Optical communication device, optical communication method, and optical communication program

Abstract

This optical communication device comprises: a light-emitting element; a body unit that has a spherical or rod-form shape; a plurality of light-receiving elements that are arranged on the surface of the body unit with a prescribed spacing therebetween; a movement mechanism that movably supports the light-receiving elements above the surface of the body unit; and a control unit that, on the basis of the reception state of optical signals that are received by the plurality of light-receiving elements from another optical communication device, controls the movement mechanism so as to move the light-emitting element to a position facing the other optical communication device.

Description

[Technical Field]

[0001] The present disclosure relates to an optical communication device, an optical communication method, and an optical communication program. [Background technology]

[0002] For example, in underwater communications, optical communication systems that use visible light (hereinafter simply referred to as "light") as a transmission medium are known. Because light has high directionality, conventional optical communication systems generally communicate by placing the transmitting and receiving sides facing each other, with the optical communication devices on each side fixed.

[0003] Patent Documents 1 and 2 describe optical communication devices that rotatably support a housing that houses a pair of a light-emitting element and a light-receiving element whose optical axes are oriented in the same direction, and that rotate the housing in various directions. In such optical communication devices, by rotating the housing, the light-receiving element detects an optical signal from another optical communication device with which to communicate, and directs the optical axes of the light-emitting element and the light-receiving element toward the other optical communication device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6725835 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-28756 Summary of the Invention

[0005] The optical communication device of the first aspect comprises a light-emitting element, a main body having a spherical or rod-like shape, a plurality of light-receiving elements arranged at a predetermined interval on the surface of the main body, a moving mechanism that supports the light-emitting element movably above the surface, and a control unit that controls the moving mechanism to move the light-emitting element to a position facing another optical communication device based on the reception status of optical signals received by the plurality of light-receiving elements from the other optical communication device.

[0006] The optical communication method according to the second aspect is an optical communication method performed by an optical communication device, and includes the steps of receiving an optical signal from another optical communication device using a plurality of light-receiving elements arranged at a predetermined interval on the surface of a main body having a spherical or rod-shaped shape, and controlling, based on the reception status of the optical signal, to move the light-emitting element to a position facing the other optical communication device using a moving mechanism that movably supports the light-emitting element above the surface.

[0007] The optical communication program according to the third aspect causes an optical communication device to execute the steps of receiving an optical signal from another optical communication device using a plurality of light receiving elements arranged at predetermined intervals on the surface of a main body having a spherical or rod-like shape, and controlling the movement of the light emitting element to a position facing the other optical communication device using a moving mechanism that movably supports the light emitting element above the surface based on the reception status of the optical signal. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a configuration of an optical communication system according to an embodiment. [Figure 2] 1 is a diagram illustrating an external configuration of an optical communication device according to an embodiment. [Figure 3] 2 is a diagram showing the external appearance of the optical communication device according to the embodiment as viewed from above (direction "A" in FIG. 2). [Figure 4] 2 is a diagram showing the appearance of the optical communication device according to the embodiment as viewed from the side (direction "B" in FIG. 2). [Figure 5] 1 is a diagram illustrating a block configuration of an optical communication device according to an embodiment. [Figure 6] 5A and 5B are diagrams for explaining movement control of light-emitting elements and control of light-receiving elements according to an embodiment. [Figure 7] 4A and 4B are diagrams for explaining a first specific example of movement control of a light-emitting element according to the embodiment. [Figure 8] 10A and 10B are diagrams for explaining a second specific example of movement control of a light-emitting element according to the embodiment. [Figure 9]10A and 10B are diagrams for explaining a third specific example of movement control of a light-emitting element according to the embodiment. [Figure 10] 10A and 10B are diagrams for explaining a situation in which optical communication according to an embodiment is interrupted; [Figure 11] 10A and 10B are diagrams for explaining a recovery operation when optical communication is interrupted according to an embodiment. [Figure 12] FIG. 4 is a diagram illustrating an operation flow of the optical communication device according to the embodiment. [Figure 13] FIG. 10 is a diagram illustrating an operation flow when optical communication of the optical communication device according to the embodiment is interrupted. [Figure 14] FIG. 10 is a diagram for explaining a first modified example of the optical communication device according to the embodiment. [Figure 15] FIG. 10 is a diagram for explaining a second modified example of the optical communication device according to the embodiment. [Figure 16] FIG. 10 is a diagram for explaining a third modified example of the optical communication device according to the embodiment. [Figure 17] FIG. 10 is a diagram for explaining a fourth modified example of the optical communication device according to the embodiment. [Figure 18] FIG. 10 is a diagram for explaining a fourth modified example of the optical communication device according to the embodiment. [Figure 19] FIG. 10 is a diagram for explaining a fourth modified example of the optical communication device according to the embodiment. [Figure 20] FIG. 10 is a diagram for explaining a fifth modified example of the optical communication device according to the embodiment. [Figure 21] FIG. 10 is a diagram for explaining a fifth modified example of the optical communication device according to the embodiment. [Figure 22] FIG. 10 is a diagram for explaining a fifth modified example of the optical communication device according to the embodiment. [Figure 23] FIG. 10 is a diagram for explaining another embodiment. [Figure 24] FIG. 10 is a diagram for explaining another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The conventional method of changing the direction of the light-emitting element and the light-receiving element as a single unit leaves room for improvement in terms of efficient optical communication. For example, with the conventional method, if an optical communication device does not know the approximate direction of another optical communication device with which it is communicating when starting communication, there is a concern that it will take a long time for the light-receiving element to detect the optical signal from the other optical communication device. Furthermore, with the conventional method, it is difficult to handle scenarios such as handover of optical communication devices.

[0010] Therefore, an object of the present disclosure is to enable efficient optical communication.

[0011] An optical communication system and an optical communication device according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0012] (1) Optical communication system configuration First, the configuration of an optical communication system according to an embodiment will be described. Fig. 1 is a diagram showing the configuration of an optical communication system according to an embodiment.

[0013] The optical communication system according to the embodiment is a system that performs underwater optical communication between optical communication devices 1. That is, each optical communication device 1 is an underwater optical communication device. In the embodiment, underwater optical communication is mainly assumed to be undersea optical communication, but underwater optical communication may also be optical communication in a lake or river. The optical communication system according to the embodiment is not limited to underwater optical communication, and may also be applied to optical communication on land (or in space).

[0014] The example in Figure 1 shows an operation of transmitting an optical signal from one optical communication device 1 (1a) to another optical communication device 1 (1b). The one optical communication device 1 (1a) transmits an optical signal with its optical axis directed toward the other optical communication device 1 (1b). Similarly, the other optical communication device 1 (1b) transmits an optical signal with its optical axis directed toward the one optical communication device 1 (1a). Here, it is assumed that the one optical communication device 1 (1a) is a terminal device, and the other optical communication device 1 (1b) is a base station device.

[0015] In the example of FIG. 1, base station device 1b is located near the water surface. For example, base station device 1b may be fixed to a buoy. Base station device 1b may be connected to a network via a backhaul line. The backhaul line may be a wireless line and / or a wired line. In order to efficiently secure a communication area underwater, base station device 1b may be installed a predetermined distance away from other adjacent base station devices. Base station device 1b may be installed temporarily, for example, for the period during which underwater surveys are conducted using terminal device 1a.

[0016] The terminal device 1a may be configured to be able to move underwater. The terminal device 1a performs optical communication (specifically, underwater optical communication) with the base station device 1b. That is, the base station device 1b is a serving base station for each terminal device 1a. The terminal device 1a may include a sensor such as an image sensor (including a camera) and generate sensor data. For example, the terminal device 1a may transmit uplink data including the sensor data to the base station device 1b by optical communication. The terminal device 1a may receive downlink (DL) data including instruction data from the base station device 1b by optical communication. The terminal device 1a may move and perform a sensing operation (such as taking a photograph) based on the instruction data.

[0017] (2) Optical communication device configuration Next, the configuration of the optical communication device 1 according to the embodiment will be described.

[0018] (2.1) External configuration of optical communication equipment FIG. 2 is a diagram showing the external configuration of the optical communication device 1 according to the embodiment.

[0019] The optical communication device 1 according to the embodiment includes a light-emitting element 10, a spherical body 20, a plurality of light-receiving elements 30 arranged at predetermined intervals on the surface of the body 20, and a movement mechanism 40 that movably supports the light-emitting element 10 above the surface of the body 20. By arranging the plurality of light-receiving elements 30 at predetermined intervals on the surface of the spherical body 20, it is possible to simultaneously receive optical signals arriving from various directions. This makes it possible to efficiently detect a communication partner in an unknown direction. Furthermore, the movement mechanism 40 allows the optical axis of the light-emitting element 10 to be directed in various directions. This allows the number of light-emitting elements 10 to be limited to one, thereby reducing power consumption, heat generation, and interference with other optical communication devices.

[0020] The multiple light receiving elements 30 are distributed over the entire surface of the main body 20. As will be described in detail later, the multiple light receiving elements 30 are arranged in the vertical and horizontal directions in a two-dimensional array. The optical axis of each light receiving element 30 is oriented in the normal direction to the surface (i.e., the curved surface) of the main body 20.

[0021] In the embodiment, the optical communication device 1 has a spherical housing 50 that houses the light emitting element 10, the main body 20, a plurality of light receiving elements 30, and the movement mechanism 40. The housing 50 is formed of a light-transmitting member (e.g., transparent resin). This enables optical communication using the light emitting element 10 and the light receiving elements 30, while preventing water from entering the inside even when the optical communication device 1 is underwater.

[0022] In the embodiment, the movement mechanism 40 has a first rotation shaft 41 provided on the main body 20, a first arm 42 rotatably supported by the first rotation shaft 41 and rotationally moving the light-emitting element 10 in a first direction (horizontal direction), a second rotation shaft 43 provided on the first arm 42, and a second arm 44 rotatably supported by the second rotation shaft 43 and rotationally moving the light-emitting element 10 in a second direction (vertical direction) perpendicular to the first direction. In this way, the movement mechanism 40 is configured with a two-axis gimbal mechanism, and the movement mechanism 40 can orient the optical axis of the light-emitting element 10 in all directions, so that the optical axis of the light-emitting element 10 can always face the communication partner.

[0023] Fig. 3 is a diagram showing the appearance of the optical communication device 1 as viewed from above (direction "A" in Fig. 2), and Fig. 4 is a diagram showing the appearance of the optical communication device 1 as viewed from the side (direction "B" in Fig. 2). However, in Figs. 3 and 4, the light receiving elements 30 and the housing 50 are not shown.

[0024] The first rotation shaft 41 is provided in the vertical direction on the main body 20. The first rotation shaft 41 is rotationally driven, for example, by an actuator provided on the main body 20. The first arm 42 is formed in an arc shape, and both ends of the first arm 42 are supported by the first rotation shaft 41. The first arm 42 is formed in an arc shape (semi-arc shape) with a central angle of 180°. Rotation of the first rotation shaft 41 rotates the first arm 42 in the horizontal direction, thereby allowing the light emitting element 10 and its optical axis to rotate 360° in the horizontal direction.

[0025] The second rotation shaft 43 is provided laterally on the first arm 42 at a vertically intermediate position of the first arm 42. The second rotation shaft 43 is rotationally driven, for example, by an actuator provided on the first arm 42. The second arm 44 is formed in an arc shape. One end of the second arm 44 is supported by the second rotation shaft 43. The light-emitting element 10 is provided on the other end of the second arm 44. The second arm 44 is formed in an arc shape with a central angle of 90°. The light-emitting element 10 is disposed on the second arm 44 so that its optical axis coincides with the normal direction of the spherical main body 20. Rotation of the second rotation shaft 43 rotates the second arm 44 vertically, thereby rotating the light-emitting element 10 and its optical axis by 180° vertically.

[0026] The movement mechanism 40 may be provided with wiring for transmitting an electric signal from the main body 20 to the light emitting element 10, and wiring for transmitting drive power to the actuator.

[0027] (2.2) Block diagram of optical communication equipment FIG. 5 is a block diagram showing the configuration of the optical communication device 1 according to the embodiment.

[0028] The optical communication device 1 has a light-emitting element 10, a plurality of light-receiving elements 30 (30a, 30b, ...) that form a light-receiving element group, a movement mechanism 40, and a control unit 110. The optical communication device 1 may have a battery for supplying power necessary for the operation of the optical communication device 1. The control unit 110 may be provided within the main body unit 20.

[0029] The light-emitting element 10 is controlled by the control unit 110 via the movement mechanism 40. The light-emitting element 10 may be a laser diode or a light-emitting diode. The light-emitting element 10 may include a drive circuit. The light-emitting element 10 converts an electrical signal (transmission signal) output from the control unit 110 via the movement mechanism 40 into an optical signal and transmits the optical signal.

[0030] Each light receiving element 30 receives an optical signal, converts the received optical signal into an electrical signal (received signal), and outputs the received signal to the control unit 110. Each light receiving element 30 may be a photodiode.

[0031] The movement mechanism 40 moves the light-emitting element 10 under the control of the control unit 110. The movement mechanism 40 has a movement mechanism 40a that moves the light-emitting element 10 in the horizontal direction and a movement mechanism 40b that moves the light-emitting element 10 in the vertical direction. The movement mechanism 40a includes a first rotation shaft 41 and a first arm 42. The movement mechanism 40b includes a second rotation shaft 43 and a second arm 44.

[0032] The control unit 110 controls the overall operation of the optical communication device 1. For example, the control unit 110 controls the light-emitting element 10, each light-receiving element 30, and the movement mechanism 40. The control unit 110 includes at least one processor 111 and at least one memory 112. The memory 112 stores programs executed by the processor 111 and information used in processing by the processor 111. The processor 111 may include a digital signal processor and a CPU. The digital signal processor performs modulation / demodulation, encoding / decoding, etc. of digital signals. The CPU executes programs stored in the memory 112 to perform various processes. As will be described in detail later, the memory 112 holds a movement position table that associates movement target positions (coordinates) of the light-emitting element 10 with the light-receiving elements 30.

[0033] The control unit 110 controls the movement mechanism 40 to move the light emitting element 10 to a position facing another optical communication device based on the reception status of optical signals received by the multiple light receiving elements 30 from the other optical communication device. Specifically, the control unit 110 detects the direction of the communication partner based on the reception intensity distribution of the optical signals received by the multiple light receiving elements 30, and sequentially moves the light emitting element 10 in the detected direction, thereby always causing the light emitting element 10 to face the communication partner. Details of such movement control of the light emitting element 10 will be described later.

[0034] In the embodiment, the optical signal (received signal) used for movement control of the light-emitting element 10 is a pilot signal including a known signal sequence. The pilot signal is also called a reference signal. The optical signal (received signal) used for movement control of the light-emitting element 10 may be a synchronization signal.

[0035] The optical communication device 1 may have a communication unit 140 that performs communication other than optical communication (for example, wired communication or acoustic wave communication). When the optical communication device 1 is a base station device, the communication unit 140 may be a backhaul communication unit that performs backhaul communication via a backhaul line. The communication unit 140 may receive a command that controls (or triggers) the movement of the moving mechanism 40 from an external device. In this case, the control unit 110 may control the movement of the moving mechanism 40 in response to the command.

[0036] (3) Operation of optical communication equipment Next, the operation of the optical communication device 1 according to the embodiment will be described.

[0037] (3.1) Control of light-emitting element movement and light-receiving element control 6 is a diagram for explaining the movement control of the light emitting element 10 according to the embodiment and the control of each light receiving element 30. In FIG. 6, a part of the main body 20 is shown enlarged.

[0038] The control unit 110 controls the movement mechanism 40 to move the light-emitting element 10 to a target position near the light-receiving element 30 where the received strength of the pilot signal is greatest. This allows the light-emitting element 10 to be moved to a position corresponding to the direction in which the communication partner is located, and makes it possible to orient the optical axis of the light-emitting element 10 in the direction in which the communication partner is located. In FIG. 6, the horizontal movement path of the light-emitting element 10 is indicated by "R1", and the vertical movement path of the light-emitting element 10 is indicated by "R2".

[0039] Here, the control unit 110 positions the light-emitting element 10 so that the light-emitting element 10 and the moving mechanism 40 (particularly the second arm 44) are not directly above each light-receiving element 30. This makes it possible to suppress a decrease in the receiving sensitivity of each light-receiving element 30. In the embodiment, the control unit 110 identifies the first light-receiving element 30 having the highest pilot signal receiving strength and the second light-receiving element 30 having the second lowest pilot signal receiving strength, and controls the moving mechanism 40 to move the light-emitting element 10 to a target position on or near a line connecting the first light-receiving element 30 and the second light-receiving element 30. This makes it possible to move the light-emitting element 10 to an appropriate position.

[0040] The control unit 110 may periodically control the moving mechanism 40 based on the reception strength of the pilot signal (i.e., control the movement of the light-emitting element 10). As will be described in detail later, the period for controlling the moving mechanism 40 based on the reception strength of the pilot signal may be variable. The control unit 110 may control the moving mechanism 40 based on the reception strength of the pilot signal using the reception of a command from an external device as a trigger.

[0041] Furthermore, when moving the light-emitting element 10, the control unit 110 controls the movement mechanism 40 so that the light-emitting element 10 does not pass directly above each light-receiving element 30. For example, when moving the light-emitting element 10, the control unit 110 controls the movement mechanism 40 so that the light-emitting element 10 moves vertically and horizontally in a time-division manner. In FIG. 6, the control unit 110 moves the light-emitting element 10 vertically (specifically, downward) by one light-receiving element pitch, and then moves the light-emitting element 10 horizontally (specifically, leftward) by one light-receiving element pitch. This makes it possible to suppress a decrease in the receiving sensitivity of each light-receiving element 30 due to the movement of the light-emitting element 10.

[0042] The control unit 110 controls the plurality of photoreceptors 30 so that a receiving operation (e.g., data reception) of optical communication with another optical communication device (communication partner) is performed using a photoreceptor group (G) consisting of only the photoreceptor element 30 with the highest pilot signal reception strength and the plurality of adjacent photoreceptors 30 adjacent to the photoreceptor element 30 with the highest reception strength. Specifically, the control unit 110 performs a receiving operation from the communication partner using only the photoreceptor group (G) corresponding to the direction in which the communication partner is located, rather than using all the photoreceptors 30 of the optical communication device 1. This makes it possible to reduce the power consumption and processing load of the optical communication device 1.

[0043] Here, the control unit 110 controls the multiple photodetectors 30 so that the photodetectors 30 not included in the photodetector group (G), i.e., the photodetectors 30 not used for receiving signals from the communication partner, perform a receiving operation (e.g., a searching operation) of a pilot signal from an optical communication device other than the communication partner with which optical communication is currently being performed, using the photodetectors 30. This allows the control unit 110 to detect a candidate optical communication device to which optical communication is to be switched (e.g., a handover destination) even during optical communication. From the viewpoint of reducing power consumption, it is preferable to perform such a searching operation intermittently. However, to further reduce power consumption, the control unit 110 may constantly suspend the photodetectors 30 not included in the photodetector group (G).

[0044] (3.2) Specific examples of movement control of light-emitting elements FIG. 7 is a diagram for explaining a first specific example of movement control of the light emitting element 10 according to the embodiment.

[0045] The control unit 110 stores in advance, as a movement position table, target movement positions (coordinates) of the light-emitting element 10 corresponding to the light-receiving element 30 (first light-receiving element) with the highest reception intensity and the light-receiving element 30 (second light-receiving element) with the second highest reception intensity. Then, the control unit 110 uses the movement position table to move the light-emitting element 10 to a position between the first and second light-receiving elements. In a first specific example, the first and second light-receiving elements are adjacent to each other, and the control unit 110 moves the light-emitting element 10 to an intermediate position between the first and second light-receiving elements.

[0046] FIG. 8 is a diagram for explaining a second specific example of movement control of the light emitting element 10 according to the embodiment.

[0047] In the second specific example, the first light receiving element and the second light receiving element are not adjacent to each other. In such a case, the control unit 110 uses the movement position table to move the light emitting element 10 to a target position that is near the first light receiving element and on a line connecting the first light receiving element and the second light receiving element.

[0048] FIG. 9 is a diagram for explaining a third specific example of movement control of the light emitting element 10 according to the embodiment.

[0049] In a third specific example, the first light receiving element and the second light receiving element are not adjacent to each other, and the second light receiving element is positioned diagonally relative to the first light receiving element. Using the movement position table, the control unit 110 moves the light emitting element 10 to a target position that is near the first light receiving element and on a line connecting the first light receiving element and the second light receiving element. However, if the line connecting the first light receiving element and the second light receiving element is diagonal, the target position may be a position slightly deviated from the line. For example, for simplicity, the angle may be rounded to the angle obtained by dividing the first light receiving element into approximately eight directions.

[0050] (3.3) Recovery operation when optical communication is interrupted FIG. 10 is a diagram for explaining a situation in which optical communication according to the embodiment is interrupted.

[0051] Due to factors such as obstacles, ambient light, multipath, or interference with other optical communication devices, the optical communication device 1 may experience high reception intensity in a direction different from that of the communication partner. In this case, the direction of the optical axis of the light-emitting element 10 may become distorted, causing a communication interruption. For example, if the optical communication device 1 is a terminal device, it may be able to receive downstream signals from a base station device, but may not receive upstream signals. The optical communication device 1 (control unit 110) determines that a communication interruption has occurred based on, for example, not receiving an acknowledgement (ACK) from the communication partner.

[0052] FIG. 11 is a diagram for explaining a recovery operation when optical communication is interrupted according to the embodiment.

[0053] When the control unit 110 detects that optical communication with another optical communication device (communication partner) has been interrupted, it controls the movement mechanism 40 to sequentially move (hereinafter also referred to as "scanning") the light-emitting element 10 from a position near the light-receiving element 30 where the reception intensity was greatest before the optical communication was interrupted in a direction away from the light-receiving element 30 until the optical communication is restored. Here, the control unit 110 may cause the light-emitting element 10 to emit light constantly during such scanning. Alternatively, the control unit 110 may cause the light-emitting element 10 to emit light periodically.

[0054] When moving the light-emitting element 10, the control unit 110 controls the movement mechanism 40 so that the light-emitting element 10 does not pass directly above each light-receiving element 30. For example, when moving the light-emitting element 10, the control unit 110 controls the movement mechanism 40 so that the light-emitting element 10 moves vertically and horizontally in a time-division manner. In FIG. 11 , the control unit 110 moves the light-emitting element 10 in the following order:

[0055] The light-emitting element 10 is moved upward by one light-receiving element pitch. -Move the light-emitting element 10 to the right by one light-receiving element pitch, The light-emitting element 10 is moved downward by one light-receiving element pitch. The light-emitting element 10 is moved downward by one light-receiving element pitch. -Move the light-emitting element 10 to the left by one light-receiving element pitch, -Move the light-emitting element 10 to the left by one light-receiving element pitch, The light-emitting element 10 is moved upward by one light-receiving element pitch. The light-emitting element 10 is moved upward by one light-receiving element pitch. The light-emitting element 10 is moved upward by one light-receiving element pitch. -Move the light-emitting element 10 to the right by one light-receiving element pitch, -Move the light-emitting element 10 to the right by one light-receiving element pitch, -Move the light-emitting element 10 to the right by one light-receiving element pitch, The light-emitting element 10 is moved downward by one light-receiving element pitch. The light-emitting element 10 is moved downward by one light-receiving element pitch. The light-emitting element 10 is moved downward by one light-receiving element pitch. The light-emitting element 10 is moved downward by one light-receiving element pitch.

[0056] Here, the control unit 110 may stop at each position determined in the movement position table (in the example of FIG. 11, at the midpoint between four adjacent light receiving elements 30) and cause the light emitting element 10 to emit light. If the control unit 110 receives an acknowledgement (ACK) from the communication partner during the scanning process, it may determine that optical communication has been restored and end the scanning (movement of the light emitting element 10). Note that the scanning range may be determined in advance to avoid scanning in a direction where there is clearly no communication partner (such as the back side of the sphere). For example, the control unit 110 may perform scanning within a range from a position near the light receiving element 30 where the reception intensity was maximum before the optical communication was interrupted to N receiving pixels as the upper limit.

[0057] (3.4) Operation flow FIG. 12 is a diagram showing an operation flow of the optical communication device 1 according to the embodiment.

[0058] In step S1, the control unit 110 controls the plurality of light receiving elements 30 so that they perform a receiving operation continuously or intermittently.

[0059] In step S2, at least one of the plurality of light receiving elements 30 receives a pilot signal from another optical communication device.

[0060] In step S3, the control unit 110 identifies the light receiving element 30 having the highest received pilot signal strength and the light receiving element 30 having the second highest received pilot signal strength.

[0061] In step S4, the control unit 110 sets (determines) the target position of the light-emitting element 10 using the movement position table based on the light-receiving element 30 identified in step S3.

[0062] In step S5, the control unit 110 controls the moving mechanism 40 to move the light emitting element 10 to the target position set in step S4.

[0063] In step S6, the control unit 110 performs optical communication with another optical communication device.

[0064] If the optical communication with the other optical communication device is completed (step S7: Yes), this flow ends. If the optical communication with the other optical communication device is not completed (step S7: No), the control unit 110 returns the process to step S1 and performs an operation to adjust the optical axis of the light-emitting element 10.

[0065] FIG. 13 is a diagram showing an operation flow when optical communication is interrupted in the optical communication device 1 according to the embodiment.

[0066] In step S101, the control unit 110 detects a disruption of optical communication.

[0067] In step S102, the control unit 110 attempts to restore optical communication by repeating the movement control of the light-emitting element 10 based on the reception status of the pilot signal a predetermined number of times (n times). If optical communication is restored (step S103: Yes), this flow ends.

[0068] If the optical communication is not restored (step S103: No), in step S104, the control unit 110 identifies the light receiving element 30 with the maximum reception intensity immediately before the optical communication was interrupted.

[0069] In step S105, the control unit 110 scans the light-emitting elements 10 (first scan) starting from the light-receiving element 30 identified in step S104, and attempts to restore optical communication.

[0070] In step S106, the control unit 110 moves the light emitting element 10 by a unit movement amount (for example, one light receiving element pitch). If the optical communication is restored (step S107: Yes), this flow ends.

[0071] If the optical communication has not been restored (step S107: No), in step S108, the control unit 110 determines whether or not scanning within the scanning range has been completed. If it determines that scanning within the scanning range has not been completed (step S108: No), the control unit 110 returns the process to step S106.

[0072] If it is determined that scanning within the scanning range has been completed (step S108: Yes), the control unit 110 determines whether the number of scans performed to restore the optical communication is equal to or greater than a predetermined number (m times). If the number of scans is equal to or greater than the predetermined number (m times) (step S109: Yes), in step S110, the control unit 110 determines that the optical communication with the communication partner is out of range and performs an out-of-range operation. If the number of scans is less than the predetermined number (m times) (step S109: No), the control unit 110 returns the process to step S102.

[0073] (4) First change example Next, a first modification of the optical communication device 1 according to the above embodiment will be described with reference to FIG.

[0074] The optical communication device 1 according to the first modified example has a sensor 120 for detecting shaking of the optical communication device 1. For example, an acceleration sensor can be used as the sensor 120. Based on the output of the sensor 120, the control unit 110 changes the control frequency, which is the frequency at which movement control of the light-emitting element 10 is performed based on the reception status of the pilot signal. This makes it possible to efficiently reduce the power consumption and processing load of the optical communication device 1.

[0075] For example, the control unit 110 controls the movement mechanism 40 based on the received intensity of the pilot signal (i.e., controls the movement of the light-emitting element 10) periodically at a first period as a default, and changes the period to a second period that is shorter or longer than the first period based on the output of the sensor 120. When a value indicating the shaking of the optical communication device 1 becomes equal to or greater than a predetermined value, the control unit 110 may change the period to a second period that is shorter than the first period so as to shorten the first period. When a value indicating the shaking of the optical communication device 1 becomes less than the predetermined value, the control unit 110 may change the period to a second period that is longer than the first period so as to extend the first period.

[0076] (5) Second Change Example Next, a second modification of the optical communication device 1 according to the above embodiment will be described with reference to FIG.

[0077] The optical communication device 1 according to the second modified example has an optical mechanism 60 for adjusting the beam angle of the light-emitting element 10. The optical mechanism 60 may include a lens and an actuator. The control unit 110 specifies a change frequency (i.e., the number of changes per unit time) that is the frequency at which the light-receiving element 30 with the highest pilot signal reception strength is changed. If the change frequency exceeds a predetermined frequency, the control unit 110 controls the optical mechanism 60 to expand the beam angle of the light-emitting element 10 (i.e., the spread of light).

[0078] If the frequency of the change is high, it is possible that the optical communication device 1 and / or the communication partner are shaking or moving a lot, or that there is an obstacle in the communication path. In such a case, the optical communication may be interrupted because the alignment of the light-emitting element 10 cannot keep up. Therefore, if the frequency of the change exceeds a predetermined frequency, this problem can be solved by increasing the beam angle of the light-emitting element 10.

[0079] For example, assuming that the beam angle of the light emitting element 10 is a first beam angle as a default, the control unit 110 changes the beam angle to a second beam angle that is narrower or wider than the first beam angle based on the change frequency. When the change frequency reaches a predetermined value or more, the control unit 110 may change the beam angle to a second beam angle that is wider than the first beam angle so as to widen the first beam angle. When the change frequency falls below a predetermined value, the control unit 110 may change the beam angle to a second beam angle that is narrower than the first beam angle so as to narrow the first beam angle.

[0080] Furthermore, when the control unit 110 controls the optical mechanism 60 to increase the beam angle of the light-emitting element 10, the control unit 110 may also control the optical mechanism 60 to decrease the throughput of optical communication with another optical communication device (communication partner) in accordance with the increase in the beam angle. Since increasing the beam angle reduces the amount of light reaching the communication partner, decreasing the optical communication throughput can increase transmission durability. Methods for decreasing the optical communication throughput include decreasing the operating frequency (clock frequency) of the light-emitting element 10 and / or changing the modulation and coding method.

[0081] In addition, when the optical communication device 1 includes the sensor 120 as in the first modification, the control unit 110 may control the optical mechanism 60 based on the output of the sensor 120.

[0082] (6) Third Change Example Next, a third modification of the optical communication device 1 according to the above embodiment will be described with reference to FIG.

[0083] The optical communication device 1 according to the second modification has a camera for capturing images. The control unit 110 controls the moving mechanism 40 based on the reception status of the pilot signal and the image data obtained by the camera .

[0084] For example, the control unit 110 may determine a target position for moving the light-emitting element 10 based on the reception intensity distribution of the optical signals received by the multiple light-receiving elements 30 and the position and / or direction of the communication partner estimated using the camera 130.

[0085] The control unit 110 may use the camera 130 during a recovery operation when optical communication is interrupted. For example, the control unit 110 may perform scanning by prioritizing the position and / or direction of the communication partner estimated using the camera 130. Alternatively, for example, the control unit 110 may determine the scanning range depending on the position and / or direction of the communication partner estimated using the camera 130.

[0086] (7) Fourth Change Example Next, a fourth modification of the optical communication device 1 according to the above embodiment will be described with reference to FIG.

[0087] In the optical communication device 1 according to the fourth modification, the main body 20 has a rod-like shape. Specifically, the main body 20 has a cylindrical shape. Similarly, the optically transparent housing 50 also has a cylindrical shape.

[0088] Figure 18 is a diagram showing the appearance of the optical communication device 1 viewed from above (direction "A" in Figure 17), and Figure 19 is a diagram showing the appearance of the optical communication device 1 viewed from the side (direction "B" in Figure 17).

[0089] The moving mechanism 40 of the fourth modified example has a rotating shaft 41 provided on the main body 20, a support member 45 rotatably supported by the rotating shaft 41 and rotatingly moving the light-emitting element 10 along the outer periphery of the rod-shaped shape, and a slide mechanism 46 supported by the support member 45 and moving the light-emitting element 10 along the longitudinal direction (vertical direction) of the rod-shaped shape.

[0090] The support members 45 have a wheel-like shape and are attached to both ends of the rotating shaft 41. The support members 45 rotate laterally as the rotating shaft 41 rotates. The slide mechanism 46 has both ends connected to the upper and lower support members 45. The slide mechanism 46 moves the light-emitting element 10 up and down in the vertical direction.

[0091] The control according to the above-described embodiment can also be applied to the optical communication device 1 configured in this way.

[0092] (8) Fifth Change Example Next, a fifth modification of the optical communication device 1 according to the above embodiment will be described with reference to FIG.

[0093] In the optical communication device 1 according to the fifth modification, the main body 20 has a rod-like shape, as in the above-described fourth modification. Specifically, the main body 20 has a cylindrical shape. Similarly, the optically transparent housing 50 also has a cylindrical shape. However, in the optical communication device 1 according to the fifth modification, the configuration of the movement mechanism 40 is different from that of the fourth modification.

[0094] Figure 21 is a diagram showing the appearance of the optical communication device 1 viewed from above (direction "A" in Figure 20), and Figure 22 is a diagram showing the appearance of the optical communication device 1 viewed from the side (direction "B" in Figure 20).

[0095] The movement mechanism 40 according to the fifth modified example includes a rotation shaft 41 provided on the main body 20, a support member 45 rotatably supported by the rotation shaft 41 and rotating and moving the light emitting element 10 along the outer periphery of the rod-shaped member, and a slide mechanism 46 supported by the support member 45 and moving the light emitting element 10 along the longitudinal direction (vertical direction) of the rod-shaped member. The slide mechanism 46 includes a vertical rail 46a whose both ends are connected to the upper and lower support members 45, a movable part 46b that moves along the rail 46a, and an arm 46c extending horizontally from the movable part 46b. The light emitting element 10 is attached to the arm 46c.

[0096] The control according to the above-described embodiment can also be applied to the optical communication device 1 configured in this way.

[0097] (9) Other embodiments In the above embodiment, an example has been described in which the main body 20 has a spherical shape. However, the spherical shape is not limited to a perfect sphere, and the main body 20 may be a polyhedron as shown in FIG. 23 . A light receiving element 30 is provided on each face of the polyhedron. Such a polyhedron is also included in the spherical main body 20. Furthermore, the spherical shape is not limited to a perfect sphere, and may be a hemisphere. When the main body 20 has a hemispherical shape, multiple light receiving elements 30 are arranged on the curved surface of the hemisphere.

[0098] In the fourth and fifth modified examples described above, an example was described in which the main body 20 has a cylindrical shape as the rod-like shape. However, the rod-like shape is not limited to a cylindrical shape, and the main body 20 may have a prismatic shape as shown in Fig. 24. A light receiving element 30 is provided on each side of the prismatic shape.

[0099] The above-described modifications are not limited to being implemented independently, and two or more modifications may be combined and implemented.

[0100] A program may be provided that causes a computer to execute each process performed by the optical communication device 1. The program may be recorded on a computer-readable medium. Using the computer-readable medium, the program can be installed on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited. For example, it may be a recording medium such as a CD-ROM or DVD-ROM. Furthermore, circuits that execute each process performed by the optical communication device 1 may be integrated, and at least a part of the optical communication device 1 may be configured as a semiconductor integrated circuit (chip set, SoC: System on a chip).

[0101] As used in this disclosure, the terms "based on" and "depending on / in response to" do not mean "based only on" or "depending only on," unless expressly stated otherwise. The term "based on" means both "based only on" and "based at least in part on." Similarly, the term "depending on" means both "depending only on" and "depending at least in part on." The terms "include," "comprise," and variations thereof do not mean including only the listed items, but may mean including only the listed items or including additional items in addition to the listed items. Additionally, the term "or," as used in this disclosure, is not intended to mean an exclusive or. Furthermore, any reference to elements using designations such as "first," "second," etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used herein as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way. In this disclosure, where articles are added by translation, such as a, an, and the in English, these articles shall include the plural unless the context clearly indicates otherwise.

[0102] The above describes the embodiments in detail with reference to the drawings, but the specific configuration is not limited to that described above, and various design changes can be made within the scope that does not deviate from the gist of the invention.

[0103] This application claims priority from Japanese Patent Application No. 2022-088396 (filed May 31, 2022), the entire contents of which are incorporated herein by reference.

[0104] (10) Supplementary Note Additional notes will be given regarding the features of the above-described embodiment.

[0105] (Appendix 1) A light-emitting element; a main body portion having a spherical or rod-like shape; a plurality of light receiving elements arranged at predetermined intervals on the surface of the main body; a moving mechanism that supports the light emitting element movably above the surface; a control unit that controls the moving mechanism to move the light emitting element to a position facing the other optical communication device based on a reception status of an optical signal received by the plurality of light receiving elements from the other optical communication device. Optical communication equipment.

[0106] (Appendix 2) The main body portion has the spherical shape, The moving mechanism includes: a first rotation shaft provided in the main body; a first arm that is rotatably supported by the first rotation shaft and that rotates the light emitting element in a first direction; a second rotation shaft provided on the first arm; a second arm that is rotatably supported by the second rotation shaft and that rotates and moves the light emitting element in a second direction perpendicular to the first direction; 2. The optical communication device of claim 1.

[0107] (Appendix 3) The main body portion has the rod-like shape, The moving mechanism includes: a rotation shaft provided in the main body; a support member that is rotatably supported by the rotation shaft and that rotates the light emitting element along an outer periphery of the rod-shaped shape; a slide mechanism supported by the support member and configured to move the light emitting element along the longitudinal direction of the rod-shaped shape; 2. The optical communication device of claim 1.

[0108] (Appendix 4) The control unit controls the moving mechanism to move the light emitting element to a target position near the light receiving element where the received intensity of the optical signal is greatest. 4. An optical communication device according to any one of claims 1 to 3.

[0109] (Appendix 5) The control unit Identifying a first light receiving element having the highest received intensity of the optical signal and a second light receiving element having the second lowest received intensity of the optical signal; The moving mechanism is controlled so as to move the light emitting element to a position on a line connecting the first light receiving element and the second light receiving element or a position in the vicinity of the line as the target position. 5. The optical communication device of claim 4.

[0110] (Appendix 6) The control unit controls the movement mechanism so that the light-emitting element does not pass directly above each light-receiving element when the light-emitting element is moved. 6. An optical communication device according to any one of claims 1 to 5.

[0111] (Appendix 7) The plurality of light receiving elements are arranged in a two-dimensional array in the vertical and horizontal directions, The control unit controls the movement mechanism so that, when moving the light-emitting element, the movement of the light-emitting element in the vertical direction and the movement of the light-emitting element in the horizontal direction are performed in a time-division manner. 7. The optical communication device of claim 6.

[0112] (Appendix 8) The control unit controls the plurality of light receiving elements so as to perform a receiving operation of the optical communication with the other optical communication device using a light receiving element group consisting of only a light receiving element having the maximum receiving intensity of the optical signal and a plurality of adjacent light receiving elements adjacent to the light receiving element having the maximum receiving intensity. 8. An optical communication device according to any one of claims 1 to 7.

[0113] (Appendix 9) The control unit controls the plurality of light receiving elements so that a light receiving element not included in the light receiving element group performs a receiving operation of a pilot signal from an optical communication device other than the other optical communication device. 9. The optical communication device of claim 8.

[0114] (Appendix 10) When the control unit detects that the optical communication with the other optical communication device has been interrupted, the control unit controls the movement mechanism to sequentially move the light-emitting element from a position near the light-receiving element where the reception intensity was maximum before the optical communication was interrupted in a direction away from the light-receiving element until the optical communication is restored. 10. An optical communication device according to any one of claims 1 to 9.

[0115] (Appendix 11) a sensor for detecting a vibration of the optical communication device; The control unit changes a control frequency, which is a frequency at which movement control of the light-emitting element based on the reception condition is performed, based on the output of the sensor. 11. An optical communication device according to any one of claims 1 to 10.

[0116] (Appendix 12) further comprising an optical mechanism for adjusting the directivity angle of the light emitting element; The control unit Identifying a change frequency, which is a frequency at which the light receiving element with the maximum reception strength of the optical signal is changed; When the change frequency exceeds a predetermined frequency, the optical mechanism is controlled to widen the beam angle. 12. An optical communication device according to any one of claims 1 to 11.

[0117] (Appendix 13) The control unit controls the optical mechanism to increase the beam angle and to decrease the throughput of the optical communication with the other optical communication device. 13. The optical communication device of claim 12.

[0118] (Appendix 14) further comprising a camera for capturing an image; The control unit controls the moving mechanism based on the reception status of the optical signal and the image data obtained by the camera. 14. An optical communication device according to any one of claims 1 to 13.

[0119] (Appendix 15) a housing that houses the light-emitting element, the main body, the plurality of light-receiving elements, and the movement mechanism; The housing is formed of a light-transmitting material. 15. An optical communication device according to any one of claims 1 to 14.

[0120] (Appendix 16) The optical communication device is an underwater optical communication device that performs underwater optical communication. 16. An optical communication device according to any one of claims 1 to 15.

[0121] (Appendix 17) An optical communication method performed in an optical communication device, comprising: receiving an optical signal from another optical communication device using a plurality of light receiving elements arranged at predetermined intervals on the surface of a main body having a spherical or rod-like shape; and controlling, based on a reception status of the optical signal, the light emitting element to be moved to a position facing the other optical communication device using a movement mechanism that movably supports the light emitting element above the surface. Optical communication method.

[0122] (Appendix 18) For optical communication devices, receiving an optical signal from another optical communication device using a plurality of light receiving elements arranged at predetermined intervals on the surface of a main body having a spherical or rod-like shape; and a step of controlling, based on a reception status of the optical signal, the light emitting element to be moved to a position facing the other optical communication device using a moving mechanism that movably supports the light emitting element above the surface. Optical communications program. [Explanation of symbols]

[0123] 1: Optical communication equipment 10: Light emitting element 20: Main body 30: Light receiving element 40: Movement mechanism 41: Rotation axis (first rotation axis) 42: First arm 43: Second rotation axis 44: Second arm 45: Support member 46: Slide mechanism 46a: Rail 46b: Moving part 46c: Arm 50: Housing 60:Optical mechanism 110: Control unit 111: Processor 112: Memory 120: Sensor 130: Camera 140: Communications Department

Claims

1. A light-emitting element; a main body portion having a spherical or rod-like shape; a plurality of light receiving elements arranged at predetermined intervals on the surface of the main body; a moving mechanism supported by the main body and configured to support the light emitting element above the surface so as to be movable relative to the main body; a control unit that controls the moving mechanism to move the light emitting element to a position facing the other optical communication device based on a reception status of an optical signal received by the plurality of light receiving elements from the other optical communication device. Optical communication equipment.

2. The main body portion has the spherical shape, The moving mechanism includes: a first rotation shaft provided in the main body; a first arm rotatably supported by the first rotation shaft and configured to rotate the light emitting element in a first direction; a second rotation shaft provided on the first arm; a second arm that is rotatably supported by the second rotation shaft and that rotates and moves the light emitting element in a second direction perpendicular to the first direction; 2. The optical communication device according to claim 1.

3. The main body portion has the rod-like shape, The moving mechanism includes: a rotation shaft provided in the main body; a support member that is rotatably supported by the rotation shaft and that rotates the light emitting element along an outer periphery of the rod-shaped shape; a slide mechanism supported by the support member and configured to move the light emitting element along the longitudinal direction of the rod-shaped shape; 2. The optical communication device according to claim 1.

4. The control unit controls the moving mechanism to move the light emitting element to a target position near the light receiving element where the received intensity of the optical signal is greatest.

2. The optical communication device according to claim 1.

5. The control unit Identifying a first light receiving element having the highest received intensity of the optical signal and a second light receiving element having the second lowest received intensity of the optical signal; The moving mechanism is controlled so as to move the light emitting element to a position on a line connecting the first light receiving element and the second light receiving element or a position in the vicinity of the line as the target position.

5. The optical communication device according to claim 4.

6. The control unit controls the movement mechanism so that the light-emitting element does not pass directly above each light-receiving element when the light-emitting element is moved.

2. The optical communication device according to claim 1.

7. The plurality of light receiving elements are arranged in a two-dimensional array in vertical and horizontal directions, The control unit controls the movement mechanism so that, when moving the light-emitting element, the movement of the light-emitting element in the vertical direction and the movement of the light-emitting element in the horizontal direction are performed in a time-division manner.

7. The optical communication device according to claim 6.

8. The control unit controls the plurality of light receiving elements so as to perform a receiving operation of the optical communication with the other optical communication device using a light receiving element group consisting of only a light receiving element having the maximum receiving intensity of the optical signal and a plurality of adjacent light receiving elements adjacent to the light receiving element having the maximum receiving intensity.

2. The optical communication device according to claim 1.

9. The control unit controls the plurality of light receiving elements so that a light receiving element not included in the light receiving element group performs a receiving operation of a pilot signal from an optical communication device other than the other optical communication device.

9. The optical communication device according to claim 8.

10. When the control unit detects that the optical communication with the other optical communication device has been interrupted, the control unit controls the movement mechanism to sequentially move the light-emitting element from a position near the light-receiving element where the reception intensity was greatest before the optical communication was interrupted in a direction away from the light-receiving element until the optical communication is restored.

2. The optical communication device according to claim 1.

11. a sensor for detecting a vibration of the optical communication device; The control unit changes a control frequency, which is a frequency at which movement control of the light-emitting element based on the reception condition is performed, based on the output of the sensor.

2. The optical communication device according to claim 1.

12. further comprising an optical mechanism for adjusting the directivity angle of the light emitting element; The control unit Identifying a change frequency, which is a frequency at which the light receiving element with the maximum reception strength of the optical signal is changed; When the change frequency exceeds a predetermined frequency, the optical mechanism is controlled to widen the beam angle.

2. The optical communication device according to claim 1.

13. The control unit controls the optical mechanism to increase the beam angle and to decrease the throughput of the optical communication with the other optical communication device.

13. The optical communication device according to claim 12.

14. further comprising a camera for capturing an image; The control unit controls the moving mechanism based on the reception status of the optical signal and the image data obtained by the camera.

2. The optical communication device according to claim 1.

15. a housing that houses the light-emitting element, the main body, the plurality of light-receiving elements, and the movement mechanism; The housing is formed of a light-transmitting material.

2. The optical communication device according to claim 1.

16. The optical communication device is an underwater optical communication device that performs underwater optical communication.

16. An optical communication device according to any one of claims 1 to 15.

17. An optical communication method performed in an optical communication device, comprising: receiving an optical signal from another optical communication device using a plurality of light receiving elements arranged at predetermined intervals on the surface of a main body having a spherical or rod-like shape; and controlling, based on a reception status of the optical signal, the light-emitting element to be moved to a position facing the other optical communication device using a movement mechanism that is supported by the main body and that supports the light-emitting element so as to be movable relative to the main body above the surface. Optical communication method.

18. For optical communication devices, receiving an optical signal from another optical communication device using a plurality of light receiving elements arranged at predetermined intervals on the surface of a main body having a spherical or rod-like shape; and a procedure of controlling, using a movement mechanism supported by the main body and supporting a light-emitting element above the surface so as to be movable relative to the main body based on a reception status of the optical signal, the light-emitting element to be moved to a position facing the other optical communication device. Optical communications program.

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