CN110474684A - A kind of broad sense dimming controlling method based on more LED visible light communication systems - Google Patents
A kind of broad sense dimming controlling method based on more LED visible light communication systems Download PDFInfo
- Publication number
- CN110474684A CN110474684A CN201910824766.4A CN201910824766A CN110474684A CN 110474684 A CN110474684 A CN 110474684A CN 201910824766 A CN201910824766 A CN 201910824766A CN 110474684 A CN110474684 A CN 110474684A
- Authority
- CN
- China
- Prior art keywords
- matrix
- led
- empty
- vector
- follows
- 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
- H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
- H04B10/114—Indoor or close-range type systems
- H04B10/116—Visible light communication
-
- 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
- H04B10/502—LED 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
- H04B10/5161—Combination of different modulation schemes
-
- 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
- H04B10/524—Pulse 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
- H04B10/516—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
- H04B10/60—Receivers
Abstract
The invention discloses a kind of broad sense dimming controlling methods based on more LED visible light communication systems, belong to wireless communication field.Building mixing light-adjusting module, matrix activation element number when initialization is empty by source bit bit string and are transformed to multiple data blocks, each data block is mapped as matrix when a sky, and information is transmitted as unit of matrix when sky by visible light communication channel first；The DC current gain of subscriber channel matrix is calculated, the electric signal receiving matrix that optical detector is converted to is detected by maximum likelihood detector, demodulated；Joint circle of corresponding system bit error rate when activating different number elements when calculating empty in matrix, using the minimum bit error rate of system as optimization aim, using dimming level and spectrum efficiency as constraint condition, the optimal value of matrix activation element number when determining empty.The present invention has effectively taken into account communication and the illumination functions of visible light communication system, can effectively improve the energy efficiency of system, enhances the bit error rate performance of system.
Description
Technical field
The invention belongs to wireless communication technology fields, and in particular to a kind of broad sense based on more LED visible light communication systems
Dimming controlling method.
Background technique
In recent years, have many advantages, such as that the service life is long, moisture-proof is high, new generation of green lighting source light emitting diode low in energy consumption
(Light Emitting Diodes, LED) is gradually replacing traditional incandescent lamp and fluorescent lamp.LED lighting technology not only has
There is energy conservation, has also pushed the development of visible light communication (Visible Light Communications, VLC), VLC benefit
With LED issue visually observe less than High Speed Modulation light wave signal to modulates information and transmission.Phase is wirelessly communicated compared with conventional radio frequency
Have that frequency spectrum resource is abundant, without electromagnetic interference, highly-safe, broad covered area and can be realized simultaneously illumination and communication function than, VLC
The characteristics of energy[1], these advantages promote VLC to receive more and more attention.802.15 WLAN working group of IEEE is built
IEEE802.15.7VLC task groups have been found, and have speciallyyed permit the standard that the task groups write VLC physical layer and network layer[2]。
The communication function of VLC has been receive a lot of attention, but to meet the energy saving requirement and business in practical application
Feasibility, it is also necessary to consider its illumination functions, brightness adjustment control can effectively meet energy saving requirement.Therefore, communication and illumination are taken into account
The VLC system of function needs to have dimming function simultaneously.However, light modulation adversely affects communication, it is main that this is that VLC faces
One of challenge.High effective controlling light Integration ofTechnology will be significantly improved into energy-saving effect into VLC system, and user is allowed to fully control photograph
Bright output, making the practical application of VLC, more rationally therefore design tunable optical VLC system is of great significance.
The brightness adjustment control mode of existing VLC system can be roughly divided into simulation light modulation (Analogue Dimming, AD), number
Dim (Digital Dimming, DD), space light modulation (Spatial Dimming, SD) and mixing light modulation (Hybrid
Dimming, HD) four classes.Wherein, simulation dims the direct current biasing by adjusting transmitting signal to control dimming level, this method
It is the method most easily realized, but changes direct current biasing and will affect launch wavelength, the problem of so as to cause chroma offset[3]；In addition,
Since too high or too low direct current biasing can generate peak clipping noise, communication performance is limited obvious by dimming level.Number is adjusted
Light adjusts dimming level by adjusting the duty ratio for sending signal[4], this method solve dimming scope in simulation light modulation is limited
The problem of, however, since information can only be transmitted within " unlatching " time of signal, limit of the spectrum efficiency of system by duty ratio
System.Space light modulation, which refers to, controls dimming level by adjusting the number of spatial activation LED[5], can be in the feelings for keeping signal constant
Reach target dim level under condition, effectively overcome dispersion-shifted problem and brightness adjustment control is simple, but dims control in this method
The precision of system is limited by indoor LED number.Mixing light modulation is come in conjunction with two kinds of dimming modes in above-mentioned three kinds of dimming modes
Realize brightness adjustment control, compared to single space light regulating technology, higher light modulation precision is may be implemented in it[6].But with more
The problem of increase of LED number in LED VLC system, the energy efficiency of system reduces, can not be ignored.
Therefore, it is necessary to study a kind of dimming controlling method of energy-efficient suitable for more LED visible light communication systems
Preferably to take into account illumination and the communication function of VLC.
[1] T.Fath and H.Haas, " the MIMO technology performance of light wireless communication compares in indoor environment " .IEEE
Transactions on Communications[J].2013.61(2):733–742.
[2] F.Zafar, D.Karunatilaka, and R.Parthiban, " the light modulation side applied to visible light communication
Case: research state " .IEEE wireless communication [J] .2015.22 (2): 29-35.
[3] K.H.Loo, Y.M.Lai, S.Tan, and C.K.Tse, " about direct current biasing (DC), pulse width modulation
(PWM) and the double-deck colour stability for driving lower Phosphor converted white light LED " .IEEE Transactions on Power
Electronics[J].2012.27(2):974–984.
[4] H.Wang, and S.Kim, " the adaptive puncturing method of visible light communication light modulation is carried out with polar coordinates code "
.IEEE Photonics Technology Letters[J].2018.30(20):1780–1783.
[5] Y.Yang, Z.Zeng, J.Cheng, and C.Guo, " space of the visible light communication based on light OFDM dims
Scheme " .Optics Express [J] .2016.24 (26): 30254-30263.
[6] Y.Yang, Z.Zeng, J.Cheng, and C.Guo, a kind of " novel mixing light modulation for visible light communication
Control program " .IEEE Photonics Journal [J] .2017.9 (6)
Summary of the invention
In view of the above-mentioned problems, the invention proposes a kind of broad sense brightness adjustment control (Generalized Dimming
Control, GDC) method, pass through Joint regulation pulse amplitude modulation (Pulse Amplitude Modulation, PAM) symbol
Strength range and it is empty when matrix activation element number reach target dim level.This method utilizes PAM symbol and sky simultaneously
When matrix activation index transmission information, effectively taken into account VLC high-speed communication and high-precision light modulation demand.
Specific steps are as follows:
Step 1: the dimming controlling module of the VLC system of the indoor more LED of building, calculates under target dim level, square when empty
The battle array possible value of active element number, and when further calculating sky in matrix each active element optical power；
Transmitting terminal includes N in dimming controlling moduleTA LED, information is to contain NTWhen the sky of × T element matrix be unit into
Row transmission, each NTMatrix includes N when the sky of × TTThe symbolic information that a LED is sent in T time slot.It mixes in light-adjusting module
By the amplitude range of Joint regulation PAM symbol and it is empty when matrix activation element number realize brightness adjustment control, when each empty
There was only N in matrixSA element is activated for transmitting modulation symbol information, remaining element is set as 0.If each in matrix when empty
The normalization light power of active element is ηe, 0 < ηe< 1.Then the dimming level η of GDC system can be indicated are as follows:
Wherein 0 < η < 1.It limits under dimming level, the number of matrix activation element when initialization is emptyIts
InExpression rounds up function.
Step 2: source bit bit string and being transformed to the data blocks of multiple bit informations containing P, each data block is mapped as
Matrix when one sky, the preceding p in each data block1Bit is mapped as a NTEach element and sky in the vector K, K that T × 1 is tieed up
When matrix in each element be corresponding in turn to；
Specific step is as follows:
Step 201, source bit bit string and the data block for being transformed to multiple bit informations containing P include in each data block
Bit number can indicate are as follows:
Wherein,For composite function,For downward bracket function, M is the order of modulation of PAM symbol.
Step 202, using binary system to metric conversion, willBit information be converted to ten into
Integer Z processed.
Z is mapped as one group of number of combinations by step 203Its mapping mathematical expression formula is as follows:
For m=1,2 ..., NS, there is 1≤cm≤NTT。
Step 204, by vector KA element is set as 1, remaining element is set as 0 to get corresponding to Z
Sky when matrix activation index vector KZ。
Step 3: by p remaining in data block2Bit information is modulated to M-PAM symbol, is then linearly become to it
Matrix activation index vector K when changing, then mapping that skyZActive element on, matrix and be mapped to LED array when generating empty
On；
Specific step is as follows:
Step 301, by p2=log2M-bit is modulated to M system PAM symbol x, wherein x ∈ { 1,2 ..., M }.
Step 302 is limited by LED dynamic range, for the limitation for meeting dimming level, needs to carry out line to PAM symbol
Property transformation, mathematic(al) manipulation formula are as follows:
Wherein, IHAnd ILRespectively LED allow by maximum current and minimum current；
Step 304, joint space-time matrix activation index vector KZWith the PAM symbol s after linear transformationxGenerate NTT × 1 is tieed up
Vector S' is indicated are as follows:
S'=KZsx
Vector S' is converted to N by step 305TMatrix S when the sky of × T dimension.
Step 4: LED sends optical signal as unit of matrix when sky, optical signal is visited by the light that optical channel reaches receiving end
It surveys device (Photo Detector, PD), it is contemplated that the electrical-optical-electrical channel gain between different LED and PD is different, and building is based on
The channel matrix of more LED visible light communication systems；
The channel matrix H established in the present invention may be expressed as:
Wherein, hi,jIndicate jth (1≤j≤NT) a (1≤i≤N of LED to i-thR) a PD sighting distance (Line of Sight,
LoS) the DC current gain of link.
Step 5: reception optical signal passes through PD first and is converted into electric signal in receiving end, maximum likelihood detector is utilized
The activation index vector and PAM symbol of matrix when detection judgement receives empty, and the vector and symbol that further judgement is obtained
It is demodulated；
Step 501, receipt signal matrix Y can be obtained by following formula:
Y=HS+W
Wherein,For noise matrix,For set of real numbers, each element is mutually indepedent in matrix W and obeys Gauss
Distribution is expressed asN0For the power of noise.
Receipt signal matrix Y is converted to reception signal phasor Y'=[y by step 5021,y2,…,yT]T, whereinIndicate the reception signal phasor of LED array in t-th of time slot, then system model can be equivalent to:
Above-mentioned model is equivalent are as follows:
Y'=H'S'+W'
Wherein, have to all t=1,2 ..., TIn addition,It is by right
H and full null matrix composition on linea angulata, S' NRT × 1 ties up transmission signal vector, W' NTT × 1 ties up noise vector.
Step 503, when adjudicating empty by maximum likelihood detector joint-detection matrix index vector and PAM symbol, most
Maximum-likelihood detection criteria can indicate are as follows:
Wherein,The estimated value of matrix activation index vector K when for sky；For the s of PAM symbol after intensity modulatedxEstimate
Evaluation；Indicate containing matrix activation vector K at one's leisure set, radix is It indicates comprising all strong
The set of PAM symbol, radix are after degree modulation||·||2Square of representing matrix mould.
Step 504 is obtained using detectionIn nonzero element indexed setExtrapolate estimating for Z
Measured valueIt will by the decimal system-binary translatorBe converted to binary bits information；
It is step 505, rightAntilinear transformation obtains the estimated value x of PAM symbol, is then demodulated into x using PAM demodulator
Binary bits information.
Step 6: bit error rate (Bit Error Ratio, BER) joint circle of computing system；
The channel given for one, if E is the error detection vector of S', then BER joint circle of GDC are as follows:
Wherein, P (S' → E | H') indicates that channel matrix is the pairwise error probability (Conditional under conditions of H'
Pairwise Error Probability, CPEP), n (S')=2p1MKThe total number of all possible forms of expression S', n (S',
E the number of error bits of corresponding pairs of error event (S' → E)) is indicated.
Step 7: calculating N using the method for exhaustionSBER joint circle of corresponding system when taking different value, and then determine
Matrix activation element number N when limiting empty under dimming levelSOptimal selection, to improve the communication reliability of system；
The optimization algorithm of matrix activation element number is as follows when limiting the best sky under dimming level:
Meet:
Successively setStep 2 is repeated to step 6, meter
Calculate different NSBER (the N of corresponding systemS) joint circle, therefrom select the corresponding N of minimum BERSMatrix activation member when being best empty
Plain number.
Advantages of the present invention has:
1. a kind of broad sense dimming controlling method based on more LED visible light communication systems, effectively improves the energy of system
Amount efficiency transmits additional information using the index of matrix activation element when sky；
2. a kind of broad sense dimming controlling method based on more LED visible light communication systems, realizes wide dimming scope and height
The brightness adjustment control of precision；
3. a kind of broad sense dimming controlling method based on more LED visible light communication systems, has effectively taken into account VLC system
Communication and illumination functions；
4. a kind of broad sense dimming controlling method based on more LED visible light communication systems, under the limitation of different dimming levels,
Its reliability is better than traditional dimming controlling method；
Detailed description of the invention
Fig. 1 is the visible light communication system block diagram of more LED in typical indoor scene of the present invention；
Fig. 2 is a kind of flow chart of the broad sense dimming controlling method of the visible light communication system based on more LED of the present invention；
Fig. 3 is the channel model of oriented line of sight link in the present invention；
Fig. 4 is the BER of system when matrix kind activates different number elements in different illumination levels and sky in the present invention
It can curve；
Fig. 5 is that the present invention dims and mix pair for dimming the system BER under 20% and 35% illumination level with conventional digital
Than figure；
Fig. 6 is that the present invention dims and mix pair for dimming the system BER under 50% and 65% illumination level with conventional digital
Than figure；
Specific embodiment
In order to which those skilled in the art is more clearly understood and implements the present invention, below in conjunction with attached drawing with specific
The mode of embodiment elaborates the technical solution of the embodiment of the present invention.
Of the invention a kind of based on more LED visible light communication systems, system realizes block diagram as shown in Figure 1, data bit flow
It is multi-group data block by serioparallel exchange, each data block is divided into two parts, and a part is mapped as the activation of matrix when sky
Index vector, another part are modulated to M-PAM symbol.After linear transformation, joint two parts information obtains matrix when sky, into
And matrix when sky is mapped in LED array and is converted to optical signal, it is transmitted by optical channel, the PD of receiving end converts optical signal
For electric signal, the activation index vector and M-PAM symbol of matrix when then detecting sky using maximum likelihood detector, finally,
To activation index vector demapping, PAM symbol is demodulated to obtain demodulation bit information.
As shown in Fig. 2, specific steps of the invention are as follows:
Step 1: the dimming controlling module of the VLC system of the indoor more LED of building, calculates under the premise of limiting dimming level,
Matrix activation element number possible value when empty, and further calculate the optical power of each active element；
Transmitting terminal includes N in dimming controlling moduleTA LED, information is to contain NTWhen the sky of × T element matrix be unit into
Row transmission includes N in matrix when each emptyTThe symbolic information that a LED is sent in T time slot.Pass through in mixing light-adjusting module
The amplitude range of Joint regulation M-PAM symbol and it is empty when matrix activation element number realize brightness adjustment control, square when each empty
Only N in battle arraySA element is activated for transmitting modulation symbol information, remaining element is set as 0.If each swashing in matrix when empty
The optical power of live element is ηe, 0 < ηe< 1.Then the dimming level η of GDC system can be indicated are as follows:
Wherein 0 < η < 1.It limits under dimming level, the number of active element is in matrix when initialization is emptyWhereinFor the function that rounds up.
Step 2: source bit bit string and being transformed to the data blocks of multiple bit informations containing P, each data block is mapped as
Matrix when one sky, the preceding p in each data block1Bit is mapped as a NTThe vector K that T × 1 is tieed up.Each member in vector K
Element is corresponded with each element in matrix when sky；
Specific step is as follows:
Step 201, source bit bit string and the data block for being transformed to multiple bit informations containing P include in each data block
Bit number can indicate are as follows:
Wherein,For composite function,For downward bracket function.
Step 202, using binary system to metric conversion, willBit information be converted to ten into
Integer Z processed.
Z is mapped as one group of number of combinations by step 203Its mapping mathematical expression formula is as follows:
For m=1,2 ..., NS, there is 1≤cm≤NTT。
Step 204, by vector KA element is set as 1, remaining element is set as 0 to get corresponding to Z
Sky when matrix activation index vector KZ。
Step 3: by p remaining in data block2Bit information is modulated to M-PAM symbol, is then linearly become to it
It changes, matrix activation index vector K when being further mapped to skyZActive element on, matrix and be mapped to LED array when generating empty
On；
Specific step is as follows:
Step 301, by p2=log2M-bit is modulated to M-PAM symbol x, wherein x ∈ { 1,2 ..., M }.
Step 302 is limited by LED dynamic range, for the limitation for meeting dimming level, needs to carry out line to PAM symbol
Property transformation, mathematic(al) manipulation formula are as follows:
Wherein, IHAnd ILRespectively LED allow by maximum current and minimum current.Then each active element is averaged
Electric current I can be indicated are as follows:The optical power of each element can further indicate that are as follows:
Step 304, joint space-time matrix activation index vector KZWith the M-PAM symbol s after linear transformationxGenerate NTT×1
Dimensional vector S' is indicated are as follows:
S'=KZsx
Vector S' is converted to N by step 305TMatrix S when the sky of × T dimension.
Step 4: matrix is sent by LED when empty, the PD of receiving end is reached by optical channel, PD is converted optical signals to
Electric signal, it is contemplated that the electrical-optical-electrical channel gain between different LED and PD is different, constructs the letter based on more LED-VLC systems
Road matrix；
Usually in visible light communication link, the received signal power of LoS link accounts for the overwhelming majority of received signal power.
Therefore, the present invention only considers the visible light channel of LoS link, if hi,jIndicate jth (1≤j≤NT) a LED to i-th (1≤i≤
NR) a PD channel gain, channel matrix H may be expressed as:
As shown in Figure 3, it is assumed that transmitting half-angle when half-power is Φ12, the angle of emergence relative to emission shaft is φ, relative to
The incidence angle of receiving axis is ψ, and receiver visible area half-angle is ΨC, detector area A, d are the distance between LED and PD,
Refractive index is nr, jth (1≤j≤NT) a (1≤i≤N of LED to i-thR) DC current gain of direct projection LoS link that constitutes of a PD is
hi,j, specific expression formula are as follows:
Wherein,For Lambert emission order, g (ψ) is the gain of optical concentrator, expression
Are as follows:
In receiving end, receipt signal matrix Y can be obtained by following formula:
Y=HS+W
Wherein,For noise matrix, wherein each element is mutually indepedent and Gaussian distributed, is expressed asN0For the power of noise.
Step 5: receipt signal matrix to be converted to equivalent received signal vector, then, maximum likelihood detector is utilized
The activation index vector and M-PAM symbol of matrix when detection judgement is empty, and vector that further judgement is obtained and symbol into
Row demodulation；
Step 501, receipt signal matrix Y can be obtained by following formula:
Y=HS+W
Wherein,For noise matrix,For set of real numbers, wherein each element is mutually indepedent and Gaussian distributed
It is expressed asN0For the power of noise.
Receipt signal matrix Y is converted to Y'=[y by step 5021,y2,…,yT]T, whereinIt indicates t-th
The received signal vector of LED array in time slot, then system model can be equivalent to:
Above-mentioned model is equivalent are as follows:
Y'=H'S'+W'
Wherein, have to all t=1,2 ..., TIn addition,It is by right
H and full null matrix composition on linea angulata, S' NRT × 1 ties up transmission signal vector, W' NTT × 1 ties up noise vector.
Step 503, the index information and M-PAM symbol that matrix when adjudicating empty is detected using maximum likelihood detector, most
Maximum-likelihood detection criteria can indicate are as follows:
Wherein,The estimated value of matrix activation index vector K when for sky；For PAM symbol s after intensity modulatedxEstimation
Value；Indicate containing matrix activation vector K at one's leisure set, radix is It indicates comprising all strong
The set of PAM symbol, radix are after degree modulation||·||2Square of representing matrix mould.
Step 504 is obtained using detectionIn nonzero element indexed setExtrapolate estimating for Z
Measured valueIt will by the decimal system-binary translatorBe converted to binary bits information, expression are as follows:
It is step 505, rightAntilinear transformation obtains the estimated value x of PAM symbol x, expression are as follows:
Then x is demodulated into binary bits information using M-PAM demodulator.
Step 6: bit error rate (Bit Error Ratio, BER) joint circle of computing system；
The channel given for one, it is pairs of under conditions of channel matrix is H' if E is the error detection vector of S'
Error probability (Conditional Pairwise Error Probability, CPEP) P (S' → E | H') it can be by following formula meter
It obtains:
Wherein, D Gaussian distributed is expressed asmD=-| | H'(S'-E) | |2,Abbreviation can obtain:
Wherein,BER joint circle of GDC can indicate are as follows:
Wherein, P (S' → E | H') indicates the CPEP, n (S')=2 under conditions of channel matrix is H'p1MKIndicate S' institute
It is possible that the total number of form, n (S', E) indicates the number of error bits of corresponding pairs of error event (S' → E).
Step 7: calculating N using the method for exhaustionSThe corresponding system of every kind of probable value BER joint circle, and then really
Matrix activation element number N when fixed limit sets the tone empty under light levelSOptimal selection, to improve the communication reliability of system；
Successively setStep 2 is repeated to step 6, meter
Calculate different NSBER joint circle of corresponding system therefrom selects the smallest N of BERSWhen as the best sky limited under dimming level
Matrix activation element number.Specific optimization algorithm is as follows:
Meet:
The present invention is at specific dimming level η, and there are optimal NSKeep system BER minimum, Fig. 4 is that different restrictions dim water
Under flat, system BER changes with the change of matrix activation element number when sky.Work as NSWhen smaller, to realize specific dimming level,
The strength range for transmitting constellation symbol is larger, when its strength range is greater than LED normal range of operation, cannot achieve reliable logical
Letter, therefore in this case, system BER is 1.And when the strength range for transmitting symbol meets qualifications, system BER is with NS
Increase and reduce.
GDC and BER simulation performance pair of the tradition DD and HD method in equivalent data rates and dimming level of the invention
Theoretical BER joint circle curve graph than figure and GDC is as shown in Figure 5 and Figure 6, and in legend, DD indicates digital dimming, HD(AD-SD)
Indicate the mixing light modulation for combining space to dim and simulate light modulation, GDCEmulationIndicate the simulation result of GSD, GDCNumerical valueIndicate the BER of GSD
The numerical result of joint circle.When high s/n ratio, GDCEmulationWith GDCNumerical valueIt can be fitted well.In addition, compared with DD and HD, GDC
It can get BER gain under a dimming level, as shown in figure 5, when dimming level is 35%, BER 10-4When, in signal-to-noise ratio
Aspect, compared to HD, GDC can obtain 1dB performance gain；Compared to DD, GDC can obtain the performance gain of 3dB；Such as Fig. 6
It is shown, when dimming level is set as 65%, BER 10-4When, GDC can obtain the gain of 2dB compared to HD and DD.
In conclusion passing through a kind of amplitude range and sky by Joint regulation PAM symbol for implementing the embodiment of the present invention
When matrix activation element number reach the GDC method of target dim level, wide scope, high-precision tune not only may be implemented
Photocontrol, and the communication of high reliability and high energy efficiency may be implemented；Compared to existing DD and HD, the present invention is effectively prevented from
The disadvantage that information transmission form is single, energy efficiency is low, can obtain bigger BER performance gain.
The above is a preferred embodiment of the present invention, it is noted that for those skilled in the art
For, various improvements and modifications may be made without departing from the principle of the present invention, these improvements and modifications are also considered as
Protection scope of the present invention.
Claims (1)
1. a kind of broad sense dimming controlling method based on more LED visible light communication systems, specific implementation step are as follows:
Step 1: the dimming controlling module of the VLC system of the indoor more LED of building, calculates under target dim level, matrix swashs when empty
The possible value of live element number, and further calculate the optical power of each active element；
Transmitting terminal includes N in dimming controlling moduleTA LED, information is with NTMatrix is that unit is transmitted when the sky of × T element,
Each NTMatrix includes N when the sky of × TTThe symbolic information that a LED is sent in T time slot, when mixing each empty in light-adjusting module
There was only N in matrixSA element is activated for transmitting modulation symbol information, remaining element is set as 0, if each in matrix when empty
The normalization light power of active element is ηe, 0 < ηeThe dimming level η of < 1, GDC system can be indicated are as follows:
Wherein 0 < η < 1, initialization Expression rounds up function；
Step 2: source bit information serial to parallel conversion first is multiple data blocks, the data block of each bit information containing P is mapped as
Matrix when one sky, then, by the preceding p in each data block1Bit is mapped as a NTThe vector K that T × 1 is tieed up is for indicating
When each empty in matrix active element serial number；
Specific step is as follows:
Step 201, source bit bit string and the data block for being transformed to multiple bit informations containing P, the ratio for including in each data block
Special number can indicate are as follows:
Wherein,For composite function,For downward bracket function, M is the order of modulation of PAM symbol；
Step 202, using binary system to metric conversion, willIt is whole that bit information is converted to the decimal system
Number Z；
Z is mapped as one group of number of combinations by step 203Its mapping mathematical expression formula is as follows:
For m=1,2 ..., NS, there is 1≤cm≤NTT；
Step 204, by vector KA element is set as 1, when remaining element is set as 0 to get sky corresponding to Z
Matrix activation index vector KZ；
Step 3: by p remaining in data block2Bit information is modulated to M-PAM symbol, then carries out linear transformation to it, is inciting somebody to action
Matrix activation index vector K when it is mapped to skyZActive element on, matrix and be mapped in LED array when generating empty；
Specific step is as follows:
Step 301, by p2=log2M-bit is modulated to M system PAM symbol x, wherein x ∈ { 1,2 ..., M }；
Step 302 is limited by LED dynamic range, for the limitation for meeting dimming level, needs linearly to become PAM symbol
It changes, mathematic(al) manipulation formula are as follows:
Wherein, IHAnd ILRespectively LED allow by maximum current and minimum current；
Step 304, joint space-time matrix activation index vector KZWith the PAM symbol s after linear transformationxGenerate NTThe dimensional vector of T × 1
S' is indicated are as follows:
S'=KZsx
Vector S' is converted to N by step 305TMatrix S when the sky of × T dimension；
Step 4: matrix is sent by LED when empty, the PD of receiving end is reached by optical channel, it is contemplated that between different LED and PD
Electrical-optical-electrical channel gain it is different, construct the channel matrix based on more LED-VLC systems；
The channel matrix H established in the present invention may be expressed as:
Wherein, hi,jIndicate jth (1≤j≤NT) a (1≤i≤N of LED to i-thR) a PD sighting distance (Line of Sight, LoS) chain
The DC current gain on road；
Step 5: reception optical signal passes through PD first and is converted into electric signal in receiving end, detected using maximum likelihood detector
The activation index vector and PAM symbol of matrix when judgement receives empty, and the vector and symbol that further obtain to judgement carry out
Demodulation；
Step 501, receipt signal matrix Y can be obtained by following formula:
Y=HS+W
Wherein,For noise matrix,For set of real numbers, in matrix W, each element is mutually indepedent and Gaussian distributed table
It is shown asN0For the power of noise；
Receipt signal matrix Y is converted to reception signal phasor Y'=[y by step 5021,y2,…,yT]T, wherein
Indicate the reception signal phasor of LED array in t-th of time slot, then system model can be equivalent to:
Above-mentioned model is equivalent are as follows:
Y'=H'S'+W'
Wherein, have to all t=1,2 ..., TIn addition,It is by diagonal line
On H and full null matrix composition, S' NRT × 1 ties up transmission signal vector, W' NTT × 1 ties up noise vector；
Step 503, when adjudicating empty using maximum likelihood detector joint-detection matrix index vector and PAM symbol, it is maximum seemingly
Right detection criteria can indicate are as follows:
Wherein,The estimated value of matrix activation index vector K when for sky；For PAM symbol s after intensity modulatedxEstimated value；
Indicate containing matrix activation vector K at one's leisure set, radix is It indicates to include all intensity modulateds
The set of PAM symbol, radix are afterwards||·||2Square of representing matrix mould；
Step 504 is obtained using detectionIn nonzero element indexed setExtrapolate the estimated value of ZIt will by the decimal system-binary translatorBe converted to binary bits information；
It is step 505, rightAntilinear transformation obtains the estimated value x of PAM symbol, then using PAM demodulator by x be demodulated into two into
Bit information processed；
Step 6: bit error rate (Bit Error Ratio, BER) joint circle of computing system；
The channel given for one, if E is the error detection vector of S', then BER joint circle of GDC are as follows:
Wherein, P (S' → E | H') indicates pairwise error probability (Conditional under conditions of channel matrix is H'
Pairwise Error Probability, CPEP), n (S')=2p1MKThe total number of all possible forms of expression S', n (S',
E the number of error bits of corresponding pairs of error event (S' → E)) is indicated；
Step 7: calculating N using the method for exhaustionSBER joint circle of corresponding system when taking different value, and then determine to limit and adjust
Matrix activation element number N when empty under light levelSOptimal selection, to improve the communication reliability of system；
The optimization algorithm of matrix activation element number is as follows when limiting the best sky under dimming level:
Meet:
Successively setStep 2 is repeated to step 6, is calculated different
NSBER (the N of corresponding systemS) joint circle, therefrom select the corresponding N of minimum BERSMatrix activation element number when being best empty.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910824766.4A CN110474684B (en) | 2019-09-02 | 2019-09-02 | Generalized dimming control method based on multi-LED visible light communication system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910824766.4A CN110474684B (en) | 2019-09-02 | 2019-09-02 | Generalized dimming control method based on multi-LED visible light communication system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110474684A true CN110474684A (en) | 2019-11-19 |
| CN110474684B CN110474684B (en) | 2020-11-27 |
Family
ID=68514661
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910824766.4A Active CN110474684B (en) | 2019-09-02 | 2019-09-02 | Generalized dimming control method based on multi-LED visible light communication system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110474684B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112737695A (en) * | 2020-12-04 | 2021-04-30 | 东南大学 | Adaptive symbol set design method based on generalized spatial modulation |
| CN113098573A (en) * | 2021-03-16 | 2021-07-09 | 北京邮电大学 | Hybrid dimming method combining antenna selection and precoding |
| CN114285472A (en) * | 2021-12-20 | 2022-04-05 | 北京邮电大学 | UPSOOK modulation method with forward error correction based on mobile phone camera |
Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013064835A2 (en) * | 2011-11-04 | 2013-05-10 | The University Court Of The University Of Edinburgh | Communication apparatus and method |
| KR101470755B1 (en) * | 2013-09-06 | 2014-12-08 | 영남대학교 산학협력단 | Method for Multiple-Level Transmission in a Wireless light Communication System |
| CN106130638A (en) * | 2016-08-20 | 2016-11-16 | 华南理工大学 | PAM Yu MPPM dual modulation method and system for visible light communication |
| CN107276671A (en) * | 2017-06-21 | 2017-10-20 | 中国科学技术大学 | A kind of method for the indoor visible light communication system for optimizing spatial modulation |
| US20170346559A1 (en) * | 2016-05-26 | 2017-11-30 | The Florida International University Board Of Trustees | System and method for visible light communications with multi-element transmitters and receivers |
| US9900094B2 (en) * | 2015-10-05 | 2018-02-20 | Electronics And Telecommunications Research Institute | Visible-light wireless communication apparatus and method using the same |
| US20180069628A1 (en) * | 2016-09-02 | 2018-03-08 | Futurewei Technologies, Inc. | Method of Dimming for Visible Light Communications |
| CN107949997A (en) * | 2015-04-30 | 2018-04-20 | 法国矿业电信学校联盟 | Space Time Coding for communication system |
| CN108366031A (en) * | 2017-08-14 | 2018-08-03 | 广东顺德中山大学卡内基梅隆大学国际联合研究院 | In conjunction with the reversed polarity multi-pulse position modulation optical OFDM system of brightness adjustment control |
| CN108512801A (en) * | 2018-04-09 | 2018-09-07 | 山东大学 | A kind of visible light communication modulator approach and its realization system based on carrier index modulation |
| US20180302157A1 (en) * | 2017-04-12 | 2018-10-18 | Futurewei Technologies, Inc. | Dimming control for orthogonal frequency division multiplexing-based visible light communication |
| CN109004980A (en) * | 2018-08-01 | 2018-12-14 | 深圳清华大学研究院 | Visible light communication mixing light-dimming method and device based on generalized space modulation |
| CN109617603A (en) * | 2019-01-04 | 2019-04-12 | 清华大学 | Visible light communication mixing light-dimming method and device based on index modulation |
| CN109981178A (en) * | 2019-03-12 | 2019-07-05 | 山东大学 | The working method of generalized spatial modulation system based on gamut keying modulation |
-
2019
- 2019-09-02 CN CN201910824766.4A patent/CN110474684B/en active Active
Patent Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013064835A2 (en) * | 2011-11-04 | 2013-05-10 | The University Court Of The University Of Edinburgh | Communication apparatus and method |
| KR101470755B1 (en) * | 2013-09-06 | 2014-12-08 | 영남대학교 산학협력단 | Method for Multiple-Level Transmission in a Wireless light Communication System |
| CN107949997A (en) * | 2015-04-30 | 2018-04-20 | 法国矿业电信学校联盟 | Space Time Coding for communication system |
| US9900094B2 (en) * | 2015-10-05 | 2018-02-20 | Electronics And Telecommunications Research Institute | Visible-light wireless communication apparatus and method using the same |
| US20170346559A1 (en) * | 2016-05-26 | 2017-11-30 | The Florida International University Board Of Trustees | System and method for visible light communications with multi-element transmitters and receivers |
| CN106130638A (en) * | 2016-08-20 | 2016-11-16 | 华南理工大学 | PAM Yu MPPM dual modulation method and system for visible light communication |
| US20180069628A1 (en) * | 2016-09-02 | 2018-03-08 | Futurewei Technologies, Inc. | Method of Dimming for Visible Light Communications |
| US20180302157A1 (en) * | 2017-04-12 | 2018-10-18 | Futurewei Technologies, Inc. | Dimming control for orthogonal frequency division multiplexing-based visible light communication |
| CN107276671A (en) * | 2017-06-21 | 2017-10-20 | 中国科学技术大学 | A kind of method for the indoor visible light communication system for optimizing spatial modulation |
| CN108366031A (en) * | 2017-08-14 | 2018-08-03 | 广东顺德中山大学卡内基梅隆大学国际联合研究院 | In conjunction with the reversed polarity multi-pulse position modulation optical OFDM system of brightness adjustment control |
| CN108512801A (en) * | 2018-04-09 | 2018-09-07 | 山东大学 | A kind of visible light communication modulator approach and its realization system based on carrier index modulation |
| CN109004980A (en) * | 2018-08-01 | 2018-12-14 | 深圳清华大学研究院 | Visible light communication mixing light-dimming method and device based on generalized space modulation |
| CN109617603A (en) * | 2019-01-04 | 2019-04-12 | 清华大学 | Visible light communication mixing light-dimming method and device based on index modulation |
| CN109981178A (en) * | 2019-03-12 | 2019-07-05 | 山东大学 | The working method of generalized spatial modulation system based on gamut keying modulation |
Non-Patent Citations (2)
| Title |
|---|
| TENGJIAO WANG ; FANG YANG ; LING CHENG ; JIAN SONG: "Generalized Spatial Modulation Based Hybrid Dimming Scheme for Visible Light Communication", 《2018 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM)》 * |
| 吴颖杰，徐洪波，康瑞: "可见光通信中有照明限制的广义空间调制算法", 《计算机工程》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112737695A (en) * | 2020-12-04 | 2021-04-30 | 东南大学 | Adaptive symbol set design method based on generalized spatial modulation |
| CN112737695B (en) * | 2020-12-04 | 2021-10-08 | 东南大学 | Adaptive symbol set design method based on generalized spatial modulation |
| CN113098573A (en) * | 2021-03-16 | 2021-07-09 | 北京邮电大学 | Hybrid dimming method combining antenna selection and precoding |
| CN114285472A (en) * | 2021-12-20 | 2022-04-05 | 北京邮电大学 | UPSOOK modulation method with forward error correction based on mobile phone camera |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110474684B (en) | 2020-11-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110474684A (en) | A kind of broad sense dimming controlling method based on more LED visible light communication systems | |
| Zafar et al. | Dimming schemes for visible light communication: the state of research | |
| CN107342823A (en) | Joint color and shift in intensity key modulation method for visible light communication system | |
| CN104467964B (en) | A kind of traffic rate optimization method of indoor visible light communication | |
| Das et al. | Color-independent VLC based on a color space without sending target color information | |
| CN112910554B (en) | CSK constellation bit mapping method | |
| CN104753595B (en) | The modulator approach of brightness regulation is supported in a kind of indoor visible light communication system | |
| CN108540180A (en) | A kind of polychrome MIMO-VLC Bit and power allocations Constellation Design scheme | |
| Jha et al. | Challenges and potentials for visible light communications: State of the art | |
| Guo et al. | Constant weight space-time codes for dimmable MIMO-VLC systems | |
| Idris et al. | A survey of modulation schemes in visible light communications | |
| Chatterjee et al. | Daylight integrated indoor VLC architecture: an energy‐efficient solution | |
| CN105553554B (en) | Visible light communication signal constellation (in digital modulation) design method, apparatus and system | |
| Knobloch | Channel gain and frame error rate for optical street lighting communication | |
| CN108809382A (en) | Multiuser MIMO visible light communication method based on selection light modulation and precoding | |
| CN108494485A (en) | The mapping method of generalized space modulation spectrum efficiency in a kind of raising visible light communication | |
| CN109981178A (en) | The working method of generalized spatial modulation system based on gamut keying modulation | |
| Yi et al. | Performance improvement of dimmable VLC system with variable pulse amplitude and position modulation control scheme | |
| Wang et al. | Antenna selection based dimming scheme for indoor MIMO visible light communication systems utilizing multiple lamps | |
| CN107181531B (en) | Bit mapping method when LED number is any in light spatial modulation communication system | |
| Mir et al. | Non-linearity of LEDs for VLC IoT applications | |
| CN110098871A (en) | The working method of indoor VLC multithread spatial modulation system based on color space | |
| Reguera et al. | Efficient and low-complexity rate and dimming control of VLC for industrial IoT applications | |
| Hong et al. | CSK hopping pattern model for visible light communication networks | |
| Wang et al. | A novel dimming scheme for indoor MIMO visible light communication based on antenna selection |
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 |