τ) indicates n2(t) signal delayed when passing through；
By accurately adjusting adjustable optical delay line and attenuator, interference signal can be eliminated by being modulated to best match position
n1(t), faint useful signal s (t) is obtained.
As shown in figure 3, in the present embodiment, with Network Analyzer testing photoelectronic detector output signal and inputting certainly dry
Disturb signal ratio, be inhibited than with frequency curve；It can get and be greater than 40dB in 400MHz bandwidth at 900MHz centre frequency
Inhibition ratio.
As shown in figure 4, in the present embodiment, with Network Analyzer testing photoelectronic detector output signal and inputting certainly dry
Disturb signal ratio, be inhibited than with frequency curve；It can get and be greater than 33dB in 400MHz bandwidth at 2.4GHz centre frequency
Inhibition ratio.
As shown in figure 5, in the present embodiment, with Network Analyzer testing photoelectronic detector output signal and inputting certainly dry
Disturb signal ratio, be inhibited than with frequency curve；It can get the inhibition ratio for being greater than 27dB in 6GHz bandwidth.
Specific embodiments of the present invention are described above.It is to be appreciated that the invention is not limited to above-mentioned
Particular implementation, those skilled in the art can make various deformations or amendments within the scope of the claims, this not shadow
Ring substantive content of the invention.
Claims (5)
1. a kind of radio frequency system applied to co-channel full duplex system simultaneously characterized by comprising straight modulation
Laser, adjustable optical delay line, adjustable optical attenuator, balanced reciver；The upper branch of the straight modulation laser is connected to flat
The lower branch of the first input end of weighing apparatus receiver, the straight modulation laser passes sequentially through adjustable optical attenuator, tunable optical delay
Line is connected to the second input terminal of balanced reciver；Wherein,
The straight modulation laser includes the first RF signal input end mouth, the second RF signal input end mouth, and described first penetrates
Frequency signal input port be used to receive by and meanwhile co-channel full duplex system the useful signal that receives of receiving antenna and self-interference
Signal；The second RF signal input end mouth receives the transmitting letter of co-channel full duplex system transmitting antenna while duplication obtains
Number；
The adjustable optical delay line passes through time delay caused by different paths for matching self-interference signal；
The adjustable optical attenuator is used to match the amplitude size of self-interference signal；
The balanced reciver carries out subtraction fortune for receiving branch, lower branch two ways of optical signals on straight modulation laser
It calculates, is converted into corresponding electric signal output after obtaining useful optical signal；
Wherein, the system obtains the inhibition ratio for being greater than 33dB, in 900MHz in 400MHz bandwidth at 2.4GHz centre frequency
It is greater than the inhibition ratio of 40dB at centre frequency.
2. the radio frequency system according to claim 1 for being applied to co-channel full duplex system simultaneously, feature
It is, further includes single mode optical fiber, the upper branch of the straight modulation laser is connected to the of balanced reciver by single mode optical fiber
One input terminal.
3. the radio frequency system according to claim 1 for being applied to co-channel full duplex system simultaneously, feature
It is, radio frequency system configures the rear class of the receiving antenna, transmitting antenna of co-channel full duplex system at the same time.
4. the radio frequency system according to claim 1 for being applied to co-channel full duplex system simultaneously, feature
It is, the transmitting signal of co-channel full duplex system transmitting antenna refers to while duplication obtains: from co-channel full duplex system simultaneously
The transmitting signal that replicates of transmitting antenna front end.
5. the radio frequency system according to claim 1 for being applied to co-channel full duplex system simultaneously, feature
It is, further includes optical receiving device, it is certainly dry demodulates elimination for the electric signal of the optical receiving device receiving balance receiver output
Useful radiofrequency signal after disturbing.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106357299A (en) * | 2016-08-30 | 2017-01-25 | 上海交通大学 | Radio frequency self-interference eliminating system applied to in-band full duplex system integrating MIMO (multi-input multi-output) |
| CN106788579B (en) * | 2016-12-19 | 2020-01-07 | 上海交通大学 | In-band full-duplex wireless communication system and broadband optical self-interference elimination system thereof |
| CN108594479A (en) * | 2018-03-30 | 2018-09-28 | 张晗 | It is a kind of based on the full optical phase modulator of black phosphorus material and its application |
| CN110401491A (en) * | 2019-06-14 | 2019-11-01 | 中国电子科技集团公司第三十四研究所 | A kind of same location disturbance restraining method based on light processing |
| CN110703243A (en) * | 2019-09-29 | 2020-01-17 | 天津大学 | Novel silicon-based terahertz active array imaging technology based on regenerative reception principle |
| CN112468239B (en) * | 2020-10-29 | 2022-05-24 | 西安空间无线电技术研究所 | Multi-dimensional photoelectric combined simultaneous same-frequency full-duplex self-interference suppression system and method |
| CN112600587B (en) * | 2021-01-06 | 2021-09-28 | 上海交通大学 | Real-time adaptive optical self-interference elimination system and method based on FPGA and STM32 |
| CN113162693B (en) * | 2021-01-08 | 2022-10-11 | 北京工业大学 | Full-duplex communication system and method for eliminating radio frequency self-interference |
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| US7548567B2 (en) * | 2004-04-02 | 2009-06-16 | Vladimir Kupershmidt | Analog transmitter using an external cavity laser (ECL) |
| CN103209026B (en) * | 2013-02-28 | 2016-05-18 | 西南交通大学 | A kind of full duplex multi-service fusion light-carried wireless transmission system |
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