CN103346835A - High-speed visible light multiple-input multiple-output system and communication method thereof - Google Patents

Abstract

Provided is a high-speed visible light multiple-input multiple-output system and communication method of the high-speed visible light multiple-input multiple-output system. The high-speed visible light multiple-input multiple-output system comprises transmitting equipment and receiving equipment. The transmitting equipment comprises a control module, N drive circuits and N LED lamps, wherein the N driving circuits are connected with the signal output end of the control module, and the N LED lamps are connected with the signal output ends of the N drive circuits. The receiving equipment comprises a photovoltaic conversion module, an operational amplifier, an A/D conversion module and a signal recovery module, wherein the photovoltaic conversion module, the operational amplifier, the A/D conversion module and the signal recovery module are connected in series in sequence. The high-speed visible light multiple-input multiple-output system is simple in structure, high in speed and high in stability, can be further carried on multiple movable terminals in an integrated mode through an existing technology, and has strong adaptability.

Description

High speed visible light mimo systems and communication means thereof

Technical field

The invention belongs to the free space optical communication field, be between a kind of indoor visible light transmitting apparatus of integrated realization and the terminal equipment at a high speed, the solution of multichannel communication, a kind of high speed visible light mimo systems and communication means thereof specifically.

Background technology

At present, the visible light communication technology is that the high speed light and shade flash signal that is invisible to the naked eye of utilizing fluorescent lamp or light-emitting diode etc. to send is transmitted information, and the wire device of high-speed Internet is connected on the lighting device, inserts attaching plug and can use.The system that utilizes this technology to make can cover the scope that indoor light reaches, and computer does not need electric wire to connect, thereby has prospect widely.

Compare with the WLAN (wireless local area network) (WLAN) of present use, " visible light communication " system can utilize room lighting equipment instead of wireless LAN lan base station to transmit, and its communication speed can reach per second tens of million to hundreds of million.Utilize computer and personal digital assistant device special-purpose, can the receiving and transmitting signal function, as long as in the place that indoor light shines, just can download and upload data for a long time.Contrast is usually based on electromagnetic wireless transmission, and this system also has safe characteristics.Cover light with curtain, information just can not leak to outdoor, and indoor Information Security height can be applied to military affairs or other require the communication mode of strong security.Use multiple computers also can not influence communication speed simultaneously.Owing to do not use airwave communication, can freely use this system to the departments such as hospital of electromagnetic signal sensitivity.

Multiple-input, multiple-output (MIMO, Multiple Input-Multiple Output) refers to the transmission system that transmitting terminal and receiving terminal at communication link all use a plurality of transmission units, it can become the multipath factor that exists in the legacy communications system factor favourable to the telex network performance, thereby improves service transmission rate exponentially.Mimo systems is used widely in radio frequency (radio frequency) field, and Multiple Input Multiple Output has great importance to improving frequency spectrum resource utilization rate.Be example with wireless local local area network (LAN) (WLAN), 802.11 (n) standard of more recent application has adopted 4 reception antennas with the increase capacity at each receiving terminal.

The visible light mimo systems has some essential characteristics of MIMO communication system.For example adopt a plurality of transmitting terminals and a plurality of receiving terminal, can with channel correlation matrix describe between each transmitter and receiver bonding strength, can analyze inter-channel crosstalk from channel correlation matrix.Utilize the inverse matrix of channel correlation matrix multiply by to receive signal strength signal intensity and namely recover the transmission signal.

Visible light communication and visible light mimo systems development in recent years are rapid, following key technology and system imagination occurred, and they have proved visible light communication and mimo systems feasibility thereof from different perspectives.

In paper " Multi-Input Multi-Output (MIMO) indoor optical wireless communications ", the author is applied to the visible light mimo systems with the H matrix-analysis method.

Patent 200710047554.7 " visible light space division multiple access " has proposed to utilize the lens imaging method to separate the method that receive channel is realized multiple access communication.The optical imagery method that proposes in the patent need receive by CCD, and the CCD performance limitations to the communication speed influence greatly can't reach practical high-speed communication.Simultaneously, the optical lens imaging need be considered parameters such as focal length, and the ideal image surely that differs does not solve the cross-interference issue that imaging produces.This patent is compared with it, adopts digital space division multiplexing technology, avoids the uncertain factor of optical imagery, has improved processing speed and processing accuracy greatly.Also can be combined with its optics space division multiplexing technology simultaneously, obviously improve its later stage processing speed, strengthen link stability.

Patent: 200980150016.8 " visible light communication system and methods " have proposed a kind of multiplex communication of utilizing the three-color LED wavelength division multiplexing.The optical communication wavelength-division multiplex technique is another emphasis of visible light multichannel communication, but because its multi-wavelength to the influence of user's comfortableness and be not suitable for indoor communications, also needs the communication technology of the suitable specific wavelength of further research.Propose in the patent to describe inter-channel crosstalk and be used for restoring signal significant with channel matrix.

With respect to the wireless electromagnetic wave communication, visible light has good confidentiality, directionality height, theoretical velocity height, channel capacity is enriched, and is the important implementation of high speed short-range communication of future generation.This patent proposes a kind of practicality high speed visible light multiple-in and multiple-out communication method.

Summary of the invention

The present invention utilizes digital space division multiplexing technology to realize high speed visible light communication mimo communication.The space division multiplexing core technology is to eliminate a plurality of inter-channel crosstalk to reach the purpose of segregated channel.For this reason, we introduce matrix-analysis method.We are with the channel relevancy matrix description, and transmitting terminal is surveyed current channel relevant parameter by receiving terminal, separate multiplex (MUX) by the inverse matrix computing, set up communication link.For the system that makes can (being that channel parameter changes) keep communication link unimpeded in motion process, in the valid data transmission course, we design a kind of method that dynamically updates, and extract the channel relevant parameter from the communication link valid data.

Technical scheme of the present invention is:

A kind of high speed visible light mimo systems, it comprises transmitting apparatus and receiving equipment, described transmitting apparatus comprises control module, N the drive circuit that links to each other with the control module signal output part and N the LED lamp that is connected with N drive circuit signal output part respectively, described receiving equipment comprises photoelectric conversion module, the operational amplifier of serial connection successively, A/D modular converter and signal recover module;

In the transmitting apparatus,

Control module is used for realizing that the NRZ-OOK to the LED lamp modulates, produce the control signal of N LED lamp light on and off in fixing flicker at interval, control module is at first controlled LED and is sent lead code, back control sends valid data, described lead code comprises the channel parameter synchronous code, each LED lamp that sends valid data is that transmitting channel all exists a channel parameter corresponding synchronous code, aforementioned lead code and valid data are binary code, 0 or 1 of this binary code is that the TTL control signal is corresponding with the light on and off in fixing flicker at interval of LED lamp respectively;

Drive circuit is used for the TTL control signal of control module output is converted to the input current of LED lamp, the flicker of control LED lamp;

The LED lamp is used for sending the light of light on and off in the fixing flicker at interval;

In the receiving equipment,

Photoelectric conversion module be used for to receive the light signal of each LED lamp, and is converted into current signal and is sent to operational amplifier;

Operational amplifier is used for the current signal of photoelectric conversion module output is converted to stable voltage signal;

The A/D modular converter is used for the analog voltage signal of operational amplifier output is converted to digital voltage signal, and is sent to signal recover module;

Signal recover module receives the signal that the A/D modular converter is gathered, and obtains current channel parameter according to lead code, and recovers the valid data of transmitting terminal emission with this.

Lead code of the present invention comprises clock synchronous code, beginning flag sign indicating number and channel parameter synchronous code, and the clock synchronous code sends same signal for all channels with same frequency, is used for synchronous receiving terminal and transmitting terminal clock;

The channel parameter synchronous code is orthogonal sequence, and receiving terminal is estimated current channel parameter by the channel parameter synchronous code;

Each emission channel clock synchronous code has same form, and each emission channel channel parameter synchronous code is orthogonal.

Channel parameter synchronous code of the present invention is the E matrix of the capable N row of N, and each row is that transmitting channel exists one-to-one relationship with the LED lamp that sends valid data.

Signal of the present invention is handled recovery unit and is comprised clock recovery module CDR, recovery unit control module, channel parameter matrix H module, matrix operation module; Described clock recovery module CDR all links to each other with the digital voltage signal output of A/D modular converter output with the recovery unit control module, the signal output part of clock recovery module CDR and recovery unit control module all links to each other with the signal input part of channel parameter matrix H module, another signal output part of described recovery unit control module links to each other with the signal input part of matrix operation module, described matrix operation module and two-way connection of channel parameter matrix H module; Wherein,

Clock recovery module is in clock synchronous phase recovered clock from receiving data stream;

The recovery unit control module, clock is synchronous, channel parameter synchronous and valid data recover three kinds of states for switching;

Channel parameter matrix H module is obtained channel parameter matrix H and is inverted by receiving data, is used for recovering useful signal;

The matrix operation module is made up of the isostructural multiply accumulating structure in N road, carries out computing by the valid data Rx of channel parameter matrix H and receiver collection, recovers signal Tx _R=H ^-1* Rx.

Clock recovery module of the present invention comprises binaryzation decision device and clock synchronizer: the binaryzation decision device, and at the clock synchronous phase, will receive signal decision is 1/0 single-bit signal; Clock synchronizer, at the clock synchronous phase, recovered clock signal from binaryzation decision device result.

A kind of communication means of high speed visible light mimo systems, it may further comprise the steps:

At transmitting terminal,

Produce the multiplex (MUX) control signal, the control led drive circuit makes LED produce light on and off;

Multiplex (MUX) synchronized transmission clock synchronous code at first;

The second step multiplex (MUX) clock track sends the beginning flag sign indicating number;

The 3rd step multiplex (MUX) transmitting channel parameter synchronization sign indicating number;

The efficiently transmitting data emission state is gone in the 4th stepping, and multiplex (MUX) independently sends outer input data;

At receiving terminal,

The signal of telecommunication after signal recover module collection process opto-electronic conversion and the amplification is analyzed recovery;

Be in the clock recovery state after the initialization, clock recovery module extracts clock after with the input signal binaryzation;

The recovery unit control module enters the channel parameter synchronous regime after receiving beginning flag;

When the channel parameter synchronous regime: the recovery unit control module will receive the signal channel parameter and send channel parameter matrix H module to, and channel parameter matrix H module is inverted channel parameter and obtained H ^-1, enter valid data after finishing and return to form;

Return to form at valid data: the matrix operation module is with H ^-1Matrix and current reception signal Rx carry out computing, and judgement recovers signal Tx _R=H ^-1* Rx, wherein, H ^-1The inverse matrix of expression H, Rx represents the valid data signal that receiver is gathered, Tx _RThe signal that expression recovers;

Dynamically update channel parameter matrix H: the signal Tx that the recovery unit control module recovers according to valid data _RWith the valid data signal Rx that gathers, upgrading channel parameter matrix automatically is H ', realizes constantly that in transmission course channel parameter upgrades automatically, and the data that remain valid are recovered, and can keep link unimpeded in the relative motion process.

Among the present invention, when valid data returned to form, the recovery unit control module dynamically updated channel parameter matrix H in the recovery module, and its process is:

The signal Tx that the valid data signal Rx of recovery unit control module collection input and valid data recover _R

The signal Tx that the recovery unit control module selects valid data to recover ^RIn uncorrelated signal form the array T ' of full rank _R, and the valid data of correspondence are gathered signal form array R ';

Will (T ' _R) ^-1* R '=H ' obtains current up-to-date channel parameter matrix H ', finishes dynamically updating of channel parameter matrix.

Beneficial effect of the present invention:

System configuration of the present invention is simple, speed is fast, stability is high, by prior art can further integrated lift-launch on all multi-mobile-terminals, have very strong applicability.

The present invention utilizes digital space division multiplexing technology to realize high speed visible light communication mimo communication.The space division multiplexing core technology is to eliminate the purpose that a plurality of inter-channel crosstalk reach segregated channel.For this reason, we introduce matrix-analysis method.We separate multiplex (MUX) with the channel relevancy matrix description by algorithm, set up communication link.For the system that makes can (being that channel parameter changes) keep communication link unimpeded in motion process, in the valid data transmission course, we design a kind of algorithm that dynamically updates, and extract the channel relevant parameter from the communication link valid data.Realize constantly that in transmission course channel parameter upgrades automatically, the data that remain valid are recovered, and can keep link unimpeded in the relative motion process.

Description of drawings

Fig. 1 is the implication that matrix-analysis method is described channel relevancy, because different transmitting terminals there are differences to distance, the angle of departure of different receiving terminals, the light intensity that single receiving terminal receives is that each transmitting terminal transmits through the stack of the difference signal of different paths generation.

Fig. 2 is the case that high speed visible light mimo systems is applied to indoor visible light communication, and mobile phone is realized communicating by letter by the data that integrated detector receives and processing light sends with dull and stereotyped.

Fig. 3 is the communication means of realizing reaching synchronously automatically transfer of data, comprises packet structure and detailed annotation.

Fig. 4 is sending part subsystem block diagram.

Fig. 5 is the receiving unit system block diagram.

Fig. 6 is the block diagram that core is recovered module in the receiving unit.

Fig. 7 recovers the block diagram of matrix multiply accumulating computing module in the module.

Fig. 8 be dynamically update channel parameter (H matrix) method flow chart.

Embodiment

The present invention is further illustrated below in conjunction with drawings and Examples.

In order to set up the relation between light source and the detector, we introduce H matrix (channel correlation matrix) and characterize relation between each light source and the detector.Element h in the matrix _IjBe the DC current gain of each channel, i j signal strength signal intensity that light source sends that detector detects just.Element h in the H matrix _IjIn comprise many information, comprise the distance between light source and the detector, angle, light intensity etc. is used for restoring signal.The meaning of H matrix is shown in (Fig. 1).

Process of transmitting is as follows:

Going into n with n, to go out system be example, and H represents that channel parameter Tx represents to transmit, and Rx represents that receiver gathers signal strength signal intensity.

$\begin{array}{ccccc}\left[\begin{array}{ccccc}{h}_{11}& h_{12}& h_{13}& ...& h_{1n}\\ h_{21}& h_{22}& h_{23}& ...& h_{2n}\\ h_{31}& h_{32}& h_{33}& ...& h_{3n}\\ .& .& .& & .\\ .& .& .& & .\\ .& .& .& & .\\ h_{n1}& h_{n2}& {\mathrm{<figure-callout\; id="3"\; label="h\; n"\; filenames="HDA00003492286700022.png"\; state="\{\{state\}\}">h</figure-callout>}}_n& ...& h_{\mathrm{nn}}\end{array}\right]& *& \left[\begin{array}{c}{x}_1\\ x_2\\ x_3\\ .\\ .\\ .\\ x_n\end{array}\right]& =& \left[\begin{array}{c}{y}_1\\ y_2\\ {\mathrm{<figure-callout\; id="3"\; label="y"\; filenames="HDA00003492286700022.png"\; state="\{\{state\}\}">y</figure-callout>}}_3\\ .\\ .\\ .\\ y_n\end{array}\right]\\ H& *& \mathrm{Tx}& =& \mathrm{Rx}\end{array}$

The recovery process process is as follows:

Going into n with n, to go out system be example, H ^-1The inverse matrix of expression H, Rx represents receiver collection signal, Tx _RThe signal that (Tx Recovered) expression recovers.

$\begin{array}{ccccc}\left[\begin{array}{c}{x}_{1R}\\ x_{2R}\\ x_{3R}\\ .\\ .\\ .\\ x_{\mathrm{nR}}\end{array}\right]& =& {\left[\begin{array}{ccccc}{h}_{11}& h_{12}& h_{13}& ...& h_{1n}\\ h_{21}& h_{22}& h_{23}& ...& h_{2n}\\ h_{31}& h_{32}& h_{33}& ...& h_{3n}\\ .& .& .& & .\\ .& .& .& & .\\ .& .& .& & .\\ h_{n1}& h_{n2}& {\mathrm{<figure-callout\; id="3"\; label="h\; n"\; filenames="HDA00003492286700022.png"\; state="\{\{state\}\}">h</figure-callout>}}_n& ...& h_{\mathrm{nn}}\end{array}\right]}^{-1}& *& \left[\begin{array}{c}{y}_1\\ y_2\\ {\mathrm{<figure-callout\; id="3"\; label="y"\; filenames="HDA00003492286700022.png"\; state="\{\{state\}\}">y</figure-callout>}}_3\\ .\\ .\\ .\\ y_n\end{array}\right]\\ {\mathrm{Tx}}_R& =& H^{-1}& *& \mathrm{Rx}\end{array}$

In order to realize the data communication of efficient stable, receiver must be gathered current channel parameter (being the H matrix) before valid data arrive.In order accurately to gather the H matrix, send the reception both sides and need adopt certain communication protocol to reach synchronous purpose.

In the real-time communication process, if changing of transmitter and receiver relative position will cause the change of channel parameter, namely the H matrix changes.The communication protocol of this patent design has solved link when channel parameter changes to a certain extent from the recovery problem, has inserted clock synchronous code and channel parameter synchronous code at the former frames of each packet.But in the face of the very complicated motion conditions of mobile communication, data link stability can reduce.In order to improve the data link stability in the motion state, this patent proposes a kind of method of extracting the H matrix from the communication valid data.(as Fig. 8)

Owing in the high-speed communication process, it is limited that the relative motion of transmitter and receiver decomposes each frame time interior (being the us level when communicating by letter to Mbps) variation, owing to adjudicate necessarily redundancy of existence, recovers module and still can correctly recover data.Utilize this point, we choose sequence and form non-singular matrix T ' in the data that recover recently _R, utilize the receiving matrix R ' of its corresponding sequence, calculate H ', i.e. current up-to-date channel correlation matrix.Like this, recovering module can constantly dynamically update the H matrix simultaneously at the recovery valid data, reaches to keep the unimpeded purpose of link in the motion process.

Hardware designs:

Send part and utilize current feedback type operational amplifier THS3091 driving LED array (LUXEONSTAR), input signal is modulated to visible light LED goes up emission.(as Fig. 4)

Receiving unit comprises photoelectric conversion module PIN pipe, high-performance low noise amplifier OPA637, high-speed a/d module (analog-digital conversion), signal recover module.(as Fig. 5)

Wherein signal processing recovery module comprises clock recovery module (CDR), control module, H matrix module, matrix operation module module.The recovered part of handling signal adopts IP (Intellectual Property core) to change design and realizes, can be transplanted to kinds of processes and make integrated circuit.Realize that with general processor (von Neumann structure or Harvard structure) compare, have the highly-parallel characteristic, can reach very high throughput speed, effectively reduce system power dissipation, be convenient to integrated.Module feasibility that we have adopted the FPGA platform validation.(as Fig. 6) specific implementation of the present invention is that a visible light 4 is gone into 4 and gone out communication system (Fig. 2).System has comprised a VISIBLE LIGHT EMISSION end (2-1) that can be connected with the Internet or other proprietary networks, and mobile receiving terminal (2-2/2-3).Transmitting terminal is modulated to network signal on the visible light LED (2-1-1), and receiving terminal obtains the light intensity signal of diverse location by electrooptical device (2-2-1), separates 4 channels by special algorithm, realizes 4 tunnel parallel communicationss.

Send part (Fig. 4) and form (4-2) by control module (4-1), visible light LED (4-3), drive circuit.Control module connects drive circuit, realizes the time program process of communication protocol (Fig. 3).Drive circuit is converted into the input current of LED with the TTL signal of control module, the flicker of control LED lamp.When control module is high level (with ' 1 ' expression), LED is bright; Be low level (with ' 0 ' expression) that LED goes out.

Receiving unit (Fig. 5) is made up of PIN photodiode (5-1), amplifier (5-2), high-speed a/d module (5-3) and recovery module (5-4).PIN photodiode (5-1) transfers the spatial light signal to current signal, handles through operational amplifier (5-2) to become stable voltage signal.High-speed a/d (5-3) is converted into analog voltage signal and recovers the digital voltage signal that module (5-4) can be handled.

Recover to comprise clock recovery module (6-1), control module (6-2), H matrix module (6-3), matrix operation module (6-4) in the module (5-4 and Fig. 6).Clock recovery module (6-1) is binary conversion treatment after initial phase will be gathered signal decision, therefrom extracts stabilizing clock.Control module (6-2) is extracted beginning flag from gather signal, the renewal of control H matrix module (6-3) and dynamically adjustment.H matrix module (6-3) is chosen the full rank sequence, finding the inverse matrix H from gather signal ^-1Pass to matrix operation module (6-4).

Matrix operation module (6-3 and Fig. 7) is made up of 4 multipliers (7-2) and 3 adders (7-3) and 1 decision device (7-4), finishes the multiply accumulating computing, corresponding H ^-1Certain delegation of matrix with gather signal multiplication (7-1), decision device is decision threshold with 0.5, if multiplication result (7-5) is greater than 0.5 decision device output 1 otherwise export 0 (7-6).Thus, recover one road signal thus.Recover 4 road signal demands, 4 tunnel isostructural matrix operation modules.

Case study on implementation:

The course of work is as follows, is that 4 transmitting channels are example with 4 LED lamps:

The first step:

Send 4 LED of part send packet with same frequency F clock synchronous code (10101010 ...).

The receiving unit clock synchronization module will extract stabilizing clock this moment from gather signal, as the later stage recovered clock of this packet.

Second step:

Send 4 LED of part and send beginning flag sign indicating number (ASCII ' SH ') simultaneously.

Control module is waited for the arrival of beginning flag in the receiving unit.

The 3rd step:

Send part transmitting channel parameter synchronization sign indicating number successively, sequence T ₁[1,0,0,0] ^T, T ₂[0,1,0,0] ^T, T ₃[0,0,1,0] ^T, T ₄[0,0,0,1] ^T, i.e. E matrix.

Receiving unit receives behind the beginning flag and gathers signal R in four cycles ₁, R ₂, R ₃, R ₄By formula Rx=H*Tx as can be known, R ₁, R ₂, R ₃, R ₄It is H that the 4*4 matrix R that forms is H*E.The H of control module control subsequently matrix module is obtained H ^-1, the H matrix module is with H ^-1Give 4 tunnel matrix operation modules in row and separately.

Experimental data

When sending part divides emission [1 00 0] ^T, receive R1 and be [36 16 35 63] ^T

When sending part divides emission [0 10 0] ^T, receive R2 and be [12 41 136 22] ^T

When sending part divides emission [0 01 0] ^T, receive R3 and be [29 155 27 17] ^T

When sending part divides emission [0 00 1] ^T, receive R4 and be [169 22 19 26] ^T

Be that the H matrix is

$\left[\begin{array}{cccc}36& 12& 29& 169\\ 16& 41& 155& 33\\ 35& 136& 27& 19\\ 63& 22& 17& 26\end{array}\right]$

Invert H ^-1

$\left[\begin{array}{cccc}-0.002399& -0.001193& -0.002491& 0.018931\\ -0.000082& -0.000936& 0.008354& -0.004350\\ -0.001142& 0.007017& -0.002013& -0.000011\\ 0.006630& -0.000882& 0.000283& -0.002722\end{array}\right]$

The 4th step:

Sending part separately starts and send valid data T ₅(the valid data are here imported by the outside, can be four tunnel signal sources independently, also can be that one tunnel signal source parallelization sends.Signal source can be the Internet or other dedicated networks)

Receiving unit collects data R ₅, by formula Rx=H ^*Tx is Tx=H as can be known ^-1* Rx.The output of matrix operation module is through matrix multiplication T _5R

Experimental data

Sending part divides the transmission data $T_5{\left[\begin{array}{cccc}1& 1& 0& 0\end{array}\right]}^T$

Receiving unit receives $R_5{\left[\begin{array}{cccc}46& 59& 168& 79\end{array}\right]}^T$

Receiving unit is through matrix operation Tx _R=H ^-1* Rx gets ${\left[\begin{array}{cccc}0.896& 0.999& 0.022& 0.006\end{array}\right]}^T,$ With 0.5 serve as the judgement after obtain $T_{5\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HDA00003492286700022.png,HDA00003492286700042.png"\; state="\{\{state\}\}">R</figure-callout>}}{\left[\begin{array}{cccc}1& 1& 0& 0\end{array}\right]}^T$ Finishing a secondary data recovers;

Step after the 5th step reached:

Transmission and receiving unit reruned for the 4th step,

Sending part divides transmission T ₆T ₇T ₈

Receiving unit image data R ₆R ₇R ₈, and recover data T _6RT _7RT _8R

The service of dynamically updating of H matrix brings into operation.

At a time, send part and receiving unit relative position generation slight change, namely channel H matrix is changed to H '.With former H ask H ^-1With the Rx of this moment carry out the matrix operation result do not reaccees desirable 0 and 1, but because judgement exists certain redundantly, recover module and still can correctly recover data.

This moment control module and H matrix module will from the data that recover, select sequence [T ' _1R, T ' _2R, T ' _3R, T ' _4R] composition 4*4 non-singular matrix T ' _R(selecting algorithm such as Fig. 8).Its corresponding image data is formed 4*4 matrix R '.Can be got by Rx=H*Tx, the H ' that current time is new=R ' * (T ' _R) ^-1H ' is up-to-date channel H matrix.

Experimental data

T’ _R：

$\left[\begin{array}{cccc}1& 1& 0& 1\\ 1& 0& 0& 0\\ 0& 0& 1& 0\\ 0& 0& 1& 1\end{array}\right]$

Corresponding R ':

$\left[\begin{array}{cccc}51& 31& 168& 158\\ 74& 15& 170& 38\\ 214& 34& 53& 46\\ 94& 63& 31& 81\end{array}\right]$

By H '=R ' ^*(T ' _R) ^-1Obtain up-to-date H ':

$\left[\begin{array}{cccc}31& 20& 41& 127\\ 15& 59& 147& 23\\ 34& 180& 41& 12\\ 63& 31& 13& 18\end{array}\right]$

Because communication link is with high speed operation, system can collect non-singular matrix T ' at the utmost point in the short time _RAnd upgrade channel H matrix.In actual use, if mobile receiving terminal (mobile phone, flat board etc.) position is moved, the channel relevant parameter can dynamically be adjusted at a high speed in the system, keeps communication link unobstructed.Such scheme is described native system detailed operation process.It is simple in structure, speed is fast, stability is high, by prior art can further integrated lift-launch on all multi-mobile-terminals, have very strong applicability.

The part that the present invention does not relate to all prior art that maybe can adopt same as the prior art is realized.

Claims (7)

1. high speed visible light mimo systems, it is characterized in that it comprises transmitting apparatus and receiving equipment, described transmitting apparatus comprises control module, N the drive circuit that links to each other with the control module signal output part and N the LED lamp that is connected with N drive circuit signal output part respectively, described receiving equipment comprises photoelectric conversion module, the operational amplifier of serial connection successively, A/D modular converter and signal recover module;

In the transmitting apparatus,

Control module is used for realizing that the NRZ-OOK to the LED lamp modulates, produce the control signal of N LED lamp light on and off in fixing flicker at interval, control module is at first controlled LED and is sent lead code, back control sends valid data, described lead code comprises the channel parameter synchronous code, each LED lamp that sends valid data is that transmitting channel all exists a channel parameter corresponding synchronous code, aforementioned lead code and valid data are binary code, and 0 or 1 of this binary code is that the TTL control signal is corresponding with the light on and off in fixing flicker at interval of LED lamp respectively;

Drive circuit is used for the TTL control signal of control module output is converted to the input current of LED lamp, the flicker of control LED lamp;

The LED lamp is used for sending the light of light on and off in the fixing flicker at interval;

In the receiving equipment,

Photoelectric conversion module be used for to receive the light signal of each LED lamp, and is converted into current signal and is sent to operational amplifier;

Operational amplifier is used for the current signal of photoelectric conversion module output is converted to stable voltage signal;

The A/D modular converter is used for the analog voltage signal of operational amplifier output is converted to digital voltage signal, and is sent to signal recover module;

Signal recover module receives the signal that the A/D modular converter is gathered, and obtains current channel parameter according to lead code, and recovers the valid data of transmitting terminal emission with this.

2. high speed visible light mimo systems according to claim 1, it is characterized in that described lead code comprises clock synchronous code, beginning flag sign indicating number and channel parameter synchronous code, the clock synchronous code sends same signal for all channels with same frequency, is used for synchronous receiving terminal and transmitting terminal clock;

The channel parameter synchronous code is orthogonal sequence, and receiving terminal is estimated current channel parameter by the channel parameter synchronous code;

Each emission channel clock synchronous code has same form, and each emission channel channel parameter synchronous code is orthogonal.

3. high speed visible light mimo systems according to claim 1 is characterized in that described channel parameter synchronous code is the E matrix of the capable N row of N, and each row is that transmitting channel exists one-to-one relationship with the LED lamp that sends valid data.

4. high speed visible light according to claim 1 multiple-input, multiple-output wherein is characterized in that described signal processing recovery unit comprises clock recovery module CDR, recovery unit control module, channel parameter matrix H module, matrix operation module; Described clock recovery module CDR all links to each other with the digital voltage signal output of A/D modular converter output with the recovery unit control module, the signal output part of clock recovery module CDR and recovery unit control module all links to each other with the signal input part of channel parameter matrix H module, another signal output part of described recovery unit control module links to each other with the signal input part of matrix operation module, described matrix operation module and two-way connection of channel parameter matrix H module; Wherein,

Clock recovery module is in clock synchronous phase recovered clock from receiving data stream;

The recovery unit control module, clock is synchronous, channel parameter synchronous and valid data recover three kinds of states for switching;

Channel parameter matrix H module is obtained channel parameter matrix H and is inverted by receiving data, is used for recovering useful signal;

The matrix operation module is made up of the isostructural multiply accumulating structure in N road, carries out computing by the valid data Rx of channel parameter matrix H and receiver collection, recovers signal Tx _R=H ^-1* Rx.

5. high speed visible light mimo systems according to claim 4 is characterized in that clock recovery module comprises binaryzation decision device and clock synchronizer: the binaryzation decision device, and at the clock synchronous phase, will receive signal decision is 1/0 single-bit signal; Clock synchronizer, at the clock synchronous phase, recovered clock signal from binaryzation decision device result.

6. the communication means of the described high speed visible light of one of claim 1-5 mimo systems is characterized in that it may further comprise the steps:

At transmitting terminal,

Produce the multiplex (MUX) control signal, the control led drive circuit makes LED produce light on and off;

Multiplex (MUX) synchronized transmission clock synchronous code at first;

The second step multiplex (MUX) clock track sends the beginning flag sign indicating number;

The 3rd step multiplex (MUX) transmitting channel parameter synchronization sign indicating number;

The efficiently transmitting data emission state is gone in the 4th stepping, and multiplex (MUX) independently sends outer input data;

At receiving terminal,

The signal of telecommunication after signal recover module collection process opto-electronic conversion and the amplification is analyzed recovery;

Be in the clock recovery state after the initialization, clock recovery module extracts clock after with the input signal binaryzation;

The recovery unit control module enters the channel parameter synchronous regime after receiving beginning flag;

When the channel parameter synchronous regime: the recovery unit control module will receive the signal channel parameter and send channel parameter matrix H module to, and channel parameter matrix H module is inverted channel parameter and obtained H ^-1, enter valid data after finishing and return to form;

Return to form at valid data: the matrix operation module is with H ^-1Matrix and current reception signal Rx carry out computing, and judgement recovers signal Tx _R=H ^-1* Rx, wherein, H ^-1The inverse matrix of expression H, Rx represents the valid data signal that receiver is gathered, Tx _RThe signal that expression recovers;

Dynamically update channel parameter matrix H: the signal Tx that the recovery unit control module recovers according to valid data _RWith the valid data signal Rx that gathers, upgrading channel parameter matrix automatically is H ', realizes constantly that in transmission course channel parameter upgrades automatically, and the data that remain valid are recovered, and can keep link unimpeded in the relative motion process.

7. the communication means of high speed visible light mimo systems according to claim 6 is characterized in that, when valid data returned to form, the recovery unit control module dynamically updated channel parameter matrix H in the recovery module, and its process is:

The signal Tx that the valid data signal Rx of recovery unit control module collection input and valid data recover _R

The signal Tx that the recovery unit control module selects valid data to recover _RIn uncorrelated signal form the array T ' of full rank _R, and the valid data of correspondence are gathered signal form array R ';

Will (T ' _R) ^-1* R '=H ' obtains current up-to-date channel parameter matrix H ', finishes dynamically updating of channel parameter matrix.

Images