CN107769851A - A kind of LED localization methods and system based on mixing OFDM - Google Patents
A kind of LED localization methods and system based on mixing OFDM Download PDFInfo
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- 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
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- 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
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- 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
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- 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
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- 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
- H04B10/66—Non-coherent receivers, e.g. using direct detection
- H04B10/69—Electrical arrangements in the receiver
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management
- H04W64/003—Locating users or terminals or network equipment for network management purposes, e.g. mobility management locating network equipment
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Abstract
The invention discloses a kind of LED localization methods and system based on mixing OFDM, this method is combined mixing OFDM LED location algorithms with system, modulates strange carrier wave using ACO OFDM, PAM DMT modulate the imaginary part of even carrier wave, and the coordinate of receiver is determined using RSS.The LED localization methods and system based on mixing OFDM of the present invention, improves the positioning precision under the influence of multi-path jamming, while improve transmission rate and the availability of frequency spectrum.
Description
Technical field
In terms of the present invention relates to position positioning field, more particularly to LED positioning, more specifically to based on mixing
OFDM LED localization methods and system.
Background technology
Location-based service determines the actual geographic position of mobile subscriber by the cooperation of mobile terminal and wireless network, from
And provide user's information service related to position of needs.Global positioning system (Global Satellite
Positioning, GPS) it is the alignment system being most widely used at present, but satellite-signal can not penetrate building, and it is indoor
There is serious multipath and non line of sight interference in environment, be difficult to position indoors to improve the precision of indoor positioning, people
Employ infrared ray positioning, ultrasonic wave positioning, radio frequency identification positioning etc. technology, but traditional indoor positioning technologies system into
Sheet, stability, positioning precision etc. can not fully meet the demand of user.With light emitting diode (light-emitting-
Diode, LED) lighting engineering development, it is seen that optical communication technique (Visible Light Communication, VLC) is also
To development, the indoor positioning airmanship based on visible light communication becomes the focus of research.With traditional radio frequency positioning and its
Its wireless location technology is compared, and the indoor positioning based on LED visible light communication has high transmission power, positioning precision height, used
Occasion is wide, without electromagnetic interference and the advantages that save the energy.
But in actual applications, LED alignment systems can all be influenceed by multi-path jamming in indoor environment, periodical
《ournal of Lightwave Technology》In the article that the 10th periodical of volume 34 in 2016 is stepped on《Impact of
Multipath Reflections on the Performance of Indoor Visible Light Positioning
Systems》It has studied influence of the multi-path jamming to positioning precision, the results showed that multi-path jamming can substantially reduce positioning precision, institute
Orthogonal frequency division multiplexis (orthogonal frequency division in location algorithm need to be considered with multi-path jamming
Multiplexing, OFDM) inter-symbol interference problem caused by resistance multi-path jamming is widely used in always, and improve transmission speed
Rate.Unlike conventional radio frequency radio communication, VLC use intensities modulation directly detection (intensity-modulation
Direct-detection, IM/DD), it is desirable to the transmission signal using light intensity as carrier must be nonnegative real number.Direct current biasing light is just
Hand over frequency division multiplexing (direct-current-biased optical OFDM, DCO-OFDM) non-by being superimposed direct current biasing acquisition
Negative transmission signal, less direct current biasing can cause larger clipped noise, and larger direct current biasing can then reduce power effect
Rate.Asymmetric amplitude limit light OFDM (asymmetrically clipped optical OFDM, ACO-OFDM) is only adjusted
Make strange carrier wave, pulse amplitude modulation-Discrete Multitone Modulation (pulse amplitude modulated discrete
Multitone, PAM-DMT) carrier wave imaginary part is only modulated, both of which obtains non-negative transmission signal, clipped noise by null value amplitude limit
Only influence unmodulated carrier part, but null value amplitude limit makes transmitting terminal half energy charge cause ACO- in unmodulated carrier part
OFDM and PAM-DMT has 3dB performance loss compared to traditional bipolarity OFDM.Periodical《Journal of Lightwave
Technology》In the article that the 7th periodical of volume 31 in 2013 is stepped on《Armstrong J.Comparison of ACO-OFDM,
DCO-OFDM and ADO-OFDM in IM/DD Systems》Propose a kind of by ACO-OFDM and DCO-OFDM mixed transports
Method, improve transmission rate.In order to further improve the availability of frequency spectrum and reduce transmission complexity, periodical《Journal
of Optical Communications and Networking》In the article that the 4th periodical of volume 6 in 2014 is stepped on《Hybrid
Asymmetrically Clipped OFDM-Based IM/DD Optical Wireless System》Propose ACO-
The method of OFDM and PAM-DMT mixed transports.
Current most of LED alignment systems all use LED, and as emitter, the photo-detector being fixed in target is used as and connect
Receipts machine, and the coordinate of receiver is calculated using the distance between transceiver, the acquisition methods of the distance have the reception time
(time-of-arrival, TOA) (refers to periodical《Journal of Lightwave Technology》In 2013 the 31st
Roll up the article that the 20th periodical is stepped on《Accuracy of Time-of-Arrival Based Ranging Using Visible
Light With Application in Indoor Localization Systems》), receive the time difference (time-
Difference-arrival, TDOA) (refer to periodical《IEEE Transactions on Consumer
Electronics》In the article that the 4th periodical of volume 57 in 2011 is stepped on《TDOA-based optical wireless indoor
localization using LED ceiling lamps》) and reception signal intensity (received-signal-
Strength, RSS) (refer to periodical《IEEE Transactions on Systems,Man,and Cybernetics,
Part C(Applications and Reviews)》In the article that the 6th periodical of volume 37 in 2007 is stepped on《Survey of
Wireless Indoor Positioning Techniques and Systems》And periodical《Optics Express》In
The article that the 16th periodical of volume 23 in 2015 is stepped on《Exploring the effect of diffuse reflection on
indoor localization systems based on RSSI-VLC》) three kinds.The energy attenuation that RSS passes through transmission signal
Carry out estimated distance, be widely used because its principle is simple.Periodical《Optical Engineering》In 2016 volume 55
The article that 5th periodical is stepped on《Indoor location estimation with optical-based orthogonal
frequency division multiplexing communications》Propose and combined ACO-OFDM with alignment system
Algorithm, but its positioning precision need further to improve, and it has the transmitting terminal half of ACO-OFDM system generally existings
Energy charge can produce 3dB performance loss the unmodulated carrier part the problem of.
The content of the invention
For above-mentioned technical problem, the invention provides a kind of LED alignment systems and method based on mixing OFDM.
According to the wherein one side of the present invention, the present invention is its technical problem of solution, there is provided one kind is based on mixing OFDM
LED localization methods, include following step：
S1, multiple LED transmitters respectively by respective ACO-OFDM signals together with PAM-DMT Signal averagings after distinguish
Send；
Wherein, ACO-OFDM signals are obtained by following methods：Input signal is very being carried by M members quadrature amplitude modulation
On ripple, complex data that generation length is N/4, even carrier wave whole zero setting, first and the N/2 subcarrier also zero setting, Ran Houzhuan
It is changed to after string code carries out clipping operation and obtains, wherein, M is the size of planisphere, and N is sub-carrier number；
PAM-DMT signals are obtained by following methods：Input signal is modulated at using M member pulse amplitude modulating methods
In the imaginary part of even carrier wave, strange carrier wave whole zero setting, it is then converted into obtaining after string code carries out clipping operation；
Input signal includes coordinate of the emitter in horizontal plane；
S2, receiver estimate PAM-DMT signals respectively according to the signal of each emitter received, and according to respectively
The PAM-DMT signals estimated reconstruct PAM-DMT signals respectively；
S3, receiver calculate receiver according to the PAM-DMT signals reconstructed of each emitter and corresponding coordinate
Coordinate in a horizontal plane.
Further, in the step S2 of the LED localization methods of the present invention, the PAM-DMT signals of each emitter are estimated
Calculation method includes following step：
S21, the signal received to receiver obtain the anti-ACO-OFDM computings of odd sequence progress after carrying out Fourier transformation,
The ACO-OFDM signals estimated；
S22, according to estimation ACO-OFDM signals, the clipped noise on even carrier wave is calculated；
S23, calculating obtain even sequence and the limit on even carrier wave after the signal that receiver receives is carried out into Fourier transformation
The difference of amplitude and noise sound, take estimated value of the imaginary part of difference as PAM-DMT signals.
Further, in the step S3 of the LED localization methods of the present invention, the coordinate of receiver in a horizontal plane is under
Formula is stated to be calculated：
Q=(MTM)-1MTN,
Wherein,And Q is required receiver coordinate, Xi、
YiFor the abscissa and ordinate of the horizontal plane of i-th of emitter, riFor the horizontal range between receiver and i-th of emitter,
I=1,2 ..., n, n be emitter number, riIt is calculated by following formula：
In formula, PtAveraged for the power of PAM-DMT signals after i-th of LED reconstruct, PriFor i-th LED's
The average value of the transmission power of PAM-DMT signals, lambert's exponent number are m=-ln2/ln (cos Ψ1/2), Ψ1/2It is to be used to launch letter
Number LED half-power angle, A is the physical area of the photodetector for reception signal, DiLaunch for receiver and i-th
The distance between machine, θiFor i-th lamp angle of departure,Incidence angle for i-th of receiver relative to its normal direction,For
The propagation coefficient of i-th of LED optical filter,It is the gain of i-th of LED light concentrator, size is by the following formula of formula
It is determined that：
Wherein, ΦcFor half angle at light concentrator visual angle, n is the refractive index of light concentrator.
Further, in the LED localization methods of the present invention, the signal direction of the launch of emitter and the signal of receiver connect
Debit in perpendicular to ground, the coordinate of receiver in a horizontal plane by following formula to being calculated：
Q=(MTM)-1MTN,
Wherein,And Q is required receiver coordinate, Xi、
YiFor the abscissa and ordinate of the horizontal plane of i-th of emitter, riFor the horizontal range between receiver and i-th of emitter,
I=1,2 ..., n, n be emitter number, riIt is calculated by following formula：
Wherein, C is preset constant, and its size meets
In formula, PtAveraged for the power of PAM-DMT signals after i-th of LED reconstruct, PriFor i-th LED's
The average value of the transmission power of PAM-DMT signals, lambert's exponent number are m=-ln2/ln (cos Ψ1/2), Ψ1/2It is to be used to launch letter
Number LED half-power angle, A is the physical area of the photodetector for reception signal, DiLaunch for receiver and i-th
The distance between machine, θiFor i-th lamp angle of departure,Incidence angle for i-th of receiver relative to its normal direction,For
The propagation coefficient of i-th of LED optical filter, hiFor vertical range of i-th of receiver between emitter,It is i-th
The gain of individual LED light concentrator, size are determined by the following formula of formula：
Wherein, ΦcFor half angle at light concentrator visual angle, n is the refractive index of light concentrator.
Further, in the LED localization methods of the present invention, input signal also includes the transmitter identity identification information,
To enable the receiver for receiving the identity identification information to make a distinction the coordinate of each emitter.
According to another aspect of the present invention, the present invention additionally provides a kind of based on mixing OFDM to solve its technical problem
LED alignment systems, comprising：
Multiple control modules, it is located at is loaded on multiple emitters respectively, for controlling the multiple emitter to distinguish respectively
Respective ACO-OFDM signals are sent respectively afterwards together with PAM-DMT Signal averagings；
Wherein, ACO-OFDM signals are obtained by the first transmitter unit, and the first transmitter unit is used to input signal passing through M
First quadrature amplitude modulation is on strange carrier wave, complex data that generation length is N/4, even carrier wave whole zero setting, first and N/2
Subcarrier also zero setting, it is then converted into obtaining after string code carries out clipping operation, wherein, M is the size of planisphere, and N is subcarrier
Number；
PAM-DMT signals are obtained by the second transmitter unit, and the second transmitter unit is used to use M members pulse amplitude modulation side
Input signal is modulated in the imaginary part of even carrier wave by method, strange carrier wave whole zero setting, after being then converted into string code progress clipping operation
Obtain；
Input signal includes coordinate of the emitter in horizontal plane；
Signal reconstruction module, on receiver, for being estimated respectively according to the signal of each emitter received
PAM-DMT signals, and PAM-DMT signals are reconstructed according to the PAM-DMT signals estimated respectively respectively；
Position computation module, on receiver, for reconstructing PAM-DMT signals and correspondingly according to each emitter
Coordinate calculate receiver coordinate in a horizontal plane.
Further, the signal reconstruction module of LED alignment systems of the invention estimates each transmitting using following units
The PAM-DMT signals of machine：
ACO-OFDM signal estimation units, the signal for being received to receiver obtain odd-order after carrying out Fourier transformation
Row carry out anti-ACO-OFDM computings, the ACO-OFDM signals estimated；
Even carrier wave clipped noise computing unit, for according to estimation ACO-OFDM signals, the limit on even carrier wave to be calculated
Amplitude and noise sound；
PAM-DMT signal estimation units, obtained after the signal that receiver receives is carried out into Fourier transformation for calculating
The difference of even sequence and the clipped noise on even carrier wave, takes estimated value of the imaginary part of difference as PAM-DMT signals.
Further, in the position computation module of LED alignment systems of the invention, the coordinate of receiver in a horizontal plane leads to
Following formula are crossed to be calculated：
Q=(MTM)-1MTN,
Wherein,And Q is required receiver coordinate, Xi、
YiFor the abscissa and ordinate of the horizontal plane of i-th of emitter, riFor the horizontal range between receiver and i-th of emitter,
I=1,2 ..., n, n be emitter number, riIt is calculated by following formula：
In formula, PtAveraged for the power of PAM-DMT signals after i-th of LED reconstruct, PriFor i-th LED's
The average value of the transmission power of PAM-DMT signals, lambert's exponent number are m=-ln2/ln (cos Ψ1/2), Ψ1/2It is to be used to launch letter
Number LED half-power angle, A is the physical area of the photodetector for reception signal, DiLaunch for receiver and i-th
The distance between machine, θiFor i-th lamp angle of departure,Incidence angle for i-th of receiver relative to its normal direction,For
The propagation coefficient of i-th of LED optical filter,It is the gain of i-th of LED light concentrator, size is by the following formula of formula
It is determined that：
Wherein, ΦcFor half angle at light concentrator visual angle, n is the refractive index of light concentrator.
Further, in LED alignment systems of the invention, the signal direction of the launch of emitter and the signal of receiver receive
Direction is calculated in perpendicular to ground, the coordinate of receiver in a horizontal plane by following formula：
Q=(MTM)-1MTN,
Wherein,And Q is required receiver coordinate, Xi、
YiFor the abscissa and ordinate of the horizontal plane of i-th of emitter, riFor the horizontal range between receiver and i-th of emitter,
I=1,2 ..., n, n be emitter number, riIt is calculated by following formula：
Wherein, C is preset constant, and its size meets
In formula, PtAveraged for the power of PAM-DMT signals after i-th of LED reconstruct, PriFor i-th LED's
The average value of the transmission power of PAM-DMT signals, lambert's exponent number are m=-ln2/ln (cos Ψ1/2), Ψ1/2It is to be used to launch letter
Number LED half-power angle, A is the physical area of the photodetector for reception signal, DiLaunch for receiver and i-th
The distance between machine, θiFor i-th lamp angle of departure,Incidence angle for i-th of receiver relative to its normal direction,For
The propagation coefficient of i-th of LED optical filter, hiFor vertical range of i-th of receiver between emitter,It is i-th
The gain of individual LED light concentrator, size are determined by the following formula of formula：
Wherein, ΦcFor half angle at light concentrator visual angle, n is the refractive index of light concentrator.
Further, in LED alignment systems of the invention, input signal also includes the transmitter identity identification information, with
The receiver for receiving the identity identification information is made a distinction the coordinate of each emitter.
The invention discloses a kind of LED localization methods and system based on mixing OFDM, this method is combined mixing with system
OFDM LED location algorithms, strange carrier wave is modulated using ACO-OFDM, PAM-DMT modulates the imaginary part of even carrier wave, and true using RSS
Determine the coordinate of receiver.The LED localization methods and system based on mixing OFDM of the present invention, is improved under the influence of multi-path jamming
Positioning precision, while improve transmission rate and the availability of frequency spectrum.
Brief description of the drawings
Below in conjunction with drawings and Examples, the invention will be further described, in accompanying drawing：
Fig. 1 is the flow chart of an embodiment of the LED localization methods based on mixing OFDM of the present invention；
Fig. 2 is the use state figure of the LED localization methods based on mixing OFDM in Fig. 1 of the invention.
Embodiment
In order to which technical characteristic, purpose and the effect of the present invention is more clearly understood, now compares accompanying drawing and describe in detail
The embodiment of the present invention.
As shown in Figure 1, 2, the flow of an embodiment of its LED localization method based on mixing OFDM respectively of the invention
Figure and Fig. 1 in based on mixing OFDM LED localization methods use state figure.This method is particularly suitable for use in indoor positioning, under
Fig. 2 will be combined by stating illustrates to the LED localization methods based on mixing OFDM in Fig. 1.
In Fig. 2, cuboid is one long 6 meters, wide 6 meters, high 4.2 meters of room, has four LEDs on the ceiling in room
Bubble, each bulb optical sender independent as one, launch unique ID (identification) codings and position coordinates, this implementation
The position coordinates of example represents that x represents the coordinate of x-axis using coordinate (x, y, z), and y represents the coordinate of y-axis, and z represents the coordinate of z-axis,
Except the coordinate (x, y) included in horizontal plane outside, also comprising height coordinate z, each positional information be respectively (2,2,4.2), (2,4,
4.2), (4,2,4.2) and (4,4,4.2).In other embodiments, height coordinate can not be sent by emitter to reception
Machine, and directly defaulted in using default mode in emitter.
S1, in each transmitter terminal, the system modulates strange carrier wave using ACO-OFDM, and PAM-DMT modulates the void of even carrier wave
Portion, two paths of signals are generated respectively, and (periodical is referred to then in conjunction with being transmitted for a signal《Journal of Optical
Communications and Networking》In the article that the 4th periodical of volume 6 in 2014 is stepped on《Hybrid
Asymmetrically Clipped OFDM-Based IM/DD Optical Wireless System》)。
Specifically, the mode that obtains of ACO-OFDM signals is：Input comprising emitter ID codings and position coordinates is believed
Number it is modulated at by M members quadrature amplitude modulation (M-ary quadrature amplitude modulation, M-QAM) on strange carrier wave,
The complex data that generation length is N/4, even carrier wave whole zero setting, wherein, M is the size of planisphere, and N is sub-carrier number.In addition,
In order to meet Hermitian symmetric rule to ensure output signal to be true, first and the N/2 subcarrier also zero setting.Now, it is raw
Into signalFor N point quick Fouriers inverse transformation (inverse fast
Fourier transform, IFFT) input signal, wherein ()*The complex conjugate of vector is represented, string code is then converted into and enters
ACO-OFDM signals are obtained after row clipping operation.And PAM-DMT signals then use M member pulse amplitude modulations (M-arypulse
Amplitude modulation, PAM) input signal is modulated in the imaginary part of even carrier wave by method, strange carrier wave whole zero setting,
IFFT input signal isIt is then converted into string code and carries out clipping operation
After obtain PAM-DMT signals.How to be converted to string code and how to carry out clipping operation and belong to techniques well known, here not
Repeat again.
After clipping operation obtains non-negative signal, this two parts of signals is superimposed, and inserts cyclic prefix
(cyclic prefix, CP), eventually enter into optical channel transmission.
S2, in receiver end, reception signal carries out Fourier transformation (fast Fourier after CP is removed
Transform, FFT), respectively obtain even sequence and odd sequence, even-order corresponding to each emitter and be classified as reven、caco、cpam、
nevenSum, odd-order are classified as rodd、caco、cpam、noddSum, wherein roddAnd revenRespectively ACO-OFDM and PAM-DMT signals,
cacoAnd cpamRespectively ACO-OFDM and PAM-DMT clipped noise, noddAnd nevenRepresent the additive Gaussian white noise in optical channel
Sound (additive white Gaussian nose, AWGN).
Then anti-ACO-OFDM computings, the ACO-OFDM signals estimated are carried out to odd sequence.
Further according to estimation ACO-OFDM signals, the clipped noise on even carrier wave is calculated.This step belongs to this area public affairs
Know general knowledge.
The difference of even sequence and the clipped noise on even carrier wave is calculated again, takes the imaginary part of difference as PAM-DMT signals
Estimated value.
By PAM technique, the estimating signal restructural goes out PAM-DMT signals, and the reconstruction signal eliminates PAM-DMT signals
The clipped noise of the middle real part for influenceing even carrier wave, estimation precision is higher, and final according to the PAM-DMT signals reconstructed and each
The coordinate of individual emitter calculates receiver coordinate.Because receiver is located at ground, the coordinate of its z-axis is 0, therefore only needs to count
Calculate the x-axis of receiver and the coordinate of y-axis.
Each emitter, which corresponds to parameter, can obtain the x-axis of one group of receiver and the coordinate of y-axis, with any one group of hair
Penetrate one group of receiver of parameter acquiring corresponding to machine x-axis and y-axis coordinate concrete implementation mode it is as follows.
Obtain the P that averages of the power of the PAM-DMT signals of i-th of LED after reconstructt, i-th LED PAM-DMT
The average value P of the transmission power of signalri, lambert's exponent number m=-ln2/ln (cos Ψ1/2), the half-power for transmission signal LED
Angle Ψ1/2, for reception signal photodetector physical area A, DiFor the distance between receiver and i-th emitter,
θiFor i-th LED angle of departure,Incidence angle for i-th of receiver relative to its normal direction,For i-th of LED light
The propagation coefficient of wave filter,It is the gain of i-th of LED light concentrator, size is determined by the following formula of formula：
Wherein, ΦcFor half angle at light concentrator visual angle, n is the refractive index of light concentrator.
Then r is calculated according to following formulai：
In formula, h is the vertical range of emitter and receiver.
Then the coordinate of receiver in a horizontal plane is calculated：
Q=(MTM)-1MTN,
Wherein,And Q is required receiver coordinate, Xi、
YiFor the abscissa and ordinate of the horizontal plane of i-th of emitter, riFor the horizontal range between receiver and i-th of emitter,
I=1,2 ..., n, n be emitter number.
In above-mentioned Di 2Calculation formula in, Ψ1/2、m、Φc、Ts, n, A be systematic parameter, it typically by artificially setting in advance
Surely obtain, and cos (θi)、Understand the recipient according to the direction of the launch of the transmitter of emitter and the receiver of receiver
To it is different and different.
In the present embodiment, the reception direction of the receiver of the direction of the launch of the transmitter of emitter and receiver all with day
Card is vertical, now has：
Because the height h of receiver is fixed, the simplification formula that can obtain the distance between transceiver is：
It can be obtained by above formula (3)：
Wherein, C is that systematic parameter in following table is calculated to the constant obtained by appropriate section in formula (2), and wherein C is specific
Calculating formula is as follows：
In the present embodiment, the size of partial parameters is as shown in the table.
Embodiments of the invention are described above in conjunction with accompanying drawing, but the invention is not limited in above-mentioned specific
Embodiment, above-mentioned embodiment is only schematical, rather than restricted, one of ordinary skill in the art
Under the enlightenment of the present invention, in the case of present inventive concept and scope of the claimed protection is not departed from, it can also make a lot
Form, these are belonged within the protection of the present invention.
Claims (10)
1. a kind of LED localization methods based on mixing OFDM, it is characterised in that include following step：
S1, multiple LED transmitters respectively send respective ACO-OFDM signals respectively afterwards together with PAM-DMT Signal averagings
Go out；
Wherein, ACO-OFDM signals are obtained by following methods：By input signal by M members quadrature amplitude modulation in strange carrier wave
On, complex data that generation length is N/4, even carrier wave whole zero setting, first and the N/2 subcarrier also zero setting, then change
Obtained after carrying out clipping operation for string code, wherein, M is the size of planisphere, and N is sub-carrier number；
PAM-DMT signals are obtained by following methods：Input signal is modulated at by even load using M members pulse amplitude modulating method
In the imaginary part of ripple, strange carrier wave whole zero setting, it is then converted into obtaining after string code carries out clipping operation；
Input signal includes coordinate of the emitter in horizontal plane；
S2, receiver estimate PAM-DMT signals respectively according to the signal of each emitter received, and according to estimating respectively
The PAM-DMT signals gone out reconstruct PAM-DMT signals respectively；
S3, receiver calculate receiver in water according to the PAM-DMT signals reconstructed of each emitter and corresponding coordinate
Coordinate in plane.
2. LED localization methods according to claim 1, it is characterised in that in the step S2, the PAM- of each emitter
The evaluation method of dmt signal includes following step：
S21, the signal received to receiver obtain the anti-ACO-OFDM computings of odd sequence progress after carrying out Fourier transformation, obtain
The ACO-OFDM signals of estimation；
S22, according to estimation ACO-OFDM signals, the clipped noise on even carrier wave is calculated；
S23, calculate and carry out obtaining even sequence after Fourier transformation by signal that receiver receives making an uproar with the amplitude limit on even carrier wave
The difference of sound, take estimated value of the imaginary part of difference as PAM-DMT signals.
3. LED localization methods according to claim 1, it is characterised in that in step S3, the seat of receiver in a horizontal plane
Mark is calculated by following formula：
Q=(MTM)-1MTN,
Wherein,And Q is required receiver coordinate, Xi、YiFor
The abscissa and ordinate of the horizontal plane of i-th of emitter, riFor the horizontal range between receiver and i-th of emitter, i=
1st, 2 ..., n, n are the number of emitter, riIt is calculated by following formula：
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<mo>,</mo>
</mrow>
In formula, PtAveraged for the power of PAM-DMT signals after i-th of LED reconstruct, PriFor i-th of LED PAM-
The average value of the transmission power of dmt signal, lambert's exponent number are m=-ln2/ln (cos Ψ1/2), Ψ1/2It is for transmission signal
LED half-power angle, A are the physical areas of the photodetector for reception signal, DiFor receiver and i-th emitter it
Between distance, θiFor i-th lamp angle of departure,Incidence angle for i-th of receiver relative to its normal direction,For i-th
The propagation coefficient of individual LED optical filter, hiFor vertical range of i-th of receiver between emitter,It is i-th
The gain of LED light concentrator, size are determined by the following formula of formula：
Wherein, ΦcFor half angle at light concentrator visual angle, n is the refractive index of light concentrator.
4. LED localization methods according to claim 1, it is characterised in that the signal direction of the launch and receiver of emitter
Receiving side signal to being calculated in perpendicular to ground, the coordinate of receiver in a horizontal plane by following formula：
Q=(MTM)-1MTN,
Wherein,And Q is required receiver coordinate, Xi、YiFor
The abscissa and ordinate of the horizontal plane of i emitter, riFor the horizontal range between receiver and i-th of emitter, i=1,
2nd ..., n, n be emitter number, riIt is calculated by following formula：
<mrow>
<msub>
<mi>r</mi>
<mi>i</mi>
</msub>
<mo>=</mo>
<msqrt>
<mrow>
<msup>
<mrow>
<mo>(</mo>
<mfrac>
<mrow>
<mi>C</mi>
<mo>&CenterDot;</mo>
<msub>
<mi>h</mi>
<mi>i</mi>
</msub>
<mo>&CenterDot;</mo>
<msub>
<mi>P</mi>
<mi>t</mi>
</msub>
</mrow>
<msub>
<mi>P</mi>
<mrow>
<mi>r</mi>
<mi>i</mi>
</mrow>
</msub>
</mfrac>
<mo>)</mo>
</mrow>
<mrow>
<mn>1</mn>
<mo>/</mo>
<mn>2</mn>
</mrow>
</msup>
<mo>-</mo>
<msup>
<msub>
<mi>h</mi>
<mi>i</mi>
</msub>
<mn>2</mn>
</msup>
</mrow>
</msqrt>
<mo>,</mo>
<mrow>
<mo>(</mo>
<mi>i</mi>
<mo>=</mo>
<mn>1</mn>
<mo>,</mo>
<mn>2</mn>
<mo>,</mo>
<mn>3</mn>
<mo>,</mo>
<mn>4</mn>
<mo>)</mo>
</mrow>
<mo>,</mo>
</mrow>
Wherein, C is preset constant, and its size meets
In formula, PtAveraged for the power of PAM-DMT signals after i-th of LED reconstruct, PriFor i-th of LED PAM-
The average value of the transmission power of dmt signal, lambert's exponent number are m=-ln2/ln (cos Ψ1/2), Ψ1/2It is for transmission signal
LED half-power angle, A are the physical areas of the photodetector for reception signal, DiFor receiver and i-th emitter it
Between distance, θiFor i-th lamp angle of departure,Incidence angle for i-th of receiver relative to its normal direction,For i-th
The propagation coefficient of individual LED optical filter, hiFor vertical range of i-th of receiver between emitter,It is i-th
The gain of LED light concentrator, size are determined by the following formula of formula：
Wherein, ΦcFor half angle at light concentrator visual angle, n is the refractive index of light concentrator.
5. LED localization methods according to claim 1, it is characterised in that the input signal also includes the transmitting fuselage
Part identification information, to enable the receiver for receiving the identity identification information to distinguish the coordinate of each emitter
Come.
6. a kind of LED alignment systems based on mixing OFDM, it is characterised in that include：
Multiple control modules, it is located at is loaded on multiple emitters respectively, for controls the multiple emitter respectively will be each respectively
From ACO-OFDM signals sent respectively afterwards together with PAM-DMT Signal averagings；
Wherein, ACO-OFDM signals are obtained by the first transmitter unit, the first transmitter unit be used for by input signal by M members just
Intermodulation width is modulated on strange carrier wave, generation length be N/4 complex data, even carrier wave whole zero setting, first and the N/2 son load
Ripple also zero setting, it is then converted into obtaining after string code carries out clipping operation, wherein, M is the size of planisphere, and N is sub-carrier number；
PAM-DMT signals are obtained by the second transmitter unit, and the second transmitter unit is used for will using M members pulse amplitude modulating method
Input signal is modulated in the imaginary part of even carrier wave, strange carrier wave whole zero setting, is then converted into obtaining after string code carries out clipping operation；
Input signal includes coordinate of the emitter in horizontal plane；
Signal reconstruction module, on receiver, for estimating PAM- respectively according to the signal of each emitter received
Dmt signal, and PAM-DMT signals are reconstructed according to the PAM-DMT signals estimated respectively respectively；
Position computation module, on receiver, for reconstructing PAM-DMT signals and corresponding seat according to each emitter
Mark calculates receiver coordinate in a horizontal plane.
7. LED alignment systems according to claim 6, it is characterised in that signal reconstruction module is estimated using following units
Calculate the PAM-DMT signals of each emitter：
ACO-OFDM signal estimation units, carry out obtaining odd sequence after Fourier transformation for the signal that receives receiver entering
The anti-ACO-OFDM computings of row, the ACO-OFDM signals estimated；
Even carrier wave clipped noise computing unit, for according to estimation ACO-OFDM signals, the amplitude limit being calculated on even carrier wave to be made an uproar
Sound；
PAM-DMT signal estimation units, even-order is obtained after the signal that receiver receives is carried out into Fourier transformation for calculating
The difference of row and the clipped noise on even carrier wave, takes estimated value of the imaginary part of difference as PAM-DMT signals.
8. LED alignment systems according to claim 6, it is characterised in that in position computation module, receiver is in horizontal plane
In coordinate be calculated by following formula：
Q=(MTM)-1MTN,
Wherein,And Q is required receiver coordinate, Xi、YiFor
The abscissa and ordinate of the horizontal plane of i-th of emitter, riFor the horizontal range between receiver and i-th of emitter, i=
1st, 2 ..., n, n are the number of emitter, riIt is calculated by following formula：
<mrow>
<msub>
<mi>r</mi>
<mi>i</mi>
</msub>
<mo>=</mo>
<msqrt>
<mrow>
<msubsup>
<mi>D</mi>
<mi>i</mi>
<mn>2</mn>
</msubsup>
<mo>-</mo>
<msup>
<msub>
<mi>h</mi>
<mi>i</mi>
</msub>
<mn>2</mn>
</msup>
</mrow>
</msqrt>
<mo>,</mo>
</mrow>
In formula, PtAveraged for the power of PAM-DMT signals after i-th of LED reconstruct, PriFor i-th of LED PAM-
The average value of the transmission power of dmt signal, lambert's exponent number are m=-ln2/ln (cos Ψ1/2), Ψ1/2It is for transmission signal
LED half-power angle, A are the physical areas of the photodetector for reception signal, DiFor receiver and i-th emitter it
Between distance, θiFor i-th lamp angle of departure,Incidence angle for i-th of receiver relative to its normal direction,For i-th
The propagation coefficient of individual LED optical filter,It is the gain of i-th of LED light concentrator, size is true by the following formula of formula
It is fixed：
Wherein, ΦcFor half angle at light concentrator visual angle, n is the refractive index of light concentrator.
9. LED alignment systems according to claim 6, it is characterised in that the signal direction of the launch and receiver of emitter
Receiving side signal to being calculated in perpendicular to ground, the coordinate of receiver in a horizontal plane by following formula：
Q=(MTM)-1MTN,
Wherein,And Q is required receiver coordinate, Xi、YiFor
The abscissa and ordinate of the horizontal plane of i emitter, riFor the horizontal range between receiver and i-th of emitter, i=1,
2nd ..., n, n be emitter number, riIt is calculated by following formula：
<mrow>
<msub>
<mi>r</mi>
<mi>i</mi>
</msub>
<mo>=</mo>
<msqrt>
<mrow>
<msup>
<mrow>
<mo>(</mo>
<mfrac>
<mrow>
<mi>C</mi>
<mo>&CenterDot;</mo>
<msub>
<mi>h</mi>
<mi>i</mi>
</msub>
<mo>&CenterDot;</mo>
<msub>
<mi>P</mi>
<mi>t</mi>
</msub>
</mrow>
<msub>
<mi>P</mi>
<mrow>
<mi>r</mi>
<mi>i</mi>
</mrow>
</msub>
</mfrac>
<mo>)</mo>
</mrow>
<mrow>
<mn>1</mn>
<mo>/</mo>
<mn>2</mn>
</mrow>
</msup>
<mo>-</mo>
<msup>
<msub>
<mi>h</mi>
<mi>i</mi>
</msub>
<mn>2</mn>
</msup>
</mrow>
</msqrt>
<mo>,</mo>
<mrow>
<mo>(</mo>
<mi>i</mi>
<mo>=</mo>
<mn>1</mn>
<mo>,</mo>
<mn>2</mn>
<mo>,</mo>
<mn>3</mn>
<mo>,</mo>
<mn>4</mn>
<mo>)</mo>
</mrow>
<mo>,</mo>
</mrow>
Wherein, C is preset constant, and its size meets
In formula, PtAveraged for the power of PAM-DMT signals after i-th of LED reconstruct, PriFor i-th of LED PAM-
The average value of the transmission power of dmt signal, lambert's exponent number are m=-ln2/ln (cos Ψ1/2), Ψ1/2It is for transmission signal
LED half-power angle, A are the physical areas of the photodetector for reception signal, DiFor receiver and i-th emitter it
Between distance, θiFor i-th lamp angle of departure,Incidence angle for i-th of receiver relative to its normal direction,For i-th
The propagation coefficient of individual LED optical filter, hiFor vertical range of i-th of receiver between emitter,It is i-th
The gain of LED light concentrator, size are determined by the following formula of formula：
Wherein, ΦcFor half angle at light concentrator visual angle, n is the refractive index of light concentrator.
10. LED alignment systems according to claim 6, it is characterised in that the input signal also includes the transmitting fuselage
Part identification information, to enable the receiver for receiving the identity identification information to distinguish the coordinate of each emitter
Come.
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| CN113422646A (en) * | 2021-05-31 | 2021-09-21 | 东北师范大学 | Zero value regression algorithm and device of HACO-OFDM modulation system |
| CN114124218A (en) * | 2021-11-22 | 2022-03-01 | 华南理工大学 | Geomagnetic sensor-assisted visible light single lamp positioning method and system |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109324311A (en) * | 2018-09-29 | 2019-02-12 | 中山大学 | A kind of bimodulus LED localization method and system based on different Lambertian radiation lobe moduluses |
| CN109324311B (en) * | 2018-09-29 | 2022-08-19 | 中山大学 | Dual-mode LED positioning method and system based on different Lambertian radiation lobe moduli |
| CN111711593A (en) * | 2020-06-22 | 2020-09-25 | 西安电子科技大学 | OFDM/OQAM-based modulation method for visible light communication system |
| EP4050362A1 (en) * | 2021-02-25 | 2022-08-31 | J.D. Geck GmbH | Method for determining the position of a mobile receiver within a building or a fixed device |
| CN113422646A (en) * | 2021-05-31 | 2021-09-21 | 东北师范大学 | Zero value regression algorithm and device of HACO-OFDM modulation system |
| CN114124218A (en) * | 2021-11-22 | 2022-03-01 | 华南理工大学 | Geomagnetic sensor-assisted visible light single lamp positioning method and system |
| CN114124218B (en) * | 2021-11-22 | 2023-02-28 | 华南理工大学 | Geomagnetic sensor-assisted visible light single lamp positioning method and system |
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