CN104253647B - Outdoor visible light communication system based on MIMO technology and OFDM technology - Google Patents
Outdoor visible light communication system based on MIMO technology and OFDM technology Download PDFInfo
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Abstract
The invention discloses a kind of outdoor visible light communication system based on MIMO technology and OFDM technology, it includes：Coding module, converts information into baseband digital signal, information is passed through electric signal transmission；Modulation module, baseband digital signal is modulated on carrier wave；Serioparallel exchange module；The signal of serial transmission is converted to the signal of multidiameter delay transmission；LED light group, including multiple LEDs, each LED by by multidiameter delay transmit in signal wherein signal is modulated all the way, Shi Ge roads signal is mutually orthogonal, then this way signal is converted into optical signal transmission gone out by electro-optic conversion；And, message recipient, including receive photoelectric conversion module, the subcarrier demodulation module being connected with photoelectric conversion module, the parallel serial conversion module being connected with subcarrier demodulation module, the demodulation module being connected with parallel serial conversion module and the decoder module connected with demodulation module of optical signal；For receiving optical signal, and it is converted into information.
Description
Technical field
The present invention relates to visible light communication system field, more particularly to it is a kind of based on MIMO technology and OFDM technology
Outdoor visible light communication system.
Background technology
Information after coding and modulation by forming electric signal, it is seen that optic communication is to apply light emitting diode, and electric signal is turned
Light signal is changed to, light transmission information is utilized；Photelectric receiver converts optical signals to electric signal, by being carried out to electric signal
Demodulation and decoding, extracts information.The characteristics of optic communication has strong antijamming capability, is not take up radio channel, realizes simple, room
The outer public illumination resource abundant with street lamp, advertising lamp, neon light, traffic lights etc., is carried out visible using these illumination resources
Optic communication, the problem of advantageously accounting for city wireless communication resource growing tension, expand wireless communication capacity, promote car networking and
The realization of Internet of Things.
At present, outdoor light is propagated in an atmosphere, and light signal strength is declined due to air to the scattering and absorption of light；Together
When, because the refraction and reflection of light, and light come from different light sources, the phase and time delay when light reaches receiver differ
Cause, add the influence of bias light, cause the generation of multipath fading, constrain the quality of outdoor visible light communication.
Therefore, prior art has yet to be improved and developed.
The content of the invention
It is an object of the invention to provide a kind of outdoor visible light communication system based on MIMO technology and OFDM technology, purport
Light signal strength is reduced to scattering, the absorption of light in solution air, and light comes from different light sources, light reaches receiver
When phase and time delay it is inconsistent, add the influence of bias light, cause the generation of multipath fading, constrain outdoor visible light communication
The technical problem of quality.
Technical scheme is as follows：A kind of outdoor visible light communication system based on MIMO technology and OFDM technology,
It includes：Coding module, converts information into baseband digital signal, information is passed through electric signal transmission；
Modulation module, baseband digital signal is modulated on carrier wave；
Serioparallel exchange module, the signal of serial transmission is converted to the signal of multidiameter delay transmission；
LED light group, including multiple LEDs, each LED transmit multidiameter delay the wherein subsignal all the way in signal
It is modulated, makes each way signal mutually orthogonal, then this way signal is converted into optical signal transmission by electro-optic conversion and goes out；
And,
Message recipient, including the subcarrier solution for receiving the photoelectric conversion module of optical signal, being connected with photoelectric conversion module
Mode transfer block, the parallel serial conversion module being connected with subcarrier demodulation module, the demodulation module being connected with parallel serial conversion module and with solution
The decoder module that mode transfer block connects；For receiving optical signal, and it is converted into information.
The described outdoor visible light communication system based on MIMO technology and OFDM technology, wherein, described LED includes
Subcarrier-modulated module and the photoelectric conversion module being connected with subcarrier-modulated module.
The described outdoor visible light communication system based on MIMO technology and OFDM technology, wherein, the LED also includes
Digital Up Convert module, described Digital Up Convert module is connected between subcarrier-modulated module and electrooptic conversion module, can
So that the frequency spectrum of signal is moved on in higher frequency.
The described outdoor visible light communication system based on MIMO technology and OFDM technology, wherein, the LED also includes
Protection interval inserts module, and it is connected between subcarrier-modulated module and digital up-converter module, for passing through subcarrier
Interval is added before and after the Signal coding of modulation.
The described outdoor visible light communication system based on MIMO technology and OFDM technology, wherein, the subcarrier-modulated
The technology that module is used is OFDM technology, and it is used to the multichannel subsignal of parallel transmission being modulated to mutually orthogonal subsignal.
The described outdoor visible light communication system based on MIMO technology and OFDM technology, wherein, the modulation module
Modulation system is analog signal modulation system, digital signal modulation mode or pulse signal modulation mode.
The described outdoor visible light communication system based on MIMO technology and OFDM technology, wherein, described information is received
Device also includes Digital Down Converter Module, and it is connected between photoelectric conversion module and subcarrier demodulation module.
The described outdoor visible light communication system based on MIMO technology and OFDM technology, wherein, described information is received
Device also includes removing protection interval module, wherein, described removal protection interval module is connected to Digital Down Converter Module and son
Between carrier wave demodulation module.
The described outdoor visible light communication system based on MIMO technology and OFDM technology, wherein, the LED light group and institute
Transmitting/the reception for stating message recipient uses MIMO technology.
The described outdoor visible light communication system based on MIMO technology and OFDM technology, wherein, the LED light group and institute
State message recipient and pass through wireless connection.
Beneficial effects of the present invention：Technical scheme can improve the diversity gain of information transfer, reduce signal strong
The decay of degree in an atmosphere, while reducing multipath fading and intersymbol interference, is conducive to the further stability of raising communication and logical
Believe speed；Additionally have the following advantages that：
1. carrying out information transfer using optical signal, radio resource, no electromagnetic interference are not take up；
2. transmitting same signal using multiple LEDs, the transimission power of signal can be effectively improved, is reduced due to light intensity
Decay is impacted to optical signal in outdoor transmissions；
3. using OFDM technology, signal decomposition is subjected to parallel transmission for mutually orthogonal subsignal, letter can be effectively improved
Number transmission speed；
, can be with while unlike signal is not interfere with each other after carrying out orthogonal modulation 4. high speed signal is decomposed into multi-path low speed signal
Effectively antagonize the multi-path jamming that the refraction due to light, reflection and scattering are produced；
5. protection interval is added in transmitting signal can further prevent intersymbol interference.
Brief description of the drawings
Fig. 1 is the structural representation of the present invention.
Fig. 2 is another structural representation of the present invention.
Embodiment
To make the objects, technical solutions and advantages of the present invention clearer, clear and definite, develop simultaneously embodiment pair referring to the drawings
The present invention is further described.
As shown in figure 1, the present invention provides a kind of outdoor visible light communication system based on MIMO technology and OFDM technology, its
Including：Coding module, converts information into baseband digital signal, information is passed through electric signal transmission；Modulation module, by base
With on digital signal modulated to carrier wave；Serioparallel exchange module, the signal of serial transmission is converted to the signal of multidiameter delay transmission；
LED light group, including multiple LEDs, each LED by multidiameter delay transmit signal wherein signal is modulated all the way, make
Each road signal is mutually orthogonal, then this road electric signal is converted into optical signal transmission and gone out by process electro-optic conversion；And, information is received
Device, including the subcarrier demodulation module and subcarrier solution for receiving the photoelectric conversion module of optical signal, being connected with photoelectric conversion module
Parallel serial conversion module, the demodulation module being connected with parallel serial conversion module and the decoding mould connected with demodulation module of mode transfer block connection
Block；For receiving optical signal, and it is converted into information.
After adopting the above technical scheme, the information sent is converted into baseband digital signal by coding module, in order to can
By the transmission of electric signal, then baseband digital signal is modulated in carrier wave in the presence of modulation module, so just may be used
To improve the antijamming capability of signal transmission；The signal of serial transmission is converted into parallel transmission by described serioparallel exchange module
Signal, is transmitted by different LEDs respectively, is transmitted same signal using multiple LEDs, can be effectively improved signal
Transimission power, is reduced because light intensity attenuation is impacted to optical signal in outdoor transmissions.In addition, the message recipient in the present invention
Electric signal is converted optical signals to by light-sensitive element, carried out the different subsignal in each road respectively using subcarrier demodulation module
Demodulation, described parallel serial conversion module reconfigures each way signal for serial signal all the way；Final serial signal is by solution
Reconcile and decode, revert to original signal.
The information of the present invention is converted into electric signal before this during transmission, then converts the electrical signal to optical signal,
By transmission of visible light information, without taking radio resource, without electromagnetic interference so that more efficient, the letter of information transfer
Cease integrity degree high, the effect of information transfer is more preferable.
As shown in Fig. 2 the invention discloses a kind of outdoor visible light communication system based on MIMO technology and OFDM technology,
It includes：Coding module, converts information into baseband digital signal, information is passed through electric signal transmission；Modulation module, will
Baseband digital signal is modulated at carrier wave；Serioparallel exchange module, the signal of serial transmission is converted to the signal of multidiameter delay transmission；
Wherein signal is modulated all the way in LED light group, including multiple LEDs, the signal that each LED transmits multidiameter delay,
Shi Ge roads signal is mutually orthogonal, then this road electric signal is converted into optical signal transmission and gone out by process electro-optic conversion；And, information connects
Device is received, including receives the photoelectric conversion module of optical signal, the subcarrier demodulation module being connected with photoelectric conversion module and subcarrier
Parallel serial conversion module, the demodulation module being connected with parallel serial conversion module and the decoding connected with demodulation module of demodulation module connection
Module；For receiving optical signal, and it is converted into information.
The present invention converts the information into electric signal during transmission, then will be serial in the effect of serioparallel exchange module
Signal be converted into parallel signal by the modulation of multiple LEDs, insertion interval, frequency modulation, be finally converted into optical signal transmission,
These conversions can effectively improve the efficiency of transmission of information, improve the transimission power of signal, reduce light intensity attenuation to optical signal
The influence caused in outdoor, can prevent intersymbol interference, the multi-path jamming that outdoor anaclasis, reflection and scattering are produced；Information connects
Receive device to receive after optical signal, electric signal is converted optical signals into the presence of photoelectric conversion module, is eventually passed a series of
Step：Down coversion, space code, subcarrier demodulation, demodulation, decoding are gone, be finally reduced into initial information.These modules and step
All it is indispensable part among band, it is ensured that the efficiency of information transfer, the Stability and veracity of information.
As shown in Fig. 2 each LED includes subcarrier-modulated module, protection interval insertion module, Digital Up Convert
Module and photoelectric conversion module, are sequentially connected respectively；Wherein, above-mentioned subcarrier-modulated module is used to modulate signals into mutual
In orthogonal carrier wave, the signal modulation after decomposition is set to be transmitted in each mutually orthogonal subchannel, each subsignal
Propagate simultaneously without interfering, protection interval insertion module adds interval in the Signal coding Jing Guo subcarrier-modulated,
Intersymbol interference can be prevented；Add behind interval, signal moves on to the frequency spectrum of signal by Digital Up Convert module higher frequency
On, signal antijamming capability is improved, increases signal transmission distance；Converted signals are by electro-optic conversion, by LED lamplight by information
Transmitted by visible ray.
The technology that above-mentioned subcarrier-modulated module is used is OFDM technology, and it is mutually orthogonal son that it, which is used for signal decomposition,
Signal.
The subcarrier-modulated module of the present invention is modulated signals into mutually orthogonal carrier wave using OFDM technology, makes decomposition
Signal modulation afterwards is transmitted in each mutually orthogonal subchannel, and each subsignal parallel transmission is without mutually dry
Disturb；It is also that high speed signal is decomposed into multi-path low speed signal simultaneously, unlike signal is not interfere with each other after carrying out orthogonal modulation, Ke Yiyou
Effect confrontation is produced the multi-path jamming of refraction, reflection and scattering by light.
The modulation system of above-mentioned modulation module is that analog signal modulation system, digital signal modulation mode or pulse signal are adjusted
Mode processed.
After adopting the above technical scheme, baseband digital signal is modulated at load by information by the present invention by these modulation systems
In ripple, the antijamming capability of signal transmission can be effectively improved.
Above-mentioned message recipient also includes Digital Down Converter Module, and it is connected to photoelectric conversion module and subcarrier demodulation
Between module；During use, Digital Down Converter Module will pass through the letter of Digital Up Convert module raises frequency in LED
Number low frequency is adjusted to, is converted to baseband signal.
Above-mentioned message recipient also includes removing protection interval module, wherein, described removal protection interval module connects
It is connected between Digital Down Converter Module and subcarrier demodulation module.
After above-mentioned technical scheme, the removal protection interval module in the present invention is removed before transmission between the protection of insertion
Reduced every to signal so that the information completely that message recipient is received, change will not be produced, it is ensured that information it is accurate
Property.
In actual use, above-mentioned LED light group and transmitting/reception of described information receiver use MIMO technology；Adopt
Received with multiple wireless transmitting and multiple wireless, transmitting is mutually corresponding with receiving so that the speed of information transfer is more quick, subtracts
Few information decays during transmission.
In actual use, above-mentioned LED light group and described information receiver are by wireless connection, during transmission
The optical signal after turning is transmitted using visible ray, with strong antijamming capability, radio channel, the simple spy of realization is not take up
Point, and it is outdoor there is abundant public illumination resource, these illumination resources carry out visible light communications, advantageously account for city without
The problem of line communication resource growing tension, expand wireless communication capacity, promote the realization of car networking and Internet of Things.
Information decomposition is multiple subsignals by technical scheme, and each subsignal is passed by different light
It is defeated；It is modulated at using each subsignal in overlapped and mutually orthogonal sub-band；Receiver sub-signal carries out subcarrier
Demodulation is synthesized, you can recover prime information, can also be inserted space coding to information as needed, further be improved anti-multipath fading
Ability.
It should be appreciated that the application of the present invention is not limited to above-mentioned citing, for those of ordinary skills, can
To be improved or converted according to the above description, all these modifications and variations should all belong to the guarantor of appended claims of the present invention
Protect scope.
Claims (7)
1. a kind of outdoor visible light communication system based on MIMO technology and OFDM technology, it is characterised in that including：Encode mould
Block, converts information into baseband digital signal, information is passed through electric signal transmission；
Modulation module, baseband digital signal is modulated on carrier wave；
Serioparallel exchange module, the signal of serial transmission is converted to the signal of multidiameter delay transmission；
The signal of the serial transmission is the modulated signal that modulation module is exported；
LED light group, including multiple LEDs, each LED by multidiameter delay transmit signal in wherein signal is adjusted all the way
Make, Shi Ge roads signal is mutually orthogonal, then this road electric signal is converted into optical signal transmission by electro-optic conversion and go out；And,
Message recipient, including the subcarrier demodulation mould for receiving the photoelectric conversion module of optical signal, being connected with photoelectric conversion module
Block, the parallel serial conversion module being connected with subcarrier demodulation module, the demodulation module being connected with parallel serial conversion module and with solution mode transfer
The decoder module that block connects；For receiving optical signal, and it is converted into information；
Described LED includes subcarrier-modulated module and the electrooptic conversion module being connected with subcarrier-modulated module；
The LED also includes protection interval and inserts module, and it is connected with subcarrier-modulated module, for being adjusted by subcarrier
Interval is added before and after the Signal coding of system；
The technology that the subcarrier-modulated module is used is OFDM technology, and it is mutually orthogonal son letter that it, which is used for signal decomposition,
Number；
The subcarrier-modulated module is used to modulate signals into mutually orthogonal carrier wave, makes the signal modulation after decomposition to often
It is transmitted in individual mutually orthogonal subchannel, each subsignal is propagated without interfering simultaneously；The subcarrier-modulated
Module is additionally operable to high speed signal being decomposed into multi-path low speed signal.
2. the outdoor visible light communication system according to claim 1 based on MIMO technology and OFDM technology, its feature exists
In, the LED also includes Digital Up Convert module, and described Digital Up Convert module connects with protection interval insertion module,
The frequency spectrum of signal is moved on in higher frequency.
3. the outdoor visible light communication system according to claim 1 based on MIMO technology and OFDM technology, its feature exists
In the modulation system of the modulation module is analog signal modulation system, digital signal modulation mode or pulse signal modulation side
Formula.
4. the outdoor visible light communication system according to claim 1 based on MIMO technology and OFDM technology, its feature exists
In described message recipient also includes Digital Down Converter Module, and it is connected to photoelectric conversion module and subcarrier demodulation module
Between.
5. the outdoor visible light communication system according to claim 4 based on MIMO technology and OFDM technology, its feature exists
In, described message recipient also includes removing protection interval module, wherein, described removal protection interval module is connected to number
Between word down conversion module and subcarrier demodulation module.
6. the outdoor visible light communication system according to claim 1 based on MIMO technology and OFDM technology, its feature exists
In the LED light group and transmitting/reception of described information receiver use MIMO technology.
7. the outdoor visible light communication system according to claim 6 based on MIMO technology and OFDM technology, its feature exists
In the LED light group passes through wireless connection with described information receiver.
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| CN104966415A (en) * | 2015-06-15 | 2015-10-07 | 上海交通大学 | Vehicle safety control method and system based on LED visible light communication technology |
| CN105515658A (en) * | 2015-11-24 | 2016-04-20 | 广东顺德中山大学卡内基梅隆大学国际联合研究院 | Precoded MIMO-OOFDM visible light communication method |
| CN106130632B (en) * | 2016-06-28 | 2018-10-16 | 维沃移动通信有限公司 | Data transmission method and electronic equipment |
| CN107482031B (en) * | 2017-08-09 | 2020-05-05 | 南京邮电大学 | GaN-based micron-scale LED array and preparation method thereof |
| CN207543109U (en) * | 2017-11-28 | 2018-06-26 | 广州市浩洋电子股份有限公司 | A kind of visible light communication system based on SDR technologies |
| CN109639362B (en) * | 2018-11-27 | 2022-04-12 | 南京邮电大学 | Multi-input multi-output optical communication system and communication method based on scattering effect |
| CN112272050B (en) * | 2020-09-21 | 2021-08-10 | 南京驭逡通信科技有限公司 | MIMO optical wireless communication system based on image acquisition and communication processing method thereof |
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