CN106850077A - A kind of wireless coherent CDMA optical communication system and communication means - Google Patents
A kind of wireless coherent CDMA optical communication system and communication means Download PDFInfo
- Publication number
- CN106850077A CN106850077A CN201710017594.0A CN201710017594A CN106850077A CN 106850077 A CN106850077 A CN 106850077A CN 201710017594 A CN201710017594 A CN 201710017594A CN 106850077 A CN106850077 A CN 106850077A
- Authority
- CN
- China
- Prior art keywords
- signal
- phase
- way
- light
- modulator
- 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
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
- H04B10/60—Receivers
- H04B10/61—Coherent receivers
-
- 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
- H04B10/60—Receivers
- H04B10/61—Coherent receivers
- H04B10/615—Arrangements affecting the optical part of the receiver
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optical Communication System (AREA)
Abstract
The invention discloses a kind of wireless light communication coherent CDMA system and communication means, including laser, signal source, transmitter module and receiver module；The light that laser is produced is divided into two-way light wave, merges into light all the way by coupler after ovennodulation and launches；Reception antenna is by space optical coupling to optical fiber, it is divided into two-beam ripple, is modulated respectively through the modulated signal of the orthogonal code corresponding to transmitter terminal, then by coupler, and photoelectric current output treatment is converted to through balanced detector, it is derived from the information sequence that transmitting terminal is launched.The present invention suppresses the phase fluctuation that atmospheric channel causes using the access way of coherent CDMA, is more suitable for wireless light communication multi-user access system, improve system channel utilization rate, the interference between user is reduced, with preferable performance and relatively low system complexity, the practical of system is more beneficial for.
Description
Technical field
The present invention relates to wireless OCDMA communication technical field, more particularly to a kind of wireless light communication for atmospheric channel
Wireless coherent CDMA (Code Division Multiple Access, the CDMA) optical communication system of multiple access and
Communication means.
Background technology
Radio optical communication system obtains researcher and more and more pays close attention to as a kind of new communication mode.Compared to existing
Some wireless communication technologys, wireless light communication has small high bandwidth, size, electromagnetism interference, is easy to set up and secrecy high
The advantages of property.And CDMA allows the advantages of synchronous user or asynchronous access due to it, also it is subject to more next in optical communication system
The concern of more scholars.So far, optical cdma system is mainly using relevant or non-coherent modulation two schemes.Incoherent tune
That system considers is light orthogonal code (OCCs), but to obtain the orthogonality of relatively good intersymbol, it is necessary to use sufficiently long code.Have
Researcher proposes to realize the use of bipolar code in non-coherent modulation, so that improve a yard orthogonality, but, compared to incoherent
For modulation, coherent light communication has more preferable channel utilization and with sensitivity higher.Therefore, wireless coherent light leads to
Letter receives everybody extensive concern as a kind of new communication mode.Existing researcher devises and needs to use local lasing light emitter
Carry out the Coherent Optical CDMA of signal demodulation.But, because the performance of radio optical communication system is influenceed by atmospheric turbulance,
The phase fluctuation that especially atmospheric turbulance causes, has very big limitation to coherent system, therefore, wireless light communication coherent light
CDMA access system problems faceds, one is accurate carrier phase synchronization, and two is the phase fluctuation that turbulent flow causes.
At present, the more existing solution for phase fluctuation can be divided into using Phase Compensation Algorithm and lock phase using light
Ring method.Wherein, most Phase Compensation Algorithm is more complicated, and processed offline is suitable to mostly, it is difficult in Real-Time Optical communication system
Used in system.The fluctuating of phase can be also tracked using Optical phase-locked loop, is beneficial to the performance for improving coherent system.But, light lock
Phase ring not only complex structure, and due to factors such as response time, transmission delays, limit its making in actual optical communication system
With.Therefore, existing communication system and communication means are difficult to suppress the phase fluctuation that atmospheric channel causes, many for wireless light communication
The applicability of subscriber access system is not high.
The content of the invention
In order to overcome the above-mentioned deficiencies of the prior art, for radio optical communication system transmission channel the characteristics of, the present invention is carried
For a kind of new wireless light communication coherent CDMA system and communication means, with the access way of coherent CDMA, suppress atmospheric channel
The phase fluctuation for causing, is more suitable for wireless light communication multi-user access system, to solve multiple access in wireless light communication
Problem.Compared to existing traditional multiple access mode, the present invention has preferable performance and relatively low system complexity,
The practical of system is more beneficial for, system channel utilization rate can either be improved, the use of bipolar code can be realized again, so as to drop
Interference between low user.
Principle of the invention is：For each user, the present invention will come from the same two-way light wave of laser and use
Mutually orthogonal orthogonal code is modulated, wherein loading user profile all the way.In receiver end, by with mutually orthogonal orthogonal code
The information of modulation is interfered, is adjudicated, so as to extract information sequence.The shadow of similar atmospheric channel is subject to due to two-beam
Ring, therefore in interventional procedures, the phase fluctuation reduction that largely can cause atmospheric turbulance, so as to obtain preferably
Performance.
The present invention provide technical scheme be：
A kind of wireless coherent CDMA optical communication system, including laser, signal source, transmitter module and receiver module；
Wherein：
Transmitter module includes phase-modulator, 1 × 2 beam splitter, 2 × 1 couplers and transmitting antenna；Wherein 1 × 2 beam splitting
It is attached by optical fiber between device, phase-modulator and laser；Pass through to transmitting antenna from phase-modulator output
Optical fiber is attached；Connected by microwave line between signal source and phase-modulator；
Receiver module includes reception antenna, 1 × 2 beam splitter, phase-modulator, 2 × 2 couplers, balanced detector, letter
Number processing module and control link；Wherein reception antenna, 1 × 2 beam splitter, phase-modulator, 2 × 2 couplers, balanced detector
Between connected with optical fiber；Connected with microwave line after balanced detector detection and exported；Control link carries out signal biography using microwave line
It is defeated；
Operationally, the light of laser output is divided into two-beam ripple to transmitter module by 1 × 2 beam splitter, sets again
The transmission signal of signal source is counted, transmission signal is modulated on two-beam ripple respectively by phase-modulator；Two beams after modulation
Light wave is coupled as a branch of light wave by 2 × 1 couplers, is sent into atmospheric channel light wave by transmitting antenna, as space
Light；
Wherein, the two-beam ripple being divided into by 1 × 2 beam splitter, due to being obtained from a branch of light wave, therefore, with identical
Angular frequency and initial phase；Two-way lightwave signal is distinguished using mutually orthogonal orthogonal code, that is, the two-way transmission letter for designing
Cease to modulate two ways of optical signals respectively；
Redesign the transmission signal of signal source, including two-way transmission signal；Wherein signal is produced by signal source all the way
Information spreads by orthogonal code 1 and constitutes, corresponding to the i user's transmitted information after Direct-Spread；Another road signal by with just
The orthogonal code 2 for handing over code 1 orthogonal is constituted, and correspondence is using the information sequence orthogonal with i user's spread spectrum code-phase；
Operationally, reception antenna is by space optical coupling to optical fiber for receiver module；The light being coupled into optical fiber passes through 1
× 2 beam splitters are divided into two-beam, and by the different signal of phase modulator modulation, institute's modulated signal is corresponding to transmitter terminal just
Hand over code；Orthogonal code is controlled according to signal processing module by controlling link, in order to reduce the interference between user；Through difference
The light wave of phase modulator modulation, then photoelectric current is converted to by 2 × 2 couplers and balanced detector, processed in electrical domain.
Wherein, transmitting to the spatial light in space is influenceed by atmospheric turbulance, is received using optical antenna in receiving terminal,
Transmitted coupled in optical fiber；In receiver module, it is not necessary to another laser as local oscillator light, by by transmitting terminal by just
Friendship code is distinguished, two-beam is coupled, you can to obtain the demodulation of information.The two-way light wave obtained by beam splitter passes through phase
The different information (signal) of position modulators modulate, wherein the modulation intelligence of light wave corresponds to the first via signal of emitter all the way
Orthogonal code, the modulation intelligence of another road light wave corresponds to the orthogonal code of the second road signal of emitter；Further, pass through
The electric signal of balanced detector detection completes demodulation by after sampling, correlation being done in electrical domain, obtains emitter transmitting (transmission)
Information.Signal processing module carries out signal transacting by the signal transacting Mathematical Modeling of formula 1：
Wherein, y [k] is the information sequence (information sequence that i.e. receiving terminal demodulation is obtained) of receiving terminal final output；K is represented
The sequence number that signal value occurs in the sequence；I [l] represents the electric signal that sampling is obtained；Using the code of orthogonal code in N expression systems
It is long.
Above-mentioned treatment is carried out by computer, the information sequence that transmitting terminal is launched is obtained.
Compared with prior art, the beneficial effects of the invention are as follows：
The present invention provides a kind of new wireless light communication coherent CDMA system and communication means, with the access side of coherent CDMA
Formula, suppresses the phase fluctuation that atmospheric channel causes.It is concerned with caused by the reasons such as the phase fluctuation caused for atmospheric turbulance wireless
The complexity of optical communication system Phase Tracking in demodulation, technical solution of the present invention is easy and effective, can locally swash not using
The demodulation of phase-modulated signal is completed under conditions of light device；Two-way light experience identical channel is additionally, since, therefore, the present invention can have
Effect suppresses phase noise.The system that the present invention is provided is especially suitable for radio optical communication system multiple access mode.
Compared with existing access way, the present invention uses CDMA access ways, it is allowed to the asynchronous access between user；
In receiver module, it is not necessary to which another laser is used as local oscillator light.Meanwhile, for wireless light communication CDMA access ways, lead to
Cross and use coherent communication technology, realize the use of bipolar code, and existing traditional unipolarity light orthogonal code (optical
Orthogonal code, OOC) code-phase ratio, can further reduce the interference between user.
Brief description of the drawings
Fig. 1 is the structured flowchart of wireless coherent CDMA optical communication system provided in an embodiment of the present invention；
Wherein, system includes transmitter module and receiver module；In figure solid arrow represent torrent of light to；Dotted line arrow
Head represents electric signal (including control signal) flow direction；01 is signal source；02 is laser；03 is orthogonal code；04 is with 03 phase just
The code of friendship；05 is 1 × 2 beam splitter；06 is phase-modulator；07 is 2 × 1 couplers；08 is 2 × 2 couplers；09 visits for balance
Survey device；10 is control link module；11 is signal processing module；12 is transmitting antenna；13 is reception antenna.
Fig. 2 is the FB(flow block) of communication means used in the embodiment of the present invention.
Specific embodiment
Below in conjunction with the accompanying drawings, the present invention, the model of but do not limit the invention in any way are further described by embodiment
Enclose.
The present invention provides a kind of wireless coherent CDMA optical communication system and communication means, with the access way of coherent CDMA,
Suppress the phase fluctuation that atmospheric channel causes, wireless light communication multi-user access system is more suitable for, to solve wireless light communication
The problem of middle multiple access.It is of the invention with preferable performance and relatively low compared to existing traditional multiple access mode
System complexity, be more beneficial for the practical of system, system channel utilization rate can either be improved, bipolar code can be realized again
Use so that the interference between reducing user.
As shown in Figure 1, system includes transmitter and receiver to the wireless coherent CDMA optical communication system that the present invention is provided
Two parts.Wherein, transmitter section includes phase-modulator, 1 × 2 beam splitter, 2 × 1 couplers and transmitting antenna.Receiver bag
Include reception antenna, 1 × 2 beam splitter, phase-modulator, 2 × 2 couplers and balanced detector.The function of transmitter section is
The information that will be transmitted loaded on and be transmitted on light wave.In accompanying drawing 1,02 represents laser, and the light that laser is produced is used as logical
The carrier wave of letter system, two parts are divided into by 1 × 2 beam splitter shown in 05 by the light that laser is produced；Correspondence modulates weight respectively
Newly-designed two-way information (signal), wherein the information that information signal source as shown in 01 is produced all the way is by the orthogonal code shown in 03
Spread spectrum is constituted, and orthogonal code of another road information shown in 04 is constituted.Mutually orthogonal code is represented due to 03 and 04, therefore, two-way
Light wave is maintained at quadrature by modulating different orthogonal codes.Two-way information is modulated to two-way light respectively by phase-modulator
On ripple, modulated using biphase phase shift keying (BPSK).Light all the way is merged into by 2 × 1 couplers through the two-way light of ovennodulation,
And atmospheric channel is launched in by transmitting antenna is transmitted.
Fig. 2 illustrates the workflow of the communication means of embodiment of the present invention use, as described above, transmitting antenna will be through coupling
The optical signal launch that clutch merges into all the way is transmitted in atmospheric channel；In receiver section, emitter is launched to space
In light received, demodulate and complete judgement, extraction obtain the information that emitter is launched.First, received by 13 Suo Shi
Antenna will be optically coupled to Optical Fiber Transmission in space channel；Two-way light wave is divided into by 1 × 2 beam splitter shown in 05；Use 06 institute
Show that phase-modulator is modulated respectively to two-way light wave, wherein the modulation intelligence of light wave is that orthogonal code corresponds to shown in 03 all the way
The first via signal of emitter, the modulation intelligence of another road light wave is the orthogonal code shown in 04, corresponding to the second tunnel of emitter
Signal；Two paths of signals is controlled by the control link shown in the signal processing module and 10 shown in 11, to reduce between user
Orthogonality between interference and guarantee two paths of signals.
The two-way light wave that will be modulated couples interference by 2 × 2 couplers shown in 08, and is converted through balanced detector detection
For photoelectric current is exported.The signal processing module that the photoelectricity of conversion flows through shown in 11 is sampled and is processed, final output result.Letter
Number processing module carries out signal transacting by the signal transacting Mathematical Modeling of formula 1：
Wherein, y [k] is the information sequence (information sequence that i.e. receiving terminal demodulation is obtained) of receiving terminal final output, and k is represented
The sequence number that signal value occurs in the sequence；I [l] represents the electric signal that sampling is obtained；Using the code of orthogonal code in N expression systems
It is long.
It is final to obtain the information sequence that transmitting terminal is launched by the treatment of computer.
It should be noted that the purpose for publicizing and implementing example is help further understands the present invention, but the skill of this area
Art personnel be appreciated that：Do not departing from the present invention and spirit and scope of the appended claims, various substitutions and modifications are all
It is possible.Therefore, the present invention should not be limited to embodiment disclosure of that, and the scope of protection of present invention is with claim
The scope that book is defined is defined.
Claims (6)
1. a kind of wireless coherent CDMA optical communication system, including laser, signal source, transmitter module and receiver module；
The transmitter module includes phase-modulator, 1 × 2 beam splitter, 2 × 1 couplers and transmitting antenna；Wherein 1 × 2 beam splitting
It is attached by optical fiber between device, phase-modulator and laser；Pass through optical fiber between phase-modulator to transmitting antenna
It is attached；Connected by microwave line between signal source and phase-modulator；
The receiver module includes reception antenna, 1 × 2 beam splitter, phase-modulator, 2 × 2 couplers, balanced detector, letter
Number processing module and control link；Wherein, the reception antenna, 1 × 2 beam splitter, phase-modulator, 2 × 2 couplers, balance
Connected with optical fiber between detector；After the balanced detector detection output to the signal processing module is connected with microwave line；
Control link carries out signal transmission using microwave line；
The light that the laser is produced is divided into as the carrier wave of communication system by 1 × 2 beam splitter of the transmitter module
Two parts, as two-way light wave；The transmission signal of the signal source is adjusted respectively by the phase-modulator of the transmitter module
It is formed on the two-way light wave, two-way light wave is maintained at quadrature by modulating different orthogonal codes；Through the two of ovennodulation
Road light wave merges into light all the way by 2 × 1 couplers of the transmitter module, and is launched in air letter by transmitting antenna
Road, is transmitted as spatial light；
The reception antenna is by space optical coupling to optical fiber；It is coupled into the light in optical fiber by the receiver module 1 × 2
Beam splitter is divided into two-beam ripple, and two-way light wave is modulated respectively using the phase-modulator of the receiver module, is adjusted
Signal processed corresponds respectively to the orthogonal code of transmitter terminal, and orthogonal code is controlled by the signal processing module and control link；Through
The two-way light wave of modulation couples interference by 2 × 2 couplers of the receiver module again, and detects conversion through balanced detector
It is that the signal processing module is arrived in photoelectric current output, is processed in electrical domain, is derived from the information sequence that transmitting terminal is launched.
2. a kind of wireless coherent CDMA optical communication method, by the access way using coherent CDMA, suppresses atmospheric channel and causes
Phase fluctuation, improve system channel utilization rate, the use of bipolar code is realized, so as to reduce wireless light communication multiple access
Inter-user interference；Comprise the following steps：
1) carrier wave of the light for producing laser as communication system；The beam splitter that the light that laser is produced passes through transmitter module
It is divided into two parts, as two-way light wave；
2) transmission signal is sent by signal source, the transmission signal is modulated to step respectively by the phase-modulator of transmitter module
On rapid 1) described two-way light wave, the two-way light wave is maintained at quadrature by modulating different orthogonal codes；
3) light all the way is merged into by the coupler of transmitter module through the two-way light wave of ovennodulation, and is launched by transmitting antenna
In atmospheric channel, it is transmitted as spatial light；
4) reception antenna is by space optical coupling to optical fiber；The light being coupled into optical fiber is divided into by the beam splitter of receiver module
Two-beam ripple；
5) two-way light wave is modulated respectively using the phase-modulator of receiver module, institute's modulated signal corresponds respectively to hair
The orthogonal code of generator terminal is penetrated, orthogonal code is controlled by the signal processing module and control link；
6) modulated two-way light wave couples interference by the coupler of the receiver module again, and is detected through balanced detector
Be converted to photoelectric current output to the signal processing module；
7) signal processing module is sampled to photoelectric current, by demodulation, is derived from the information sequence that transmitting terminal is launched
Row.
3. optical communication method as claimed in claim 2, it is characterized in that, step 2) transmission signal of the signal source includes that two-way is passed
Defeated signal；The information that wherein signal is produced by signal source all the way is constituted by the spread spectrum of orthogonal code 1, corresponding to the use after Direct-Spread
Family transmitted information；Another road signal is made up of the orthogonal code 2 orthogonal with orthogonal code 1, and correspondence is used and user's spreading code
Mutually orthogonal information sequence.
4. optical communication method as claimed in claim 2, it is characterized in that, step 2) it is modulated using biphase phase shift keying method.
5. optical communication method as claimed in claim 2, it is characterized in that, step 7) signal processing module signal that passes through formula 1
Treatment Mathematical Modeling carries out signal transacting, obtains the information sequence that transmitting terminal is launched：
Wherein, y [k] is the information sequence of receiving terminal final output, i.e., the information sequence that receiving terminal demodulation is obtained；K represents signal
The sequence number that value occurs in the sequence；I [l] represents the electric signal that sampling is obtained；Using the code length of orthogonal code in N expression systems.
6. optical communication method as claimed in claim 2, it is characterized in that, step 1) beam splitter of the transmitter module is 1 × 2 point
Beam device；Step 3) transmitter module coupler be 2 × 1 couplers；Step 4) receiver module beam splitter be 1
× 2 beam splitters；Step 6) receiver module coupler be 2 × 2 couplers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710017594.0A CN106850077B (en) | 2017-01-11 | 2017-01-11 | A kind of wireless coherent CDMA optical communication system and communication means |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710017594.0A CN106850077B (en) | 2017-01-11 | 2017-01-11 | A kind of wireless coherent CDMA optical communication system and communication means |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106850077A true CN106850077A (en) | 2017-06-13 |
| CN106850077B CN106850077B (en) | 2019-01-29 |
Family
ID=59118617
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710017594.0A Expired - Fee Related CN106850077B (en) | 2017-01-11 | 2017-01-11 | A kind of wireless coherent CDMA optical communication system and communication means |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106850077B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050226615A1 (en) * | 2004-04-05 | 2005-10-13 | The Boeing Company | Phase-encoded optical code division multiple access |
| US20100183309A1 (en) * | 2005-02-18 | 2010-07-22 | Telcordia Technologies, Inc. | System and Method for OCDM-Based Photonic Layer Security Robustness to Archival Attack |
| CN102324974A (en) * | 2011-07-08 | 2012-01-18 | 北京邮电大学 | A kind of visible light communication system and device thereof based on the OCDMA technology |
| CN105871464A (en) * | 2016-05-19 | 2016-08-17 | 北京大学 | Wireless optical communication system and modulation-demodulation method |
-
2017
- 2017-01-11 CN CN201710017594.0A patent/CN106850077B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050226615A1 (en) * | 2004-04-05 | 2005-10-13 | The Boeing Company | Phase-encoded optical code division multiple access |
| US20100183309A1 (en) * | 2005-02-18 | 2010-07-22 | Telcordia Technologies, Inc. | System and Method for OCDM-Based Photonic Layer Security Robustness to Archival Attack |
| CN102324974A (en) * | 2011-07-08 | 2012-01-18 | 北京邮电大学 | A kind of visible light communication system and device thereof based on the OCDMA technology |
| CN105871464A (en) * | 2016-05-19 | 2016-08-17 | 北京大学 | Wireless optical communication system and modulation-demodulation method |
Non-Patent Citations (2)
| Title |
|---|
| MAHMOUD JAZAYERIFAR等: ""Atmospheric optical CDMA communication systems via optical orthogonal codes"", 《IEEE TRANSACTIONS ON COMMUNICATIONS》 * |
| REZA MIRZAEI NEJAD等: ""Two-Stage Code Acquisition in Wireless Optical CDMA Communications Using Optical Orthogonal Codes"", 《 IEEE TRANSACTIONS ON COMMUNICATIONS 》 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106850077B (en) | 2019-01-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Ali et al. | Design analysis and performance evaluation of the WDM integration with CO-OFDM system for radio over fiber system | |
| CN105871499B (en) | Ultra-high-speed spatial coherent optical communication method and system based on optical frequency comb | |
| CN109818680B (en) | Microwave photon broadband radio frequency transceiving method and device | |
| CN109586911A (en) | Continuous variable quantum key delivering method based on coherent optical communication system | |
| CN104283609A (en) | Direct detection method and system based on two-channel orthogonal pilot frequency optical signals and device | |
| CN106603158A (en) | High-precision distributed optical fiber frequency transfer method | |
| CN106603156B (en) | Terahertz digital communication system and method based on polarization coding | |
| CN106788704A (en) | The measuring system and method for the less fundamental mode optical fibre intermode time delay based on synchronizing sequence | |
| CN104410462A (en) | Polarization-multiplexing-based method and device for modulating and directly detecting optical signals | |
| CN110061783A (en) | A kind of optical-fiber wireless Transmission system for completing I/Q modulation based on both arms MZ Mach-Zehnder | |
| CN103595477A (en) | Method and device for carrying out up-conversion on data signals | |
| Joseph et al. | Performance analysis and optimization of radio over fiber link | |
| Hai et al. | Remote phase-shift LiDAR with communication | |
| Kim et al. | Demonstration of real-time coherent 10-Gb/s QPSK reception implemented on a commodity server | |
| Li et al. | A novel coherent OCDMA scheme over atmospheric turbulence channels | |
| JP2020109887A (en) | Optical transmission method and optical transmission device | |
| Cano et al. | 7.5 Gb/s direct DFB phase modulation with 8-DPSK for 6.25 GHz spaced coherent UDWDM-PONs | |
| Magidi et al. | Analysis of multi-pulse position modulation free space optical communication system employing wavelength and time diversity over Malaga turbulence channel | |
| CN106850077B (en) | A kind of wireless coherent CDMA optical communication system and communication means | |
| CN114189555B (en) | Signal format conversion method and device | |
| Kumar et al. | Effect of signal direct detection on sub-carrier multiplexed radio over fiber system | |
| KR0173911B1 (en) | Communication system using cdma modulating demodulating mathod reducing interference | |
| CN206341220U (en) | Terahertz digital communication system based on polarization coding | |
| CN115189715B (en) | Optical transmission device and method based on direct spread spectrum time division multiplexing | |
| CN105049126B (en) | A kind of light phase modulation method for transmitting signals based on multi-polarization state |
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 | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20190129 Termination date: 20220111 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |