JP2012163431A - Visible light communication device, visible light communication method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a visible light communication device which calculates a distance between transmission/reception devices for visible light communication with high accuracy.SOLUTION: A visible light communication device comprises a reception unit, a delay time calculation unit and a distance calculation unit. The reception unit receives transmission data superimposed on visible light. The delay time calculation unit calculates delay time data indicating delay time of reception time in the reception means from transmission time of the transmission data. The distance calculation unit calculates distance data indicating a distance between a transmission position and a reception position for the transmission data based on the delay time data.

Description

  Embodiments described herein relate generally to a visible light communication apparatus that implements data communication using visible light.

  In recent years, LED lighting using LEDs (light emitting diodes) is becoming widespread. Since this LED illumination has excellent response characteristics and control characteristics, its use for visible light communication is promoted.

  Visible light communication is a communication method for realizing data communication by modulating illumination data (visible light) emitted from an LED lighting device or the like with a carrier wave. That is, visible light communication is a data communication method in which transmission data is superimposed on visible light and transmitted.

  Many lighting devices such as LED lighting devices are installed in buildings or on roads. Therefore, it is possible to easily realize visible light communication using an existing lighting device without newly preparing a light emitting facility for visible light.

JP 2006-317213 A

  Visible light communication using LED illumination is capable of visually confirming the direction of LED illumination as a transmission source, unlike a communication method using radio waves. Furthermore, it is possible to visually estimate the distance from the transmission source to the reception position (the position of the reception device). If this distance can be obtained with high accuracy, it is useful depending on the field of use of visible light communication.

  Therefore, it is required to realize a visible light communication device that calculates a distance between transmission / reception devices of visible light communication with high accuracy.

  According to this embodiment, the visible light communication apparatus includes a receiving unit, a delay time calculating unit, and a distance calculating unit. The receiving means receives transmission data superimposed on visible light. The delay time calculation means calculates delay time data indicating a delay time of the reception time at the reception means with respect to the transmission time of the transmission data. The distance calculation means calculates distance data indicating a distance between the transmission position and the reception position of the transmission data based on the delay time data.

The block diagram for demonstrating the structure of the visible light communication system regarding 1st Embodiment. The timing chart for demonstrating operation | movement of the data receiver regarding 1st Embodiment. The block diagram for demonstrating the structure of the data transmission apparatus regarding 1st Embodiment. The block diagram for demonstrating the structure of the data receiver regarding 1st Embodiment. The flowchart for demonstrating the procedure of the distance calculation process regarding 1st Embodiment. The block diagram for demonstrating the structure of the visible light communication system regarding 2nd Embodiment. The timing chart for demonstrating operation | movement of the data transmitter / receiver regarding 2nd Embodiment. The block diagram for demonstrating the structure of the data transmitter / receiver regarding 2nd Embodiment. The flowchart for demonstrating the procedure of the distance calculation process regarding 2nd Embodiment. The block diagram for demonstrating the structure of the visible light communication system regarding 3rd Embodiment. The timing chart for demonstrating operation | movement of the data receiver regarding 3rd Embodiment. The block diagram for demonstrating the structure of the data transmitter regarding 3rd Embodiment. The block diagram for demonstrating the structure of the data receiver regarding 1st Embodiment. The flowchart for demonstrating the procedure of the distance calculation process regarding 3rd Embodiment.

  Embodiments will be described below with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram illustrating a configuration of a visible light communication system according to the present embodiment.

  As shown in FIG. 1, the visible light communication system includes a data transmission device 10 and a data reception device 20. The visible light communication system of this embodiment can be applied to, for example, a system that performs visible light communication between a vehicle and an illumination lamp on a road, a system that performs visible light communication between a ship and a lighthouse, and the like.

  The data transmission device 10 transmits data (may be referred to as visible light data) using visible light 200 from an LED illuminator 11 using an LED (light emitting diode) element as a carrier wave. Here, the data transmitter 10 performs baseband visible light transmission in which digital transmission data is directly superimposed on a carrier wave that is visible light 200. The data transmission device 10 is incorporated in an illuminating lamp on a road having an LED illuminator 11, for example.

  The data receiving device 20 receives the visible light 200 by the light receiving element 21 such as a photo sensor or a CMOS sensor, and demodulates and outputs the transmission data superimposed on the visible light 200. The data receiving device 20 is mounted on, for example, a vehicle traveling on a road.

  In the present embodiment, each of the data transmission device 10 and the data reception device 20 includes GPS receivers 12 and 22 that receive GPS signals transmitted from a GPS (global positioning system) artificial satellite 100. Each of the data transmission device 10 and the data reception device 20 acquires high-precision clock data included in GPS signals received by the GPS receivers 12 and 22. That is, the data transmission device 10 and the data reception device 20 each perform a transmission / reception operation in synchronization with the clock data of the GPS signal.

(Data transmission device and data reception device)
FIG. 3 is a block diagram illustrating a main part of the data transmission device 10.

  The data transmission device 10 includes a clock processing unit 13, a synchronization timing generation unit 14, a transmission data creation unit 15, a modulation unit 16, a transmission data output unit 17, an LED drive unit 18, and a power supply unit 19. .

  The clock processing unit 13 includes a clock circuit, extracts clock data from the GPS signal received by the GPS receiver 12, adjusts and outputs clock data output from the clock circuit based on the clock data. The synchronization timing generation unit 14 generates a synchronization transmission timing signal based on the clock data output from the clock processing unit 13. The transmission data output unit 17 outputs transmission data (visible light data) to the LED driving unit 18 at a transmission timing set in advance with the data reception device 20 in synchronization with the synchronous transmission timing signal.

  The transmission data creation unit 15 creates a predetermined transmission data frame from transmission data TD transferred from a server (not shown), for example. The modulation unit 16 outputs transmission data (visible light data) obtained by modulating the transmission data frame created by the transmission data creation unit 15 for visible light communication.

  The LED drive unit 18 controls the drive current of the LED illuminator 11 according to transmission data (visible light data) output from the transmission data output unit 17 at a preset transmission timing. Thereby, the LED illuminator 11 emits visible light 200 on which transmission data TD (visible light data) is superimposed. The power supply unit 19 supplies power to the LED drive unit 18 and the other elements 13 to 17.

  FIG. 4 is a block diagram showing a main part of the data receiving apparatus 20.

  The data reception device 20 includes a clock processing unit 23, a synchronization delay calculation unit 24, a distance calculation unit 25, a demodulation unit 26, a data output unit 27, a data input unit 28, an electric signal conversion unit 29, a power supply Part 30.

  The clock processing unit 23 includes a clock circuit, extracts clock data from the GPS signal received by the GPS receiver 22, adjusts and outputs the clock data output from the clock circuit based on the clock data. The synchronization delay calculation unit 24 compares the transmission timing (GPS reception synchronization signal GS) preset based on the clock data with the reception timing of the data signal output from the data input unit 28, and calculates the delay time T. calculate.

  The distance calculation unit 25 calculates the distance between the data transmission device 10 and the data reception device 20 based on the delay time T calculated by the synchronization delay calculation unit 24, and outputs the distance data DD. The synchronization delay calculation unit 24 and the distance calculation unit 25 are composed of a microprocessor and software.

  The electric signal converter 29 converts the visible light 200 received by the light receiving element 21 into an electric signal. The data input unit 28 performs signal processing such as waveform shaping processing and noise removal processing on the electrical signal from the electrical signal conversion unit 29, and extracts a data signal for restoring visible light data (transmission data). The demodulator 26 demodulates visible light data (transmission data) from the data signal from the data input unit 28. The data output unit 27 converts the transmission data demodulated by the demodulation unit 26 into reception data RD having a predetermined format such as characters and images and outputs the data. The power supply unit 30 supplies power to the electric signal conversion unit 29 and the other elements 23 to 28.

(Transmission / reception operation and distance calculation processing)
Hereinafter, with reference to the timing chart of FIG. 2 and the flowchart of FIG.

  First, the data transmission device 10 emits visible light 200 on which transmission data TD (visible light data) is superimposed from the LED illuminator 11. At this time, as described above, the data transmission device 10 synchronizes with the synchronous transmission timing signal generated based on the clock data of the GPS signal, and transmits the transmission data at a transmission timing set in advance with the data reception device 20. (Visible light data) is transmitted.

  On the other hand, the data receiving device 20 receives the visible light 200 transmitted by the light receiving element 21, and extracts a data signal for restoring visible light data (transmission data) by the data input unit 28. That is, as shown in FIG. 5, the data receiving device 20 receives visible light data synchronized with the clock data of the GPS signal (step S1). The data receiving device 20 demodulates the visible light data (transmission data TD) by the demodulator 26 and outputs the received data RD from the data output unit 27 (step S2).

  Here, in the present embodiment, the data transmission device 10 and the data reception device 20 execute transmission and reception operations in synchronization with high-precision clock data from the GPS receivers 12 and 22, respectively. The data transmission device 10 transmits transmission data (visible light data) at a transmission timing set in advance with the data reception device 20 based on the clock data of the GPS signal.

  In the data reception device 20, the synchronization delay calculation unit 24 acquires a transmission timing set in advance based on the clock data of the GPS signal as the GPS reception synchronization signal GS, as shown in FIG. Thereby, the synchronization delay calculation unit 24, as shown in FIG. 2, delay time data indicating the delay time T between the transmission timing (GPS reception synchronization signal GS) and the actual reception timing (visible light synchronization reception data RD). Is calculated (step S3).

  Further, in the data reception device 20, the distance calculation unit 25 calculates the distance between the data transmission device 10 and the data reception device 20 based on the delay time T calculated by the synchronization delay calculation unit 24 (step S4). Specifically, the distance calculation unit 25 calculates the distance data DD by a calculation formula “delay time T × space propagation speed C = distance (m)”. Here, the space propagation speed C is the propagation speed of the visible light 200.

  As described above, according to the visible light communication system of the present embodiment, the data reception device 20 includes the distance data DD together with the reception data RD corresponding to the transmission data TD (visible light data) transmitted from the data transmission device 10. Is calculated and output (step S5). The distance data DD is data indicating the distance between the data transmission device 10 and the data reception device 20.

  When the visible light communication system of the present embodiment is applied to, for example, a system that performs visible light communication between a vehicle and an illuminating lamp on a road, the data receiving device 20 mounted on the vehicle has a moving vehicle and visible light. The distance to the illuminating lamp that transmits data can be output. The data transmitter 10 provided in the illuminating lamp can transmit the position information of the illuminating lamp using visible light data. For this reason, the moving vehicle can recognize the change in the distance with respect to the position (fixed position) of the illuminating lamp in real time, and can grasp, for example, the time that can reach the position of the illuminating lamp. Such effects are the same even when the visible light communication system of the present embodiment is applied to a system that performs visible light communication between a ship and a lighthouse, for example.

  Moreover, when the visible light communication system of this embodiment is applied to a system that performs visible light communication between a plurality of vehicles, for example, a change in the distance between the vehicles can be output in real time. Therefore, for example, it is possible to construct a collision avoidance system that automatically reduces the vehicle speed by detecting that the approaching distance exceeds the allowable range based on the distance data DD. If such a collision avoidance system is mounted on a vehicle, collision avoidance between the vehicles can be realized.

  In the present embodiment, the case where the transmitting / receiving devices 10 and 20 use clock data synchronized based on the GPS signal has been described. However, radio clock data may be used instead of the GPS signal. However, in general, the radio clock data is less accurate than the clock data included in the GPS signal.

  Further, when transmitting data, the data transmission device 10 may add transmission time data indicating the next transmission time in advance to the transmission data in advance. As a result, the data receiving device 20 can accurately acquire the transmission timing.

[Second Embodiment]
FIG. 6 is a diagram illustrating a configuration of the visible light communication system according to the present embodiment.

  As shown in FIG. 6, the visible light communication system according to the present embodiment is composed of one (for convenience, A side) data transmission / reception device 40A and the other (for convenience, B side) data transmission / reception device 40B. Yes.

  The A-side data transmitting / receiving apparatus 40A transmits data (visible light data) using visible light 300A from an LED illuminator 41A using an LED (light emitting diode) element as a carrier wave. The A-side data transmitting / receiving apparatus 40A receives the visible light 300B by the light receiving element 42A such as a photo sensor or a CMOS sensor, and demodulates and outputs the transmission data superimposed on the visible light 300B.

  Similarly, the data transmission / reception device 40B on the B side transmits data (visible light data) using visible light 300B from the LED illuminator 41B using an LED (light emitting diode) element as a carrier wave. The B-side data transmitting / receiving device 40B receives the visible light 300A by the light receiving element 42B such as a photo sensor or a CMOS sensor, and demodulates and outputs the transmission data superimposed on the visible light 300A.

(Data transceiver)
FIG. 8 is a block diagram showing a main part of the data transmitting / receiving apparatuses 40A and 40B. Since both have the same configuration, the case of the data transmitting / receiving apparatus 40A on the A side will be described for convenience.

  As shown in FIG. 8, the data transmitting / receiving apparatus 40A includes a transmission data creation unit 43A, a modulation unit 44A, a transmission data output unit 45A, an LED drive unit 46A, a delay time calculation unit 47A, and a distance calculation unit 48A. An electric signal conversion unit 49A, a data input unit 50A, a demodulation unit 51A, a reception data output unit 52A, and a delay control unit 53A.

  For example, the transmission data creation unit 43A creates a predetermined transmission data frame from transmission data TD-A transferred from a server (not shown). The modulation unit 44A outputs transmission data (visible light data) obtained by modulating the transmission data frame created by the transmission data creation unit 43A for visible light communication. The transmission data output unit 45A outputs the transmission data modulated by the modulation unit 44A or reply data described later to the LED drive unit 46A. In the case of reply data, the transmission data output unit 45A outputs the reply data to the LED drive unit 46A via a preset fixed delay time after data reception based on the control of the delay control unit 53A.

  The LED drive unit 46A controls the drive current of the LED illuminator 41A according to transmission data or return data from the transmission data output unit 45A. Accordingly, the LED illuminator 41A emits visible light 300A on which transmission data or reply data is superimposed. The electric signal converter 49A receives the visible light 300B by the light receiving element 42A and converts the received light signal into an electric signal.

  The data input unit 50A performs signal processing such as waveform shaping processing and noise removal processing on the electrical signal from the electrical signal conversion unit 49A, and extracts a data signal for restoring visible light data (transmission data). The demodulator 51A demodulates visible light data (transmission data) from the data signal from the data input unit 50A. The reception data output unit 52A converts the transmission data demodulated by the demodulation unit 51A into reception data RD-A having a predetermined format such as characters and images and outputs the data.

  The delay time calculation unit 47A calculates a delay time (transmission / reception delay time T) between the data transmission timing from the transmission data output unit 45A and the reception timing (reply data) from the data input unit 50A. The distance calculation unit 48A calculates the distance to the data transmission / reception device 40B based on the transmission / reception delay time T calculated by the delay time calculation unit 47A, and outputs the distance data DD. The delay time calculation unit 47A and the distance calculation unit 48A are configured by a microprocessor and software.

(Transmission / reception operation and distance calculation processing)
Hereinafter, the data transmission / reception operation and the distance calculation process of this embodiment will be described with reference to the timing chart of FIG. 7 and the flowchart of FIG.

  As shown in FIG. 7, the data transmitter / receiver 40A transmits transmission data TD-A superimposed on the visible light 300A emitted from the LED illuminator 41A (step S11). The other data transmitter / receiver 40B receives the visible light 300A transmitted from the data transmitter / receiver 40A by the light receiving element 42B, demodulates the transmission data TD-A, and outputs received data RD-B (see FIG. 8). . In this case, as shown in FIG. 7, the transmission timing of the transmission data TD-A and the reception timing of the reception data RD-B have a spatial delay time z corresponding to the spatial light propagation speed.

  In the present embodiment, the other data transmission / reception device 40B creates reply data corresponding to the reception data RD-B by the transmission data creation unit (43B), and superimposes it on the visible light 300B emitted from the LED illuminator 41B. Transmit as data TD-B. At this time, the reply data (transmission data TD-B) is transmitted with a delay of a preset fixed delay time t after data reception based on the control of the delay control unit (53B).

  One data transmitter / receiver 40A receives the visible light 300B transmitted from the data transmitter / receiver 40B by the light receiving element 42A, demodulates the reply data (transmission data TD-B), and outputs it as received data RD-A (step). S12). Here, as shown in FIG. 7, in the data transmitting / receiving apparatus 40A, the delay time calculating unit 47A has a transmission / reception delay time T between the transmission timing of the transmission data TD-A and the reception timing of the return data (reception data RD-A). Is calculated (step S13). That is, the transmission / reception delay time T from the time when data is first transmitted from one data transmission / reception device 40A to the time when reply data is received from the other data transmission / reception device 40B is measured.

  Next, in the data transmission / reception device 40A, the distance calculation unit 48A calculates the distance from the data transmission / reception device 40B based on the transmission / reception delay time T calculated by the delay time calculation unit 47A (step S14). Specifically, the distance calculation unit 48A calculates the distance data DD by a calculation formula “(transmission / reception delay time T−fixed value circle time t) / 2 × space propagation speed C = distance (m)”. That is, the time excluding the predetermined fixed delay time t is the transmission delay time from the data transmitting / receiving apparatus 40A to the data transmitting / receiving apparatus 40B and the reply delay time in the opposite direction. Therefore, the round trip data communication delay time is obtained, and the distance between the data transmitting / receiving devices 40A and 40B can be obtained from the half value and the spatial light propagation speed C. In this case, it is possible to calculate the distance with high accuracy by correcting the communication delay time in consideration of the processing delay time of the electrical signal in each of the data transmitting / receiving apparatuses 40A and 40B.

  As described above, according to the visible light communication system of the present embodiment, the data transmitting / receiving apparatuses 40A and 40B output distance data DD indicating the distance to the other party, together with the reception data RD-A and RD-B, respectively. (Step S15). That is, each of the data transmitting / receiving devices 40A and 40B calculates distance data DD indicating the distance between each other based on the transmission / reception delay time between the transmission timing at which data is first transmitted and the reception timing of return data from the other party. it can.

  If the visible light communication system of the present embodiment is applied to a system that performs visible light communication between vehicles each equipped with a data transmitting / receiving device, each moving vehicle recognizes a change in distance between each other in real time. It becomes possible. Accordingly, it is possible to construct a collision avoidance system that detects that the approach distance between the vehicles exceeds the allowable range and automatically reduces the speed of the vehicle. If such a collision avoidance system is mounted on a vehicle, collision avoidance between the vehicles can be realized.

  Note that when transmitting data for the first time, the data transmitting / receiving apparatus 40A (or 40B) may add transmission time data indicating the next transmission time in advance to the transmission data in advance. Thereby, the data transmitter / receiver 40B (or 40A) can stabilize the timing of transmitting the reply data.

[Third Embodiment]
FIG. 10 is a diagram illustrating a configuration of the visible light communication system according to the present embodiment.

  As shown in FIG. 10, the visible light communication system includes a data transmission device 60 and a data reception device 80. The data transmitter 10 modulates and transmits transmission data using visible light 400 from an LED illuminator 61 that uses an LED (light emitting diode) element as a carrier wave. In parallel, the data transmitting apparatus 10 also modulates and transmits transmission data from the sound wave generator 62 using the sound wave 500 as a carrier wave.

  The data receiving device 80 receives the visible light 400 by the light receiving element 81 such as a photo sensor or a CMOS sensor, and demodulates and outputs transmission data (visible light data) superimposed on the visible light 400. Further, the data receiving device 80 receives a sound wave 500 by a sound receiving element 82 using a microphone or the like, and demodulates and outputs sound wave data superimposed on the sound wave 500.

(Data transmission device and data reception device)
FIG. 12 is a block diagram illustrating a main part of the data transmission device 60.

  The data transmission device 60 includes transmission data creation units 63 and 65, modulation units 64 and 66, transmission data output units 67 and 69, an LED drive unit 68, and a sound wave drive unit 70. The transmission data creation unit 63 creates a predetermined transmission data frame from visible light transmission data TD transferred from a server (not shown), for example. On the other hand, the transmission data creation unit 65 creates a transmission data frame from the sound wave transmission data ST transferred from a server (not shown).

  The modulation unit 64 modulates the transmission data frame (visible light transmission data TD) created by the transmission data creation unit 63 and outputs it to the transmission data output unit 67. The modulation unit 66 modulates the transmission data frame (sound wave transmission data ST) created by the transmission data creation unit 65 and outputs it to the transmission data output unit 69. The transmission data output units 67 and 69 operate in synchronization with the synchronization signal from the output synchronization unit 71 in order to output visible light data (visible light 400) and sound wave data (sound wave 500) simultaneously.

  The LED drive unit 68 controls the drive current of the LED illuminator 61 according to visible light transmission data (modulation data of the transmission data TD) output from the transmission data output unit 67. Thereby, the LED illuminator 61 emits visible light 400 on which the visible light transmission data is superimposed. The sound wave driving unit 70 drives and controls the sound wave generator 62 such as a speaker or an ultrasonic wave generator in accordance with sound wave transmission data (modulation data of the transmission data ST) output from the transmission data output unit 69. Thereby, the sound wave generator 62 generates a sound wave 500 on which the sound wave transmission data is superimposed.

  FIG. 13 is a block diagram showing a main part of the data receiving device 80.

  The data receiving device 80 includes an electric signal conversion unit 83, a data input unit 84, a demodulation unit 85, and a data output unit 86. The electric signal converter 83 converts the visible light 400 received by the light receiving element 81 into an electric signal. The data input unit 84 performs signal processing such as waveform shaping processing and noise removal processing on the electrical signal from the electrical signal conversion unit 83, and extracts a data signal for restoring visible light data. The demodulator 85 demodulates visible light data (transmission data TD) from the data signal from the data input unit 84. The data output unit 86 converts the transmission data demodulated by the demodulation unit 85 into reception data (visible light reception data) RD having a predetermined format such as characters and images, and outputs the data.

  On the other hand, the data receiving device 80 includes an electric signal conversion unit 87, a data input unit 88, a demodulation unit 89, and a data output unit 90. The electric signal converter 87 receives the sound wave 500 by the sound receiving element 82 such as a microphone and converts the sound wave signal into an electric signal. The data input unit 88 performs signal processing such as waveform shaping processing and noise removal processing on the sound wave signal (electric signal), and extracts a data signal for restoring the sound wave data. The demodulator 89 demodulates the sound wave data (transmission data ST) from the data signal from the data input unit 88. The data output unit 90 converts the transmission data demodulated by the demodulation unit 89 into reception data (sound wave reception data) SR having a predetermined format such as characters and images, and outputs the data.

  Further, the data receiving device 80 includes a delay time calculation unit 91 and a distance calculation unit 92. The delay time calculation unit 91 calculates a delay time T between the reception timing of visible light data from the data input unit 84 and the reception timing of sound wave data from the data input unit 88. The distance calculation unit 25 calculates the distance between the data transmission device 60 and the data reception device 80 based on the delay time T calculated by the delay time calculation unit 91, and outputs the distance data DD. Note that the delay time calculation unit 91 and the distance calculation unit 92 include a microprocessor and software.

(Transmission / reception operation and distance calculation processing)
Hereinafter, the data transmission / reception operation and the distance calculation process of this embodiment will be described with reference to the timing chart of FIG. 11 and the flowchart of FIG.

  First, the data transmission device 60 transmits visible light 400 on which visible light data (transmission data TD) is superimposed from the LED illuminator 61. Here, at the same time, the data transmission device 60 also transmits sound wave data (transmission data ST) from the sound wave generator 62 using the sound wave 500 as a carrier wave.

  On the other hand, the data receiving device 20 receives the visible light 400 transmitted by the light receiving element 81, and receives the sound wave 500 by the sound receiving element 82 (step S21). The data receiving device 20 demodulates the visible light transmission data and the sound wave data by the demodulation units 85 and 89 (step S22). Further, the data receiving device 20 outputs the visible light reception data RD from the data output unit 86 (step S23).

  As illustrated in FIG. 11, the delay time calculation unit 91 calculates a delay time T between the reception timing of the visible light reception data RD and the reception timing of the sound wave reception data SR (step S24). That is, the visible light reception data RD and the sound wave reception data SR are obtained by demodulating the visible light data and the sound wave data transmitted from the data transmission device 60 at the same transmission timing.

  The distance calculation unit 92 calculates the distance between the data transmission device 60 and the data reception device 80 based on the calculated delay time T (step S25). Specifically, the distance calculation unit 92 calculates the distance data DD by the calculation formula “delay time T × sound wave propagation speed P = distance (m)”. Here, the sound wave propagation speed P is the propagation speed of the sound wave 500. The data receiving device 80 outputs the distance data DD and the sound wave reception data SR (step S26). Here, the sound wave reception data SR is output after a delay time T compared to the visible light reception data RD.

  As described above, according to the visible light communication system of the present embodiment, the spatial propagation speed P of the sound wave 500 is extremely slow with respect to the spatial light propagation speed C of the visible light 400, and thus the distance is calculated from the propagation speed difference. can do. In this case, the distance data DD can be calculated with high accuracy by correcting the delay of the spatial light propagation velocity C from the calculated distance data DD.

  In the present embodiment, the sound wave 500 generated from the sound wave generator 62 may be a sound wave having a frequency that cannot be heard, such as an ultrasonic wave.

  Moreover, in the visible light communication system of this embodiment, visible light transmission data (TD) and sound wave transmission data (ST) are the data of the same content transmitted at the same timing. As a modification of the present embodiment, the sound wave transmission data (ST) may be data notifying the data content of the visible light transmission data (TD). In the case of the visible light communication system according to the present modification, for example, when applied to a system that distributes guide information as visible light transmission data (TD) from the data transmission device 60, the user receives data embedded in a portable device. The contents of the guidance information distributed as visible light transmission data (TD) can be recognized by voice by sound waves received by the device 80.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

10 ... Data transmission device, 11 ... LED illuminator, 12 ... GPS receiver,
20 ... Data receiver, 21 ... Light receiving element, 22 ... GPS receiver,
40A ... Data transmitting / receiving device, 41A ... LED illuminator, 42A ... Light receiving element,
40B ... Data transmitting / receiving device, 41B ... LED illuminator, 42B ... Light receiving element,
60 ... Data transmission device, 61 ... LED illuminator, 62 ... Sound wave generator,
80: Data receiving device, 81: Light receiving element, 82: Sound receiving element.

Claims (11)

Receiving means for receiving transmission data superimposed on visible light;
A delay time calculating means for calculating delay time data indicating a delay time of a reception time at the receiving means with respect to a transmission time of the transmission data;
A visible light communication apparatus comprising distance calculation means for calculating distance data indicating a distance between a transmission position and a reception position of the transmission data based on the delay time data. Having synchronization time acquisition means for acquiring time data for synchronizing with the transmission time from the outside,
The delay time calculating means includes
Obtaining transmission time data indicating the transmission time and reception time data indicating the reception time based on the time data,
The visible light communication apparatus according to claim 1, wherein the delay time data is calculated using the transmission time data and the reception time data. The synchronization time acquisition means includes
The visible light communication apparatus according to claim 2, wherein the visible light communication apparatus is configured to receive a time signal transmitted from a GPS or a radio clock system and generate the time data from the time signal. Having transmission means for transmitting transmission data superimposed on visible light;
The delay time calculating means includes
When receiving the reply data for the transmission data by the receiving means, the delay time data indicating a delay time of the reception time of the reply data with respect to the transmission time of the transmission data is calculated. The visible light communication apparatus according to claim 1. The distance calculating means includes
The distance data indicating the distance between the transmission position of the transmission data and the transmission position of the reply data with respect to the transmission data is calculated based on the delay time data. The visible light communication apparatus described. Visible light data receiving means for receiving transmission data superimposed on visible light;
Sound wave data receiving means for receiving sound wave data transmitted at the same timing as the transmission timing of the transmission data;
A delay time calculating means for calculating delay time data indicating a delay time between the reception timing of the visible light receiving means and the sound wave data receiving means;
A visible light communication apparatus comprising distance calculation means for calculating distance data indicating a distance between a transmission position and a reception position of the transmission data based on the delay time data. The distance calculating means includes
The visible light communication apparatus according to claim 6, wherein the distance data is calculated based on a spatial sound wave propagation speed of a sound wave carrying the delay time data and the sound wave data. A visible light communication system comprising: the visible light communication device according to claim 1; and a data transmission device that transmits transmission data superimposed on visible light to the visible light communication device.
A synchronization time acquisition means for acquiring a synchronization time of the reception operation of the visible light communication device and the transmission operation of the data transmission device;
The delay time calculating means of the visible light communication device is
A visible light communication system configured to calculate delay time data indicating a delay time between a transmission time of the data transmission device acquired by the synchronization time acquisition means and a reception time of the visible light communication device. A visible light communication system comprising first and second visible light transmission / reception devices including transmission means for transmitting transmission data superimposed on visible light and reception means for receiving the transmission data,
The first and second visible light transmitting / receiving devices are respectively
A delay time calculation means for calculating delay time data indicating a delay time of the reception time of the reply data with respect to a transmission time of the transmission data when the reception data is received by the reception means;
A visible light communication system comprising distance calculation means for calculating distance data indicating a distance between a transmission position and a reception position of the transmission data based on the delay time data. A visible light communication method applied to a visible light communication device having a receiving means for receiving transmission data superimposed on visible light,
A process of calculating delay time data indicating a delay time of a reception time at the reception unit with respect to a transmission time of the transmission data;
A visible light communication method for executing distance data indicating a distance between a transmission position and a reception position of the transmission data based on the delay time data. A program executed by a computer incorporated in a visible light communication device having a receiving means for receiving transmission data superimposed on visible light,
Means for calculating delay time data indicating a delay time of a reception time at the reception means with respect to a transmission time of the transmission data;
A program that operates as means for calculating distance data indicating a distance between a transmission position and a reception position of the transmission data based on the delay time data.

Images