Receiving apparatus and receiving method

Abstract

To provide a receiving device that can safely obtain information. [Solution] The receiving device A2000 has one or more image sensors A8001-1 that acquire image data and received signals, and a processor A10001. The processor A10001 detects objects by performing image processing on the image data, acquires demodulated data by demodulating the received signals, and stores the demodulated data in memory A10002 in association with the detected objects.

Description

Technical Field

[0001] The present disclosure relates to a receiving apparatus and a receiving method.

Background Art

[0002] For purposes such as using services based on the position of a terminal, there is a method of using GPS (Global Positioning System) as a method of acquiring information such as the position of the terminal itself. In the method using GPS, the terminal receives a modulated signal transmitted from a satellite and estimates its own location by performing positioning calculations. However, when it is difficult for the terminal to receive the radio waves transmitted by the satellite (for example, indoors), it becomes difficult for the terminal to estimate its own location.

[0003] As a method for the terminal to estimate its own location in such a case, for example, as disclosed in Non-Patent Document 1, there is a method of estimating 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 Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, for example, when a terminal does not hold information such as the SSID (service set identifier) of an access point to be accessed, it is not easy for the terminal to appropriately determine which access point to connect to among a plurality of surrounding access points. For this reason, for example, when a terminal connects to an access point to obtain information such as its own location, there is a possibility of connecting to an access point with an insecure SSID, posing threats such as information leakage.

[0006] One aspect of the present disclosure promotes providing a receiving device or the like that can safely obtain information used to identify an access point to which a terminal should connect.

Means for Solving the Problems

[0007] A receiving device according to one aspect of the present disclosure includes one or more image sensors that acquire image data and a received signal, and a processor. The processor detects an object by performing image processing on the image data, acquires demodulated data by demodulating the received signal, and stores the demodulated data in a memory in association with the detected object.

[0008] A receiving method according to one aspect of the present disclosure is a receiving method performed by a receiving device including one or more image sensors, the method including: acquiring an image and a reception signal by the one or more image sensors; detecting an object by performing image processing on the image data; acquiring demodulated data by demodulating the reception signal; and storing the demodulated data in a memory in association with the detected object.

[0009] These general or specific aspects may be implemented in a system, method, integrated circuit, computer program, or recording medium, or may be implemented in any combination of a system, device, method, integrated circuit, computer program, and recording medium.

Advantages of the Invention

[0010] According to one aspect of the present disclosure, a terminal can obtain information securely.

[0011] Further advantages and effects in one aspect of the present disclosure will be clarified from the specification and drawings. Such advantages and / or effects are provided by some embodiments and the features described in the specification and drawings, respectively, but not necessarily all are provided to obtain one or more of the same features.

Brief Description of the Drawings

[0012]

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Mode for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0014] [Example of First Visible Light Communication Modulation and Demodulation Method] In the present embodiment, an optical communication method for transmitting and receiving a modulation signal as an optical signal is used.

[0015] 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.

[0016] [Line Scan Sampling] Smartphones or digital cameras are equipped with image sensors such as CMOS (Complementary Metal Oxide Semiconductor) sensors. The image captured by the CMOS sensor does not exactly show the scenery at the exact same time for the whole image. For example, as shown in Non-Patent Documents 2 and 3, by the rolling shutter method that performs a shutter operation for each row, the amount of light received by the sensor is read for each line. Therefore, in consideration of the time required for reading, the start and end of light reception are controlled with a time difference for each line. That is, the image captured by the CMOS sensor is in a form where a large number of lines with a slight time lag are overlapped during the exposure period.

[0017] In the first example of the visible light communication method, based on a method that focuses on the properties of this CMOS sensor, high-speed reception of visible light signals is achieved. That is, in the first example of the visible light communication method, by utilizing the fact that the exposure time varies slightly for each line, as shown in FIG. 1, from a single image (the captured image of the image sensor), the luminance and color of the light source at multiple time points can be measured for each line, and a signal modulated at a speed higher than the frame rate can be captured.

[0018] Hereinafter, this sampling method is referred to as "line scan sampling", and a column of pixels exposed at the same timing is referred to as an "exposure line".

[0019] Note that "line scan sampling" can be realized by the rolling shutter method using a CMOS sensor. However, even if the rolling shutter method is realized by a sensor other than a CMOS sensor, for example, a CCD (Charge-Coupled Device) sensor, an organic (CMOS) sensor exemplified by Non-Patent Document 4, etc., "line scan sampling" can be similarly implemented.

[0020] However, in the imaging settings during imaging in the camera function (video or still image shooting function), even if a light source that blinks at high speed is photographed, the blinking does not appear as a stripe pattern along the exposure line. This is because in this setting, the exposure time is sufficiently longer than the blinking period of the light source. Therefore, as shown in FIG. 2, the change in luminance due to the blinking (emission pattern) of the light source is averaged, the change in pixel values between exposure lines becomes small, and an almost uniform image is obtained.

[0021] In contrast, as shown in FIG. 3, by setting the exposure time to about the blinking period of the light source, the blinking state (emission pattern) of the light source can be observed as a change in the luminance of the exposure line. In FIG. 3, the length of the exposure period is set to be slightly longer than the length of the minimum period during which the same emission state continues, and the difference in the start time of the exposure period between adjacent exposure lines is set to be shorter than the length of the minimum period during which the same emission 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 to be shorter than the length of the minimum period during which the same emission state continues, or may be set to about twice the length of the minimum period during which the same emission state continues. Also, as an optical communication method, not only a method in which an optical signal is represented by a combination of rectangular waves as shown in FIG. 4A, but also a method in which the optical signal changes continuously may be used. In any case, for the receiving device of the optical communication method, the difference in the start time or end time of the exposure period between temporally adjacent exposure lines is set to be the same as or less than the sampling interval corresponding to the sampling rate required to receive and demodulate the optical signal with respect to the sampling rate. Also, the receiving device of the optical communication method sets the length of the exposure period to be the same as or less than the sampling interval. However, the receiving device of the optical communication method may set the length of the exposure period to be 1.5 times or less of the sampling interval, or 2 times or less of the sampling interval.

[0022] For example, the exposure line is designed to be parallel to the long side direction of the image sensor. In this case, as an example, when the frame rate is 30 fps (frames per second), at a resolution of 1920×1080, more than 32,400 samples per second can be obtained, and at a resolution of 3840×2160, more than 64,800 samples per second can be obtained.

[0023] <Application Example of Line Scan Sampling> In the above description, line scan sampling for reading a signal indicating the amount of light received for each line has been described. However, the sampling method of the optical signal using an image sensor such as a CMOS is not limited to this. As the sampling method used for receiving the optical signal, various methods capable of acquiring a signal sampled at a sampling rate higher than the frame rate used for shooting a normal video are applicable. For example, by the global shutter method in which each pixel has a shutter function shown in Non-Patent Document 2 and Non-Patent Document 3, a method of controlling the exposure period for each pixel and reading out the signal, or a method of controlling the exposure period in units of a group of a plurality of pixels arranged in a shape other than a line shape and reading out the signal may be used. Further, a method in which signals are read out a plurality of times from the same pixel within a period corresponding to one frame at the frame rate used for shooting a normal video may be used.

[0024] <Sampling by frame> Furthermore, it is possible to sample the optical signal even in a method in which the frame rate is increased by the frame rate method in which each pixel has a shutter function shown in Non-Patent Document 2 and Non-Patent Document 3.

[0025] The embodiments described below can be realized by any of the methods of, for example, "line scan sampling", "application examples of line scan sampling", and "sampling by frame" which have already been described.

[0026] <Light source and modulation method> In visible light communication, for example, an LED (Light Emitting Diode) can be used as a transmitter. LEDs are becoming popular as backlight light sources for lighting or displays and can be blinked at high speed.

[0027] However, the light source used as a transmitter for visible light communication cannot be freely blinked for visible light communication. If the change in brightness due to visible light communication can be recognized by humans, it will impair the original function of the light source such as lighting. Therefore, it is required that the transmission signal does not cause a flicker sensation to human eyes and illuminates with a desired brightness.

[0028] As a modulation method to meet this requirement, for example, there is a modulation method called 4PPM (4-Pulse Position Modulation). As shown in Fig. 4A, 4PPM is a method of expressing 2 bits by four combinations of light and dark of the light source. Also, as shown in Fig. 4A, since three out of four times are in the bright state and one time is in the dark state in 4PPM, regardless of the content of the signal, the average brightness (average luminance) is 3 / 4 = 75%.

[0029] For comparison, as a similar method, there is the Manchester coding method shown in Fig. 4B. The Manchester coding method is a method of expressing 1 bit in two states, and the modulation efficiency is the same 50% as that of 4PPM. However, since one out of two times is in the bright state and one time is in the dark state, the average luminance is 1 / 2 = 50%. That is, it can be said that 4PPM is more suitable than the Manchester coding method as a modulation method for visible light communication. However, since the communication performance does not deteriorate even when the change in brightness due to visible light communication is recognized by humans, there is no problem in using a method that causes a change in brightness recognized by humans depending on the application. Therefore, the transmitter (light source) may generate a modulation signal using a modulation method such as ASK (Amplitude Shift Keying) method, PSK (Phase Shift Keying) method, PAM (Pulse Amplitude Modulation), etc., and turn on and irradiate the light source.

[0030] <Overall configuration example of communication system> As shown in Fig. 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 (detects) the optical signal. For example, there are two types of transmitters: a variable optical transmitter that changes the transmission content according to the video or content to be displayed, and a fixed optical transmitter that continuously transmits a fixed transmission content. However, even with a configuration in which either a variable optical transmitter or a fixed optical transmitter exists, an optical communication system can be configured.

[0031] The receiver can receive the optical signal from the transmitter and, for example, acquire the related information associated with the optical signal and provide it to the user.

[0032] As described above, the outline of the visible light communication method has been explained. However, 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 perform data transmission using a plurality of light sources. Also, the light receiving unit of the receiving device may be a communication method that uses a device capable of converting an optical signal into an electrical signal, such as a photodiode, instead of an image sensor such as a CMOS. In this case, since it is not necessary to perform sampling using the line scan sampling described above, even a method that requires sampling of 32,400 or more per second can be applied. Also, depending on the application, for example, a communication method using radio waves of frequencies other than visible light, such as infrared rays and ultraviolet rays, may be used.

[0033] (Embodiment 1) Fig. 6 shows an example of the configuration of the device 100 and the terminal 150 in this embodiment.

[0034] [Configuration of Device 100] The device 100 (corresponding to the transmitter of visible light communication) includes a visible light source such as an LED (Light Emitting Diode), illumination, or light (collectively also referred to as a light source). Hereinafter, the device 100 may also be referred to as the "first device".

[0035] In the first device 100 of FIG. 6, the transmission unit 102 takes, for example, information regarding a location or position 101 as an input. Also, the transmission unit 102 may take information regarding time 105 as an input. Further, the transmission unit 102 may take both the information regarding a location or position 101 and the information regarding time 105 as inputs.

[0036] The transmission unit 102 takes the information regarding a location or position 101 and / or the information regarding time 105 as inputs, generates a (light) modulation signal 103 based on these input signals, and outputs the modulation signal 103. Then, the modulation signal 103 is transmitted, for example, from a light source 104.

[0037] Here, an example of the information regarding a location or position 101 will be described.

[0038] <Example 1> The information regarding a location or position 101 may be information on the latitude and / or longitude of a location / position. For example, information such as "45 degrees north latitude, 135 degrees east longitude" may be used as the information regarding a location or position 101.

[0039] <Example 2> The information regarding a location or position 101 may be address information. For example, information such as "1-1-1, ○○-cho, Chiyoda-ku, Tokyo" may be used as the information regarding a location or position 101.

[0040] <Example 3> The information regarding a location or position 101 may be information on a building, facility, etc. For example, information such as "Tokyo Tower" may be used as the information regarding a location or position 101.

[0041] <Example 4> The information regarding a location or position 101 may be information on the specific location / position of something installed in a building, facility, etc.

[0042] For example, assume that there is a space in a parking lot where five cars can be parked. At this time, 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, the information "A-3" may be used as the information related to the location or the information 101 related to the position.

[0043] Note that such an example is not limited to the case of a parking lot. For example, information related to "areas, seats, stores, facilities, etc." in concert facilities, stadiums for baseball, soccer, tennis, etc., airplanes, airport lounges, railways, stations, etc. may also be used as the information related to the location or the information 101 related to the position.

[0044] The examples of the information 101 related to the location or the position have been described above. Note that the method of configuring the information 101 related to the location or the position is not limited to the above examples.

[0045] [Configuration of Terminal 150] The terminal 150 (corresponding to the receiver of visible light communication) in FIG. 6 receives the modulated signal 103 transmitted from the first device 100.

[0046] The light receiving unit (receiver) 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 the light including the modulated signal transmitted from the first device 100 and outputs a received signal 152.

[0047] Note that the received signal 152 output from the light receiving unit 151 may be a signal including image and video information acquired by an image sensor, or may be an output signal of an element that performs other opto-electrical conversion (converts light into an electrical signal). In the following description, when it is described that the receiving device receives the modulation signal without particularly describing the processing performed by the light receiving unit 151, it means that the receiving device performs opto-electrical conversion (converts light into an electrical signal) from the light including the modulation signal in the light receiving unit 151 to obtain the "modulation signal for transmitting information" or the "image / video signal" and the "modulation signal for transmitting information". However, the method described above is an example of the method for the receiving device to receive the modulation signal, and the method for receiving the modulation signal is not limited to these.

[0048] Then, the receiving unit 153 takes the received signal 152 as an input, performs processing such as demodulation and error correction decoding on the modulation signal included in the received signal 152, and outputs the received data 154.

[0049] The data analysis unit 155 takes the received data 154 as an input, analyzes the received data 154, and outputs information 156 including, for example, the location / position of the terminal 150 by estimating the location / position of the terminal 150.

[0050] The display unit 157 takes the information 156 as an input and displays the location / position of the terminal 150 based on the location / position information of the terminal 150 included in the information 156.

[0051] [Frame Configuration] FIG. 7 shows an example of the frame configuration of the modulation signal transmitted by the first device 100.

[0052] In FIG. 7, the horizontal axis represents time. The first device 100 transmits, for example, a preamble 201, and then transmits a control information symbol 202, a symbol 203 related to location information or position information, and a symbol 204 related to time information.

[0053] Preamble 201 is a symbol for a terminal 150 that receives a modulated signal transmitted by a first device 100 to perform, for example, signal detection, time synchronization, frame synchronization, etc.

[0054] The control information symbol 202 is a symbol that contains data such as, for example, the method of configuring the modulated signal, the method of the error correction coding method being used, the frame configuration method, etc.

[0055] The symbol 203 related to location information or position information is a symbol that contains information 101 related to the location or position shown in FIG. 6.

[0056] Note that the frame may contain symbols other than symbols 201, 202, and 203. For example, as shown in FIG. 7, it may contain a symbol 204 related to time information. The symbol 204 related to time information is assumed to contain, for example, information 105 related to the time when the first device 100 transmits the modulated signal. Note that the configuration of the frame of the modulated signal transmitted by the first device 100 is not limited to that in FIG. 7, and the symbols included in the modulated signal are not limited to the configuration in FIG. 7. The frame may contain symbols that include other data / information.

[0057] [Effect] As described with reference to FIGS. 6 and 7, the effect when the first device 100 transmits a modulated signal and the terminal 150 receives the modulated signal will be described.

[0058] Since the first device 100 transmits a modulated signal by visible light, a terminal 150 that can receive this modulated signal is not in a location far from the location where the first device 100 exists. Therefore, by the terminal 150 obtaining the location / position information transmitted by the first device 100, the terminal 150 can easily obtain high-precision position information (without performing complex signal processing).

[0059] Also, if the first device 100 is installed in a place where it is difficult to receive satellite radio waves from GPS, the terminal 150 can safely obtain highly accurate position 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 GPS satellites.

[0060] (Embodiment 2) In this embodiment, a case where there are a plurality of the first devices 100 described in Embodiment 1 will be described.

[0061] In this embodiment, for example, as shown in FIG. 8, a first - 1 device 301 - 1 having the same configuration as the first device 100 shown in FIG. 6 transmits a modulated signal. A terminal 302 having the same configuration as the terminal 150 shown in FIG. 6 receives the modulated signal transmitted by the first - 1 device 301 - 1 and obtains, for example, information regarding the location and position of the first - 1, and information regarding the time of the first - 1.

[0062] Similarly, a first - 2 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 - 2 device 301 - 2 and obtains, for example, information regarding the location and position of the first - 2, and information regarding the time of the first - 2.

[0063] Then, the terminal 302 can calculate the distance between the first - 1 device 301 - 1 and the first - 2 device 301 - 2 in FIG. 8 from the information regarding the location and position of the first - 1 and the information regarding the location and position of the first - 2. Also, the terminal 302 can calculate the distance between the terminal 302 and the first - 1 device 301 - 1 based on the information regarding the time of the first - 1 and, for example, the time when the terminal 302 received the modulated signal transmitted by the first - 1 device 301 - 1. Similarly, the terminal 302 can calculate the distance between the terminal 302 and the first - 2 device 301 - 2 based on the information regarding the time of the first - 2 and, for example, the time when the terminal 302 received the modulated signal transmitted by the first - 2 device 301 - 2.

[0064] Also, the terminal 302 can determine the position of the first device 301-1 from the information regarding the first location. The terminal 302 can determine the position of the second device 301-2 from the information regarding the second location.

[0065] Also, the terminal 302 can identify the triangle formed by the first device 301-1, the second device 301-2, and the terminal 302 from the "distance between the first device 301-1 and the second device 301-2", the "distance between the first device 301-1 and the terminal 302", and the "distance between the second device 301-2 and the terminal 302".

[0066] Therefore, the terminal 302 can accurately calculate and obtain its own position from the "position of the first device 301-1", the "position of the second device 301-2", and the "triangle formed by the first device 301-1, the second device 301-2, and the terminal 302".

[0067] However, the geodetic survey method by which the terminal 302 obtains location information is not limited to the above description, and any method of geodetic survey may be used. For example, examples of geodetic survey methods include triangulation, polygonometry, trilateration, and leveling.

[0068] As described above, in this embodiment, the terminal 302 can accurately estimate its own position by obtaining the above information from a plurality of devices 301 each having a light source that transmits location information.

[0069] Also, in this embodiment, as described in Embodiment 1, when a device 301 having a light source that transmits location information is installed in a location where it is difficult to receive satellite radio waves from GPS, the terminal 302 can safely obtain highly accurate position information by receiving the modulated signal transmitted by the device 301 even in a situation where it is difficult to receive radio waves from GPS satellites.

[0070] In the above example, the case where the terminal 302 receives the modulation signals transmitted by two devices 301 has been described. However, the same can be implemented even when the terminal 302 receives the modulation signals transmitted by more than two devices 301. Note that the larger the number of devices 301, the more advantageous it is that the terminal 302 can calculate the position information with high accuracy.

[0071] (Embodiment 3) FIG. 9 shows an example of the configuration of a device 400, a terminal 450, and a base station 470 (or an AP (access point)) that communicates with the terminal 450 in the present embodiment.

[0072] The device 400 includes, for example, a visible light source such as an LED, lighting, a light source, or a light. Note that hereinafter, the device 400 may also be referred to as the "first device".

[0073] In the first device 400 shown in FIG. 9, the same reference numerals are given to the configurations that operate in the same manner as the first device 100 shown in FIG. 6. Also, in the terminal 450 shown in FIG. 9, the same reference numerals are given to the configurations that operate in the same manner as the terminal 150 shown in FIG. 6.

[0074] In the first device 400 of FIG. 9, the transmission unit 102 takes, for example, information regarding a location or position 101, information 401-1 regarding an SSID (service set identifier) that is an identifier of the base station 470, and information 401-2 regarding an access destination as inputs. The transmission unit 102 may also take information 105 regarding time as an input.

[0075] The transmission unit 102 takes the information regarding a location or position 101, the information 401-1 regarding the SSID, the information 401-2 regarding the access destination, and / or the information 105 regarding time as inputs, and based on these input signals, generates an (optical) modulation signal 103 and outputs the modulation signal 103. Then, the modulation signal 103 is transmitted from, for example, the light source 104.

[0076] Note that since examples of information regarding a location or information regarding a position 101 were described in Embodiment 1, the description thereof is omitted here.

[0077] Next, information 401-1 regarding the SSID and information 401-2 regarding an access destination will be described.

[0078] First, information 401-1 regarding the SSID will be described.

[0079] Information 401-1 regarding the SSID is information indicating the SSID of the base station 470 in FIG. 9. Here, when it is found that the SSID notified by the optical signal is the SSID of a secure base station, the first device 400 can provide access to the base station 470, which is a secure access destination, to the terminal 450. Thereby, the terminal 450 in FIG. 9 can obtain information securely from the base station 470.

[0080] On the other hand, the first device 400 can limit the terminals accessing the base station 470 to the terminals located in a space where the optical signal transmitted (irradiated) by the first device 400 can be received.

[0081] 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. Further, the terminal 450 may separately perform a process of determining whether or not the notified SSID is secure. For example, the first device 400 may include a predetermined identifier in the optical signal and transmit it, and the terminal 450 may determine whether or not the notified SSID is the SSID of a secure base station based on the received identifier. Further, without performing a process of determining whether or not it is a secure base station, the terminal 450 may use the characteristics of visible light to select the first device 400 with high security by the user, receive an optical signal from the first device 400 at the terminal 450, and obtain the SSID of a highly secure base station.

[0082] Note that in FIG. 9, only the base station 470 is shown. However, for example, even when there is one or more other base stations (or APs) other than the base station 470, the terminal 450 will access the base station 470 using the SSID obtained from the first device 400 and obtain information.

[0083] Next, the information 401-2 regarding the access destination will be described.

[0084] The information 401-2 regarding the access destination is information regarding the access destination for obtaining information after the terminal 450 accesses the base station 470. Specific operation examples of this embodiment will be described later.

[0085] Above, the information 401-1 regarding the SSID and the information 401-2 regarding the access destination have been described.

[0086] The terminal 450 receives the modulated signal 103 transmitted from the first device 400.

[0087] 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 the modulated signal transmitted from the first device 400 and outputs a received signal 152.

[0088] Then, the receiving unit 153 takes the received signal 152 received by the light receiving unit 151 as an 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.

[0089] The data analysis unit 155 takes the received data 154 as an input and estimates, for example, the location and position of the terminal 450 from the received data 154. Then, the data analysis unit 155 outputs information 156 including at least the location and position information of the terminal 450, information 451 regarding the SSID, and information 452 regarding the access destination.

[0090] The display unit 157 takes as input information 156 including the location and position information of the terminal 450, information 451 regarding the SSID, and information 452 regarding the access destination, and displays, for example, the location and position of the terminal 450, the SSID of the communication partner accessed by the wireless device 453 included in the terminal 450, and / or the access destination (hereinafter, this display is referred to as the "first display").

[0091] For example, after the first display, the wireless device 453 takes as input information 451 regarding the SSID and information 452 regarding the access destination. Then, based on the information 451 regarding the SSID, the wireless device 453 connects to the communication partner, for example, by using radio waves. In the case of FIG. 9, the wireless device 453 will be connected to the base station 470.

[0092] Then, based on the information 452 regarding the access destination, the wireless device 453 generates a modulation signal from the data including the information regarding the access destination, and transmits this modulation signal to the base station 470, for example, using radio waves.

[0093] In FIG. 9, the base station 470, which is the communication partner of the terminal 450, receives the modulation signal transmitted by the wireless device 453 included in the terminal 450.

[0094] Then, the base station 470 performs processes such as demodulation of the received modulation signal and error correction decoding, and outputs received data 471 including the information of the access destination transmitted from the terminal 450. Based on this information of the access destination, the base station 470 accesses the desired access destination via the network, and for example, obtains the desired information 472 from the access destination. Then, taking the desired information 472 as input, the base station 470 generates a modulation signal from the desired information 472, and transmits this modulation signal to the terminal 450 (wireless device 453), for example, using radio waves.

[0095] The wireless device 453 of the terminal 450 receives the modulation signal transmitted from the base station 470, performs processes such as demodulation and error correction decoding, and obtains the desired information 472.

[0096] For example, assume that the desired information 472 is information such as "area, seat, store, facility" information in a map, a building map / floor guide, a facility map / floor guide, a parking lot map / floor guide, a concert facility / stadium / airplane / airport lounge / railway / station, etc.

[0097] The display unit 157 takes as input information 454 including the desired information 472, information 156 including at least the location / position information of the terminal 450, and information 451 regarding the SSID. After the first display, from the desired information 472 and the information 156 including at least the location / position information of the terminal 450, it performs a display in which the position of the terminal 450 is mapped on the display of map / floor guide / facility information / seat information / store information.

[0098] Figure 10 is an example of a specific display of the display unit 157.

[0099] The display in Figure 10 indicates that it is the "third floor". And A-1, A-2, A-3, A-4, A-21, A-22, A-23, A-24 respectively indicate the positions of the car parking spaces. Also, a-1, a-2 indicate the positions of the elevators. The map information including the positions of this parking space and elevator is an example of the desired information 454(472).

[0100] As shown in Figure 10, the display unit 157 maps and displays the current position of the terminal 450 on the map. Note that the current position is information obtained from the information 156 including at least the location / position information of the terminal 450.

[0101] Figure 11 shows an example of the frame configuration of the modulation signal transmitted by the first device 400 shown in Figure 9. In Figure 11, the horizontal axis is time. Also, in Figure 11, symbols that transmit the same information as in Figure 7 are given the same reference numerals, and their descriptions are omitted.

[0102] The first device 400 transmits, in addition to the preamble 201, the control information symbol 202, the symbol 203 related to location information or position information, and the symbol 204 related to time information, the symbol 600-1 related to the SSID and the symbol 600-2 related to the access destination.

[0103] The symbol 600-1 related to the SSID is a symbol for transmitting the information 401-1 related to the SSID in FIG. 9, and the symbol 600-2 related to the access destination is a symbol for transmitting the information 401-2 related to the access destination in FIG. 9. Note that, in the frame of FIG. 11, symbols other than the symbols described in FIG. 11 may be included. Also, the frame configuration, including the order in which the symbols are transmitted, is not limited to the configuration of FIG. 11.

[0104] FIG. 12 shows an example of the frame configuration of the modulation signal transmitted by the base station 470 shown in FIG. 9. In FIG. 12, the horizontal axis represents time.

[0105] As shown in FIG. 12, the base station 470 transmits, for example, the preamble 701, and then transmits the control information symbol 702 and the information symbol 703.

[0106] The preamble 701 is a symbol for a terminal 450 that receives the modulation signal transmitted by the base station 470 to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, and the like.

[0107] The control information symbol 702 is a symbol including data such as the method of the error correction coding method, information related to the modulation method, and information related to the frame configuration, which are used to generate the modulation signal. The wireless device 453 of the terminal 450 performs demodulation of the modulation signal based on the information of the control information symbol 702.

[0108] The information symbol 703 is a symbol for transmitting information. In the case of this embodiment, the information symbol 703 is a symbol for transmitting the desired information 472 described above.

[0109] Note that the base station 470 shown in FIG. 9 may transmit a frame including symbols other than the symbols described in FIG. 12. For example, the base station 470 may transmit a frame including a pilot symbol (reference symbol) in the middle of the information symbol 703. Further, the frame configuration is not limited to the configuration of FIG. 12, including the order in which the symbols are transmitted. Also, in FIG. 12, a plurality of symbols may exist in the frequency axis direction. That is, in FIG. 12, symbols may exist on a plurality of frequencies (a plurality of carriers).

[0110] Also, for example, a modulation signal having the frame configuration shown in FIG. 11 transmitted by the first device 400 may be transmitted at regular timing, for example, repeatedly. Thereby, a plurality of terminals 450 can perform the operations as described above.

[0111] 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.

[0112] First, the first device 400 transmits a modulation signal having the frame configuration shown in FIG. 11 (ST801).

[0113] Then, the terminal 450 receives the modulation signal transmitted by the first device 400 and estimates the location / position of the terminal 450 (ST802).

[0114] In addition, the terminal 450 receives the modulation signal transmitted by the first device 400 and grasps the SSID of the base station 470 to which the terminal 450 accesses (ST803).

[0115] Then, the terminal 450 transmits a modulation signal including data including information 452 regarding an access destination for obtaining information such as a map to the base station 470 using, for example, radio waves (ST804).

[0116] The base station 470 receives the modulated signal transmitted by the terminal 450, obtains the information of the access destination, accesses the desired access destination via the network, and obtains desired information such as a map (information to be transmitted to the terminal 450) (ST805).

[0117] Then, the base station 470 transmits the modulated signal including the desired information such as the obtained map to the terminal 450 using, for example, radio waves (ST806).

[0118] The terminal 450 receives the modulated signal transmitted by the base station 470 and obtains information such as a map. Then, the terminal 450 performs a display as shown in FIG. 10 based on the information such as the map and the location / position information of the terminal 450 that it already has obtained.

[0119] Next, an operation example when a plurality of first devices 400 and the base station 470 are installed at the location shown in FIG. 10 will be described.

[0120] FIG. 14 shows a map of the same location as FIG. 10. That is, FIG. 14 is a map of the "third floor" as described in FIG. 10. In FIG. 14, A-1, A-2, A-3, A-4, A-21, A-22, A-23, A-24 indicate parking spaces for vehicles, and a-1, a-2 indicate elevators.

[0121] Also, a first device having the same configuration as the first device 400 shown in FIG. 9 is installed at the position of "○" 901-1 in FIG. 14. Hereinafter, the first device having the same configuration as the first device 400 installed at the position of 901-1 is referred to as the "first-1 device 400". The first-1 device 400 has information "A-1" as information regarding a location or a position, and transmits the information "A-1".

[0122] Install a first device having the same configuration as the first device 400 in FIG. 9 at the position of "○" 901-2 in FIG. 14. Hereinafter, the first device having the same configuration as the first device 400 installed at the position of 901-2 is referred to as the "first-2 device 400". The first-2 device 400 has information "A-2" as information regarding location or position, and transmits the information "A-2".

[0123] Install a first device having the same configuration as the first device 400 in FIG. 9 at the position of "○" 901-3 in FIG. 14. Hereinafter, the first device having the same configuration as the first device 400 installed at the position of 901-3 is referred to as the "first-3 device 400". The first-3 device 400 has information "A-3" as information regarding location or position, and transmits the information "A-3".

[0124] Install a first device having the same configuration as the first device 400 in FIG. 9 at the position of "○" 901-4 in FIG. 14. Hereinafter, the first device having the same configuration as the first device 400 installed at the position of 901-4 is referred to as the "first-4 device 400". The first-4 device 400 has information "A-4" as information regarding location or position, and transmits the information "A-4".

[0125] Install a first device having the same configuration as the first device 400 in FIG. 9 at the position of "○" 901-21 in FIG. 14. Hereinafter, the first device having the same configuration as the first device 400 installed at the position of 901-21 is referred to as the "first-21 device 400". The first-21 device 400 has information "A-21" as information regarding location or position, and transmits the information "A-21".

[0126] Install a first device having the same configuration as the first device 400 in FIG. 9 at the position of "○" 901-22 in FIG. 14. Hereinafter, the first device having the same configuration as the first device 400 installed at the position of 901-22 is referred to as the "first-22 device 400". The first-22 device 400 has information "A-22" as information regarding location or position, and transmits the information "A-22".

[0127] Install a first device having the same configuration as the first device 400 in FIG. 9 at the position of "○" 901-23 in FIG. 14. Hereinafter, the first device having the same configuration as the first device 400 installed at the position of 901-23 is referred to as the "first-23 device 400". The first-23 device 400 has information "A-23" as information regarding location or position, and transmits the information "A-23".

[0128] Install a first device having the same configuration as the first device 400 in FIG. 9 at the position of "○" 901-24 in FIG. 14. Hereinafter, the first device having the same configuration as the first device 400 installed at the position of 901-24 is referred to as the "first-24 device 400". The first-24 device 400 has information "A-24" as information regarding location or position, and transmits the information "A-24".

[0129] Also, install a base station (or AP) having the same configuration as the base station 470 in FIG. 9 at the position of "◎" 902 in FIG. 14. Hereinafter, the base station (or AP) having the same configuration as the base station 470 in FIG. 9 is simply referred to as the "base station 470". Also, here, the SSID of the base station 470 installed at the position of 902 is set to "abcdef".

[0130] When the terminal 450 existing around the position shown in the map of FIG. 14 performs wireless communication, it may access the base station 470 installed at the position of 902 in FIG. 14.

[0131] Therefore, the "First Device 400" installed at 901-1 in FIG. 14 transmits "abcdef" as information regarding the SSID (see 401-1 in FIG. 9).

[0132] Similarly, the "First Device 400" installed at 901-2 in FIG. 14 transmits "abcdef" as information regarding the SSID (see 401-1 in FIG. 9).

[0133] The "First Device 400" installed at 901-3 in FIG. 14 transmits "abcdef" as information regarding the SSID (see 401-1 in FIG. 9).

[0134] The "First Device 400" installed at 901-4 in FIG. 14 transmits "abcdef" as information regarding the SSID (see 401-1 in FIG. 9).

[0135] The "First Device 400" installed at 901-21 in FIG. 14 transmits "abcdef" as information regarding the SSID (see 401-1 in FIG. 9).

[0136] The "First Device 400" installed at 901-22 in FIG. 14 transmits "abcdef" as information regarding the SSID (see 401-1 in FIG. 9).

[0137] The "First Device 400" installed at 901-23 in FIG. 14 transmits "abcdef" as information regarding the SSID (see 401-1 in FIG. 9).

[0138] The "First Device 400" installed at 901-24 in FIG. 14 transmits "abcdef" as information regarding the SSID (see 401-1 in FIG. 9).

[0139] Hereinafter, specific operation examples will be described.

[0140] Assume that there is a terminal (hereinafter simply referred to as "terminal 450") having the same configuration as terminal 450 in FIG. 9 at the position of 903-1 in FIG. 14. In this case, terminal 450 receives the modulated signal transmitted by "Device 400 of 1-4" located at the position of 901-4 in FIG. 14 and obtains the position information of "A-4". Also, terminal 450 receives the modulated signal transmitted by "Device 400 of 1-4" located at the position of 901-4 in FIG. 14 and obtains the SSID information of "abcdef". As a result, terminal 450 will access the base station 470 located at 902 in FIG. 14. Further, terminal 450 obtains information such as a map from the base station 470 located at 902 in FIG. 14. Then, terminal 450 displays the map information and the position information (see FIG. 10 for example. However, FIG. 10 is merely an example of the display).

[0141] Similarly, assume that there is a terminal (hereinafter simply referred to as "terminal 450") having the same configuration as terminal 450 in FIG. 9 at the position of 903-2 in FIG. 14. In this case, terminal 450 receives the modulated signal transmitted by "Device 400 of 1-22" located at the position of 901-22 in FIG. 14 and obtains the position information of "A-22". Also, terminal 450 receives the modulated signal transmitted by "Device 400 of 1-4" located at the position of 901-22 in FIG. 14 and obtains the SSID information of "abcdef". As a result, terminal 450 will access the base station 470 located at 902 in FIG. 14. Further, terminal 450 obtains information such as a map from the base station 470 located at 902 in FIG. 14. Then, terminal 450 displays the map information and the position information (see FIG. 10 for example. However, FIG. 10 is merely an example of the display).

[0142] Note that terminal 450 may record the map (surrounding information) and the position information as shown in FIG. 14 in a storage unit (not shown) provided in terminal 450 so that the user using terminal 450 can retrieve the information recorded in the storage unit when needed. Thereby, the user can utilize the map (surrounding information) and the position information more conveniently.

[0143] As described above, since the first device 400 transmits a modulation signal by visible light, the terminal 450 that can receive this modulation signal is limited to within a range where it can receive an optical signal from the position of the first device 400. Therefore, by the terminal 450 receiving the location and position information transmitted by the first device 400, the terminal 450 can easily obtain high-precision position information (without complex signal processing).

[0144] Also, when the first device 400 is installed in a place where it is difficult to receive satellite radio waves from GPS, the terminal 450 can safely obtain high-precision position information by receiving the modulation signal transmitted by the first device 400 even in a situation where it is difficult to receive radio waves from GPS satellites.

[0145] Furthermore, based on the SSID information transmitted from the first device 400, when the terminal 450 connects to the base station (or AP) 470 to obtain information, the terminal 450 can safely obtain the information. This is because when the terminal 450 obtains information from the modulation signal of visible light, since it is visible light, the user can easily recognize the first device 400 that transmitted the modulation signal visually or the like, and it is easy to determine whether the information source is safe. In contrast, for example, when the SSID is obtained from the modulation signal of the radio wave transmitted by a wireless LAN, it is difficult for the user to identify the device that transmitted the radio wave. Therefore, in terms of ensuring information security, visible light communication is more suitable for obtaining the SSID compared to wireless LAN communication.

[0146] Note that a plurality of additional signals may be input to the wireless device 453 of the terminal 450 in FIG. 9. For example, a control signal for controlling the wireless device 453 and information to be transmitted to the base station 470 may be input to the wireless device 453. At this time, an operation where the wireless device 453 starts communication based on the control signal can be considered as an example. As described above, in this embodiment, the configuration of the first device is not limited to the configuration of the first device 400 in FIG. 9, the configuration of the terminal is not limited to the configuration of the terminal 450 in FIG. 9, and the connection destination and configuration of the base station are also not limited to the connection destination and configuration of the base station 470 shown in FIG. 9.

[0147] Also, in FIG. 9, the case where one base station 470 is arranged is described, but there may be a plurality of base stations (or APs) to which the terminal 450 can access (safely). At this time, the symbol regarding the SSID transmitted by the first device 400 in FIG. 9 may include information indicating the SSIDs of these plurality of base stations (or APs). In this case, on the display unit 157 of the terminal 450 in FIG. 9, as the display of the access destination (the above-described "first display"), a list of the SSIDs of the plurality of base stations and / or a list of the plurality of access destinations are displayed. Then, the terminal 450 in FIG. 9 may select one or more base stations to actually perform wireless connection based on the SSID information of the plurality of base stations (or APs) (that is, it may be connected to a plurality of base stations simultaneously).

[0148] For example, assume that three base stations 470 are arranged. Here, the three base stations 470 are referred to as base station #A, base station #B, and base station #C, respectively. Also, assume 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". In this case, the symbol 600-1 regarding the SSID in the frame configuration shown in FIG. 11 of the modulation signal transmitted by the first device 400 includes 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"". Then, the terminal 450 in FIG. 9 receives the symbol 600-1 regarding the SSID and selects one or more base stations 470 to actually perform wireless connection based on the information of "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"".

[0149] (Embodiment 4) FIG. 15 is a diagram showing an example of the configuration of the communication system in the present embodiment.

[0150] The communication system of FIG. 15 includes, for example, a device 1000, a terminal 1050, and a base station (or AP) 470 that communicates with the terminal 1050.

[0151] The device 1000 includes, for example, a visible light source such as an LED, lighting, a light source, a light (hereinafter referred to as the light source 104). In the following, the device 1000 may also be referred to as the "second device" in the present embodiment.

[0152] 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 given the same numbers. Also, in the terminal 1050 shown in FIG. 15, components that operate in the same manner as the terminal 150 shown in FIG. 6 are given the same numbers. Further, the communication between the wireless device 453 of the terminal 1050 shown in FIG. 15 and the base station 470 uses, for example, radio waves.

[0153] In the second device 1000 of FIG. 15, the transmission unit 102 takes information 1001-1 regarding the SSID, information 1001-2 regarding the encryption key, and data 1002 as inputs, and based on these input signals, generates a (light) modulation signal 103 and outputs the modulation signal 103. Then, the modulation signal 103 is transmitted from, for example, the light source 104.

[0154] Next, the information 1001-1 regarding the SSID and the information 1001-2 regarding the encryption key will be described.

[0155] First, the information 1001-1 regarding the SSID will be described.

[0156] The information 1001-1 regarding the SSID is information indicating the SSID of the base station 470 in FIG. 15. As an example, the base station 470 transmits the modulation signal to the terminal 1050 by radio waves and receives the modulation signal from the terminal 1050 by radio waves. That is, the second device 1000 can provide access to the base station 470, which is a secure access destination for the terminal 1050. Thereby, the terminal 1050 in FIG. 15 can obtain information securely from the base station 470.

[0157] On the other hand, the second device 1000 can limit the terminals accessing the base station 470 to the terminals located in a space where the optical signal transmitted (irradiated) by the second device 1000 can be received.

[0158] In addition, when the 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. Alternatively, the terminal 1050 may separately perform a process of determining whether the notified SSID is secure. For example, the second device 1000 includes a predetermined identifier in the optical signal and transmits it, and the terminal 1050 may determine whether the notified SSID is the SSID of a secure base station based on the received identifier.

[0159] Note that in FIG. 15, only the base station 470 is shown. However, for example, when there are base stations (or APs) other than the base station 470, the terminal 1050 accesses the base station 470 using the SSID acquired from the second device 1000 and obtains information.

[0160] Next, the information 1001-2 regarding the encryption key will be described.

[0161] The information 1001-2 regarding the encryption key is information regarding the encryption key required for the terminal 1050 to communicate with the base station 470. By obtaining the information 1001-2 regarding the encryption key from the second device 1000, the terminal 1050 can perform encrypted communication with the base station 470.

[0162] As described above, the information 1001-1 regarding the SSID and the information 1001-2 regarding the encryption key have been described.

[0163] The terminal 1050 in FIG. 15 receives the modulated signal transmitted by the second device 1000. Note that for the components in the terminal 1050 in FIG. 15 that operate in the same manner as the terminal 150 in FIG. 6 and the terminal 450 in FIG. 9, the same numbers are assigned.

[0164] The light receiving unit 151 included in the terminal 1050 is an image sensor such as a CMOS or an organic CMOS, for example. The light receiving unit 151 receives light including the modulation signal transmitted from the second device 1000 and outputs a received signal 152.

[0165] Then, the receiving unit 153 takes the received signal 152 received by the light receiving unit 151 as an input, performs processes such as demodulation and error correction decoding on the modulation signal included in the received signal 152, and outputs received data 154.

[0166] The data analysis unit 155 takes the received data 154 as an input and outputs, for example, information 1051 on the SSID of the base station to be connected and information 1052 on the encryption key for communicating with the base station to be connected from the received data 154. For example, in a wireless LAN (Local Area Network), as encryption methods, there are 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). Note that the encryption method is not limited to this.

[0167] The display unit 157 takes the SSID information 1051 and the encryption key information 1052 as inputs and displays, for example, the SSID of the communication partner accessed by the wireless device 453 included in the terminal 1050 and the encryption key (this display is referred to as the "first display" in the present embodiment).

[0168] For example, after the first display, the wireless device 453 takes the SSID information 1051 and the encryption key information 1052 as inputs and establishes a connection with the base station 470 (for example, assume the connection uses radio waves). At this time, when the base station 470 also communicates with the wireless device 453 included in the terminal 1050, it transmits a modulation signal using, for example, radio waves.

[0169] After that, the wireless device 453 takes the data 1053 and the control signal 1054 as inputs, performs modulation on the data 1053 according to the control indicated by the control signal 1054, and transmits the modulation signal by radio waves.

[0170] Then, for example, the base station 470 transmits data (471) to the network and receives data (472) from the network. After that, for example, the base station 470 transmits the modulation signal to the terminal 1050 by radio waves.

[0171] The wireless device 453 included in the terminal 1050 performs processes such as demodulation and error correction decoding on the modulation signal received by radio waves, and obtains the received data 1056. The display unit 157 performs display based on the received data 1056.

[0172] FIG. 16 shows an example of the frame configuration of the modulation signal transmitted by the second device 1000 shown in FIG. 15. In FIG. 16, the horizontal axis represents time. Also, in FIG. 16, the same symbols as those in FIGS. 7 and 11 are given the same numbers, and their descriptions are omitted.

[0173] The symbol 600-1 related to the SSID is a symbol for transmitting the information 1001-1 related to the SSID in FIG. 15, and the symbol 1101 related to the encryption key is a symbol for transmitting the information 1001-2 related to the encryption key in FIG. 15. The data symbol 1102 is a symbol for transmitting the data 1002 in FIG. 15.

[0174] The second device 1000 transmits the preamble 201, the control information symbol 202, the symbol 600-1 related to the SSID, the symbol 1101 related to the encryption key, and the data symbol 1102. Note that the second device 1000 may transmit a frame including symbols other than those described in FIG. 16. Also, the frame configuration is not limited to the configuration of FIG. 16, including the order of transmitting the symbols.

[0175] FIG. 17 shows an example of the frame configuration of the modulation signal transmitted by the wireless device 453 included in the terminal 1050 of FIG. 15. In FIG. 17, the horizontal axis represents time.

[0176] As shown in FIG. 17, the wireless device 453 included in the terminal 1050 transmits, for example, a preamble 1201, and then transmits a control information symbol 1202 and an information symbol 1203.

[0177] The preamble 1201 is a symbol used by the base station 470 that receives the modulation signal transmitted by the wireless device 453 of the terminal 1050 to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, and the like.

[0178] The control information symbol 1202 is a symbol that includes data such as, for example, the method of error correction coding used to generate the modulation signal, information regarding the modulation method, information regarding the frame configuration, and information regarding the transmission method. The base station 470 performs demodulation of the modulation signal and the like based on the information included in the control information symbol 1202.

[0179] The information symbol 1203 is a symbol for the wireless device 453 of the terminal 1050 to transmit data.

[0180] Note that the wireless device 453 of the terminal 1050 may transmit a frame including symbols other than those described in FIG. 17. For example, the wireless device 453 may transmit a frame including a pilot symbol (reference symbol) in the middle of the information symbol 1203. Also, the frame configuration is not limited to the configuration of FIG. 17, including the order in which the symbols are transmitted. Further, in FIG. 17, a plurality of symbols may exist in the frequency axis direction. That is, in FIG. 17, symbols may exist at a plurality of frequencies (a plurality of carriers). Also, in Embodiment 3, when the wireless device 453 included in the terminal 450 of FIG. 9 transmits a modulation signal, the frame configuration of FIG. 17 may be used.

[0181] The frame configuration of the modulation signal transmitted by the base station 470 in this embodiment is the same as the frame configuration of FIG. 12 described in Embodiment 3. That is, as shown in FIG. 12, the base station 470 transmits, for example, a preamble 701, and then transmits a control information symbol 702 and an information symbol 703.

[0182] The preamble 701 is a symbol for the radio device 453 of the terminal 1050 that receives the modulation signal transmitted by the base station 470 to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, and the like.

[0183] The control information symbol 702 is a symbol that contains data such as, for example, the method of error correction coding, information on the modulation method, information on the frame configuration, and information on the transmission method used to generate the modulation signal. The radio device 453 of the terminal 1050 performs demodulation of the modulation signal based on the information of the control information symbol 702.

[0184] The information symbol 703 is a symbol for the base station 470 to transmit data.

[0185] Note that the base station 470 shown in FIG. 15 may transmit a frame including symbols other than the symbols described in FIG. 12. For example, the base station 470 may transmit a frame including a pilot symbol (reference symbol) in the middle of the information symbol 703. Also, the frame configuration is not limited to the configuration of FIG. 12, including the order in which the symbols are transmitted. Also, in FIG. 12, a plurality of symbols may exist in the frequency axis direction. That is, in FIG. 12, symbols may exist on a plurality of frequencies (a plurality of carriers).

[0186] Also, for example, the modulation signal having the frame configuration of FIG. 16 transmitted by the second device 1000 may be transmitted at regular timings, for example, repeatedly. Thereby, a plurality of terminals 1050 can perform the operations as described above.

[0187] FIG. 18 is a flowchart showing an example of the processes performed by the "second device 1000", "terminal 1050", and "base station 470" shown in FIG. 15.

[0188] First, the second device 1000 transmits a modulated signal having the frame configuration shown in FIG. 16 (ST1301).

[0189] Then, the terminal 1050 receives the modulated signal transmitted by the second device 1000 and acquires the SSID of the base station 470 to which the terminal 1050 is to connect (ST1302).

[0190] In addition, the terminal 1050 acquires an encryption key used for communication with the base station 470 to which the terminal 1050 is to connect (ST1303).

[0191] Then, the terminal 1050 establishes a radio connection with the base station 470 (ST1304). When the terminal 1050 receives a response from the base station 470, the connection with the base station 470 is completed (ST1305).

[0192] Then, the terminal 1050 transmits connection destination information to the base station 470 using radio waves (ST1306).

[0193] The base station 470 obtains information to be transmitted to the terminal 1050 from the network (ST1307).

[0194] Then, the base station 470 transmits the obtained information to the terminal 1050 using radio waves, and the terminal 1050 obtains the information (ST1308). The terminal 1050 acquires necessary information from the network via the base station 470, for example, when necessary.

[0195] As described above, based on the SSID information and encryption key information transmitted from the second device 1000, the terminal 1050 can connect to the base station 470 and obtain information, thereby safely obtaining information via the base station 470 with guaranteed security. This is because when the terminal 1050 obtains information from the modulation signal of visible light, since it is visible light, it is easy for the user to determine whether the information source is secure. On the other hand, for example, when the SSID is obtained from the modulation signal of the radio wave transmitted by the wireless LAN, it is difficult for the user to identify the device that transmitted the radio wave. Therefore, in terms of ensuring information security, visible light communication is more suitable for obtaining the SSID compared to wireless LAN communication.

[0196] In addition, in this embodiment, the case where the second device 1000 transmits the encryption key information has been described. However, for example, when the base station 470 is not performing encrypted communication using the encryption key, the second device 1000 may not transmit the encryption key information and may only transmit information regarding the SSID. In this case, in the above-described configuration, it can be similarly implemented by simply deleting the configuration related to the encryption key.

[0197] Also, 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.

[0198] Also, in FIG. 15, the case where one base station 470 is arranged is described, but there may be a plurality of base stations (or APs) to which the terminal 1050 can access (safely). Note that these plurality of base stations and the terminal 1050 will each perform transmission and reception of a modulated signal using radio waves. At this time, the symbol regarding the SSID transmitted by the second device 1000 in FIG. 15 may include information on the SSIDs of these plurality of base stations (or APs). In this case, on the display unit 157 of the terminal 1050 in FIG. 15, as a display of the access destination, a list of the SSIDs of the plurality of base stations and / or a list of the plurality of access destinations is displayed. Also, the symbol regarding the encryption key transmitted by the second device 1000 in FIG. 15 may include information on the encryption keys used to connect to each of these plurality of base stations (or APs). Then, the terminal 1050 in FIG. 15 may select one or more base stations to actually wirelessly connect to (for example, by radio waves) based on the information on the SSIDs of the plurality of base stations and the information on the encryption keys (that is, it may connect to a plurality of base stations simultaneously).

[0199] For example, assume that three base stations 470 are arranged. Here, the three base stations 470 are respectively called base station #A, base station #B, and base station #C. 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".

[0200] In this case, the symbol 600-1 regarding the SSID in the frame configuration of FIG. 16 of the modulation signal transmitted by the second device 1000 includes 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"". Also, the symbol 1101 regarding the encryption key in the frame configuration of FIG. 16 includes 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"".

[0201] Then, the terminal 1050 in FIG. 15 receives the symbol 600-1 regarding the SSID and obtains the information of "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, the terminal 1050 receives the symbol 1101 regarding the encryption key and obtains the information regarding "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, the terminal 1050 selects and connects to one or more base stations for actual wireless connection (for example, by radio waves).

[0202] Also, as in this embodiment, by using a light source such as an LED as an example to set the base station 470 accessed by the terminal 1050, a special setting mode for performing procedures for connection of wireless communication between the terminal 1050 and the base station 470 is not required for the modulation signal for wireless transmission transmitted by the terminal 1050. Also, a special setting mode for performing procedures for connection of wireless communication between the terminal 1050 and the base station 470 is not required for the modulation signal transmitted by the base station 470. Therefore, in this embodiment, the data transmission efficiency of wireless communication can be improved.

[0203] Also, the encryption key may be an encryption key for the SSID of the wireless LAN as described above, or may be an encryption key for restricting the connection form, service form, network connection range, etc. That is, an encryption key may be introduced for some kind of restriction.

[0204] (Embodiment 5) FIG. 19 is a diagram showing an example of the configuration of the communication system in the present embodiment.

[0205] The communication system in FIG. 19 includes, for example, devices 1400A and 1400B, terminal 1050, and a base station (or AP) 470 that communicates with terminal 1050.

[0206] Devices 1400A and 1400B are equipped with visible light sources such as LEDs, lighting, light sources, lights (hereinafter referred to as light sources 1406-1 and 1406-2). In the following, device 1400A is referred to as the "third device" in the present embodiment, and device 1400B is referred to as the "fourth device" in the present embodiment.

[0207] In the terminal 1050 shown in FIG. 19, components that operate in the same manner as the terminal 150 shown in FIG. 1 or the terminal 1050 shown in FIG. 15 are given the same numbers. Also, for the base station (or AP) 470 shown in FIG. 19, components that operate in the same manner as the base station 470 shown in FIG. 9 are given the same numbers as in FIG. 9. Also, the communication between the wireless device 453 of the terminal 1050 shown in FIG. 19 and the base station 470 uses, for example, radio waves.

[0208] In the third device 1400A of FIG. 19, the transmission unit 1404-1 takes the information 1401-1 regarding the SSID and the data 1402-1 as inputs, generates an (optical) modulation signal 1405-1 based on these input signals, and outputs the modulation signal 1405-1. Then, the modulation signal 1405-1 is transmitted from the light source 1406-1, for example.

[0209] In the fourth device 1400B of FIG. 19, the transmission unit 1404-2 takes information 1403-2 regarding the encryption key and data 1402-2 as inputs, and based on these input signals, generates a (light) modulation signal 1405-2 and outputs the modulation signal 1405-2. Then, the modulation signal 1405-2 is transmitted from, for example, a light source 1406-2.

[0210] Next, information 1401-1 regarding the SSID and information 1403-2 regarding the encryption key will be described.

[0211] First, information 1401-1 regarding the SSID will be described.

[0212] Information 1401-1 regarding the SSID is information indicating the SSID of the base station 470 in FIG. 19. That is, the third device 1400A can provide the terminal 1050 with access to the base station 470, which is a secure access destination by radio waves. As a result, the terminal 1050 in FIG. 19 can safely obtain information from the base station 470.

[0213] Note that when the 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. Also, the terminal 1050 may separately perform a process of determining whether the notified SSID is secure. For example, the third device 1400A may include a predetermined identifier in the optical signal, and the terminal 1050 may determine whether the notified SSID is the SSID of a secure base station based on the received identifier.

[0214] Note that in FIG. 19, only the base station 470 is shown. However, for example, even if there are base stations (or APs) other than the base station 470, the terminal 1050 will access the base station 470 using the SSID obtained from the third device 1400A and the encryption key obtained from the fourth device 1400B and obtain information.

[0215] Next, information 1403-2 regarding the encryption key will be described.

[0216] The information 1403-2 regarding the encryption key is information regarding the encryption key necessary for the terminal 1050 to communicate with the base station 470 via radio waves. By obtaining the information 1403-2 regarding the encryption key from the fourth device 1400B, the terminal 1050 can perform encrypted communication with the base station 470.

[0217] As described above, the information 1401-1 regarding the SSID and the information 1403-2 regarding the encryption key have been explained.

[0218] The terminal 1050 in FIG. 19 receives the modulated signal transmitted by the third device 1400A.

[0219] 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 the light including the modulated signal transmitted from the third device 1400A and outputs a received signal 152.

[0220] Then, the receiving unit 153 takes the received signal 152 received by the light receiving unit 151 as an 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.

[0221] The data analysis unit 155 takes the received data 154 as an input and outputs, for example, information 1051 of the SSID of the base station to be connected from the received data. The wireless device 453 will obtain the information of the SSID of the base station 470 to which the wireless device 453 connects via radio waves from the SSID information 1051.

[0222] The terminal 1050 in FIG. 19 receives the modulated signal transmitted by the fourth device 1400B.

[0223] 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 the light including the modulated signal transmitted from the fourth device 1400B and outputs a received signal 152.

[0224] Then, the receiving unit 153 takes the received signal 152 received by the light receiving unit 151 as an input, performs processes such as demodulation and error correction decoding on the modulation signal included in the received signal 152, and outputs received data 154.

[0225] The data analysis unit 155 takes the received data 154 as an input, and outputs information 1052 of an encryption key for communicating with, for example, the base station to be connected, from the received data. For example, in a wireless LAN (Local Area Network), as encryption methods, there are 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). Note that the encryption method is not limited to this.

[0226] The wireless device 453 included in the terminal 1050 obtains the information of the encryption key of the base station 470 to which the wireless device 453 connects, from the information 1052 of the encryption key for communicating with the base station to be connected (for example, by radio waves).

[0227] The display unit 157 takes the SSID information 1051 and the encryption key information 1052 as inputs, and displays, for example, the SSID of the communication partner accessed by the wireless device 453 included in the terminal 1050, and the encryption key (this display is referred to as the "first display" in the present embodiment).

[0228] For example, after the first display, the wireless device 453 takes the SSID information 1051 and the encryption key information 1052 as inputs, and establishes a radio wave connection with the base station 470. At this time, when the base station 470 also communicates with the wireless device 453 included in the terminal 1050, it transmits a modulation signal using, for example, radio waves.

[0229] After that, the wireless device 453 takes the data 1053 and the control signal 1054 as inputs, modulates the data 1053 according to the control indicated by the control signal 1054, and transmits the modulated signal by radio waves.

[0230] Then, for example, the base station 470 transmits data (471) to the network and receives data (472) from the network. After that, for example, the base station 470 transmits the modulated signal to the terminal 1050 by radio waves.

[0231] The wireless device 453 included in the terminal 1050 performs processes such as demodulation and error correction decoding on the modulated signal received by radio waves, and obtains the received data 1056. The display unit 157 performs display based on the received data 1056.

[0232] FIG. 20 shows an example of the frame configuration of the modulated signal transmitted by the third device 1400A shown in FIG. 19. In FIG. 20, the horizontal axis represents time. Also, in FIG. 20, the same symbols as those in FIGS. 2, 11, and 16 are denoted by the same reference numerals, and the description thereof is omitted.

[0233] The symbol 600-1 related to the SSID is a symbol for transmitting the information 1401-1 related to the SSID in FIG. 19. The data symbol 1102 is a symbol for transmitting the data 1402-1.

[0234] The third device 1400A transmits the preamble 201, the control information symbol 202, the symbol 600-1 related to the SSID, and the data symbol 1102. Note that the third device 1400A may transmit a frame including symbols other than those described in FIG. 20. Also, the frame configuration is not limited to the configuration of FIG. 20, including the order of transmitting the symbols.

[0235] FIG. 21 shows an example of the frame configuration of the modulation signal transmitted by the fourth device 1400B in FIG. 19. In FIG. 21, the horizontal axis represents time. Also, in FIG. 21, the same symbols as those in FIGS. 7 and 16 are denoted by the same reference numerals, and the description thereof is omitted.

[0236] The symbol 1101 regarding the encryption key is a symbol for transmitting the information 1403-2 regarding the encryption key in FIG. 19. The data symbol 1102 is a symbol for transmitting the data 1402-2.

[0237] The fourth device 1400B transmits the preamble 201, the control information symbol 202, the symbol 1101 regarding the encryption key, and the data symbol 1102. Note that the fourth device 1400B in FIG. 19 may transmit a frame including symbols other than the symbols described in FIG. 21. Also, the frame configuration is not limited to that in FIG. 21, including the order in which the symbols are transmitted.

[0238] The frame configuration of the modulation signal transmitted by the wireless device 453 in the present embodiment is the same as the frame configuration in FIG. 17 described in Embodiment 4. That is, as shown in FIG. 17, the wireless device 453 included in the terminal 1050 transmits, for example, the preamble 1201, and then transmits the control information symbol 1202 and the information symbol 1203.

[0239] The preamble 1201 is a symbol used by the base station (or AP) 470 that receives the modulation 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, and the like.

[0240] The control information symbol 1202 is a symbol including data such as, for example, the method of the error correction coding method, information regarding the modulation method, information regarding the frame configuration, and information regarding the transmission method used to generate the modulation signal. The base station 470 performs demodulation of the modulation signal and the like based on the information included in the control information symbol 1202.

[0241] The information symbol 1203 is a symbol for the radio device 453 of the terminal 1050 to transmit data.

[0242] Note that the radio device 453 of the terminal 1050 shown in FIG. 19 may transmit a frame including symbols other than the symbols described in FIG. 17. For example, the radio device 453 may transmit a frame including a pilot symbol (reference symbol) in the middle of the information symbol 1203. Also, the frame configuration is not limited to the configuration of FIG. 17, including the order in which symbols are transmitted. Also, in FIG. 17, there may be a plurality of symbols in the frequency axis direction. That is, in FIG. 17, symbols may exist on a plurality of frequencies (a plurality of carriers).

[0243] The frame configuration of the modulation signal transmitted by the base station 470 in the present embodiment is the same as the frame configuration of FIG. 12 described in Embodiment 3. That is, as shown in FIG. 12, the base station 470 transmits, for example, a preamble 701, and then transmits a control information symbol 702 and an information symbol 703.

[0244] The preamble 701 is a symbol for the radio device 453 of the terminal 1050 that receives the modulation signal transmitted by the base station 470 to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, etc.

[0245] The control information symbol 702 is a symbol including data such as, for example, the method of error correction coding, information on the modulation method, information on the frame configuration, and information on the transmission method used to generate the modulation signal. The radio device 453 of the terminal 1050 in FIG. 19 performs demodulation of the modulation signal based on the information of the control information symbol 702.

[0246] The information symbol 703 is a symbol for the base station 470 in FIG. 19 to transmit data.

[0247] Note that the base station 470 shown in FIG. 19 may transmit a frame including symbols other than the symbols described in FIG. 12. For example, the base station 470 may transmit a frame including a pilot symbol (reference symbol) in the middle of the information symbol 703. Also, the frame configuration is not limited to the configuration of FIG. 12, including the order in which symbols are transmitted. Also, in FIG. 12, there may be a plurality of symbols in the frequency axis direction. That is, in FIG. 12, symbols may exist on a plurality of frequencies (a plurality of carriers).

[0248] Also, for example, a modulation signal having the frame configuration of FIG. 20 transmitted by the third device 1400A may be transmitted at regular timing, for example, repeatedly. Thereby, a plurality of terminals 1050 can perform the operations as described above. Similarly, a modulation signal having the frame configuration of FIG. 21 transmitted by the fourth device 1400B may be transmitted at regular timing, for example, repeatedly. Thereby, a plurality of terminals 1050 can perform the operations as described above.

[0249] FIG. 22 is a flowchart showing a first example of the processes performed by the "third device 1400A", "fourth device 1400B", "terminal 1050", and "base station 470" shown in FIG. 19. Note that, in FIG. 22, those that operate in the same manner as in FIG. 18 are given the same numbers.

[0250] First, the third device 1400A transmits a modulation signal having the frame configuration shown in FIG. 20 (ST1701).

[0251] Then, the terminal 1050 receives the modulation signal transmitted by the third device 1400A and acquires the SSID of the base station 470 to which the terminal 1050 accesses (ST1702).

[0252] Next, the fourth device 1400B transmits a modulation signal having the frame configuration shown in FIG. 21 (ST1703).

[0253] Then, the terminal 1050 receives the modulation signal transmitted by the fourth device 1400B and obtains an encryption key used for communication with the base station 470 accessed by the terminal 1050 (ST1704).

[0254] Then, the terminal 1050 performs a radio connection with the base station 470 (ST1304). When the terminal 1050 receives a response from the base station 470, the radio connection with the base station 470 is completed (ST1305).

[0255] Then, the terminal 1050 transmits connection destination information to the base station 470 using radio waves (ST1306).

[0256] The base station 470 obtains information to be transmitted to the terminal 1050 from the network (ST1307).

[0257] Then, the base station 470 transmits the obtained information to the terminal 1050 using radio waves, and the terminal 1050 obtains the information (ST1308). The terminal 1050 obtains necessary information from the network via the base station 470 when necessary, for example.

[0258] FIG. 23 is a flowchart showing a second example of the processes performed by the "third device 1400A", "fourth device 1400B", "terminal 1050", and "base station 470" shown in FIG. 19. In FIG. 23, components that operate in the same manner as those in FIG. 18 are given the same reference numerals.

[0259] First, the fourth device 1400B transmits a modulation signal having the frame configuration shown in FIG. 21 (ST1801).

[0260] Then, the terminal 1050 receives the modulation signal transmitted by the fourth device 1400B and obtains an encryption key used for communication with the base station 470 accessed by the terminal 1050 (ST1802).

[0261] Next, the third device 1400A transmits a modulation signal having the frame configuration shown in FIG. 20 (ST1803).

[0262] Then, the terminal 1050 receives the modulated signal transmitted by the third device 1400A and obtains the SSID of the base station 470 to which the terminal 1050 accesses (ST1804).

[0263] Then, the terminal 1050 performs a radio connection with the base station 470 (ST1304). When the terminal 1050 receives a response from the base station 470, the radio connection with the base station 470 is completed (ST1305).

[0264] Then, the terminal 1050 transmits the connection destination information to the base station 470 using radio waves (ST1306).

[0265] The base station 470 obtains information to be transmitted to the terminal 1050 from the network (ST1307).

[0266] Then, the base station 470 transmits the obtained information to the terminal 1050 using radio waves, and the terminal 1050 obtains the information (ST1308). The terminal 1050 obtains necessary information from the network via the base station 470 when necessary, for example.

[0267] As described above, based on the SSID transmitted from the third device 1400A and the information on the encryption key transmitted from the fourth device 1400B, the terminal 1050 connects to the base station 470 and obtains information. That is, since the device for the terminal 1050 to obtain the SSID information is different from the device for obtaining the encryption key information, information can be safely obtained via the base station 470 with guaranteed security. This is because when the terminal 1050 obtains information from the modulated signal of visible light, it is easy for the user to determine whether the information source is secure because it is visible light. On the other hand, for example, when the SSID is obtained from the modulated signal of the radio wave transmitted by the wireless LAN, it is difficult for the user to identify the device that transmitted the radio wave. Therefore, in terms of ensuring information security, visible light communication is more suitable for obtaining the SSID compared to wireless LAN communication.

[0268] In addition, in this embodiment, the case where the fourth device 1400B transmits the information on the encryption key has been described. However, for example, when the base station 470 is not performing encrypted communication using the encryption key, the information on the encryption key may not be transmitted by the fourth device 1400B, and only the information on the SSID may be transmitted by the third device 1400A. In this case, in the above-described configuration, it can be similarly implemented by simply deleting the configuration related to the encryption key.

[0269] Also, as in this embodiment, by separating the device (the third device 1400A) that transmits the information on the SSID and the device (the fourth device 1400B) that transmits the information on the encryption key, the terminal 1050 can achieve more secure communication with the base station 470.

[0270] For example, consider a space as shown in FIG. 24. In FIG. 24, there are Area #1 and Area #2, and there are an entrance / exit and a wall between Area #1 and Area #2. That is, in the space of FIG. 24, it is assumed that movement from Area #1 to Area #2 and movement from Area #2 to Area #1 can only be done through the entrance / exit.

[0271] It is assumed that the base station 470, the third device 1400A, and the fourth device 1400B are respectively installed in Area #1 of FIG. 24. On the other hand, it is assumed that only the third device 1400A is installed in Area #2. Also, in FIG. 24, it is assumed that the radio waves transmitted by the base station 470 can be received in both Area #1 and Area #2.

[0272] At this time, the terminal 1050 present in Area #1 where the fourth device 1400B is installed can obtain the encryption key of the base station 470 from the fourth device 1400B and can communicate with the base station 470. Also, even when the terminal 1050 that has connected to the base station 470 in Area #1 moves to Area #2, it can communicate with the base station 470 using the encryption key obtained from the fourth device 1400B in Area #1. Further, even when the terminal 1050 that has connected to the base station 470 in Area #1 moves to an area other than Area #1 and Area #2 and then returns to either Area #1 or Area #2, it can communicate with the base station 470 using the encryption key obtained from the fourth device 1400B in Area #1.

[0273] On the other hand, a terminal 1050 that cannot enter Area #1 cannot obtain the encryption key from the fourth device 1400B. In this case, the terminal 1050 only knows the SSID of the base station (or AP) 470. Therefore, for example, the terminal 1050 may be enabled to receive communication with the base station 470 by a service that can be enjoyed by only knowing the SSID of the base station 470. The service that can be enjoyed by only knowing the SSID of the base station 470 can be made more limited than the service that can be enjoyed when both the SSID and the encryption key are known.

[0274] Therefore, only the terminal 1050 that has been able to enter Area #1 can communicate with the base station 470. Thereby, the security of communication can be ensured. Also, it becomes possible to construct a system that can provide different services for each area.

[0275] Note that by changing the encryption key for the terminal 1050 to communicate with the base station 470 (for example, at regular time intervals), the terminal 1050 that holds the encryption key before the change can no longer communicate with the base station 470. By performing such an operation, it becomes possible to perform more secure communication.

[0276] In addition, the configurations of the third device and 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.

[0277] Also, in FIG. 19, the case where one base station 470 is arranged is described, but there may be a plurality of base stations (or APs) to which the terminal 1050 can access (safely). At this time, the symbol regarding the SSID transmitted by the third device 1400A in FIG. 19 may include information on the SSIDs of these plurality of base stations 470. Also, the symbol regarding the encryption key transmitted by the fourth device 1400B in FIG. 19 may include information on the encryption keys used to connect to each of these plurality of base stations. In this case, on the display unit 157 of the terminal 1050 in FIG. 19, a list of the SSIDs of the plurality of base stations and / or a list of the plurality of access destinations are displayed as the access destination display (the aforementioned "first display"). Then, the terminal 1050 in FIG. 19 may select one or more base stations to actually perform a wireless connection based on the information on the SSIDs of the plurality of base stations and the information on the encryption keys (that is, it may be connected to a plurality of base stations simultaneously).

[0278] For example, assume that three base stations 470 are arranged. Here, the three base stations 470 are respectively called base station #A, base station #B, and base station #C. 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".

[0279] In this case, the symbol 600-1 regarding the SSID in the frame configuration of FIG. 20 of the modulation signal transmitted by the third device 1400A contains 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". Also, the symbol 1101 regarding the encryption key in the frame configuration of FIG. 21 of the modulation signal transmitted by the fourth device 1400B contains 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".

[0280] Then, the terminal 1050 in FIG. 19 receives the symbol 600-1 regarding the SSID and obtains the information of "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, the terminal 1050 receives the symbol 1101 regarding the encryption key and obtains the information regarding "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, the terminal 1050 selects and connects to a base station for wireless connection (for example, by radio waves).

[0281] Also, as in this embodiment, by using a light source such as an LED as an example to set the base station 470 accessed by the terminal 1050, a special setting mode for performing procedures for connecting the wireless communication between the terminal 1050 and the base station 470 is not required for the modulation signal for wireless transmission transmitted by the terminal 1050. Also, a special setting mode for performing procedures for connecting the wireless communication between the terminal 1050 and the base station 470 is not required for the modulation signal transmitted by the base station 470. Therefore, in this embodiment, the data transmission efficiency of wireless communication can be improved.

[0282] Also, the encryption key may be an encryption key for the SSID of the wireless LAN as described above, or may be an encryption key for restricting the connection form, service form, network connection range, etc. That is, an encryption key may be introduced for some kind of restriction.

[0283] (Embodiment 6) FIG. 25 is a diagram showing an example of the configuration of the communication system in the present embodiment.

[0284] The communication system in FIG. 25 includes, for example, a base station 2000 and a terminal 1050. The base station 2000 includes a transmission device 2001 and a wireless device 2002. In FIG. 25, those that operate in the same manner as in FIGS. 6 and 15 are given the same numbers. Also, the communication between the wireless device 2002 and the wireless device 453 in FIG. 25 uses, for example, radio waves.

[0285] The transmission device 2001 of the base station (or AP) 2000 in FIG. 25 includes, for example, a visible light source such as an LED, lighting, a light source, a light (hereinafter referred to as the light source 104). First, the operation of the transmission device 2001 (that is, the part related to the "visible light source such as an LED, lighting, light source, light") will be described.

[0286] In the transmission device 2001, the transmission unit 102 takes the information 1001-1 regarding the SSID, the information 1001-2 regarding the encryption key, and the data 1002 as inputs, and based on these input signals, generates a (light) modulation signal 103 and outputs the modulation signal 103. Then, the modulation signal 103 is transmitted from the light source 104, for example.

[0287] Next, the information 1001-1 regarding the SSID and the information 1001-2 regarding the encryption key will be described.

[0288] First, the information 1001-1 regarding the SSID will be described.

[0289] The information 1001-1 regarding the SSID is information indicating the SSID of the wireless device 2002 that uses radio waves of the base station 2000 in FIG. 25. That is, the transmission device 2001 can provide access to the wireless device 2002, which is a secure wireless access destination for the terminal 1050. As a result, the terminal 1050 in FIG. 25 can safely obtain information from the wireless device 2002.

[0290] On the other hand, the transmission device 2001 can limit the terminal accessing the wireless device 2002 to a terminal located in a space where the optical signal transmitted (irradiated) by the transmission device 2001 can be received.

[0291] In addition, when the 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. Also, the terminal 1050 may separately perform a process of determining whether the notified SSID is secure. For example, the transmission device 2001 includes a predetermined identifier in the optical signal and transmits it, and the terminal 1050 may determine whether the notified SSID is the SSID of a secure base station based on the received identifier.

[0292] Note that in FIG. 25, only the base station 2000 is shown. However, for example, when there are base stations (or APs) other than the base station 2000, the terminal 1050 uses the SSID and encryption key obtained from the transmission device 2001 to access the wireless device 2002 of the base station 2000 and obtain information.

[0293] Next, the information 1001-2 regarding the encryption key will be described.

[0294] The information 1001-2 regarding the encryption key is information regarding the encryption key necessary for the terminal 1050 to communicate with the wireless device 2002. By obtaining the information 1001-2 regarding the encryption key from the transmission device 2001, the terminal 1050 can perform encrypted communication with the wireless device 2002.

[0295] The above has described the information 1001-1 regarding the SSID and the information 1001-2 regarding the encryption key.

[0296] The terminal 1050 in FIG. 25 receives the modulated signal transmitted by the transmission device 2001. Note that, in the terminal 1050 in FIG. 25, the components that operate in the same manner as the terminal 150 in FIG. 6 and the terminal 1050 in FIG. 15 are given the same numbers.

[0297] 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 the light including the modulated signal transmitted from the transmission device 2001 and outputs a received signal 152.

[0298] Then, the receiving unit 153 takes the received signal 152 received by the light receiving unit 151 as an input, performs processes such as demodulation and error correction decoding on the modulated signal included in the received signal 152, and outputs received data 154.

[0299] The data analysis unit 155 takes the received data 154 as an input, and outputs, for example, the information 1051 of the SSID of the wireless device 2002 of the base station 2000 to be connected to and the information 1052 of the encryption key for communicating with the wireless device 2002 of the base station 2000 to be connected to from the received data. For example, in a wireless LAN (Local Area Network), as encryption methods, there are 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). Note that the encryption method is not limited to this.

[0300] The display unit 157 takes the SSID information 1051 and the encryption key information 1052 as inputs, and displays, for example, the SSID of the communication partner accessed by the wireless device 453 included in the terminal 1050 and the encryption key (this display is referred to as the "first display" in the present embodiment).

[0301] For example, after the first display, the wireless device 453 of the terminal 1050 uses the SSID information 1051 and the encryption key information 1052 as inputs to establish a connection with the wireless device 2002 of the base station 2000 (for example, assume the connection uses radio waves). At this time, when the wireless device 2002 of the base station 2000 communicates with the wireless device 453 of the terminal 1050, it transmits a modulation signal using, for example, radio waves.

[0302] After that, the wireless device 453 uses the data 1053 and the control signal 1054 as inputs, modulates the data 1053 according to the control indicated by the control signal 1054, and transmits the modulation signal by radio waves.

[0303] Then, for example, the wireless device 2002 of the base station 2000 transmits data (471) to the network and receives data (472) from the network. After that, for example, the wireless device 2002 of the base station 2000 transmits a modulation signal to the terminal 1050 by radio waves.

[0304] The wireless device 453 of the terminal 1050 performs processes such as demodulation and error correction decoding on the modulation signal received by radio waves, and obtains the received data 1056. The display unit 157 performs a display based on the received data 1056.

[0305] The frame configuration of the modulation signal transmitted by the transmission device 2001 of the base station 2000 in the present embodiment is the same as the frame configuration of FIG. 16 described in Embodiment 4. That is, in FIG. 16, the symbol 600-1 related to the SSID is a symbol for transmitting the information 1001-1 related to the SSID in FIG. 25, and the symbol 1101 related to the encryption key is a symbol for transmitting the information 1001-2 related to the encryption key in FIG. 25. The data symbol 1102 is a symbol for transmitting the data 1002 in FIG. 25.

[0306] As shown in FIG. 16, the transmission device 2001 of the base station 2000 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. Note that the transmission device 2001 of the base station 2000 may transmit a frame including symbols other than the symbols described in FIG. 16. Also, the frame configuration is not limited to the configuration of FIG. 16, including the order in which the symbols are transmitted.

[0307] The frame configuration of the modulation signal transmitted by the wireless device 453 included in the terminal 1050 in the present embodiment is the same as the frame configuration of FIG. 17 described in Embodiment 4. That is, as shown in FIG. 17, the wireless device 453 included in the terminal 1050 of FIG. 25 transmits, for example, a preamble 1201, and then transmits a control information symbol 1202 and an information symbol 1203.

[0308] At this time, the preamble 1201 is a symbol used by the wireless device 2002 of the base station 2000 that receives the modulation signal transmitted by the wireless device 453 to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, and the like.

[0309] The control information symbol 1202 is a symbol including data such as, for example, the method of the error correction coding method used by the terminal 1050 to generate the modulation signal, information related to the modulation method, information related to the frame configuration, and information related to the transmission method. The wireless device 2002 of the base station 2000 performs demodulation of the modulation signal and the like based on the information included in the control information symbol 1202.

[0310] The information symbol 1203 is a symbol for the wireless device 453 of the terminal 1050 to transmit data.

[0311] Note that the wireless device 453 of the terminal 1050 may transmit a frame including symbols other than those described in FIG. 17. For example, the wireless device 453 may transmit a frame including a pilot symbol (reference symbol) in the middle of the information symbol 1203. Further, the frame configuration is not limited to the configuration of FIG. 17, including the order in which the symbols are transmitted. Also, in FIG. 17, there may be a plurality of symbols in the frequency axis direction. That is, in FIG. 17, symbols may exist at a plurality of frequencies (a plurality of carriers).

[0312] The frame configuration of the modulation signal transmitted by the wireless device 2002 in the present embodiment is the same as the frame configuration of FIG. 12 described in Embodiment 3. That is, as shown in FIG. 12, the wireless device 2002 transmits, for example, a preamble 701, and then transmits a control information symbol 702 and an information symbol 703.

[0313] The preamble 701 is a symbol for the wireless device 453 of the terminal 1050 that receives the modulation signal transmitted by the wireless device 2002 to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, and the like.

[0314] The control information symbol 702 is a symbol including data such as, for example, the method of error correction coding, information on the modulation method, information on the frame configuration, and information on the transmission method used to generate the modulation signal. The wireless device 453 of the terminal 1050 performs demodulation of the modulation signal based on the information of the control information symbol 702.

[0315] The information symbol 703 is a symbol for the wireless device 2002 to transmit data.

[0316] Note that the radio device 2002 of the base station 2000 shown in FIG. 25 may transmit a frame including symbols other than the symbols described in FIG. 12. For example, the radio device 2002 may transmit a frame including a pilot symbol (reference symbol) in the middle of the information symbol 703. Further, the frame configuration is not limited to the configuration of FIG. 12, including the order in which the symbols are transmitted. Also, in FIG. 12, there may be a plurality of symbols in the frequency axis direction. That is, in FIG. 12, symbols may exist on a plurality of frequencies (a plurality of carriers).

[0317] Also, for example, the modulation signal having the frame configuration of FIG. 16 transmitted by the transmitting device 2001 may be transmitted in a regular timing, for example, repeatedly. Thereby, a plurality of terminals 1050 can perform the operations as described above.

[0318] FIG. 26 is a flowchart showing an example of the processing performed by the "transmitting device 2001 of the base station 2000", "terminal 1050", and "radio device 2002 of the base station 2000" shown in FIG. 25.

[0319] First, the transmitting device 2001 transmits a modulation signal having the frame configuration of FIG. 16 (ST1301).

[0320] Then, the terminal 1050 receives the modulation signal transmitted by the transmitting device 2001 and acquires the SSID of the base station 2000 (radio device 2002) to which the terminal 1050 accesses (ST1302).

[0321] In addition, the terminal 1050 acquires an encryption key used for communication with the base station 2000 (radio device 2002) to which the terminal 1050 accesses (ST1303).

[0322] Then, the terminal 1050 performs a radio connection with the radio device 2002 of the base station 2000 (ST1304). When the terminal 1050 receives a response from the radio device 2002 of the base station 2000, the connection between the terminal 1050 and the radio device 2002 of the base station 2000 is completed (ST1305).

[0323] Then, the terminal 1050 transmits the connection destination information to the wireless device 2002 of the base station 2000 using radio waves (ST1306).

[0324] The wireless device 2002 of the base station 2000 obtains information to be transmitted to the terminal 1050 from the network (ST1307).

[0325] Then, the wireless device 2002 of the base station 2000 transmits the obtained information to the terminal 1050 using radio waves, and the terminal 1050 obtains the information (ST1308). The terminal 1050 obtains necessary information from the network via the wireless device 2002 of the base station 2000 when necessary, for example.

[0326] As described above, based on the SSID information and the encryption key information transmitted from the transmission device 2001 of the base station 2000, the terminal 1050 connects to the wireless device 2002 of the base station 2000 and obtains information, thereby safely obtaining information via the base station 2000 with guaranteed security. This is because when the terminal 1050 obtains information from the modulation signal of visible light, since it is visible light, it is easy for the user to determine whether the information source is safe. On the other hand, for example, when the SSID is obtained from the modulation signal of the radio wave transmitted by the wireless LAN, it is difficult for the user to identify the device that transmitted the radio wave. Therefore, in terms of ensuring information security, visible light communication is more suitable for obtaining the SSID compared to wireless LAN communication.

[0327] In addition, in this embodiment, the case where the transmission device 2001 transmits the encryption key information has been described. However, for example, when the wireless device 2002 of the base station 2000 is not performing encrypted communication using an encryption key, the transmission device 2001 may transmit only the information regarding the SSID without transmitting the encryption key information. In this case, it can be similarly implemented by simply deleting the configuration related to the encryption key in the configuration of the transmission device 2001.

[0328] Further, as shown in FIG. 25, the wireless device 2002 of the base station 2000 may be configured to be able to rewrite the SSID and the encryption key. For example, in FIG. 25, information 1001-1 regarding the SSID and information 1001-2 regarding the encryption key are input to the wireless device 2002. The wireless device 2002 of the base station 2000 rewrites the SSID and the encryption key based on the input information 1001-1 regarding the SSID and information 1001-2 regarding the encryption key. In this way, the security of the communication between the terminal 1050 and the wireless device 2002 of the base station 2000 is further ensured. Note that in FIG. 25, the wireless device 2002 of the base station 2000 has the function of rewriting the SSID and the encryption key, but a configuration without the function of rewriting both or either one of the SSID and the encryption key may also be used.

[0329] Further, the configuration of the transmission device is not limited to the configuration of the transmission device 2001 shown in FIG. 25, the configuration of the terminal is not limited to the configuration of the terminal 1050 shown in FIG. 25, and the connection destination and configuration of the wireless device are not limited to the connection destination and configuration of the wireless device 2002 shown in FIG. 25.

[0330] Also, in FIG. 25, the case where one base station 2000 is arranged is described, but there may be a plurality of wireless devices 2002 of the base station (or AP) 2000 that the terminal 1050 can access (safely). Note that these plurality of wireless devices 2002 of the base station 2000 and the terminal 1050 will transmit and receive modulation signals using radio waves. At this time, the symbol regarding the SSID transmitted by the transmission device 2001 in FIG. 25 may include information on the SSIDs of these plurality of wireless devices 2002 of the base station 2000. Further, the symbol regarding the encryption key transmitted by the transmission device 2001 in FIG. 25 may include information on the encryption keys used for connecting to each of these plurality of wireless devices 2002 of the base station 2000. Then, the terminal 1050 in FIG. 25 may select (or may connect to the wireless devices of a plurality of base stations) the wireless device 2002 of the base station 2000 to perform wireless connection (for example, by radio waves) based on the SSID information and encryption key information of the plurality of wireless devices 2002 of the base station 2000.

[0331] 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 respectively referred to as wireless device #A, wireless device #B, and wireless device #C. Also, let the SSID of wireless device #A be "abcdef", the SSID of wireless device #B be "ghijk", and the SSID of wireless device #C be "pqrstu". Further, let the encryption key for connecting to wireless device #A be "123", the encryption key for connecting to wireless device #B be "456", and the encryption key for connecting to wireless device #C be "789".

[0332] In this case, the symbol 600-1 regarding the SSID in the frame configuration of FIG. 16 of the modulation signal transmitted by the transmission device 2001 includes the information of "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, the symbol 1101 regarding the encryption key in the frame configuration of FIG. 16 includes the information of "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] Then, the terminal 1050 in FIG. 25 receives the symbol 600-1 regarding the SSID and obtains the information of "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, the terminal 1050 receives the symbol 1101 regarding the encryption key and obtains the information regarding "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"". Then, based on this information, the terminal 1050 selects and connects to a base station for wireless connection (for example, by radio waves).

[0334] Also, by setting the wireless device 2002 of the base station 2000 accessed by the terminal 1050 using a light source such as an LED as in this embodiment, a special setting mode for performing procedures for connecting the wireless communication between the terminal 1050 and the base station 2000 is not required for the modulation signal for wireless transmission by the terminal 1050. Also, a special setting mode for performing procedures for connecting the wireless communication between the terminal 1050 and the base station 2000 is not required for the modulation signal transmitted by the base station 2000. Therefore, in this embodiment, the data transmission efficiency of wireless communication can be improved.

[0335] Also, the encryption key may be an encryption key for the SSID of the wireless LAN as described above, or may be an encryption key for restricting the connection form, service form, network connection range, etc. That is, an encryption key may be introduced for some kind of restriction.

[0336] (Embodiment 7) FIG. 27 is a diagram showing an example of the configuration of the communication system in this embodiment.

[0337] The communication system in FIG. 27 includes a device 1000, a terminal 1050, a base station (or AP) 470-1 (base station #1) that communicates with the terminal 1050, a base station (or AP) 470-2 (base station #2), and a base station (or AP) 470-3 (base station #3). In FIG. 27, those that operate in the same manner as FIGS. 6, 9, and 15 are given the same numbers.

[0338] The device 1000 includes, for example, visible light such as an LED, lighting, a light source, a light (light source 104). Hereinafter, the device 1000 will be referred to as the "fifth device" in this embodiment. Also, 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) use, for example, radio waves.

[0339] In the fifth device 1000 of FIG. 27, the transmission unit 102 takes information 1001-1 regarding the SSID, information 1001-2 regarding the encryption key, and data 1002 as inputs, generates a (light) modulation signal 103 based on these input signals, and outputs the modulation signal 103. Then, the modulation signal 103 is transmitted, for example, from the light source 104.

[0340] Next, the information 1001-1 regarding the SSID and the information 1001-2 regarding the encryption key will be described.

[0341] First, the information 1001-1 regarding the SSID will be described.

[0342] The information 1001-1 regarding the SSID includes, for example, information indicating the SSID of the base station 470-1 (base station #1) in FIG. 27, information indicating the SSID of the base station 470-2 (base station #2), and information indicating the SSID of the base station 470-3 (base station #3). Note that, as an example, the base stations 470-1, 470-2, and 470-3 transmit modulation signals by radio waves and receive radio wave modulation signals. That is, the fifth device 1000 can provide access to the base stations 470-1, 470-2, and 470-3, which are secure access destinations for the terminal 1050. Thereby, the terminal 1050 in FIG. 27 can safely obtain information from the base stations 470-1, 470-2, and 470-3.

[0343] On the other hand, the fifth device 1000 can limit the terminals accessing the base stations 470-1, 470-2, and 470-3 to terminals located in a space where the light signal transmitted (irradiated) by the fifth device 1000 can be received.

[0344] In addition, when the 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. Further, the terminal 1050 may separately perform a process of determining whether the notified SSID is secure. For example, the fifth device 1000 may include a predetermined identifier in the optical signal, and the terminal 1050 may determine whether the notified SSID is the SSID of a secure base station based on the received identifier.

[0345] Note that in FIG. 27, base stations 470-1, 470-2, and 470-3 are shown. However, for example, base stations (or APs) other than base stations 470-1, 470-2, and 470-3 may exist.

[0346] Next, information 1001-2 regarding the encryption key will be described.

[0347] Information 1001-2 regarding the encryption key is information regarding the encryption key necessary for the terminal 1050 to communicate with base stations 470-1, 470-2, and 470-3. By obtaining information 1001-2 regarding the encryption key from the fifth device 1000, the terminal 1050 can perform encrypted communication "between the terminal 1050 and the base station 470-1", "between the terminal 1050 and the base station 470-2", and "between the terminal 1050 and the base station 470-3".

[0348] Above, information 1001-1 regarding the SSID and information 1001-2 regarding the encryption key have been described.

[0349] The terminal 1050 in FIG. 27 receives the modulation signal transmitted by the fifth device 1000. Note that, in the terminal 1050 in FIG. 27, components that operate in the same manner as the terminal 150 in FIG. 6 and the terminal 450 in FIG. 9 are given the same numbers.

[0350] 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 the modulation signal transmitted from the fifth device 1000 and outputs a received signal 152.

[0351] Then, the receiving unit 153 takes the received signal 152 received by the light receiving unit 151 as an input, performs processes such as demodulation and error correction decoding on the modulation signal included in the received signal 152, and outputs received data 154.

[0352] The data analysis unit 155 takes the received data 154 as an input, and outputs, for example, information 1051 on the SSIDs of the base stations 470-1, 470-2, and 470-3 that are the connection destinations, and information 1052 on the encryption keys for communicating with the base stations 470-1, 470-2, and 470-3 from the received data 154. For example, in a wireless LAN (Local Area Network), as encryption methods, there are 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). Note that the encryption method is not limited to this.

[0353] The display unit 157 takes the SSID information 1051 and the encryption key information 1052 as inputs, and displays, for example, the SSID of the communication partner accessed by the wireless device 453 included in the terminal 1050 and the encryption key (this display is referred to as the "first display" in the present embodiment).

[0354] For example, after the first display, the wireless device 453 takes the SSID information 1051 and the encryption key information 1052 as inputs and establishes a connection with any one of the base stations 470-1, 470-2, and 470-3 (for example, assume the connection uses radio waves). At this time, when the connected base station 470 also communicates with the wireless device 453 included in the terminal 1050, it transmits a modulation signal using, for example, radio waves.

[0355] Subsequently, the wireless device 453 takes the data 1053 and the control signal 1054 as inputs, modulates the data 1053 according to the control indicated by the control signal 1054, and transmits the modulated signal as a radio wave.

[0356] Then, for example, the connected base station 470 transmits data (any one of 471-1, 471-2, 471-3) to the network and receives data from the network (any one of 472-1, 472-2, 472-3). Subsequently, for example, the connected base station 470 transmits the modulated signal to the terminal 1050 by radio waves.

[0357] The wireless device 453 included in the terminal 1050 performs processes such as demodulation and error correction decoding on the modulated signal received by radio waves, and obtains the received data 1056. The display unit 157 performs display based on the received data 1056.

[0358] As the modulated signal transmitted by the fifth device 1000, in the case of FIG. 27, there are three types of frame configurations. FIG. 28 is a frame 2300-1 (frame #1) which is one of the three types of frame configurations, FIG. 29 is a frame 2300-2 (frame configuration #2) which is one of the three types of frame configurations, and FIG. 30 is a frame 2300-3 (frame configuration #3) which is one of the three types of frame configurations.

[0359] FIG. 28 shows an example of the configuration of the frame 2300-1 (frame #1) of the modulated signal transmitted by the fifth device 1000. In FIG. 28, the horizontal axis represents time. Also, in FIG. 28, the same symbols as in FIGS. 2 and 16 are given the same numbers, and the description is omitted. The frame 2300-1 (frame #1) in FIG. 28 is a frame for transmitting the SSID information of the base station 470-1 (base station #1) in FIG. 27 and the information of the encryption key (the encryption key for accessing the base station 470-1) of the base station 470-1.

[0360] The symbol 2301-1 related to the SSID is a symbol for transmitting the information 1001-1 related to the SSID in FIG. 27. Also, the symbol 2301-1 related to the SSID is a symbol for the fifth device 1000 in FIG. 27 to transmit the SSID of the base station 470-1 (base station #1).

[0361] The symbol 2302-1 related to the encryption key is a symbol for transmitting the information 1001-2 related to the encryption key in FIG. 27. Also, the symbol 2302-1 related to the encryption key is a symbol for the fifth device 1000 in FIG. 27 to transmit the encryption key of the base station 470-1 (base station #1) (the encryption key for accessing the base station 470-1).

[0362] The fifth device 1000 transmits the preamble 201, the control information symbol 202, the symbol 2301-1 related to the SSID, the symbol 2302-1 related to the encryption key, and the data symbol 1102. Note that the fifth device 1000 may transmit a frame 2300-1 (frame #1) including symbols other than those described in FIG. 28. Also, the configuration of the frame 2300-1 (frame #1), including the order of transmitting the symbols, is not limited to the configuration of FIG. 28.

[0363] FIG. 29 shows an example of the configuration of the frame 2300-2 (frame #2) of the modulation signal transmitted by the fifth device 1000. In FIG. 29, the horizontal axis represents time. Also, in FIG. 29, the same symbols as those in FIGS. 2 and 16 are given the same numbers and the description is omitted. The frame 2300-2 (frame #2) in FIG. 29 is a frame for transmitting the information of the SSID of the base station 470-2 (base station #2) in FIG. 27 and the information of the encryption key of the base station 470-2 (base station #2) (the encryption key for accessing the base station 470-2).

[0364] The symbol 2301-2 related to the SSID is a symbol for transmitting the information 1001-1 related to the SSID in FIG. 27. Also, the symbol 2301-2 related to the SSID is a symbol for the fifth device 1000 in FIG. 27 to transmit the SSID of the base station 470-2 (base station #2).

[0365] The symbol 2302-2 related to the encryption key is a symbol for transmitting the information 1001-2 related to the encryption key in FIG. 27. Also, the symbol 2302-2 related to the encryption key is a symbol for the fifth device 1000 in FIG. 27 to transmit the encryption key (the encryption key for accessing the base station 470-2) of the base station 470-2.

[0366] The fifth device 1000 transmits the preamble 201, the control information symbol 202, the symbol 2301-2 related to the SSID, the symbol 2302-2 related to the encryption key, and the data symbol 1102. Note that the fifth device 1000 may transmit a frame 2300-2 (frame #2) including symbols other than the symbols described in FIG. 29. Also, the configuration of the frame 2300-2 (frame #2), including the order in which the symbols are transmitted, is not limited to the configuration of FIG. 29.

[0367] FIG. 30 shows an example of the configuration of the frame 2300-3 (frame #3) of the modulation signal transmitted by the fifth device 1000. In FIG. 30, the horizontal axis represents time. Also, in FIG. 30, the same symbols as those in FIGS. 2 and 16 are given the same numbers and the description is omitted. The frame 2300-3 (frame #3) in FIG. 30 is a frame for transmitting the information of the SSID of the base station 470-3 (base station #3) in FIG. 27 and the information of the encryption key (the encryption key for accessing the base station 470-3) of the base station 470-3.

[0368] The symbol 2301-3 regarding the SSID is a symbol for transmitting the information 1001-1 regarding the SSID in FIG. 27. Also, the symbol 2301-3 regarding the SSID is a symbol for the fifth device 1000 in FIG. 27 to transmit the SSID of the base station 470-3 (base station #3).

[0369] The symbol 2302-3 regarding the encryption key is a symbol for transmitting the information 1001-2 regarding the encryption key in FIG. 27. Also, the symbol 2302-3 regarding the encryption key is a symbol for the fifth device 1000 to transmit the encryption key of the base station 470-3 (the encryption key for accessing the base station 470-3).

[0370] The fifth device 1000 transmits the preamble 201, the control information symbol 202, the symbol 2301-3 regarding the SSID, the symbol 2302-3 regarding the encryption key, and the data symbol 1102. Note that the fifth device 1000 may transmit a frame 2300-3 (frame #3) including symbols other than those described in FIG. 30. Also, the configuration of the frame 2300-3 (frame #3), including the order in which the symbols are transmitted, is not limited to the configuration in FIG. 30.

[0371] FIG. 31 shows an example of the transmission method when the fifth device 1000 transmits "the frame 2300-1 (frame #1) in FIG. 28", "the frame 2300-2 (frame #2) in FIG. 29", and "the frame 2300-3 (frame #3) in FIG. 30". In FIG. 31, the horizontal axis represents time.

[0372] In FIG. 31, in the "frame #1 group transmission" 2601-1, 2601-2, one or more of the frames 2300-1 (frame #1) in FIG. 28 are transmitted. Also, in the "frame #2 group transmission" 2602-1, 2602-2, one or more of the frames 2300-2 (frame #2) in FIG. 29 are transmitted. Also, in the "frame #3 group transmission" 2603-1, 2603-2, one or more of the frames 2300-3 (frame #3) in FIG. 30 are transmitted.

[0373] A detailed explanation will be given below.

[0374] First, regarding the fact that one or more frames 2300-1 (frame #1) of FIG. 28 are transmitted in the "frame #1 group transmission" 2601-1 and 2601-2, an explanation will be given.

[0375] For example, when an image sensor such as a CMOS or an organic CMOS is used in the light receiving unit 151, there is a possibility of processing the received signal in units of frames in a moving image or a still image. For example, when it is described as "4K 30p" in a moving image, it means that the number of pixels in one frame is 3840×2160 and the number of frames per second is 30.

[0376] Therefore, when the fifth device 1000 transmits a modulated signal configured such that "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" exist within one frame, it becomes difficult for the terminal 1050 in FIG. 27 to select the base station 470 to access from the plurality of base stations 470-1, 470-2, and 470-3.

[0377] Therefore, in the present embodiment, a frame configuration as shown in FIG. 31 is proposed.

[0378] <First - 1 method> As the first - 1 method, by including a plurality of frames 2300-1 (frame #1) of FIG. 28 in each of the "frame #1 group transmission" 2601-1 and 2601-2, the time intervals occupied by each of the "frame #1 group transmission" 2601-1 and 2601-2 are made longer than the frames in a moving image or a still image.

[0379] By doing so, the terminal 1050 can prevent receiving modulation signals including different SSIDs and encryption keys, such as "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", within one frame of a video or a still image from the fifth device 1000. Therefore, the terminal 1050 in FIG. 27 can easily select the base station 470 to access from among the plurality of base stations 470-1, 470-2, and 470-3.

[0380] <Second-1 Method> As the second-1 method, make the time interval occupied by Frame 2300-1 (Frame #1) of FIG. 28 longer than that of a frame in a video or a still image.

[0381] For example, the symbol 2301-1 regarding the SSID in FIG. 28 may contain a plurality of "SSID information of Base Station #1" (that is, the "SSID information of Base Station #1" is repeatedly included), and the symbol 2302-1 regarding the encryption key may contain a plurality of "encryption key information of Base Station #1 (encryption key information for connecting to Base Station #1)" (that is, the "encryption key information of Base Station #1 (encryption key information for connecting to Base Station #1)" is repeatedly included).

[0382] By doing so, the terminal 1050 can prevent receiving modulation signals including different SSIDs and encryption keys, such as "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", within one frame of a video or a still image from the fifth device 1000. Therefore, the terminal 1050 can easily select the base station 470 to access from among the plurality of base stations 470-1, 470-2, and 470-3.

[0383] Similarly, "Frame #2 Group Transmission" 2602-1 and 2602-2 may have the following configuration.

[0384] <The first to second method> As the first to second method, by including a plurality of the frame 2300-2 (frame #2) in FIG. 29 in each of the "frame #2 group transmissions" 2602-1 and 2602-2, the time interval occupied by the "frame #2 group transmission" is made longer than the frame in the moving image or still image.

[0385] <The second to second method> As the second to second method, the time interval occupied by the frame 2300-2 (frame #2) in FIG. 29 is made longer than the frame in the moving image or still image.

[0386] For example, the symbol 2301-2 regarding the SSID in FIG. 29 includes a plurality of "information on the SSID of base station #2" (that is, "information on the SSID of base station #2" is repeatedly included), and the symbol 2302-2 regarding the encryption key includes a plurality of "information on the encryption key of base station #2 (information on the encryption key for connecting to base station #2)" (that is, "information on the encryption key of base station #2 (information on the encryption key for connecting to base station #2)" is repeatedly included). Such a configuration may be adopted.

[0387] Similarly, the "frame #3 group transmissions" 2603-1 and 2603-2 may have the following configuration.

[0388] <The first to third method> As the first to third method, by including a plurality of the frame 2300-3 (frame #3) in FIG. 30 in each of the "frame #3 group transmissions" 2603-1 and 2603-2, the time interval occupied by the "frame #3 group transmission" is made longer than the frame in the moving image or still image.

[0389] <The second to third method> As the second to third method, the time interval occupied by the frame 2300-3 (frame #3) in FIG. 30 is made longer than the frame in the moving image or still image.

[0390] For example, the symbol 2301-3 regarding the SSID in FIG. 30 includes a plurality of "information on the SSID of base station #3" (that is, the "information on the SSID of base station #3" is repeatedly included), and the symbol 2302-3 regarding the encryption key includes a plurality of "information on the encryption key of base station #3 (information on the encryption key for connecting to base station #3)" (that is, the "information on the encryption key of base station #3 (information on the encryption key for connecting to base station #3)" is repeatedly included). Such a configuration may be adopted.

[0391] Next, the effects when the fifth device 1000 transmits a frame as shown in FIGS. 28 to 31 will be described.

[0392] As an example, consider the area 2700 in FIG. 32. In FIG. 32, the fifth device 1000 is arranged at the positions of "○" 2701-1, 2701-2, 2701-3, 2701-4, 2701-5, 2701-6, 2701-7, 2701-8, 2701-8, 2701-9, 2701-10. Also, base station 470-1 (base station #1) is arranged at the position of "◎" 2702-1, base station 470-2 (base station #2) is arranged at the position of "◎" 2702-2, and base station 470-3 (base station #3) is arranged at the position of "◎" 2702-3.

[0393] And, for example, assume that there are 99 terminals (hereinafter simply referred to as terminal 1050) having the same configuration as that of terminal 1050 inside area 2703.

[0394] At this time, for example, the fifth devices 1000 arranged at the positions of "○" 2701-5 and 2701-10 both transmit the information on the SSID of base station 470-3 (base station #3) and the information on the encryption key for accessing base station 470-3 (base station #3). This is because the base station closest to the positions of "○" 2701-5 and 2701-10 is base station 470-3 (base station #3).

[0395] In this case, all 99 terminals 1050 will access the base station 470-3 (Base Station #3). Then, due to access concentration, it is highly likely that there will be terminals 1050 that have difficulty accessing the base station 470-3 (Base Station #3).

[0396] Considering this point, by performing control so that the 99 terminals 1050 access the base station 470-1 (Base Station #1) (the position of "◎" 2702-1), the base station 470-2 (Base Station #2) (the position of [◎] 2702-2), and the base station 470-3 (Base Station #3) (the position of [◎] 2702-3) as evenly as possible, it is possible to reduce the existence of terminals 1050 that have difficulty accessing the base station 470 as described above.

[0397] For example, since the timing at which the 99 terminals 1050 access the fifth device 1000 generally differs, when the fifth device 1000 transmits frames as shown in FIGS. 28 to 31 as in this embodiment, the 99 terminals 1050 will each obtain one of the SSIDs and encryption keys of the base stations 470-1, 470-2, or 470-3 according to the timing at which they access the fifth device 1000. As a result, "control is performed so that the 99 terminals 1050 access the base stations 470-1, 470-2, and 470-3 as evenly as possible." Therefore, it is possible to reduce the existence of terminals 1050 that have difficulty accessing the base station 470 as described above.

[0398] Note that FIG. 31 shows an example of the transmission method when the fifth device 1000 transmits "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". However, the transmission method when the fifth device 100 transmits "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" is not limited to this.

[0399] For example, in FIG. 31, the fifth device 1000 is shown to repeatedly transmit in the order of "Frame #1 group transmission", "Frame #2 group transmission", and "Frame #3 group transmission". However, "Frame #1 group transmission", "Frame #2 group transmission", and "Frame #3 group transmission" do not necessarily need to be transmitted in the order shown in FIG. 31. Or, for example, the fifth device 1000 may transmit "Frame group 1 transmission", "Frame group #2 transmission", and "Frame group #3 transmission" randomly in time, or may transmit the order of "Frame group 1 transmission", "Frame group #2 transmission", and "Frame group #3 transmission" in a regular order different from that in FIG. 31. At least, it is sufficient that the fifth device 1000 transmits "Frame #1 group transmission", "Frame #2 group transmission", and "Frame #3 group transmission".

[0400] Also, in FIG. 31, the fifth device 1000 continuously transmits "Frame #1 group transmission", "Frame #2 group transmission", and "Frame #3 group transmission", but it does not necessarily have to be transmitted continuously. For example, in FIG. 31, there may be a time interval between Frame #1 group 2601-1 and Frame #2 group transmission 2602-2.

[0401] Also, in FIG. 31, it is only composed of "Frame #1 group transmission", "Frame #2 group transmission", and "Frame #3 group transmission", but other symbols and other frames may exist. Further, in FIGS. 31 and 27, the number of base stations 470 is set to three, but the number of base stations 470 is not limited to this. Even when the number of base stations 470 is two or more, the base stations 470 can operate in the same manner as when there are three base stations 470. Therefore, for example, when there are N base stations 470 (N is an integer of 2 or more), when the fifth device 1000 performs the transmission as shown in FIG. 31, "Frame #k group transmission" will exist. Note that k is an integer from 1 to N. And "Frame #k group transmission" includes a symbol related to the SSID (information on the SSID of base station #k) and a symbol related to the encryption key (information on the encryption key for accessing base station #k).

[0402] The frame configuration of the modulation signal transmitted by the wireless device 453 included in the terminal 1050 in FIG. 27 is the same as the frame configuration of FIG. 17 described in Embodiment 4. That is, as shown in FIG. 17, the wireless device 453 included in the terminal 1050 in FIG. 27 transmits, for example, a preamble 1201, and then transmits a control information symbol 1202 and an information symbol 1203.

[0403] The preamble 1201 is a symbol used by base stations 470-1, 470-2, and 470-3 that receive the modulation signal transmitted by the wireless device 453 of the terminal 1050 to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, and the like.

[0404] The control information symbol 1202 is a symbol that includes data such as, for example, the method of error correction coding, information on the modulation method, information on the frame configuration, and information on the transmission method used to generate the modulation signal. The base stations 470-1, 470-2, and 470-3 perform demodulation of the modulation signal and the like based on the information included in the control information symbol 1202.

[0405] The information symbol 1203 is a symbol for the wireless device 453 of the terminal 1050 to transmit data.

[0406] Note that the wireless device 453 of the terminal 1050 in FIG. 27 may transmit a frame including symbols other than the symbols described in FIG. 17 (for example, a frame including a pilot symbol (reference symbol) in the middle of the information symbol 1203). Also, the frame configuration is not limited to the configuration of FIG. 17, including the order in which the symbols are transmitted. And in FIG. 17, there may be a plurality of symbols in the frequency axis direction, that is, symbols may exist at a plurality of frequencies (a plurality of carriers).

[0407] The frame configuration of the modulation signals transmitted by the base stations 470-1, 470-2, and 470-3 in FIG. 27 is the same as the frame configuration of FIG. 12 described in Embodiment 3. That is, as shown in FIG. 12, the base stations 470-1, 470-2, and 470-3 transmit, for example, a preamble 701, and then transmit a control information symbol 702 and an information symbol 703.

[0408] The preamble 701 is a symbol for the radio device 453 of the terminal 1050 that receives the modulation signals transmitted by the base stations 470-1, 470-2, and 470-3 to perform, for example, signal detection, time synchronization, frame synchronization, frequency synchronization, frequency offset estimation, etc.

[0409] The control information symbol 702 is a symbol that includes data such as, for example, the method of error correction coding, information on the modulation method, information on the frame configuration, and information on the transmission method used to generate the modulation signal. The radio device 453 of the terminal 1050 performs demodulation of the modulation signal based on the information of the control information symbol 702.

[0410] The information symbol 703 is a symbol for the base stations 470-1, 470-2, and 470-3 to transmit data.

[0411] Note that the base stations 470-1, 470-2, and 470-3 may transmit a frame including symbols other than the symbols described in FIG. 12. For example, the base stations 470-1, 470-2, and 470-3 may transmit a frame including a pilot symbol (reference symbol) in the middle of the information symbol 703. Also, the frame configuration is not limited to the configuration of FIG. 12, including the order of transmitting symbols. And in FIG. 12, a plurality of symbols may exist in the frequency axis direction. That is, in FIG. 12, symbols may exist on a plurality of frequencies (a plurality of carriers).

[0412] FIG. 33 is a flowchart showing an example of processing performed by the "fifth device 1000", the "terminal 1050", and the "base station #X". Here, X is 1, 2, or 3.

[0413] First, the fifth device 1000 transmits a modulated signal having the frame configuration of FIG. 31 (ST2801).

[0414] Then, the terminal 1050 receives the modulated signal transmitted by the fifth device 1000, and selects the base station to which the terminal 1050 accesses 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).

[0415] The following is an explanation of this point. The terminal 1050 receives the modulated signal transmitted by the fifth device 1000 in order to access one of the base stations 470. At this time, the terminal 1050 obtains, for example, any one of "frame #1 group transmission", "frame #2 group transmission", and "frame #3 group transmission" in FIG. 31 in one frame of a moving image or a still image. Then, the terminal 1050 determines the base station 470 to which the terminal 1050 accesses from base station 470-1 (base station #1), base station 470-2 (base station #2), and base station 470-3 (base station #3) based on the obtained base station information (for example, SSID).

[0416] Next, the terminal 1050 receives the modulated signal transmitted by the fifth device 1000 and acquires the SSID of base station #X to which the terminal 1050 accesses (ST2803).

[0417] In addition, the terminal 1050 acquires an encryption key used for communication with base station #X to which the terminal 1050 accesses (ST2804).

[0418] Then, the terminal 1050 performs a radio connection with base station #X (ST2805). When the terminal 1050 receives a response from base station #X, the connection between the terminal 1050 and base station #X is completed (ST2806).

[0419] Then, the terminal 1050 transmits the connection destination information to the base station #X using radio waves (ST2807).

[0420] The base station #X obtains information to be transmitted to the terminal 1050 from the network (ST2808).

[0421] Then, the base station #X transmits the obtained information to the terminal 1050 using radio waves, and the terminal 1050 obtains the information (ST2809). The terminal 1050 acquires necessary information from the network via the base station #X when necessary, for example.

[0422] As described above, based on the SSID information and the encryption key information transmitted from the fifth device 1000, the terminal 1050 connects to the base station 470 and obtains information, thereby safely obtaining information via the base station 470 with guaranteed security. This is because when obtaining information from the modulation signal of visible light, since it is visible light, it is easy for the user to determine whether the information source is secure. In contrast, for example, when the SSID is obtained from the modulation signal of the radio wave transmitted by the wireless LAN, it is difficult for the user to identify the device that transmitted the radio wave. Therefore, in terms of ensuring information security, visible light communication is more suitable for obtaining the SSID compared to wireless LAN communication.

[0423] Note that in this embodiment, the case where the fifth device 1000 transmits the encryption key information has been described. However, for example, when the base station 470 is not performing encrypted communication using the encryption key, the fifth device 1000 may not transmit the encryption key information and may transmit only the information regarding the SSID. In this case, it can be similarly implemented by simply deleting the configuration related to the encryption key from the above-described configuration.

[0424] In addition, 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 also not limited to the connection destinations and configurations of base stations 470-1, 470-2, and 470-3 shown in FIG. 27.

[0425] Also, according to this embodiment, even when there are multiple terminals 1050 in a certain area, it is possible to reduce the presence of terminals 1050 that have difficulty accessing the base station 470.

[0426] In FIG. 32, the frame configurations of the modulation signals transmitted by the fifth device 1000 arranged 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 configuration in FIG. 31, the modulation signals transmitted by the fifth device 1000 may each have different frame configurations, or there may be multiple fifth devices 1000 that transmit modulation signals with the same frame configuration.

[0427] (Embodiment 8) In this embodiment, as one application example of the communication method using the above-described optical signal, a case where the communication method using the optical signal is combined with image processing will be described. The communication system according to the embodiment of the present application can also be applied to, for example, communication between automobiles (vehicle-to-vehicle communication) or communication between communication devices installed on or near a road and an automobile (road-to-vehicle communication).

[0428] First, the basic configuration in this embodiment will be briefly described. However, this basic configuration is not limited to automobiles and is also applicable to portable terminals such as smartphones and notebook PCs, and is further applicable to other electronic devices.

[0429] FIG. 34 is a block diagram showing the configuration of a communication device A1000 which is an example of the communication device in the present embodiment. The communication device A1000 includes a light receiving device A1002, a control unit A1004, and a wireless device A1006.

[0430] The light receiving device A1002 receives the optical signal A1001 irradiated from a transmitter (not shown) and / or captures a still image or a moving image, and outputs received data A1003. The control unit A1004 controls other devices included in the communication device A1000, and performs processing on the received data A1003 input from the light receiving device A1002 and the wireless reception data input from the wireless device A1006. The wireless device A1006 wirelessly connects to another communication device A1100 based on the control signal A1005 from the control unit A1004, performs wireless communication, and transmits wireless transmission data and receives wireless reception data. The wireless transmission data and the wireless reception 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.

[0431] When the received data A1003 generated by the light receiving device A1002 includes still image data or moving image data, the control unit A1004 may perform image processing using the still image data or the moving image data. Details of an example of the image processing performed by the control unit A1004 will be described later.

[0432] FIG. 35 is a block diagram showing the configuration of a communication device A2000 which is another example of the communication device in the present embodiment. In FIG. 35, components having the same functions as those of the communication device A1000 shown in FIG. 34 are denoted by the same reference numerals as those in FIG. 34, and the description thereof is omitted. The communication device A2000 is different from the communication device A1000 in that it includes a presentation unit A2003 and an input unit A2004.

[0433] The control unit A1004 generates an image based on the received light data A1003 and / or the wireless reception data, other input information, information read from the memory, etc., and outputs the generated image as presentation information A2002 to the presentation unit A2003. The presentation information A2002 is information including, for example, image information and character information generated based on the received light data A1003 or other data. The presentation unit A2003 is, for example, a liquid crystal display, a plasma display, an organic EL display, etc. that display an image signal generated from the image information and character information obtained as the presentation information A2002, but is not limited thereto. For example, the presentation information A2002 may be voice information, and the presentation unit A2003 may be a speaker that outputs voice according to the voice information. The input unit A2004 outputs input information A2005 such as information indicating the operation performed by the user and input character information to the control unit A1004 according to the user's operation. The input unit A2004 is, for example, a touch panel, a physical key, a floating touch display, a motion sensor, etc., but is not limited thereto. For example, the input unit A2004 may be a microphone, and the input information A2005 may be voice information.

[0434] Next, the detailed configuration of the light receiving device A1002 will be described.

[0435] 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 in the present embodiment.

[0436] The light receiving device A3000 includes a light receiving unit A3001 and a light receiving signal processing unit A3003. The light receiving unit A3001 has, for example, the same configuration as the light receiving unit 151 in FIG. 6, receives light incident from the outside, and outputs a received signal A3002. The light receiving signal processing unit A3003 sends out, as received light data A1003, a signal obtained by performing a predetermined process on the received signal A3002.

[0437] The predetermined processing performed by the light receiving signal processing unit A3003 on the received signal A3002 includes, for example, demodulation of the modulation signal components included in the received signal A3002, error correction decoding, etc., and outputs the demodulated data A4002 obtained by demodulation as the light receiving data A1003. In another example, the light receiving signal processing unit A3003 generates still image data or moving image data from the received signal A3002 acquired by the light receiving unit A3001 which is an image sensor such as a CMOS or an organic CMOS as the predetermined processing, and outputs the generated still image data or moving image data as the light receiving data A1003. Here, the still image data or the moving image data may be the encoded data encoded using an image compression method or a moving image compression method, or may be uncompressed data. Hereinafter, the details of the configuration example of the light receiving signal processing unit A3003 will be described.

[0438] FIG. 37 shows the configuration of a light receiving signal processing unit A4000 which is an example of the configuration of the light receiving signal processing unit A3003. The light receiving signal processing unit A4000 includes 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 obtained demodulated data A4002 as the light receiving data A1003. The received signal A3002 input to the light receiving signal processing unit A4000 may be a signal acquired by an image sensor such as a CMOS sensor using a sampling method for receiving an optical signal such as the above-described line scan sampling, an application example of line scan sampling, sampling by a frame, etc., or may be a signal sampled at a sampling rate required for receiving an optical signal using an element different from an image sensor that can convert an optical signal into an electrical signal, such as a photodiode.

[0439] FIG. 38 shows the configuration of a light reception signal processing unit A5000, which is another example of the configuration of the light reception signal processing unit A3003. The light reception signal processing unit A5000 includes an image data generation unit A5001, and outputs image data A5002 including information of an optical signal as received data A1003. That is, the image data generation unit A5001 generates still image data or moving image data from the reception signal A3002, and outputs the generated image data A5002, which is the still image data or the moving image data, as the received data A1003.

[0440] In the following description, for the sake of simplicity, an example in which the image data A5002 is moving image data will be described without particular mention. However, it goes without saying that the moving image data in the following description can be replaced with still image data, or a combination of moving image data and still image data, and the same can be implemented.

[0441] When the light receiving device A1002 includes the light reception signal processing unit A5000, the light receiving unit A3001 is an image sensor such as a CMOS sensor. The light receiving device A1002 controls the operation of the light receiving unit A3001, for example, acquires the reception signal A3002 using a sampling method for receiving an optical signal in the first period of FIG. 39, and acquires the reception signal A3002 using an imaging method for moving image shooting in the second period of FIG. 39.

[0442] Hereinafter, a signal acquired using a sampling method for receiving an optical signal will be referred to as an imaging signal for optical communication, and a signal acquired using an imaging method for moving image shooting will be referred to as an imaging signal for moving image. Further, data generated by the image data generation unit A5001 from the imaging signal for optical communication will be referred to as imaging data for optical communication, and data generated from the imaging signal for moving image will be referred to as imaging data for moving image.

[0443] FIG. 39 shows an example of a method for controlling an image sensor in the case of obtaining both an imaging signal for optical communication and an imaging signal for video in a time-division manner using one image sensor as described above. In the first period of FIG. 39, the light receiving device A1002 obtains an imaging signal for optical communication using the sampling method for receiving an optical signal for the light receiving unit A3001, and in the second period, the light receiving unit A3001 obtains an imaging signal for video using the imaging method for video shooting.

[0444] Here, the first period and the second period are, for example, periods corresponding to one or a plurality of frames in a video. However, the light receiving device A1002 may switch between the sampling method for receiving an optical signal and the imaging method for video shooting at a timing not synchronized with the frames in the video. The light receiving device A1002 may arrange the first period periodically or aperiodically. Also, the rule for arranging the first period, such as the period for arranging the first period, may be dynamically changed.

[0445] Note that the light receiving device A1002 may determine the start time and / or the end time of the first period based on a signal input from the outside. For example, the light receiving device A1002 controls the operation of the light receiving unit A3001 based on the control signal A1007 input from the control unit A1004. At this time, 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 an external transmission device outside the communication devices A1000 and A2000 using a communication method such as wireless communication, wired communication, or optical communication, or data obtained from sensors such as the image sensors provided in the communication devices A1000 and A2000.

[0446] The control information for controlling the operation of the light-receiving unit A3001 may be, for example, a signal specifying rules for arranging the above-described first period and second period, or a signal instructing the light-receiving unit A3001, which normally acquires an imaging signal for video using an imaging method for video shooting, to acquire an imaging signal for optical communication using a sampling method for receiving an optical signal temporarily or continuously. Specific examples will be described later.

[0447] In the above description, an example in which the first period and the second period are arranged alternately has been described, but the control method of the image sensor is not limited to this. For example, a third period in which the CMOS sensor is operated in an imaging method or a sampling method different from any of the methods implemented in the first period and the second period may be arranged, or a transition period for switching the operation of the image sensor may be included between the first period and the second period.

[0448] According to the control method of the image sensor, both an imaging signal for optical communication and an imaging signal for video can be acquired in a time-division format using one image sensor. As a result, the number of image sensors mounted on the communication device can be reduced.

[0449] Note that the light-receiving device A1002 may always operate the light-receiving unit A3001 in a sampling method for receiving an optical signal to acquire the received signal A3002.

[0450] When generating video data A5002, the image data generation unit A5001 may perform encoding processing using a moving image compression method on a video signal composed of a plurality of frames generated from the received signal A3002.

[0451] For example, when the received signal A3002 includes an imaging signal for optical communication and an imaging signal for video, the image data generation unit A5001 may perform moving image compression processing on the frames generated from the imaging signal for video, excluding the images (or frames) generated from the imaging signal for optical communication. At this time, the light receiving device A1002 outputs the encoded moving image data and the image data generated from the imaging signal for optical communication as the received data A1003.

[0452] In the above description, it is assumed that the imaging signal for optical communication is output from the light receiving device A1002 as image data. However, the imaging signal for optical communication may be output from the light receiving device A1002 as any form of data as long as it is data in a format capable of demodulating the optical signal. For example, it may be data in which values obtained by averaging or adding the luminance values of the pixels included in each exposure line, or values obtained by averaging or adding the luminance values of the pixels included in each region obtained by dividing each exposure line into a plurality of regions are arranged in order.

[0453] Note that the moving image 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 video is not limited to the above-described moving image encoding process. For example, the image data generation unit A5001 may perform a common moving image compression process on a moving image including frames composed of the imaging signal for optical communication and frames composed of the imaging signal for video, and the light receiving device A1002 may output the encoded moving image data generated from the imaging signal for optical communication and the imaging signal for video as the received data A1003.

[0454] Next, the operation of the control unit A1004 when the light receiving device A1002 includes the configuration of the light receiving signal processing unit A5000 will be described.

[0455] When the light receiving device A1002 includes the configuration of the light receiving signal processing unit A5000, the light receiving device A1002 does not perform processing such as demodulation and 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 data A1003, and acquires the data transmitted by the optical signal.

[0456] In addition, when the received data A1003 includes imaging data for video in addition to the imaging data for optical communication, the control unit A1004 may perform image processing such as pattern recognition on the imaging data for video in addition to the processing of demodulation and error correction on the optical signal included in the imaging data for optical communication, and further, based on the result of image processing such as pattern recognition, control the light receiving device A1002 or the wireless device A1006.

[0457] As an example of signal processing using the imaging data for video, for example, processing for detecting a part of the body such as a person or a person's face, processing for identifying a person, processing for detecting an object such as a car or a drone, processing for identifying an object such as a car or a drone, processing for detecting the movement or movement of the detected person or object, processing for tracking the detected person or object, etc. can be mentioned. These processes may be performed by extracting feature amounts determined according to the purpose of the signal processing from the imaging data for video and using the extracted feature amounts, or may be performed by a model created by machine learning using a neural network with a multi-layer structure. When using a model created by machine learning using a neural network with a multi-layer structure, preprocessing may be performed on the imaging data for video, and then the preprocessed data may be input to a model created by machine learning using a neural network with a multi-layer structure.

[0458] In the above description, it is assumed that the signal processing performed by the control unit A1004 uses the imaging data for video, but in addition to the imaging data for video, data obtained from audio data or other sensors may be used, or instead of the imaging data for video, data obtained from audio data or other sensors may be used.

[0459] Further, when the light receiving device A1002 includes the configuration of the light receiving signal processing unit A5000 and the light receiving device A1002 outputs the 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 part of or all of the above signal processing.

[0460] Next, an example of the configuration of the light receiving signal processing unit A3003 will be described.

[0461] FIG. 40 shows the configuration of a light receiving signal processing unit A7000, which is a third example of the configuration of the light receiving signal processing unit A3003. The light receiving signal processing unit A7000 includes a reception processing unit A7001 and an image data generation unit A7003.

[0462] The reception processing unit A7001 of the light receiving signal processing unit A7000 has the same function as the reception processing unit A4001 included in the light receiving signal processing unit A4000 described with reference to FIG. 37.

[0463] The image data generation unit A7003 of the light receiving signal processing unit A7000 has the same function as the image data generation unit A5001 included in the light receiving signal processing unit A5000 described with reference to FIG. 38.

[0464] 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 acquire the imaging signal for video and the imaging signal for optical communication as the reception signal A3002. The light receiving signal processing unit A7000 inputs the imaging signal for video 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 input the imaging signal for optical communication to the image data generation unit A5001.

[0465] The light receiving signal processing unit A7000 outputs demodulated data A7002 and video data A7004 as the light receiving data A1003.

[0466] At this time, additional information such as time information indicating the time when the modulation signal corresponding to the demodulated data is received, or metadata may be added to the demodulated data A7002. Here, the time information added to the demodulated data A7002 may be in a format that can identify the relationship with the time information given to the video data A7004. For example, the light reception 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 time line, 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 the offset of the time information of the video data A7004 with respect 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.

[0467] Further, the demodulated data A7002 may include, as additional information or metadata, position information indicating the position in the image of the transmission device or light source that transmitted the modulation signal corresponding to the demodulated data.

[0468] The additional information of the demodulated data A7002 may include both time information and position information, or may include only one of them. Also, the additional information of the demodulated data A7002 may include related information related to the demodulated data other than time information and position information.

[0469] Although the position information has been described as information indicating the position of the transmission device or the light source within the image, it may be other information. For example, it may be information indicating the area within the image used for detecting the optical signal, or it may be information indicating the position in the three-dimensional space. The position information in the three-dimensional space may be, for example, information indicating the direction in which the light receiving device A1002 is taking a picture and the position within the image of the imaging data for the moving picture, or it may be information indicating the values or areas of the coordinates in the coordinate system centered on the light receiving device or the communication device estimated from this information. Further, it may be information indicating the values or areas of the coordinates in an arbitrary coordinate system used in, for example, GPS or a three-dimensional map estimated using the position information of the communication device or the light receiving device. Also, when the light receiving device A1002 acquires not only the imaging data for the moving picture but also distance image data indicating the depth to the object being photographed, the position in the three-dimensional space may be estimated using the distance image data in addition to the imaging data for the moving picture.

[0470] The distance image can be acquired, for example, using a TOF (Time-Of-Flight) method, a distance measurement method using stereo parallax, a LIDER (Laser Imaging Detection and Ranging) method, or the like.

[0471] The demodulated data A7002 and the moving picture 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 a plurality of separated data streams or data packet sequences, or the demodulated data A7002 and the moving picture data A7004 may be multiplexed into a data stream in a format capable of storing both, and transmitted to the control unit A1004 of the communication device A1000 or the control unit A1004 of the communication device A2000 as one data stream or data packet sequence.

[0472] FIG. 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.

[0473] The first light receiving unit A8001-1 is an image sensor such as a CCD, a CMOS, or an organic CMOS, and the second light receiving unit A8001-2 is an image sensor such as a CCD, a CMOS, or an organic CMOS, or a device capable of converting an optical signal into an electrical signal such as a photodiode. The light receiving device A8000 operates the first light receiving unit A8001-1 in an imaging method for video shooting to acquire an imaging signal for video as a received signal A8002-1.

[0474] When the second light receiving unit A8001-2 is an image sensor, the light receiving device A8000 operates the second light receiving unit A8001-2 in a sampling method for receiving an optical signal to acquire an imaging signal for optical communication as a received signal A8002-2. On the other hand, when the second light receiving unit A8001-2 is a device capable of converting an optical signal into an electrical signal such as a photodiode, the light receiving device A8000 acquires a received signal A8002-2 sampled at a sampling rate required for receiving an optical signal using the second light receiving unit A8001-2.

[0475] The first light receiving signal processing unit A8003-1 has, for example, the same function as the light receiving signal processing unit A5000 shown in FIG. 38, and outputs image data A8004-1, which is imaging data for video, as received data A1003.

[0476] The second light receiving signal processing unit A8003-2 has, for example, the same function as the light receiving signal processing unit A4000 shown in FIG. 37, and outputs demodulated data A8004-2 as received data A1003. Note that the second light receiving signal processing unit A8003-2 has the same function as the light receiving signal processing unit A5000 shown in FIG. 38, and outputs image data A8004-2, which is imaging data for optical communication, as received data A1003.

[0477] According to this configuration, since the light receiving device A8000 can simultaneously acquire the image data A8004-1 which is imaging data for video and the image data A8004-2 which is demodulated data or imaging data for optical communication, both optical communication and video imaging can be performed without generating a period during which imaging data for video cannot be acquired.

[0478] Note that, although the case where the light receiving device A8000 includes two sets of a light receiving unit and a light receiving signal processing unit has been described as an example, it may include N (where N is an integer of 3 or more) sets of a light receiving unit and a light receiving signal processing unit.

[0479] Also, the first light receiving unit A8001-1 and the second light receiving unit A8001-2 do not necessarily have to be different elements. For example, some pixels of an image sensor may be operated in an imaging mode for video shooting as the first light receiving unit A8001-1 and used for video shooting, and some other pixels of the same image sensor may be operated in a sampling mode for receiving an optical signal as the second light receiving unit A8001-2 and used for optical communication.

[0480] Similarly, when the light receiving device A8000 includes N or more sets of a light receiving unit and a light receiving signal processing unit, the pixels included in the first region of the image sensor may be operated in an imaging mode for video shooting and used for video shooting, and the pixels included in each of the second region to the Nth region of the image sensor may be operated in a sampling mode for receiving an optical signal and used for optical communication. Note that when video shooting and optical communication do not have to be performed simultaneously, any pixels of the image sensor do not have to be operated in an imaging mode for video shooting, and the pixels of the image sensor may be divided into a plurality of regions, and the pixels of each region may be operated in a sampling mode for receiving an optical signal to perform a plurality of optical communications in parallel.

[0481] Note that when performing video shooting or optical communication using an image sensor, it is not always necessary to operate all pixels, and it may include pixels that are not operated temporarily or continuously, that is, elements in which the charge accumulated by receiving light is not read out.

[0482] Next, an example of controlling an image sensor when receiving a plurality of optical signals simultaneously using the image sensor will be shown with reference to FIG. 42.

[0483] (A) of FIG. 42 shows a state in which four light sources A - D that transmit different optical signals are included in a shooting range that can be shot when using an imaging method for video shooting. The squares within the shooting range of (A) of FIG. 42 each correspond to one pixel.

[0484] At this time, the light receiving device A8000 determines regions A to D each including the light sources A - D as shown in (B) of FIG. 42, for example, and operates the pixels included in each region in a sampling method for receiving the optical signal for each region from region A to region D to acquire the optical signal.

[0485] 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.

[0486] (Example of line scan sampling for each region) A case of performing line scan sampling by forming one line with four pixels arranged in the vertical direction (column direction) in region A as shown in (C) of FIG. 42 will be described. At this time, region A is composed of five lines. The light receiving device acquires the change in the luminance or color of the modulated optical signal by shifting the exposure period for each line for the five lines in region A and performing exposure. However, the size of each region, that is, 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 can be any number. Also, the size of the region for performing sampling for optical communication may be changed according to the size, position, and mutual positional relationship of each light source within the screen. And in the example of (C) of FIG. 42, one line is formed with four pixels arranged in the column direction, but for example, one line may be formed with five pixels arranged in the row direction, and in the case of (C) of FIG. 42, it may be considered that there are four lines in the row direction.

[0487] In the light receiving device, in the region A of (C) in FIG. 42, after reading the signal of Line1 which is the leftmost line of the region A, the signal of the line immediately to the right of the line read immediately before is read in order. When the reading of the signal of Line5 which is the rightmost line of the region A is completed, it returns to Line1 which is the leftmost line, and the process of reading the signal line by line is repeated.

[0488] The light receiving device also performs line scan sampling by acquiring signals in the same process as in region A in each of regions B to D in (B) of FIG. 42. Here, the light receiving device may expose the leftmost lines of all regions at the same time or at different times. Also, the lines of region A and region C located in the same column on the image sensor may be exposed during the same exposure period, and the lines of region B and region D located in the same column on the image sensor may be exposed during the same exposure period. However, regions A to D include lines that are exposed during the same exposure period.

[0489] Here, the case where a plurality of pixels arranged in the vertical direction (column direction) are regarded as one line and exposed during the same period, and the signal is read line by line has been described, but line scan sampling may be performed by regarding a plurality of pixels arranged in the horizontal direction (row direction) as one line.

[0490] In the above description, the case where at least one pixel included in the image sensor is used for both video shooting and optical communication, and whether to acquire the signal in the imaging method for video shooting or the sampling method for optical communication is switched has been described, but the configuration of the light receiving device including the image sensor is not limited to this. For example, the image sensor may be provided with pixels used for optical communication separately from the pixels used for video shooting.

[0491] When the image sensor is provided with pixels used for optical communication separately from the pixels used for video shooting, 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 shooting.

[0492] In addition, the video shooting using pixels for video shooting and the sampling for optical communication using pixels for optical communication are independently controlled. In a situation where one of the processes is unnecessary, either one of the processes is stopped, and the power supply to the circuit for acquiring the signals required for the process is partially or completely stopped to suppress power consumption.

[0493] As described above, by performing line scan sampling, as shown in Fig. 42(A), different modulation signals from a plurality of light sources can be received in parallel, so that the effect of improving the data transmission speed can be obtained.

[0494] 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.

[0495] Fig. 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, data necessary for the processes performed by the control unit, and the like. The CPU A10001 performs processes based on, for example, programs read from the memory A10002, and realizes the functions as the control unit A1004. In addition, the memory A10002, for example, stores data such as image data acquired by the receiving device and reads out the stored data.

[0496] Here, the CPU and memory have been described as elements constituting the control unit A10000, but other components may also be included. For example, a GPU (Graphics Processing Unit) may be provided separately from the CPU, or a circuit for performing image processing such as moving image encoding processing, moving image decoding processing, and pattern recognition on imaging data for video may be provided. Further, the control unit A10000 may include an I / O (Input / Output) for controlling data transfer between the control unit A10000 and devices connected thereto, such as the wireless device A1006.

[0497] FIG. 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 includes a signal processing unit A11002, a wireless control unit A11004, and a light receiving device control unit A11006.

[0498] The signal processing unit A11002 acquires image data including imaging data for optical communication as received data A1003 from the light receiving device A1002, or demodulated data obtained by demodulating and error-correcting an optical signal. When the received data A1003 is image data including imaging data for optical communication, the signal processing unit A11002 acquires a received signal corresponding to a modulation signal from the imaging data for optical communication, and performs demodulation and error-correction processing on the received signal to obtain demodulated data.

[0499] The wireless control unit A11004 outputs a control signal A1005 for controlling the operation of the wireless device A1006 to 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.

[0500] The signal processing unit A11002 performs signal processing using arbitrary data such as demodulated data of optical communication, moving image capture data, and wireless reception data acquired via the light receiving device A1002 and the wireless device A1006. For example, based on the result of the signal processing described above, the signal processing unit A11002 gives an instruction to control the wireless device A1006 to the wireless control unit A11004 and an instruction to control the light receiving device to the light receiving device control unit A11006 (A11005).

[0501] The light receiving device control unit A11006 controls the light receiving device A1002 based on an instruction from the signal processing unit A11002. As an example of the control for the light receiving device A1002, control is performed on whether to acquire a signal using an imaging method for video shooting for the light receiving units A3001, A8001-1, and A8001-2 or to acquire a signal using a sampling method for receiving an optical signal, and setting of a pixel region to be operated in the sampling method for receiving an optical signal when acquiring a signal using the sampling method for receiving an optical signal using some pixels provided in the image sensor. However, the control for the light receiving device A1002 is not limited to this, and for example, control for switching the ON and OFF of the power supply of the light receiving device A1002 or control for switching the signal processing for the received optical signal performed inside the light receiving device A1002 may be performed. Also, some of the controls described here may be automatically performed based on the result of the signal processing for the received optical signal inside the light receiving device A1002.

[0502] FIG. 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 is different from the control unit A11000 in that it has a device control unit A12002.

[0503] The machine control unit A12002 takes the video imaging data acquired by the signal processing unit A11002 and the processing result of the signal processing unit A11002 as inputs (A12001), generates an image to be displayed on the presentation unit A2003, and outputs the generated image signal to the presentation unit A2003 as presentation information A2002. The machine control unit A12002 acquires the input information A2005 acquired by the input unit A2004 according to the user's operation on the input unit A2004, and transfers it to the signal processing unit A11002.

[0504] With this configuration, the signal processing unit A11002 can perform signal processing based on the demodulated data of optical communication, video imaging data, wireless reception data acquired via the light receiving device A1002 and the wireless device A1006, and the input information A2005 acquired according to the user's operation. For example, based on the result of the signal processing described above, the signal processing unit A11002 gives instructions for controlling the wireless device A1006 to the wireless control unit A11004, instructions for controlling the light receiving device to the light receiving device control unit A11006 (A11005), and instructions for changing the image to be displayed on the presentation unit A2003.

[0505] Hereinafter, as an example of the processing performed by the control unit A1004, a communication control method for controlling the wireless device A1006 based on the demodulated data obtained by receiving an optical signal and the result of performing image processing such as pattern recognition on the imaging data for video will be described.

[0506] The signal processing unit A11002 acquires imaging data for video as light reception data A1003 from the light receiving device A1002, and performs image processing such as pattern recognition on the imaging data for video. The wireless control unit A11004 controls the wireless device A1006 based on the result of the image processing in the signal processing unit A11002.

[0507] In the communication control method described in this embodiment, demodulated data obtained by receiving an optical signal is used, along with additional information such as position information indicating the position on an image of a light source used for transmitting the optical signal or a transmitter that transmitted the optical signal, in the form of demodulated data with the additional information associated therewith. In this embodiment, the information transmitted using optical communication can be anything and is not limited to the transmission of specific information. However, in the following description regarding this communication control method, as an example, the case where connection information including information necessary for connection or communication with other wireless communication devices such as the SSID of a base station described in Embodiments 3 to 7 is transmitted by an optical signal will be described.

[0508] The signal processing unit A11002 performs processing using the demodulated data with the additional information obtained inside the light receiving device A1002 or the signal processing unit A11002. Here, the demodulated data is connection information corresponding to other wireless communication devices. When there are multiple pieces of acquired connection information, the signal processing unit A11002 controls the communication processing performed by the wireless device A1006 using the additional information corresponding to each piece of connection information and the result of image processing such as pattern recognition.

[0509] Hereinafter, a first example of communication control based on the result of image processing will be described.

[0510] In the first example of communication control based on the result of image processing, the communication devices A1000 and A2000 are vehicles or devices mounted on a vehicle, and a camera mounted on the vehicle is used as the light receiving device A1002. FIG. 46 schematically shows an example of an image captured by a camera that captures the front of the vehicle. In FIG. 46, three other vehicles A13001, A13002, and A13003 traveling in front of the vehicle corresponding to the communication devices A1000 and A2000 are shown.

[0511] Note that in this embodiment, an example using a camera that captures the front of the vehicle is described, but it goes without saying that the same applies to cameras that capture the rear or side of the vehicle.

[0512] Here, the other vehicles A13001, A13002, and A13003 each include a light source such as an LED and a transmitter 102 that transmits an optical signal using the light source. As the light source used for optical communication, for example, any light source equipped in a vehicle such as a headlight or a taillight can be used, and which light source among the multiple light sources equipped in the vehicle is used for transmitting the optical signal can be arbitrarily designed according to the usage form of optical communication. Further, when multiple light sources equipped in the vehicle are used for transmitting optical signals, the vehicle may be provided with a transmitter for optical communication for each of the multiple light sources, or one transmitter may transmit an optical signal using multiple light sources. Note that the vehicle may be provided with a light source used for optical communication separately from the headlight and the taillight.

[0513] In addition to the transmitter for optical communication and the light source, the other vehicles A13001, A13002, and A13003 are equipped with a communication device for wireless communication that corresponds to the other communication device A1100 described with reference to FIGS. 34 and 35. Note that when the host vehicle and the other vehicles A13001, A13002, and A13003 have functions of transmitting and receiving optical signals and wireless communication, each vehicle has a configuration including a transmitter 102 for optical communication and a light source 104 in the communication devices A1000 and A2000. In this case, the control unit A1004 may control the data transmitted by the transmitter 102.

[0514] In the first example of communication control based on the result of image processing, the other vehicles A13001, A13002, and A13003 transmit connection information, which is information that can be used to connect to the communication devices provided in each vehicle by optical communication. Hereinafter, a case where the connection information includes information indicating the SSID and the frequency channel used for communication when the communication device provided in each vehicle operates as a base station will be described.

[0515] In the above description, an example of notifying the SSID as an identifier for determining a communication partner included in the connection information has been described. However, the identifier information included in the connection information is not limited to the SSID. For example, it may be a physical address such as the MAC (Media Access Control) address of another communication device, or a logical address such as the IP (Internet Protocol) address of another communication device. Note that when the identifier information is not used for selecting another communication device with which the communication device directly communicates, but for selecting a resource accessed via a network such as the Internet, it may be the address of a server that communicates via a network such as the Internet, or a URL (Uniform Resource Locator), URN (Uniform Resource Name), URI (Uniform Resource Identifier), etc. used to identify a resource on the Internet. Any information may be used as long as the identifier information included in the connection information can identify another communication terminal serving as an access destination or a resource on the Internet.

[0516] In the above description, a case of notifying information on the frequency channel used by the connection information has been described. However, the connection information may not include information on the frequency channel being used, or may include other information. Examples of other information that can be used as connection information include information regarding an encryption key, the type of standard for the transmission method of the corresponding physical layer, the corresponding data format, communication protocol, and the like.

[0517] FIG. 47 is a diagram schematically showing connection information obtained by demodulating optical signals transmitted by the respective transmission units of other vehicles A13001, A13002, and A13003 using a light source 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 that the SSID is "XXX" and the frequency channel in use is "1" from the optical signal transmitted by the other vehicle A13001, obtain connection information that the SSID is "YYY" and the frequency channel in use is "3" from the optical signal transmitted by the other vehicle A13002, and obtain connection information that the SSID is "ZZZ" and the frequency channel in use is "3" from the optical signal transmitted by the other vehicle A13003.

[0518] Some of these connection information can be replaced by information that can be obtained by the wireless device A1006 provided in the communication devices A1000 and A2000 performing carrier sense over a certain period and receiving signals transmitted from each of a plurality of other communication devices. However, it is difficult for the communication devices A1000 and A2000 to identify from which of the plurality of other communication devices existing in the vicinity the signals are transmitted, and there is a possibility of connecting to and communicating with a communication device different from the other communication device with which actual communication is desired.

[0519] Therefore, in the first example of communication control based on the result of image processing, the control unit A1004 of the communication devices A1000 and A2000 performs image processing on the imaging data for the moving image captured by the light receiving device A1002, and detects each of the other vehicles A13001, A13002, and A13003 from the image of FIG. 46, for example. At this time, the control unit A1004 associates each of the other vehicles A13001, A13002, and A13003 detected from the image with the three connection information received by optical communication based on the positions of the light sources of the three received optical signals. Thereby, the connection information to be used when performing wireless communication with each of the three vehicles detected from the image can be specified.

[0520] Next, the control unit A1004 determines the mutual positional relationship between other vehicles A13001, A13002, A13003 and the positional relationship between each vehicle and the host vehicle from the image, and selects a target for wireless communication. For example, the control unit A1004 may select the other vehicle A13003 that is closest to the host vehicle as the communication target. Further, the control unit A1004 determines the lane in which each vehicle is traveling, and may select the other vehicle A13001 that is traveling at the foremost position in the image among the vehicles traveling in the lane in which the host vehicle is traveling as the communication partner.

[0521] According to this configuration, it is possible to associate information that is difficult to associate with a device in the real space only by wireless communication, such as an identifier such as an SSID or an address in wireless communication, with an object 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 movement of surrounding vehicles for the purpose of controlling autonomous driving including driving support, it promotes facilitating connection to an appropriate communication partner as an information acquisition destination.

[0522] Next, a second example of communication control based on the result of image processing will be described.

[0523] In the second example of communication control based on the result of image processing, the configurations of the communication devices A1000, A2000 or the host vehicle including the communication devices 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 is different from the first example of communication control based on the result of image processing in that another vehicle A15003 that does not have a function of transmitting an optical signal is traveling instead of the other vehicle A13003.

[0524] FIG. 48 is a diagram schematically showing an example of an image captured by a camera that captures the front of a vehicle in the second example of communication control based on the result of image processing. In FIG. 48, three other vehicles A13001, A13002, A15003 traveling in front of the vehicle corresponding to the communication devices A1000, A2000 are shown.

[0525] FIG. 49 is a diagram schematically showing connection information obtained by demodulating optical signals transmitted by respective transmission units of other vehicles A13001 and A13002 using a light source in a light receiving device A1002 or a control unit A1004 of communication devices A1000 and A2000. The communication devices A1000 and A2000 acquire connection information that the SSID is "XXX" and the frequency channel in use is "1" from the optical signal transmitted by the other vehicle A13001, and acquire connection information that the SSID is "YYY" and the frequency channel in use is "3" from the optical signal transmitted by the other vehicle A13002. At this time, since the other vehicle A15003 does not have a function of transmitting an optical signal, the communication devices A1000 and A2000 cannot acquire connection information regarding the other vehicle A15003.

[0526] In a second example of communication control based on the result of image processing, a control unit A1004 of communication devices A1000 and A2000 performs image processing on imaging data for a moving image captured by a light receiving device A1002, and detects each of other vehicles A13001, A13002, and A15003 from, for example, the image in FIG. 48. At this time, 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 by optical communication with the other vehicles A13001 and A13002 among the other vehicles A13001, A13002, and A15003 detected from the image. Thereby, it is possible to specify connection information to be used when performing wireless communication with the other vehicles A13001 and A13002 detected from the image, and it is possible to specify that a base station or a communication device having an SSID of "XXX" or "YYY" is not an SSID used for communicating with the other vehicle A15003.

[0527] First, a case will be described in which the other vehicle A15003 does not have a function of transmitting an optical signal but has a function of performing wireless communication using an SSID of "PPP".

[0528] At this time, the wireless device A1006 detects three SSIDs, namely, "XXX", "YYY", and "PPP", as the SSIDs of other communication devices mounted on vehicles within a communicable distance by performing carrier sense. The control unit A1004 determines that "PPP", which is different from "XXX" and "YYY" included in the connection information received as an optical signal, is the SSID to be used for communicating with another vehicle A15003, and associates the other vehicle A15003 with the SSID "PPP".

[0529] The control unit A1004 determines the mutual positional relationships among other vehicles A13001, A13002, and A15003 and the positional relationships between each vehicle and the host vehicle from the image, and selects a target for performing wireless communication. For example, the control unit A1004 may select the other vehicle A15003 that is closest to the host vehicle as the communication target. Further, the control unit A1004 may determine the lane in which each vehicle is traveling, and select the other vehicle A13001 that is traveling in the most forward position in the image among the vehicles traveling in the lane in which the host vehicle is traveling as the communication partner.

[0530] According to this configuration, it is possible to associate information such as identifiers such as SSIDs and addresses in wireless communication, which is difficult to associate with devices in the real space only by wireless communication, with an object detected by signal processing such as pattern recognition from sensing data obtained by a sensor such as an image obtained by an image sensor. As a result, for example, when acquiring information such as the surrounding environment and the movement of surrounding vehicles for the purpose of controlling autonomous driving including driving support, it promotes facilitating connection to an appropriate communication partner as an information acquisition destination.

[0531] Next, a case where the other vehicle A15003 does not have both a function of transmitting an optical signal and a function of performing wireless communication will be described.

[0532] At this time, the wireless device A1006 detects two SSIDs, "XXX" and "YYY", as the SSIDs of other communication devices mounted on vehicles within a communicable distance by performing carrier sense. Since the control unit A1004 does not detect an SSID different from "XXX" and "YYY" included in the connection information received as an optical signal as the SSID of other communication devices mounted on the vehicle, it is determined that the other vehicle A15003 does not have a function of performing wireless communication or is not in a relationship where wireless communication can be performed.

[0533] The control unit A1004 determines the mutual positional relationships of the other vehicles A13001, A13002, and A15003 and the positional relationships between each vehicle and the host vehicle from the image, and selects either the other vehicle A13001 or the other vehicle A13002 as a target for performing wireless communication. For example, the control unit A1004 may select, as a communication target, the other vehicle A13002 that is the closest to the host vehicle and communicable. Further, the control unit A1004 determines the lane in which each vehicle is traveling, and may select, as a communication partner, the other vehicle A13001 that is traveling in the most forward position in the image among the vehicles traveling in the lane in which the host vehicle is traveling.

[0534] According to this configuration, it is possible to associate information that is difficult to associate with a device in the real space only by wireless communication, such as identifiers such as SSIDs and addresses in wireless communication, with an object 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, it can be determined that information cannot be acquired by communication with the other vehicle A15003 that was traveling immediately before, and for example, when performing control of autonomous driving including driving support, it is possible to prevent misidentifying the communicable other vehicles A13001 and A13002 as the other vehicle A15003, and to promote the provision of appropriate autonomous driving control.

[0535] Next, a third example of communication control based on the result of image processing will be described.

[0536] In a third example of communication control based on the result of image processing, the configurations of the communication devices A1000 and A2000, or the vehicle equipped with the communication devices A1000 and A2000, and the configurations of other vehicles A13002 and A13003 are the same as those in the first example of communication control based on the result of image processing. In the third example of communication control based on the result of image processing, it is different 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. The police vehicle A17001 is different from the other vehicle A13001 in that it is a police vehicle, but has the same configuration as the other vehicle A13001 and has functions of transmitting optical signals and wireless communication.

[0537] FIG. 50 is a diagram schematically showing an example of an image captured by a camera that captures the front of a vehicle in a third example of communication control based on the result of image processing. In FIG. 50, other vehicles A13002 and A13003 and a police vehicle A17001 traveling in front of the vehicle corresponding to the communication devices A1000 and A2000 are shown.

[0538] FIG. 51 is a diagram schematically showing connection information obtained by demodulating optical signals transmitted by the respective transmission units of other vehicles A17001, A13002, and A13003 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 that the SSID is "QQQ" and the frequency channel in use is "1" from the optical signal transmitted by the police vehicle A17001, obtain connection information that the SSID is "YYY" and the frequency channel in use is "3" from the optical signal transmitted by the other vehicle A13002, and obtain connection information that the SSID is "ZZZ" and the frequency channel in use is "3" from the optical signal transmitted by the other vehicle A13003.

[0539] In the third example of communication control based on the result of image processing, the control units A1004 of the communication devices A1000 and A2000 perform image processing on the imaging data for the moving image captured by the light receiving device A1002, and detect, for example, the police vehicle A17001 and the other vehicles A13002 and A13003 from the image in FIG. 50. At this time, based on the positions of the light sources of the three received optical signals, the control unit A1004 associates the three connection information received by optical communication with the police vehicle A17001 and the other vehicles A13002 and A13003 detected from the image. Thereby, for each of the police vehicle A17001 and the other vehicles A13002 and A13002 detected from the image, the connection information to be used when performing wireless communication can be specified.

[0540] For the three vehicles recognized in the image processing, the control unit A1004 performs a detailed classification of the vehicles, such as whether they are police vehicles, using information such as the appearance of the vehicles, and recognizes that the vehicle A17001 is a police vehicle. The control unit A1004 selects the police vehicle A17001 with a high priority for obtaining information among the police vehicle A17001 and the other vehicles A13002 and A13003 as the target for performing wireless communication.

[0541] According to this configuration, when recognizing an object by signal processing such as pattern recognition from sensing data obtained by a sensor such as an image obtained by an image sensor, the recognized object can be further classified in detail, and communication control can be performed based on the classification.

[0542] Note that the control of selecting the police vehicle described above as the communication partner with a high priority for information acquisition is merely an example, and different control may be performed when a police vehicle is recognized. For example, the police vehicle A17001 transmits an identifier for identifying the police vehicle in the optical signal, and the control unit A1004 does not directly wirelessly connect to the police vehicle, but designates the identifier received by the optical signal from the police vehicle A17001 to the other vehicle A13002 or the other vehicle A13003 to obtain the information of the police vehicle A17001.

[0543] In addition, when a police vehicle is detected by image processing, instead of always performing the same communication control, 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 the image sensor, and the control unit A1004 detects a siren sound by performing signal processing of pattern recognition on the voice data acquired by the microphone, communication control that prioritizes information collection regarding the police vehicle may be performed.

[0544] In addition, when detecting a sound generated by another device using the voice data acquired by the microphone, a modulation signal generated based on transmission data such as an identifier of the other device may be transmitted simultaneously.

[0545] According to this configuration, it is possible to associate the device that generated the sound recognized by signal processing such as pattern recognition with transmission data such as an identifier transmitted as the sound signal. As a result, for example, in an environment where there are a plurality of devices with known identifiers, it may be possible to easily identify the device that generated the detected sound.

[0546] In addition, a sound signal may be used instead of the optical signal. In that case, the light receiving device A1002 in the communication devices A1000 and A2000 is replaced with a sound detection device such as a microphone. Further, by using a device such as an array microphone that can specify the direction of arrival of sound as the sound detection device, the association between the device that generated the sound to be detected and the sound signal can be made more accurate.

[0547] In addition, the communication devices A1000 and A2000 according to the present embodiment may have a plurality of wireless devices. For example, the communication devices A1000 and A2000 may include a plurality of wireless devices corresponding to communication methods defined by different standards, or may include a plurality of wireless devices corresponding to the same communication method.

[0548] Further, when the communication devices A1000 and A2000 according to the present embodiment are vehicles or 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 rear monitor, a camera for checking the periphery of the vehicle body, a camera used to display an image instead of a side mirror on a monitor, and the like. In this way, by receiving an optical signal using a camera mounted for purposes other than optical communication, the communication control disclosed in the present embodiment can be realized without adding a new camera, and cost reduction and the spread of the optical signal receiving function can be promoted. Further, since such a camera is installed so as to be able to photograph an area where information necessary for the driver, that is, important information for operating the vehicle can be obtained, by combining signal processing such as image recognition and wireless communication to collect more information, it is possible to provide appropriate automatic driving control and promote the provision of information to the driver.

[0549] In the present disclosure, for example, a method and an apparatus aspect for demodulating a transmission signal transmitted using a communication method receivable by a sensor such as an image sensor or a microphone using sensing data obtained by the sensor are described.

[0550] In the above aspect, further, according to an aspect in which pattern recognition signal processing such as image recognition is performed on the sensing data obtained by the sensor, it becomes possible to determine the correspondence between the object in the real space detected or recognized from the sensing data and the transmission source of the transmission signal.

[0551] In the above aspect, further, according to an aspect in which information such as an SSID, an address, and an identifier used in processing via a network including communication is transmitted using the transmission signal, the association between the information used in processing via a network including communication and the object in the real space can be facilitated. That is, conventionally, information used in processing via a network that was difficult to associate with an object in the real space can be used based on sensing data obtained from the real space.

[0552] In the above aspect, further, according to the 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 association between a visible object and the information used in processing via a network including communication can be improved.

[0553] In the above aspect, further, according to the aspect in which identifiers used for communication such as SSID and address are transmitted as optical signals and an identifier of an object to be connected in communication is selected based on the result of signal processing of image recognition, communication control based on the positional relationship of an object in real space and the attributes of the object can be performed, communication can be performed by designating an object to be connected, and information can be acquired and control instructions can 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 included in the communication range, and the creation and spread of new services via communication can be promoted.

[0554] The above describes Embodiment 8 of the present disclosure.

[0555] Note that, as an example of a communication system that performs visible light communication, the configuration of FIG. 5 has been described, but 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 (for example, refer to "IEEE 802.11-16 / 1499r1"). In FIG. 52, the transmission signal is transmitted as an optical signal in the baseband band without being up-converted. That is, a device that transmits the optical signal of the present embodiment (that is, a device equipped with a light source) may have the configuration on the transmission side shown in FIG. 52, and a terminal that receives the optical signal of the present embodiment may have the configuration on the reception side shown in FIG. 52.

[0556] (Embodiment 9) In the present embodiment, FIG. 52 will be supplemented and explained.

[0557] A specific description of FIG. 52 will be given. The symbol mapping unit inputs transmission data and outputs a symbol sequence (ci) that performs mapping based on the modulation method.

[0558] The pre - equalization processing unit takes 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 symbol sequence after the pre - equalization processing.

[0559] The Hermitian symmetry processing unit takes the symbol sequence after the pre - equalization processing as input, performs sub - carrier allocation on the symbol sequence after the pre - equalization processing so as to ensure Hermitian symmetry, and outputs a parallel signal.

[0560] The inverse (fast) Fourier transform unit takes the parallel signal as input, performs an inverse (fast) Fourier transform on the parallel signal, and outputs the signal after the inverse (fast) Fourier transform.

[0561] The parallel - serial and cyclic prefix addition unit takes the signal after the inverse (fast) Fourier transform as input, performs parallel - serial conversion and adds a cyclic prefix, and outputs it as the signal after signal processing.

[0562] The digital - analog conversion unit takes the signal after signal processing as input, performs digital - analog conversion, outputs an analog signal, and the analog signal is output as light from one or more, for example, LEDs.

[0563] Note that the pre - equalization processing unit and the Hermitian symmetry processing unit may not be provided. That is, the signal processing in the pre - equalization processing unit and the Hermitian symmetry processing unit may not be performed.

[0564] The photodiode takes light as input and obtains a received signal by a TIA (Transimpedance Amplifier).

[0565] The analog - digital conversion unit performs analog - digital conversion on the received signal and outputs a digital signal.

[0566] The cyclic prefix removal and serial-parallel conversion unit takes a digital signal as input, performs cyclic prefix removal, and then performs serial-parallel conversion, taking the parallel signal as input.

[0567] (Fast) Fourier transform unit takes a parallel signal as input, performs (fast) Fourier transform, and outputs the signal after (fast) Fourier transform.

[0568] The detection unit takes the signal after Fourier transform as input, performs detection, and outputs the received symbol sequence.

[0569] The symbol demapper takes the received symbol sequence as input, performs demapping, and obtains the received data sequence.

[0570] As described above, even if the transmission device that transmits the optical modulation signal and the reception device that receives the optical modulation signal are applied to each embodiment in this specification, each embodiment can be similarly implemented.

[0571] (Embodiment 10) In Embodiment 8, an example in the case where the transmission device transmits a plurality of optical modulation signals and the reception device receives a plurality of optical modulation signals was described with reference to FIG. 42. In this embodiment, an example at this time will be described.

[0572] FIG. 53 shows a configuration example of the transmission device and the reception device in this embodiment. In FIG. 53, the transmission device 100 transmits a plurality of optical modulation signals, and the reception device 150 receives a plurality of optical modulation signals to obtain received data. Note that in FIG. 53, those that operate in the same manner as in FIG. 6 are given the same numbers.

[0573] The transmission device in FIG. 53 is assumed to transmit M optical modulation signals. Note that M is an integer of 2 or more.

[0574] The transmission unit A2002_i takes data A2001_i and control signal A2005 as inputs, and based on the information regarding the error correction coding method and the information regarding the transmission method included in the control signal A2005, performs signal processing based on error correction coding and the transmission method to generate and output an optical modulation signal A2003_i. Here, it is assumed that i is an integer from 1 to M inclusive.

[0575] Then, the optical modulation signal A2003_i is transmitted from the light source A2004_i.

[0576] A light receiving unit A2051 such as an image sensor receives the light corresponding to the optical modulation signal A2003_i. At this time, the light receiving unit A2051 will receive the light corresponding to the M optical modulation signals. Regarding the method of receiving the received signals of a plurality of lights in the light receiving unit A2051, for example, it is as described in Embodiment 8.

[0577] The light receiving unit A2051 outputs a light reception signal A2052_i corresponding to the optical modulation signal 2003_i. Here, it is assumed that i is an integer from 1 to M inclusive.

[0578] The receiving unit A2053_i takes the light reception signal A2052_i corresponding to the optical modulation signal A2003_i as an input, performs processes such as demodulation and error correction decoding, and outputs received data A2054_i corresponding to the data A2001_i.

[0579] The data acquisition unit A2055 takes data A2054_1, data A2054_2, ···, data A2054_M as inputs, and generates and outputs data A2056.

[0580] FIG. 54 shows a configuration example of a transmission device and a reception device in this embodiment different from FIG. 53. In FIG. 54, those that operate in the same manner as in FIG. 53 are given the same numbers.

[0581] The distribution unit A2102 takes information A2101 and control signal A2005 as inputs, performs error correction encoding on information A2101 based on the information regarding the error correction encoding method included in control signal A2005, and generates data after error correction encoding. Then, the distribution unit A2102 distributes the data after error correction encoding and outputs the data A2001_i after error correction encoding.

[0582] Note that the distribution to the M pieces of data A2001_i after error correction encoding may be performed in any manner. For example, the data after error correction encoding may be divided into M pieces, and the divided M data sequences may be respectively assigned to the data A2001_i after error correction encoding. Alternatively, M data sequences composed of the same data may be generated from the data after error correction encoding, and each data sequence may be assigned to the data A2001_i after error correction encoding. The method of assignment to the data A2001_i after error correction encoding is not limited to these, and M data sequences may be generated from the data after error correction encoding, and each data sequence may be assigned to the data A2001_i after error correction encoding.

[0583] The transmission unit A2002_i takes data A2001_i and control signal A2005 as inputs, performs signal processing based on the transmission method according to the information regarding the transmission method included in control signal A2005, generates an optical modulation signal A2003_i, and outputs it. Note that i is an integer from 1 to M.

[0584] Then, the optical modulation signal A2003_i is transmitted from the light source A2004_i.

[0585] The light receiving unit A2051 such as an image sensor receives light corresponding to the optical modulation signal A2003_i. At this time, the light receiving unit A2051 will receive light corresponding to the M optical modulation signals. Regarding the method of receiving the reception signals of a plurality of lights in the light receiving unit A2051, for example, it is as described in Embodiment 8.

[0586] The light-receiving unit A2051 outputs an optical reception signal A2052_i corresponding to the optical modulation signal 2003_i. Here, i is an integer from 1 to M inclusive.

[0587] The receiving unit A2053_i takes the optical reception signal A2052_i corresponding to the optical modulation signal A2003_i as input, performs processes such as demodulation, and outputs the received data (log-likelihood ratio) 2054_i corresponding to the data A2001_i.

[0588] The error correction decoding unit A2151 takes as input the received data (log-likelihood ratio) 2054_1, the received data (log-likelihood ratio) 2054_2, ···, the received data (log-likelihood ratio) 2054_M, performs error correction decoding, and outputs the received data A2152.

[0589] FIG. 55 shows an example of the frame configuration of the optical modulation signal transmitted by the transmission device 100 in FIGS. 53 and 54.

[0590] The frame configuration A2201_1 in FIG. 55 shows an example of the frame configuration of the optical modulation signal A2003_1 in FIGS. 53 and 54. In the frame configuration A2201_1, the horizontal axis represents time.

[0591] Therefore, the frame configuration A2201_i in FIG. 55 shows an example of the frame configuration of the optical modulation signal A2003_i in FIGS. 53 and 54. In the frame configuration A2201_i, the horizontal axis represents time. And i is an integer from 1 to M inclusive. (That is, in FIG. 55, M frame configurations are shown.)

[0592] As shown in the frame configuration A2201_i, the transmission device 100 in FIGS. 53 and 54 transmits a preamble A2210_i, a control information symbol A2211_i, and a data symbol A2212_i in the optical modulation signal A2003_i.

[0593] FIG. 56 shows an example of the reception state in the receiving apparatus 150. In the following example, it is assumed that the transmitting apparatus 100 in FIGS. 53 and 54 includes 16 (M = 16) light sources.

[0594] In FIG. 56, A2300 shows an image sensor which is an example of a light receiving unit, and A2301_1 is the light irradiated by the first light source, and it is assumed that the first optical modulation signal is included in this light. Note that the first optical modulation signal corresponds to A2201_1 in FIG. 55.

[0595] Therefore, in FIG. 56, A2301_i is the light irradiated by the i-th light source, and it is assumed that the i-th optical modulation signal is included in this light. Note that the i-th optical modulation signal corresponds to A2201_i in FIG. 55. Here, i is an integer from 1 to 16.

[0596] In the example of the reception state in the receiving apparatus 150 of FIG. 56, the light receiving unit of the receiving apparatus 150 receives the light of the fourth light source including the fourth optical modulation signal, the light of the eighth light source including the eighth optical modulation signal, and the light of the twelfth light source including the twelfth optical modulation signal.

[0597] For example, assuming that the transmitting apparatus 100 in FIGS. 53 and 54 transmits 16 optical modulation signals from 16 light sources, in the state of FIG. 56, the receiving apparatus 150 in FIGS. 53 and 54 cannot receive all 16 optical modulation signals, and thus it is difficult to obtain correct reception data. A method for overcoming this problem will be described below.

[0598] FIG. 57 shows an example of the frame configuration A2201_i of the optical modulation signal A2003_i in FIG. 55, the information included in the preamble A2210_i and the control information symbol A2211_i, and the configuration of the symbol. Here, i is an integer from 1 to M (= 16).

[0599] In the frame configuration A2201_i, the preamble A2210_i and the control information symbol A2211_i shall include the symbol A2401 for signal detection, the symbol A2402 for synchronization, the symbol A2403 including information on the number of optical modulation signals being transmitted, and the symbol A2404 including information on the error correction coding method, the transmission method, and the modulation method, as shown in FIG. 57.

[0600] The symbol A2401 for signal detection is a symbol for the receiving device 150 to know the presence of the optical modulation signal. By detecting this symbol, the receiving device 150 will know that the optical modulation signal is present.

[0601] The symbol A2402 for synchronization is a symbol for 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 and high-precision demodulation of each symbol becomes possible.

[0602] The symbol A2403 including information on the number of optical modulation signals being transmitted is a symbol for the transmitting device 100 to notify the number of optical modulation signals being transmitted. In the state of FIG. 56, the symbol A2403 including information on the number of optical modulation signals being transmitted is transmitting the information "16".

[0603] In the receiving state of FIG. 56, by receiving the symbol A2403 including information on the number of optical modulation signals being transmitted, the receiving device 150 will know that the transmitting device 100 is transmitting "16" optical modulation signals. Note that in the receiving state of FIG. 56, the receiving device 150 will know that it has only received 3 out of the 16 optical modulation signals.

[0604] Symbol A2404, which contains information regarding an error correction coding method, a transmission method, and a modulation method, is, for example, a symbol that contains information regarding the error correction coding method, the transmission method, and the modulation method used in the data symbol (the symbol for transmitting data) of the optical modulation signal A2003_i. By receiving this symbol, the receiving device 150 can know the error correction coding method, the transmission method, and the modulation method used in the optical modulation signal A2003_i.

[0605] In the case of the frame configuration of FIG. 55, from the optical modulation signal A2003_1 to the optical modulation signal A2003_16, the symbols described in FIG. 57 are transmitted by the transmitting device 100. By doing so, as shown in FIG. 56, even when the receiving device 150 has not received all the optical modulation signals, the receiving device 150 can know the number of optical modulation signals transmitted by the transmitting device 100. As a result, the receiving device 150 can know "whether all the optical modulation signals have been received or not". If not all the optical modulation signals have been received, the signal processing can be aborted midway, thereby obtaining the effect of suppressing unnecessary power consumption.

[0606] FIG. 58 shows an example of the preamble A2210_i, the information included in the control information symbol A2211_i, and the symbol configuration of the frame configuration A2201_i of the optical modulation signal A2003_i in FIG. 55, which is different from FIG. 57. Note that i is an integer from 1 to M (= 16). In FIG. 58, those that operate in the same manner as in FIG. 57 are given the same numbers and the description thereof is omitted since it has already been described.

[0607] In FIG. 58, a symbol A2501 that contains information regarding the number of the optical modulation signals is added as a symbol transmitted by the transmitting device 100 compared to FIG. 57.

[0608] FIG. 58 shows the frame configuration A2201_i of the optical modulation signal A2003_i in FIG. 55, that is, the frame configuration of the i-th optical modulation signal. Therefore, the symbol A2501 including information on the number of the optical modulation signal contains the information "i".

[0609] For example, the symbol A2501 included in the optical modulation signal transmitted by the transmission device 100 and including information on the number of the optical modulation signal contains the information "1".

[0610] In the reception state of FIG. 56, the reception device 150 receives the symbol A2403 including information on the number of optical modulation signals being transmitted, and thus knows that the transmission device 100 is transmitting "16" optical modulation signals. Then, the reception device 150 will receive the "symbol A2501 including information on the number of the optical modulation signal" included in the fourth optical modulation signal, the "symbol A2501A including information on the number of the optical modulation signal" included in the eighth modulation signal, and the "symbol A2501A including information on the number of the optical modulation signal" included in the twelfth modulation signal. Therefore, the reception device 150 will know that it has received the fourth optical modulation signal, the eighth optical modulation signal, and the twelfth optical modulation signal. By knowing this situation, the reception device 150 will perform operations to improve the reception situation, thereby improving the reception quality of the data. However, the detailed operations will be described later.

[0611] Another example of the reception state in the reception device 150 is shown in FIGS. 59 and 60. In FIGS. 59 and 60, those that operate in the same manner as in FIG. 56 are given the same numbers and have already been described, so the description will be omitted.

[0612] In the example of the reception state of the reception device 150 in FIG. 59, the light receiving unit A2300 of the reception device 150 receives the light from the first light source including the first optical modulation signal to the light from the sixteenth light source including the sixteenth optical modulation signal, that is, receives 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.

[0613] In the example of the reception state in the receiving device 150 of FIG. 60, the light receiving unit A2300 of the receiving device 150 receives light from the light source of the first light modulation signal to the light source of the 16th light modulation signal including the 16th light modulation signal, that is, receives 16 light modulation signals. In the case of FIG. 60, for example, it is considered that the first light modulation signal is received at the lower right of the light receiving unit A2300, which is different from FIG. 59.

[0614] The reception states of FIGS. 59 and 60 are merely examples, and the situation in which the receiving device 150 receives the 1st to 16th light modulation signals varies depending on the environment. Considering this point, as shown in FIG. 58, since each light modulation signal has a "symbol A2501 including information regarding the number of the light modulation signal", the receiving device 150 can grasp "which part of the light receiving unit and which light modulation signal can be received". Then, the receiving device 150 obtains the i-th received data obtained from the received signal of the i-th light modulation signal, and when it is necessary to rearrange the received data from the 1st to 16th received data, the received data can be identified as "the received data of which light modulation signal" from the "symbol A2501 including information regarding the number of the light modulation signal", so that the received data can be correctly rearranged, thereby improving the reception quality of the data.

[0615] Next, a method of configuring a frame different from the above will be described.

[0616] FIG. 55 shows an example of the frame configuration of the light modulation signal transmitted by the transmitting device 100 in FIGS. 53 and 54, and the description thereof will be omitted since it has already been described.

[0617] For example, the preamble and the configuration of control information symbols in the frame configuration A2201_1 of the optical modulation signal A2003_1 in FIG. 55 are shown in FIG. 57, and the preambles and the configurations of control information symbols from the "frame configuration A2201_2 of the optical modulation signal A2003_2" to the "frame configuration A2201_16 of the optical modulation signal A2003_16" are shown in FIG. 61. In FIG. 61, those that operate in the same manner as in FIG. 57 are given the same numbers, and the characteristic point of FIG. 61 is that it does not include the "symbol A2403 containing information on the number of optical modulation signals being transmitted". That is, the transmission device 100 transmits the "symbol A2403 containing information on the number of optical modulation signals being transmitted" only in the optical modulation signal A2003_1.

[0618] At this time, in the case of the reception state of the reception device 150 in FIG. 56, since the reception device 150 has not obtained the "symbol A2403 containing information on the number of optical modulation signals being transmitted", it cannot grasp the number of optical modulation signals transmitted by the transmission device 100. Then, the reception device 150 determines that it is difficult to correctly receive the data, stops the signal processing of the reception operation, and can suppress unnecessary power consumption.

[0619] Note that in the description of this example, it is described that "the transmission device 100 transmits the'symbol A2403 containing information on the number of optical modulation signals being transmitted' only in the optical modulation signal A2003_1", but this is not limited to this example. As long as "the transmission device 100 transmits the'symbol A2403 containing information on the number of optical modulation signals being transmitted' in some of the optical modulation signals from A2003_1 to A2003_16", the same effects as described above can be obtained.

[0620] Furthermore, another example will be described.

[0621] FIG. 55 shows an example of the frame configuration of the optical modulation signal transmitted by the transmission device 100 in FIGS. 53 and 54, and since it has already been described, the description will be omitted.

[0622] For example, the preamble and the configuration of the control information symbols in the frame configuration A2201_1 in the optical modulation signal A2003_1 in FIG. 55 are shown in FIG. 58, and the preamble and the configuration of the control information symbols from "the frame configuration A2201_2 in the optical modulation signal A2003_2" to "the frame configuration A2201_16 in the optical modulation signal A2003_16" are shown in FIG. 62. In FIG. 62, those that operate in the same manner as FIGS. 57 and 58 are given the same numbers, and the characteristic point of FIG. 62 is that it does not include "symbol A2403 including information on the number of optical modulation signals being transmitted". That is, the transmitting device 100 transmits "symbol A2403 including information on the number of optical modulation signals being transmitted" only in the optical modulation signal A2003_1.

[0623] At this time, in the case of the reception state in the receiving device 150 in FIG. 56, since the receiving device 150 does not obtain "symbol A2403 including information on the number of optical modulation signals being transmitted", it cannot grasp the number of optical modulation signals transmitted by the transmitting device 100. Then, the receiving device 150 determines that it is difficult to correctly receive the data, stops the signal processing of the reception operation, and can suppress unnecessary power consumption.

[0624] Note that in the description of this example, it is described that "the transmitting device 100 transmits'symbol A2403 including information on the number of optical modulation signals being transmitted' only in the optical modulation signal A2003_1", but this is not limited to this example. As long as "the transmitting device 100 transmits'symbol A2403 including information on the number of optical modulation signals being transmitted' in some of the optical modulation signals from A2003_1 to A2003_16", the same effects as described above can be obtained.

[0625] As yet another example, "the transmitting device 100 may be configured to transmit a preamble and control information symbols in some of the optical modulation signals from A2003_1 to A2003_16."

[0626] As described above, when the transmission device transmits a plurality of optical modulation signals, as described in this embodiment, by transmitting the optical modulation signals, the receiving device can obtain high data reception quality or can reduce power consumption.

[0627] In this embodiment, although the number of optical modulation signals transmitted by the transmission device is described as 16, it is not limited to this. For example, when the transmission device has a configuration such as 100 in FIG. 53, the number of optical modulation signals to be transmitted may be changed according to the transmission time. For example, in the first time, 16 optical modulation signals may be transmitted, in the second time, 8 optical modulation signals may be transmitted, and in the third time, 1 optical modulation signal may be transmitted. Also, in the case of this example, in the first time, the information "16" is transmitted in the "symbol A2404 including information on the number of optical modulation signals being transmitted", in the second time, the information "8" is transmitted in the "symbol A2404 including information on the number of optical modulation signals being transmitted", and in the third time, the information "1" is transmitted in the "symbol A2404 including information on the number of optical modulation signals being transmitted".

[0628] In this embodiment, the frame configuration in FIG. 55 is described as an example, but 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 FIG. 55.

[0629] Furthermore, the configurations of the preamble and control information symbols are described with respect to FIGS. 57, 58, 61, and 62. However, in each figure, there may be cases where some symbols do not exist, or there may be configurations where other symbols exist in each figure, and the operation can still be performed in the same manner. That is, the configurations of the preamble and control information symbols are not limited to the configurations in FIGS. 57, 58, 61, and 62. Also, the order in which the symbols constituting the preamble and control information symbols are transmitted is not limited to the examples in FIGS. 57, 58, 61, and 62.

[0630] (Embodiment 11) In this embodiment, for example, an implementation method for improving the reception quality of data of the receiving device 150 will be described in a situation where the reception state of the receiving device 150 is as shown in FIG. 56.

[0631] As described in Embodiment 10, when the receiving device 150 is in a situation as shown in FIG. 56, for example, it is difficult for the receiving device 150 to obtain correctly received data. Also, the reception state of the receiving device 150 may be as shown in FIG. 63. In FIG. 63, those that operate in the same manner as in FIG. 56 are given the same numbers.

[0632] In the case of FIG. 63, since the area irradiated by each light source in the light receiving part such as an image sensor is small, there is a problem that the reception quality of data in the receiving device 150 deteriorates. Also, when line scan method or line scan sampling for each region is performed, the reception quality of data in the receiving device 150 may be significantly deteriorated.

[0633] In this embodiment, a configuration example of the receiving device 150 that overcomes this problem will be described.

[0634] As a configuration example of a transmitting device that transmits data, there is the transmitting device 100 in FIG. 53. Since FIG. 53 has already been described, the description will be omitted.

[0635] The configuration of the receiving device 150 that receives the optical modulation signal transmitted by the transmitting device 100 in FIG. 53 is shown in FIG. 64.

[0636] Also, as a configuration example different from FIG. 53 of a transmitting device that transmits data, there is the transmitting device 100 in FIG. 54. Since FIG. 54 has already been described, the description will be omitted.

[0637] The configuration of the receiving device 150 that receives the optical modulation signal transmitted by the transmitting device 100 in FIG. 54 is shown in FIG. 65.

[0638] Hereinafter, the receiving apparatus 150 in FIGS. 64 and 65 will be described.

[0639] FIG. 64 is an example of the configuration of the receiving apparatus 150 that receives the optical modulation signal transmitted by the transmitting apparatus 100 in FIG. 53. For those that operate in the same manner as in FIG. 53, the same reference numerals are used.

[0640] The lens (group) A3101 takes the lens control signal A3109 as an input and performs controls such as focal length, aperture, and focus.

[0641] The image sensor (light receiving unit) A3103 takes the light A3102 after passing through the lens as an input and outputs the optical reception signals A2052_1 to A2502_M and the image signal A3104. Note that the image signal A3104 may be subjected to signal processing and then displayed as an image on the internal display unit, or may be displayed as an image on an external display unit via an interface.

[0642] The data acquisition unit A2055 takes the received data A2054_1 to A2054_M as inputs and outputs the data A2056 and the reception state information A3107.

[0643] The reception state information A3107 may be, for example, the "information regarding the number of optical modulation signals being transmitted" obtained from the "symbol A2403 including information regarding the number of optical modulation signals being transmitted" transmitted by the transmitting apparatus 100 in Embodiment 10, or the "information regarding the number of the optical modulation signal" obtained from the "symbol A2501 including information regarding the number of the optical modulation signal" transmitted by the transmitting apparatus 100. Also, the reception state information A3107 may be the reception state information generated from the "information regarding the number of optical modulation signals being transmitted" and the "information regarding the number of the optical modulation signal". Note that this is not limited to this example.

[0644] The object recognition unit A3105 takes the image signal A3104, the reception status information A3107, and the instruction signal A3150 as inputs, and performs object recognition based on the instruction signal A3150. For example, when the instruction signal A3150 indicates "perform communication", the object recognition unit A3105 will start recognizing the optical modulation signal. At this time, the object recognition unit A3105 takes the image signal A3104 and the reception status information A3107 as inputs and outputs the object recognition signal A3106. Specific operations will be described later.

[0645] The lens control unit A3108 takes the object recognition signal A3106 as an input, and for example, recognizes reception statuses such as those in FIGS. 56 and 63, and "determines whether to perform lens control, and if performing lens control, determines the set value of the focal length, the set value of the aperture, and the focus setting", and outputs the lens control signal A3109 corresponding to these controls. In FIG. 64, the lens control unit A3108 takes the object recognition signal A3106 as an input, but other input signals may also exist.

[0646] FIG. 65 is an example of the configuration of the receiving device 150 that receives the optical modulation signal transmitted by the transmitting device 100 in FIG. 54. Those that operate in the same manner as FIGS. 53 and 54 are given the same numbers. Note that the operations of the lens (group) A3101, the image sensor A3103, the object recognition unit A3105, and the lens control unit A3108 have already been described, so the description is omitted here.

[0647] The error correction decoding unit A2155 takes the received data A2054_1 to A2054_M as inputs and outputs the data A2056 and the reception status information A3107.

[0648] Next, a specific example will be described regarding the control method of the lens (group) A3101 in FIGS. 64 and 65.

[0649] As described in Embodiment 10, for example, when the reception state of the receiving device 150 is as shown in FIG. 56, since the light receiving unit is not receiving the light irradiated by some light sources, it is difficult for the receiving device 150 to correctly receive data. Also, as already described, when the reception state of the receiving device 150 is as shown in FIG. 63, there is a problem that the reception quality of the data of the receiving device 150 is poor.

[0650] On the other hand, when the receiving device 150 is in a reception state as shown in FIGS. 59 and 60, the reception quality of the data is high.

[0651] From the above, when the receiving device 150 controls the lens (group) A3101 so as to be in a reception state as shown in FIGS. 59 and 60, the reception quality of the data is improved. The receiving devices 150 in FIGS. 64 and 65 are examples of configurations for realizing this.

[0652] A specific example of the control of the receiving device 150 in FIGS. 64 and 65 will be described.

[0653] Assume that the reception state of the receiving device 150 is in a state as shown in FIG. 56, for example. At this time, since the reception state information A3107 in FIGS. 64 and 65 is information created based on "information regarding the number of optical modulation signals being transmitted" and "information regarding the numbers of the optical modulation signals" as already described, the object recognition unit A3105 in FIGS. 64 and 65 recognizes that 3 out of 16 optical modulation signals are being received.

[0654] Furthermore, the object recognition unit A3105 will recognize from the image signal A3104 "the reception state of the light modulation signal, for example, at which positions of the image sensor the three light modulation signals are received". That is, the object recognition unit A3105 will perform object recognition on the image of FIG. 56. Then, the object recognition unit A3105 recognizes "the reception state of the light modulation signal" and "the fact that 16 light modulation signals cannot be received". Further, in the case of this example, the object recognition unit A3105 determines to perform lens control based on these recognition results, and "determines the set value of the suitable focal length, the set value of the suitable aperture, and the setting of the suitable focus" for realizing suitable communication, and outputs an object recognition signal A3106 including this information. Note that the object recognition signal A3106 only needs to include at least "the set value of the suitable focal length", and the object recognition signal A3106 does not necessarily need to include the information of the set value of the suitable aperture and the setting of the suitable focus.

[0655] The lens control unit A3108 takes the object recognition signal A3106 as an input, and outputs a lens control signal A3109 for controlling the lens (group) A3101 based on the information such as "the set value of the suitable focal length, the set value of the suitable aperture, and the setting of the suitable focus" included in the object recognition signal A3106.

[0656] By implementing such a series of operations, the receiving device 150 in FIGS. 64 and 65 enters a reception state as shown in FIGS. 59 and 60, for example, and thus the effect that high-quality data reception can be obtained is achieved.

[0657] In the above example, the case where the reception state of the receiving device 150 is controlled from FIG. 56 to "FIGS. 59 and 60" is described as an example, but this is not limited to this example, and the reception state of the receiving device 150 may be controlled from FIG. 63 to "FIGS. 59 and 60". However, it is not limited to this.

[0658] Next, an example of controlling the receiving device 150 in FIGS. 66 and 67, which is different from FIGS. 64 and 65, will be described.

[0659] FIG. 66 is an example of the configuration of a receiving device 150 that receives the optical modulation signal transmitted by the transmitting device 100 in FIG. 53. For those that operate in the same manner as in FIG. 64, the same reference numerals are assigned, and the description of the parts that have already been explained is omitted.

[0660] The difference between the receiving device 150 in FIG. 66 and the receiving device 150 in FIG. 64 is that there is a signal processing unit A3302 after the image sensor A3103.

[0661] It is assumed that the signal processing unit A3302 has at least a zoom (image enlargement (·reduction)) processing function.

[0662] Therefore, the signal processing unit A3302 takes the image signal A3301, the zoom signal A3300, the object recognition signal A3106, and the instruction signal A3150 as inputs. When the instruction signal A3150 indicates that it is in the "shooting mode (performing shooting)", 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 image signal A3104 after signal processing.

[0663] When the instruction signal A3150 indicates that it is in the "communication mode (performing communication)", the signal processing unit A3302 performs zoom signal processing on the image signal A3301 based on the information such as "the set value of the suitable focal length, the set value of the suitable aperture, and the setting of the suitable focus" included in the object recognition signal A3106, and outputs the image signal A3104 after signal processing and the optical reception signals 2052_1 to A2052_M after signal processing. As a result, as described above, since the reception state is improved, the effect of improving the reception quality of data can be obtained.

[0664] Note that since the method of improving the reception state in the lens control unit A3108 has already been described, the description is omitted.

[0665] By doing as described above, since the reception state of the receiving device 150 is improved, the effect that the reception quality of data is improved can be obtained. In FIG. 66, when the lens (group) A3101 does not have a focal length changing function, the change of the focal length for reception improvement will not be performed.

[0666] FIG. 67 is an example of the configuration of the receiving device 150 that receives the optical modulation signal transmitted by the transmitting device 100 in FIG. 54. For those that operate in the same manner as in FIG. 65, the same reference numerals are given, and the description of the parts that have already been explained is omitted.

[0667] The difference between the receiving device 150 in FIG. 67 and the receiving device 150 in FIG. 65 is that, similar to FIG. 66, a signal processing unit A3302 exists after the image sensor A3103.

[0668] Note that since the details of the operation of the signal processing unit A3302 have already been described, the description is omitted. Also, as described in this already given explanation, since the reception state is improved, the effect that the reception quality of data is improved can be obtained.

[0669] Note that since the method for improving the reception state in the lens control unit A3108 has already been described, the description is omitted.

[0670] By doing as described above, since the reception state of the receiving device 150 is improved, the effect that the reception quality of data is improved can be obtained. In FIG. 67, when the lens (group) A3101 does not have a focal length changing function, the change of the focal length for reception improvement will not be performed.

[0671] Incidentally, in the receiving device 150 of FIGS. 64, 65, 66, and 67, assume that the lens (group) A3101 can be set to a plurality of values as the focal length. For example, a method such as being able to set the focal length to be 12 mm or more and 35 mm or less, or being able to set the focal lengths to be 12 mm and 25 mm is conceivable. The following will be described based on this example.

[0672] As a first example, consider the case where a plurality of discrete values are supported as the focal length.

[0673] When the receiving device 150 in FIGS. 64, 65, 66, and 67 is set to the "communication mode" by the instruction signal A3150, communication will start. At this time, the focal length of the lens (group) A3101 may be set to, for example, 12 mm, which is the widest angle. This is because when set to the widest angle, it is highly likely to avoid the reception state where it is difficult to receive some optical modulations as shown in FIG. 56. As a result, the effect of improving the reception quality of data can be obtained. However, in order to further improve the reception quality of data, the focal length and the like may be controlled to suitable values.

[0674] In this example, the case where 12 mm and 25 mm are supported as the focal length is described as an example. However, even if two or more types of focal lengths are supported, setting to the focal length of the widest angle at the start of communication, for example, is an effective method in terms of improving the reception quality of data.

[0675] As a second example, consider the case where the focal length can be set continuously (or finely).

[0676] When the receiving device 150 in FIGS. 64, 65, 66, and 67 is set to the "communication mode" by the instruction signal A3150, communication will start. At this time, the focal length of the lens (group) A3101 may be set to, for example, 12 mm, which is the widest angle. This is because when set to the widest angle, it is highly likely to avoid the reception state where it is difficult to receive some optical modulations as shown in FIG. 56. As a result, the effect of improving the reception quality of data can be obtained. However, in the case of this example, since the focal length can be set finely, for example, even if it is set to 14 mm, it is highly likely to obtain an equivalent effect. However, in order to further improve the reception quality of data, the focal length and the like may be controlled to suitable values.

[0677] In the receiving device 150 shown in FIGS. 66 and 67, consider the case where the signal processing unit A3302 has a zoom (image enlargement (· reduction)) processing function. At this time, an example will be described for the cases corresponding to 1x image enlargement (no enlargement), 2x image enlargement, and 4x image enlargement.

[0678] When the receiving device 150 shown in FIGS. 66 and 67 is set to the "communication mode" by the instruction signal A3150, communication will start. At this time, as the zoom (image enlargement (· reduction)) of the signal processing unit A3302, it is preferable to set it to "1x image enlargement (no enlargement)", which is the widest angle. This is because when set to the widest angle, as shown in FIG. 56, it is highly likely to avoid the reception state where it is difficult to receive some light modulation. As a result, the effect of being able to improve the reception quality of data can be obtained. However, in order to further improve the reception quality of data, the zoom value may be controlled to a suitable value.

[0679] (Supplementary Note 1) Naturally, it is also possible to implement by combining a plurality of the embodiments and other contents described in this specification.

[0680] Also, each embodiment is merely an example. For example, even if "modulation method, error correction coding method (error correction code used, code length, coding rate, etc.), control information, etc." are exemplified, it is possible to implement with the same configuration even when applying other "modulation method, error correction coding method (error correction code used, code length, coding rate, etc.), control information, etc.".

[0681] 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, 256QAM, 1024QAM, 4096QAM, etc.) may be applied, and in each modulation method, uniform mapping or non-uniform mapping may be used. Also, the arrangement method of signal points such as 2, 4, 8, 16, 64, 128, 256, 1024, etc. in the I-Q plane (modulation methods having 2, 4, 8, 16, 64, 128, 256, 1024, etc. signal points) is not limited to the signal point arrangement method of the modulation methods shown in this specification.

[0682] Devices equipped with the wireless device described in this specification may be, for example, communication and broadcasting devices such as broadcasting stations, base stations, access points, terminals, mobile phones, etc., and communication devices such as TVs, radios, terminals, personal computers, mobile phones, access points, base stations, etc. Also, the wireless device described in this specification is a device having a communication function, and it is also conceivable that the device can be connected by disassembling some interface to a device for executing applications such as TVs, radios, personal computers, mobile phones, etc.

[0683] Also, those equipped with the receiving unit described in this specification can be, for example, communication and broadcasting devices such as broadcasting stations, base stations, access points, terminals, mobile phones, etc., and communication devices such as TVs, radios, terminals, personal computers, mobile phones, access points, base stations, etc.

[0684] In the wireless communication by radio waves in this embodiment, symbols other than data symbols, for example, pilot symbols (preamble, unique word, postamble, reference symbols, etc.), symbols for control information, etc. can be arranged in the frame in any manner. And here, although they are named pilot symbols and symbols for control information, any naming method can be used, and the roles of each symbol are important.

[0685] The pilot symbol can be, for example, a known symbol modulated using PSK modulation in a transceiver (or the receiver may be able to know the symbol transmitted by the transmitter by synchronizing. ). The receiver will use this symbol to perform frequency synchronization, time synchronization, channel estimation (estimation of CSI (Channel State Information) of each modulation signal), signal detection, etc.

[0686] Also, the symbol for control information is a symbol for transmitting information (for example, modulation method, error correction coding method, coding rate of error correction coding method, setting information at the upper layer, etc.) that needs to be transmitted to the communication partner to realize communication other than data (such as applications).

[0687] (Supplementary Note 2) The moving image encoding method described in each of the above embodiments can use a method compliant with specifications defined under names such as, for example, MPEG (Moving Picture Experts Group) 2, H.264 / AVC (Advanced Video Coding), H.265 / HEVC (High Efficiency Video Coding), VC-1, VP8, VP9. However, the moving image encoding method described in each of the above embodiments may use a moving image encoding method different from the methods listed above.

[0688] Note that the present disclosure is not limited to each embodiment, and various modifications can be made and implemented. For example, in each embodiment, the case of performing as a communication device is described, but it is not limited thereto, and this communication method can be realized by software, hardware, or software in cooperation with hardware.

[0689] Note that, for example, a program for executing the above communication method, transmission method, or reception method may be stored in a ROM (Read Only Memory) in advance, and the program may be operated by a CPU (Central Processor Unit).

[0690] Also, a program for executing the above communication method, transmission method, or reception method may be stored in a computer-readable storage medium, the program stored in the storage medium may be recorded in a RAM (Random Access Memory) of the computer, and the computer may be operated according to the program.

[0691] Moreover, each functional block used in the description of each of the above embodiments may be partially or wholly realized as an LSI (Large Scale Integration), which is an integrated circuit, and each process described in each of the above embodiments may be controlled partially or wholly by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip so as to include some or all of the functional blocks. The LSI may be provided with data input and output. Depending on the degree of integration, the LSI may also be referred to as an IC (Integrated Circuit), a system LSI, a super LSI, or an ultra LSI. The method of integrating into an integrated circuit is not limited to LSI, and it may also be realized by an application-specific circuit, a general-purpose processor, or an application-specific processor. Further, after manufacturing the LSI, an FPGA (Field Programmable Gate Array) that can be programmed or a reconfigurable processor capable of reconfiguring the connection and setting of circuit cells inside the LSI may be used. The present disclosure may be realized as digital processing or analog processing. Furthermore, if an integrated circuit technology that replaces LSI appears due to the advancement of semiconductor technology or other derived technologies, of course, the technology may be used to integrate the functional blocks. The application of biotechnology or the like is possible as a possibility.

[0692] (Supplementary Note 3) Note that at least one of an FPGA (Field Programmable Gate Array) and a CPU (Central Processing Unit) may be configured such that all or part of the software necessary to implement the communication method, transmission method, or reception method described in the present disclosure can be downloaded by wireless communication or wired communication. Further, it may be configured such that all or part of the software for updating can be downloaded by wireless communication or wired communication. Then, the downloaded software is stored in the storage unit, and at least one of the FPGA and the CPU is operated based on the stored software, so that the digital signal processing described in the present disclosure may be executed.

[0693] At this time, a device including at least one of an FPGA and a CPU may be connected wirelessly or wired to a communication modem, and the communication method, transmission method, or reception method described in the present disclosure may be realized by this device and the communication modem.

[0694] For example, a communication device (transmission device or reception device) such as a base station, an AP, or a terminal described in this specification includes at least one of an FPGA and a CPU, and the communication device may include an interface for obtaining software from the outside for operating at least one of the FPGA and the CPU. Further, the communication device may include a storage unit for storing software obtained from the outside, and may realize the signal processing described in the present disclosure by operating the FPGA and the CPU based on the stored software.

[0695] The first "vehicle" may include the transmission device described in this specification, the second "vehicle" may include the reception device described in this specification, and data transmission and reception may be performed.

[0696] The "transmission device or a part of the function of the transmission device" described in this specification may be connected to the first "vehicle" via an interface, and the "reception device or a part of the reception device" described in this specification may be connected to the second "vehicle" via an interface, and data transmission by transmission and reception may be performed.

[0697] Also, the first "vehicle" may include the transmission device described in this specification, and data transmission and reception may be performed between this transmission device and the reception device described in this specification.

[0698] The second "vehicle" may include the reception device described in this specification, and data transmission and reception may be performed between this reception device and the transmission device described in this specification.

[0699] Furthermore, the "transmission device, or a part of the functions of the transmission device" described in this specification may be connected to a first "vehicle, or a conveyance" via an interface, and data transmission and reception may be performed between this series of transmission devices and the reception device described in this specification.

[0700] The "reception device, or a part of the reception device" described in this specification may be connected to a second "vehicle, or a conveyance" via an interface, and data transmission and reception may be performed between the transmission device described in this specification and this series of reception devices.

[0701] If the "vehicle, or a conveyance" includes the transmission device described in this specification, or a part of the transmission device, or if the "vehicle, or a conveyance" is connected via an interface to the "transmission device described in this specification" or the "functions of a part of the transmission device described in this specification", the light source included in the "vehicle, or a conveyance" may be used as the light source included in the transmission device described in this specification.

[0702] For example, as shown in FIG. 68, vehicle B100 includes light sources B101_1, B101_2, B101_3, and B101_4, and one or more of these light sources may be used as the light source for the transmission device described in this specification to transmit a light modulation signal.

[0703] In addition, among the plurality of light sources mounted on vehicle B100, the transmission device, or a device connected to the transmission device, may have a function of selecting "which light source to use as the light source for the transmission device described in this specification to transmit a light modulation signal". Also, the brightness, irradiation angle, and position of the light source may be set together.

[0704] "The ""vehicle or conveyance"" is equipped with the receiving device described in this specification, or a part of the receiving device", or "when the ""vehicle or conveyance"" is connected via an interface to the ""receiving device described in this specification"" or the ""function of a part of the receiving device described in this specification"", as the light receiving unit included in the receiving device described in this specification, a light receiving unit (e.g., an image sensor, a photodiode, etc.) included in the ""vehicle or conveyance"" may be used."

[0705] For example, as shown in FIG. 69, vehicle B100 is equipped with light receiving units B201_1, B201_2, B201_3, B201_4, B201_5, B201_6, and one or more of these light receiving units may be used as the light receiving unit for the receiving device described in this specification to receive the optical modulation signal.

[0706] In addition, among the plurality of light receiving units mounted on vehicle B100, the receiving device or a device connected to the receiving device may be equipped with a function of selecting ""which light receiving unit to use as the light receiving unit for the receiving device described in this specification to receive the optical modulation signal"". Also, the angle of the light receiving unit and the position of the light receiving unit may be set together.

[0707] Furthermore, the fact that the receiving device described in this specification can receive data may be displayed on the front panel mounted on the vehicle or the cockpit mounted on the conveyance. Also, the fact that the receiving device described in this specification can receive data may be notified to the user by vibrating the steering wheel of the vehicle or the like itself or the vibrator included in the steering wheel.

[0708] (Supplementary Note 4) In this specification, the server may provide an application related to the processing associated with the receiving device, and the terminal may implement 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 a communication device including the transmitting device described in this specification connecting to the server via a network, or the application may be provided to the terminal by a communication device having another transmission function connecting to the server via a network.

[0709] Similarly, in this specification, the server may provide an application related to the processing associated with the transmitting device, and the communication device may implement the functions of the transmitting device described in this specification by installing this application. Note that a method is conceivable in which the application is provided to this communication device by another communication device connecting to the server via a network.

[0710] Further, the server may provide software related to the light source included in the transmitting device and the light receiving unit included in the receiving device, and by obtaining this software, the light source included in the transmitting device can correspond to the transmission of an optical modulation signal, and the light receiving unit included in the receiving device can correspond to the reception of an optical modulation signal.

[0711] Furthermore, the transmitting device in this specification may have the functions of a server, provide the application included in the transmitting device to the communication device using some communication means, and the communication device may be able to implement the receiving device in this specification by the application obtained by downloading.

[0712] Note that in this specification, although "lighting unit" and "light source" are described, a method may be adopted in which a display or a projector that displays an image, a video, an advertisement, etc. emits light and an optical modulation signal is included in the light. That is, the "lighting unit" and "light source" may have functions other than the function of emitting light. Also, the "lighting unit" and "light source" may be composed of a plurality of "lighting" and "light source".

[0713] Furthermore, the transmission method used by a communication device that generates an optical modulation signal and emits light may be a method other than the transmission methods described in this specification. Also, the optical modulation signal may include information other than that described in this specification.

[0714] Also, lighting sources such as LEDs themselves may have the functions of the transmission devices described in this specification.

[0715] Furthermore, although the case where the transmission device and the reception device described in this specification are mounted on a vehicle is described as an example, it is not limited to this. The transmission device and the reception device may be mounted on other objects, or even if the transmission device and the reception device exist alone, they can perform the operations described in this specification and obtain similar effects.

[0716] (Supplementary Note 5) The communication device and the reception device in the present disclosure may be in any of the aspects of Embodiments 1 to 11.

[0717] That is, a first communication device, which is 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 the 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...

Claims

**Claim 1** 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 signal, and stores the demodulated data in a memory in association with the detected object. A receiving device. **Claim 2** The demodulated data includes connection information for connecting to the object by wireless communication. The receiving device according to claim 1. **Claim 3** The relationship between the object and the demodulated data is determined based on the position of the object in the image data. The receiving device according to claim 1. **Claim 4** A receiving method performed by a receiving device including one or more image sensors, wherein the one or more image sensors acquire image data and received signals, an object is detected by performing image processing on the image data, demodulated data is acquired by demodulating the received signal, and the demodulated data is stored in a memory in association with the detected object. A receiving method. **Claim 5** The demodulated data includes connection information for connecting to the object by wireless communication. The receiving method according to claim 4. **Claim 6** The relationship between the object and the demodulated data is determined based on the position of the object in the image data. The receiving method according to claim 4.

Images