Communication control device and communication control method

Abstract

To provide a technique that can transmit data transmitted in a plurality of frames by effectively utilizing transmission time in a communication standard in which the transmission time is limited in a predetermined period.SOLUTION: When a communication control device acquires image data, the communication control device determines whether the image data can be transmitted based on the size of the image data and the total transmission time, which is the sum of transmission times of frames in a past predetermined period from the current time. If it determines that the image data cannot be transmitted, the communication control device calculates a waiting time based on the size of the image data and the total transmission time, and starts transmitting the image data after the waiting time has elapsed.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a communication control device and a communication control method for performing wireless communication based on a predetermined communication standard. [Background technology]

[0002] Patent Document 1 describes a technology that enables data aggregation between gateways taking into account transmission time restrictions, and prevents a gateway connected to a congested base station from being selected as the destination gateway. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-103527 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a wireless communication standard that limits the transmission time within a predetermined period, there is room for improvement in transmitting data in multiple frames while making effective use of the transmission time.

[0005] An object of the present invention is to provide a technology that makes it possible to transmit data transmitted in multiple frames by effectively utilizing the transmission time in a communication standard that limits the transmission time within a predetermined period. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention employs the following configuration.

[0007] (First Configuration) A communication control device according to a first configuration performs wireless communication based on a predetermined communication standard. The communication control device includes: acquisition means for acquiring transmission data transmitted in a plurality of frames; calculation means for calculating a total transmission time of the frames via the wireless communication over a predetermined period from the present time to the past; determination means for determining whether the acquired transmission data can be transmitted via the wireless communication within a predetermined upper limit time for the predetermined period based on the total transmission time calculated by the calculation means and the size of the transmission data acquired by the acquisition means; and control means for controlling transmission of the data via the wireless communication based on the result of the determination by the determination means. The control means starts transmission of the acquired transmission data if the determination means determines that the acquired transmission data can be transmitted; and starts transmission of the transmission data acquired by the acquisition means after waiting a waiting time during which the transmission data can be transmitted if the determination means determines that the acquired transmission data cannot be transmitted.

[0008] According to the above, when it is determined that the transmission data cannot be transmitted within the upper limit time, the transmission of the transmission data is started after waiting for the waiting time, so that the transmission data can be transmitted without interruption midway through the data transmission and without wasting transmission time.

[0009] (Second Configuration) In addition, in a second configuration, when the determination means determines that the acquired transmission data cannot be transmitted, the control means may calculate the waiting time based on the calculated total transmission time and the acquired transmission data, and after waiting for the calculated waiting time, start transmitting the transmission data acquired by the acquisition means.

[0010] According to the above, since the waiting time is dynamically calculated, it is possible to calculate an appropriate waiting time.

[0011] (Third Configuration) In addition, in a third configuration, in the second configuration, when the determination means determines that the acquired transmission data cannot be transmitted, the control means may calculate the waiting time such that the total transmission time plus the time required to transmit the acquired transmission data is less than or equal to the upper limit time.

[0012] According to the above, the waiting time is calculated so that the total transmission time plus the time required to transmit the transmission data is equal to or less than the upper limit time, so that a more appropriate and efficient waiting time can be calculated.

[0013] (Fourth Configuration) In addition, in a fourth configuration, in any of the first to third configurations, when the determination means determines that the acquired transmission data cannot be transmitted, the control means may wait for the waiting time and then start transmitting the transmission data that has been determined to be untransmittable.

[0014] Based on the above, when it is determined that transmission data cannot be transmitted, the transmission data determined to be unable to be transmitted can be transmitted after a waiting time has elapsed.

[0015] (Fifth Configuration) In addition, in a fifth configuration, in any of the first to third configurations, when the determination means determines that the acquired transmission data cannot be transmitted, the control means may wait for the waiting time and then start transmitting the transmission data that was acquired at the time the waiting time has elapsed or at any time within the waiting time and that the determination means determines can be transmitted.

[0016] Based on the above, when it is determined that transmission data cannot be transmitted, newer transmission data can be transmitted after a waiting time has elapsed.

[0017] (6th Configuration) In a sixth configuration, in any of the first to third configurations, the control means may include first control means that, when the determination means determines that the acquired transmission data cannot be transmitted, waits for the standby time and then starts transmitting the transmission data that has been determined to be untransmittable, and second control means that, when the determination means determines that the acquired transmission data cannot be transmitted, waits for the standby time and then starts transmitting the transmission data that has been acquired at a time when the standby time has elapsed or at an arbitrary time within the standby time and that has been determined to be transmittable by the determination means. The communication control device may further include selection means that selects between control by the first control means and control by the second control means based on a user operation.

[0018] Based on the above, the user can select either the control by the first control means or the control by the second control means.

[0019] (7th Configuration) In addition, in a seventh configuration, in any one of the first to sixth configurations, the transmission data may be image data from a camera.

[0020] Based on the above, it is possible to transmit image data as transmission data.

[0021] (8th Configuration) In an eighth configuration, the seventh configuration may further include a web request response unit configured to receive a web request from a user using the wireless communication and transmit a response to the web request. The acquisition unit may start acquiring image data from the camera in response to receiving the web request, and repeatedly acquire image data from the camera at a predetermined acquisition timing.

[0022] Based on the above, it is possible to start acquiring an image from a camera in response to a web request from a user.

[0023] (9th Configuration) A ninth configuration of the present invention provides a communication control device that performs wireless communication based on a predetermined communication standard. The communication control device includes: acquisition means for acquiring transmission data transmitted in a plurality of frames; calculation means for calculating a total transmission time of the frames via the wireless communication over a predetermined period from the present time; determination means for determining whether the acquired transmission data can be transmitted via the wireless communication within a predetermined upper limit time for the predetermined period based on the total transmission time calculated by the calculation means and the size of the transmission data acquired by the acquisition means; and control means for controlling transmission of the data via the wireless communication based on the result of the determination by the determination means. If the determination means determines that the acquired transmission data is transmittable, the control means starts transmitting the transmission data; and if the determination means determines that the acquired transmission data is not transmittable, the control means starts transmitting second transmission data that is smaller in size than the acquired transmission data and is determined by the determination means to be transmittable.

[0024] According to the above, when it is determined that the transmission data cannot be transmitted, it is possible to start transmitting second transmission data having a smaller size than the transmission data, and it is possible to start transmitting the second transmission data without interruption midway through the data transmission and without wasting transmission time.

[0025] (10th Component) In a tenth configuration, in the ninth configuration, the second transmission data may be part of the transmission data and may be high-priority data.

[0026] Based on the above, when it is determined that transmission data cannot be transmitted, it is possible to start transmission of second transmission data that is part of the transmission data and has a higher priority.

[0027] (11th Element) In addition, in an eleventh configuration, in the ninth or tenth configuration, the second transmission data may be second image data having a lower resolution than the image data determined to be unsendable, or having a higher compression rate than the image data determined to be unsendable.

[0028] Based on the above, when it is determined that image data cannot be transmitted, it is possible to start transmitting second image data having a lower resolution or a higher compression rate than the image data.

[0029] Another configuration may be a communication control method executed in the communication control device. [Effects of the Invention]

[0030] According to the present invention, transmission data can be transmitted without wasting transmission time. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a diagram showing an example of an image distribution system 1 using a communication control device 10 according to an embodiment of the present invention. [Figure 2] FIG. 1 shows an example of the configuration of a communication control device 10. [Figure 3] FIG. 10 is a diagram showing an overview of when a transmitting device transmits image data 50 using traffic shaping. [Figure 4] FIG. 1 is a diagram showing an overview when a transmitting device transmits image data at maximum throughput. [Figure 5] FIG. 10 is a diagram showing an example of a case where image data is transmitted when the communication control device 10 determines that the image data can be transmitted within the upper limit time. [Figure 6] FIG. 10 is a diagram showing an example of a case where the communication control device 10 determines that the image data cannot be transmitted within the upper limit time, and then waits for a waiting time Tw before transmitting the image data. [Figure 7] A diagram for explaining the waiting time Tw [Figure 8]FIG. 10 is a diagram showing an example of a case where, when the communication control device 10 determines that image data cannot be transmitted within the upper limit time, image data acquired at time t3 after waiting for the waiting time is transmitted. [Figure 9] FIG. 10 is a diagram showing an example of a case where, when the communication control device 10 determines that image data cannot be transmitted within the upper limit time, second image data having a size smaller than that of the image data is acquired and transmitted. [Figure 10] FIG. 1 is a diagram showing an example of data stored in the communication control device 10. [Figure 11] 1 is a flowchart showing an example of a main process performed in the communication control device 10. [Figure 12] 10 is a flowchart showing an example of the determination process in step S6. [Figure 13] A flowchart showing an example of the transmission process of step S8. [Figure 14] 10 is a flowchart showing an example of a second main process performed in the communication control device 10, in which new image data is acquired and transmitted after a waiting time Tw has elapsed. [Figure 15] 10 is a flowchart showing an example of a third main process performed in the communication control device 10, in which smaller second image data is acquired and transmitted. [Figure 16] FIG. 1 shows an example of an image distribution system 1 including a plurality of communication control devices 10. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate.

[0033] The embodiments described below each illustrate a specific example of the present invention. The numerical values, shapes, materials, components, the arrangement and connection of the components, the content and order of processing, etc. shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, at least some of the components in the following embodiments may be omitted, replaced with other components, or added.

[0034] An example of a communication control device of this embodiment will be described with reference to the drawings. Fig. 1 is a diagram showing an example of an image distribution system 1 using a communication control device 10 of this embodiment.

[0035] 1, the image distribution system 1 includes a communication control device 10, a camera 20, a distance sensor 21, an access point 30, and a user terminal 40. The camera 20 and the distance sensor 21 are connected to the communication control device 10.

[0036] The camera 20 is an imaging device that captures images (still images or video). The camera 20 captures images at appropriate times and transmits image data corresponding to the captured images to the communication control device 10. The distance sensor 21 is a sensor that outputs data corresponding to the distance to an object. For example, the distance sensor 21 is used so that the camera starts capturing images when an object comes within a predetermined distance. The distance sensor 21 may be disposed in the communication control device 10 or in the camera 20. The distance sensor 21 may also be disposed in a position different from the communication control device 10 and the camera 20. Note that a plurality of cameras 20 and / or distance sensors 21 may be provided.

[0037] The communication control device 10 and the access point 30 perform wireless communication based on a predetermined communication standard. The predetermined communication standard is a communication standard in which the total transmission time per unit time is limited to an upper limit time. For example, the predetermined communication standard is the IEEE802.11ah standard. For example, the communication control device 10 and the access point 30 are located at positions separated by a distance of several tens of meters to 1 km.

[0038] The access point 30 is connected to the user terminal 40, for example, by wired communication. The access point 30 and the user terminal 40 may be connected by wireless communication (for example, wireless communication conforming to a standard such as IEEE802.11a, 11b, 11g, 11n, 11ax, or 11be) or by wired communication (for example, wired communication conforming to a standard such as IEEE802.3). The access point 30 and the user terminal 40 may also be connected via a network (for example, a LAN or the Internet) using wireless communication and / or wired communication.

[0039] The user terminal 40 is, for example, a personal computer, a tablet terminal, a smartphone, or the like. The user terminal 40 includes an input device that accepts input from a user, a communication unit for communicating with the access point 30, and a monitor (all of which are not shown). For example, a web browser is installed in the user terminal 40, and the user terminal 40 can display web pages and also accept commands from the user via the input device. Note that a plurality of user terminals 40 may be provided.

[0040] Fig. 2 is a diagram showing an example of the configuration of the communication control device 10. As shown in Fig. 2, the communication control device 10 includes a processor 11, a memory 12, a storage device 13, an interface (I / F) 14 connected to a camera 20, an interface (I / F) 15 connected to a distance sensor 21, and a wireless communication unit 16.

[0041] The processor 11 is connected to a memory 12 for temporarily storing data. The processor 11 is also connected to a storage device 13 configured, for example, by a ROM, a nonvolatile memory, a hard disk, etc. The storage device 13 stores predetermined programs (for example, a communication control program for controlling wireless communication, which will be described later, a server program for realizing a web server, etc.). The processor 11 controls the communication control device 10 by executing the predetermined programs using the memory 12.

[0042] The processor 11 is connected to the camera 20 via an interface 14. The processor 11 functions as an acquisition unit that acquires image data representing an image captured by the camera 20 at an appropriate timing. The processor 11 is also connected to a distance sensor 21 via an interface 15. The processor 11 calculates the distance between the distance sensor 21 and an object in the detection direction of the distance sensor 21 based on the data output from the distance sensor 21.

[0043] The processor 11 is also connected to the wireless communication unit 16. The processor 11 transmits image data acquired from the camera 20 to the wireless communication unit 16. The wireless communication unit 16 includes an antenna (not shown), a circuit for controlling wireless communication, a program for controlling wireless communication, and a memory. The wireless communication unit 16 performs wireless communication based on a predetermined communication standard (e.g., the IEEE802.11ah standard). For example, the wireless communication unit 16 functions as a control unit that wirelessly transmits image data acquired from the processor 11 to the access point 30 using the predetermined communication standard. As will be described in detail later, for example, the wireless communication unit 16 functions as a determination unit that determines, before starting transmission of image data, whether the image data can be transmitted within an upper limit time based on the total frame transmission time over a predetermined period from the present time to the past and the size of the image data. Furthermore, for example, the wireless communication unit 16 calculates the time required to transmit the image data using the predetermined communication standard before starting transmission of the image data. Furthermore, for example, the wireless communication unit 16 stores a frame transmission history. Note that, for example, the processor 11 may function as the determination unit.

[0044] The interface 14 and the camera 20 may be connected by wire or wirelessly. Furthermore, the interface 14 and the camera 20 may be connected, for example, via a network (e.g., LAN). Furthermore, the interface 15 and the distance sensor 21 may be connected by wire or wirelessly. Furthermore, the interface 15 and the distance sensor 21 may be connected via a network (e.g., LAN).

[0045] The camera 20 and the communication control device 10 are installed, for example, in a factory, facility, office, parking lot, park, dam, river, mountain, etc., and the user terminal 40 and the access point 30 are installed at a location relatively far from these. For example, the camera 20 and the communication control device 10 are installed in a factory to monitor a predetermined image capture target on a production line. The access point 30 is installed at a location several tens of meters to 1 km away from the communication control device 10. Furthermore, the user terminal 40 is installed, for example, at a location relatively far from the image capture target in the factory. A user uses the user terminal 40 to remotely monitor the predetermined image capture target.

[0046] For example, a web server program is stored in the storage device 13, and the processor 11 executes the program to cause the communication control device 10 to function as a web server. A user accesses the communication control device 10 using, for example, a browser on the user terminal 40. In response to the access, the communication control device 10 transmits a command to the camera 20 to start capturing an image. In response to the command, the camera 20 starts capturing an image.

[0047] In addition, when the communication control device 10 detects the proximity of an object based on data from the distance sensor 21, for example, when it determines that the distance to the object is less than a threshold, it may send a command to the camera 20 to start acquiring images.

[0048] The communication control device 10 acquires image data from the camera 20 and transmits the image data to the access point 30 using a predetermined communication standard (for example, IEEE802.11ah). Specifically, the communication control device 10 divides the image data from the camera 20 into multiple frames and transmits them wirelessly to the access point 30 based on the predetermined communication standard. The access point 30 receives the multiple frames from the communication control device 10 and transmits them to the user terminal 40. The user terminal 40 receives the image data by receiving the multiple frames and outputs the image data to a monitor.

[0049] In Japan, a specific communication standard (e.g., IEEE802.11ah) limits the sum of frame transmission times in a specific period (hereinafter referred to as the "total transmission time") to an upper limit. For example, the total transmission time per hour is limited to 10% (360 seconds) or less. The types of frames transmitted by the communication control device 10 include data frames for transmitting data such as image data, management frames such as beacons, and control frames such as ACK frames. In the specific communication standard, the total frame transmission time in a specific period is limited to an upper limit, regardless of the frame type. When the total frame transmission time reaches the upper limit, the communication control device 10 must stop transmitting frames. When the total frame transmission time in a specific period falls below the upper limit, the communication control device 10 can transmit frames.

[0050] To prevent such frame transmission from being stopped, traffic shaping may be performed on the transmitting device. For example, traffic shaping can average the frame transmission time and adjust the transmission interval of each frame to prevent the total transmission time in a given period from exceeding the upper limit.

[0051] FIG. 3 is a diagram showing an outline of when a transmitting device transmits image data 50 using traffic shaping.

[0052] As shown in FIG. 3, when relatively large data such as image data 50 is transmitted, the image data 50 is divided into multiple partial data (e.g., 50a to 50d) and transmitted in multiple frames. When the frame transmission interval is adjusted to be longer by traffic shaping, the total transmission time in a predetermined period can be prevented from exceeding the upper limit time. For example, if image transmission periods of 3 seconds each at 30-second intervals are preset, the total transmission time in the predetermined period can be prevented from exceeding 10% (the upper limit time). However, if the transmission interval between each frame is long, the time from receiving the first partial data 50a of the image data 50 to receiving the last partial data 50d becomes long on the receiving side. As a result, for example, it may take a long time from the first display of a portion of an image to the complete image being displayed on the receiving side, which may cause an unnatural display to the viewer.

[0053] On the other hand, when data transmission intervals are not lengthened by traffic shaping and data is transmitted at maximum throughput, the time from receiving the first partial data 50a of the image data 50 to receiving the last partial data 50d is shortened.

[0054] FIG. 4 is a diagram showing an overview when a transmitting device transmits image data at maximum throughput.

[0055] 4, when the transmitting device transmits image data 50 at the maximum throughput, the image data 50 can be transmitted in a short time if the total transmission time in a predetermined period does not exceed the upper limit time. On the other hand, when the transmitting device is transmitting partial data of the image data 51, the total transmission time in a predetermined period may reach the upper limit time.

[0056] For example, if a transmitting device transmits the first half of partial data 51b of image data 51 and the total transmission time for a predetermined period reaches the upper limit, the transmitting device stops transmitting frames. In this case, the transmitting device stops transmitting frames until the total transmission time for the predetermined period falls below the upper limit, and then resumes transmitting the remaining second half of partial data 51c and 51d of image data 51. However, if the period during which frame transmission is suspended is long, a timeout may occur in the application or OS on the transmitting or receiving side of image data 51, and the data may be discarded. In this case, although the transmitting device transmits the second half of partial data 51c and 51d, the data is not used on the receiving side, resulting in a waste of valuable transmission time.

[0057] 3 and 4, the communication control device 10 (e.g., wireless communication unit 16) of this embodiment determines whether the image data can be transmitted within an upper time limit based on the total transmission time from the current time to a predetermined past period and the size of the image data before starting transmission of the image data. The communication control device 10 controls the transmission of the data based on the result of this determination.

[0058] FIG. 5 is a diagram showing an example of a case where image data is transmitted when the communication control device 10 determines that the image data can be transmitted within the upper limit time.

[0059] As shown in Figure 5, the communication control device 10 acquires image data 50 from the camera 20 and determines whether the image data 50 can be transmitted within the upper limit time based on the size of the image data 50 and the total transmission time from the present time to a predetermined period in the past.

[0060] Specifically, before starting transmission of the image data 50, the communication control device 10 (e.g., wireless communication unit 16) calculates the time required to transmit the image data 50 using a predetermined communication standard (hereinafter referred to as the "required transmission time"). Next, the communication control device 10 calculates the remaining transmission time, which is the difference between the upper limit time and the total transmission time over a predetermined period of time from the present time, and determines whether the remaining transmission time is equal to or greater than the required transmission time. If the remaining transmission time is equal to or greater than the required transmission time, the communication control device 10 determines that the image data 50 can be transmitted.

[0061] For example, if the size of the image data 50 is 3 Mbits and the maximum throughput is 3 Mbps, the required transmission time for transmitting the image data 50 is approximately 1 second. If the remaining transmission time at the current time is 1 second or more, the communication control device 10 determines that the image data 50 can be transmitted. Note that, taking into account the overhead when transmitting the image data 50 in multiple frames, the communication control device 10 may determine that the image data can be transmitted if the remaining transmission time is longer than the required transmission time by a predetermined time (e.g., 3 seconds). If it is determined that the image data 50 can be transmitted, the communication control device 10 transmits the image data 50 at the maximum throughput. Specifically, the communication control device 10 divides the image data 50 into multiple partial data and transmits the divided multiple partial data in multiple frames.

[0062] Next, a process will be described when the communication control device 10 determines that the image data cannot be transmitted within the upper limit time. Fig. 6 is a diagram showing an example of a case where the communication control device 10 determines that the image data cannot be transmitted within the upper limit time, and then waits for a waiting time Tw before transmitting the image data. Fig. 7 is a diagram for explaining the waiting time Tw.

[0063] 6, the communication control device 10 temporarily stores image data 50 acquired from the camera 20 at time t1, and if it determines that the image data 50 cannot be transmitted within the upper limit time, starts transmitting the image data 50 at time t3 after the waiting time Tw has elapsed. The communication control device 10 calculates the required transmission time for the image data 50 and calculates the waiting time Tw such that the remaining transmission time is greater than the required transmission time.

[0064] As shown in Fig. 7, the communication control device 10 (e.g., the wireless communication unit 16) stores a history of frame transmissions from the current time t1 to a predetermined time period in the past. For example, the communication control device 10 stores the transmission times of frames from the current time to a predetermined time period in the past, and the time required to transmit the frames (i.e., the transmission time). The stored transmission times of frames may be expressed in standard time or in terms of the time from the current time. The sum of the transmission times of each frame from the current time to a predetermined time period in the past is the total transmission time Ts.

[0065] For example, the total transmission time Tsa from the current time t1 to the past predetermined period A is "T1+T2+T3+T4." Therefore, the remaining transmission time at this time t1 is the upper limit time Tm-Tsa (T1+T2+T3+T4). This remaining transmission time is shorter than the required transmission time Tr of the image data 50. Therefore, the communication control device 10 determines that the image data 50 cannot be transmitted at the current time t1.

[0066] Furthermore, the total transmission time Tsb from time t2, which is some time elapsed from the current time t1, during the past predetermined period B is "T2 + T3 + T4." Predetermined periods A and B have different starting times, but are the same length. The remaining transmission time at time t2 is Tm - Tsb (T2 + T3 + T4), which is shorter than the required transmission time Tr. Therefore, the communication control device 10 determines that the image data 50 cannot be transmitted even at time t2.

[0067] Meanwhile, the total transmission time Tsc for the predetermined period C from time t3, which is further time elapsed from the current time t1, is "T3 + T4." The predetermined periods A and C have different starting times but are of the same length. The remaining transmission time at time t3 is the upper limit time Tm - Tsc (T3 + T4), which is longer than the required transmission time Tr. Therefore, the communication control device 10 determines that the image data 50 can be transmitted at time t3.

[0068] When it is determined that the image data 50 cannot be transmitted at the current time t1, the communication control device 10 calculates the total transmission time from the current time t1 to a future time based on the frame transmission history stored in the device, and searches for the time t3 at which the image data 50 can be transmitted, as shown in Fig. 7. Then, the communication control device 10 calculates the difference between the time t3 and the time t1 as the waiting time Tw.

[0069] Note that when the communication control device 10 periodically transmits a management frame (e.g., a beacon), the communication control device 10 determines whether the image data 50 can be transmitted at the current time t1, taking into consideration the transmission time of the periodically transmitted management frame. For example, the communication control device 10 determines whether the total transmission time at the current time t1 plus the required transmission time of the image data 50 and the transmission time of the management frame is equal to or less than the upper limit time Tm. If the communication control device 10 determines that the image data 50 can be transmitted at the current time t1, it starts transmitting the image data 50 at the current time t1. If the periodic transmission timing of the management frame arrives while the image data 50 is being transmitted, the communication control device 10 transmits the management frame. On the other hand, if the communication control device 10 determines that the image data 50 cannot be transmitted at the current time t1, it refers to the frame transmission history and calculates the waiting time Tw based on the required transmission time of the image data 50 and the transmission time of the management frame. The communication control device 10 can predict the transmission timing and transmission time of the management frame at the current time t1. For example, the communication control device 10 can predict whether to transmit a management frame and, if so, the transmission time, during the period from the current time t1 to time t3 shown in Fig. 7. The communication control device 10 calculates the waiting time Tw during which the image data 50 can be transmitted, taking into account not only the required transmission time for the image data 50 but also the predicted transmission time for the management frame.

[0070] 6, if the communication control device 10 determines that the image data 50 cannot be transmitted within the upper limit time, it temporarily stores the image data 50 and stops transmitting the image data until the calculated waiting time Tw has elapsed. At time t3 when the waiting time Tw has elapsed, the communication control device 10 starts transmitting the temporarily stored image data 50. Specifically, the communication control device 10 divides the image data 50 into a plurality of partial data and transmits the partial data using a plurality of frames at the maximum throughput.

[0071] 6, if it is determined that the image data 50 acquired at time t1 cannot be transmitted, the image data 50 determined to be untransmittable is transmitted after the waiting time Tw has elapsed. Alternatively, instead of the image data 50 determined to be untransmittable, the communication control device 10 may transmit image data acquired from the camera 20 within the waiting time Tw (i.e., within the period between time t1 and time t3), or image data acquired from the camera 20 at time t3 after the waiting time Tw has elapsed.

[0072] FIG. 8 is a diagram showing an example of a case where, when the communication control device 10 determines that image data cannot be transmitted within the upper limit time, image data acquired at time t3 after waiting for the waiting time is transmitted.

[0073] As shown in FIG. 8, if the communication control device 10 determines at time t1 that the image data 50 acquired from the camera 20 cannot be transmitted within the upper limit time, the communication control device 10 discards the image data 50 and calculates the waiting time Tw. The calculation of the waiting time Tw is as described above. The communication control device 10 stops transmitting the image data until the calculated waiting time Tw has elapsed, and then acquires new image data 51 from the camera 20 at time t3 after the waiting time Tw has elapsed. The communication control device 10 determines whether the image data 51 can be transmitted within the upper limit time based on the size of the new image data 51 and the total transmission time at time t3. Even in this case, the transmission time of the management frame may be taken into consideration, as described above. If the communication control device 10 determines that the image data 51 can be transmitted, the communication control device 10 divides the image data 51 into multiple partial data and transmits the partial data using multiple frames at the maximum throughput. If the communication control device 10 determines that the image data 51 cannot be transmitted, the communication control device 10 again calculates the waiting time Tw and waits for the calculated waiting time Tw.

[0074] The image data whose transmission starts at time t3 after the waiting time Tw has elapsed may be image data acquired from camera 20 during the waiting time Tw. For example, image data acquired at any time during the waiting time Tw, such as time t2, may be transmitted starting at time t3. Of course, an image acquired at time t1 may also be held for Tw and transmitted.

[0075] Here, when the communication control device 10 determines that the image data cannot be transmitted, it may acquire second image data of a size smaller than the image data determined to be unable to be transmitted, and start transmitting the second image data, without waiting for the waiting time.

[0076] FIG. 9 is a diagram showing an example of a case where, when the communication control device 10 determines that image data cannot be transmitted within the upper limit time, second image data having a size smaller than that of the image data is acquired and transmitted.

[0077] 9, if the communication control device 10 determines at time t1 that the image data 50 acquired from the camera 20 cannot be transmitted within the upper limit time, the communication control device 10 acquires second image data 60 having a size smaller than that of the image data 50. For example, the processor 11 of the communication control device 10 may transmit to the camera 20 a command to acquire the second image data 60 having a lower resolution than the image data 50, and acquire the second image data 60 from the camera 20. The processor 11 of the communication control device 10 may also acquire the second image data 60 by compressing the image data 50 at a higher compression rate. The communication control device 10 divides the acquired second image data 60 into a plurality of partial data and transmits the partial data using a plurality of frames at the maximum throughput without waiting at time t1.

[0078] When the communication control device 10 acquires the second image data 60, the communication control device 10 may again determine whether the second image data 60 can be transmitted based on the size of the second image data 60 and the total transmission time for a predetermined period of time from time t1. The communication control device 10 may repeatedly acquire second image data of a smaller size until it determines that the second image data can be transmitted. Alternatively, the communication control device 10 may acquire the second image data and determine whether it can be transmitted a predetermined number of times, and if it has not determined that the second image data can be transmitted even after acquiring the second image data the predetermined number of times, it may not transmit the image at time t1.

[0079] (Data stored in the communication control device) Next, a description will be given of data stored in the communication control device 10. Fig. 10 is a diagram showing an example of data stored in the communication control device 10.

[0080] 10, a server program, a communication control program, image data, transmission history data, total transmission time data, required transmission time data, and standby time data are stored in the communication control device 10. These data are stored in a memory within the communication control device 10 (for example, in any of the memory 12, the storage device 13, and the memory within the wireless communication unit 16).

[0081] The server program is a program for causing the communication control device 10 to function as a Web server. When the processor 11 executes the server program, the communication control device 10 functions as a Web server.

[0082] The communication control program is a program for controlling wireless communication based on a predetermined communication standard, and is a program for executing the processing according to the flowchart described below.

[0083] The image data is image data acquired from the camera 20. The image data may be data representing a still image or data representing a moving image.

[0084] The transmission history data indicates a history of frame transmissions over a predetermined period of time from the present to the past. The transmission history data may include, for example, the start time of frame transmission and the duration of the transmission over the predetermined period. The transmission history data is stored, for example, in a memory within the wireless communication unit 16.

[0085] The total transmission time data indicates the total transmission time Ts of frames over a predetermined period from the present to the past. The total transmission time Ts is calculated based on the transmission history data. The total transmission time data is stored in, for example, a memory in the wireless communication unit 16.

[0086] The required transmission time data is data indicating the required transmission time Tr required when transmitting image data acquired from the camera 20. The required transmission time data is calculated based on the size of the image data.

[0087] The waiting time data is data indicating the waiting time Tw calculated when the communication control device 10 determines that image data cannot be transmitted.

[0088] (Details of processing in the communication control device) Next, a detailed description will be given of the processing performed in the communication control device 10. Fig. 11 is a flowchart showing an example of main processing performed in the communication control device 10. The processing shown in Fig. 11 is performed by the processor 11 or the wireless communication unit 16 of the communication control device 10 executing a predetermined program (for example, a server program, a communication control program).

[0089] 11, the communication control device 10 (for example, the processor 11) determines whether or not there has been a web access from the user terminal 40 (step S1). Specifically, the communication control device 10 functions as a web server and waits for an access (for example, an HTTP request) from the user terminal 40. The communication control device 10 repeatedly executes the process of step S1 until there is a web access from the user terminal 40.

[0090] If it is determined that there has been a web access from the user terminal 40 (step S1: YES), the communication control device 10 performs the processes from step S2 onwards. Specifically, the communication control device 10 starts capturing an image in response to the web access from the user terminal 40 (step S2) and returns a response to the web access (for example, an HTTP response) (step S3). In the response, the communication control device 10 transmits a web page for image distribution to the user terminal 40.

[0091] Specifically, in step S2, communication control device 10 transmits a command to camera 20 to start capturing an image. Camera 20 captures an image in response to the command and transmits the image data to communication control device 10. Thereafter, communication control device 10 repeatedly executes the processes of steps S4 to S12 to repeatedly acquire image data from camera 20 and transmits the acquired images to user terminal 40 via access point 30.

[0092] 11, if the communication control device 10 receives a command to stop image transmission while repeatedly executing the processes of steps S4 to S12, the communication control device 10 ends the processes of steps S4 to S12 and returns the process to step S1. For example, if the browser is closed on the user terminal 40, a command to stop image transmission is transmitted from the user terminal 40 to the communication control device 10.

[0093] Furthermore, with regard to the timing for starting image capture by camera 20, for example, communication control device 10 may execute a process for determining whether to start capturing an image based on data from distance sensor 21, instead of or in addition to step S1. For example, communication control device 10 may determine whether an object has been detected, or whether the distance to the object is less than (or greater than) a threshold, based on data from distance sensor 21. Then, when an object is detected, or when the distance to the object is less than (or greater than) the threshold, communication control device 10 may transmit a command to camera 20 to start capturing an image.

[0094] After step S3, the communication control device 10 determines whether it is time to transmit an image (step S4). For example, the processor 11 may determine YES in step S4 at predetermined time intervals (for example, every few seconds to several tens of seconds) using a timer provided therein. Alternatively, for example, the browser of the user terminal 40 may request the communication control device 10 to transmit an image at predetermined time intervals, and the processor 11 may determine YES in step S4 when the request is received. Note that the predetermined time interval is variable and may be set by the user. For example, a web page displayed on the browser of the user terminal 40 may allow the user to select from multiple options the time interval for acquiring images from the camera 20. Alternatively, the user may be able to input an arbitrary value as the predetermined time interval.

[0095] If it is determined that it is time to transmit an image (step S4: YES), the communication control device 10 acquires image data from the camera 20 and stores it in memory (step S5). The communication control device 10 then performs a determination process (step S6). The determination process is a process for determining whether data transmitted in multiple frames based on a predetermined communication standard (hereinafter referred to as "transmission data") can be transmitted. In the determination process, whether transmission is possible is determined based on the size of the transmission data (for example, the image data acquired in step S5). The process of step S6 will be described in detail below with reference to FIG. 12.

[0096] The processes of steps S6 to S11 may be performed by the wireless communication unit 16. At least one of the processes of steps S6 to S11 may be performed by the processor 11.

[0097] (Determination process) FIG. 12 is a flowchart showing an example of the determination process in step S6.

[0098] 12, the communication control device 10 (for example, the wireless communication unit 16) first determines whether the data to be transmitted is transmission data to be transmitted in multiple frames (step S20). Specifically, the communication control device 10 determines whether the size of the data to be transmitted exceeds the size that can be transmitted in one frame.

[0099] If the determination in step S20 is YES, the communication control device 10 calculates the required transmission time Tr required to transmit the transmission data based on the size of the transmission data (step S21). For example, the communication control device 10 calculates the required transmission time Tr of the image data based on the size of the image data acquired in step S5. The communication control device 10 stores the calculated required transmission time Tr in memory as required transmission time data.

[0100] Next, the communication control device 10 calculates the total transmission time Ts, which is the sum of the transmission times of frames from the present time to a predetermined past period, based on the transmission history data (step S22). The communication control device 10 stores the calculated total transmission time Ts in memory as total transmission time data.

[0101] Next, the communication control device 10 calculates the remaining transmission time, which is the difference between a predetermined upper limit time (for example, a time equivalent to 10% of a predetermined period) and the total transmission time Ts (step S23).

[0102] Next, the communication control device 10 determines whether the calculated remaining transmission time is equal to or greater than the required transmission time Tr (step S24).

[0103] If the remaining transmission time is equal to or greater than the required transmission time Tr, the communication control device 10 determines that the transmission data can be transmitted (step S25). On the other hand, if the remaining transmission time is less than the required transmission time Tr, the communication control device 10 determines that the transmission data cannot be transmitted (step S26).

[0104] On the other hand, if the determination in step S20 is NO (i.e., the data to be transmitted is data that can be transmitted in one frame), the communication control device 10 determines whether the frame can be transmitted in consideration of a predetermined upper limit time (step S27). Specifically, the communication control device 10 calculates the total transmission time Ts from the present time to a predetermined period in the past based on the transmission history data, and determines whether the total transmission time Ts is equal to or less than the upper limit time.

[0105] If the determination in step S27 is YES, the communication control device 10 next executes the process of step S25, and if the determination in step S27 is NO, the communication control device 10 next executes the process of step S26.

[0106] When the communication control device 10 has performed the process of step S25 or step S26, it ends the process shown in FIG. 12 and returns the process to the flow of FIG.

[0107] Returning to FIG. 11, the communication control device 10 determines whether or not it has been determined in the determination process of step S6 that the transmission data can be transmitted (step S7).

[0108] If it is determined that the transmission data can be transmitted (step S7: YES), the communication control device 10 executes a transmission process (step S8). Details of the transmission process in step S8 will be described below.

[0109] (Transmission process) FIG. 13 is a flowchart showing an example of the transmission process in step S8.

[0110] 13, the communication control device 10 generates one frame (step S31). For example, when transmitting transmission data (e.g., image data acquired in step S5) that is transmitted in multiple frames, the communication control device 10 divides the transmission data into multiple partial data pieces that are equal to or smaller than the maximum transmission size of one frame, and generates one frame that includes the partial data pieces.

[0111] Next, the communication control device 10 wirelessly transmits the frame generated in step S31 based on a predetermined communication standard (step S32). For example, the communication control device 10 transmits the frame in a manner conforming to the 802.11ah standard. When the communication control device 10 transmits a frame, it stores information indicating the transmission time and transmission duration of the frame in memory as transmission history data. The transmission history data stores a history of frame transmissions at least for a predetermined period of time from the present time to the past.

[0112] Next, the communication control device 10 determines whether data transmission is complete (step S33). Here, the communication control device 10 determines whether all of the transmission data has been transmitted. For example, when transmitting image data, the communication control device 10 determines whether all of the multiple partial data into which the image data has been divided have been transmitted. Note that if the size of the data to be transmitted is equal to or smaller than the maximum transmission size of one frame, the communication control device 10 determines YES in step S33.

[0113] If the data transmission is not completed (step S33: NO), the communication control device 10 executes the process of step S31 again.

[0114] On the other hand, if the data transmission is completed (step S33: YES), the communication control device 10 ends the process of FIG. 13 and returns to the flow of FIG.

[0115] Returning to FIG. 11, after the transmission process of step S8 has been performed, the communication control device 10 then executes the process of step S4.

[0116] On the other hand, if the determination in step S7 is NO, the communication control device 10 holds the transmission data (for example, the image data acquired in step S5) to be transmitted in multiple frames (step S9). For example, the communication control device 10 holds the image data acquired and saved in step S5 in memory. For example, the transmission data may be held in memory in the wireless communication unit 16 or in memory 12.

[0117] Next, the communication control device 10 calculates the waiting time Tw (step S10). Specifically, the communication control device 10 calculates the waiting time Tw at which the remaining transmission time will be equal to or greater than the required transmission time Tr, based on the transmission history data. For example, the communication control device 10 calculates the total transmission time from the present time after a predetermined time has elapsed, based on the transmission history data, calculates the remaining transmission time after the predetermined time has elapsed, and compares the remaining transmission time with the required transmission time Tr. Then, the communication control device 10 calculates the waiting time Tw at which the remaining transmission time will be equal to or greater than the required transmission time Tr. Note that the communication control device 10 may calculate the total transmission time and calculate the waiting time Tw, taking into account the transmission time of a management frame that is periodically transmitted.

[0118] After the process of step S10, the communication control device 10 determines whether or not the waiting time Tw has elapsed (step S11). The communication control device 10 repeats the determination of step S11 until the waiting time Tw has elapsed.

[0119] If the waiting time Tw has elapsed (step S11: YES), the communication control device 10 proceeds to step S8, whereby the transmission data held in step S9 starts to be transmitted in step S8.

[0120] On the other hand, if the determination in step S4 is NO, the communication control device 10 determines whether to transmit another frame (step S12). For example, if the wireless communication unit 16 acquires data to be transmitted other than image data from an application, the determination in step S12 is YES. For example, if the wireless communication unit 16 acquires transmission data to be transmitted in multiple frames other than image data from an application, the determination in step S12 is YES. Furthermore, for example, if the wireless communication unit 16 is to transmit data related to a web page to the user terminal 40, the determination in step S12 is YES. Furthermore, for example, if it is time to transmit a management frame, the wireless communication unit 16 determines YES in step S12.

[0121] If it is determined that another frame is to be transmitted (step S12: YES), the communication control device 10 proceeds to step S6.

[0122] On the other hand, if it is determined that another frame is not to be transmitted (step S12: NO), the communication control device 10 executes the process of step S4 again.

[0123] As described above, in FIG. 11, when the communication control device 10 acquires transmission data transmitted in multiple frames, it determines whether the transmission data can be transmitted based on the total transmission time over a predetermined period from the present to the past and the size of the transmission data. If the communication control device 10 determines that the transmission data cannot be transmitted, it temporarily stores the transmission data and calculates the waiting time Tw. After the waiting time Tw has elapsed, the communication control device 10 starts transmitting the temporarily stored transmission data. This allows the communication control device 10 to prevent the total transmission time over a predetermined period from exceeding the upper limit while transmitting the transmission data, and prevents frame transmission from being stopped while transmitting the transmission data. Therefore, the transmission data can be transmitted without wasting transmission time.

[0124] (Second main process) Next, a second main process will be described in which communication control device 10 acquires and transmits new image data after the standby time Tw has elapsed, i.e., when transmission becomes possible. Fig. 14 is a flowchart showing an example of the second main process performed by communication control device 10, and is a flowchart showing a case in which new image data is acquired and transmitted after the standby time Tw has elapsed. In Fig. 14, the same processes as in Fig. 11 are assigned the same step numbers, and descriptions thereof will be omitted.

[0125] 14, if the communication control device 10 determines NO in step S7, it discards the transmission data without saving it, and calculates the waiting time Tw (step S10). If the waiting time Tw has elapsed (step S11: YES), the communication control device 10 proceeds to step S5. Here, the communication control device 10 acquires new image data from the camera 20 at the point in time when the waiting time Tw has elapsed. The communication control device 10 performs a determination process on the newly acquired image data in step S6, and if it determines that the newly acquired image data can be transmitted, starts transmission in step S8.

[0126] 14, when communication control device 10 acquires transmission data, it determines whether the transmission data can be transmitted, and if it determines that the transmission data cannot be transmitted, it discards the transmission data and calculates standby time Tw. When standby time Tw has elapsed, communication control device 10 performs a determination process on image data acquired from camera 20 at the time that standby time Tw has elapsed, and if it determines that the image data can be transmitted, it starts transmitting the image data. This allows communication control device 10 to transmit the latest image data without wasting transmission time.

[0127] If the determination in step S7 is NO, the communication control device 10 may acquire image data from the camera 20 at any time before the waiting time Tw has elapsed, and may start transmitting any of the image data acquired during that period after the waiting time Tw has elapsed. For example, the smallest image data among the image data acquired during that period may start to be transmitted after the waiting time Tw has elapsed. In this way, it is possible to prepare for transmission of a new image during the waiting time, and transmit the new image immediately after the waiting time has elapsed, without first acquiring the image from the camera.

[0128] (Third main process) Next, a third main process will be described in which, when the communication control device 10 determines that the transmission data cannot be transmitted, smaller second transmission data is acquired and transmitted. Fig. 15 is a flowchart showing an example of the third main process performed in the communication control device 10, and is a flowchart showing a case in which smaller second image data is acquired and transmitted. In Fig. 15, the same processes as in Fig. 11 are assigned the same step numbers, and descriptions thereof will be omitted.

[0129] 15, if the determination in step S7 is NO, the communication control device 10 acquires second image data (step S16). For example, the processor 11 may acquire second image data obtained by compressing the image data acquired in step S5 at a higher compression rate. Alternatively, the processor 11 may send a command to the camera 20 to acquire an image with a lower resolution (i.e., an image with a smaller size), and acquire the second image data with a lower resolution from the camera 20.

[0130] After acquiring the second image data, the communication control device 10 then performs a determination process in step S6. In this determination process, it is determined whether the second image data can be transmitted based on the size of the acquired second image data. If the communication control device 10 determines that the second image data can be transmitted (step S7: YES), it starts transmitting the second image data in step S8.

[0131] 15, when communication control device 10 acquires transmission data, it determines whether the transmission data can be transmitted, and if it determines that the transmission data cannot be transmitted, it acquires second transmission data that is smaller in size than the transmission data that it determined cannot be transmitted. The communication control device 10 performs a determination process on the acquired second transmission data, and if it determines that the second transmission data can be transmitted, it starts transmitting the second transmission data. This allows communication control device 10 to immediately acquire the smaller second transmission data and start transmitting it without wasting transmission time.

[0132] [Effects of this embodiment] As described above, the communication control device 10 according to this embodiment determines whether the transmission data is transmittable before starting transmission of the transmission data, and starts transmission of the transmission data if it determines that the transmission is transmittable. This makes it possible to transmit transmission data that is transmitted in multiple frames without wasting transmission time.

[0133] Furthermore, in this embodiment, if it is determined that the transmission data cannot be transmitted, the waiting time is calculated based on the total transmission time and the size of the transmission data, and the transmission of the transmission data is started after waiting for the waiting time, thereby making it possible to calculate an appropriate waiting time.

[0134] Furthermore, in this embodiment, when it is determined that transmission of the transmission data is impossible, a waiting time is calculated such that the total transmission time plus the required transmission time of the transmission data is equal to or less than the upper limit time. This allows an appropriate waiting time to be calculated.

[0135] In addition, in this embodiment, if it is determined that transmission data cannot be transmitted, the transmission of the transmission data determined to be untransmittable is started after waiting for the waiting time, thereby making it possible to transmit the transmission data determined to be untransmittable.

[0136] In addition, in this embodiment, if it is determined that the transmission data cannot be transmitted, the device waits for a waiting time, and then transmits the transmission data acquired at the time when the waiting time has elapsed or during the waiting period, thereby enabling the transmission of newer transmission data.

[0137] Furthermore, in this embodiment, when it is determined that the transmission data cannot be transmitted, second transmission data smaller in size than the transmission data is obtained and transmitted, thereby enabling the smaller second transmission data to be transmitted immediately.

[0138] [Variations] The above embodiment is merely an example, and the following modifications may be made.

[0139] For example, the communication control device 10 may be configured as a device integrated with the camera 20 and / or the distance sensor 21. For example, the communication control device 10 may be a network camera equipped with the camera 20. The communication control device 10 may also be configured as a wireless module incorporated in another device. For example, the communication control device 10 may be configured as a wireless module having a wireless communication function for performing wireless communication in accordance with the IEEE802.11ah standard, a function for controlling the camera 20, and the above-mentioned web server function.

[0140] Furthermore, in the above embodiment, the communication control device 10 functions as a web server, but the web server function may be provided in a separate device. For example, the camera 20, the web server, and the communication control device 10 may be configured as separate devices and connected by wired communication (or wireless communication). In this case, when a user accesses the web server using a browser on the user terminal 40, the web server sends a command to the camera 20 to start capturing an image, and the camera 20 starts capturing an image in response to the command. The camera 20 transmits image data to the communication control device 10, and the communication control device 10 transmits the image data to the access point 30 based on a predetermined communication standard through the processing described above.

[0141] In the above embodiment, still image data from the camera 20 is transmitted from the communication control device 10 to the access point 30 as transmission data transmitted in multiple frames. In other embodiments, moving image data from the camera 20 may be transmitted from the communication control device 10 to the access point 30 as transmission data.

[0142] Furthermore, any data, not limited to image data, may be transmitted from the communication control device 10 to the access point 30 as transmission data transmitted in multiple frames. For example, sensor data acquired from various sensors (e.g., acceleration sensors, angular velocity sensors, temperature sensors, humidity sensors, pressure sensors, distance sensors, etc.) may be transmitted as transmission data. Data indicating control commands for controlling a device may also be transmitted as transmission data. Data indicating voice or character strings may also be transmitted as transmission data.

[0143] In the above embodiment, when the communication control device 10 determines that transmission data cannot be transmitted, it calculates a waiting time based on the size of the transmission data and starts transmitting the transmission data after the waiting time has elapsed. In other embodiments, the waiting time may be a predetermined fixed time. Alternatively, the waiting time may be a time set by the user.

[0144] Furthermore, the communication control device 10 may be configured to be capable of executing a main process and a second main process, and to be capable of selecting and executing either the main process or the second main process. For example, whether to perform control based on the main process or the second main process may be set based on a user operation. That is, the communication control device 10 may be configured to be capable of executing a first process of storing transmission data and starting transmission of the stored transmission data after a standby time has elapsed when it is determined that transmission data cannot be transmitted, and a second process of starting transmission of transmission data acquired at the time the standby time has elapsed or within the standby time when it is determined that transmission data cannot be transmitted. The communication control device 10 may be capable of selecting and executing either the first process or the second process.

[0145] In the above embodiment, the main processing, the second main processing, and the third main processing have been described. The communication control device 10 may be configured to be able to execute the main processing, the second main processing, and the third main processing. In this case, the communication control device 10 may select and execute one of the main processing, the second main processing, and the third main processing based on, for example, a user operation.

[0146] In the above embodiment, if the communication control device 10 determines in the third main process that the transmission data cannot be transmitted, the communication control device 10 acquires second transmission data smaller in size than the transmission data determined to be untransmittable. Specifically, the communication control device 10 acquires image data with a lower resolution or with a higher compression rate as the second transmission data, assuming that image data is to be acquired as the transmission data. In other embodiments, the second transmission data may be a portion of the transmission data determined to be untransmittable. This portion of data may be high-priority data among the transmission data for which it is undesirable to wait for transmission during the standby time. For example, consider a case in which transmission data including multiple data with different priorities (e.g., first data with a higher priority and second data with a lower priority) is transmitted. In this case, if the communication control device 10 determines that the transmission data cannot be transmitted, the communication control device 10 may acquire the first data with a higher priority from the transmission data as the second transmission data and start transmitting it. The multiple data with different priorities may be, for example, data related to the status of the monitored object (e.g., data indicating physical quantities such as temperature, pressure, or current, or data qualitatively indicating a status such as an error or warning).

[0147] Furthermore, in the above embodiment, the image distribution system 1 includes one communication control device 10. However, in other embodiments, the image distribution system 1 may include multiple communication control devices 10. FIG. 16 is a diagram illustrating an example of an image distribution system 1 including multiple communication control devices 10. As illustrated in FIG. 16, the image distribution system 1 includes a communication control device 10a to which a camera 20 is connected, a communication control device 10b, an access point 30, and a user terminal 40. For example, the communication control device 10a and the communication control device 10b are separated by approximately several tens of meters to 1 km. The communication control device 10b and the access point 30 are separated by approximately several tens of meters to 1 km. The communication control device 10a acquires image data from the camera 20 and transmits the image data to the communication control device 10b based on a predetermined communication standard. The communication control device 10b receives the image data and transmits the image data to the access point 30 based on the predetermined communication standard. When transmitting image data, the communication control devices 10a and 10b perform the determination process (FIG. 12) and transmission process (FIG. 13) described above. In this way, image data from the camera 20 may be transmitted to the user terminal 40 via the communication control device 10a and the communication control device 10b. Note that image data from the camera 20 may be transmitted to the user terminal 40 via three or more communication control devices 10.

[0148] Furthermore, the configuration and operational aspects of the communication control device 10 described in the above embodiment are merely examples, and it goes without saying that the present invention can be realized with other configurations and operational aspects. Furthermore, the order and values ​​of each step in the above flowchart are merely examples, and other orders and values ​​may be used, or other steps may be added to the flowchart, or some of the steps may be omitted or modified. Furthermore, the diagrams and the like illustrated in the above embodiment are merely examples, and other aspects may be used.

[0149] The above-mentioned numerical values ​​are merely examples, and the present invention is not limited to the above-mentioned embodiment, but various modifications and applications are possible. Furthermore, the above-mentioned embodiment and modifications can be mutually applied, and the present invention can be realized in various combinations. [Explanation of symbols]

[0150] 1. Image distribution system 10. Communication control device 11 processors 16. Radio Communication Department 20 Camera 21 Distance Sensor 30 access points 40 User terminals 50, 51 Image data 60 Second image data

Claims

1. A communication control device that performs wireless communication based on a predetermined communication standard, an acquisition means for acquiring transmission data transmitted in a plurality of frames; a calculation means for calculating a total transmission time of the frames via wireless communication from the present time to a predetermined past time period; a determination means for determining whether the acquired transmission data can be transmitted using the wireless communication within a predetermined upper limit time in the predetermined period, based on the total transmission time calculated by the calculation means and the size of the transmission data acquired by the acquisition means; and a control unit that controls transmission of data using the wireless communication based on a result of the determination by the determination unit; The control means When the determination means determines that the acquired transmission data can be transmitted, the transmission of the transmission data is started; A communication control device that, when the determination means determines that the acquired transmission data cannot be transmitted, waits for a waiting time until the transmission data can be transmitted, and then starts transmitting the transmission data acquired by the acquisition means.

2. The control means 2. The communication control device according to claim 1, wherein, when the determination means determines that the acquired transmission data cannot be transmitted, the waiting time is calculated based on the calculated total transmission time and the acquired transmission data, and after waiting for the calculated waiting time, transmission of the transmission data acquired by the acquisition means is started.

3. The control means 3. The communication control device according to claim 2, wherein when the determination means determines that the acquired transmission data cannot be transmitted, the waiting time is calculated so that the total transmission time plus the time required to transmit the acquired transmission data is equal to or less than the upper limit time.

4. The control means 2. The communication control device according to claim 1, wherein, when the determination means determines that the acquired transmission data cannot be transmitted, the control device waits for the waiting time and then starts transmitting the transmission data that has been determined to be untransmittable.

5. The control means 2. The communication control device according to claim 1, wherein, when the determination means determines that the acquired transmission data cannot be transmitted, the communication control device waits for the waiting time, and then starts transmitting the transmission data that the determination means determines to be transmittable and that was acquired at the time when the waiting time has elapsed or at any time within the waiting time.

6. The control means a first control means for, when the determination means determines that the acquired transmission data cannot be transmitted, waiting for the waiting time and then starting transmission of the transmission data that has been determined to be untransmittable; a second control means for, when the determination means determines that the acquired transmission data cannot be transmitted, waiting for the standby time, and then starting transmission of the transmission data that is acquired at the point in time when the standby time has elapsed or at any point in time within the standby time and that is determined by the determination means to be transmittable, The communication control device according to claim 1 , further comprising a selection unit that selects control by said first control unit or control by said second control unit based on a user operation.

7. 7. The communication control device according to claim 1, wherein the transmission data is image data from a camera.

8. a web request response unit configured to receive a web request from a user using the wireless communication and to transmit a response to the web request; The communication control device according to claim 7 , wherein the acquisition means starts acquiring image data from the camera in response to receiving the Web request, and repeatedly acquires image data from the camera at predetermined acquisition timings.

9. A communication control device that performs wireless communication based on a predetermined communication standard, an acquisition means for acquiring transmission data transmitted in a plurality of frames; a calculation means for calculating a total transmission time of the frames via wireless communication from the present time to a predetermined past time period; a determination means for determining whether the acquired transmission data can be transmitted using the wireless communication within a predetermined upper limit time in the predetermined period, based on the total transmission time calculated by the calculation means and the size of the transmission data acquired by the acquisition means; and a control unit that controls transmission of data using the wireless communication based on a result of the determination by the determination unit; The control means When the determination means determines that the acquired transmission data can be transmitted, the transmission of the transmission data is started; A communication control device that, when the determination means determines that the acquired transmission data cannot be transmitted, starts transmitting second transmission data that is smaller in size than the acquired transmission data and is determined by the determination means to be transmittable.

10. The communication control device according to claim 9 , wherein the second transmission data is a part of the transmission data and is data with a high priority.

11. 11. The communication control device according to claim 9, wherein the second transmission data is second image data having a lower resolution than the image data determined to be unsendable, or a higher compression rate than the image data determined to be unsendable.

12. A communication control method for performing wireless communication based on a predetermined communication standard, an acquisition step of acquiring transmission data transmitted in a plurality of frames; a calculation step of calculating a total transmission time of the frames via wireless communication from a current time point to a predetermined past time period; a determination step of determining whether the acquired transmission data can be transmitted using the wireless communication within a predetermined upper limit time in the predetermined period, based on the total transmission time calculated in the calculation step and the size of the transmission data acquired in the acquisition step; a control step of controlling transmission of data using the wireless communication based on a result of the determination in the determination step, In the control step, If it is determined in the determining step that the acquired transmission data can be transmitted, transmission of the transmission data is started; A communication control method, wherein if it is determined in the determination step that the acquired transmission data cannot be transmitted, the method waits for a waiting time until the transmission data can be transmitted, and then starts transmitting the transmission data acquired in the acquisition step.

13. A communication control method for performing wireless communication based on a predetermined communication standard, an acquisition step of acquiring transmission data transmitted in a plurality of frames; a calculation step of calculating a total transmission time of the frames via wireless communication from a current time point to a predetermined past time period; a determination step of determining whether the acquired transmission data can be transmitted using the wireless communication within a predetermined upper limit time in the predetermined period, based on the total transmission time calculated in the calculation step and the size of the transmission data acquired in the acquisition step; a control step of controlling transmission of data using the wireless communication based on a result of the determination in the determination step, In the control step, If it is determined in the determining step that the acquired transmission data can be transmitted, transmission of the transmission data is started; A communication control method, wherein if it is determined in the determination step that the acquired transmission data cannot be transmitted, transmission of second transmission data that is smaller in size than the acquired transmission data and is determined in the determination step to be transmittable is started.

Images