CN112583486A - Visible light bidirectional high-speed communication system and communication method - Google Patents
Visible light bidirectional high-speed communication system and communication method Download PDFInfo
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- H04B10/114—Indoor or close-range type systems
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Abstract
The invention discloses a visible light bidirectional high-speed communication system, which comprises at least two communication terminals and an automatic control module for controlling the communication terminals to communicate, wherein each communication terminal comprises an information sending module and an information receiving module, the information sending module is used for receiving information transmitted by an upper computer and converting the information into optical signals, the information receiving module is used for receiving the optical signals and converting the optical signals into electric signals and then sending the electric signals to a lower computer, emitting light sources of the two communication terminals which are mutually communicated adopt array light sources with different wave bands, and a filter plate for avoiding self-interference is arranged on a photoelectric detection module; the invention adopts a time division multiplexing pulse modulation and demodulation method, makes full use of time slots, reduces the complexity requirements on a modulation pulse generating circuit and a light source driving circuit, and improves the communication rate; the receiving and transmitting integrated communication terminal realizes the functions of one-way and two-way communication, and the automatic control module is provided with an error detection and correction mechanism to ensure the reliability of information transmission.
Description
Technical Field
The invention relates to the technical field of underwater visible light communication, in particular to a visible light bidirectional high-speed communication system and a communication method.
Background
The visible light communication technology is a communication mode which takes visible light information as a carrier, modulates the visible light information by coding, and transmits the information through a channel. The technology has a series of advantages of electromagnetic interference resistance, good transmission confidentiality, energy conservation, rich spectrum resources and the like. Particularly, in the information and big data era today, efficient information acquisition means are urgently needed in the application fields of mobile communication, network systems, positioning systems, submarine communication, underwater sensing, ocean observation and the like, so that higher requirements are put forward on the communication speed of the visible light communication technology. The prior art mainly improves the visible light communication rate by changing a modulation and demodulation method, an OOK or PPM pulse modulation and demodulation method is mostly adopted in engineering application, from the perspective of realization of pulse modulation and demodulation design, the higher the pulse modulation rate is, the narrower the pulse is, the smaller the pulse duty ratio is, which generates high requirements on a generation circuit of modulation pulse and a light source driving circuit between modulation pulse and a light source, and simultaneously, the problems that the light source driving circuit stops working along with over-temperature protection, error codes are caused by insufficient response speed of the light source driving circuit, the continuous high-speed working life of the light source is shortened, the design cost is extremely high and the like are caused.
Disclosure of Invention
The technical purpose is as follows: the invention discloses a visible light bidirectional high-speed communication system and a communication method, which can realize bidirectional high-speed communication based on pulse modulation and prevent mutual interference between communication links, aiming at the defects that the existing visible light communication system can not realize quick information interactive transmission and has serious self-interference problem, low pulse modulation communication rate and the like.
The technical scheme is as follows: in order to achieve the technical purpose, the invention adopts the following technical scheme:
a visible light bidirectional high-speed communication system comprises at least two communication terminals and an automatic control module used for controlling communication between the communication terminals, wherein each communication terminal comprises an information sending module and an information receiving module, the information sending module is used for receiving information transmitted by an upper computer and converting the information into optical signals to be emitted, the information sending module comprises a coding module, a modulation module, a driving module and a transmitting light source which are connected in sequence, the information receiving module is used for receiving the optical signals and converting the optical signals into electric signals to be sent to a lower computer, and the information receiving module comprises a photoelectric detection module, a small signal amplification circuit, an automatic gain control circuit, a demodulation module and a decoding module which are connected in sequence;
the coding module is used for coding the information sent by the upper computer;
the modulation module is used for carrying out pulse modulation on the output signal of the coding module;
the driving module comprises a transmitting light source for converting signals into optical signals;
the transmitting light source is used for transmitting the converted optical signal to an information receiving module of another communication terminal;
the photoelectric detection module is used for receiving optical signals and converting the optical signals into electric signals;
the small signal amplifying circuit is used for enhancing the signal-to-noise ratio of the electric signal converted by the photoelectric detection module;
the demodulation module and the decoding module are used for demodulating and decoding the electric signals.
Preferably, the emission light source adopts the array light source, and every emission light source includes the independent signal light source of a plurality of, and drive module's quantity corresponds with signal light source quantity, 1 signal light source of every drive module drive, and photoelectric detection module adopts photoelectric detector, and photoelectric detector's receiving terminal sets up and is used for carrying out filterable filter to the light signal, and signal light source equipartition is around the filter.
Preferably, each of the signal light sources includes a plurality of sub-array light sources, and a lens for adjusting a divergence angle is disposed at a front end of the signal light source.
Preferably, a preamble module and a time division multiplexing module are arranged between the modulation module and the driving module, and a synchronization module is arranged between the automatic gain control circuit and the demodulation module;
the lead code module is used for adding a lead code of identification data to the data front end output by the modulation module;
the time division multiplexing module is used for carrying out time division multiplexing processing on the data output by the lead code module and transmitting the data to the driving module to be converted into optical signals to be transmitted out, the time division multiplexing module is provided with a control interface for controlling the signal transmission rate and power, and the time division multiplexing module comprises a coding counter for coding and counting the signals;
the synchronization module is used for identifying the lead code of the electric signal output by the photoelectric detection module and carrying out bit synchronization and frame synchronization.
Preferably, the communication terminal is divided into a communication terminal a and a communication terminal B, the emission light source of the communication terminal a is the emission light source a, and the photoelectric detection module of the communication terminal a is the photoelectric detection module a; the transmitting light source of the communication terminal B is a transmitting light source B, the photoelectric detection module of the communication terminal B is a photoelectric detection module B, and the transmitting light source A and the transmitting light source B adopt light sources with different wave bands.
Preferably, the receiving end of the photoelectric detection module a is provided with a filter a corresponding to the light source band of the emission light source a, and the receiving end of the photoelectric detection module B is provided with a filter B corresponding to the light source band of the emission light source B.
A communication method of a visible light bidirectional high-speed communication system comprises the following steps:
s01, firstly, the automatic control module controls the information sending module of the communication terminal A to continuously send a handshake request signal, after the communication terminal B receives the handshake request signal, the information sending module of the communication terminal B sends a handshake feedback signal, after the communication terminal A receives the handshake feedback signal, the communication terminal A stops sending the handshake request, and the communication terminal A and the communication terminal B establish a communication link;
and S02, after the communication link is established, the automatic control module controls the communication terminal A and the communication terminal B to send and receive information mutually, and unidirectional or bidirectional information transmission is carried out.
Preferably, in step S02, the communication terminal sending the information controls the corresponding signal light sources to emit light simultaneously through the driving module by the time division multiplexing module to perform transmission of the same signal.
Preferably, in step S02, the communication terminal sending the information performs time division multiplexing processing on the information to be transmitted through the time division multiplexing module, and the time division multiplexing module controls the corresponding signal light sources to sequentially emit light according to a predetermined non-overlapping time sequence through the driving module, and transmits the signal to another communication terminal.
Preferably, the time division multiplexing processing method includes the steps of:
1) recording the total number of the signal light sources as n, numbering the signal light sources of each group of emission light sources, and recording the signal light sources as n in sequence1、n2、n3……nn(ii) a Firstly, a lead code module adds a lead code M in front of pulse modulation information output by a modulation module to form serial data streams, each serial data stream comprises a plurality of modulation units t, each modulation unit is divided into a plurality of effective modulation units tau, the lead code M is used for identifying each group of signals needing to be transmitted, a time division multiplexing module carries out coding counting on the number of the effective modulation units tau in the serial data streams through a coding counter, the counting value N of the coding counter is less than or equal to the number N of signal light sources contained in each emission light source, wherein N represents the number of the effective modulation units tau needing to be transmitted in each modulation unit, and N is more than or equal to 1 and less than or equal to N;
2) the time division multiplexing module extracts the effective modulation unit tau with the code count of 11Will tau be1To n1The driving module corresponding to the signal light source extracts the effective modulation unit tau with the code count of 22Will tau be2To n2A driving module corresponding to the signal light source extracts the effective modulation unit tau with the code count of N by analogy in turnNWill tau beNTo nNThe driving module corresponding to the signal light source finally forms N groups of optical signals to be emitted;
3) the photoelectric detection module of the information receiving module receives N groups of optical signals and converts the optical signals into electric signals, after the electric signals are processed by the small signal amplification circuit and the automatic gain control circuit, the synchronization module identifies lead codes of the electric signals, pulse characteristics and lead code elements to realize bit synchronization, then the lead code elements are matched with code lengths to complete frame synchronization, and the electric signals are demodulated, decoded and sent to the automatic control module;
4) and the automatic control module detects whether the signal has a lost frame or an invalid frame, controls the communication terminal to send a lost frame retransmission request until the information is complete, and completes the information transmission.
Has the advantages that: the visible light bidirectional high-speed communication system and the communication method provided by the invention have the following beneficial effects:
1. the two communication terminals for bidirectional information transmission are only different in receiving and transmitting wave bands, and are matched for communication through the two communication terminals, so that unidirectional, semi-bidirectional and full-bidirectional communication is realized, the use is flexible, and the use range is wide.
2. The transmitting light sources of the communication terminal A and the communication terminal B adopt light sources with different wave bands, and the communication terminal is provided with the filter plate corresponding to the transmitting light source on the photoelectric detection module, the filter plate can filter the luminous wave band of the communication terminal, so that the self-luminous self-receiving self-interference problem can be effectively avoided, and the signal transmission is stable and reliable.
3. The transmitting light source of the communication terminal adopts an array light source, the transmitting light source comprises a plurality of signal light sources which are independently arranged, each signal light source is provided with a corresponding driving module, when the signal light sources synchronously transmit the same signal, the transmitting power is higher than that of a single signal light source, the communication at a longer distance can be supported, the transmitting power is adjusted by adjusting the number of the signal light sources, the condition that the receiving saturation is caused by overhigh optical power when the power is fixed by the light sources in short-distance communication is avoided, and the communication terminal is suitable for communication at different communication distances, namely, near, medium and far distances.
4. The signal light source is provided with the plurality of sub-array light sources, the transmitting power of each signal light source is adjustable, the power adjusting range of the signal light sources is further expanded, the problem that communication is influenced due to accidental damage of a certain sub-light source device can be effectively solved, and the adaptability of the communication terminal is improved.
5. The transmitting light source of the communication terminal supports the time division multiplexing technology, each signal light source in the transmitting light source is controlled to emit light without overlapping according to a set time sequence through the time division multiplexing module, different information is transmitted by fully utilizing time slots, the communication rate is improved in a multiple relation compared with the communication rate of a single light source, and the requirement of high-speed communication is met.
6. The time division multiplexing module is provided with a control interface for controlling and adjusting the communication rate and the transmitting power, and the dynamic adjustment of the communication rate and the dynamic adjustment of the transmitting power are realized through the control interface in the process of mutual movement of two communication terminals.
The invention adopts a pulse modulation and demodulation method, can greatly reduce the complexity requirements on a generation circuit of modulation pulse and a light source driving circuit, and can avoid the problems of error codes, reduction of the continuous high-speed working life of a light source and the like caused by over-temperature protection of the light source driving circuit and insufficient response speed of the light source driving circuit.
8. The lead code module is arranged behind the modulation module and in front of the time division multiplexing module, so that the occupation ratio of the lead code in effective communication information can be reduced, the influence on the communication rate is reduced to the greatest extent, and the purity of the communication rate is improved.
9. The communication terminal provided by the invention has the advantages that the lens is arranged at the front end of the signal light source, the divergence angle of the signal light source is adjusted by adjusting the distance between the lens and the signal light source, the coverage range of the light source is wide, the communication opening angle is wider, the adjustment range of the divergence angle of the light beam can reach 10-45 degrees, the communication is easier and quicker to establish, the communication link is stable, and the disconnection is difficult.
10. The invention controls the communication between the communication terminals through the automatic control module, is provided with an error correction and detection mechanism, detects whether a lost frame or an invalid frame exists in the information received by the communication terminals, controls the communication terminals to send a lost frame retransmission request if the lost frame or the invalid frame exists until the information is correct, can solve the problem of large-area error codes caused by frame loss and channel emergency caused by the communication link problem, makes up the defect of conventional coding, makes up the irreversible data loss in a one-way communication system, and greatly enhances the reliability of the system.
11. The communication terminals automatically establish communication, and the communication link between the two communication terminals is established by sending the handshake request, so that the communication method is suitable for information interaction among underwater unmanned aerial vehicles, between the underwater unmanned aerial vehicles and submerged beacons and in an atmospheric environment, and is also suitable for information interaction among underwater networking equipment.
12. The design scheme of the invention has the advantages that the upper automatic control module actively controls and the lower communication terminal passively transmits, can avoid the floating maintenance times of the underwater communication terminal during debugging, testing, problem troubleshooting and data transmission, only needs to modify the software of the automatic control module, and is simple and efficient to maintain for underwater operation.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.
FIG. 1 is a flow chart of the operation of the communication terminal of the present invention;
FIG. 2 is a flow chart of the operation of the message sending module of the present invention;
FIG. 3 is a flow chart of the operation of the message receiving module of the present invention;
FIG. 4 is a schematic diagram of a design of an emission light source and a filter of a communication terminal according to the present invention;
FIG. 5 is a flow chart for automatically establishing communications according to the present invention;
FIG. 6 is a schematic diagram of a time division multiplexing module of the present invention;
wherein, 1-signal light source and 2-filter.
Detailed Description
The present invention will be more clearly and completely described below by way of a preferred embodiment in conjunction with the accompanying drawings, without thereby limiting the scope of the invention to the described embodiment.
Fig. 1 shows a visible light bidirectional high-speed communication system provided by the present invention, which includes at least two communication terminals and an automatic control module for controlling communication between the communication terminals, each communication terminal includes an information sending module and an information receiving module; as shown in fig. 2, the information receiving module includes a coding module, a modulation module, a driving module and a transmitting light source, and a preamble module and a time division multiplexing module are sequentially arranged between the modulation module and the driving module; as shown in fig. 3, the information receiving module includes a photodetection module, a small signal amplifying circuit, an automatic gain control circuit, a demodulation module and a decoding module, which are connected in sequence, and a synchronization module is arranged between the automatic gain control circuit and the demodulation module.
The information sending module is connected with the upper computer and used for converting information of the upper computer into optical signals to be sent out, the coding module is used for coding the information sent by the upper computer, the modulation module is used for carrying out pulse modulation on output signals of the coding module, the lead code module adds lead codes of identification data to the front end of data output by the modulation module, and the time division multiplexing module receives the data output by the lead code module and converts the signals into the optical signals to be sent out through the driving module and the light emitting source in a time division multiplexing mode.
The information receiving module is connected with the lower computer and used for converting the received optical signals into electric signals, processing the electric signals and transmitting the electric signals to the lower computer, and displaying information on the lower computer; the photoelectric detection module is used for receiving optical signals and converting the optical signals into electric signals, the small signal amplification circuit amplifies the electric signals, the signal to noise ratio is enhanced, signals which are actually used for transmission are distinguished conveniently, gain processing is carried out on the enhanced signals through the automatic gain control circuit, the demodulation difficulty is reduced, the synchronization module identifies lead codes, the signals are integrated, bit synchronization and frame synchronization are achieved, finally, demodulation and decoding are carried out through the demodulation module and the decoding module to obtain transmitted information, the automatic control module detects whether lost frames or invalid frames exist in the signals or not, the communication terminal is controlled to send lost frame retransmission requests, and information transmission is completed until the information is complete.
The coding module, the modulation module, the demodulation module and the decoding module adopt FPGA or a singlechip.
The communication terminal is divided into a communication terminal A and a communication terminal B, an upper computer and a lower computer which are connected with the communication terminal A are respectively an upper computer A and a lower computer B, and an upper computer and a lower computer which are connected with the communication terminal B are respectively an upper computer B and a lower computer A; the transmitting light source of the communication terminal A is a transmitting light source A, and the photoelectric detection module of the communication terminal A is a photoelectric detection module A; the emitting light source of the communication terminal B is an emitting light source B, and the photoelectric detection module of the communication terminal B is a photoelectric detection module B; emitting light source A and emitting light source B adopt the light source of different wave bands, and photoelectric detection module A's receiving terminal is equipped with the filter A that corresponds with emitting light source A's light source wave band, and photoelectric detection module B's receiving terminal is equipped with the filter B that corresponds with emitting light source B's light source wave band, avoids the self-luminous from the self-interference problem of receiving, promotes the reliability and the stability of communication.
The signal light sources in the emission light source controlled by time division multiplexing can adopt different wave bands, and are provided with photoelectric detectors corresponding to the number of the wave bands of the emission light source, the wave bands can be selected in the range of 400nm-700nm according to different application scenes, the blue light wave band or the green light wave band can be selected for underwater pure water area communication, the red light wave band can be selected for underwater turbid water area communication, the white light can be selected for indoor communication, two or more wave band light source arrays can be selected for a certain application scene, and the like.
As shown in fig. 4, the emission light source of each communication terminal is an array light source, each emission light source includes a plurality of signal light sources 1, a lens for adjusting the divergence angle of the signal light source 1 is arranged at the front end of the signal light source 1, the divergence angle of the signal light source 1 is adjusted by adjusting the distance between the lens and the signal light source 1, each signal light source 1 includes a plurality of sub-array light sources, the sub-array light sources are LD or LED light sources, preferably LD light sources, the transmission efficiency is high, the requirement of medium-distance and long-distance communication is met, the adjustment range of the divergence angle of the light beam can reach 10 to 45 °, the number of the array light sources and the arrangement rule can be changed according to the application scene, the arrangement rule of the array light sources can be arranged in a circular, square, triangular or the like according to; the transmitting light source adopts four array light sources, the filter plate 2 is positioned in the center of the end face of the communication terminal, the signal light sources 1 are uniformly distributed around the filter plate 2, each signal light source comprises 3 sub-array light sources, the four array light sources can transmit the same signal at the same time, the transmitting power is improved, and the time division multiplexing technology is also supported, each signal light source 1 emits light according to a set non-overlapping time sequence, different information is transmitted, so that the communication speed is improved by four times on the basis of the communication speed of a single light source, the photoelectric detection module adopts a photoelectric detector to receive the light signals, and the photoelectric detector preferably selects a high-sensitivity PMT or APD.
As shown in fig. 1, 5 and 6, the communication method of the visible light bidirectional high-speed communication system includes the steps of:
s01, firstly, the communication terminal A and the communication terminal B are always in a receiving and sending state, the upper computer A controls the information sending module of the communication terminal A to continuously send a handshake request signal through the automatic control module, the information receiving module of the communication terminal B receives the handshake request signal and then transmits the handshake request signal to the lower computer A, the lower computer A sends a handshake feedback signal through the information sending module of the communication terminal B, the communication terminal A stops sending a handshake request after receiving the handshake feedback signal, and the communication terminal A and the communication terminal B establish a communication link; the communication link between the communication terminal B and the communication terminal a can be established by the same principle between the upper computer B and the lower computer B, and the process of establishing the communication link is shown in fig. 5.
And S02, after the communication link is established, the automatic control module controls the communication terminal A and the communication terminal B to send and receive information mutually, and unidirectional or bidirectional information transmission is carried out.
In step S02, the communication terminal sending information controls the corresponding signal light sources 1 to emit light simultaneously through the time division multiplexing module by the driving module to transmit the same signal, or the communication terminal sending information controls the corresponding signal light sources 1 to emit light sequentially according to a predetermined non-overlapping time sequence by the driving module to perform time division multiplexing processing on the information to be transmitted through the time division multiplexing module by the driving module to transmit the signal to another communication terminal.
The processing method of time division multiplexing comprises the following steps:
1) recording the total number of the signal light sources 1 as n, numbering the signal light sources 1 of each group of emission light sources, and sequentially recording the signal light sources 1 as n1、n2、n3……nn(ii) a Firstly, a lead code module adds a lead code M in front of pulse modulation information output by a modulation module to form serial data streams, each serial data stream comprises a plurality of modulation units t, each modulation unit is divided into a plurality of effective modulation units tau, the lead code M is used for identifying each group of signals needing to be transmitted, a time division multiplexing module carries out coding counting on the number of the effective modulation units tau in the serial data streams through a coding counter, the counting value N of the coding counter is less than or equal to the number N of signal light sources 1 contained in each emission light source, wherein N represents the number of the effective modulation units tau needing to be transmitted in each modulation unit, and N is greater than or equal to 1 and less than or equal to N;
2) the time division multiplexing module extracts the effective modulation unit tau with the code count of 11Will tau be1To n1The driving module corresponding to the signal light source extracts the effective modulation unit tau with the code count of 22Will tau be2To n2A driving module corresponding to the signal light source extracts the effective modulation unit tau with the code count of N by analogy in turnNWill tau beNTo nNThe driving module corresponding to the signal light source finally forms N groups of optical signals to be emitted;
3) the photoelectric detection module of the information receiving module receives N groups of optical signals and converts the optical signals into electric signals, after the electric signals are processed by the small signal amplification circuit and the automatic gain control circuit, the synchronization module identifies a lead code M of the electric signals, realizes bit synchronization by pulse characteristics and a lead code element, then matches the lead code element with a code length to complete frame synchronization, demodulates and decodes the electric signals, and sends the electric signals to the automatic control module;
4) and the automatic control module detects whether a lost frame or an invalid frame exists in the signal, controls the communication terminal to send a lost frame retransmission request until the information is complete, and finishes information transmission, wherein the process is shown in fig. 1.
As shown in fig. 6For the emitting light source in fig. 4 of the present invention, a time division multiplexing technique is adopted, assuming that a signal to be transmitted includes 5 modulation units t, the emitting light source includes 4 independent signal light sources 1, n =4, and the signal light source 1 is according to n1~n4Numbering, dividing each modulation unit into 4 effective modulation units, and dividing the 4 effective modulation units according to the number tau1~τ4Numbering, 5 rounds of numbering can be carried out, and the number tau is numbered1Is sent to the signal light source n1Number τ2Is sent to the signal light source n2Number τ3Is sent to the signal light source n3Number τ4Is sent to the signal light source n4The signal received by each signal light source 1 is shown in fig. 6.
After a communication link is established, an upper computer A can send an information request to a communication terminal B through an information sending module of the communication terminal A, after the communication terminal B receives the information request, the upper computer B converts the acquired information into an optical signal to be sent to the communication terminal A through a coding module, a modulation module, a lead code module, a time division multiplexing module, a driving module and a transmitting light source A of the communication terminal B in sequence, the communication terminal A restores the information through a photoelectric detection module A, a small signal amplification circuit, an automatic gain control circuit, a synchronization module, a demodulation module and a decoding module, and sends the information to a lower computer B to be displayed, so that one-way communication is realized; or the communication terminal B sends an information request to the communication terminal A, and the communication terminal A sends information to the communication terminal B after receiving the information request.
Or after a communication link is established, in order to improve the communication efficiency and save the working time, information transmission can be directly carried out between communication terminals without sending information requests, the upper computer B converts the collected information into optical signals through the coding module, the modulation module, the lead code module, the time division multiplexing module, the driving module and the transmitting light source B of the communication terminal B and sends the optical signals to the communication terminal A, and the communication terminal A restores the information through the photoelectric detection module A, the small signal amplification circuit, the automatic gain control circuit, the decoding module and the demodulation module and sends the information to the lower computer B for display; the upper computer A transmits information to a lower computer of the communication terminal B through the communication terminal A, so that the two communication terminals alternately transmit information to carry out semi-bidirectional communication; and both the two communication terminals can receive external information while sending the information to the outside, so that bidirectional communication is carried out, and the communication of the two communication terminals cannot interfere with each other.
The transmitting light source of the communication terminal can simultaneously transmit the same signal to enhance the transmitting power according to the requirement, the requirement of long-distance communication is met, or in short-distance communication, only part of the signal light sources 1 are started, the condition that the receiving saturation is caused by overhigh optical power and the communication fails is avoided, when the information quantity needing to be transmitted is large, the time division multiplexing module is utilized, the signal light sources 1 are controlled to emit light according to the set non-overlapping time sequence, different information is transmitted, and efficient information transmission is carried out.
In the communication process, the automatic control module detects whether the information received by the communication terminal has a lost frame or an invalid frame, and is provided with an error detection and correction mechanism and an error retransmission mechanism to control the communication terminal to send a lost frame retransmission request until the received information is completely supplemented.
The following are two different application scenarios of the present invention:
example 1: the application scene is deep sea high-speed communication, the communication terminal A is carried on an underwater 2000-meter unmanned aerial vehicle A, the communication terminal B is carried on an underwater 2000-meter unmanned aerial vehicle B, the communication terminal A and the communication terminal B are horizontally opposite, the distance is 100 meters, and the communication speed is 100 Mbps. The design scheme in this application scenario is as follows.
The emitting light source a of the communication terminal a selects a blue LD, the emitting light source B of the communication terminal B selects a green LD, the number of arrays of the communication terminal a and the communication terminal B is 4, each array light source includes 3 sub-array light sources, as shown in fig. 4 of the present invention. RS codes are selected by coding modules of two communication terminals, OOK modulation is selected as a modulation mode of a modulation module, the modulation rate of each path of signal light source is set to be 25Mbps, namely each path of signal light source modulation unit t is 40ns and represents 1bit code element information, the modulation unit t is divided into 4 effective modulation units tau, the length of each effective modulation unit tau is 10ns, pulse modulation information of a first effective modulation unit is selected and sent to a signal light source 1, pulse modulation information of a second effective modulation unit is selected and sent to a signal light source 2, pulse modulation information of a third effective modulation unit is selected and sent to a signal light source 3, and pulse modulation information of a fourth effective modulation unit is selected and sent to the signal light source 4; the speed and power control interface sets the time division multiplexing path number to be 4, a Barker code synchronization code element is added in the lead code module, a photoelectric detector at a receiving end selects a PMT (photoelectric detector), blue light is detected, and a pressure-resistant and sealed communication terminal cavity shell is designed. The down-sending of the information to be transmitted and the up-transmitting interface of the demodulation information are network ports.
After the communication terminal A loads information to be sent, the transmitting terminal sends out flashing blue light, and the comprehensive communication rate is 100 Mbps. The human eye cannot effectively distinguish due to the excessively high communication rate. The output electric signal of the detector at the receiving end is measured by an oscilloscope or a pulse monitoring means to meet the communication rate of 100Mbps, and the visible data flow is 100Mbps through the monitoring of the network port flow at the receiving end.
Example 2:
the application scene is indoor communication, the communication terminal A and the communication terminal B are respectively carried on the mobile trolley to move from far to near relatively, the relative speed is 0.5m/s, and communication in motion is realized between the two communication terminals in the moving process. In order to ensure a good communication effect, the communication rate needs to be flexibly adjusted, and communication failure caused by optical power saturation along with the approach of the distance needs to be avoided. The design scheme in this application scenario is as follows.
The number of the emitting light sources of the two communication terminals is 4, each array light source comprises 2 sub-array light sources, the emitting light source A selects a white light LED, the emitting light source B adopts a red light LED, the light power of each sub-array LED is 1W, the modulation mode of the modulation module selects OOK modulation, the modulation format is consistent with that of the embodiment 1, and in the process that the communication terminal A and the communication terminal B approach to each other, the rate and power control interface periodically changes the maximum value N of the time division multiplexing module coding counter to adjust the communication rate and the emitting power. For example, the initial value of N is 4, and the value of N is reduced by 1 every 10s, so that the communication rate is initially 100Mbps, and the communication rate is relatively reduced by 25Mbps every 5m of relative movement; the transmitting power is initially 12W, the transmitting power is relatively reduced by 3W for every 5m of relative movement until the distance is very close, and the communication rate of the lowest transmitting power of 3W and 25Mbps is kept. The communication process accomplishes dynamic adjustment of the rate and dynamic adjustment of the emitted optical power.
The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.
Claims (10)
1. A visible light bidirectional high-speed communication system is characterized in that: the communication terminal comprises an information sending module and an information receiving module, wherein the information sending module is used for receiving information transmitted by an upper computer and converting the information into optical signals to be sent out, the information sending module comprises a coding module, a modulation module, a driving module and a transmitting light source which are connected in sequence, the information receiving module is used for receiving the optical signals and converting the optical signals into electric signals to be sent to a lower computer, and the information receiving module comprises a photoelectric detection module, a small signal amplification circuit, an automatic gain control circuit, a demodulation module and a decoding module which are connected in sequence;
the coding module is used for coding the information sent by the upper computer;
the modulation module is used for carrying out pulse modulation on the output signal of the coding module;
the driving module comprises a transmitting light source for converting signals into optical signals;
the transmitting light source is used for transmitting the converted optical signal to an information receiving module of another communication terminal;
the photoelectric detection module is used for receiving optical signals and converting the optical signals into electric signals;
the small signal amplifying circuit is used for enhancing the signal-to-noise ratio of the electric signal converted by the photoelectric detection module;
the demodulation module and the decoding module are used for demodulating and decoding the electric signals.
2. The bidirectional high-speed communication system according to claim 1, wherein: emitting light source adopts the array light source, and every emitting light source includes independent signal light source (1) of a plurality of, and drive module's quantity is corresponding with the quantity of signal light source (1), and 1 signal light source (1) of every drive module drive, photoelectric detection module adopt photoelectric detector, and photoelectric detector's receiving terminal sets up and is used for carrying out filterable filter (2) to the light signal, and signal light source (1) equipartition is around filter (2).
3. The bidirectional high-speed communication system according to claim 2, wherein: each signal light source (1) comprises a plurality of sub-array light sources, and a lens for adjusting the divergence angle is arranged at the front end of each signal light source (1).
4. The bidirectional high-speed communication system according to claim 2, wherein: a lead code module and a time division multiplexing module are arranged between the modulation module and the driving module, and a synchronization module is arranged between the automatic gain control circuit and the demodulation module;
the lead code module is used for adding a lead code of identification data to the data front end output by the modulation module;
the time division multiplexing module is used for carrying out time division multiplexing processing on the data output by the lead code module and transmitting the data to the driving module to be converted into optical signals to be transmitted out, the time division multiplexing module is provided with a control interface for controlling the signal transmission rate and power, and the time division multiplexing module comprises a coding counter for coding and counting the signals;
the synchronization module is used for identifying the lead code of the electric signal output by the photoelectric detection module and carrying out bit synchronization and frame synchronization.
5. The bidirectional high-speed communication system according to claim 4, wherein: the communication terminal is divided into a communication terminal A and a communication terminal B, wherein the emission light source of the communication terminal A is an emission light source A, and the photoelectric detection module of the communication terminal A is a photoelectric detection module A; the transmitting light source of the communication terminal B is a transmitting light source B, the photoelectric detection module of the communication terminal B is a photoelectric detection module B, and the transmitting light source A and the transmitting light source B adopt light sources with different wave bands.
6. The bidirectional high-speed communication system according to claim 5, wherein: the receiving end of the photoelectric detection module A is provided with a filter A corresponding to the light source wave band of the emission light source A, and the receiving end of the photoelectric detection module B is provided with a filter B corresponding to the light source wave band of the emission light source B.
7. The communication method of the visible light bidirectional high-speed communication system according to any one of claims 1 to 6, characterized in that: the method comprises the following steps:
s01, firstly, the automatic control module controls the information sending module of the communication terminal A to continuously send a handshake request signal, after the communication terminal B receives the handshake request signal, the information sending module of the communication terminal B sends a handshake feedback signal, after the communication terminal A receives the handshake feedback signal, the communication terminal A stops sending the handshake request, and the communication terminal A and the communication terminal B establish a communication link;
and S02, after the communication link is established, the automatic control module controls the communication terminal A and the communication terminal B to send and receive information mutually, and unidirectional or bidirectional information transmission is carried out.
8. The method of claim 7, wherein the method comprises: in step S02, the communication terminal sending the information controls the corresponding signal light sources (1) to emit light simultaneously through the driving module by the time division multiplexing module to transmit the same signal.
9. The method of claim 7, wherein the method comprises: in step S02, the communication terminal that sends the information performs time division multiplexing processing on the information to be transmitted through the time division multiplexing module, and the time division multiplexing module controls the corresponding signal light sources (1) to sequentially emit light according to a predetermined non-overlapping time sequence through the driving module, and transmits the signal to another communication terminal.
10. The method of communication in a bidirectional high-speed communication system using visible light according to claim 9, wherein: the time division multiplexing processing method comprises the following steps:
1) recording the total number of the signal light sources (1) as n, numbering the signal light sources (1) of each group of emission light sources, and sequentially recording the signal light sources (1) as n1、n2、n3……nn(ii) a Firstly, a lead code module adds a lead code M in front of pulse modulation information output by a modulation module to form serial data streams, each serial data stream comprises a plurality of modulation units t, each modulation unit is divided into a plurality of effective modulation units tau, the lead code M is used for identifying each group of signals needing to be transmitted, a time division multiplexing module carries out coding counting on the number of the effective modulation units tau in the serial data streams through a coding counter, the counting value N of the coding counter is less than or equal to the number N of signal light sources (1) contained in each emission light source, wherein N represents the number of the effective modulation units tau needing to be transmitted in each modulation unit, and N is more than or equal to 1 and less than or equal to N;
2) the time division multiplexing module extracts the effective modulation unit tau with the code count of 11Will tau be1To n1The driving module corresponding to the signal light source extracts the effective modulation unit tau with the code count of 22Let τ be2To n2The driving module corresponding to the signal light source is analogized in turn to effectively modulate the unit tauNWill tau beNTo nNThe driving module corresponding to the signal light source finally forms N groups of optical signals to be emitted;
3) the photoelectric detection module of the information receiving module receives N groups of optical signals and converts the optical signals into electric signals, after the electric signals are processed by the small signal amplification circuit and the automatic gain control circuit, the synchronization module identifies lead codes of the electric signals, pulse characteristics and lead code elements to realize bit synchronization, then the lead code elements are matched with code lengths to complete frame synchronization, and the electric signals are demodulated, decoded and sent to the automatic control module;
4) and the automatic control module detects whether the signal has a lost frame or an invalid frame, controls the communication terminal to send a lost frame retransmission request until the information is complete, and completes the information transmission.
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