Receiver device and receiving method

Abstract

To provide a receiver device capable of obtaining information safely.SOLUTION: A receiver device A2000 includes: one or more image sensors A8001-1 for acquiring image data and optical signals; and a processor A10001. The processor A10001 is configured to detect an object that includes the light source that has emitted the light signal by performing image processing on image data, acquire demodulated data by demodulating the optical signal, and store the demodulated data in memory A10002 while associating the same with the detected object.SELECTED DRAWING: Figure 43

Description

[Technical Field]

[0001] The present disclosure relates to a receiving device and a receiving method. [Background technology]

[0002] One method for obtaining information such as the location of a device, for example, to use services based on the device's location, is to use the Global Positioning System (GPS). In GPS-based methods, the device receives modulated signals transmitted from satellites and performs positioning calculations to estimate its own location. However, if it is difficult for the device to receive radio waves transmitted from satellites (for example, when indoors), it becomes difficult for the device to estimate its own location.

[0003] In such a case, one method for a terminal to estimate its own location is, for example, as disclosed in Non-Patent Document 1, in which the terminal estimates information such as its own location using radio waves transmitted from an access point (AP) of a wireless LAN (Local Area Network). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Bayesian based location estimation system using wireless LAN, Third IEEE Conference on Pervasive Computing and Commun. Workshops, pp.273-278, 2005. [Non-patent document 2] "High-Performance Image Sensors," Journal of the Institute of Image Information and Television Engineers, vol.66, no.3, pp.172-173, 2012. [Non-patent document 3] "Trends in High-Speed ​​Technology for CMOS Image Sensors," Journal of the Institute of Image Television Engineers, vol. 66, no. 3, pp. 174-177, 2012. [Non-patent document 4] "New Organic CMOS Image Sensor Suitable for Miniaturization of Pixel Size," FUJIFILM RESEARCH & DEVELOPMENT, no. 55, pp. 14-17, 2010. Summary of the Invention [Problem to be solved by the invention]

[0005] However, if a terminal does not have information such as the SSID (service set identifier) ​​of the access point it should access, it is not easy for the terminal to properly determine which access point to connect to from multiple access points in the vicinity. For this reason, for example, when a terminal connects to an access point to obtain information such as its own location, it may connect to an access point with an insecure SSID, posing a risk of information leakage.

[0006] One aspect of the present disclosure facilitates the provision of a receiving device or the like that can securely obtain information used by a terminal to identify an access point to which the terminal should connect, for example. [Means for solving the problem]

[0007] A receiving device according to one aspect of the present disclosure includes one or more image sensors that acquire image data and optical signals, and a processor, wherein the processor detects an object having a light source that transmitted the optical signal by performing image processing on the image data, obtains demodulated data by demodulating the optical signal, and stores the demodulated data in a memory in association with the detected object.

[0008] A receiving device according to one aspect of the present disclosure includes one or more image sensors that acquire image data and received signals, and a processor, wherein the processor detects an object by performing image processing on the image data, acquires demodulated data by demodulating the received signals, and stores the demodulated data in a memory in association with the detected object.

[0009] A receiving method according to one embodiment of the present disclosure is a receiving method performed by a receiving device equipped with one or more image sensors, which acquires an image and a received signal using the one or more image sensors, detects an object by performing image processing on the image data, demodulates the received signal to acquire demodulated data, and stores the demodulated data in memory in association with the detected object.

[0010] These comprehensive or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. [Effects of the Invention]

[0011] According to one aspect of the present disclosure, a terminal can securely obtain information.

[0012] Further advantages and benefits of certain aspects of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some of the embodiments and features described in the specification and drawings, but not all of them necessarily need to be provided to obtain one or more identical features. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating the principle of line scan sampling. [Figure 2] FIG. 2 is a diagram showing an example of an image captured with a long exposure time. [Figure 3] FIG. 3 is a diagram showing an example of an image captured with a short exposure time. [Figure 4A] FIG. 4A is a diagram illustrating 4PPM. [Figure 4B] FIG. 4B is a diagram illustrating the Manchester coding method. [Figure 5] FIG. 5 is a diagram illustrating an example of the configuration of a visible light communication system. [Figure 6] FIG. 6 is a diagram illustrating an example of a configuration of a communication system according to the first embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of a frame configuration according to the first embodiment. [Figure 8] FIG. 8 is a diagram showing the positional relationship between the device and the terminal according to the second embodiment. [Figure 9] FIG. 9 is a diagram illustrating an example of a configuration of a communication system according to the third embodiment. [Figure 10] FIG. 10 is a diagram showing a display example of the display unit according to the third embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of a frame configuration of a modulated signal transmitted by a first device according to the third embodiment. [Figure 12] FIG. 12 is a diagram illustrating an example of a frame configuration of a modulated signal transmitted by a base station according to the third embodiment. [Figure 13] FIG. 13 is a flowchart illustrating an example of processing in the communication system according to the third embodiment. [Figure 14] FIG. 14 is a diagram showing a display example of the display unit according to the third embodiment. [Figure 15] FIG. 15 is a diagram illustrating an example of a configuration of a communication system according to the fourth embodiment. [Figure 16] FIG. 16 is a diagram illustrating an example of a frame configuration of a modulated signal transmitted by a first device according to the fourth embodiment. [Figure 17] FIG. 17 is a diagram illustrating an example of a frame configuration of a modulated signal transmitted by a radio device of a terminal according to the fourth embodiment. [Figure 18] FIG. 18 is a flowchart illustrating an example of processing in the communication system according to the fourth embodiment. [Figure 19] FIG. 19 is a diagram illustrating an example of a configuration of a communication system according to the fifth embodiment. [Figure 20] FIG. 20 is a diagram illustrating an example of a frame configuration of a modulated signal including an SSID, which is transmitted by a third device according to the fifth embodiment. [Figure 21] FIG. 21 is a diagram illustrating an example of a frame configuration of a modulated signal including an encryption key, which is transmitted by a third device according to the fifth embodiment. [Figure 22] FIG. 22 is a flowchart illustrating an example of processing in the communication system according to the fifth embodiment. [Figure 23] FIG. 23 is a flowchart showing another example of processing in the communication system according to the fifth embodiment. [Figure 24] FIG. 24 is a diagram illustrating an example of a space in which a communication system according to the fifth embodiment is arranged. [Figure 25] FIG. 25 is a diagram illustrating a configuration example of a communication system according to the sixth embodiment. [Figure 26] FIG. 26 is a flowchart illustrating an example of processing in the communication system according to the sixth embodiment. [Figure 27] FIG. 27 is a diagram illustrating a configuration example of a communication system according to the seventh embodiment. [Figure 28] FIG. 28 is a diagram illustrating an example of a frame configuration of a modulated signal transmitted by a fifth device according to the seventh embodiment. [Figure 29] FIG. 29 is a diagram illustrating an example of a frame configuration of a modulated signal transmitted by a fifth device according to the seventh embodiment. [Figure 30] FIG. 30 is a diagram illustrating an example of a frame configuration of a modulated signal transmitted by a fifth device according to the seventh embodiment. [Figure 31] FIG. 31 is a diagram illustrating an example of a frame transmission method by the fifth device according to the seventh embodiment. [Figure 32] FIG. 32 is a diagram showing an example of a space in which a communication system according to the seventh embodiment is arranged. [Figure 33]FIG. 33 is a flowchart illustrating an example of processing in the communication system according to the seventh embodiment. [Figure 34] FIG. 34 is a diagram illustrating a configuration example of a communication device according to the eighth embodiment. [Figure 35] FIG. 35 is a diagram illustrating another example of the configuration of the communication device according to the eighth embodiment. [Figure 36] FIG. 36 is a diagram illustrating a first configuration example of a light receiving device according to the eighth embodiment. [Figure 37] FIG. 37 is a diagram illustrating a first configuration example of the received light signal processing unit according to the eighth embodiment. [Figure 38] FIG. 38 is a diagram illustrating a second configuration example of the received light signal processing unit according to the eighth embodiment. [Figure 39] FIG. 39 is a diagram illustrating an example of control of the image sensor according to the eighth embodiment. [Figure 40] FIG. 40 is a diagram illustrating a third example of the configuration of the received light signal processing unit according to the eighth embodiment. [Figure 41] FIG. 41 is a diagram illustrating a second configuration example of the light receiving device according to the eighth embodiment. [Figure 42] FIG. 42 is a diagram showing an example of performing line scan sampling in parallel in multiple regions. [Figure 43] FIG. 43 is a diagram illustrating an example of a physical configuration of a control unit according to the eighth embodiment. [Figure 44] FIG. 44 is a diagram illustrating an example of the configuration of a control unit according to the eighth embodiment. [Figure 45] FIG. 45 is a diagram illustrating another example of the configuration of the control unit according to the eighth embodiment. [Figure 46] FIG. 46 is a first diagram illustrating communication control based on an acquired image according to the eighth embodiment. [Figure 47] FIG. 47 is a second diagram illustrating communication control based on an acquired image according to the eighth embodiment. [Figure 48] FIG. 48 is a third diagram illustrating communication control based on an acquired image according to the eighth embodiment. [Figure 49]FIG. 49 is a fourth diagram illustrating communication control based on an acquired image according to the eighth embodiment. [Figure 50] FIG. 50 is a fifth diagram illustrating communication control based on an acquired image according to the eighth embodiment. [Figure 51] FIG. 51 is a sixth diagram illustrating communication control based on an acquired image according to the eighth embodiment. [Figure 52] FIG. 52 is a diagram showing an example of the configuration of another communication system that performs optical communication. [Figure 53] FIG. 53 is a diagram illustrating an example of the configuration of a transmitting device and a receiving device according to the tenth embodiment. [Figure 54] FIG. 54 is a diagram illustrating an example of the configuration of a transmitting device and a receiving device according to the tenth embodiment. [Figure 55] FIG. 55 is a diagram illustrating an example of a frame structure of an optical modulated signal according to the tenth embodiment. [Figure 56] FIG. 56 is a diagram illustrating an example of a reception state in the reception device according to the tenth embodiment. [Figure 57] FIG. 57 is a diagram showing an example of a symbol configuration according to the tenth embodiment. [Figure 58] FIG. 58 is a diagram showing another example of the symbol configuration according to the tenth embodiment. [Figure 59] FIG. 59 is a diagram illustrating another example of the reception state in the reception device according to the tenth embodiment. [Figure 60] FIG. 60 is a diagram illustrating another example of the reception state in the receiving device according to the tenth embodiment. [Figure 61] FIG. 61 is a diagram showing another example of the symbol configuration according to the tenth embodiment. [Figure 62] FIG. 62 is a diagram showing another example of the symbol configuration according to the tenth embodiment. [Figure 63] FIG. 63 is a diagram showing another example of the symbol configuration according to the eleventh embodiment. [Figure 64] FIG. 64 is a diagram illustrating an example of a configuration of a receiving device according to the eleventh embodiment. [Figure 65]FIG. 65 is a diagram illustrating another example of the configuration of the receiving device according to the eleventh embodiment. In FIG. [Figure 66] FIG. 66 is a diagram illustrating another example of the configuration of the receiving device according to the eleventh embodiment. [Figure 67] FIG. 67 is a diagram illustrating another example of the configuration of the receiving device according to the eleventh embodiment. [Figure 68] FIG. 68 is a diagram showing an example of a plurality of light sources provided in a vehicle. [Figure 69] FIG. 69 is a diagram showing an example of a plurality of light receiving units provided in a vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0015] [Example of the first visible light communication modulation and demodulation method] In this embodiment, an optical communication system is used in which modulated signals are transmitted and received as optical signals.

[0016] First, a first example of visible light communication, which is an example of an optical communication method applicable to each embodiment of the present disclosure, will be described.

[0017] <Line scan sampling> Smartphones, digital cameras, and the like are equipped with image sensors such as CMOS (Complementary Metal Oxide Semiconductor) sensors. Images captured by CMOS sensors do not necessarily capture the entire scene at exactly the same time. For example, as shown in Non-Patent Documents 2 and 3, a rolling shutter system is used to perform shutter operations for each row, reading out the amount of light received by the sensor for each line. Therefore, the start and end of light reception is controlled with a time lag for each line, taking into account the time required for readout. In other words, an image captured by a CMOS sensor is made up of a large number of overlapping lines with a slight time lag in the exposure period.

[0018] The first example of a visible light communication method realizes high-speed visible light signal reception based on a method that focuses on the properties of this CMOS sensor. That is, in the first example of a visible light communication method, by taking advantage of the fact that the exposure time varies slightly for each line, it is possible to measure the luminance and color of the light source at multiple points in time for each line from a single image (image captured by the image sensor), as shown in Figure 1, and to capture signals modulated at a speed faster than the frame rate.

[0019] Hereinafter, this sampling method will be referred to as "line scan sampling," and a row of pixels exposed at the same time will be referred to as an "exposure line."

[0020] Although "line scan sampling" can be realized using the rolling shutter method with a CMOS sensor, "line scan sampling" can also be performed in the same way by using a rolling shutter method with a sensor other than a CMOS sensor, such as a CCD (Charge-Coupled Device) sensor or an organic (CMOS) sensor such as that described in Non-Patent Document 4.

[0021] However, with the imaging settings for the camera function (video or still image shooting function), even if a rapidly blinking light source is captured, the blinking does not appear as a striped pattern along the exposure lines. This is because, with this setting, the exposure time is sufficiently longer than the blinking cycle of the light source, so as shown in Figure 2, the change in brightness due to the blinking of the light source (light emission pattern) is averaged out, reducing the change in pixel value between exposure lines and resulting in a nearly uniform image.

[0022] In contrast, as shown in FIG. 3, by setting the exposure time to approximately the blinking period of the light source, the blinking state (light-emitting pattern) of the light source can be observed as a change in brightness of the exposure line. In FIG. 3, the length of the exposure period is set slightly longer than the minimum period during which the same light-emitting state continues, and the difference in the start times of the exposure periods between adjacent exposure lines is set shorter than the minimum period during which the same light-emitting state continues. However, the setting of the exposure period in line scan sampling is not limited to this. For example, the length of the exposure period may be set shorter than the minimum period during which the same light-emitting state continues, or may be set to approximately twice the minimum period during which the same light-emitting state continues. Furthermore, optical communication methods may include not only a method in which the optical signal is expressed by a combination of square waves, as shown in FIG. 4A, but also a method in which the optical signal changes continuously. In either case, the receiving device of the optical communication method sets the difference in the start or end times of the exposure periods between temporally adjacent exposure lines to be equal to or shorter than the sampling interval corresponding to the sampling rate required to receive and demodulate the optical signal. Furthermore, the receiving device of the optical communication method sets the length of the exposure period to be equal to or shorter than the sampling interval. However, in the receiving device of the optical communication system, the length of the exposure period may be set to 1.5 times or less the sampling interval, or may be set to 2 times or less.

[0023] For example, the exposure lines are designed to be parallel to the long side of the image sensor. In this case, for example, if the frame rate is 30 fps (frames per second), a resolution of 1920 x 1080 pixels will provide 32,400 or more samples per second, and a resolution of 3840 x 2160 pixels will provide 64,800 or more samples per second.

[0024] <Application example of line scan sampling> While the above description focuses on line scan sampling, which reads out a signal indicating the amount of light received for each line, the optical signal sampling method using an image sensor such as a CMOS is not limited to this. Various methods that can acquire a signal sampled at a sampling rate higher than the frame rate used for normal video capture can be applied as the sampling method used for receiving the optical signal. For example, a global shutter method, which provides a shutter function for each pixel as shown in Non-Patent Documents 2 and 3, may be used to control the exposure period for each pixel to read out a signal, or a method that controls the exposure period for each group of multiple pixels arranged in a non-linear configuration to read out a signal. Alternatively, a method may be used in which a signal is read out from the same pixel multiple times within a period equivalent to one frame at the frame rate used for normal video capture.

[0025] <Frame Sampling> Furthermore, by using a frame rate method in which each pixel has a shutter function, as shown in Non-Patent Documents 2 and 3, it is possible to sample optical signals even in a method in which the frame rate is increased.

[0026] The embodiments described below can be realized using any of the methods already described, for example, "line scan sampling," "application of line scan sampling," and "frame sampling."

[0027] <Light source and modulation method> In visible light communication, for example, a light-emitting diode (LED) can be used as a transmitter. LEDs are becoming increasingly popular as light sources for lighting or display backlights, and can be made to blink at high speeds.

[0028] However, the light source used as a transmitter for visible light communication cannot be made to flicker freely for the purpose of visible light communication. If the change in brightness caused by visible light communication were noticeable to humans, it would impair the original function of the light source, such as lighting. Therefore, it is necessary to ensure that the transmitted signal does not flicker to the human eye and is illuminated at the desired brightness.

[0029] One modulation method that meets this requirement is called 4PPM (4-Pulse Position Modulation). 4PPM is a method that expresses two bits by combining the brightness of a light source four times, as shown in Figure 4A. Also, as shown in Figure 4A, 4PPM has three bright states and one dark state out of four, so the average brightness (average luminance) is 3 / 4 = 75%, regardless of the signal content.

[0030] For comparison, a similar method is the Manchester coding method shown in Figure 4B. The Manchester coding method expresses one bit using two states. Its modulation efficiency is 50%, the same as 4PPM. However, since one of the two states is bright and the other is dark, the average brightness is 1 / 2 = 50%. In other words, 4PPM is more suitable as a modulation method for visible light communication than the Manchester coding method. However, even if the brightness change caused by visible light communication is noticeable to humans, communication performance is not degraded. Therefore, depending on the application, there is no problem in using a method that produces brightness changes noticeable to humans. Therefore, the transmitter (light source) may generate a modulated signal and turn on and irradiate the light source using a modulation method such as ASK (Amplitude Shift Keying), PSK (Phase Shift Keying), or PAM (Pulse Amplitude Modulation).

[0031] <Example of overall configuration of communication system> As shown in Figure 5, a communication system that performs visible light communication includes at least a transmitter that transmits (irradiates) an optical signal and a receiver that receives (receives) the optical signal. For example, there are two types of transmitters: a variable optical transmitter that changes the transmission content depending on the video or content to be displayed, and a fixed optical transmitter that continues to transmit fixed transmission content. However, an optical communication system can also be configured with either a variable optical transmitter or a fixed optical transmitter.

[0032] The receiver receives the optical signal from the transmitter, and can obtain, for example, related information associated with the optical signal and provide it to the user.

[0033] Although the outline of the visible light communication method has been described above, the communication method applicable to the optical communication described in the following embodiments is not limited to the above method. For example, the light-emitting unit of the transmitter may transmit data using multiple light sources. Furthermore, the light-receiving unit of the receiving device may be a communication method that uses a device capable of converting optical signals into electrical signals, such as a photodiode, instead of an image sensor such as a CMOS. In this case, since sampling does not need to be performed using the above-mentioned line scan sampling, it is also applicable to methods that require 32,400 or more samples per second. Furthermore, depending on the application, a communication method using wireless frequencies other than visible light, such as infrared or ultraviolet, may also be used.

[0034] (Embodiment 1) FIG. 6 shows an example of the configuration of the device 100 and the terminal 150 according to this embodiment.

[0035] [Configuration of Device 100] The device 100 (corresponding to a transmitter of visible light communication) is equipped with a visible light source such as an LED (Light Emitting Diode), illumination, or light (collectively referred to as a light source). Note that, hereinafter, the device 100 may also be referred to as a "first device."

[0036] 6, the transmitter 102 receives, for example, information about a location or information about a position 101 as input. The transmitter 102 may also receive information about a time 105 as input. The transmitter 102 may also receive both information about a location or information about a position 101 and information about a time 105 as input.

[0037] The transmitter 102 receives location-related or position-related information 101 and / or time-related information 105 as input, generates an (optical) modulated signal 103 based on these input signals, and outputs the modulated signal 103. The modulated signal 103 is then transmitted from a light source 104, for example.

[0038] An example of location-related or position-related information 101 will now be described.

[0039] <Example 1> The location-related or position-related information 101 may be information about the latitude and / or longitude of the location / position. For example, information such as "45 degrees north latitude, 135 degrees east longitude" may be the location-related or position-related information 101.

[0040] <Example 2> The information about the place or the position 101 may be address information. For example, the information about the place or the position 101 may be "Tokyo and Chiyoda-ku XX-cho 1-1-1."

[0041] <Example 3> The information 101 relating to a place or a position may be information about a building, a facility, etc. For example, information such as "Tokyo Tower" may be the information 101 relating to a place or a position.

[0042] <Example 4> The information 101 relating to the location or position may be information relating to the specific location or position of an object installed in a building, facility, or the like.

[0043] For example, suppose there is space in a parking lot that can accommodate five cars. In this case, the first parking space is called A-1, the second parking space is called A-2, the third parking space is called A-3, the fourth parking space is called A-4, and the fifth parking space is called A-5. In this case, for example, information such as "A-3" may be used as information 101 related to the location or position.

[0044] Note that such an example is not limited to the case of a parking lot. For example, information about "areas, seats, stores, facilities, etc." in concert facilities, stadiums for baseball, soccer, tennis, etc., airplanes, airport lounges, railways, stations, etc. may be used as information about places or information about positions 101.

[0045] The above describes examples of the location-related information or position-related information 101. However, the method of configuring the location-related information or position-related information 101 is not limited to the above examples.

[0046] [Configuration of Terminal 150] Terminal 150 (corresponding to a receiver for visible light communication) in FIG. 6 receives modulated signal 103 transmitted from first device 100.

[0047] The light receiving unit (photoreceiver) 151 is, for example, an image sensor such as a CMOS (Complementary Metal Oxide Semiconductor) or an organic CMOS. The light receiving unit 151 receives light including a modulated signal transmitted from the first device 100 and outputs a received signal 152.

[0048] Note that the received signal 152 output from the light receiving unit 151 may be a signal containing information about an image or video captured by an image sensor, or may be an output signal from another element that performs optical-to-electrical conversion (converts light to an electrical signal). In the following description, when it is stated that the receiving device receives a modulated signal without specifically explaining the processing performed by the light receiving unit 151, this means that the receiving device performs optical-to-electrical conversion (converts light to an electrical signal) from light containing the modulated signal using the light receiving unit 151, thereby obtaining a "modulated signal for transmitting information," or an "image / video signal" and a "modulated signal for transmitting information." However, the above-mentioned method is one example of a method by which the receiving device receives a modulated signal, and the method of receiving a modulated signal is not limited to this.

[0049] Then, receiving section 153 receives received signal 152 as input, performs processes such as demodulation and error correction decoding on the modulated signal included in received signal 152 , and outputs received data 154 .

[0050] The data analysis unit 155 receives the received data 154 as input, analyzes the received data 154, and thereby estimates, for example, the location and position of the terminal 150, and outputs information 156 including at least the location and position information of the terminal 150.

[0051] The display unit 157 receives the information 156 as an input, and displays information relating to the location and position of the terminal 150 based on the location and position information of the terminal 150 included in the information 156 .

[0052] [Frame composition] FIG. 7 shows an example of a frame structure of a modulated signal transmitted by the first device 100. In FIG.

[0053] 7, the horizontal axis represents time. First device 100 transmits, for example, preamble 201, followed by control information symbol 202, location or position information symbol 203, and time information symbol 204.

[0054] Preamble 201 is a symbol used by terminal 150 receiving the modulated signal transmitted by first device 100 to perform, for example, signal detection, time synchronization, frame synchronization, and the like.

[0055] The control information symbols 202 are symbols that contain data such as the modulation signal configuration method, the error correction coding method used, and the frame configuration method.

[0056] The symbol 203 relating to location information or position information is a symbol including the information relating to location or position 101 shown in FIG.

[0057] The frame may include symbols other than symbols 201, 202, and 203. For example, as shown in FIG. 7, it may include symbol 204 relating to time information. Symbol 204 relating to time information includes, for example, information 105 relating to the time at which first device 100 transmits the modulated signal. The structure of the frame of the modulated signal transmitted by first device 100 is not limited to that shown in FIG. 7, and the symbols included in the modulated signal are not limited to the structure shown in FIG. 7. The frame may include symbols containing other data and information.

[0058] [effect] As explained in FIGS. 6 and 7, the effect when first device 100 transmits a modulated signal and terminal 150 receives the modulated signal will be explained.

[0059] Since the first device 100 transmits a modulated signal using visible light, the terminal 150 that can receive this modulated signal is not located far from the location of the first device 100. Therefore, by the terminal 150 obtaining the location and position information transmitted by the first device 100, the terminal 150 can easily obtain highly accurate position information (without performing complex signal processing).

[0060] Furthermore, if the first device 100 is installed in a location where it is difficult to receive satellite radio waves from the GPS, the terminal 150 can safely obtain highly accurate location information by receiving the modulated signal transmitted by the first device 100 even in a situation where it is difficult to receive radio waves from the GPS satellite.

[0061] (Embodiment 2) In this embodiment, a case will be described in which a plurality of first devices 100 described in the first embodiment exist.

[0062] In this embodiment, for example, as shown in Fig. 8, 1-1 device 301-1 having a configuration similar to that of 1st device 100 shown in Fig. 6 transmits a modulated signal. Terminal 302 having a configuration similar to that of terminal 150 shown in Fig. 6 receives the modulated signal transmitted by 1-1 device 301-1, and obtains, for example, information about the location and position of 1-1 and information about the time of 1-1.

[0063] Similarly, a first device 301-2 having the same configuration as the first device 100 shown in Fig. 6 transmits a modulated signal. The terminal 302 receives the modulated signal transmitted by the first device 301-2 and obtains, for example, information about the location and position of the first device 301-2 and information about the time of the first device 301-2.

[0064] 8 from the information about the location and position of 1-1 and the information about the location and position of 1-2. Furthermore, the terminal 302 can calculate the distance between the terminal 302 and the 1-1 device 301-1 based on the information about the time of 1-1 and, for example, the time when the terminal 302 received the modulated signal transmitted by the 1-1 device 301-1. Similarly, the terminal 302 can calculate the distance between the terminal 302 and the 1-2 device 301-2 based on the information about the time of 1-2 and, for example, the time when the terminal 302 received the modulated signal transmitted by the 1-2 device 301-2.

[0065] Furthermore, the terminal 302 knows the location of the 1-1 device 301-1 from the information relating to the place and location of the 1-1 device, and the terminal 302 knows the location of the 1-2 device 301-2 from the information relating to the place and location of the 1-2 device.

[0066] Furthermore, terminal 302 can determine the "triangle formed by 1-1 device 301-1, 1-2 device 301-2, and terminal 302" from the "distance between 1-1 device 301-1 and 1-2 device 301-2," "distance between 1-1 device 301-1 and terminal 302," and "distance between 1-2 device 301-2 and terminal 302."

[0067] Therefore, terminal 302 can calculate and obtain its position with high accuracy from "the position of device 1-1 301-1," "the position of device 1-2 301-2," and "the triangle formed by device 1-1 301-1, device 1-2 301-2, and terminal 302."

[0068] However, the geodetic surveying method by which the terminal 302 obtains location and position information is not limited to the above description, and any method of geodetic surveying may be used, such as triangulation, polygonal surveying, trilateration, and leveling.

[0069] As described above, in this embodiment, the terminal 302 obtains the above-mentioned information from multiple devices 301 equipped with light sources that transmit location information, thereby enabling the terminal 302 to estimate the position of the terminal 302 with high accuracy.

[0070] Furthermore, in this embodiment, as described in embodiment 1, if device 301 equipped with a light source that transmits location information is installed in a location where it is difficult to receive satellite radio waves from GPS, terminal 302 can safely obtain highly accurate location information by receiving the modulated signal transmitted by device 301 even in a situation where it is difficult to receive radio waves from the GPS satellite.

[0071] In the above example, the terminal 302 receives modulated signals transmitted by two devices 301, but the present invention can be implemented in a similar manner even when the terminal 302 receives modulated signals transmitted by more than two devices 301. The greater the number of devices 301, the more accurately the terminal 302 can calculate location information.

[0072] (Embodiment 3) FIG. 9 shows an example of the configuration of the device 400, the terminal 450, and the base station 470 (or AP (access point)) that communicates with the terminal 450 in this embodiment.

[0073] The device 400 includes, for example, a visible light source such as an LED, an illumination, a light source, or a light. Note that, hereinafter, the device 400 may also be referred to as a "first device."

[0074] In the first device 400 shown in Fig. 9, the same reference numerals are used to designate components that operate in the same manner as the first device 100 shown in Fig. 6. In addition, in the terminal 450 shown in Fig. 9, the same reference numerals are used to designate components that operate in the same manner as the terminal 150 shown in Fig. 6.

[0075] 9, transmitter 102 receives, as input, for example, location-related or position-related information 101, information 401-1 on an SSID (service set identifier) ​​that is an identifier of base station 470, and information 401-2 on an access destination. Transmitting unit 102 may also receive, as input, information 105 on time.

[0076] The transmitter 102 receives as input information about location or position 101, information about SSID 401-1, information about access destination 401-2, and / or information about time 105, generates an (optical) modulated signal 103 based on these input signals, and outputs the modulated signal 103. The modulated signal 103 is then transmitted from a light source 104, for example.

[0077] Note that examples of the information 101 relating to the location or the position have been explained in the first embodiment, and therefore will not be explained here.

[0078] Next, information 401-1 relating to the SSID and information 401-2 relating to the access destination will be described.

[0079] First, the information 401-1 relating to the SSID will be described.

[0080] SSID information 401-1 is information indicating the SSID of base station 470 in Fig. 9. Here, if it is known that the SSID notified by the optical signal is the SSID of a secure base station, first device 400 can provide terminal 450 with access to base station 470, which is a secure access destination. This allows terminal 450 in Fig. 9 to securely obtain information from base station 470.

[0081] On the other hand, the first device 400 can limit the terminals that access the base station 470 to terminals located in a space that can receive the optical signal transmitted (irradiated) by the first device 400.

[0082] Note that, when the terminal 450 receives an optical signal transmitted in a predetermined manner, the terminal 450 may determine that the notified SSID is the SSID of a secure base station. The terminal 450 may also separately perform a process for determining whether the notified SSID is secure. For example, the first device 400 may transmit an optical signal including a predetermined identifier, and the terminal 450 may determine whether the notified SSID is the SSID of a secure base station based on the received identifier. Alternatively, the terminal 450 may use the characteristics of visible light to allow the user to select a highly secure first device 400, and have the terminal 450 receive an optical signal from the first device 400 to acquire the SSID of the highly secure base station, without performing a process for determining whether the base station is secure.

[0083] Although FIG. 9 shows only base station 470, even if there are one or more base stations (or APs) other than base station 470, terminal 450 will access base station 470 using the SSID acquired from first device 400 to obtain information.

[0084] Next, the information 401-2 relating to the access destination will be described.

[0085] Information 401-2 relating to the access destination is information relating to the access destination for obtaining information after terminal 450 accesses base station 470. Note that a specific example of the operation of this embodiment will be described later.

[0086] The information 401-1 relating to the SSID and the information 401-2 relating to the access destination have been described above.

[0087] The terminal 450 receives the modulated signal 103 transmitted from the first device 400 .

[0088] The light receiving unit 151 is, for example, an image sensor such as a CMOS or an organic CMOS. The light receiving unit 151 receives light including a modulated signal transmitted from the first device 400 and outputs a received signal 152.

[0089] The receiving unit 153 receives the received signal 152 received by the light receiving unit 151 as input, performs processing such as demodulation and error correction decoding on the modulated signal included in the received signal 152 , and outputs received data 154 .

[0090] Data analysis unit 155 receives received data 154 as input and estimates, for example, the location and position of terminal 450 from received data 154. Data analysis unit 155 then outputs information 156 including at least the location and position information of terminal 450, information 451 related to the SSID, and information 452 related to the access destination.

[0091] Display unit 157 receives information 156 including location / position information of terminal 450, information 451 relating to the SSID, and information 452 relating to the access destination, and displays, for example, the location / position of terminal 450, the SSID of the communication partner accessed by wireless device 453 equipped in terminal 450, and / or the access destination (hereinafter, this display will be referred to as the "first display").

[0092] For example, after the first display, wireless device 453 receives information 451 about the SSID and information 452 about the access destination. Then, wireless device 453 connects to the other party to communicate with, for example, by using radio waves, based on information 451 about the SSID. In the case of FIG. 9, wireless device 453 connects to base station 470.

[0093] Then, based on information 452 relating to the access destination, wireless device 453 generates a modulated signal from data including information relating to the access destination, and transmits this modulated signal to base station 470 using, for example, radio waves.

[0094] In FIG. 9, base station 470, which is the communicating party of terminal 450, receives the modulated signal transmitted by radio equipment 453 included in terminal 450.

[0095] Then, base station 470 performs processes such as demodulation and error correction decoding on the received modulated signal, and outputs received data 471 including the access destination information transmitted from terminal 450. Based on this access destination information, base station 470 accesses the desired access destination via the network and obtains, for example, desired information 472 from the access destination. Then, base station 470 receives desired information 472 as input, generates a modulated signal from desired information 472, and transmits this modulated signal to terminal 450 (wireless device 453) using, for example, radio waves.

[0096] Radio equipment 453 of terminal 450 receives the modulated signal transmitted from base station 470 and performs processing such as demodulation and error correction decoding to obtain desired information 472 .

[0097] For example, the desired information 472 may be a map, a building map or floor guide, a facility map or floor guide, a parking lot map or floor guide, or information on "areas, seats, stores, and facilities" in a concert facility, stadium, airplane, airport lounge, train station, etc.

[0098] Display unit 157 receives as input information 454 including desired information 472, information 156 including at least the location and position information of terminal 450, and information 451 relating to the SSID, and after a first display, displays a map, floor guide, facility information, seat information, and store information, mapping the location of terminal 450 from desired information 472 and information 156 including at least the location and position information of terminal 450.

[0099] FIG. 10 shows a specific example of the display on the display unit 157.

[0100] The display in Figure 10 indicates "floor 3." A-1, A-2, A-3, A-4, A-21, A-22, A-23, and A-24 indicate the locations of car parking spaces, respectively. Also, a-1 and a-2 indicate the location of the elevator. Map information including the locations of these parking spaces and elevators is an example of desired information 454 (472).

[0101] 10, display unit 157 displays the current location of terminal 450 by mapping it on a map. The current location is information obtained from information 156 that includes at least the location and position information of terminal 450.

[0102] Fig. 11 shows an example of the frame structure of a modulated signal transmitted by first device 400 shown in Fig. 9. In Fig. 11, the horizontal axis represents time. In Fig. 11, symbols transmitting the same information as in Fig. 7 are assigned the same reference numerals, and their description will be omitted.

[0103] The first device 400 transmits a preamble 201, a control information symbol 202, a symbol 203 relating to location or position information, a symbol 204 relating to time information, as well as a symbol 600-1 relating to the SSID and a symbol 600-2 relating to the access destination.

[0104] Symbol 600-1 relating to the SSID is a symbol for transmitting information 401-1 relating to the SSID in Fig. 9, and symbol 600-2 relating to the access destination is a symbol for transmitting information 401-2 relating to the access destination in Fig. 9. Note that the frame in Fig. 11 may include symbols other than those shown in Fig. 11. Also, the frame configuration, including the order in which the symbols are transmitted, is not limited to the configuration in Fig. 11.

[0105] Fig. 12 shows an example of a frame configuration of a modulated signal transmitted by base station 470 shown in Fig. 9. In Fig. 12, the horizontal axis represents time.

[0106] As shown in FIG. 12, the base station 470 transmits, for example, a preamble 701, followed by a control information symbol 702 and an information symbol 703.

[0107] Preamble 701 is a symbol used by terminal 450 receiving a modulated signal transmitted by base station 470 to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, and the like.

[0108] The control information symbol 702 is a symbol containing data such as the error correction coding method used to generate the modulated signal, information about the modulation method, information about the frame structure, etc. The radio device 453 of the terminal 450 demodulates the modulated signal based on the information in the control information symbol 702.

[0109] Information symbols 703 are symbols for transmitting information. In this embodiment, information symbols 703 are symbols for transmitting desired information 472 described above.

[0110] Note that base station 470 shown in Fig. 9 may transmit a frame including symbols other than those shown in Fig. 12. For example, base station 470 may transmit a frame including a pilot symbol (reference symbol) in the middle of information symbol 703. Furthermore, the frame configuration, including the order in which symbols are transmitted, is not limited to the configuration in Fig. 12. Furthermore, in Fig. 12, multiple symbols may exist in the frequency axis direction. In other words, in Fig. 12, symbols may exist on multiple frequencies (multiple carriers).

[0111] 11 transmitted by first device 400 at regular intervals, for example, repeatedly, so that multiple terminals 450 can perform the operations described above.

[0112] FIG. 13 is a flowchart showing an example of the processing performed by the "first device 400," "terminal 450," and "base station 470" shown in FIG. 9 described above.

[0113] First, first device 400 transmits a modulated signal with the frame configuration shown in FIG. 11 (ST801).

[0114] Terminal 450 then receives the modulated signal transmitted by first device 400 and estimates the location and position of terminal 450 (ST802).

[0115] At the same time, terminal 450 receives the modulated signal transmitted by first device 400 and ascertains the SSID of base station 470 that terminal 450 will access (ST803).

[0116] Then, terminal 450 transmits a modulated signal including data including information 452 relating to an access destination for obtaining information such as a map to base station 470, for example, using radio waves (ST804).

[0117] Base station 470 receives the modulated signal transmitted by terminal 450, obtains information about the access destination, accesses the desired access destination via the network, and obtains desired information (information to be transmitted to terminal 450) such as a map (ST805).

[0118] Then, base station 470 transmits a modulated signal including the desired information such as the acquired map to terminal 450 using, for example, radio waves (ST806).

[0119] Terminal 450 receives the modulated signal transmitted by base station 470 and obtains information such as a map. Terminal 450 then displays the information as shown in Fig. 10 based on the information such as the map and the location and position information of terminal 450 that has already been obtained.

[0120] Next, an example of operation when a plurality of first devices 400 and a base station 470 are installed in the location shown in FIG. 10 will be described.

[0121] Figure 14 shows a map of the same location as Figure 10. That is, Figure 14 is a map of the "third floor" as explained in Figure 10. In Figure 14, A-1, A-2, A-3, A-4, A-21, A-22, A-23, and A-24 indicate car parking spaces, and a-1 and a-2 indicate elevators.

[0122] 9 is installed at the position of "○" 901-1 in FIG. 14. Hereinafter, the first device having the same configuration as first device 400 installed at the position 901-1 will be referred to as "1-1 device 400." 1-1 device 400 has information "A-1" as information relating to the location or position, and transmits the information "A-1."

[0123] A first device having a configuration similar to that of first device 400 in Fig. 9 is installed at the position of "circle" 901-2 in Fig. 14. Hereinafter, the first device having a configuration similar to that of first device 400 installed at position 901-2 will be referred to as "1-2 device 400." 1-2 device 400 has information "A-2" as information related to the location or position, and transmits the information "A-2."

[0124] A first device having a configuration similar to that of first device 400 in Fig. 9 is installed at the position of "circle" 901-3 in Fig. 14. Hereinafter, the first device having a configuration similar to that of first device 400 installed at position 901-3 will be referred to as "1-3 device 400." 1-3 device 400 has information "A-3" as information related to the location or position, and transmits the information "A-3."

[0125] A first device having a configuration similar to that of the first device 400 in Fig. 9 is installed at the position of "circle" 901-4 in Fig. 14. Hereinafter, the first device having a configuration similar to that of the first device 400 installed at the position 901-4 will be referred to as "1-4 device 400." 1-4 device 400 has information "A-4" as information related to the location or position, and transmits the information "A-4."

[0126] A first device having a configuration similar to that of first device 400 in Fig. 9 is installed at the position of "circle" 901-21 in Fig. 14. Hereinafter, the first device having a configuration similar to that of first device 400 installed at position 901-21 will be referred to as "1-21 device 400." 1-21 device 400 has information "A-21" as information related to the location or position, and transmits the information "A-21."

[0127] A first device having a configuration similar to that of the first device 400 in Fig. 9 is installed at the position of "circle" 901-22 in Fig. 14. Hereinafter, the first device having a configuration similar to that of the first device 400 installed at the position 901-22 will be referred to as "device 1-22 400". Device 1-22 400 has information "A-22" as information related to the location or position, and transmits the information "A-22".

[0128] A first device having a configuration similar to that of first device 400 in Fig. 9 is installed at the position of "circle" 901-23 in Fig. 14. Hereinafter, the first device having a configuration similar to that of first device 400 installed at position 901-23 will be referred to as "device 1-23 400." Device 1-23 400 has information "A-23" as information related to the location or position, and transmits the information "A-23."

[0129] A first device having a configuration similar to that of first device 400 in Fig. 9 is installed at the position of "circle" 901-24 in Fig. 14. Hereinafter, the first device having a configuration similar to that of first device 400 installed at position 901-24 will be referred to as "1-24th device 400." 1-24th device 400 has information "A-24" as information related to the location or position, and transmits the information "A-24."

[0130] 14, a base station (or AP) having a configuration similar to that of base station 470 in FIG. 9 is installed at the position indicated by "◎" 902. Hereinafter, a base station (or AP) having a configuration similar to that of base station 470 in FIG. 9 will be simply referred to as "base station 470." Here, the SSID of base station 470 installed at the position 902 is assumed to be "abcdef."

[0131] When a terminal 450 located near the position shown on the map in FIG. 14 wishes to perform wireless communication, it simply needs to access a base station 470 installed at a position 902 in FIG.

[0132] Therefore, the "1-1st device 400" installed at 901-1 in FIG. 14 transmits "abcdef" as information relating to the SSID (see 401-1 in FIG. 9).

[0133] Similarly, the "1-2nd device 400" installed at 901-2 in FIG. 14 transmits "abcdef" as information relating to the SSID (see 401-1 in FIG. 9).

[0134] The "first-third device 400" installed at 901-3 in FIG. 14 transmits "abcdef" as information related to the SSID (see 401-1 in FIG. 9).

[0135] The "first to fourth device 400" installed at 901-4 in FIG. 14 transmits "abcdef" as information relating to the SSID (see 401-1 in FIG. 9).

[0136] The "1-21st device 400" installed at 901-21 in FIG. 14 transmits "abcdef" as information related to the SSID (see 401-1 in FIG. 9).

[0137] The "1-22nd device 400" installed at 901-22 in FIG. 14 transmits "abcdef" as information related to the SSID (see 401-1 in FIG. 9).

[0138] The "1-23rd device 400" installed at 901-23 in FIG. 14 transmits "abcdef" as information related to the SSID (see 401-1 in FIG. 9).

[0139] The "1-24th device 400" installed at 901-24 in FIG. 14 transmits "abcdef" as information related to the SSID (see 401-1 in FIG. 9).

[0140] A specific example of the operation will be described below.

[0141] Assume that a terminal (hereinafter simply referred to as "terminal 450") having the same configuration as terminal 450 in FIG. 9 is located at position 903-1 in FIG. 14. In this case, terminal 450 receives a modulated signal transmitted by "1-4 device 400" located at position 901-4 in FIG. 14, and obtains location information "A-4." Terminal 450 also receives a modulated signal transmitted by "1-4 device 400" located at position 901-4 in FIG. 14, and obtains SSID information "abcdef." As a result, terminal 450 accesses base station 470 located at 902 in FIG. 14. Terminal 450 also obtains information such as a map from base station 470 located at 902 in FIG. 14. Then, terminal 450 displays the map information and location information (see, for example, FIG. 10. However, FIG. 10 is merely an example of a display).

[0142] Similarly, it is assumed that a terminal (hereinafter simply referred to as "terminal 450") having the same configuration as terminal 450 in FIG. 9 is present at position 903-2 in FIG. 14. In this case, terminal 450 receives a modulated signal transmitted by "first 22 device 400" located at position 901-22 in FIG. 14, and obtains location information of "A-22." Terminal 450 also receives a modulated signal transmitted by "first-fourth device 400" located at position 901-22 in FIG. 14, and obtains SSID information of "abcdef." As a result, terminal 450 accesses base station 470 located at 902 in FIG. 14. Terminal 450 also obtains information such as a map from base station 470 located at 902 in FIG. 14. Then, terminal 450 displays the map information and location information (see, for example, FIG. 10. However, FIG. 10 is merely an example of a display).

[0143] 14 (periphery information) and location information in a storage unit (not shown) provided in terminal 450, and the user of terminal 450 may retrieve the information recorded in the storage unit when necessary. This allows the user to more conveniently utilize the map (periphery information) and location information.

[0144] As described above, since the first device 400 transmits a modulated signal using visible light, the terminal 450 that can receive this modulated signal is limited to a range within which the optical signal can be received from the position of the first device 400. Therefore, by receiving the location and position information transmitted by the first device 400, the terminal 450 can easily obtain highly accurate position information (without complex signal processing).

[0145] Furthermore, if the first device 400 is installed in a location where it is difficult to receive satellite radio waves from the GPS, the terminal 450 can safely obtain highly accurate location information by receiving the modulated signal transmitted by the first device 400 even in a situation where it is difficult to receive radio waves from the GPS satellite.

[0146] Furthermore, the terminal 450 can securely obtain information by connecting to the base station (or AP) 470 and obtaining the information based on the SSID information transmitted from the first device 400. This is because, when the terminal 450 obtains information from a modulated signal of visible light, the user can easily recognize the first device 400 that transmitted the modulated signal by visual inspection, etc., since the information is visible light, and it is easy to determine whether the source of the information is secure. In contrast, for example, when the SSID is obtained from a modulated signal of radio waves transmitted by a wireless LAN, it is difficult for the user to identify the device that transmitted the radio waves. Therefore, in terms of ensuring the security of information, visible light communication is more suitable for obtaining an SSID than wireless LAN communication.

[0147] It should be noted that a plurality of signals may further be input to radio device 453 of terminal 450 in Fig. 9. For example, a control signal for controlling radio device 453 and information to be transmitted to base station 470 may be input to radio device 453. In this case, an example of an operation in which radio device 453 starts communication based on the control signal is conceivable. As described above, in this embodiment, the configuration of the first device is not limited to the configuration of first device 400 in Fig. 9, the configuration of the terminal is not limited to the configuration of terminal 450 in Fig. 9, and the connection destination and configuration of base station 470 are not limited to those shown in Fig. 9.

[0148] 9 illustrates a case where one base station 470 is installed, but there may be multiple (secure) base stations (or APs) accessible to terminal 450. In this case, the symbol relating to the SSID transmitted by first device 400 in FIG. 9 may include information indicating the SSIDs of each of these multiple base stations (or APs). In this case, a list of SSIDs of multiple base stations and / or a list of multiple access destinations is displayed on display unit 157 of terminal 450 in FIG. 9 as a display of access destinations (the "first display" described above). Terminal 450 in FIG. 9 may then select one or more base stations to actually connect to wirelessly based on the information on the SSIDs of the multiple base stations (or APs) (i.e., it may connect to multiple base stations simultaneously).

[0149] For example, assume that three base stations 470 are deployed. Here, the three base stations 470 are referred to as base station #A, base station #B, and base station #C, respectively. Also, the SSID of base station #A is "abcdef," the SSID of base station #B is "ghijk," and the SSID of base station #C is "pqrstu." In this case, SSID-related symbol 600-1 in the frame configuration shown in FIG. 11 of the modulated signal transmitted by first device 400 includes information that "the SSID of base station #A is 'abcdef'," "the SSID of base station #B is 'ghijk'," and "the SSID of base station #C is 'pqrstu'." Then, terminal 450 in FIG. 9 receives SSID-related symbol 600-1 and selects one or more base stations 470 to actually connect to wirelessly based on the information that "the SSID of base station #A is 'abcdef'," "the SSID of base station #B is 'ghijk'," and "the SSID of base station #C is 'pqrstu'."

[0150] (Fourth embodiment) FIG. 15 is a diagram showing an example of the configuration of a communication system according to this embodiment.

[0151] The communication system in FIG. 15 includes, for example, device 1000, terminal 1050, and base station (or AP) 470 that communicates with terminal 1050.

[0152] The device 1000 includes, for example, a visible light source such as an LED, an illumination, a light source, or a light (hereinafter referred to as a light source 104). Note that, hereinafter, the device 1000 may also be referred to as a "second device" in this embodiment.

[0153] In the second device 1000 shown in Fig. 15, components that operate in the same manner as the first device 100 shown in Fig. 6 are assigned the same numbers. In the terminal 1050 shown in Fig. 15, components that operate in the same manner as the terminal 150 shown in Fig. 6 are assigned the same numbers. In addition, it is assumed that communication between the wireless device 453 of the terminal 1050 shown in Fig. 15 and the base station 470 uses, for example, radio waves.

[0154] 15, transmitter 102 receives information 1001-1 related to the SSID, information 1001-2 related to the encryption key, and data 1002 as input, generates (optical) modulated signal 103 based on these input signals, and outputs modulated signal 103. Modulated signal 103 is then transmitted from light source 104, for example.

[0155] Next, the information 1001-1 about the SSID and the information 1001-2 about the encryption key will be described.

[0156] First, the information 1001-1 relating to the SSID will be described.

[0157] Information 1001-1 related to SSID is information indicating the SSID of base station 470 in Fig. 15. For example, base station 470 transmits a modulated signal to terminal 1050 via radio waves, and receives a modulated signal from terminal 1050 via radio waves. In other words, second device 1000 can provide terminal 1050 with access to base station 470, which is a secure access destination. This allows terminal 1050 in Fig. 15 to securely obtain information from base station 470.

[0158] On the other hand, the second device 1000 can limit the terminals that access the base station 470 to terminals located in a space that can receive the optical signal transmitted (irradiated) by the second device 1000.

[0159] When terminal 1050 receives an optical signal transmitted in a predetermined manner, terminal 1050 may determine that the notified SSID is the SSID of a secure base station. Terminal 1050 may also perform a separate process to determine whether the notified SSID is secure. For example, second device 1000 may transmit an optical signal including a predetermined identifier, and terminal 1050 may determine whether the notified SSID is the SSID of a secure base station based on the received identifier.

[0160] Although FIG. 15 shows only base station 470, even if there is a base station (or AP) other than base station 470, terminal 1050 will access base station 470 using the SSID acquired from second device 1000 to obtain information.

[0161] Next, the information 1001-2 relating to the encryption key will be described.

[0162] The information 1001-2 relating to the encryption key is information relating to the encryption key that is required for the terminal 1050 to communicate with the base station 470. By obtaining the information 1001-2 relating to the encryption key from the second device 1000, the terminal 1050 becomes able to perform encrypted communication with the base station 470.

[0163] The information 1001-1 relating to the SSID and the information 1001-2 relating to the encryption key have been described above.

[0164] Terminal 1050 in Fig. 15 receives the modulated signal transmitted by second device 1000. Note that in terminal 1050 in Fig. 15, components that operate in the same manner as terminal 150 in Fig. 6 and terminal 450 in Fig. 9 are assigned the same numbers.

[0165] The light receiving unit 151 included in the terminal 1050 is, for example, an image sensor such as a CMOS or an organic CMOS. The light receiving unit 151 receives light including a modulated signal transmitted from the second device 1000 and outputs a received signal 152.

[0166] The receiving unit 153 receives the received signal 152 received by the light receiving unit 151 as input, performs processing such as demodulation and error correction decoding on the modulated signal included in the received signal 152 , and outputs received data 154 .

[0167] The data analyzer 155 receives the received data 154 as input and outputs, for example, information 1051 about the SSID of the base station to be connected to and information 1052 about the encryption key for communicating with the base station to be connected to, from the received data 154. For example, encryption methods for a wireless LAN (Local Area Network) include WEP (Wired Equivalent Privacy), WPA (Wi-Fi (registered trademark) Protected Access), and WPA2 (Wi-Fi Protected Access 2) (PSK (Pre-Shared Key) mode, EAP (Extended Authentication Protocol) mode). However, the encryption method is not limited to these.

[0168] Display unit 157 receives SSID information 1051 and encryption key information 1052 as input, and displays, for example, the SSID and encryption key of the communication partner accessed by wireless device 453 provided in terminal 1050 (this display is referred to as the "first display" in this embodiment).

[0169] For example, after the first display, wireless device 453 receives SSID information 1051 and encryption key information 1052 as input and establishes a connection with base station 470 (for example, the connection is assumed to be via radio waves). At this time, when base station 470 communicates with wireless device 453 included in terminal 1050, it also transmits a modulated signal using, for example, radio waves.

[0170] Thereafter, wireless device 453 receives data 1053 and control signal 1054 as input, modulates data 1053 in accordance with the control indicated by control signal 1054, and transmits the modulated signal via radio waves.

[0171] Then, for example, base station 470 transmits data to the network (471) and receives data from the network (472). After that, for example, base station 470 transmits a modulated signal to terminal 1050 by radio waves.

[0172] The wireless device 453 included in the terminal 1050 performs processes such as demodulation and error correction decoding on the modulated signal received via radio waves, and acquires received data 1056. The display unit 157 displays based on the received data 1056.

[0173] Fig. 16 shows an example of a frame structure of a modulated signal transmitted by second device 1000 shown in Fig. 15. In Fig. 16, the horizontal axis represents time. In Fig. 16, the same symbols as in Fig. 7 and Fig. 11 are assigned the same numbers, and their explanation will be omitted.

[0174] The symbol 600-1 relating to the SSID is a symbol for transmitting information 1001-1 relating to the SSID in Fig. 15, and the symbol 1101 relating to the encryption key is a symbol for transmitting information 1001-2 relating to the encryption key in Fig. 15. The data symbol 1102 is a symbol for transmitting the data 1002 in Fig. 15.

[0175] The second device 1000 transmits a preamble 201, a control information symbol 202, a symbol 600-1 related to the SSID, a symbol 1101 related to the encryption key, and a data symbol 1102. The second device 1000 may transmit a frame including symbols other than those shown in Fig. 16. The frame configuration, including the order in which the symbols are transmitted, is not limited to that shown in Fig. 16.

[0176] Fig. 17 shows an example of a frame structure of a modulated signal transmitted by radio equipment 453 included in terminal 1050 in Fig. 15. In Fig. 17, the horizontal axis represents time.

[0177] As shown in FIG. 17, radio equipment 453 included in terminal 1050 transmits, for example, preamble 1201, and then transmits control information symbol 1202 and information symbol 1203.

[0178] Preamble 1201 is a symbol used by base station 470, which receives the modulated signal transmitted by radio equipment 453 of terminal 1050, to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, and the like.

[0179] The control information symbol 1202 is a symbol that includes data such as the error correction coding method used to generate the modulated signal, information about the modulation method, information about the frame structure, information about the transmission method, etc. The base station 470 performs demodulation of the modulated signal based on the information included in the control information symbol 1202.

[0180] Information symbols 1203 are symbols used by radio equipment 453 of terminal 1050 to transmit data.

[0181] Note that radio equipment 453 of terminal 1050 may transmit a frame including symbols other than those shown in Fig. 17. For example, radio equipment 453 may transmit a frame including a pilot symbol (reference symbol) in the middle of information symbols 1203. Also, the frame configuration, including the order in which symbols are transmitted, is not limited to that of Fig. 17. Also, in Fig. 17, multiple symbols may exist in the frequency axis direction. That is, in Fig. 17, symbols may exist at multiple frequencies (multiple carriers). Also, in the third embodiment, radio equipment 453 included in terminal 450 of Fig. 9 may use the frame configuration of Fig. 17 when transmitting a modulated signal.

[0182] The frame structure of a modulated signal transmitted by base station 470 in this embodiment is the same as the frame structure shown in Fig. 12 described in Embodiment 3. That is, as shown in Fig. 12, base station 470 transmits, for example, preamble 701, and then transmits control information symbol 702 and information symbol 703.

[0183] Preamble 701 is a symbol used by radio equipment 453 of terminal 1050 that receives a modulated signal transmitted by base station 470 to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, and the like.

[0184] The control information symbol 702 is a symbol containing data such as the error correction coding method used to generate the modulated signal, information about the modulation method, information about the frame structure, information about the transmission method, etc. The wireless device 453 of the terminal 1050 demodulates the modulated signal based on the information in the control information symbol 702.

[0185] Information symbols 703 are symbols used by base station 470 to transmit data.

[0186] Note that base station 470 shown in Fig. 15 may transmit a frame including symbols other than those shown in Fig. 12. For example, base station 470 may transmit a frame including a pilot symbol (reference symbol) in the middle of information symbol 703. Furthermore, the frame configuration, including the order in which symbols are transmitted, is not limited to the configuration in Fig. 12. Furthermore, in Fig. 12, multiple symbols may exist in the frequency axis direction. That is, in Fig. 12, symbols may exist on multiple frequencies (multiple carriers).

[0187] 16 transmitted by second device 1000 at regular intervals, for example, repeatedly, so that multiple terminals 1050 can perform the operations described above.

[0188] FIG. 18 is a flowchart showing an example of processing performed by the "second device 1000," the "terminal 1050," and the "base station 470" shown in FIG.

[0189] First, second equipment 1000 transmits a modulated signal with the frame configuration shown in FIG. 16 (ST1301).

[0190] Terminal 1050 then receives the modulated signal transmitted by second device 1000 and acquires the SSID of base station 470 that terminal 1050 will access (ST1302).

[0191] At the same time, terminal 1050 acquires an encryption key to be used for communication with base station 470 that terminal 1050 accesses (ST1303).

[0192] Terminal 1050 then establishes a connection with base station 470 via radio waves (ST1304). Terminal 1050 receives a response from base station 470, thereby completing the connection with base station 470 (ST1305).

[0193] Terminal 1050 then transmits connection destination information to base station 470 using radio waves (ST1306).

[0194] Base station 470 obtains information to be transmitted to terminal 1050 from the network (ST1307).

[0195] Then, base station 470 transmits the obtained information to terminal 1050 using radio waves, and terminal 1050 receives the information (ST1308). Terminal 1050 obtains necessary information from the network via base station 470, for example, when necessary.

[0196] As described above, based on the SSID information and encryption key information transmitted from the second device 1000, the terminal 1050 connects to the base station 470 and acquires the information, thereby enabling the terminal 1050 to securely obtain the information via the base station 470, whose security is guaranteed. This is because, when the terminal 1050 acquires the information from a modulated signal of visible light, it is easy for the user to determine whether the source of the information is secure because it is visible light. In contrast, for example, when the SSID is acquired from a modulated signal of radio waves transmitted by a wireless LAN, it is difficult for the user to identify the device that transmitted the radio waves. Therefore, in terms of ensuring the security of the information, visible light communication is more suitable for acquiring the SSID than wireless LAN communication.

[0197] In the present embodiment, the case where second device 1000 transmits encryption key information has been described. However, for example, if base station 470 is not performing encrypted communication using an encryption key, second device 1000 may transmit only information related to the SSID without transmitting encryption key information. In this case, the same implementation can be achieved by simply deleting the configuration related to the encryption key from the configuration described above.

[0198] Furthermore, the configuration of the second device is not limited to the configuration of the second device 1000 shown in FIG. 15, the configuration of the terminal is not limited to the configuration of the terminal 1050 shown in FIG. 15, and the connection destination and configuration of the base station are not limited to the connection destination and configuration of the base station 470 shown in FIG. 15.

[0199] 15 illustrates a case where one base station 470 is installed, but there may be multiple (secure) base stations (or APs) accessible to the terminal 1050. These multiple base stations and the terminal 1050 transmit and receive modulated signals using radio waves. In this case, the symbol related to the SSID transmitted by the second device 1000 in FIG. 15 may include information on the SSID of each of the multiple base stations (or APs). In this case, the display unit 157 of the terminal 1050 in FIG. 15 displays a list of SSIDs of the multiple base stations and / or a list of multiple access destinations as an indication of the access destinations. In addition, the symbol related to the encryption key transmitted by the second device 1000 in FIG. 15 may include information on the encryption key used to connect to each of the multiple base stations (or APs). The terminal 1050 in FIG. 15 may select one or more base stations to actually connect to wirelessly (for example, by radio waves) based on the SSID information and encryption key information of the multiple base stations (i.e., may connect to multiple base stations simultaneously).

[0200] For example, suppose three base stations 470 are deployed. Here, the three base stations 470 are called base station #A, base station #B, and base station #C, respectively. Also, let the SSID of base station #A be "abcdef," the SSID of base station #B be "ghijk," and the SSID of base station #C be "pqrstu." Also, let the encryption key for connecting to base station #A be "123," the encryption key for connecting to base station #B be "456," and the encryption key for connecting to base station #C be "789."

[0201] In this case, symbol 600-1 relating to SSID in the frame configuration of Fig. 16 of the modulated signal transmitted by second device 1000 includes information that "the SSID of base station #A is 'abcdef'," "the SSID of base station #B is 'ghijk'," and "the SSID of base station #C is 'pqrstu'." Also, symbol 1101 relating to encryption key in the frame configuration of Fig. 16 includes information that "the encryption key for connecting with base station #A is '123'," "the encryption key for connecting with base station #B is '456'," and "the encryption key for connecting with base station #C is '789'."

[0202] Then, terminal 1050 in FIG. 15 receives symbol 600-1 related to the SSID and obtains information such as "the SSID of base station #A is 'abcdef'," "the SSID of base station #B is 'ghijk'," and "the SSID of base station #C is 'pqrstu'." Terminal 1050 also receives symbol 1101 related to the encryption key and obtains information such as "the encryption key for connecting to base station #A is '123'," "the encryption key for connecting to base station #B is '456'," and "the encryption key for connecting to base station #C is '789'." Then, based on this information, terminal 1050 selects one or more base stations to actually connect to wirelessly (for example, by radio waves) and connects to them.

[0203] Furthermore, by using a light source such as an LED as in the present embodiment to set the base station 470 to be accessed by the terminal 1050, a special setting mode for performing a procedure for connecting the terminal 1050 and the base station 470 for wireless communication is not required for the modulated signal for wireless communication transmitted by the terminal 1050. Furthermore, a special setting mode for performing a procedure for connecting the terminal 1050 and the base station 470 for wireless communication is not required for the modulated signal transmitted by the base station 470. Therefore, in the present embodiment, it is possible to improve the data transmission efficiency of wireless communication.

[0204] Furthermore, as described above, the encryption key may be an encryption key for the SSID of a wireless LAN, or may be an encryption key for restricting the connection type, service type, network connection range, etc. In other words, it is sufficient if an encryption key is introduced for some kind of restriction.

[0205] (Embodiment 5) FIG. 19 is a diagram showing an example of the configuration of a communication system according to this embodiment.

[0206] The communication system of FIG. 19 includes, for example, devices 1400A and 1400B, a terminal 1050, and a base station (or AP) 470 that communicates with terminal 1050.

[0207] The devices 1400A and 1400B are equipped with, for example, a visible light source such as an LED, illumination, a light source, or a light (hereinafter referred to as light sources 1406-1 and 1406-2). Note that, hereinafter, the device 1400A is referred to as a "third device" in this embodiment, and the device 1400B is referred to as a "fourth device" in this embodiment.

[0208] In terminal 1050 shown in Fig. 19, components that operate in the same manner as terminal 150 shown in Fig. 1 or terminal 1050 shown in Fig. 15 are assigned the same numbers. In addition, in base station (or AP) 470 shown in Fig. 19, components that operate in the same manner as base station 470 shown in Fig. 9 are assigned the same numbers as in Fig. 9. In addition, it is assumed that communication between wireless device 453 of terminal 1050 shown in Fig. 19 and base station 470 uses, for example, radio waves.

[0209] 19, a transmitter 1404-1 receives SSID-related information 1401-1 and data 1402-1 as input, generates an (optical) modulated signal 1405-1 based on these input signals, and outputs the modulated signal 1405-1. The modulated signal 1405-1 is then transmitted from, for example, a light source 1406-1.

[0210] 19, a transmitter 1404-2 receives information 1403-2 related to the encryption key and data 1402-2 as input, generates an (optical) modulated signal 1405-2 based on these input signals, and outputs the modulated signal 1405-2. The modulated signal 1405-2 is then transmitted from, for example, a light source 1406-2.

[0211] Next, the information 1401-1 relating to the SSID and the information 1403-2 relating to the encryption key will be described.

[0212] First, the information 1401-1 relating to the SSID will be described.

[0213] Information 1401-1 related to SSID is information indicating the SSID of base station 470 in Fig. 19. In other words, third device 1400A can provide terminal 1050 with access to base station 470, which is a secure access destination via radio waves. This allows terminal 1050 in Fig. 19 to securely obtain information from base station 470.

[0214] When terminal 1050 receives an optical signal transmitted in a predetermined manner, terminal 1050 may determine that the notified SSID is the SSID of a secure base station. Terminal 1050 may also perform a separate process to determine whether the notified SSID is secure. For example, third device 1400A may transmit an optical signal including a predetermined identifier, and terminal 1050 may determine whether the notified SSID is the SSID of a secure base station based on the received identifier.

[0215] Although FIG. 19 shows only base station 470, even if there is a base station (or AP) other than base station 470, terminal 1050 will access base station 470 and obtain information using the SSID obtained from third device 1400A and the encryption key obtained from fourth device 1400B.

[0216] Next, the information 1403-2 relating to the encryption key will be described.

[0217] The information 1403-2 relating to the encryption key is information relating to the encryption key that is required for the terminal 1050 to communicate by radio waves with the base station 470. By obtaining the information 1403-2 relating to the encryption key from the fourth device 1400B, the terminal 1050 becomes able to perform encrypted communication with the base station 470.

[0218] The information 1401-1 relating to the SSID and the information 1403-2 relating to the encryption key have been described above.

[0219] Terminal 1050 in FIG. 19 receives the modulated signal transmitted by third device 1400A.

[0220] The light receiving unit 151 included in the terminal 1050 is, for example, an image sensor such as a CMOS or an organic CMOS. The light receiving unit 151 receives light including a modulated signal transmitted from the third device 1400A and outputs a received signal 152.

[0221] The receiving unit 153 receives the received signal 152 received by the light receiving unit 151 as input, performs processing such as demodulation and error correction decoding on the modulated signal included in the received signal 152 , and outputs received data 154 .

[0222] Data analysis unit 155 receives received data 154 and outputs, for example, SSID information 1051 of the base station to which the wireless device 453 will connect from the received data. Wireless device 453 obtains, from SSID information 1051, information on the SSID of base station 470 to which wireless device 453 will connect via radio waves.

[0223] Terminal 1050 in FIG. 19 receives the modulated signal transmitted by fourth device 1400B.

[0224] The light receiving unit 151 included in the terminal 1050 is, for example, an image sensor such as a CMOS or an organic CMOS. The light receiving unit 151 receives light including a modulated signal transmitted from the fourth device 1400B and outputs a received signal 152.

[0225] The receiving unit 153 receives the received signal 152 received by the light receiving unit 151 as input, performs processing such as demodulation and error correction decoding on the modulated signal included in the received signal 152 , and outputs received data 154 .

[0226] The data analysis unit 155 receives the received data 154 as input and outputs, for example, encryption key information 1052 for communicating with a base station to which the connection is to be made. For example, in a wireless LAN (Local Area Network), encryption methods include WEP (Wired Equivalent Privacy), WPA (Wi-Fi Protected Access), and WPA2 (Wi-Fi Protected Access 2) (PSK (Pre-Shared Key) mode, EAP (Extended Authentication Protocol) mode). However, the encryption method is not limited to this.

[0227] The wireless device 453 included in the terminal 1050 obtains encryption key information of the base station 470 to which the wireless device 453 is connected from encryption key information 1052 for communicating with the base station to which it is connected (for example, via radio waves).

[0228] Display unit 157 receives SSID information 1051 and encryption key information 1052 as input, and displays, for example, the SSID and encryption key of the communication partner accessed by wireless device 453 provided in terminal 1050 (this display is referred to as the "first display" in this embodiment).

[0229] For example, after the first display, wireless device 453 receives SSID information 1051 and encryption key information 1052 as input and establishes a connection via radio waves with base station 470. At this time, when base station 470 communicates with wireless device 453 included in terminal 1050, it also transmits a modulated signal using, for example, radio waves.

[0230] Thereafter, wireless device 453 receives data 1053 and control signal 1054 as input, modulates data 1053 in accordance with the control indicated by control signal 1054, and transmits the modulated signal via radio waves.

[0231] Then, for example, base station 470 transmits data to the network (471) and receives data from the network (472). After that, for example, base station 470 transmits a modulated signal to terminal 1050 by radio waves.

[0232] The wireless device 453 included in the terminal 1050 performs processes such as demodulation and error correction decoding on the modulated signal received via radio waves, and acquires received data 1056. The display unit 157 displays based on the received data 1056.

[0233] Fig. 20 shows an example of a frame configuration of a modulated signal transmitted by the third device 1400A shown in Fig. 19. In Fig. 20, the horizontal axis represents time. Furthermore, in Fig. 20, the same symbols as in Figs. 2, 11, and 16 are assigned the same reference numerals, and descriptions thereof will be omitted.

[0234] The symbol 600-1 relating to the SSID is a symbol for transmitting information 1401-1 relating to the SSID in Fig. 19. The data symbol 1102 is a symbol for transmitting data 1402-1.

[0235] The third device 1400A transmits a preamble 201, a control information symbol 202, a symbol 600-1 related to the SSID, and a data symbol 1102. The third device 1400A may transmit a frame including symbols other than those shown in Fig. 20. The frame configuration, including the order in which the symbols are transmitted, is not limited to that shown in Fig. 20.

[0236] Fig. 21 shows an example of a frame configuration of a modulated signal transmitted by fourth device 1400B in Fig. 19. In Fig. 21, the horizontal axis represents time. Furthermore, in Fig. 21, the same symbols as in Fig. 7 and Fig. 16 are assigned the same reference numerals, and explanations thereof will be omitted.

[0237] The symbol 1101 relating to the encryption key is a symbol for transmitting information 1403-2 relating to the encryption key in Fig. 19. The data symbol 1102 is a symbol for transmitting data 1402-2.

[0238] Fourth device 1400B transmits preamble 201, control information symbol 202, encryption key related symbol 1101, and data symbol 1102. Note that fourth device 1400B in Fig. 19 may transmit a frame including symbols other than those shown in Fig. 21. Also, the frame configuration, including the order in which the symbols are transmitted, is not limited to that shown in Fig. 21.

[0239] The frame structure of the modulated signal transmitted by radio equipment 453 in this embodiment is the same as the frame structure shown in Fig. 17 described in embodiment 4. That is, as shown in Fig. 17, radio equipment 453 included in terminal 1050 transmits, for example, preamble 1201, and then transmits control information symbol 1202 and information symbol 1203.

[0240] The preamble 1201 is a symbol used by the base station (or AP) 470 that receives the modulated signal transmitted by the wireless device 453 of the terminal 1050 in FIG. 19 to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, etc.

[0241] The control information symbols 1202 are symbols that include data such as the error correction coding method used to generate the modulated signal, information about the modulation method, information about the frame structure, information about the transmission method, etc. The base station 470 performs demodulation of the modulated signal based on the information included in the control information symbols 1202.

[0242] Information symbols 1203 are symbols used by radio equipment 453 of terminal 1050 to transmit data.

[0243] Note that radio equipment 453 of terminal 1050 shown in Fig. 19 may transmit a frame including symbols other than those shown in Fig. 17. For example, radio equipment 453 may transmit a frame including a pilot symbol (reference symbol) in the middle of information symbol 1203. Also, the frame configuration, including the order in which symbols are transmitted, is not limited to that shown in Fig. 17. Also, in Fig. 17, multiple symbols may exist in the frequency axis direction. That is, in Fig. 17, symbols may exist at multiple frequencies (multiple carriers).

[0244] The frame structure of a modulated signal transmitted by base station 470 in this embodiment is the same as the frame structure shown in Fig. 12 described in Embodiment 3. That is, as shown in Fig. 12, base station 470 transmits, for example, preamble 701, and then transmits control information symbol 702 and information symbol 703.

[0245] Preamble 701 is a symbol used by radio equipment 453 of terminal 1050 in FIG. 19, which receives the modulated signal transmitted by base station 470, to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, and frequency offset estimation.

[0246] The control information symbol 702 is a symbol containing data such as the error correction coding method used to generate the modulated signal, information about the modulation method, information about the frame structure, information about the transmission method, etc. The wireless device 453 of the terminal 1050 in Fig. 19 demodulates the modulated signal based on the information in the control information symbol 702.

[0247] Information symbols 703 are symbols used by base station 470 in FIG. 19 to transmit data.

[0248] Note that base station 470 shown in Fig. 19 may transmit a frame including symbols other than those shown in Fig. 12. For example, base station 470 may transmit a frame including a pilot symbol (reference symbol) in the middle of information symbol 703. Also, the frame configuration, including the order in which symbols are transmitted, is not limited to the configuration in Fig. 12. Also, in Fig. 12, multiple symbols may exist in the frequency axis direction. That is, in Fig. 12, symbols may exist on multiple frequencies (multiple carriers).

[0249] Also, for example, a method can be considered in which the modulated signal having the frame structure of FIG. 20 transmitted by the third device 1400A is transmitted at regular timing, for example, repeatedly. This allows multiple terminals 1050 to perform the operations described above. Similarly, a method can be considered in which the modulated signal having the frame structure of FIG. 21 is transmitted by the fourth device 1400B is transmitted at regular timing, for example, repeatedly. This allows multiple terminals 1050 to perform the operations described above.

[0250] Fig. 22 is a flowchart showing a first example of processing performed by the "third device 1400A," "fourth device 1400B," "terminal 1050," and "base station 470" shown in Fig. 19. In Fig. 22, the same numbers are used for components that operate in the same way as in Fig. 18.

[0251] First, third device 1400A transmits a modulated signal with the frame configuration shown in FIG. 20 (ST1701).

[0252] Terminal 1050 then receives the modulated signal transmitted by third device 1400A and acquires the SSID of base station 470 that terminal 1050 will access (ST1702).

[0253] Next, fourth device 1400B transmits a modulated signal with the frame configuration shown in FIG. 21 (ST1703).

[0254] Terminal 1050 then receives the modulated signal transmitted by fourth device 1400B, and acquires the encryption key used for communication with base station 470 accessed by terminal 1050 (ST1704).

[0255] Terminal 1050 then establishes a connection with base station 470 via radio waves (ST1304). When terminal 1050 receives a response from base station 470, the connection with base station 470 via radio waves is completed (ST1305).

[0256] Terminal 1050 then transmits connection destination information to base station 470 using radio waves (ST1306).

[0257] Base station 470 obtains information to be transmitted to terminal 1050 from the network (ST1307).

[0258] Then, base station 470 transmits the obtained information to terminal 1050 using radio waves, and terminal 1050 receives the information (ST1308). Terminal 1050 obtains necessary information from the network via base station 470, for example, when necessary.

[0259] Fig. 23 is a flowchart showing a second example of the processing performed by the "third device 1400A," "fourth device 1400B," "terminal 1050," and "base station 470" shown in Fig. 19. In Fig. 23, the same numbers are used for components that operate in the same way as in Fig. 18.

[0260] First, fourth device 1400B transmits a modulated signal with the frame configuration shown in FIG. 21 (ST1801).

[0261] Terminal 1050 then receives the modulated signal transmitted by fourth device 1400B, and acquires the encryption key used for communication with base station 470 accessed by terminal 1050 (ST1802).

[0262] Next, third device 1400A transmits a modulated signal with the frame configuration shown in FIG. 20 (ST1803).

[0263] Terminal 1050 then receives the modulated signal transmitted by third device 1400A and acquires the SSID of base station 470 that terminal 1050 will access (ST1804).

[0264] Terminal 1050 then establishes a connection with base station 470 via radio waves (ST1304). When terminal 1050 receives a response from base station 470, the connection with base station 470 via radio waves is completed (ST1305).

[0265] Terminal 1050 then transmits connection destination information to base station 470 using radio waves (ST1306).

[0266] Base station 470 obtains information to be transmitted to terminal 1050 from the network (ST1307).

[0267] Then, base station 470 transmits the obtained information to terminal 1050 using radio waves, and terminal 1050 receives the information (ST1308). Terminal 1050 obtains necessary information from the network via base station 470, for example, when necessary.

[0268] As described above, based on the SSID transmitted from the third device 1400A and the encryption key information transmitted from the fourth device 1400B, the terminal 1050 connects to the base station 470 and acquires information. That is, the device from which the terminal 1050 acquires the SSID information is different from the device from which the terminal 1050 acquires the encryption key information, and therefore the terminal 1050 can securely acquire the information via the base station 470, whose security is guaranteed. This is because, when the terminal 1050 acquires information from a modulated signal of visible light, the user can easily determine whether the source of the information is secure because it is visible light. In contrast, for example, when the SSID is acquired from a modulated signal of radio waves transmitted by a wireless LAN, it is difficult for the user to identify the device that transmitted the radio waves. Therefore, in terms of ensuring the security of information, visible light communication is more suitable for acquiring an SSID than wireless LAN communication.

[0269] In the present embodiment, the case where fourth device 1400B transmits encryption key information has been described. However, for example, if base station 470 is not performing encrypted communication using an encryption key, encryption key information is not transmitted by fourth device 1400B, and only information related to the SSID needs to be transmitted by third device 1400A. In this case, the same implementation can be achieved by simply deleting the configuration related to the encryption key from the above-described configuration.

[0270] Furthermore, as in this embodiment, by separating the device that transmits information about the SSID (third device 1400A) from the device that transmits information about the encryption key (fourth device 1400B), terminal 1050 can achieve more secure communication with base station 470.

[0271] For example, consider a space like the one shown in Figure 24. In Figure 24, there are area #1 and area #2, and there is a doorway and a wall between area #1 and area #2. In other words, in the space of Figure 24, movement from area #1 to area #2 and from area #2 to area #1 can only be done through the doorway.

[0272] It is assumed that base station 470, third device 1400A, and fourth device 1400B are installed in area #1 in Fig. 24. On the other hand, it is assumed that only third device 1400A is installed in area #2. It is also assumed that radio waves transmitted by base station 470 in Fig. 24 can be received in both area #1 and area #2.

[0273] At this time, the terminal 1050 present in area #1 where the fourth device 1400B is installed can acquire the encryption key of the base station 470 from the fourth device 1400B and communicate with the base station 470. Furthermore, even if the terminal 1050 that has connected to the base station 470 in area #1 moves to area #2, it can still communicate with the base station 470 using the encryption key that it acquired from the fourth device 1400B in area #1. Furthermore, even if the terminal 1050 that has connected to the base station 470 in area #1 moves to an area other than area #1 or area #2 and then returns to either area #1 or area #2, it can still communicate with the base station 470 using the encryption key that it acquired from the fourth device 1400B in area #1.

[0274] On the other hand, terminal 1050, which cannot enter area #1, cannot obtain the encryption key from fourth device 1400B. In this case, terminal 1050 knows only the SSID of base station (or AP) 470. Therefore, for example, terminal 1050 may be able to communicate with base station 470 using services that can be enjoyed by knowing only the SSID of base station 470. The services that can be enjoyed by knowing only the SSID of base station 470 can be more limited than the services that can be enjoyed when both the SSID and the encryption key are known.

[0275] Therefore, only terminal 1050 that can enter area #1 can communicate with base station 470. This ensures the security of communications. It also makes it possible to build a system that can provide different services for each area.

[0276] Note that by changing the encryption key used by terminal 1050 to communicate with base station 470 (for example, at certain time intervals), terminal 1050 that holds the encryption key before the change will no longer be able to communicate with base station 470. By performing such an operation, it becomes possible to perform more secure communication.

[0277] Furthermore, the configuration of the third device and the configuration of the fourth device are not limited to the configurations of the third device 1400A and the fourth device 1400B shown in FIG. 19, the configuration of the terminal is not limited to the configuration of the terminal 1050 shown in FIG. 19, and the connection destination and configuration of the base station are not limited to the connection destination and configuration of the base station 470 shown in FIG. 19.

[0278] 19 illustrates a case where one base station 470 is installed, but there may be multiple (secure) base stations (or APs) accessible to terminal 1050. In this case, the symbol relating to the SSID transmitted by third device 1400A in FIG. 19 may include information on the SSID of each of the multiple base stations 470. Furthermore, the symbol relating to the encryption key transmitted by fourth device 1400B in FIG. 19 may include information on the encryption key used to connect to each of the multiple base stations. In this case, a list of SSIDs of the multiple base stations and / or a list of multiple access destinations is displayed on display 157 of terminal 1050 in FIG. 19 as a display of access destinations (the "first display" described above). Terminal 1050 in FIG. 19 may then select one or more base stations to actually connect to wirelessly based on the information on the SSIDs and encryption keys of the multiple base stations (i.e., may connect to multiple base stations simultaneously).

[0279] For example, suppose three base stations 470 are deployed. Here, the three base stations 470 are called base station #A, base station #B, and base station #C, respectively. Also, let the SSID of base station #A be "abcdef," the SSID of base station #B be "ghijk," and the SSID of base station #C be "pqrstu." Also, let the encryption key for connecting to base station #A be "123," the encryption key for connecting to base station #B be "456," and the encryption key for connecting to base station #C be "789."

[0280] In this case, symbol 600-1 relating to SSID in the frame configuration of Fig. 20 of the modulated signal transmitted by third device 1400A includes information that "the SSID of base station #A is 'abcdef'," "the SSID of base station #B is 'ghijk'," and "the SSID of base station #C is 'pqrstu'." Also, symbol 1101 relating to encryption key in the frame configuration of Fig. 21 of the modulated signal transmitted by fourth device 1400B includes information that "the encryption key for connecting with base station #A is '123'," "the encryption key for connecting with base station #B is '456'," and "the encryption key for connecting with base station #C is '789'."

[0281] 19 receives symbol 600-1 related to the SSID and obtains information such as "the SSID of base station #A is 'abcdef'," "the SSID of base station #B is 'ghijk'," and "the SSID of base station #C is 'pqrstu'." Terminal 1050 also receives symbol 1101 related to the encryption key and obtains information such as "the encryption key for connecting to base station #A is '123'," "the encryption key for connecting to base station #B is '456'," and "the encryption key for connecting to base station #C is '789'." Terminal 1050 then selects a base station to connect to wirelessly (for example, via radio waves) based on this information and connects to it.

[0282] Furthermore, by using a light source such as an LED as in the present embodiment to set the base station 470 to be accessed by the terminal 1050, a special setting mode for performing a procedure for connecting the terminal 1050 and the base station 470 for wireless communication is not required for the modulated signal for wireless communication transmitted by the terminal 1050. Furthermore, a special setting mode for performing a procedure for connecting the terminal 1050 and the base station 470 for wireless communication is not required for the modulated signal transmitted by the base station 470. Therefore, in the present embodiment, it is possible to improve the data transmission efficiency of wireless communication.

[0283] Furthermore, as described above, the encryption key may be an encryption key for the SSID of a wireless LAN, or may be an encryption key for restricting the connection type, service type, network connection range, etc. In other words, it is sufficient if an encryption key is introduced for some kind of restriction.

[0284] (Embodiment 6) FIG. 25 is a diagram showing an example of the configuration of a communication system according to this embodiment.

[0285] The communication system in Fig. 25 includes, for example, base station 2000 and terminal 1050. Base station 2000 also includes transmitting device 2001 and wireless device 2002. Note that in Fig. 25, components that operate in the same manner as in Fig. 6 and Fig. 15 are assigned the same numbers. Also, communication between wireless device 2002 and wireless device 453 in Fig. 25 is assumed to use, for example, radio waves.

[0286] 25 includes a visible light source such as an LED, illumination, light source, or light (hereinafter referred to as light source 104). First, the operation of transmission device 2001 (that is, the "part related to the visible light source such as an LED, illumination, light source, or light") will be described.

[0287] In transmitting device 2001, transmitting unit 102 receives as input information 1001-1 related to SSID, information 1001-2 related to encryption key, and data 1002, generates (optical) modulated signal 103 based on these input signals, and outputs modulated signal 103. Modulated signal 103 is then transmitted from light source 104, for example.

[0288] Next, the information 1001-1 about the SSID and the information 1001-2 about the encryption key will be described.

[0289] First, the information 1001-1 relating to the SSID will be described.

[0290] Information 1001-1 related to SSID is information indicating the SSID of wireless device 2002 that uses radio waves, of base station 2000 in Fig. 25. In other words, transmitting device 2001 can provide terminal 1050 with secure wireless access to wireless device 2002, which is the access destination. This allows terminal 1050 in Fig. 25 to securely obtain information from wireless device 2002.

[0291] On the other hand, the transmitting device 2001 can limit the terminals that can access the wireless device 2002 to terminals located in a space that can receive the optical signal transmitted (irradiated) by the transmitting device 2001.

[0292] When the terminal 1050 receives an optical signal transmitted in a predetermined manner, the terminal 1050 may determine that the notified SSID is the SSID of a secure base station. The terminal 1050 may also perform a separate process to determine whether the notified SSID is secure. For example, the transmitting device 2001 may transmit an optical signal including a predetermined identifier, and the terminal 1050 may determine whether the notified SSID is the SSID of a secure base station based on the received identifier.

[0293] Although only base station 2000 is shown in FIG. 25, even if there is a base station (or AP) other than base station 2000, terminal 1050 will access wireless device 2002 of base station 2000 using the SSID and encryption key obtained from transmitting device 2001 to obtain information.

[0294] Next, the information 1001-2 relating to the encryption key will be described.

[0295] The information 1001-2 relating to the encryption key is information relating to the encryption key that is required for the terminal 1050 to communicate with the wireless device 2002. By obtaining the information 1001-2 relating to the encryption key from the transmitting device 2001, the terminal 1050 becomes able to perform encrypted communication with the wireless device 2002.

[0296] The information 1001-1 relating to the SSID and the information 1001-2 relating to the encryption key have been described above.

[0297] Terminal 1050 in Fig. 25 receives the modulated signal transmitted by transmitting device 2001. Note that in terminal 1050 in Fig. 25, components that operate in the same manner as terminal 150 in Fig. 6 and terminal 1050 in Fig. 15 are assigned the same numbers.

[0298] The light receiving unit 151 included in the terminal 1050 is, for example, an image sensor such as a CMOS or an organic CMOS. The light receiving unit 151 receives light including a modulated signal transmitted from the transmitting device 2001, and outputs a received signal 152.

[0299] The receiving unit 153 receives the received signal 152 received by the light receiving unit 151 as input, performs processing such as demodulation and error correction decoding on the modulated signal included in the received signal 152 , and outputs received data 154 .

[0300] Data analysis unit 155 receives received data 154 as input and outputs, from the received data, for example, SSID information 1051 of wireless device 2002 of destination base station 2000 and encryption key information 1052 for communicating with wireless device 2002 of destination base station 2000. For example, in a wireless LAN (Local Area Network), encryption methods include WEP (Wired Equivalent Privacy), WPA (Wi-Fi Protected Access), and WPA2 (Wi-Fi Protected Access 2) (PSK (Pre-Shared Key) mode, EAP (Extended Authentication Protocol) mode). However, encryption methods are not limited to these.

[0301] Display unit 157 receives SSID information 1051 and encryption key information 1052 as input, and displays, for example, the SSID and encryption key of the communication partner accessed by wireless device 453 provided in terminal 1050 (this display is referred to as the "first display" in this embodiment).

[0302] For example, after the first display, wireless device 453 receives SSID information 1051 and encryption key information 1052 as input and establishes a connection with wireless device 2002 of base station 2000 (for example, the connection is assumed to be via radio waves). At this time, when wireless device 2002 of base station 2000 communicates with wireless device 453 included in terminal 1050, it also transmits a modulated signal using, for example, radio waves.

[0303] Thereafter, wireless device 453 receives data 1053 and control signal 1054 as input, modulates data 1053 in accordance with the control indicated by control signal 1054, and transmits the modulated signal via radio waves.

[0304] Then, for example, wireless device 2002 of base station 2000 transmits data to the network (471) and receives data from the network (472). After that, for example, wireless device 2002 of base station 2000 transmits a modulated signal to terminal 1050 by radio waves.

[0305] The wireless device 453 included in the terminal 1050 performs processes such as demodulation and error correction decoding on the modulated signal received via radio waves, and acquires received data 1056. The display unit 157 displays based on the received data 1056.

[0306] The frame structure of a modulated signal transmitted by transmitting device 2001 of base station 2000 in this embodiment is the same as the frame structure shown in Fig. 16 described in Embodiment 4. That is, in Fig. 16, symbol 600-1 related to SSID is a symbol for transmitting information 1001-1 related to SSID in Fig. 25, and symbol 1101 related to encryption key is a symbol for transmitting information 1001-2 related to encryption key in Fig. 25. Data symbol 1102 is a symbol for transmitting data 1002 in Fig. 25.

[0307] As shown in Fig. 16, transmitting device 2001 of base station 2000 transmits preamble 201, control information symbol 202, SSID-related symbol 600-1, encryption key-related symbol 1101, and data symbol 1102. Note that transmitting device 2001 of base station 2000 may transmit a frame including symbols other than those shown in Fig. 16. Furthermore, the frame configuration, including the order in which the symbols are transmitted, is not limited to that shown in Fig. 16.

[0308] The frame structure of the modulated signal transmitted by radio equipment 453 included in terminal 1050 in this embodiment is the same as the frame structure shown in Fig. 17 described in embodiment 4. That is, as shown in Fig. 17, radio equipment 453 included in terminal 1050 in Fig. 25 transmits, for example, preamble 1201, and then transmits control information symbol 1202 and information symbol 1203.

[0309] In this case, the preamble 1201 is a symbol used by the wireless device 2002 of the base station 2000 that receives the modulated signal transmitted by the wireless device 453 to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, etc.

[0310] The control information symbol 1202 is a symbol containing data such as the error correction coding method used by the terminal 1050 to generate the modulated signal, information about the modulation method, information about the frame structure, information about the transmission method, etc. The wireless device 2002 of the base station 2000 demodulates the modulated signal based on the information contained in the control information symbol 1202.

[0311] Information symbols 1203 are symbols used by radio equipment 453 of terminal 1050 to transmit data.

[0312] Note that radio equipment 453 of terminal 1050 may transmit a frame including symbols other than those shown in Fig. 17. For example, radio equipment 453 may transmit a frame including a pilot symbol (reference symbol) in the middle of information symbol 1203. Also, the frame configuration, including the order in which symbols are transmitted, is not limited to that shown in Fig. 17. Also, in Fig. 17, multiple symbols may exist in the frequency axis direction. That is, in Fig. 17, symbols may exist at multiple frequencies (multiple carriers).

[0313] The frame structure of the modulated signal transmitted by radio device 2002 in this embodiment is the same as the frame structure shown in Fig. 12 described in embodiment 3. That is, as shown in Fig. 12, radio device 2002 transmits, for example, preamble 701, and then transmits control information symbol 702 and information symbol 703.

[0314] Preamble 701 is a symbol used by radio device 453 of terminal 1050, which receives the modulated signal transmitted by radio device 2002, to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, and the like.

[0315] The control information symbol 702 is a symbol containing data such as the error correction coding method used to generate the modulated signal, information about the modulation method, information about the frame structure, information about the transmission method, etc. The wireless device 453 of the terminal 1050 demodulates the modulated signal based on the information in the control information symbol 702.

[0316] Information symbols 703 are symbols used by wireless device 2002 to transmit data.

[0317] Note that radio equipment 2002 of base station 2000 shown in Fig. 25 may transmit a frame including symbols other than those shown in Fig. 12. For example, radio equipment 2002 may transmit a frame including a pilot symbol (reference symbol) in the middle of information symbols 703. Also, the frame configuration, including the order in which symbols are transmitted, is not limited to that shown in Fig. 12. Also, in Fig. 12, multiple symbols may exist in the frequency axis direction. That is, in Fig. 12, symbols may exist at multiple frequencies (multiple carriers).

[0318] 16 transmitted by transmitting device 2001 at regular timing, for example, repeatedly, which allows multiple terminals 1050 to perform the operations described above.

[0319] FIG. 26 is a flowchart showing an example of processing performed by the "transmitting device 2001 of the base station 2000," the "terminal 1050," and the "wireless device 2002 of the base station 2000" shown in FIG.

[0320] First, transmitting apparatus 2001 transmits a modulated signal with the frame configuration shown in FIG. 16 (ST1301).

[0321] Terminal 1050 then receives the modulated signal transmitted by transmitting apparatus 2001 and acquires the SSID of base station 2000 (wireless apparatus 2002) that terminal 1050 will access (ST1302).

[0322] At the same time, terminal 1050 acquires an encryption key to be used for communication with base station 2000 (wireless device 2002) that terminal 1050 accesses (ST1303).

[0323] Terminal 1050 then establishes a connection with radio equipment 2002 of base station 2000 via radio waves (ST1304). When terminal 1050 receives a response from radio equipment 2002 of base station 2000, the connection between terminal 1050 and radio equipment 2002 of base station 2000 is completed (ST1305).

[0324] Terminal 1050 then transmits connection destination information to radio equipment 2002 of base station 2000 using radio waves (ST1306).

[0325] Radio equipment 2002 of base station 2000 obtains information to be transmitted to terminal 1050 from the network (ST1307).

[0326] Then, wireless device 2002 of base station 2000 transmits the obtained information to terminal 1050 using radio waves, and terminal 1050 receives the information (ST1308). Terminal 1050 obtains necessary information from the network via wireless device 2002 of base station 2000, for example, when necessary.

[0327] As described above, terminal 1050 connects to wireless device 2002 of base station 2000 based on the SSID information and encryption key information transmitted from transmitter 2001 of base station 2000, and acquires the information, thereby enabling secure acquisition of the information via base station 2000, whose security is guaranteed. This is because, when terminal 1050 acquires the information from a modulated signal of visible light, it is easy for the user to determine whether the source of the information is secure because it is visible light. In contrast, for example, when the SSID is acquired from a modulated signal of radio waves transmitted by a wireless LAN, it is difficult for the user to identify the device that transmitted the radio waves. Therefore, in terms of ensuring the security of the information, visible light communication is more suitable for acquiring the SSID than wireless LAN communication.

[0328] In the present embodiment, the case where transmitting device 2001 transmits encryption key information has been described. However, for example, if wireless device 2002 of base station 2000 is not performing encrypted communication using an encryption key, transmitting device 2001 may transmit only information related to the SSID without transmitting encryption key information. In this case, the same implementation can be achieved by simply deleting the configuration related to the encryption key from the configuration of transmitting device 2001.

[0329] 25, the SSID and encryption key of wireless device 2002 of base station 2000 may be rewritable. For example, in FIG. 25, information 1001-1 related to the SSID and information 1001-2 related to the encryption key are input to wireless device 2002. Wireless device 2002 of base station 2000 rewrites the SSID and encryption key based on the input information 1001-1 related to the SSID and information 1001-2 related to the encryption key. This further ensures the security of communications between terminal 1050 and wireless device 2002 of base station 2000. Note that, although FIG. 25 shows wireless device 2002 of base station 2000 having a function for rewriting the SSID and encryption key, the configuration may be such that it does not have the function for rewriting both or either of the SSID and the encryption key.

[0330] Furthermore, the configuration of the transmitting device is not limited to the configuration of transmitting device 2001 shown in Figure 25, the configuration of the terminal is not limited to the configuration of terminal 1050 shown in Figure 25, and the connection destination and configuration of the wireless device are not limited to the connection destination and configuration of wireless device 2002 shown in Figure 25.

[0331] 25 illustrates a case where one base station 2000 is installed, but there may be multiple wireless devices 2002 of base stations (or APs) 2000 accessible (secure) by terminal 1050. The wireless devices 2002 of these multiple base stations 2000 and terminal 1050 transmit and receive modulated signals using radio waves. At this time, the symbol relating to the SSID transmitted by transmitting device 2001 in FIG. 25 may include information on the SSID of each of the wireless devices 2002 of these multiple base stations 2000. The symbol relating to the encryption key transmitted by transmitting device 2001 in FIG. 25 may include information on the encryption key used to connect to each of the wireless devices 2002 of these multiple base stations 2000. Then, terminal 1050 in FIG. 25 may select wireless device 2002 of base station 2000 to connect to wirelessly (e.g., via radio waves) based on SSID information and encryption key information of wireless device 2002 of multiple base stations 2000 (or may connect to wireless devices of multiple base stations).

[0332] For example, assume that there are three base stations 2000 each equipped with a wireless device 2002. Here, the wireless devices 2002 of the three base stations 2000 are called wireless device #A, wireless device #B, and wireless device #C, respectively. Also, assume that the SSID of wireless device #A is "abcdef," the SSID of wireless device #B is "ghijk," and the SSID of wireless device #C is "pqrstu." Also, assume that the encryption key for connecting to wireless device #A is "123," the encryption key for connecting to wireless device #B is "456," and the encryption key for connecting to wireless device #C is "789."

[0333] In this case, symbol 600-1 relating to SSID in the frame configuration of Fig. 16 of the modulated signal transmitted by transmitting device 2001 includes information that "the SSID of wireless device #A is 'abcdef'," "the SSID of wireless device #B is 'ghijk'," and "the SSID of wireless device #C is 'pqrstu'." Also, symbol 1101 relating to encryption key in the frame configuration of Fig. 16 includes information that "the encryption key for connecting with wireless device #A is '123'," "the encryption key for connecting with wireless device #B is '456'," and "the encryption key for connecting with wireless device #C is '789'."

[0334] 25 receives symbol 600-1 related to the SSID and obtains information such as "the SSID of wireless device #A is 'abcdef'," "the SSID of wireless device #B is 'ghijk'," and "the SSID of wireless device #C is 'pqrstu'." Terminal 1050 also receives symbol 1101 related to the encryption key and obtains information such as "the encryption key for connecting with wireless device #A is '123'," "the encryption key for connecting with wireless device #B is '456'," and "the encryption key for connecting with wireless device #C is '789'." Terminal 1050 then selects a base station to connect to wirelessly (for example, by radio waves) based on this information and connects to it.

[0335] Furthermore, as in the present embodiment, by using a light source, such as an LED, to configure wireless device 2002 of base station 2000 accessed by terminal 1050, a special setting mode for performing a procedure for establishing a wireless communication connection between terminal 1050 and base station 2000 is not required for the wireless modulation signal transmitted by terminal 1050. Also, a special setting mode for performing a procedure for establishing a wireless communication connection between terminal 1050 and base station 2000 is not required for the wireless modulation signal transmitted by base station 2000. Therefore, in the present embodiment, it is possible to improve the data transmission efficiency of wireless communication.

[0336] Furthermore, as described above, the encryption key may be an encryption key for the SSID of a wireless LAN, or may be an encryption key for restricting the connection type, service type, network connection range, etc. In other words, it is sufficient if an encryption key is introduced for some kind of restriction.

[0337] (Embodiment 7) FIG. 27 is a diagram showing an example of the configuration of a communication system according to this embodiment.

[0338] The communication system in Fig. 27 includes device 1000, terminal 1050, and base station (or AP) 470-1 (base station #1), base station (or AP) 470-2 (base station #2), and base station (or AP) 470-3 (base station #3) that communicate with terminal 1050. Note that in Fig. 27, components that operate in the same way as in Figs. 6, 9, and 15 are assigned the same numbers.

[0339] The device 1000 includes, for example, visible light such as an LED, illumination, a light source, or a light (light source 104). Note that hereinafter, the device 1000 is referred to as the "fifth device" in this embodiment. Also, it is assumed that the communication between the wireless device 453 and the base station 470-1 (base station #1), the communication between the wireless device 453 and the base station 470-2 (base station #2), and the communication between the wireless device 453 and the base station 470-3 (base station #3) in FIG. 27 uses, for example, radio waves.

[0340] 27, transmitter 102 receives information 1001-1 related to SSID, information 1001-2 related to encryption key, and data 1002 as input, generates (optical) modulated signal 103 based on these input signals, and outputs modulated signal 103. Modulated signal 103 is then transmitted from light source 104, for example.

[0341] Next, the information 1001-1 about the SSID and the information 1001-2 about the encryption key will be described.

[0342] First, the information 1001-1 relating to the SSID will be described.

[0343] SSID-related information 1001-1 includes, for example, information indicating the SSID of base station 470-1 (base station #1) in FIG. 27, information indicating the SSID of base station 470-2 (base station #2), and information indicating the SSID of base station 470-3 (base station #3). Note that, as an example, base stations 470-1, 470-2, and 470-3 transmit modulated signals via radio waves and receive modulated signals via radio waves. That is, fifth device 1000 can provide terminal 1050 with access to base stations 470-1, 470-2, and 470-3, which are secure access destinations. This allows terminal 1050 in FIG. 27 to securely obtain information from base stations 470-1, 470-2, and 470-3.

[0344] On the other hand, the fifth device 1000 can limit the terminals that access the base stations 470-1, 470-2, and 470-3 to terminals located in a space that can receive the optical signal transmitted (irradiated) by the fifth device 1000.

[0345] Note that when terminal 1050 receives an optical signal transmitted in a predetermined manner, it may determine that the notified SSID is the SSID of a secure base station. Furthermore, terminal 1050 may separately perform processing to determine whether the notified SSID is secure. For example, fifth device 1000 may transmit an optical signal including a predetermined identifier, and terminal 1050 may determine whether the notified SSID is the SSID of a secure base station based on the received identifier.

[0346] Although FIG. 27 shows base stations 470-1, 470-2, and 470-3, for example, base stations (or APs) other than base stations 470-1, 470-2, and 470-3 may also be present.

[0347] Next, the information 1001-2 relating to the encryption key will be described.

[0348] Encryption key information 1001-2 is information about the encryption key that is required for terminal 1050 to communicate with base stations 470-1, 470-2, and 470-3. By obtaining encryption key information 1001-2 from fifth device 1000, terminal 1050 becomes able to perform encrypted communications "between terminal 1050 and base station 470-1," "between terminal 1050 and base station 470-2," and "between terminal 1050 and base station 470-3."

[0349] The information 1001-1 relating to the SSID and the information 1001-2 relating to the encryption key have been described above.

[0350] Terminal 1050 in Fig. 27 receives a modulated signal transmitted by fifth device 1000. Note that in terminal 1050 in Fig. 27, components that operate in the same manner as terminal 150 in Fig. 6 and terminal 450 in Fig. 9 are assigned the same numbers.

[0351] The light receiving unit 151 included in the terminal 1050 is, for example, an image sensor such as a CMOS or an organic CMOS. The light receiving unit 151 receives light including a modulated signal transmitted from the fifth device 1000, and outputs a received signal 152.

[0352] The receiving unit 153 receives the received signal 152 received by the light receiving unit 151 as input, performs processing such as demodulation and error correction decoding on the modulated signal included in the received signal 152 , and outputs received data 154 .

[0353] Data analysis unit 155 receives received data 154 as input and outputs, for example, SSID information 1051 of destination base stations 470-1, 470-2, and 470-3 and encryption key information 1052 for communicating with destination base stations 470-1, 470-2, and 470-3 from received data 154. For example, encryption methods for a wireless LAN (Local Area Network) include WEP (Wired Equivalent Privacy), WPA (Wi-Fi Protected Access), and WPA2 (Wi-Fi Protected Access 2) (PSK (Pre-Shared Key) mode and EAP (Extended Authentication Protocol) mode). However, encryption methods are not limited to these.

[0354] Display unit 157 receives SSID information 1051 and encryption key information 1052 as input, and displays, for example, the SSID and encryption key of the communication partner accessed by wireless device 453 provided in terminal 1050 (this display is referred to as the "first display" in this embodiment).

[0355] For example, after the first display, wireless device 453 receives SSID information 1051 and encryption key information 1052 and establishes a connection with one of base stations 470-1, 470-2, or 470-3 (for example, the connection is assumed to be via radio waves). At this time, when connected base station 470 communicates with wireless device 453 included in terminal 1050, it also transmits a modulated signal using, for example, radio waves.

[0356] Thereafter, wireless device 453 receives data 1053 and control signal 1054 as input, modulates data 1053 in accordance with the control indicated by control signal 1054, and transmits the modulated signal as radio waves.

[0357] Then, for example, the connected base station 470 transmits data to the network (471-1, 471-2, or 471-3) and receives data from the network (472-1, 472-2, or 472-3). After that, for example, the connected base station 470 transmits a modulated signal to the terminal 1050 by radio waves.

[0358] The wireless device 453 included in the terminal 1050 performs processes such as demodulation and error correction decoding on the modulated signal received via radio waves, and acquires received data 1056. The display unit 157 displays based on the received data 1056.

[0359] In the case of Fig. 27, there are three types of frame configurations for the modulated signal transmitted by fifth device 1000. Fig. 28 shows frame 2300-1 (frame #1), which is one of the three types of frame configurations, Fig. 29 shows frame 2300-2 (frame configuration #2), which is one of the three types of frame configurations, and Fig. 30 shows frame 2300-3 (frame configuration #3), which is one of the three types of frame configurations.

[0360] Fig. 28 shows an example of the configuration of frame 2300-1 (frame #1) of a modulated signal transmitted by fifth device 1000. In Fig. 28, the horizontal axis represents time. Furthermore, in Fig. 28, the same symbols as in Figs. 2 and 16 are assigned the same numbers, and descriptions thereof will be omitted. Frame 2300-1 (frame #1) in Fig. 28 is a frame for transmitting information on the SSID of base station 470-1 (base station #1) in Fig. 27 and information on the encryption key of base station 470-1 (base station #1) (encryption key for accessing base station 470-1).

[0361] Symbol 2301-1 relating to SSID is a symbol for transmitting information 1001-1 relating to SSID in Fig. 27. Also, symbol 2301-1 relating to SSID is a symbol for fifth device 1000 in Fig. 27 to transmit the SSID of base station 470-1 (base station #1).

[0362] Symbol 2302-1 relating to the encryption key is a symbol for transmitting information 1001-2 relating to the encryption key in Fig. 27. Also, symbol 2302-1 relating to the encryption key is a symbol for fifth device 1000 in Fig. 27 to transmit the encryption key (encryption key for accessing base station 470-1) of base station 470-1 (base station #1).

[0363] Fifth device 1000 transmits preamble 201, control information symbol 202, SSID-related symbol 2301-1, encryption key-related symbol 2302-1, and data symbol 1102. Note that fifth device 1000 may transmit frame 2300-1 (frame #1) including symbols other than those shown in Fig. 28. Also, the configuration of frame 2300-1 (frame #1), including the order in which the symbols are transmitted, is not limited to the configuration in Fig. 28.

[0364] Fig. 29 shows an example of the configuration of frame 2300-2 (frame #2) of a modulated signal transmitted by fifth device 1000. In Fig. 29, the horizontal axis represents time. Furthermore, in Fig. 29, the same symbols as in Figs. 2 and 16 are assigned the same numbers, and descriptions thereof will be omitted. Frame 2300-2 (frame #2) in Fig. 29 is a frame for transmitting information on the SSID of base station 470-2 (base station #2) in Fig. 27 and information on the encryption key of base station 470-2 (base station #2) (encryption key for accessing base station 470-2).

[0365] Symbol 2301-2 relating to SSID is a symbol for transmitting information 1001-1 relating to SSID in Fig. 27. Also, symbol 2301-2 relating to SSID is a symbol for fifth device 1000 in Fig. 27 to transmit the SSID of base station 470-2 (base station #2).

[0366] Symbol 2302-2 relating to the encryption key is a symbol for transmitting information 1001-2 relating to the encryption key in Fig. 27. Also, symbol 2302-2 relating to the encryption key is a symbol for fifth device 1000 in Fig. 27 to transmit the encryption key (encryption key for accessing base station 470-2) of base station 470-2 (base station #2).

[0367] Fifth device 1000 transmits preamble 201, control information symbol 202, SSID-related symbol 2301-2, encryption key-related symbol 2302-2, and data symbol 1102. Note that fifth device 1000 may transmit frame 2300-2 (frame #2) including symbols other than those shown in Fig. 29. Also, the configuration of frame 2300-2 (frame #2), including the order in which the symbols are transmitted, is not limited to the configuration in Fig. 29.

[0368] Fig. 30 shows an example of the configuration of frame 2300-3 (frame #3) of a modulated signal transmitted by fifth device 1000. In Fig. 30, the horizontal axis represents time. Furthermore, in Fig. 30, the same symbols as in Figs. 2 and 16 are assigned the same numbers, and descriptions thereof will be omitted. Frame 2300-3 (frame #3) in Fig. 30 is a frame for transmitting information on the SSID of base station 470-3 (base station #3) in Fig. 27 and information on the encryption key of base station 470-3 (base station #3) (encryption key for accessing base station 470-3).

[0369] Symbol 2301-3 relating to SSID is a symbol for transmitting information 1001-1 relating to SSID in Fig. 27. Also, symbol 2301-3 relating to SSID is a symbol for fifth device 1000 in Fig. 27 to transmit the SSID of base station 470-3 (base station #3).

[0370] Symbol 2302-3 relating to the encryption key is a symbol for transmitting information 1001-2 relating to the encryption key in Fig. 27. Also, symbol 2302-3 relating to the encryption key is a symbol for fifth device 1000 to transmit the encryption key of base station 470-3 (base station #3) (encryption key for accessing base station 470-3).

[0371] Fifth device 1000 transmits preamble 201, control information symbol 202, SSID-related symbol 2301-3, encryption key-related symbol 2302-3, and data symbol 1102. Note that fifth device 1000 may transmit frame 2300-3 (frame #3) including symbols other than those shown in Fig. 30. Furthermore, the configuration of frame 2300-3 (frame #3), including the order in which the symbols are transmitted, is not limited to the configuration in Fig. 30.

[0372] Fig. 31 shows an example of a transmission method when fifth device 1000 transmits "frame 2300-1 (frame #1) of Fig. 28," "frame 2300-2 (frame #2) of Fig. 29," and "frame 2300-3 (frame #3) of Fig. 30." In Fig. 31, the horizontal axis represents time.

[0373] In Fig. 31, "frame #1 group transmission" 2601-1, 2601-2 transmit one or more frames 2300-1 (frame #1) in Fig. 28. Also, "frame #2 group transmission" 2602-1, 2602-2 transmit one or more frames 2300-2 (frame #2) in Fig. 29. Also, "frame #3 group transmission" 2603-1, 2603-2 transmit one or more frames 2300-3 (frame #3) in Fig. 30.

[0374] A detailed explanation of this will be given below.

[0375] First, the fact that one or more frames 2300-1 (frame #1) in FIG. 28 are transmitted in "frame #1 group transmission" 2601-1 and 2601-2 will be described.

[0376] For example, if an image sensor such as a CMOS or organic CMOS is used in the light receiving unit 151, the received signal may be processed on a frame-by-frame basis for moving or still images. For example, when it is written "4K 30p" for moving images, it means that the number of pixels in one frame is 3840 x 2160, and the number of frames per second is 30.

[0377] Therefore, if fifth device 1000 transmits a modulated signal configured such that one frame contains "frame 2300-1 (frame #1) of FIG. 28," "frame 2300-2 (frame #2) of FIG. 29," and "frame 2300-3 (frame #3) of FIG. 30," it becomes difficult for terminal 1050 of FIG. 27 to select base station 470 to access from multiple base stations 470-1, 470-2, and 470-3.

[0378] Therefore, in this embodiment, a frame configuration as shown in FIG. 31 is proposed.

[0379] <Method 1-1> In method 1-1, each of "frame #1 group transmission" 2601-1, 2601-2 includes multiple frames 2300-1 (frame #1) in Figure 28, so that the time period occupied by each of "frame #1 group transmission" 2601-1, 2601-2 is longer than the time of a frame in a video or still image.

[0380] This makes it possible to prevent terminal 1050 from receiving, from fifth device 1000, modulated signals including "frame 2300-1 (frame #1) in FIG. 28," "frame 2300-2 (frame #2) in FIG. 29," and "frame 2300-3 (frame #3) in FIG. 30," that is, different SSIDs and encryption keys, within one frame of a moving image or still image. Thus, terminal 1050 in FIG. 27 can easily select base station 470 to access from multiple base stations 470-1, 470-2, 470-3.

[0381] <Method 2-1> As a method 2-1, the time period occupied by frame 2300-1 (frame #1) in FIG. 28 is set to be longer than that of a frame in a moving image or a still image.

[0382] For example, the symbol 2301-1 relating to the SSID in FIG. 28 may include multiple pieces of "information on the SSID of base station #1" (i.e., "information on the SSID of base station #1" is repeatedly included), and the symbol 2302-1 relating to the encryption key may include multiple pieces of "information on the encryption key of base station #1 (information on the encryption key for connecting to base station #1)" (i.e., "information on the encryption key of base station #1 (information on the encryption key for connecting to base station #1)" is repeatedly included).

[0383] This makes it possible to prevent terminal 1050 from receiving, from fifth device 1000, modulated signals including "frame #1 of 2300-1 in FIG. 28," "frame #2 of 2300-2 in FIG. 29," and "frame #3 of 2300-3 in FIG. 30," that is, different SSIDs and encryption keys, within one frame of a moving image or still image. Thus, terminal 1050 can easily select base station 470 to access from multiple base stations 470-1, 470-2, and 470-3.

[0384] Similarly, the "frame #2 group transmission" 2602-1 and 2602-2 may have the following configuration.

[0385] <Method 1-2> In method 1-2, each of the "frame #2 group transmissions" 2602-1 and 2602-2 includes multiple frames 2300-2 (frame #2) in FIG. 29, so that the time period occupied by the "frame #2 group transmissions" is longer than that of a frame in a video or still image.

[0386] <Method 2-2> As a method 2-2, the time period occupied by frame 2300-2 (frame #2) in FIG. 29 is set to be longer than that of a frame in a moving image or a still image.

[0387] For example, the symbol 2301-2 relating to the SSID in FIG. 29 may include multiple pieces of "information on the SSID of base station #2" (i.e., "information on the SSID of base station #2" is repeatedly included), and the symbol 2302-2 relating to the encryption key may include multiple pieces of "information on the encryption key of base station #2 (information on the encryption key for connecting to base station #2)" (i.e., "information on the encryption key of base station #2 (information on the encryption key for connecting to base station #2)" is repeatedly included).

[0388] Similarly, it is preferable that "frame #3 group transmission" 2603-1 and 2603-2 have the following configuration.

[0389] <Methods 1-3> In method 1-3, each of the "frame #3 group transmissions" 2603-1 and 2603-2 includes multiple frames 2300-3 (frame #3) in Figure 30, so that the time period occupied by the "frame #3 group transmissions" is longer than the time of a frame in a video or still image.

[0390] <Method 2-3> As a second-third method, the time period occupied by frame 2300-3 (frame #3) in FIG. 30 is set to be longer than that of a frame in a moving image or a still image.

[0391] For example, the symbol 2301-3 relating to the SSID in FIG. 30 may include multiple pieces of "information on the SSID of base station #3" (i.e., "information on the SSID of base station #3" is repeatedly included), and the symbol 2302-3 relating to the encryption key may include multiple pieces of "information on the encryption key of base station #3 (information on the encryption key for connecting to base station #3)" (i.e., "information on the encryption key of base station #3 (information on the encryption key for connecting to base station #3)" is repeatedly included).

[0392] Next, the effect when the fifth device 1000 transmits frames as shown in FIGS. 28 to 31 will be described.

[0393] As an example, consider the area 2700 in Fig. 32. In Fig. 32, fifth devices 1000 are placed at the positions of "circles" 2701-1, 2701-2, 2701-3, 2701-4, 2701-5, 2701-6, 2701-7, 2701-8, 2701-9, and 2701-10. In addition, base station 470-1 (base station #1) is placed at the position of "◎" 2702-1, base station 470-2 (base station #2) is placed at the position of "◎" 2702-2, and base station 470-3 (base station #3) is placed at the position of "◎" 2702-3.

[0394] For example, it is assumed that there are 99 terminals (hereinafter simply referred to as terminals 1050) that have the same configuration as that of terminal 1050 inside area 2703.

[0395] At this time, for example, the fifth devices 1000 located at the positions of the "circles" 2701-5 and 2701-10 both transmit information about the SSID of the base station 470-3 (base station #3) and information about the encryption key for accessing the base station 470-3 (base station #3). This is because the base station 470-3 (base station #3) is the closest base station to the positions of the "circles" 2701-5 and 2701-10.

[0396] In this case, all 99 terminals 1050 will access base station 470-3 (base station #3). This increases the likelihood that some terminals 1050 will have difficulty accessing base station 470-3 (base station #3) due to access concentration.

[0397] Taking this into consideration, by controlling the 99 terminals 1050 to access base station 470-1 (base station #1) (position of "◎" 2702-1), base station 470-2 (base station #2) (position of [◎] 2702-2), and base station 470-3 (base station #3) (position of [◎] 2702-3) as evenly as possible, it is possible to reduce the number of terminals 1050 that have difficulty accessing base station 470, as described above.

[0398] For example, the timing at which 99 terminals 1050 access the fifth device 1000 will generally be different. Therefore, if the fifth device 1000 transmits frames as shown in FIGS. 28 to 31 as in this embodiment, each of the 99 terminals 1050 will acquire the SSID and encryption key of one of base stations 470-1, 470-2, and 470-3 depending on the timing at which it accesses the fifth device 1000. This results in "control being performed so that the 99 terminals 1050 access base stations 470-1, 470-2, and 470-3 as evenly as possible." Therefore, it is possible to reduce the presence of terminals 1050 that have difficulty accessing base station 470, as described above.

[0399] 31 shows an example of a transmission method when the fifth device 1000 transmits "frame 2300-1 (frame #1) of FIG. 28," "frame 2300-2 (frame #2) of FIG. 29," and "frame 2300-3 (frame #3) of FIG. 30." However, the transmission method when the fifth device 100 transmits "frame 2300-1 (frame #1) of FIG. 28," "frame 2300-2 (frame #2) of FIG. 29," and "frame 2300-3 (frame #3) of FIG. 30" is not limited to this.

[0400] For example, FIG. 31 shows a configuration in which the fifth device 1000 repeatedly transmits "frame #1 group transmission," "frame #2 group transmission," and "frame #3 group transmission" in that order, but "frame #1 group transmission," "frame #2 group transmission," and "frame #3 group transmission" do not have to be transmitted in the order shown in FIG. 31. Alternatively, for example, the fifth device 1000 may transmit "frame group 1 transmission," "frame group #2 transmission," and "frame group #3 transmission" randomly over time, or the order of "frame group 1 transmission," "frame group #2 transmission," and "frame group #3 transmission" may be transmitted in a regular order different from that shown in FIG. 31. It is sufficient that the fifth device 1000 transmits at least "frame #1 group transmission," "frame #2 group transmission," and "frame #3 group transmission."

[0401] 31, the fifth device 1000 successively transmits "frame #1 group transmission," "frame #2 group transmission," and "frame #3 group transmission," but these do not necessarily have to be transmitted successively. For example, in FIG. 31, there may be a time interval between frame #1 group 2601-1 and frame #2 group transmission 2602-2.

[0402] 31 is configured with only "frame #1 group transmission," "frame #2 group transmission," and "frame #3 group transmission," but other symbols and other frames may be present. Furthermore, in FIG. 31 and FIG. 27, the number of base stations 470 is three, but the number of base stations 470 is not limited to this. Even if there are two or more base stations 470, it is possible to operate in the same way as when there are three base stations 470. Therefore, for example, when there are N base stations 470 (N is an integer equal to or greater than 2), if fifth device 1000 performs transmission as shown in FIG. 31, there will be a "frame #k group transmission." Note that k is an integer equal to or greater than 1 and equal to or less than N. The "frame #k group transmission" includes a symbol related to the SSID (information about the SSID of base station #k) and a symbol related to the encryption key (information about the encryption key for accessing base station #k).

[0403] The frame structure of the modulated signal transmitted by radio equipment 453 included in terminal 1050 in Fig. 27 is the same as the frame structure in Fig. 17 described in embodiment 4. That is, as shown in Fig. 17, radio equipment 453 included in terminal 1050 in Fig. 27 transmits, for example, preamble 1201, and then transmits control information symbol 1202 and information symbol 1203.

[0404] Preamble 1201 is a symbol used by base stations 470-1, 470-2, and 470-3 that receive the modulated signal transmitted by wireless device 453 of terminal 1050 to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, and frequency offset estimation.

[0405] The control information symbols 1202 are symbols containing data such as the error correction coding method used to generate the modulated signal, information about the modulation method, information about the frame structure, information about the transmission method, etc. The base stations 470-1, 470-2, and 470-3 demodulate the modulated signal based on the information contained in the control information symbols 1202.

[0406] Information symbols 1203 are symbols used by radio equipment 453 of terminal 1050 to transmit data.

[0407] Note that radio device 453 of terminal 1050 in Fig. 27 may transmit a frame including symbols other than those shown in Fig. 17 (for example, a frame including a pilot symbol (reference symbol) in the middle of information symbol 1203). Also, the frame configuration, including the order in which symbols are transmitted, is not limited to that in Fig. 17. In Fig. 17, multiple symbols may exist in the frequency axis direction, that is, symbols may exist on multiple frequencies (multiple carriers).

[0408] The frame structure of modulated signals transmitted by base stations 470-1, 470-2, and 470-3 in Fig. 27 is the same as the frame structure in Fig. 12 described in embodiment 3. That is, as shown in Fig. 12, base stations 470-1, 470-2, and 470-3 transmit, for example, preamble 701, and then control information symbol 702 and information symbol 703.

[0409] Preamble 701 is a symbol used by radio equipment 453 of terminal 1050, which receives modulated signals transmitted by base stations 470-1, 470-2, and 470-3, to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, and frequency offset estimation.

[0410] The control information symbol 702 is a symbol containing data such as the error correction coding method used to generate the modulated signal, information about the modulation method, information about the frame structure, information about the transmission method, etc. The wireless device 453 of the terminal 1050 demodulates the modulated signal based on the information in the control information symbol 702.

[0411] Information symbols 703 are symbols used by base stations 470-1, 470-2, and 470-3 to transmit data.

[0412] Note that base stations 470-1, 470-2, 470-3 may transmit frames including symbols other than those shown in Fig. 12. For example, base stations 470-1, 470-2, 470-3 may transmit frames including pilot symbols (reference symbols) in the middle of information symbols 703. Furthermore, the frame configuration, including the order in which symbols are transmitted, is not limited to the configuration in Fig. 12. Furthermore, in Fig. 12, multiple symbols may exist in the frequency axis direction. In other words, in Fig. 12, symbols may exist on multiple frequencies (multiple carriers).

[0413] 33 is a flowchart showing an example of processing performed by "fifth device 1000," "terminal 1050," and "base station #X." X is 1, 2, or 3.

[0414] First, fifth equipment 1000 transmits a modulated signal with the frame configuration of FIG. 31 (ST2801).

[0415] Then, terminal 1050 receives the modulated signal transmitted by fifth device 1000 and selects the base station to be accessed by terminal 1050 from base station 470-1 (base station #1), base station 470-2 (base station #2), and base station 470-3 (base station #3) in FIG. 27 (ST2802).

[0416] This point will be explained below. Terminal 1050 receives a modulated signal transmitted by fifth device 1000 in order to access one of base stations 470. At this time, terminal 1050 obtains, for example, one of "frame #1 group transmission," "frame #2 group transmission," or "frame #3 group transmission" in FIG. 31 in one frame of a moving image or still image. Then, terminal 1050 determines, from the obtained base station information (for example, SSID), which base station 470 terminal 1050 will access, from base station 470-1 (base station #1), base station 470-2 (base station #2), or base station 470-3 (base station #3).

[0417] Next, terminal 1050 receives the modulated signal transmitted by fifth equipment 1000, and acquires the SSID of base station #X to be accessed by terminal 1050 (ST2803).

[0418] Additionally, terminal 1050 acquires an encryption key to be used for communication with base station #X that terminal 1050 accesses (ST2804).

[0419] Terminal 1050 then establishes connection with base station #X via radio waves (ST2805). Terminal 1050 receives a response from base station #X, and thereby completes the connection between terminal 1050 and base station #X (ST2806).

[0420] Terminal 1050 then transmits connection destination information to base station #X using radio waves (ST2807).

[0421] Base station #X obtains information to be transmitted to terminal 1050 from the network (ST2808).

[0422] Then, base station #X transmits the obtained information to terminal 1050 using radio waves, and terminal 1050 receives the information (ST2809). Terminal 1050 obtains necessary information from the network via base station #X, for example, when necessary.

[0423] As described above, based on the SSID information and encryption key information transmitted from fifth device 1000, terminal 1050 connects to base station 470 and acquires the information, thereby enabling secure acquisition of the information via base station 470, whose security is guaranteed. This is because, when information is acquired from a modulated signal of visible light, it is easy for the user to determine whether the source of the information is secure because it is visible light. In contrast, for example, when the SSID is acquired from a modulated signal of radio waves transmitted by a wireless LAN, it is difficult for the user to identify the device that transmitted the radio waves. Therefore, in terms of ensuring the security of information, visible light communication is more suitable for acquiring an SSID than wireless LAN communication.

[0424] In the present embodiment, the case where fifth device 1000 transmits encryption key information has been described. However, for example, if base station 470 is not performing encrypted communication using an encryption key, fifth device 1000 may transmit only information related to the SSID without transmitting encryption key information. In this case, the same implementation can be achieved by simply deleting the configuration related to the encryption key from the configuration described above.

[0425] Furthermore, the configuration of the fifth device is not limited to the configuration of the fifth device 1000 shown in FIG. 27, the configuration of the terminal is not limited to the configuration of the terminal 1050 shown in FIG. 27, and the connection destinations and configurations of base stations #1, #2, and #3 are not limited to the connection destinations and configurations of base stations 470-1, 470-2, and 470-3 shown in FIG. 27.

[0426] Furthermore, according to this embodiment, even if a plurality of terminals 1050 exist in a certain area, it is possible to reduce the number of terminals 1050 that have difficulty accessing base station 470.

[0427] In addition, in Figure 32, the frame structures of the modulated signals transmitted by the fifth devices 1000 placed at the positions of ``○'' 2701-1, 2701-2, 2701-3, 2701-4, 2701-5, 2701-6, 2701-7, 2701-8, 2701-8, 2701-9, and 2701-10 may all be the same as the structure in Figure 31, or the modulated signals transmitted by the fifth devices 1000 may each have a different frame structure, or there may be multiple fifth devices 1000 transmitting modulated signals with the same frame structure.

[0428] (Embodiment 8) In this embodiment, as one application example of the above-mentioned communication method using optical signals, a case where the communication method using optical signals is used in combination with image processing will be described. The communication system according to the embodiment of the present application can be applied to, for example, communication between automobiles (vehicle-to-vehicle communication) and communication between automobiles and communication equipment installed on or near roads (road-to-vehicle communication).

[0429] First, a basic configuration of this embodiment will be briefly described. However, this basic configuration is not limited to automobiles, and can also be applied to mobile terminals such as smartphones and notebook PCs, and further to other electronic devices.

[0430] 34 is a block diagram showing the configuration of a communication device A1000, which is an example of a communication device according to this embodiment. The communication device A1000 includes a light receiving device A1002, a control unit A1004, and a wireless device A1006.

[0431] The light receiving device A1002 receives an optical signal A1001 emitted from a transmitter (not shown) and / or captures still or moving images, and outputs received light data A1003. The control unit A1004 controls other devices included in the communication device A1000 and processes the received light data A1003 input from the light receiving device A1002 and the wireless received data input from the wireless device A1006. Based on a control signal A1005 from the control unit A1004, the wireless device A1006 wirelessly connects to another communication device A1100 to perform wireless communication, transmitting wirelessly transmitted data and receiving wirelessly received data. The wirelessly transmitted data and wirelessly received data are transmitted and received as wireless communication data A1008 between the wireless device A1006 and the control unit A1004. The control unit A1004 outputs a control signal A1007 for controlling the operation of the light receiving device A1002, and the light receiving device A1002 controls its operation based on the control signal A1007.

[0432] When still image data or video data is included in the received light data A1003 generated by the light receiving device A1002, the control unit A1004 may perform image processing using the still image data or video data. Details of examples of image processing performed by the control unit A1004 will be described later.

[0433] Fig. 35 is a block diagram showing the configuration of communication device A2000, which is another example of a communication device according to the present embodiment. In Fig. 35, components having the same functions as those of communication device A1000 shown in Fig. 34 are given the same reference numerals as in Fig. 34, and descriptions thereof will be omitted. Communication device A2000 differs from communication device A1000 in that it includes a presentation unit A2003 and an input unit A2004.

[0434] The control unit A1004 generates an image based on the received light data A1003 and / or wirelessly received data, other input information, information read from memory, etc., and outputs the generated image as presentation information A2002 to the presentation unit A2003. The presentation information A2002 is, for example, information including image information and text information generated based on the received light data A1003 or other data. The presentation unit A2003 may be, for example, a liquid crystal display, a plasma display, an organic light-emitting diode (EL) display, etc. that displays an image signal generated from the image information or text information obtained as the presentation information A2002, but is not limited to these. For example, the presentation information A2002 may be audio information, and the presentation unit A2003 may be a speaker that outputs audio in accordance with the audio information. The input unit A2004 outputs input information A2005, such as information indicating the user's operation or input text information, to the control unit A1004 in accordance with the user's operation. The input unit A2004 may be, for example, a touch panel, physical keys, a floating touch display, a motion sensor, etc., but is not limited to these. For example, the input unit A2004 may be a microphone, and the input information A2005 may be audio information.

[0435] Next, the detailed configuration of the light receiving device A1002 will be described.

[0436] FIG. 36 is a block diagram showing the configuration of a light receiving device A3000, which is a first example of the detailed configuration of the light receiving device A1002 according to this embodiment.

[0437] The light receiving device A3000 includes a light receiving unit A3001 and a received light signal processing unit A3003. The light receiving unit A3001 has a configuration similar to that of the light receiving unit 151 in Fig. 6, for example, and receives light incident from the outside and outputs a received light signal A3002. The received light signal processing unit A3003 performs predetermined processing on the received signal A3002 and outputs the resulting signal as received light data A1003.

[0438] The predetermined processing performed by the received light signal processing unit A3003 on the received signal A3002 includes, for example, demodulation of modulated signal components included in the received signal A3002, error correction decoding, and other processes, and outputs the demodulated data A4002 obtained by demodulation as the received light data A1003. In another example, the received light signal processing unit A3003 performs the predetermined processing by generating still image data or video data from the received signal A3002 acquired by the light receiving unit A3001, which is an image sensor such as a CMOS or organic CMOS, and outputting the generated still image data or video data as the received light data A1003. Here, the still image data or video data may be encoded data encoded using an image compression method or a video compression method, or may be uncompressed data. A detailed configuration example of the received light signal processing unit A3003 is described below.

[0439] 37 shows the configuration of the received light signal processing unit A4000, which is an example of the configuration of the received light signal processing unit A3003. The received light signal processing unit A4000 has a reception processing unit A4001. The reception processing unit A4001 performs processing such as demodulation and error correction on the received signal A3002 and outputs the resulting demodulated data A4002 as received light data A1003. The received signal A3002 input to the received light signal processing unit A4000 may be a signal acquired by an image sensor such as a CMOS sensor using a sampling method for receiving optical signals, such as the above-mentioned line scan sampling, an application example of line scan sampling, or frame sampling, or it may be a signal sampled at a sampling rate required for receiving optical signals using an element other than an image sensor, such as a photodiode, that can convert optical signals into electrical signals.

[0440] 38 shows the configuration of a received light signal processing unit A5000, which is another example of the configuration of the received light signal processing unit A3003. The received light signal processing unit A5000 has an image data generation unit A5001, and outputs image data A5002 containing optical signal information as received light data A1003. That is, the image data generation unit A5001 generates still image data or video data from the received signal A3002, and outputs the generated still image data or video data, image data A5002, as received light data A1003.

[0441] In the following description, for simplicity, unless otherwise specified, an example will be described in which the image data A5002 is video data. However, it goes without saying that the video data in the following description can be replaced with still image data, or a combination of video data and still image data, and the same implementation is possible.

[0442] When the light receiving device A1002 includes the light receiving signal processing unit A5000, the light receiving unit A3001 is an image sensor such as a CMOS sensor. The light receiving device A1002, for example, controls the operation of the light receiving unit A3001 and acquires the received signal A3002 using a sampling method for receiving an optical signal during the first period of Fig. 39, and acquires the received signal A3002 using an imaging method for capturing moving images during the second period of Fig. 39.

[0443] Hereinafter, a signal acquired using a sampling method for receiving an optical signal will be referred to as an "optical communication imaging signal," and a signal acquired using an imaging method for video shooting will be referred to as a "video imaging signal." Furthermore, data generated by the image data generation unit A5001 from an optical communication imaging signal will be referred to as "optical communication imaging data," and data generated from a video imaging signal will be referred to as "video imaging data."

[0444] Fig. 39 shows an example of a method for controlling an image sensor when one image sensor is used to acquire both an imaging signal for optical communication and an imaging signal for moving images in a time-division manner. In the light receiving device A1002, during a first period in Fig. 39, the light receiving unit A3001 acquires an imaging signal for optical communication using a sampling method for receiving optical signals, and during a second period, the light receiving unit A3001 acquires an imaging signal for moving images using an imaging method for moving image shooting.

[0445] Here, the first period and the second period are, for example, periods corresponding to one or more frames of a moving image. However, the light receiving device A1002 may switch between the sampling method for receiving an optical signal and the imaging method for capturing a moving image at a timing not synchronized with the frames of the moving image. The light receiving device A1002 may allocate the first period periodically or aperiodically. Furthermore, the rules for arranging the first period, such as the period for arranging the first period, may be dynamically changed.

[0446] The light receiving device A1002 may determine the time to start the first period and / or the time to end the first period based on a signal input from outside. For example, the light receiving device A1002 controls the operation of the light receiving unit A3001 based on a control signal A1007 input from the control unit A1004. In this case, the control unit A1004 may output a control signal for controlling the operation of the light receiving unit A3001 based on a signal received from a transmitting device external to the communication devices A1000 and A2000 using a communication method such as wireless communication, wired communication, or optical communication, or data acquired from a sensor such as an image sensor included in the communication devices A1000 and A2000.

[0447] The control information for controlling the operation of the light receiving unit A3001 may be, for example, a signal specifying a rule for arranging the first period and the second period described above, or a signal instructing the light receiving unit A3001, which normally acquires an image signal for moving images using an imaging method for moving images, to temporarily or continuously acquire an image signal for optical communication using a sampling method for receiving optical signals. Specific examples will be described later.

[0448] Although the above description has been given of an example in which the first and second periods are alternately arranged, the method of controlling the image sensor is not limited to this. For example, a third period may be arranged in which the CMOS sensor operates in an imaging or sampling method different from the methods implemented in the first and second periods, or a transition period for switching the operation of the image sensor may be included between the first and second periods.

[0449] According to the image sensor control method, it is possible to use a single image sensor to acquire both an image signal for optical communication and an image signal for video in a time-division format, thereby reducing the number of image sensors installed in the communication device.

[0450] The light receiving device A1002 may acquire the received signal A3002 by constantly operating the light receiving unit A3001 in a sampling mode for receiving an optical signal.

[0451] When generating the moving image data A5002, the image data generation unit A5001 may perform encoding processing using a moving image compression method on a moving image signal made up of multiple frames generated from the received signal A3002.

[0452] For example, if the received signal A3002 includes an imaging signal for optical communication and an imaging signal for moving image, the image data generation unit A5001 may perform moving image compression processing on frames generated from the imaging signal for moving image, excluding images (or frames) generated from the imaging signal for optical communication. In this case, the light receiving device A1002 outputs the encoded moving image data and the image data generated from the imaging signal for optical communication as received light data A1003.

[0453] In the above description, the imaging signal for optical communication is output as image data from the light receiving device A1002, but the imaging signal for optical communication may be output as data in any format from the light receiving device A1002 as long as the format is such that the optical signal can be demodulated. For example, the imaging signal may be data obtained by averaging or adding up the luminance values ​​of the pixels included in each exposure line, or data obtained by dividing each exposure line into a plurality of regions and arranging the average or sum of the luminance values ​​of the pixels included in each region in order.

[0454] Note that the video encoding process that the image data generation unit A5001 can perform when the received signal A3002 includes an imaging signal for optical communication and an imaging signal for moving images is not limited to the above-described video encoding process. For example, the image data generation unit A5001 may perform a common video compression process on a video including frames formed by imaging signals for optical communication and frames formed by imaging signals for moving images, and the light receiving device A1002 may output the encoded video data generated from the imaging signals for optical communication and the imaging signals for moving images as received light data A1003.

[0455] Next, the operation of the control unit A1004 when the light receiving device A1002 has the configuration of the received light signal processing unit A5000 will be described.

[0456] When the light receiving device A1002 includes the configuration of the received light signal processing unit A5000, the light receiving device A1002 does not perform processing such as demodulation or error correction on the imaging data for optical communication. Therefore, the control unit A1004 performs processing such as demodulation and error correction on the optical signal using the imaging data for optical communication included in the received light data A1003, and acquires the data transmitted by the optical signal.

[0457] In addition, when the received light data A1003 includes imaging data for moving images in addition to imaging data for optical communication, the control unit A1004 may perform image processing such as pattern recognition on the imaging data for moving images in addition to demodulating and correcting errors on the optical signal included in the imaging data for optical communication, and may further control the light receiving device A1002 and the wireless device A1006 based on the results of image processing such as pattern recognition.

[0458] Examples of signal processing using video imaging data include, for example, processing to detect people or body parts such as people's faces, processing to identify people, processing to detect objects such as cars or drones, processing to identify objects such as cars or drones, processing to detect the motion or movement of a detected person or object, and processing to track a detected person or object. These processes may be performed by extracting features determined according to the purpose of the signal processing from the video imaging data and using the extracted features, or may be performed using a model created by machine learning using a multi-layered neural network. Note that when using a model created by machine learning using a multi-layered neural network, the video imaging data may be preprocessed and the preprocessed data may then be input into a model created by machine learning using a multi-layered neural network.

[0459] In the above explanation, it has been stated that the control unit A1004 uses imaging data for video for signal processing, but in addition to imaging data for video, audio data or data obtained by other sensors may be used, or audio data or data obtained by other sensors may be used instead of imaging data for video.

[0460] Furthermore, when the light receiving device A1002 has the configuration of the light receiving signal processing unit A5000 and outputs encoded video data as the light receiving data A1003, the control unit A1004 may perform video decoding processing corresponding to the video encoding processing on the encoded video data included in the light receiving data A1003 as the above signal processing or as part of the signal processing.

[0461] Next, an example of the configuration of the received light signal processing unit A3003 will be described.

[0462] 40 shows the configuration of a received light signal processing unit A7000, which is a third example of the configuration of the received light signal processing unit A3003. The received light signal processing unit A7000 has a reception processing unit A7001 and an image data generation unit A7003.

[0463] The reception processing unit A7001 of the received light signal processing unit A7000 has the same function as the reception processing unit A4001 provided in the received light signal processing unit A4000 described with reference to FIG.

[0464] The image data generating section A7003 of the received light signal processing section A7000 has the same function as the image data generating section A5001 provided in the received light signal processing section A5000 described with reference to FIG.

[0465] When the light receiving device A1002 includes the light receiving signal processing unit A7000, the light receiving device A1002 controls the light receiving unit A3001 to obtain an imaging signal for moving images and an imaging signal for optical communication as a received signal A3002. The light receiving signal processing unit A7000 inputs the imaging signal for moving images to the image data generation unit A7003 and inputs the imaging signal for optical communication to the reception processing unit A7001. However, it goes without saying that the light receiving signal processing unit A7000 may also input the imaging signal for optical communication to the image data generation unit A5001.

[0466] The received light signal processing unit A7000 outputs demodulated data A7002 and video data A7004 as received light data A1003.

[0467] At this time, the demodulated data A7002 may be provided with additional information or metadata, such as time information indicating the time at which the modulated signal corresponding to the demodulated data was received. Here, the time information added to the demodulated data A7002 may be in a format that allows identification of its relationship with the time information added to the video data A7004. For example, the received light signal processing unit A7000 may add the time information of the demodulated data A7002 and the time information of the video data A7004 based on a common clock signal or timeline, or information indicating the relationship between the time information of the demodulated data A7002 and the time information of the video data A7004, such as information indicating an offset of the time information of the video data A7004 relative to the time information of the demodulated data A7002, may be included in the time information of the demodulated data A4002 or the time information of the video data A5002.

[0468] The demodulated data A7002 may also include, as additional information or metadata, position information indicating the position within the image of the transmitting device or light source that transmitted the modulated signal corresponding to the demodulated data.

[0469] The additional information of the demodulated data A7002 may include both time information and location information, or may include only one of them. Furthermore, the additional information of the demodulated data A7002 may include related information related to the demodulated data other than time information and location information.

[0470] Although the position information is described as information indicating the position of the transmitting device or light source within an image, other information may be used. For example, the position information may be information indicating an area within an image used to detect the optical signal, or information indicating a position in three-dimensional space. The position information in three-dimensional space may be, for example, information indicating the direction in which the light receiving device A1002 is capturing images and the position of the video image data within the image, or information indicating coordinate values ​​or an area in a coordinate system centered on the light receiving device or communication device, estimated from the above information. Furthermore, the position information may be information indicating coordinate values ​​or an area in any coordinate system used in GPS, a three-dimensional map, or the like, estimated using the position information of the communication device or light receiving device. Furthermore, if the light receiving device A1002 acquires not only video image data but also depth image data indicating the depth to the captured object, the position in three-dimensional space may be estimated using the depth image data in addition to the video image data.

[0471] The distance image can be acquired using, for example, a time-of-flight (TOF) method, a distance measurement method using stereo parallax, or a laser imaging detection and ranging (LIDER) method.

[0472] The demodulated data A7002 and the video data A7004 may be transmitted to the control unit A1004 of the communication device A1000 or the control unit A1004 of the communication device A2000 as multiple separate data streams or data packet sequences, or may be multiplexed into a data stream in a format that can store both the demodulated data A7002 and the video data A7004 and transmitted in a single data stream or data packet sequence to the control unit A1004 of the communication device A1000 or the control unit A1004 of the communication device A2000.

[0473] 41 shows the configuration of a light receiving device A8000, which is a second example of the configuration of the light receiving device A1002. The light receiving device A8000 includes a first light receiving unit A8001-1, a second light receiving unit A8001-2, a first light receiving signal processing unit A8003-1, and a second light receiving signal processing unit A8003-2.

[0474] The first light receiving unit A8001-1 is an image sensor such as a CCD, CMOS, or organic CMOS, and the second light receiving unit A8001-2 is an image sensor such as a CCD, CMOS, or organic CMOS, or a device capable of converting optical signals into electrical signals such as a photodiode. The light receiving device A8000 operates the first light receiving unit A8001-1 in an imaging method for capturing moving images to obtain an imaging signal for moving images as a received signal A8002-1.

[0475] If the second light receiving unit A8001-2 is an image sensor, the light receiving device A8000 operates the second light receiving unit A8001-2 using a sampling method for receiving optical signals and acquires an image pickup signal for optical communication as the received signal A8002-2. On the other hand, if the second light receiving unit A8001-2 is a device that can convert optical signals into electrical signals, such as a photodiode, the light receiving device A8000 acquires the received signal A8002-2 sampled at a sampling rate required for receiving optical signals using the second light receiving unit A8001-2.

[0476] The first received light signal processing unit A8003-1 has the same function as, for example, the received light signal processing unit A5000 shown in FIG. 38, and outputs image data A8004-1, which is imaging data for moving images, as received light data A1003.

[0477] The second received light signal processing unit A8003-2 has the same function as the received light signal processing unit A4000 shown in Fig. 37, for example, and outputs demodulated data A8004-2 as received light data A1003. The second received light signal processing unit A8003-2 has the same function as the received light signal processing unit A5000 shown in Fig. 38, and outputs image data A8004-2, which is imaging data for optical communication, as received light data A1003.

[0478] According to this configuration, the light receiving device A8000 can simultaneously acquire image data A8004-1, which is imaging data for moving images, and image data A8004-2, which is demodulated data or imaging data for optical communication, and therefore can perform both optical communication and video imaging without creating a period during which imaging data for moving images cannot be acquired.

[0479] Although the light receiving device A8000 has been described as having two sets of light receiving units and light receiving signal processing units as an example, it may also have N sets of light receiving units and light receiving signal processing units (N is an integer greater than or equal to 3).

[0480] Furthermore, the first light receiving unit A8001-1 and the second light receiving unit A8001-2 do not need to be separate elements; for example, some of the pixels of an image sensor may be operated as the first light receiving unit A8001-1 using an imaging method for video shooting and used for video shooting, and another part of the pixels of the same image sensor may be operated as the second light receiving unit A8001-2 using a sampling method for receiving optical signals and used for optical communication.

[0481] Similarly, when the light receiving device A8000 includes N or more systems of light receiving units and light receiving signal processing units, the pixels included in a first region of the image sensor may be operated in an imaging method for video shooting and used for video shooting, and the pixels included in each of the second to Nth regions of the image sensor may be operated in a sampling method for receiving optical signals and used for optical communication. Note that if video shooting and optical communication do not need to be performed simultaneously, the pixels of the image sensor may be divided into multiple regions without operating any of the pixels in the imaging method for video shooting, and the pixels in each region may be operated in a sampling method for receiving optical signals, so that multiple optical communications are performed in parallel.

[0482] When using an image sensor to capture video or perform optical communication, it is not necessary to keep all pixels operating at all times; the image sensor may include pixels that are temporarily or continuously inactive, i.e., elements that do not read out the charge accumulated by receiving light.

[0483] Next, an example of control of an image sensor when a plurality of optical signals are received simultaneously using the image sensor will be described with reference to FIG.

[0484] Fig. 42A shows a state in which four light sources AD that transmit different optical signals are included in the capture range when using an imaging method for video shooting. Each square in the capture range in Fig. 42A corresponds to one pixel.

[0485] At this time, the light receiving device A8000 determines the areas A to D that each of the light sources AD includes, as shown in (B) of Figure 42, and acquires the optical signal by operating the pixels included in each of the areas A to D using a sampling method for receiving the optical signal.

[0486] As an example of a configuration for performing sampling for receiving an optical signal for each region, a sampling method in an image sensor having a shutter function for each pixel will be described.

[0487] (Example of line scan sampling by region) As shown in FIG. 42C, a case will be described in which line scan sampling is performed in region A, where one line is formed by four pixels arranged vertically (column direction). In this case, region A is composed of five lines. The light receiving device exposes the five lines of region A with a shifted exposure period for each line, thereby acquiring changes in brightness or color of the modulated optical signal. However, the size of each region, i.e., the number of pixels in the row direction and the number of pixels in the column direction included in each region, is not limited to the example shown in FIG. 42 and may be any number. Furthermore, the size of the region where optical communication sampling is performed may be changed depending on the size, position, and relative position of each light source on the screen. In the example of FIG. 42C, one line is formed by four pixels arranged in the column direction. However, for example, one line may be formed by five pixels arranged in the row direction, and in the case of FIG. 42C, it may be considered that there are four lines in the row direction.

[0488] In area A in Fig. 42(C), the light receiving device reads out the signal of Line 1, which is the leftmost line of area A, and then sequentially reads out the signal of the line immediately to the right of the line read out immediately before. After reading out the signal of Line 5, which is the rightmost line of area A, is completed, the device returns to Line 1, the leftmost line, and repeats the process of reading out signals for each line.

[0489] The light receiving device performs line scan sampling in each of areas B to D in Figure 42 (B) by acquiring signals using the same process as for area A. Here, the light receiving device may expose the leftmost lines of all areas at the same time or at different times. Also, the lines of area A and area C located in the same column on the image sensor may be exposed for the same exposure period, and the lines of area B and area D located in the same column on the image sensor may be exposed for the same exposure period. However, areas A to D include lines that are exposed in the same exposure period.

[0490] Here, we have explained the case where multiple pixels arranged vertically (column direction) are exposed as one line for the same period and signals are read out for each line, but line scan sampling can also be performed where multiple pixels arranged horizontally (row direction) are considered as one line.

[0491] In the above description, at least one pixel included in the image sensor is used for both video shooting and optical communication, and the pixel is switched between acquiring a signal using the imaging method for video shooting and acquiring a signal using the sampling method for optical communication, but the configuration of the light receiving device including an image sensor is not limited to this. For example, the image sensor may include pixels used for optical communication in addition to pixels used for video shooting.

[0492] When the image sensor includes pixels used for optical communication in addition to pixels used for video capture, the shape or size of the pixels used for optical communication may be different from the shape or size of the pixels used for video capture.

[0493] In addition, video recording using pixels for video recording and sampling for optical communication using pixels for optical communication can be controlled independently, and in a situation where one of the processes is not required, one of the processes can be stopped and the supply of power to the circuit for acquiring the signals required for that process can be partially or completely stopped, thereby reducing power consumption.

[0494] As described above, by performing line scan sampling, it becomes possible to receive different modulated signals from multiple light sources in parallel, as shown in (A) of Figure 42, which has the effect of improving the data transmission speed.

[0495] Next, an example of the configuration of the control unit A1004 included in the communication device A1000 or the communication device A2000 will be described.

[0496] 43 is a diagram showing a control unit A10000, which is an example of the physical configuration of the control unit A1004. The control unit A10000 includes a CPU (Central Processing Unit) A10001 and a memory A10002. The memory A10002 stores programs executed by the control unit A1004 and data necessary for processing performed by the control unit. The CPU A10001 performs processing based on programs read from the memory A10002, for example, to realize the functions of the control unit A1004. The memory A10002 also stores data such as image data acquired by the receiving device and reads out the stored data.

[0497] Although the control unit A10000 has been described herein as consisting of a CPU and memory, it may also include other components. For example, it may include a GPU (Graphics Processing Unit) in addition to the CPU, or a circuit for performing image processing such as video encoding and decoding, and pattern recognition of video image data. The control unit A10000 may also include an I / O (Input / Output) that controls data transfer between the control unit A10000 and a device connected thereto, such as the wireless device A1006.

[0498] 44 is a diagram showing the configuration of a control unit A11000, which is a first example of the configuration of the control unit A1004. The control unit A11000 has a signal processing unit A11002, a wireless control unit A11004, and a light receiving device control unit A11006.

[0499] The signal processing unit A11002 acquires image data including imaging data for optical communication as received light data A1003 from the light receiving device A1002, or demodulated data that has been demodulated and error corrected as an optical signal. When the received light data A1003 is image data including imaging data for optical communication, the signal processing unit A11002 acquires a received signal corresponding to the modulated signal from the imaging data for optical communication and acquires demodulated data by performing demodulation and error correction on the received signal.

[0500] The wireless control unit A11004 outputs a control signal A1005 to the wireless device A1006 for controlling the operation of the wireless device A1006. The wireless control unit A11004 transfers wireless reception data received via the wireless device A1006 to the signal processing unit A11002, and transfers wireless transmission data to be transmitted to another communication device via the wireless device A1006 from the signal processing unit A11002 to the wireless device A1006.

[0501] The signal processing unit A11002 performs signal processing using any data such as demodulated optical communication data, video capture data, and wireless reception data acquired via the light receiving device A1002 and the wireless device A1006. Based on the results of the signal processing described above, for example, the signal processing unit A11002 instructs the wireless control unit A11004 to control the wireless device A1006 and instructs the light receiving device control unit A11006 (A11005) to control the light receiving device.

[0502] The light receiving device control unit A11006 controls the light receiving device A1002 based on instructions from the signal processing unit A11002. Examples of control over the light receiving device A1002 include control over whether the light receiving units A3001, A8001-1, and A8001-2 acquire signals using an imaging method for video capture or a sampling method for receiving optical signals, and setting a pixel area to operate using a sampling method for receiving optical signals when signals are acquired using a sampling method for receiving optical signals using a portion of the pixels of the image sensor. However, the control over the light receiving device A1002 is not limited to this. For example, the control over the light receiving device A1002 may include control over switching the power supply of the light receiving device A1002 on and off, or control over switching signal processing for received light signals performed within the light receiving device A1002. Furthermore, some of the control described here may be performed automatically based on the results of signal processing for received light signals within the light receiving device A1002.

[0503] 45 is a diagram showing the configuration of a control unit A12000, which is a second example of the configuration of the control unit A1004. The control unit A12000 differs from the control unit A11000 in that it includes an equipment control unit A12002.

[0504] The device control unit A12002 receives as input (A12001) video imaging data acquired by the signal processing unit A11002 and the processing results of the signal processing unit A11002, generates an image to be displayed on the presentation unit A2003, and outputs the generated image signal as presentation information A2002 to the presentation unit A2003. The device control unit A12002 acquires input information A2005 acquired by the input unit A2004 in response to a user's operation on the input unit A2004, and transfers it to the signal processing unit A11002.

[0505] With this configuration, the signal processing unit A11002 can perform signal processing based on input information A2005 acquired in response to user operation, in addition to demodulated optical communication data, video capture data, and wireless reception data acquired via the light receiving device A1002 and the wireless device A1006. Based on the results of the signal processing described above, for example, the signal processing unit A11002 instructs the wireless control unit A11004 to control the wireless device A1006, instructs the light receiving device control unit A11006 to control the light receiving device (A11005), and instructs the presentation unit A2003 to change the image to be displayed.

[0506] Below, as an example of processing performed by the control unit A1004, we will explain a communication control method that controls the wireless device A1006 based on demodulated data obtained by receiving an optical signal and the results of image processing such as pattern recognition performed on video imaging data.

[0507] The signal processing unit A11002 acquires moving image imaging data as received light data A1003 from the light receiving device A1002 and performs image processing such as pattern recognition on the moving image imaging data. The wireless control unit A11004 controls the wireless device A1006 based on the results of the image processing in the signal processing unit A11002.

[0508] The communication control method described in this embodiment uses demodulated data with additional information added thereto, which associates demodulated data obtained by receiving an optical signal with additional information such as positional information indicating the position on an image of the light source used to transmit the optical signal or the transmitter that transmitted the optical signal. In this embodiment, any information may be transmitted using optical communication and is not limited to the transmission of specific information. However, in the following description of this communication control method, as an example, a case will be described in which connection information including information necessary for connection or communication with other wireless communication devices, such as the SSID of the base station described in Embodiments 3 to 7, is transmitted by optical signal.

[0509] The signal processing unit A11002 performs processing using demodulated data with additional information added, which is acquired by the light receiving device A1002 or inside the signal processing unit A11002. Here, the demodulated data is connection information corresponding to other wireless communication devices. When multiple pieces of connection information are acquired, the signal processing unit A11002 controls communication processing performed by the wireless device A1006 using the additional information corresponding to each piece of connection information and the results of image processing such as pattern recognition.

[0510] A first example of communication control based on the result of image processing will be described below.

[0511] In a first example of communication control based on the results of image processing, communication devices A1000 and A2000 are vehicles or devices mounted on the vehicles, and a camera mounted on the vehicle is used as light receiving device A1002. Fig. 46 is a schematic diagram showing an example of an image captured by a camera that captures the area ahead of the vehicle. Fig. 46 shows three other vehicles A13001, A13002, and A13003 traveling ahead of the vehicles corresponding to communication devices A1000 and A2000.

[0512] In this embodiment, an example will be described in which a camera is used to take pictures of the front of the vehicle, but it goes without saying that the present invention can also be applied to cameras that take pictures of the rear or side of the vehicle.

[0513] Here, the other cars A13001, A13002, and A13003 each include a light source such as an LED and a transmitter 102 that transmits optical signals using the light source. Any light source provided in the car, such as a headlight or taillight, can be used as the light source for optical communication, and which of the multiple light sources provided in the car is used to transmit optical signals can be designed as desired depending on the use form of the optical communication. Furthermore, when multiple light sources provided in the car are used to transmit optical signals, the car may include a transmitter for optical communication for each of the multiple light sources, or one transmitter may transmit optical signals using multiple light sources. Note that the car may also include a light source for optical communication separate from the headlights and taillights.

[0514] The other vehicles A13001, A13002, and A13003 are equipped with a transmitter 102 for optical communication and a light source, as well as a communication device for wireless communication that corresponds to the other communication device A1100 described in Figures 34 and 35. If the vehicle itself and the other vehicles A13001, A13002, and A13003 have the functions of transmitting and receiving optical signals and wireless communication, each vehicle will be configured to have a transmitter 102 for optical communication and a light source 104 in the communication device A1000, A2000. In this case, the control unit A1004 may control the data transmitted by the transmitter 102.

[0515] In a first example of communication control based on the results of image processing, other vehicles A13001, A13002, and A13003 transmit connection information that can be used to connect to the communication device equipped in each vehicle via optical communication. Below, we will explain a case where the connection information includes information indicating the SSID and the frequency channel used for communication when the communication device equipped in each vehicle operates as a base station.

[0516] In the above description, an example was described in which an SSID was notified as an identifier for determining a communication partner included in the connection information. However, the identifier information included in the connection information is not limited to an SSID. For example, it may be a physical address such as a Media Access Control (MAC) address of another communication device, or a logical address such as an Internet Protocol (IP) address of another communication device. If the identifier information is used not to select another communication device with which a communication device will directly communicate, but to select a resource to be accessed via a network such as the Internet, it may be an address of a server with which communication will be performed via a network such as the Internet, or a Uniform Resource Locator (URL), Uniform Resource Name (URN), or Uniform Resource Identifier (URI) used to identify a resource on the Internet. The identifier information included in the connection information may be any information that can identify another communication terminal or a resource on the Internet to be accessed.

[0517] In the above description, the case where the connection information notifies information about the frequency channel being used has been described, but the connection information does not have to include information about the frequency channel being used, or may include other information. Examples of other information that can be used as connection information include information about encryption keys, types of supported physical layer transmission method standards, supported data formats and communication protocols, etc.

[0518] 47 is a diagram schematically illustrating connection information obtained by the light receiving device A1002 or the control unit A1004 of the communication devices A1000 and A2000 by demodulating optical signals transmitted using light sources by the transmission units of the other vehicles A13001, A13002, and A13003. The communication devices A1000 and A2000 obtain connection information from the optical signal transmitted by the other vehicle A13001 that the SSID is "XXX" and the frequency channel in use is "1," obtain connection information from the optical signal transmitted by the other vehicle A13002 that the SSID is "YYY" and the frequency channel in use is "3," and obtain connection information from the optical signal transmitted by the other vehicle A13003 that the SSID is "ZZZ" and the frequency channel in use is "3."

[0519] Some of this connection information can be substituted by information that can be acquired by the radio device A1006 included in the communication devices A1000 and A2000 performing carrier sensing for a certain period of time and receiving signals transmitted from each of multiple other communication devices. However, it is difficult for the communication devices A1000 and A2000 to identify which of multiple other communication devices present in the vicinity transmitted these signals, and there is a possibility that the communication devices A1000 and A2000 will connect to and communicate with a communication device other than the other communication device with which they actually want to communicate.

[0520] Therefore, in a first example of communication control based on the results of image processing, the control unit A1004 of the communication devices A1000 and A2000 performs image processing on video image data captured by the light receiving device A1002, and detects other vehicles A13001, A13002, and A13003 from the image shown in FIG. 46, for example. Based on the positions of the light sources of the three received optical signals, the control unit A1004 associates each of the other vehicles A13001, A13002, and A13003 detected from the image with the three pieces of connection information received via optical communication. This allows the control unit A1004 to identify the connection information to use when wirelessly communicating with each of the three vehicles detected from the image.

[0521] Next, the control unit A1004 determines the relative positions of the other vehicles A13001, A13002, and A13003 from the image, as well as the relative positions of each vehicle and the vehicle itself, and selects a vehicle for wireless communication. For example, the control unit A1004 may select the vehicle A13003 that is closest to the vehicle itself as the communication target. The control unit A1004 may also determine the lane in which each vehicle is traveling, and select the vehicle A13001 that is traveling in the lane in which the vehicle itself is traveling and that is located furthest in the image as the communication partner.

[0522] This configuration makes it possible to associate information that is difficult to associate with devices in real space using only wireless communication, such as identifiers such as SSIDs and addresses in wireless communication, with objects detected by signal processing such as pattern recognition from sensing data obtained by a sensor, such as an image acquired by an image sensor.As a result, for example, when acquiring information such as the surrounding environment and the movements of surrounding vehicles for the purpose of controlling autonomous driving including driving assistance, it becomes easier to connect to an appropriate communication partner as a source of information.

[0523] Next, a second example of communication control based on the result of image processing will be described.

[0524] In the second example of communication control based on the result of image processing, the configuration of the communication device A1000, A2000 or the host vehicle equipped with the communication device A1000, A2000 and the configurations of the other vehicles A13001, A13002 are the same as those in the first example of communication control based on the result of image processing. The second example of communication control based on the result of image processing differs from the first example of communication control based on the result of image processing in that another vehicle A15003 that does not have the function of transmitting an optical signal is traveling in place of the other vehicle A13003.

[0525] Fig. 48 is a diagram showing an example of an image captured by a camera capturing an image of the area in front of a vehicle in the second example of communication control based on the results of image processing. In Fig. 48, three other vehicles A13001, A13002, and A15003 are captured traveling in front of the vehicles corresponding to communication devices A1000 and A2000.

[0526] 49 is a diagram showing connection information obtained by demodulating optical signals transmitted by the light sources of the transmitters of the other vehicles A13001 and A13002 using light sources in the light receiving device A1002 or the control unit A1004 of the communication devices A1000 and A2000. The communication devices A1000 and A2000 obtain connection information from the optical signal transmitted by the other vehicle A13001, indicating that the SSID is "XXX" and the frequency channel used is "1," and from the optical signal transmitted by the other vehicle A13002, indicating that the SSID is "YYY" and the frequency channel used is "3." At this time, the communication devices A1000 and A2000 cannot obtain connection information about the other vehicle A15003 because the other vehicle A15003 does not have the function of transmitting optical signals.

[0527] In a second example of communication control based on the results of image processing, the control unit A1004 of the communication devices A1000 and A2000 performs image processing on video image data captured by the light receiving device A1002 to detect other vehicles A13001, A13002, and A15003 from the image shown in FIG. 48, for example. Based on the positions of the light sources of the two received optical signals, the control unit A1004 associates the two pieces of connection information received via optical communication with the other vehicles A13001 and A13002 among the other vehicles A13001, A13002, and A15003 detected in the image. This allows the control unit A1004 to identify the connection information to be used when communicating wirelessly with the other vehicles A13001 and A13002 detected in the image, and also identifies that the base station or communication device with the SSID "XXX" or "YYY" is not the SSID used to communicate with the other vehicle A15003.

[0528] First, a case will be described in which the other car A15003 does not have the function of transmitting an optical signal, but has the function of performing wireless communication using an SSID called "PPP."

[0529] At this time, the wireless device A1006 detects three SSIDs, "XXX," "YYY," and "PPP," as the SSIDs of other communication devices installed in vehicles within communication distance by performing carrier sensing, and the control unit A1004 determines that "PPP," which is different from the SSIDs "XXX" and "YYY" included in the connection information received as an optical signal, is the SSID to be used for communication with the other vehicle A15003, and associates the other vehicle A15003 with the SSID "PPP."

[0530] The control unit A1004 determines the relative positions of the other vehicles A13001, A13002, and A15003 from the image, as well as the relative positions of each vehicle and the vehicle itself, and selects a vehicle for wireless communication. The control unit A1004 may, for example, select the vehicle A15003 that is closest to the vehicle itself as the communication target. The control unit A1004 may also determine the lane in which each vehicle is traveling, and select the vehicle A13001 that is traveling in the lane in which the vehicle itself is traveling and that is located furthest in the image as the communication partner.

[0531] This configuration makes it possible to associate information that is difficult to associate with devices in real space using only wireless communication, such as identifiers such as SSIDs and addresses in wireless communication, with objects detected by signal processing such as pattern recognition from sensing data obtained by a sensor, such as an image acquired by an image sensor.As a result, for example, when acquiring information such as the surrounding environment and the movements of surrounding vehicles for the purpose of controlling autonomous driving including driving assistance, it becomes easier to connect to an appropriate communication partner as a source of information.

[0532] Next, a case will be described in which the other vehicle A15003 does not have both the function of transmitting an optical signal and the function of performing wireless communication.

[0533] At this time, the wireless device A1006 performs carrier sensing and detects two SSIDs, "XXX" and "YYY," as SSIDs of other communication devices installed in vehicles within communication distance. Because the control unit A1004 does not detect any SSIDs different from "XXX" and "YYY," which are SSIDs included in the connection information received as an optical signal, as SSIDs of other communication devices installed in the vehicle, the control unit A1004 determines that the other vehicle A15003 does not have the function to perform wireless communication or is not in a relationship where wireless communication is possible.

[0534] The control unit A1004 determines the relative positions of the other vehicles A13001, A13002, and A15003 from the image, as well as the relative positions of each vehicle and the subject vehicle, and selects either the other vehicle A13001 or the other vehicle A13002 as the target for wireless communication. For example, the control unit A1004 may select the other vehicle A13002 with which communication is possible that is closest to the subject vehicle as the target for communication. The control unit A1004 may also determine the lane in which each vehicle is traveling, and select the other vehicle A13001 that is traveling in the lane in which the subject vehicle is traveling and is located furthest in the image as the communication partner.

[0535] According to this configuration, it is possible to associate information that is difficult to associate with devices in real space using only wireless communication, such as identifiers such as SSIDs and addresses in wireless communication, with objects detected by signal processing such as pattern recognition from sensing data obtained by a sensor, such as an image acquired by an image sensor. As a result, it is possible to determine that information cannot be acquired through communication from another vehicle A15003 traveling immediately ahead, and when performing control of autonomous driving including driving assistance, it is possible to prevent other vehicles A13001 and A13002 with which communication is possible from being mistaken for other vehicles A15003, thereby facilitating the provision of appropriate autonomous driving control.

[0536] Next, a third example of communication control based on the result of image processing will be described.

[0537] In the third example of communication control based on the result of image processing, the configuration of the communication device A1000, A2000 or the host vehicle equipped with the communication device A1000, A2000 and the configuration of the other vehicles A13002, A13003 are the same as those in the first example of communication control based on the result of image processing. The third example of communication control based on the result of image processing differs from the first example of communication control based on the result of image processing in that a police vehicle A17001 is traveling instead of the other vehicle A13001. Although the police vehicle A17001 differs from the other vehicle A13001 in that it is a police vehicle, it has the same configuration as the other vehicle A13001 and has the functions of transmitting optical signals and wireless communication.

[0538] Fig. 50 is a diagram showing an example of an image captured by a camera capturing an image of the area in front of a vehicle in the third example of communication control based on the results of image processing. In Fig. 50, other vehicles A13002 and A13003 and a police vehicle A17001 traveling in front of the vehicles corresponding to communication devices A1000 and A2000 are captured.

[0539] 51 is a diagram schematically illustrating connection information obtained by the light receiving device A1002 or the control unit A1004 of the communication devices A1000 and A2000 by demodulating optical signals transmitted using light sources by the transmission units of the other vehicles A17001, A13002, and A13003. The communication devices A1000 and A2000 obtain connection information from the optical signal transmitted by the police vehicle A17001 that the SSID is "QQQ" and the frequency channel in use is "1," obtain connection information from the optical signal transmitted by the other vehicle A13002 that the SSID is "YYY" and the frequency channel in use is "3," and obtain connection information from the optical signal transmitted by the other vehicle A13003 that the SSID is "ZZZ" and the frequency channel in use is "3."

[0540] In a third example of communication control based on the results of image processing, the control unit A1004 of the communication devices A1000 and A2000 performs image processing on video image data captured by the light receiving device A1002, detecting the police vehicle A17001 and other vehicles A13002 and A13003 from the image shown in FIG. 50, for example. Based on the positions of the light sources of the three received optical signals, the control unit A1004 associates the three pieces of connection information received via optical communication with the police vehicle A17001 and other vehicles A13002 and A13003 detected in the image. This allows the control unit A1004 to identify the connection information to be used when performing wireless communication for the police vehicle A17001 and other vehicles A13002 and A13002 detected in the image.

[0541] The control unit A1004 performs detailed classification of the three vehicles recognized in the image processing, such as whether they are police vehicles or not, using information such as the vehicle's appearance, and recognizes that the vehicle A17001 is a police vehicle. The control unit A1004 selects the police vehicle A17001, which has a high priority for obtaining information, as the target for wireless communication from among the police vehicle A17001 and the other vehicles A13002 and A13003.

[0542] According to this configuration, when recognizing an object using signal processing such as pattern recognition from sensing data obtained by a sensor, such as an image captured by an image sensor, the recognized object can be classified in more detail and communication control can be performed based on that classification.

[0543] Note that the control of selecting a police vehicle as a communication partner with high priority for information acquisition described above is merely one example, and different control may be performed when a police vehicle is recognized. For example, police vehicle A17001 may transmit an optical signal including an identifier for identifying the police vehicle, and the control unit A1004 may acquire information about police vehicle A17001 by specifying the identifier received in the optical signal from police vehicle A17001 to another vehicle A13002 or another vehicle A13003, rather than directly connecting wirelessly to the police vehicle.

[0544] Furthermore, when a police vehicle is detected by image processing, rather than always performing the same communication control, communication control may be performed that prioritizes collecting information about the police vehicle when it is recognized that the warning lights of the recognized police vehicle are on, or when the communication devices A1000 and A2000 are equipped with a microphone as a sensor other than an image sensor and the control unit A1004 detects a siren sound by performing pattern recognition signal processing on audio data acquired by the microphone.

[0545] In addition, when detecting sounds generated by other devices using audio data acquired by a microphone, a modulated signal generated based on transmission data such as an identifier of the other device may be transmitted at the same time.

[0546] This configuration makes it possible to associate the device that generated the sound recognized by signal processing such as pattern recognition with the transmission data, such as the identifier transmitted as the sound signal. As a result, for example, in an environment where there are multiple devices with known identifiers, it may be possible to easily identify the device that generated the detected sound.

[0547] Note that sound signals may be used instead of optical signals, in which case the light receiving device A1002 in the communication devices A1000 and A2000 is replaced with a sound detection device such as a microphone. Furthermore, by using a device that can identify the direction from which sound is coming, such as an array microphone, as the sound detection device, it is possible to more accurately associate the device that generated the sound to be detected with the sound signal.

[0548] Note that the communication devices A1000 and A2000 according to the present embodiment may include multiple radio devices. For example, the communication devices A1000 and A2000 may include multiple radio devices that support communication methods defined by different standards, or multiple radio devices that support the same communication method.

[0549] Furthermore, when the communication devices A1000 and A2000 according to the present embodiment are vehicles or are communication devices mounted on vehicles, the light receiving device A1002 may be, for example, a camera included in a drive recorder, a camera for a rearview monitor, a camera for checking the vehicle's surroundings, or a camera used to display images on a monitor in place of side mirrors. In this way, by receiving optical signals using a camera mounted for purposes other than optical communication, the communication control disclosed in the present embodiment can be achieved without adding a new camera, thereby reducing costs and promoting the widespread use of optical signal receiving functions. Furthermore, since such cameras are installed so as to capture areas necessary for the driver, i.e., areas from which important information for operating the vehicle can be obtained, by combining signal processing such as image recognition with wireless communication to collect more information, it is possible to provide appropriate autonomous driving control and promote the provision of information to the driver.

[0550] This disclosure describes aspects of a method and apparatus for demodulating a transmission signal transmitted using a communication method that can be received by a sensor, such as an image sensor or a microphone, using sensing data obtained by the sensor.

[0551] In the above aspect, further, according to an aspect in which signal processing of pattern recognition such as image recognition is performed on sensing data obtained by a sensor, it becomes possible to determine the correspondence between an object in real space detected or recognized from the sensing data and the source of the transmission signal.

[0552] In the above-described aspect, further, according to an aspect in which information such as an SSID, an address, an identifier, etc. used in processing via a network including communication is transmitted using a transmission signal, it is possible to easily associate information used in processing via a network including communication with an object in real space. In other words, information used in processing via a network, which has conventionally been difficult to associate with an object in real space, can be used based on sensing data obtained from the real space.

[0553] In the above aspect, further, according to an aspect in which an image sensor is used as the sensor and information used in processing via a network including communication is transmitted as an optical signal, the reliability of the correspondence between visible objects and information used in processing via a network including communication can be improved.

[0554] In the above-described embodiment, an identifier used for communication, such as an SSID or an address, is transmitted as an optical signal, and the identifier of the target to be connected via communication is selected based on the result of image recognition signal processing. This enables communication control based on the positional relationship of the target in real space and the attributes of the target, and enables communication by specifying the target to be connected, and allows information to be acquired and control instructions to be given. As a result, for example, it becomes possible to provide a means for realizing communication with an appropriate communication partner in an environment where an unspecified number of devices are within the communication range, thereby promoting the creation and spread of new services via communication.

[0555] The eighth embodiment of the present disclosure has been described above.

[0556] Although the configuration of FIG. 5 has been described as an example of a communication system that performs visible light communication, the configuration of a communication system that performs visible light communication is not limited to the configuration shown in FIG. 5. For example, a configuration as shown in FIG. 52 may be used (see, for example, "IEEE 802.11-16 / 1499r1"). In FIG. 52, a transmission signal is transmitted as an optical signal in the baseband without being upconverted. That is, a device that transmits an optical signal of this embodiment (i.e., a device equipped with a light source) may have the transmitting-side configuration shown in FIG. 52, and a terminal that receives the optical signal of this embodiment may have the receiving-side configuration shown in FIG. 52.

[0557] (Embodiment 9) In this embodiment, supplementary explanation will be given regarding FIG.

[0558] A specific description will be given of Fig. 52. The symbol mapping unit receives transmission data, performs mapping based on the modulation method, and outputs a symbol sequence (ci).

[0559] The pre-equalization processing unit receives a symbol sequence as input, performs pre-equalization processing on the symbol sequence in order to reduce the equalization processing on the receiving side, and outputs the pre-equalized symbol sequence.

[0560] The Hermitian symmetry processing unit receives the pre-equalization processed symbol sequence as input, performs subcarrier allocation for the pre-equalization processed symbol sequence so as to ensure Hermitian symmetry, and outputs parallel signals.

[0561] The inverse (fast) Fourier transform unit receives parallel signals as input, performs an inverse (fast) Fourier transform on the parallel signals, and outputs the signals after the inverse (fast) Fourier transform.

[0562] The parallel-to-serial and cyclic prefix adding unit receives the signal after inverse (fast) Fourier transform, performs parallel-to-serial conversion, adds a cyclic prefix, and outputs the signal after signal processing.

[0563] The digital-analog conversion unit receives the processed signal as input, performs digital-analog conversion, and outputs an analog signal, which is output as light from one or more LEDs, for example.

[0564] The equalization pre-processing unit and the Hermitian symmetry processing unit may not be necessary, that is, there may be cases where signal processing is not performed in the equalization pre-processing unit and the Hermitian symmetry processing unit.

[0565] The photodiode receives light as an input, and a TIA (Transimpedance Amplifier) ​​generates a received signal.

[0566] The analog-to-digital converter performs analog-to-digital conversion on the received signal and outputs a digital signal.

[0567] The cyclic prefix removal and serial-to-parallel conversion unit receives a digital signal as input, removes the cyclic prefix, then performs serial-to-parallel conversion, and receives a parallel signal as input.

[0568] The (fast) Fourier transform unit receives parallel signals as input, performs (fast) Fourier transform on them, and outputs the (fast) Fourier transformed signals.

[0569] The detection unit receives the Fourier transformed signal as input, performs detection, and outputs a received symbol sequence.

[0570] The symbol demapper receives a received symbol sequence as input, performs demapping, and obtains a received data sequence.

[0571] As described above, even if a transmitting device that transmits an optically modulated signal and a receiving device that receives an optically modulated signal are applied to each of the embodiments in this specification, each of the embodiments can be implemented in the same manner.

[0572] (Embodiment 10) In the eighth embodiment, an example in which a transmitting device transmits a plurality of optically modulated signals and a receiving device receives a plurality of optically modulated signals has been described with reference to Fig. 42. In the present embodiment, an example in this case will be described.

[0573] Figure 53 shows an example of the configuration of a transmitting device and a receiving device in this embodiment. In Figure 53, transmitting device 100 transmits a plurality of optically modulated signals, and receiving device 150 receives a plurality of optically modulated signals to obtain received data. In Figure 53, components that operate in the same way as in Figure 6 are assigned the same numbers.

[0574] The transmitting device in Fig. 53 transmits M optical modulated signals, where M is an integer of 2 or greater.

[0575] The transmitter A2002_i receives the data A2001_i and the control signal A2005 as input, and performs error correction coding and signal processing based on the information on the error correction coding method and the information on the transmission method included in the control signal A2005, thereby generating and outputting an optically modulated signal A2003_i, where i is an integer between 1 and M.

[0576] The optically modulated signal A2003_i is then transmitted from the light source A2004_i.

[0577] The light receiving unit A2051, such as an image sensor, receives light corresponding to the optically modulated signal A2003_i. At this time, the light receiving unit A2051 receives light corresponding to M optically modulated signals. The method for receiving a plurality of optical reception signals in the light receiving unit A2051 is as described in the eighth embodiment, for example.

[0578] The light receiving unit A2051 outputs an optical reception signal A2052_i corresponding to the optical modulated signal 2003_i, where i is an integer between 1 and M inclusive.

[0579] The receiver A2053_i receives an optical reception signal A2052_i corresponding to the optical modulation signal A2003_i, performs processing such as demodulation and error correction decoding, and outputs reception data A2054_i corresponding to the data A2001_i.

[0580] The data acquisition unit A2055 receives data A2054_1, data A2054_2, . . . , data A2054_M as input, and generates and outputs data A2056.

[0581] Figure 54 shows an example of the configuration of a transmitting device and a receiving device according to this embodiment, which is different from that of Figure 53. In Figure 54, components that operate in the same way as in Figure 53 are given the same numbers.

[0582] The distribution unit A2102 receives the information A2101 and the control signal A2005 as input, performs error correction coding on the information A2101 based on information relating to the error correction coding method included in the control signal A2005, and generates error correction coded data. The distribution unit A2102 then distributes the error correction coded data and outputs error correction coded data A2001_i.

[0583] Note that the distribution to the M pieces of error-correction-coded data A2001_i may be performed in any manner. For example, the error-correction-coded data may be divided into M pieces, and each of the M divided data sequences may be assigned to the error-correction-coded data A2001_i. Alternatively, M data sequences consisting of the same data may be generated from the error-correction-coded data, and each data sequence may be assigned to the error-correction-coded data A2001_i. The method of assignment to the error-correction-coded data A2001_i is not limited to these, and it is also possible to generate M data sequences from the error-correction-coded data, and assign each data sequence to the error-correction-coded data A2001_i.

[0584] The transmitter A2002_i receives the data A2001_i and the control signal A2005 as input, performs signal processing based on the transmission method in accordance with the information on the transmission method included in the control signal A2005, and generates and outputs the optically modulated signal A2003_i, where i is an integer between 1 and M.

[0585] The optically modulated signal A2003_i is then transmitted from the light source A2004_i.

[0586] The light receiving unit A2051, such as an image sensor, receives light corresponding to the optically modulated signal A2003_i. At this time, the light receiving unit A2051 receives light corresponding to M optically modulated signals. The method for receiving a plurality of optical reception signals in the light receiving unit A2051 is as described in the eighth embodiment, for example.

[0587] The light receiving unit A2051 outputs an optical reception signal A2052_i corresponding to the optical modulated signal 2003_i, where i is an integer between 1 and M inclusive.

[0588] The receiver A2053_i receives an optical reception signal A2052_i corresponding to the optical modulated signal A2003_i, performs processing such as demodulation, and outputs reception data (log-likelihood ratio) 2054_i corresponding to the data A2001_i.

[0589] The error correction decoding unit A2151 receives received data (log likelihood ratio) 2054_1, received data (log likelihood ratio) 2054_2, ..., received data (log likelihood ratio) 2054_M as input, performs error correction decoding, and outputs received data A2152.

[0590] FIG. 55 shows an example of a frame structure of an optically modulated signal transmitted by the transmitting device 100 in FIGS.

[0591] The frame structure A2201_1 in Fig. 55 shows an example of the frame structure of the optically modulated signal A2003_1 in Fig. 53 and Fig. 54. In the frame structure A2201_1, the horizontal axis represents time.

[0592] Therefore, frame structure A2201_i in FIG. 55 shows an example of the frame structure of optically modulated signal A2003_i in FIGS. 53 and 54. In frame structure A2201_i, the horizontal axis represents time, and i is an integer between 1 and M. (That is, FIG. 55 shows M frame structures.)

[0593] As shown in frame structure A2201_i, transmitting apparatus 100 in FIGS. 53 and 54 transmits preambles A2210_i, control information symbols A2211_i, and data symbols A2212_i in optical modulated signals A2003_i.

[0594] Fig. 56 shows an example of the reception state in the receiving device 150. In the following example, it is assumed that the transmitting device 100 in Figs. 53 and 54 has 16 (M=16) light sources.

[0595] In Fig. 56, A2300 denotes an image sensor, which is an example of a light receiving unit, and A2301_1 denotes light emitted from a first light source, which includes a first optical modulation signal. Note that the first optical modulation signal corresponds to A2201_1 in Fig. 55.

[0596] Therefore, in Fig. 56, A2301_i is light emitted by the ith light source, and this light contains the ith optical modulation signal. Note that the ith optical modulation signal corresponds to A2201_i in Fig. 55. Note that i is an integer between 1 and 16.

[0597] In the example of the receiving state of the receiving device 150 in Figure 56, the light receiving unit of the receiving device 150 receives light from a fourth light source including a fourth optical modulation signal, light from an eighth light source including an eighth optical modulation signal, and light from a twelfth light source including a twelfth optical modulation signal.

[0598] For example, if the transmitting device 100 in Figures 53 and 54 transmits 16 optically modulated signals from 16 light sources, in the state shown in Figure 56, the receiving device 150 in Figures 53 and 54 will not be able to receive all 16 optically modulated signals, making it difficult to obtain correct received data. A method for overcoming this problem will be described below.

[0599] Fig. 57 shows an example of the preamble A2210_i, information included in the control information symbol A2211_i, and symbol configuration of the frame structure A2201_i of the optical modulated signal A2003_i in Fig. 55. Note that i is an integer between 1 and M (=16).

[0600] The preamble A2210_i and control information symbol A2211_i in the frame structure A2201_i include, as shown in FIG. 57, a symbol A2401 for signal detection, a symbol A2402 for synchronization, a symbol A2403 containing information regarding the number of optical modulation signals being transmitted, and a symbol A2404 containing information regarding the error correction coding method, transmission method, and modulation method.

[0601] The symbol A2401 for signal detection is a symbol that allows the receiving device 150 to know the presence of an optically modulated signal, and by detecting this symbol, the receiving device 150 knows that an optically modulated signal is present.

[0602] The synchronization symbol A2402 is a symbol used by the receiving device 150 to perform time synchronization (which may include frequency synchronization).By using this symbol, the receiving device 150 can perform time synchronization, enabling high-precision demodulation of each symbol.

[0603] Symbol A2403 containing information regarding the number of optically modulated signals being transmitted is a symbol for notifying the number of optically modulated signals being transmitted by transmitting device 100, and in the state of Figure 56, symbol A2403 containing information regarding the number of optically modulated signals being transmitted transmits the information "16".

[0604] In the receiving state of Fig. 56, the receiving device 150 receives symbol A2403 including information about the number of optically modulated signals being transmitted, thereby learning that "16" optically modulated signals are being transmitted by the transmitting device 100. In the receiving state of Fig. 56, the receiving device 150 learns that only three of the 16 optically modulated signals have been received.

[0605] Symbol A2404 containing information regarding the error correction coding method, transmission method, and modulation method is, for example, a symbol containing information regarding the error correction coding method, transmission method, and modulation method used in the data symbol (symbol for transmitting data) of optically modulated signal A2003_i, and by receiving this symbol, receiving device 150 can know the error correction coding method, transmission method, and modulation method used in optically modulated signal A2003_i.

[0606] In the case of the frame configuration of Fig. 55, transmitting device 100 transmits the symbols shown in Fig. 57 for optical modulated signals A2003_1 to A2003_16. In this way, even when receiving device 150 is not able to receive all optical modulated signals as shown in Fig. 56, it is possible to know the number of optical modulated signals being transmitted by transmitting device 100, and thereby receiving device 150 can know "whether all optical modulated signals have been received or not." If not all optical modulated signals have been received, signal processing is stopped midway, which has the effect of reducing unnecessary power consumption.

[0607] Figure 58 shows an example of the information and symbol configuration included in the preamble A2210_i and control information symbol A2211_i of the frame configuration A2201_i of the optical modulated signal A2003_i in Figure 55, which is different from Figure 57. Note that i is an integer between 1 and M (= 16), and in Figure 58, the same numbers are used for elements that operate in the same way as in Figure 57, and as they have already been explained, their explanation will be omitted.

[0608] 58, compared to FIG. 57, symbol A2501 including information regarding the number of the optical modulation signal is added as a symbol transmitted by transmitting device 100.

[0609] Figure 58 shows the frame structure A2201_i of the optical modulated signal A2003_i in Figure 55, that is, the frame structure of the i-th optical modulated signal, so the symbol A2501 containing information regarding the number of the optical modulated signal contains the information "i".

[0610] For example, symbol A2501, which includes information relating to the number of the optically modulated signal transmitted by transmitting device 100 as the first optically modulated signal, includes the information "1."

[0611] 56, the receiving device 150 receives symbol A2403 including information about the number of optical modulated signals being transmitted, thereby knowing that the transmitting device 100 is transmitting "16" optical modulated signals. Then, the receiving device 150 receives "symbol A2501 including information about the optical modulated signal number" included in the fourth optical modulated signal, "symbol A2501A including information about the optical modulated signal number" included in the eighth modulated signal, and "symbol A2501A including information about the optical modulated signal number" included in the twelfth modulated signal, and therefore knows that the fourth optical modulated signal, the eighth optical modulated signal, and the twelfth optical modulated signal have been received. By knowing this situation, the receiving device 150 performs an operation to improve the reception situation, thereby improving the data reception quality; the detailed operation will be described later.

[0612] Another example of the receiving state in receiving device 150 is shown in Figures 59 and 60. In Figures 59 and 60, the same numbers are used for components that operate in the same way as in Figure 56, and since they have already been explained, their explanation will be omitted.

[0613] In the example of the receiving state of the receiving device 150 in Fig. 59, the light receiving unit A2300 of the receiving device 150 receives light from the first light source including the first optical modulation signal to light from the 16th light source including the 16th optical modulation signal, that is, 16 optical modulation signals. In the case of Fig. 59, for example, the first optical modulation signal is received at the upper left of the light receiving unit A2300.

[0614] In the example of the receiving state in the receiving device 150 in Fig. 60, the light receiving unit A2300 of the receiving device 150 receives light from the first light source including the first optical modulation signal to light from the 16th light source including the 16th optical modulation signal, that is, 16 optical modulation signals. In the case of Fig. 60, for example, the first optical modulation signal is received at the lower right of the light receiving unit A2300, which is different from Fig. 59.

[0615] The reception states in Figures 59 and 60 are merely examples, and the circumstances under which the receiving device 150 receives the first to sixteenth optical modulated signals will differ depending on the environment. Taking this into consideration, because each optical modulated signal has a "symbol A2501 containing information about the optical modulated signal number" as shown in Figure 58, the receiving device 150 can determine "which optical modulated signal was received at which part of the light receiving unit." Then, when the receiving device 150 obtains the ith received data obtained from the received signal of the ith optical modulated signal and needs to rearrange the first to sixteenth received data, it can identify "which optical modulated signal the received data belongs to" from the "symbol A2501 containing information about the optical modulated signal number," making it possible to correctly rearrange the received data, thereby improving the data reception quality.

[0616] Next, a method of constructing a frame that is different from the above will be described.

[0617] FIG. 55 shows an example of the frame structure of an optically modulated signal transmitted by the transmitting device 100 in FIGS. 53 and 54, and as it has already been explained, the explanation will be omitted.

[0618] For example, the configuration of the preamble and control information symbols in frame structure A2201_1 in optical modulated signal A2003_1 in FIG. 55 is shown in FIG. 57, and the configuration of the preamble and control information symbols from "frame structure A2201_2 in optical modulated signal A2003_2" to "frame structure A2201_16 in optical modulated signal A2003_16" is shown in FIG. 61. Note that in FIG. 61, components that operate in the same way as in FIG. 57 are assigned the same numbers, and a distinctive feature of FIG. 61 is that it does not include "symbol A2403 including information regarding the number of optical modulated signals being transmitted." In other words, transmitting device 100 transmits "symbol A2403 including information regarding the number of optical modulated signals being transmitted" only by optical modulated signal A2003_1.

[0619] At this time, in the receiving state of the receiving device 150 in Fig. 56, the receiving device 150 does not obtain "symbol A2403 including information about the number of optical modulated signals being transmitted," and therefore is unable to grasp the number of optical modulated signals transmitted by the transmitting device 100. In this case, the receiving device 150 determines that it is difficult to receive the data correctly, and stops signal processing of the receiving operation, thereby reducing unnecessary power consumption.

[0620] In the explanation of this example, it is explained that "the transmitting device 100 transmits 'symbol A2403 including information regarding the number of optically modulated signals being transmitted' using only optically modulated signal A2003_1," but this example is not limited thereto, and the same effect as described above can be obtained if "the transmitting device 100 transmits 'symbol A2403 including information regarding the number of optically modulated signals being transmitted' using some of the optically modulated signals A2003_1 to A2003_16."

[0621] Furthermore, another example will be described.

[0622] FIG. 55 shows an example of the frame structure of an optically modulated signal transmitted by the transmitting device 100 in FIGS. 53 and 54, and as it has already been explained, the explanation will be omitted.

[0623] For example, the configuration of the preamble and control information symbols in frame structure A2201_1 in optical modulated signal A2003_1 in FIG. 55 is shown in FIG. 58, and the configuration of the preamble and control information symbols from "frame structure A2201_2 in optical modulated signal A2003_2" to "frame structure A2201_16 in optical modulated signal A2003_16" is shown in FIG. 62. Note that in FIG. 62, components that operate in the same way as in FIGS. 57 and 58 are assigned the same numbers, and a distinctive feature of FIG. 62 is that it does not include "symbol A2403 including information regarding the number of optical modulated signals being transmitted." In other words, transmitting device 100 transmits "symbol A2403 including information regarding the number of optical modulated signals being transmitted" only by optical modulated signal A2003_1.

[0624] At this time, in the receiving state of the receiving device 150 in Fig. 56, the receiving device 150 does not obtain "symbol A2403 including information about the number of optical modulated signals being transmitted," and therefore is unable to grasp the number of optical modulated signals transmitted by the transmitting device 100. In this case, the receiving device 150 determines that it is difficult to receive the data correctly, and stops signal processing of the receiving operation, thereby reducing unnecessary power consumption.

[0625] In the explanation of this example, it is explained that "the transmitting device 100 transmits 'symbol A2403 including information regarding the number of optically modulated signals being transmitted' using only optically modulated signal A2003_1," but this example is not limited thereto, and the same effect as described above can be obtained if "the transmitting device 100 transmits 'symbol A2403 including information regarding the number of optically modulated signals being transmitted' using some of the optically modulated signals A2003_1 to A2003_16."

[0626] As yet another example, "the transmitting device 100 may be configured to transmit a preamble and a control information symbol in some of the optically modulated signals A2003_1 to A2003_16."

[0627] As described above, when a transmitting device transmits multiple optically modulated signals, by transmitting the optically modulated signals as described in this embodiment, the receiving device can obtain the effect of obtaining high data reception quality or reducing power consumption.

[0628] In this embodiment, the number of optical modulated signals transmitted by the transmitting device has been described as 16, but this is not limited to this. For example, when the transmitting device has a configuration such as 100 in FIG. 53, the number of optical modulated signals to be transmitted may be changed depending on the transmission time. For example, 16 optical modulated signals may be transmitted in the first time period, 8 optical modulated signals may be transmitted in the second time period, and 1 optical modulated signal may be transmitted in the third time period. In this example, in the first time period, information "16" is transmitted in "symbol A2404 including information regarding the number of optical modulated signals being transmitted," information "8" is transmitted in "symbol A2404 including information regarding the number of optical modulated signals being transmitted," and information "1" is transmitted in "symbol A2404 including information regarding the number of optical modulated signals being transmitted" in the second time period.

[0629] Although the present embodiment has been described using the frame configuration of Figure 55 as an example, the frame configuration is not limited to this, and other symbols may be present in the frame. Also, the order in which the symbols are transmitted is not limited to the order in Figure 55.

[0630] Furthermore, although the configurations of the preamble and control information symbols have been described in Figures 57, 58, 61, and 62, similar operation may be possible even if some symbols are not present in each figure or different symbols are present in each figure. In other words, the configurations of the preamble and control information symbols are not limited to the configurations in Figures 57, 58, 61, and 62. Furthermore, the order in which the symbols constituting the preamble and control information symbols are transmitted is not limited to the examples in Figures 57, 58, 61, and 62.

[0631] (Embodiment 11) In this embodiment, a method for improving the reception quality of data at receiving apparatus 150 when, for example, the reception state of receiving apparatus 150 is as shown in FIG. 56 will be described.

[0632] As explained in the tenth embodiment, when receiving device 150 is in a state such as that shown in Fig. 56, it is difficult for receiving device 150 to correctly receive data. Also, the receiving state of receiving device 150 may become as shown in Fig. 63. In Fig. 63, parts that operate in the same way as in Fig. 56 are assigned the same numbers.

[0633] 63, the area illuminated by each light source in a light receiving unit such as an image sensor is small, which causes a problem of a decrease in the reception quality of data in the receiving device 150. Furthermore, when the line scan method or area-by-area line scan sampling is performed, the receiving device 150 may experience a significant decrease in the reception quality of data.

[0634] In this embodiment, an example of the configuration of a receiving device 150 that overcomes this problem will be described.

[0635] An example of the configuration of a transmitting device that transmits data is a transmitting device 100 shown in Fig. 53. Note that Fig. 53 has already been explained, so the explanation will be omitted.

[0636] FIG. 64 shows the configuration of a receiving device 150 that receives the optically modulated signal transmitted by the transmitting device 100 in FIG.

[0637] Furthermore, as an example of a configuration of a transmitting device that transmits data that is different from that of Fig. 53, there is a transmitting device 100 in Fig. 54. Note that Fig. 54 has already been explained, so its explanation will be omitted.

[0638] FIG. 65 shows the configuration of a receiving device 150 that receives the optically modulated signal transmitted by the transmitting device 100 in FIG.

[0639] The receiving device 150 in FIGS. 64 and 65 will be described below.

[0640] FIG. 64 shows an example of the configuration of a receiving device 150 that receives an optically modulated signal transmitted by the transmitting device 100 in FIG. 53, and components that operate in the same manner as in FIG. 53 are assigned the same numbers.

[0641] The lens (group) A3101 receives a lens control signal A3109 as input and controls the focal length, aperture, focus, and the like.

[0642] The image sensor (light receiving unit) A3103 receives the light A3102 that has passed through the lens, and outputs optical reception signals A2052_1 to A2502_M and an image signal A3104. The image signal A3104 may then be subjected to signal processing and displayed as an image on an internal display unit, or may be displayed as an image on an external display unit via an interface.

[0643] The data acquisition unit A2055 receives the received data A2054_1 to A2054_M as input, and outputs data A2056 and reception status information A3107.

[0644] The reception status information A3107 may be, for example, "information on the number of optically modulated signals being transmitted" obtained from "symbol A2403 including information on the number of optically modulated signals being transmitted" transmitted by the transmitting device 100 in embodiment 10, or "information on the optically modulated signal number" obtained from "symbol A2501 including information on the optically modulated signal number" transmitted by the transmitting device 100, or the reception status information A3107 may be reception status information generated from "information on the number of optically modulated signals being transmitted" or "information on the optically modulated signal number." Note that the present invention is not limited to this example.

[0645] The object recognition unit A3105 receives the image signal A3104, reception status information A3107, and instruction signal A3150 as inputs, and performs object recognition based on the instruction signal A3150. For example, if the instruction signal A3150 indicates that communication is to be performed, the object recognition unit A3105 begins recognizing the optical modulation signal. At this time, the object recognition unit A3105 receives the image signal A3104 and reception status information A3107 as inputs, and outputs an object recognition signal A3106. Specific operations will be described later.

[0646] The lens control unit A3108 receives the object recognition signal A3106 as input, recognizes the reception state, for example, as shown in Figures 56 and 63, and "determines whether to perform lens control, or if so, the focal length setting value, aperture setting value, and focus setting," and outputs a lens control signal A3109 corresponding to these controls. In Figure 64, the lens control unit A3108 receives the object recognition signal A3106 as input, but other input signals may also be present.

[0647] Figure 65 shows an example of the configuration of a receiving device 150 that receives an optically modulated signal transmitted by the transmitting device 100 in Figure 54, and components that operate in the same way as in Figures 53 and 54 are given the same numbers. Note that the operations of the lens(es) A3101, image sensor A3103, object recognition unit A3105, and lens control unit A3108 have already been explained, so explanations will be omitted here.

[0648] The error correction decoder A2155 receives the received data A2054_1 to A2054_M as input, and outputs data A2056 and reception status information A3107.

[0649] Next, a specific example of a method for controlling the lens (group) A3101 in FIGS. 64 and 65 will be described.

[0650] As explained in the tenth embodiment, for example, when the reception state of the receiving device 150 is as shown in Fig. 56, the light receiving unit does not receive the light emitted by some light sources, making it difficult for the receiving device 150 to receive data correctly. Also, as already explained, when the reception state of the receiving device 150 is as shown in Fig. 63, there is a problem in that the reception quality of the data of the receiving device 150 is poor.

[0651] On the other hand, when the receiving device 150 is in a receiving state such as that shown in FIGS. 59 and 60, the data reception quality is high.

[0652] From the above, data reception quality improves when receiving device 150 controls lens(es) A3101 so as to achieve the reception state shown in Figures 59 and 60. Receiving device 150 in Figures 64 and 65 is an example of a configuration that achieves this.

[0653] A specific example of control of the receiving device 150 in FIGS. 64 and 65 will be described.

[0654] Assume that the reception status of the receiving device 150 is, for example, as shown in Fig. 56. In this case, since the reception status information A3107 in Fig. 64 and Fig. 65 is information created based on "information related to the number of optically modulated signals being transmitted" and "information related to the numbers of optically modulated signals" as already explained, the object recognition unit A3105 in Fig. 64 and Fig. 65 recognizes that three optically modulated signals out of 16 optically modulated signals have been received.

[0655] Furthermore, the object recognition unit A3105 recognizes the "reception status of the optical modulation signals, for example, the position on the image sensor at which the three optical modulation signals are received" from the image signal A3104. In other words, the object recognition unit A3105 performs object recognition of the image shown in FIG. 56. The object recognition unit A3105 then recognizes the "reception status of the optical modulation signals" and "the fact that 16 optical modulation signals have not been received." Furthermore, in this example, the object recognition unit A3105 determines to perform lens control based on these recognition results, determines "a suitable focal length setting, a suitable aperture setting, and a suitable focus setting" to achieve suitable communication, and outputs an object recognition signal A3106 including this information. Note that the object recognition signal A3106 is sufficient as long as it includes at least the "suitable focal length setting," and does not necessarily include information on the suitable aperture setting and the suitable focus setting.

[0656] The lens control unit A3108 receives the object recognition signal A3106 as input and outputs a lens control signal A3109 for controlling the lens(es) A3101 based on information such as "a suitable focal length setting value, a suitable aperture setting value, and a suitable focus setting" contained in the object recognition signal A3106.

[0657] By performing such a series of operations, the receiving device 150 in Figures 64 and 65 will enter a receiving state such as that shown in Figures 59 and 60, thereby achieving the effect of obtaining high data reception quality.

[0658] In the above example, the case where the reception state of the receiving device 150 is controlled from Fig. 56 to "Fig. 59, Fig. 60" has been described as an example, but the present invention is not limited to this example, and the reception state of the receiving device 150 may be controlled from Fig. 63 to "Fig. 59, Fig. 60". However, the present invention is not limited to this example.

[0659] Next, examples of control of the receiving device 150 in FIGS. 66 and 67, which are different from those in FIGS. 64 and 65, will be described.

[0660] Figure 66 shows an example of the configuration of a receiving device 150 that receives an optically modulated signal transmitted by the transmitting device 100 of Figure 53, and parts that operate in the same way as in Figure 64 are given the same numbers, and explanations of parts that have already been explained will be omitted.

[0661] The receiving device 150 in FIG. 66 differs from the receiving device 150 in FIG. 64 in that a signal processing unit A3302 is present after the image sensor A3103.

[0662] The signal processing unit A3302 is assumed to have at least a zoom (image enlargement (reduction)) processing function.

[0663] Therefore, the signal processing unit A3302 receives as input the image signal A3301, the zoom signal A3300, the object recognition signal A3106, and the instruction signal A3150, and when the instruction signal A3150 indicates "shooting mode (taking a photo)", the signal processing unit A3302 performs zoom signal processing on the image signal A3301 based on the zoom (image enlargement (reduction)) information of the zoom signal A3300, and outputs the processed image signal A3104.

[0664] When the instruction signal A3150 indicates "communication mode (performing communication)," the signal processing unit A3302 performs signal processing for zooming on the image signal A3301 based on information such as "a suitable focal length setting value, a suitable aperture setting value, and a suitable focus setting" contained in the object recognition signal A3106, and outputs the processed image signal A3104 and the processed optical reception signals 2052_1 to A2052_M. This improves the reception state as described above, thereby achieving the effect of improving the data reception quality.

[0665] The method for improving the reception state in the lens control unit A3108 has already been explained, so the explanation will be omitted.

[0666] By doing so, the receiving device 150 can improve the reception state and thereby improve the data reception quality. In Fig. 66, if the lens(es) A3101 does not have a focal length changing function, the focal length will not be changed to improve reception.

[0667] Figure 67 shows an example of the configuration of a receiving device 150 that receives an optically modulated signal transmitted by the transmitting device 100 in Figure 54, and parts that operate in the same way as in Figure 65 are given the same numbers, and explanations of parts that have already been explained will be omitted.

[0668] The receiving device 150 in FIG. 67 differs from the receiving device 150 in FIG. 65 in that, similarly to FIG. 66, a signal processing unit A3302 is present after the image sensor A3103.

[0669] The details of the operation of the signal processing unit A3302 have already been explained, so the explanation will be omitted. As already explained, the reception state improves, and therefore the effect of improving the reception quality of data can be obtained.

[0670] The method for improving the reception state in the lens control unit A3108 has already been explained, so the explanation will be omitted.

[0671] By doing so, the receiving device 150 can improve the reception state and thereby improve the data reception quality. In Fig. 67, if the lens(es) A3101 does not have a focal length changing function, the focal length will not be changed to improve reception.

[0672] In the receiving device 150 of Figures 64, 65, 66, and 67, it is assumed that the lens(es) A3101 can be set to multiple values ​​as the focal length. For example, it is possible to set the focal length to between 12 mm and 35 mm, or to set the focal length to 12 mm and 25 mm. The following explanation will be based on this example.

[0673] As a first example, consider the case where multiple discrete values ​​are supported as focal lengths.

[0674] When the receiving device 150 in Figures 64, 65, 66, and 67 is set to "communication mode" by instruction signal A3150, it will start communication. At this time, it is recommended to set the focal length of lens(es) A3101 to, for example, 12 mm, which is the widest angle. This is because, when set to the widest angle, it is highly likely that a reception state in which it is difficult to receive some optical modulations, as shown in Figure 56, can be avoided. This has the effect of improving the data reception quality. However, to further improve the data reception quality, the focal length, etc. may be controlled to a suitable value.

[0675] In this example, focal lengths of 12 mm and 25 mm are supported, but even if two or more focal lengths are supported, setting the focal length to, for example, the widest angle at the start of communication can be an effective method for improving data reception quality.

[0676] As a second example, consider the case where the focal length can be set continuously (or finely).

[0677] When the receiving device 150 in FIGS. 64, 65, 66, and 67 is set to "communication mode" by the instruction signal A3150, it starts communication. At this time, it is recommended to set the focal length of the lens(es) A3101 to, for example, 12 mm, which is the widest angle. This is because, when set to the widest angle, it is highly likely that a reception state in which it is difficult to receive some optical modulations, as shown in FIG. 56, can be avoided. This has the effect of improving data reception quality. However, in this example, the focal length can be set more precisely, so it is highly likely that the same effect can be achieved even if it is set to, for example, 14 mm. However, to further improve data reception quality, the focal length, etc., may be controlled to a suitable value.

[0678] Consider a case where the signal processing unit A3302 has a zoom (enlargement (reduction) of an image) processing function in the receiving device 150 of Figures 66 and 67. In this case, the following description will be given taking as an example a case where image enlargement by 1x (no enlargement), image enlargement by 2x, and image enlargement by 4x.

[0679] When the receiving device 150 in FIGS. 66 and 67 is set to "communication mode" by the instruction signal A3150, it will start communication. At this time, it is recommended that the zoom (image enlargement (reduction)) of the signal processing unit A3302 be set to "1x image enlargement (no enlargement)," which is the widest angle. This is because, when set to the widest angle, it is highly likely that a reception state in which it is difficult to receive some optical modulations, as shown in FIG. 56, can be avoided. This has the effect of improving the data reception quality. However, to further improve the data reception quality, the zoom value may be controlled to a suitable value.

[0680] (Supplementary Note 1) Naturally, the embodiments and other contents described in this specification may be combined and implemented.

[0681] Furthermore, each embodiment is merely an example, and even if a "modulation method, error correction coding method (error correction code to be used, code length, coding rate, etc.), control information, etc." is exemplified, it is possible to implement the same configuration even if a different "modulation method, error correction coding method (error correction code to be used, code length, coding rate, etc.), control information, etc." is applied.

[0682] Regarding the modulation method, even if a modulation method other than the modulation methods described in this specification is used, it is possible to implement the embodiments and other contents described in this specification. For example, APSK (Amplitude Phase Shift Keying) (e.g., 16APSK, 64APSK, 128APSK, 256APSK, 1024APSK, 4096APSK, etc.), PAM (Pulse Amplitude Modulation) (e.g., 4PAM, 8PAM, 16PAM, 64PAM, 128PAM, 256PAM, 1024PAM, 4096PAM, etc.), PSK (Phase Shift Keying) (e.g., BPSK, QPSK, 8PSK, 16PSK, 64PSK, 128PSK, 256PSK, 1024PSK, 4096PSK, etc.), QAM (Quadrature Amplitude Modulation) (e.g., 4QAM, 8QAM, 16QAM, 64QAM, 128QAM, Modulation schemes such as 256QAM, 1024QAM, and 4096QAM may also be applied, and uniform or non-uniform mapping may be used for each modulation scheme. Furthermore, the method of arranging 2, 4, 8, 16, 64, 128, 256, 1024, etc. signal points on the IQ plane (modulation schemes having 2, 4, 8, 16, 64, 128, 256, 1024, etc. signal points) is not limited to the signal point arrangement method of the modulation scheme shown in this specification.

[0683] The wireless device described in this specification may be, for example, communication and broadcasting equipment such as a broadcast station, base station, access point, terminal, mobile phone, etc., or communication equipment such as a television, radio, terminal, personal computer, mobile phone, access point, base station, etc. The wireless device described in this specification may also be a device having a communication function, and may be configured to be connectable via some kind of interface to a device for executing an application, such as a television, radio, personal computer, or mobile phone.

[0684] In addition, the receiving unit described in this specification may be equipped in, for example, communication and broadcasting equipment such as broadcasting stations, base stations, access points, terminals, and mobile phones, as well as communication equipment such as televisions, radios, terminals, personal computers, mobile phones, access points, and base stations.

[0685] In radio communication using radio waves in this embodiment, symbols other than data symbols, such as pilot symbols (preambles, unique words, postambles, reference symbols, etc.), control information symbols, etc. may be arranged in any manner in a frame. Here, they are called pilot symbols and control information symbols, but any naming method may be used, and the role of each symbol is important.

[0686] The pilot symbol may be, for example, a known symbol modulated by PSK modulation in the transmitter / receiver (or the receiver may be able to know the symbol transmitted by the transmitter by synchronizing with the symbol), and the receiver uses this symbol to perform frequency synchronization, time synchronization, channel estimation (for each modulated signal) (CSI (Channel State Information) estimation), signal detection, etc.

[0687] In addition, control information symbols are used to transmit information that needs to be transmitted to the other party in order to realize communication other than data (such as applications) (for example, the modulation method, error correction coding method, coding rate of the error correction coding method used in the communication, setting information in the upper layer, etc.).

[0688] (Supplementary Note 2) The video coding method described in each of the above embodiments may be a method conforming to specifications defined under names such as MPEG (Moving Picture Experts Group) 2, H.264 / AVC (Advanced Video Coding), H.265 / HEVC (High-Efficiency Video Coding), VC-1, VP8, VP9, ​​etc. However, the video coding method described in each of the above embodiments may be a video coding method different from the methods listed above.

[0689] The present disclosure is not limited to the embodiments and can be implemented with various modifications. For example, although the embodiments describe the case where the communication method is performed as a communication device, the present disclosure is not limited to this and can be realized by software, hardware, or software linked to hardware.

[0690] For example, a program for executing the communication method, transmission method, or reception method may be stored in advance in a ROM (Read Only Memory), and the program may be run by a CPU (Central Processor Unit).

[0691] In addition, a program for executing the above-mentioned communication method, transmission method, or reception method may be stored in a computer-readable storage medium, and the program stored in the storage medium may be recorded in the computer's RAM (Random Access Memory), causing the computer to operate in accordance with the program.

[0692] Each functional block used in the description of each of the above embodiments may be partially or entirely realized as an LSI (Large Scale Integration) integrated circuit, and each process described in each of the above embodiments may be partially or entirely controlled by a single LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of a single chip that includes some or all of the functional blocks. The LSI may have data input and output. Depending on the level of integration, an LSI may also be referred to as an IC (Integrated Circuit), a system LSI, a super LSI, or an ultra LSI. The integration method is not limited to LSIs; it may also be realized using dedicated circuits, general-purpose processors, or dedicated processors. Furthermore, a field programmable gate array (FPGA), which can be programmed after LSI fabrication, or a reconfigurable processor, which allows the connections and settings of circuit cells within an LSI to be reconfigured, may also be used. The present disclosure may be realized as digital or analog processing. Furthermore, if an integrated circuit technology that replaces LSIs emerges due to advances in semiconductor technology or other derivative technologies, that technology may naturally be used to integrate functional blocks. The application of biotechnology is one possibility.

[0693] (Supplementary Note 3) At least one of the FPGA (Field Programmable Gate Array) and the CPU (Central Processing Unit) may be configured to download all or part of the software required to implement the communication method, transmission method, or reception method described in this disclosure via wireless or wired communication. Furthermore, all or part of the software for updates may be downloaded via wireless or wired communication. The downloaded software may then be stored in a storage unit, and at least one of the FPGA and the CPU may be operated based on the stored software to perform the digital signal processing described in this disclosure.

[0694] In this case, the device having at least one of an FPGA and a CPU may be connected to a communication modem wirelessly or via a wired connection, and the communication method, transmission method, or reception method described in this disclosure may be realized by this device and the communication modem.

[0695] For example, a communication device (transmitting device or receiving device) such as a base station, AP, or terminal described in this specification may include at least one of an FPGA and a CPU, and the communication device may include an interface for externally obtaining software for operating at least one of the FPGA and the CPU. Furthermore, the communication device may include a storage unit for storing the software obtained from the outside, and may operate the FPGA and CPU based on the stored software to realize the signal processing described in the present disclosure.

[0696] A first "car or vehicle" may be equipped with a transmitting device as described herein, and a second "car or vehicle" may be equipped with a receiving device as described herein, and data may be transmitted and received.

[0697] The "transmitting device or part of the functionality of the transmitting device" described in this specification may be connected to a first "car or vehicle" via an interface, and the "receiving device or part of the receiving device" described in this specification may be connected to a second "car or vehicle" via an interface, and data transmission by transmission and reception may be performed.

[0698] Furthermore, the first "car or vehicle" may be equipped with the transmitting device described in this specification, and data may be transmitted and received between this transmitting device and the receiving device described in this specification.

[0699] A second "car or vehicle" may be equipped with a receiving device as described herein, and data may be transmitted and received between this receiving device and a transmitting device as described herein.

[0700] Furthermore, the "transmitting device or part of the functionality of the transmitting device" described in this specification may be connected to a first "car or vehicle" via an interface, and data may be transmitted and received between this series of transmitting devices and the receiving device described in this specification.

[0701] The "receiving device or part of the receiving device" described in this specification may be connected to a second "car or vehicle" via an interface, and data may be transmitted and received between the transmitting device described in this specification and this set of receiving devices.

[0702] If a "car or vehicle" is equipped with a transmitting device or part of a transmitting device described in this specification, or if a "car or vehicle" is connected via an interface to a "transmitting device described in this specification" or "part of the functionality of a transmitting device described in this specification," the light source equipped in the "car or vehicle" may be used as the light source equipped in the transmitting device described in this specification.

[0703] For example, as shown in FIG. 68, a car B100 is provided with light sources B101_1, B101_2, B101_3, and B101_4, and one or more of these light sources may be used as light sources for transmitting optically modulated signals by the transmitting device described in this specification.

[0704] Furthermore, the transmitting device or a device connected to the transmitting device may have a function for selecting "which light source to use as a light source for transmitting an optically modulated signal by the transmitting device described in this specification" from among the multiple light sources mounted on the car B100. Furthermore, the brightness, irradiation angle, and position of the light source may be set together.

[0705] If "a car or vehicle is equipped with a receiving device or part of a receiving device described in this specification," or "a car or vehicle is connected to a receiving device described in this specification or part of the functions of a receiving device described in this specification via an interface," the light receiving unit (e.g., an image sensor, photodiode, etc.) equipped in the car or vehicle may be used as the light receiving unit equipped in the receiving device described in this specification.

[0706] For example, as shown in FIG. 69, a vehicle B100 has light receiving units B201_1, B201_2, B201_3, B201_4, B201_5, and B201_6, and one or more of these light receiving units may be used as light receiving units for the receiving device described in this specification to receive optically modulated signals.

[0707] Furthermore, the receiving device or a device connected to the receiving device may have a function for selecting "which light receiving unit is to be used as the light receiving unit for the receiving device described in this specification to receive the optically modulated signal" from among the multiple light receiving units mounted on the car B100. Furthermore, the angle and position of the light receiving unit may be set accordingly.

[0708] Furthermore, the fact that the receiving device described in this specification is able to receive data may be displayed on the front panel of a car or in the cockpit of a vehicle.Also, the fact that the receiving device described in this specification is able to receive data may be notified to the user by vibrating the steering wheel of a car or a vibrator provided on the steering wheel.

[0709] (Supplementary Note 4) In this specification, a server may provide an application for processing related to the receiving device, and a terminal may realize the functions of the receiving device described in this specification by installing this application. Note that the application may be provided to the terminal by connecting a communication device equipped with the transmitting device described in this specification to the server via a network, or the application may be provided to the terminal by connecting another communication device having a transmitting function to the server via a network.

[0710] Similarly, in this specification, a server may provide an application relating to processing related to the transmitting device, and a communication device may install the application to realize the functions of the transmitting device described in this specification. Note that a method is also conceivable in which the application is provided to another communication device by connecting the communication device to the server via a network.

[0711] In addition, the server may provide software relating to the light source provided in the transmitting device and the light receiving unit provided in the receiving device, and by obtaining this software, the light source provided in the transmitting device may be capable of transmitting optically modulated signals, and the light receiving unit provided in the receiving device may be capable of receiving optically modulated signals.

[0712] Furthermore, the transmitting device in this specification may have the functionality of a server, and the application that the transmitting device has may be provided to the communication device using some communication means, and the communication device may be able to realize the receiving device in this specification by using the application obtained by downloading it.

[0713] In this specification, the terms "illumination unit" and "light source" are used, but the light may be emitted by a display or projector that displays images, videos, advertisements, etc., and the light may contain an optical modulation signal. In other words, the "illumination unit" and "light source" may have a function other than emitting light. Furthermore, the "illumination unit" and "light source" may be composed of multiple "lights" and "light sources."

[0714] Furthermore, the transmission method used by the communication device that generates the optical modulated signal and emits light may be a method other than the transmission methods described in this specification, and the optical modulated signal may contain information other than that described in this specification.

[0715] Furthermore, the illumination / light source itself, such as an LED, may have the function of the transmitting device described in this specification.

[0716] Furthermore, although the examples described in this specification are given using the case where the transmitting device and receiving device are installed in a vehicle, this is not limited to this, and the transmitting device and receiving device may be installed in other things, or even if the transmitting device and receiving device exist alone, the operations described in this specification can be performed and similar effects can be obtained.

[0717] (Supplementary Note 5) The communication device and the receiving device in the present disclosure may be any of the first to eleventh embodiments.

[0718] That is, a first communication device according to one aspect of the present disclosure includes a light receiving unit that receives a first optical signal that transmits first identifier information indicating an identifier of a first communication device and a second optical signal that transmits second identifier information indicating an identifier of a second communication device to generate a received signal, a demodulation unit that demodulates the received signal to obtain the first identifier information and the second identifier information, a camera that photographs an area including the first optical signal and the second optical signal and obtains video or still image data, a control unit that selects either the first identifier information or the second identifier information based on the video or still image data, and a communication unit that communicates with a communication device corresponding to the selected identifier information.

[0719] A second communication device according to one embodiment of the present disclosure includes a light receiving unit that captures an image of a predetermined area and acquires a received signal for demodulating an optical signal irradiated onto the predetermined area, and video or still image data for use in image processing, a demodulation unit that demodulates the image data and acquires multiple pieces of identifier information indicating the identifiers of other corresponding communication devices, a control unit that selects one piece of identifier information from the multiple pieces of identifier information based on the video or still image data, and a communication unit that performs wireless communication with other communication devices corresponding to the selected identifier information.

[0720] A first receiving device according to one aspect of the present disclosure includes a first light receiving unit that receives a first optical signal that transmits first identifier information indicating an identifier of a first communication device and a second optical signal that transmits second identifier information indicating an identifier of a second communication device to generate an optical receiving signal, a demodulation unit that demodulates the optical receiving signal to obtain the first identifier information and the second identifier information, a second light receiving unit that obtains video or still image data of an area including the first optical signal and the second optical signal, and a control unit that selects either the first identifier information or the second identifier information based on the video data or still image data.

[0721] A second receiving device according to one aspect of the present disclosure includes a receiving unit that receives a first optical signal transmitting first identifier information indicating an identifier of a first communication device and a second optical signal transmitting second identifier information indicating an identifier of a second communication device to generate a received signal, a demodulation unit that demodulates the received signal to obtain the first identifier information and the second identifier information, a camera that photographs an area including the first optical signal and the second optical signal to obtain video data or still image data, and an analysis unit that analyzes the video data or still image data to generate relative position information indicating the positional relationship between a first transmitter that transmitted the first optical signal and a second transmitter that transmitted the second optical signal.

[0722] A third receiving device according to one aspect of the present disclosure includes a light receiving unit that receives a first optical signal transmitting first identifier information indicating an identifier of a first communication device and a second optical signal transmitting second identifier information indicating an identifier of a second communication device using an image sensor and generates a received signal, a demodulation unit that demodulates the received signal to obtain the first identifier information and the second identifier information, and an analysis unit that generates first location information indicating the location of a first transmitter that transmitted the first optical signal and second location information indicating the location of a second transmitter that transmitted the second optical signal.

[0723] A fourth receiving device according to one aspect of the present disclosure includes a light receiving unit that photographs a predetermined area and acquires a received signal for demodulating an optical signal irradiated onto the predetermined area, and video or still image data for use in image processing, a demodulation unit that demodulates the received signal to generate demodulated data, and an analysis unit that analyzes the video or still image data to generate attribute information indicating the attributes of a transmitter that transmitted an optical signal corresponding to the demodulated data.

[0724] The receiving device according to the present disclosure may be any of the eighth to eleventh embodiments.

[0725] That is, a receiving device according to one aspect of the present disclosure includes an image sensor that captures an image by photographing, and a receiving unit that receives, in parallel, N different optical signals transmitted from a plurality of light sources by sampling a plurality of pixels included in each of N (N is an integer equal to or greater than 2) regions included in an imaging surface of the image sensor. For example, as shown in Fig. 42, the receiving device performs line scan sampling for each of regions A, B, C, and D, thereby receiving, in parallel, different optical signals from the light sources corresponding to the respective regions.

[0726] This allows the receiving device to safely obtain information such as the SSID by receiving the optical signal. In addition, since different optical signals transmitted from multiple light sources are received in parallel, the data transmission speed can be improved.

[0727] The receiving device may further include at least one lens and a lens control unit that controls the at least one lens, and the lens control unit may control the at least one lens so that light from each of the plurality of light sources is projected onto the image sensor via the at least one lens. For example, the lens control unit may control the focal length of the at least one lens. Specifically, the at least one lens may be, for example, lens(es) A3101 shown in FIGS. 64 to 67, and the lens control unit may be, for example, lens control unit A3108 shown in FIGS. 64 to 67. Control of the focal length by the lens control unit changes the reception state shown in FIGS. 56 and 63, for example, to the reception state shown in FIGS. 59 and 60, for example. Note that not only the focal length but also the aperture and focus may be controlled.

[0728] This provides the advantage of being able to obtain high data reception quality.

[0729] Furthermore, the optical signals transmitted from each of the plurality of light sources may include signal number information regarding the number of optical signals transmitted from the plurality of light sources, and the receiving device may further include a recognition unit that recognizes a reception state of the N optical signals, the recognition unit recognizing the reception state based on N, which is the number of optical signals received by the receiving unit, and the signal number information included in the optical signals received by the receiving unit, and the lens control unit may control the focal length of the at least one lens based on the reception state recognized by the recognition unit. For example, the recognition unit may determine whether the reception state is a state in which all optical signals transmitted from the plurality of light sources are received by the receiving unit, based on N, which is the number of optical signals received by the receiving unit, and the number of optical signals indicated by the signal number information, and the lens control unit may control the at least one lens to shorten the focal length of the at least one lens when the recognition unit determines that not all the optical signals are received by the receiving unit. Specifically, the signal number information is information included in the "symbol A2403 including information on the number of optical modulation signals being transmitted" shown in Fig. 57 and Fig. 58. Also, the recognition unit is the object recognition unit A3105 shown in Fig. 64 to Fig. 67.

[0730] This allows a determination to be made as to whether all optical signals transmitted from multiple light sources have been received based on the number of received optical signals (N) and the number of optical signals indicated by the signal count information. If all optical signals have not been received, the focal length of at least one lens is shortened. As a result, the angle of view is widened, allowing all light from multiple light sources to be projected onto the image sensor, allowing all optical signals to be received. This allows for high data reception quality. [Industrial Applicability]

[0731] One aspect of the present disclosure is useful in optical communication systems. [Explanation of symbols]

[0732] 100,400,1000,14...

Claims

1. one or more image sensors for acquiring image data and optical signals; a processor; The processor: detecting an object having a light source that transmitted the optical signal by performing image processing on the image data; demodulating the optical signal to obtain demodulated data; storing the demodulated data in a memory in association with the detected object; Receiving device.

2. the demodulated data includes connection information for connecting to the object via wireless communication.

2. The receiving device according to claim 1.

3. A receiving method performed by a receiving device comprising one or more image sensors, comprising: acquiring image data and optical signals by the one or more image sensors; detecting an object having a light source that transmitted the optical signal by performing image processing on the image data; demodulating the optical signal to obtain demodulated data; storing the demodulated data in a memory in association with the detected object; Receiving method.

4. the demodulated data includes connection information for connecting to the object via wireless communication. The receiving method according to claim 3.

Images