Radio device, communication system, radio device control method, and program

Abstract

To perform appropriate communication control depending on a change in radio environment.SOLUTION: A radio device 10 comprises: an acquisition unit 131 for acquiring a time used for transmission of data to a second communication device 22 in a first period including the current time as its end and a time used by the radio device 10 for transmission of a management frame; an estimation unit 132 that uses the time used for transmission of the data, the time used for transmission of the management frame, and a time to be used for transmission of the management frame in a second period including the current time as its start to estimate a time available for transmission of new data to the second communication device 22 in the second period so that the total sum of radio transmission times in the first period and the second period does not exceed a predetermined time ratio with respect to the total sum of the first period and the second period; and a calculation unit 133 for calculating a communication band available for transmission of the new data to the second communication device 22 by multiplying the time available for transmission of the new data by a data rate.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a wireless device, a communication system, a control method for a wireless device, and a program. [Background technology]

[0002] IEEE standard 802.11ah (hereinafter referred to as 802.11ah) is one of the wireless communication methods that uses frequencies in the 920MHz band, and is expected to be used in various fields, especially as a communication system for IoT (Internet of Things). For example, 802.11ah does not require a unique protocol or dedicated system, and has high compatibility with existing IP (Internet Protocol) assets and commercially available IP-based devices, so it has the advantage of being able to effectively utilize existing IP assets. In addition, for example, 802.11ah is a standard that uses unlicensed bands that do not require licenses, and has the advantage that base stations and terminals can be freely installed according to the usage scenario.

[0003] However, in the frequency band used in 802.11ah (for example, the 920 MHz band), the Radio Law stipulates that radio waves may only be transmitted for up to 360 seconds per hour. In order to comply with this regulation, for example, Patent Document 1 discloses a wireless communication system that limits the total transmission time per unit time from the transmission of radio waves to a first time limit or less, permits wireless transmission at a transmission timing for each predetermined transmission cycle, and controls transmission so that the wireless transmission time per transmission is less than a second time limit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-104026 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the technology described in Patent Document 1, for example, the transmission time limit per unit time can be observed after radio waves are transmitted due to the first and second time limits, but on the other hand, there are cases where appropriate communication control cannot be performed according to the ever-changing wireless environment. Also, if it is in accordance with the rule that radio waves must not be transmitted when the upper limit of the transmission time limit per unit time is reached, communication will suddenly be cut off at the time the upper limit of the transmission time limit is reached, and data to be transmitted will be retransmitted only after a certain amount of time has passed, which may prevent appropriate communication control, in other words, may reduce communication efficiency.

[0006] The present invention has been made to solve the above problems, and has an object to provide a wireless device or the like that can perform appropriate communication control in response to changes in the wireless environment. [Means for solving the problem]

[0007] In order to solve the above problem, a wireless device according to one aspect of the present invention is a wireless device that transmits data acquired from a first communication device to a second communication device using a predetermined communication standard, the predetermined communication standard being a wireless transmission available time per unit time that is limited to a predetermined time ratio or less, the wireless device includes an acquisition unit that acquires a time used by the wireless device to transmit the data to the second communication device and a time used by the wireless device to transmit a management frame during a first period ending at a current time, and an acquisition unit that acquires a time used by the wireless device to transmit the data to the second communication device and a time used by the wireless device to transmit a management frame during a second period starting at the current time. an estimation unit that estimates a time available for the wireless device to transmit new data to the second communication device during the second period, using a time used to transmit a frame, such that a sum of a wireless transmission time in the first period and a wireless transmission time in the second period does not exceed a predetermined time ratio with respect to a total time of the first period and the second period; and a calculation unit that calculates a communication bandwidth available for the wireless device to transmit the new data to the second communication device during the second period by multiplying the time available for transmitting the new data by a data rate, which is a communication speed between the wireless device and the second communication device.

[0008] According to this, when the wireless device acquires new data from the first communication device, it can estimate the time available for transmitting new data to the second communication device in the next certain time from the time used for transmitting data to the second communication device in a first period ending at the current time (in other words, the most recent transmission record). Furthermore, the wireless device can calculate the communication bandwidth available for transmitting new data to the second communication device by multiplying the estimated time by the data rate at the current time. Therefore, even if the data rate varies depending on the state of wireless communication, the wireless device can calculate the communication bandwidth available for transmitting new data to the second communication device in accordance with the variation in the data rate. Therefore, the wireless device can perform appropriate communication control in accordance with changes in the wireless environment.

[0009] In addition, the wireless device may further include a bandwidth limiting unit that limits the communication speed of data that the wireless device acquires from the first communication device during the second period, in accordance with the communication bandwidth calculated by the calculation unit.

[0010] According to this, the wireless device can limit the communication speed of new data acquired from the first communication device during the second time period starting from the current time, in accordance with the communication bandwidth calculated by the calculation unit, and therefore the wireless device can limit the amount of new data acquired from the first communication device to the amount that can be transmitted to the second communication device within the time available for transmission.

[0011] In addition, the wireless device may further include a bandwidth limiting unit that transmits control information to the first communication device including an instruction to limit the communication speed of the new data that the first communication device transmits to the wireless device during the second period, in accordance with the communication bandwidth calculated by the calculation unit.

[0012] According to this, the wireless device can limit the communication speed of new data transmitted from the first communication device to the wireless device during the second time period starting from the current time, in accordance with the communication bandwidth calculated by the calculation unit, and therefore the wireless device can limit the amount of new data transmitted from the first communication device to the amount that can be transmitted within the time available for transmission to the second communication device.

[0013] The first period and the second period may have the same time length.

[0014] According to this, the wireless device can control communications in a control cycle of the same length of time, so that it becomes easy to perform appropriate communication control in response to changes in the wireless environment.

[0015] The wireless device may also include the first communication device.

[0016] According to this, the wireless device is less susceptible to the communication environment, and therefore it becomes easier to adjust the amount of data acquired from the first communication device.

[0017] The predetermined communication standard may be IEEE802.11ah.

[0018] This allows the wireless device to perform appropriate communication control in response to changes in the wireless environment even under IEEE802.11ah.

[0019] Moreover, a communication system according to one embodiment of the present invention comprises the above-mentioned wireless device and the first communication device, wherein the first communication device performs a compression process on moving image data and transmits the compressed moving image data as the data, and the wireless device sets a compression ratio for the compression process of the first communication device during the second period in accordance with the communication bandwidth calculated by the calculation unit, and transmits the set compression ratio to the first communication device.

[0020] This allows the communication system to transmit moving image data compressed at an appropriate compression rate in response to changes in the wireless environment.

[0021] Also, a control method of a wireless device according to one aspect of the present invention is a control method of a wireless device for transmitting data acquired from a first communication device to a second communication device using a predetermined communication standard, the predetermined communication standard being a standard that limits a wireless transmittable time per unit time to a predetermined time ratio or less, the wireless device including an acquisition step of acquiring a time used by the wireless device to transmit the data to the second communication device and a time used by the wireless device to transmit a management frame during a first period ending at a current time, and a control method of a wireless device for transmitting the data to the second communication device using a predetermined communication standard, the control method of the wireless device including an acquisition step of acquiring a time used by the wireless device to transmit the data to the second communication device and a time used by the wireless device to transmit a management frame during a second period starting at the current time. a calculation step of calculating a communication bandwidth available for the wireless device to transmit the new data to the second communication device in the second period by multiplying the time available for transmitting the new data by a data rate, which is a communication speed between the wireless device and the second communication device, by the time available for transmitting the new data by the data rate, which is a communication speed between the wireless device and the second communication device.

[0022] This provides the same effects as the wireless device described above.

[0023] A program according to an aspect of the present invention is a program for causing one or more computers to execute the above-described control method for a wireless device.

[0024] This provides the same effects as the wireless device described above.

[0025] The present invention can be realized not only as an apparatus, but also as a method in which the processing means constituting the apparatus are steps, as a program for causing a computer to execute those steps, as a computer-readable recording medium such as a CD-ROM on which the program is recorded, or as information, data or signals indicating the program.These programs, information, data and signals may be distributed via a communication network such as the Internet. Effect of the Invention

[0026] According to the present invention, a wireless device can perform appropriate communication control in response to changes in the wireless environment. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is an explanatory diagram showing the operation of a conventional wireless device. [Diagram 2] FIG. 2 is a graph showing the transition of the time that a wireless device uses for management frames. [Diagram 3] FIG. 3 is a graph showing the transition of the remaining time when a communication load is applied to the wireless device in the situation shown in FIG. [Figure 4] FIG. 4 is a schematic diagram illustrating an example of a configuration of a communication system including a wireless device according to an embodiment. [Diagram 5] FIG. 5 is a flow diagram illustrating an example of a process executed by a wireless device according to the embodiment. [Figure 6] FIG. 6 is a schematic diagram for explaining an example of the operation of the band limiting unit in the band limiting step. [Figure 7] FIG. 7 is a first diagram for specifically explaining the estimation process executed by the wireless device according to the embodiment. [Figure 8] FIG. 8 is a second diagram for specifically illustrating the estimation process executed by the wireless device according to the embodiment. [Figure 9]FIG. 9 is a third diagram for specifically explaining the estimation process executed by the wireless device according to the embodiment. [Figure 10] FIG. 10 is a fourth diagram for specifically explaining the estimation process executed by the wireless device according to the embodiment. [Figure 11] FIG. 11 is a schematic diagram for explaining another example of the operation of the band limiting unit in the band limiting step. [Figure 12] FIG. 12 is a schematic diagram for explaining an example of the operation of the band limiting unit when the wireless device includes the first communication device. [Figure 13] FIG. 13 is a schematic diagram illustrating an example of the configuration of a video distribution system including a wireless device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] (Findings that led to the present invention) First, a conventional wireless device and its problems will be described. Fig. 1 is an explanatory diagram showing the operation of a conventional wireless device.

[0029] As explained in the Background section, in Japan, for 802.11ah using the 920MHz band, there is a rule that radio waves can only be transmitted for 360 seconds per hour (i.e., the transmittable time ratio is 10%). In other words, for 802.11ah, radio waves can only be transmitted for 10% of the time, that is, the time ratio during which radio waves can be transmitted is 10% of the time. The above time ratio is also called the specified time ratio.

[0030] Conventional wireless devices comply with the above rules by controlling communications so as not to violate the above rules (more specifically, so that radio wave transmission does not exceed 360 seconds per hour) by limiting the total transmission time per unit time from the start of radio wave transmission to a time limit or less.

[0031] For example, as shown in FIG. 1, when a conventional wireless device transmits data acquired from a first communication device to a second communication device, if there is data (also called a communication packet) that would cause the wireless transmission time per transmission to exceed a time limit, the conventional wireless device adjusts the amount of data to be transmitted to the second communication device by discarding the data (communication packet) before transmission.

[0032] In this way, conventional wireless devices control wireless communication with the second communication device, but discard data that would be transmitted beyond the time limit, which may result in a decrease in the quality of applications or services that use communication (for example, frame drops in applications transmitting video data, or audio skipping, etc.).

[0033] In order to avoid the above-mentioned degradation in quality, there is a method of adjusting the data transmission rate to the second communication device without discarding the data obtained from the first communication device as described above. However, this method is considered to be difficult to implement due to the following reasons (1) or (2).

[0034] (1) The communication band that the wireless device can use to communicate with the second communication device changes in conjunction with the data rate. Note that the data rate is the transmission speed of signals in communication between the wireless device and the second communication device, and changes depending on the wireless environment.

[0035] (2) The time that the wireless device uses for management frames cannot be subject to bandwidth restrictions. Generally, the wireless device often transmits management frames to the second communication device at the slowest data rate. The management frame referred to here is a management frame in wireless communication that is used for communication necessary to maintain wireless communication.

[0036] An example of the time that a wireless device uses for a management frame will be described with reference to FIG.

[0037] 2 is a graph showing the transition of the time used by a wireless device for management frames. Here, the unit time (also called management unit time) managed as the time span used to calculate the transmission time is set to be shorter than 1 hour (i.e., 3600 seconds), for example, 1 minute (i.e., 60 seconds). That is, in this example, communication control is performed so that the transmission time is limited to 6 seconds for the management unit time of 1 minute (i.e., 60 seconds) while keeping the predetermined time ratio of 10%, rather than limiting the transmission time to 360 seconds for the management unit time of 1 hour (i.e., 3600 seconds).

[0038] 2, the horizontal axis of the graph indicates time when the time when the wireless device is turned on is set as time 0. The vertical axis of the graph indicates the time (also called the remaining time) that the wireless device can use to communicate with the second communication device during a 6-second period starting from the current time.

[0039] In Fig. 2, the remaining time is shown every two seconds. The remaining time is calculated every two seconds by subtracting the time that the wireless device has spent transmitting frames (also called spent time) during the 60-second period ending at that point in time from the time limit of six seconds.

[0040] When the wireless device is powered on, it starts transmitting a management frame, and repeats transmitting the management frame at a predetermined cycle. As a result, the remaining time shown in FIG. 2 decreases over time. The management frame is, for example, a beacon frame. The wireless device transmits a beacon frame once every 100 milliseconds. In this case, if one beacon frame transmission time is 3.3 milliseconds, the transmission time consumed during the management unit time of 60 seconds is 600 times x 3.3 milliseconds, or about 2 seconds.

[0041] Once 60 seconds have elapsed since the power was turned on, the time used to transmit management frames for more than 60 seconds prior to that point in time is no longer included in the consumed time (in other words, that consumed time is no longer counted as past transmission results). Therefore, the remaining time at times after 60 seconds has elapsed is maintained at approximately 4 seconds, balancing the decrease in the time used to transmit management frames for more than 60 seconds prior to that point in time with the increase in the time used to transmit new management frames.

[0042] Here, since the management frame is always transmitted at the slowest data rate, the time used for the management frame is constant and does not change. Note that in FIG. 2, a beacon frame is used as an example of a management frame in wireless communication, but this is not limiting. In other words, any communication that is necessary to maintain wireless communication and that is performed at a predetermined time in a specified cycle may be used. Specifically, this includes communication performed when updating DHCP (Dynamic Host Configuration Protocol).

[0043] In such a situation, if the wireless device transmits data in addition to transmitting a management frame, the situation shown in Fig. 3 may occur. Fig. 3 is a graph showing the transition of the remaining time when the wireless device transmits data and a communication load is applied in the situation shown in Fig. 2. Here, an example is shown in which the wireless device starts to obtain data from the first communication device 30 seconds after the wireless device is turned on, and transfers the obtained data to the second communication device.

[0044] As shown in Fig. 3, for 30 seconds after the wireless device is turned on, the wireless device only transmits management frames and does not transmit data, just as in the case of Fig. 2. Therefore, for 30 seconds after the wireless device is turned on, the remaining time decreases. This is because the time used to transmit management frames increases as time passes, and the time used to transmit management frames is subtracted from the 6-second time limit as consumed time.

[0045] Next, from the time when the wireless device starts to obtain data from the first communication device and transmits the data to the second communication device (30 seconds elapsed) until 60 seconds, the rate at which the remaining time decreases becomes large. This is because, as time passes, both the time used to transmit the management frame and the time used to transmit data to the second communication device increase, and both of these times are subtracted as consumed time from the 6-second time limit.

[0046] Next, when the time elapsed since the power was turned on exceeds 60 seconds, the time used to transmit management frames from 60 seconds or more prior to that time is no longer included in the consumed time (in other words, that consumed time is no longer counted as past transmission results). Therefore, the rate at which the remaining time decreases after 60 seconds has elapsed decreases accordingly. However, if the wireless device continues to transmit data to the second communication device, the remaining time will eventually reach 0 seconds, and the wireless device will be unable to communicate with the second communication device.

[0047] In order to avoid such a state in which communication is not possible, conventional wireless devices check past transmission records when transmitting data obtained from a first communication device to a second communication device, and if they determine that transmitting that data to the second communication device would result in a transmission time per hour exceeding a specified time ratio of 10%, they discard the data as mentioned at the beginning (see Figure 1).

[0048] However, as described above, discarding part of the data acquired by the wireless device may, for example, degrade the quality of an application or service that uses communication with the second communication device (for example, causing frame drops in an application that transmits video data, or audio skipping, etc.).

[0049] Therefore, the inventors of the present application, after extensive research, have found that by setting a management unit time shorter than the legally prescribed one hour and estimating the time available for the wireless device to transmit new data to the second communication device in the next management unit time so as not to exceed the time limit (predetermined time ratio) based on the wireless device's transmission record in the most recent management unit time, it is possible to limit the amount of data that the wireless device acquires from the first communication device according to the communication band available for transmitting new data to the second communication device. This makes it possible to provide a wireless device that can perform appropriate communication control in response to changes in the wireless environment.

[0050] Hereinafter, the embodiment will be specifically described with reference to the drawings.

[0051] The embodiments described below each show a preferred specific example of the present invention. The numerical values, shapes, materials, components, the arrangement and connection of the components, steps, and the order of steps shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, among the components in the following embodiments, those components that are not described in the independent claims showing the highest concept of the present invention are described as any components that constitute a more preferred embodiment. Note that the same components are given the same reference numerals and descriptions may be omitted.

[0052] (Embodiment) In this embodiment, a communication system and a wireless device capable of performing appropriate communication control in response to changes in the wireless environment will be described.

[0053] [1. Configuration] First, a configuration of a communication system including a wireless device according to the present embodiment will be described. Fig. 4 is a schematic diagram showing an example of the configuration of a communication system including a wireless device according to the present embodiment.

[0054] In the present embodiment, the communication system 1 includes, for example, a wireless device 10, a first communication device 21, and a second communication device 22. In Fig. 4, the communication system 1 includes one each of the first communication device 21 and the second communication device 22, but may include two or more of them.

[0055] The wireless device 10 transmits data acquired from the first communication device 21 to the second communication device 22 using a predetermined communication standard. The predetermined communication standard limits the wireless transmission time per unit time. For example, the predetermined communication standard is IEEE802.11ah. According to the above-mentioned rules, the wireless device 10 needs to control communication so that the wireless transmission time using 802.11ah does not exceed 360 seconds per hour (i.e., 3600 seconds).

[0056] In this embodiment, wireless device 10 acquires the time used for transmitting data to second communication device 22 from the transmission record with second communication device 22 in a first period having the above-mentioned management unit time width (e.g., 60 seconds) and ending at the current time, estimates the time available for transmitting new data to second communication device 22 in a second period having the above-mentioned management unit time width and starting at the current time, and multiplies the estimated time by the data rate to calculate the communication bandwidth available for transmitting new data to second communication device 22. However, the lengths of the first period and the second period do not need to be the same.

[0057] Furthermore, the wireless device 10, in accordance with the calculated communication band, (i) limits the communication speed of new data acquired from the first communication device 21 in the second period starting from the current time, or (ii) limits the communication speed of new data transmitted from the first communication device 21 to the wireless device 10 in the second period starting from the current time. This contributes to preventing data from being accumulated in the wireless device 10 (in other words, preventing the wireless device 10 from continuing to hold received data without being able to transmit it).

[0058] The wireless device 10 includes, for example, a first communication unit 11, a second communication unit 12, a control unit 13, and a storage unit 14.

[0059] The first communication unit 11 is a communication circuit (or a communication module) that communicates with the first communication device 21. The first communication unit 11 may include, for example, at least one of a communication circuit for communicating via a wide area communication network and a communication circuit for communicating via a local communication network. The first communication unit 11 may be a wired communication circuit for performing wired communication, or a wireless communication circuit for performing wireless communication. The communication standard of the first communication unit 11 is not particularly limited.

[0060] The second communication unit 12 is a communication circuit (or a communication module) that performs wireless communication with the second communication device 22 according to the above-mentioned predetermined communication standard (for example, IEEE802.11ah).

[0061] The control unit 13 performs various information processing related to the wireless device 10. The control unit 13 is realized by, for example, a microcomputer, but may also be realized by a processor or a dedicated circuit. The functions of the control unit 13 are realized by hardware such as a microcomputer or a processor constituting the control unit 13 executing a computer program (so-called software) stored in the storage unit 14.

[0062] The control unit 13 includes an acquisition unit 131, an estimation unit 132, a calculation unit 133, and a band limiting unit 134 as functional components. Specific processes performed by the acquisition unit 131, the estimation unit 132, the calculation unit 133, and the band limiting unit 134 will be described later. The control unit 13 performs duty control (control based on the ratio (proportion) of the transmittable time within the management unit time) using a management unit time shorter than the unit time (here, 1 hour). The management unit time is, for example, 60 seconds, but is not limited to this, and may be appropriately set according to the design. The management unit time is used as the time length of a first period ending at the current time, and the time length of a second period starting at the current time. In the following description, a case in which the time lengths of the first period and the second period are equal will be mainly described, but the first period and the second period may each have a different time length.

[0063] The storage unit 14 is a storage device that stores computer programs executed by the control unit 13. The storage unit 14 can also temporarily store information that needs to be stored due to information processing performed by the first communication unit 11, the second communication unit 12, and the control unit 13. The storage unit 14 is realized by, for example, an HDD (Hard Disk Drive), but may also be realized by a semiconductor memory.

[0064] The first communication device 21 transmits data to the second communication device 22 via the wireless device 10. For example, the first communication device 21 transmits data to the wireless device 10 in response to a request from the second communication device 22 obtained via the wireless device 10. At this time, the first communication device 21 transmits identification information of the second communication device 22 together with the data.

[0065] The first communication device 21 may adjust the communication speed of data that the first communication device 21 transmits to the wireless device 10 in accordance with a control signal output from the band limiting unit 134 of the wireless device 10, for example.

[0066] Incidentally, since the communication between the first communication device 21 and the wireless device 10 has been explained in the first communication unit 11, the explanation thereof will be omitted here.

[0067] The wireless device 10 may be, for example, an access point (wireless access point) equipped with a wireless communication circuit, or a relay device (bridge device) that relays wired communication and wireless communication between each other.

[0068] The first communication device 21 may be, for example, a Web server, an edge server, or a sensor. The sensor may be, for example, a camera, a microphone, or a thermal image sensor, but is not limited thereto.

[0069] The second communication device 22 acquires data transmitted in accordance with a predetermined communication standard (IEEE802.11ah) from the wireless device 10. The second communication device 22 is, for example, an information terminal such as a stationary or portable computer device, a tablet terminal, or a smartphone.

[0070] [2. Operation] Next, the operation of the wireless device 10 according to the present embodiment will be described. Fig. 5 is a flow diagram showing an example of a process executed by the wireless device 10 according to the embodiment. Fig. 6 is a schematic diagram for explaining an example of the operation of the band limiting unit 134 in the band limiting step S4.

[0071] 5, in acquisition step S1, acquisition unit 131 of wireless device 10 acquires the time used by wireless device 10 to transmit data to second communication device 22 during a first period (e.g., the most recent 60 seconds) ending at the current time. For example, acquisition unit 131 may refer to the communication history stored in storage unit 14 and calculate the time used by second communication unit 12 to transmit data to second communication device 22 during the first period from the transmission record during the first period, or may read out the time from storage unit 14.

[0072] In the acquisition step S1, the acquisition unit 131 may further acquire, for example, the time used in transmitting the management frame during the first period. For example, the acquisition unit 131 may refer to the communication history stored in the storage unit 14 and calculate the time used by the second communication unit 12 in transmitting the management frame to the second communication device 22 from the transmission record during the first period, or may read out the predetermined time from the storage unit 14. Note that since the wireless device 10 always transmits a constant amount of management frames at the slowest data rate, the time used in transmitting the management frames does not change during the first period and the second period, and therefore a predetermined fixed value may be used.

[0073] Next, in an estimation step S2, the estimation unit 132 of the wireless device 10 estimates the time available for the wireless device 10 to transmit new data to the second communication device 22 in the second period, using the time used for transmitting data to the second communication device 22 in the first period acquired in the acquisition step S1 and the time used for management frames in a second period (e.g., the next 60 seconds) starting from the current time, so that the total sum of wireless transmission times in the time slots relative to the total time of the first period and the second period does not exceed a predetermined time ratio (i.e., 10% in 802.11ah communication). For example, when the first period and the second period have the same period length of 60 seconds, the estimation unit 132 of the wireless device 10 can estimate the time available for the wireless device 10 to transmit new data to the second communication device 22 in the second period, so that the total sum of the wireless transmission time in the first period and the wireless transmission time in the second period is equal to or less than twice 6 seconds. In this way, even if radio transmission occurs in a first period that exceeds a specified time ratio, it can be suppressed by that amount in the following second period, and conversely, if radio transmission occurs in the first period that falls below the specified time ratio, the surplus amount can be accumulated in the following second period to consume time for radio transmission, thereby enabling flexible operational management of transmission.

[0074] Next, in calculation step S3, calculation unit 133 of wireless device 10 calculates the communication bandwidth available for wireless device 10 to transmit new data to second communication device 22 during the second period by multiplying the time available for wireless device 10 to transmit new data to second communication device 22 during the second period, estimated in estimation step S2, by the data rate at the current time and further dividing the result by the length of the second period (60 seconds in this example).

[0075] Next, in a band limiting step S4, the band limiting unit 134 limits the band that the wireless device 10 transmits to the second communication device 22 during the second period according to the communication band calculated in the calculation step S3. At this time, if the band that the wireless device 10 transmits to the second communication device 22 is limited, data retention may occur in the wireless device 10 depending on the amount of data received from the first communication device 21, and if the retained data exceeds the buffer capacity, relaying may fail. Therefore, the wireless device 10 limits the communication speed of new data acquired from the first communication device 21. For example, as shown in FIG. 6, the band limiting unit 134 limits the communication band that the first communication unit 11 can use for communication with the first communication device 21. This depends on the communication protocol between the wireless device 10 and the first communication device 21, but it can be achieved by controlling, for example, the timing of the wireless device 10 sending an Ack signal accompanying data reception, or the timing of the wireless device 10 sending a data transmission request, or the like. Of course, as described later, control information may be transmitted to the first communication device 21 to limit transmission.

[0076] When the processing of the band limiting step S4 ends and a fixed period (for example, 2 seconds) has elapsed, the processing returns to the acquisition step S1 again. Note that the processing of step S1 may be returned to at each timing of transmitting data to the second communication device 22, instead of at a fixed period.

[0077] In this way, by repeatedly executing a series of processes (steps S1 to S4), wireless device 10 can control communications so that the total transmission time per unit time from the start of radio wave transmission does not exceed a predetermined time ratio per unit time.

[0078] Needless to say, the communication bandwidth value calculated in step S3 is not necessarily applied as a fixed value during the second period, but is replaced with a newly calculated value if the process returns to step S3 again from step S4 via steps S1 and S2 during the second period.

[0079] [Specific example of estimation process] Next, the estimation process performed by the wireless device 10 in the estimation step S2 will be described in more detail. FIG. 7 is a first diagram for specifically explaining the estimation process performed by the wireless device 10 according to the embodiment. FIG. 8 is a second diagram for specifically explaining the estimation process performed by the wireless device 10 according to the embodiment. FIG. 9 is a third diagram for specifically explaining the estimation process performed by the wireless device 10 according to the embodiment. FIG. 10 is a fourth diagram for specifically explaining the estimation process performed by the wireless device 10 according to the embodiment. Note that, in this example, the communication standard between the wireless device 10 and the second communication device 22 is IEEE802.11ah. In IEEE802.11ah, the wireless transmission time per unit time (1 hour = 3,600 seconds) is limited to 1 / 10 of that, that is, 360 seconds.

[0080] In Figs. 7 to 10, the horizontal axis of the graph indicates time (seconds) when the power of the wireless device 10 is turned on as time 0. The vertical axis of the graph indicates the remaining time as a percentage when the total time (6 seconds in this example) during which the wireless device 10 can transmit radio waves in the 920 MHz band in the management unit time (60 seconds in this example) is set to 100%. The percentage of the remaining time is a value obtained by subtracting the time used by the wireless device 10 to transmit radio waves in the 920 MHz band from the total time (6 seconds) during which the wireless device 10 can transmit radio waves in the management unit time (60 seconds) and dividing the result by the total time during which the wireless device 10 can transmit the radio waves (6 seconds). In the drawings, the control frame A1 is a control frame indicating a first period (60 seconds in this example) ending at the current time, and the control frame A2 is a control frame indicating a second period (60 seconds in this example) starting at the current time. The height of the control frame in the vertical axis direction is 100% (that is, equivalent to 6 seconds).

[0081] 7 to 10 show the percentage of time used by management frame transmission. Dotted vertical bars show the percentage of time used by past data transmission, and dashed vertical bars show the percentage of time used by data transmission from the present onwards. The management frame will be explained on the premise that a beacon frame is transmitted for 3.3 milliseconds every 100 milliseconds as mentioned above (i.e., 2 seconds of transmission time is consumed in 60 seconds).

[0082] FIG. 7 illustrates an example of a process executed by the wireless device 10 when the wireless device 10 is powered on.

[0083] When the wireless device 10 is powered on, the acquisition unit 131 of the wireless device 10, for example, refers to the communication history in the control frame A1 stored in the storage unit 14, and acquires the time (here, zero seconds) that the wireless device 10 used to transmit data to the second communication device 22 during the first period. The acquisition unit 131 also acquires the time (here, zero seconds) that the wireless device 10 used to transmit a management frame during the first period.

[0084] Next, the estimation unit 132 of the wireless device 10 uses the time (zero seconds) used to transmit data to the second communication device 22 during the first period acquired by the acquisition unit 131 and the time T1 used for the management frame during the second period to estimate the time T2 that the wireless device 10 can use to transmit new data to the second communication device 22 during the second period such that the sum of the wireless transmission time during the first period and the wireless transmission time during the second period does not exceed 12 seconds (in this example, the time obtained by multiplying the total time of the first and second periods, that is 120 seconds, by a predetermined time ratio of 10%).

[0085] The time during which wireless device 10 can transmit radio waves in the 920 MHz band (6 seconds in this example) is a time equivalent to 10% of the management unit time (60 seconds in this example). Here, the time available for wireless device 10 to transmit new data to second communication device 22 in the second period is the remaining time (6-2=4 seconds) obtained by subtracting the time used for transmitting management frames (2 seconds) from the transmittable time of wireless device 10 in the second period (60 seconds) (6 seconds). Furthermore, since no transmission was performed at all in the past first period, the 10 seconds obtained by adding the surplus communicable time of this period, which is 6 seconds, is considered to be the available period for data transmission in the second period.

[0086] In this case, if 10 seconds is expressed as the ratio of time T2 to the time during which wireless device 10 can transmit radio waves in the 920 MHz band, then 10 seconds / 6 seconds×100≈167%, which corresponds to the upper end position of T2 in the graph in FIG.

[0087] Next, with reference to FIG. 8, an example of processing executed by the wireless device 10 when 30 seconds have elapsed since the wireless device 10 was powered on will be described.

[0088] The acquisition unit 131 of the wireless device 10 refers to the communication history in the control frame A1 stored in the storage unit 14, and acquires the time (here, zero seconds) that the wireless device 10 used to transmit data to the second communication device 22 during the first period. The acquisition unit 131 also acquires the time T1 (2 seconds) that the wireless device 10 used to transmit a management frame during the first period.

[0089] Next, the estimation unit 132 of the wireless device 10 estimates the time T2 that the wireless device 10 can use to transmit new data to the second communication device 22 in the second period, using the time acquired by the acquisition unit 131 to transmit data to the second communication device 22 in the first period (no data was transmitted for 30 seconds from the time the power was turned on, so that this is zero seconds) and the time T1 used for the management frame for the total of 120 seconds that is the first and second periods (2 seconds per 60 seconds, so that the total of the first and second periods is 3 seconds), so that the total of the wireless transmission time in the first period and the wireless transmission time in the second period does not exceed 12 seconds (the total of the first and second periods, 120 seconds, multiplied by a predetermined time ratio of 10%). In the example of FIG. 8, the time used to transmit data to the second communication device 22 in the first period is also zero seconds, so the time T2 that the wireless device 10 can use to transmit new data to the second communication device 22 is 6×2−3=9 seconds. This corresponds to 9 / 6=150% in the length of the dashed line in FIG. 8.

[0090] In the second period, the time T2 available for data transmission can be more generally expressed as follows: T2 = duration of period × 2 × α-Tm-Td This can be expressed as:

[0091] Here, T2 is the time available for data transmission in the second period, α is a predetermined time ratio, which is 10% in the 802.11ah standard, Tm is the management frame transmission time (the sum of the first period and the second period), and Td is the time used for data transmission in the first period.

[0092] The above formula is for the case where the first period length is equal to the second period length. If the two are different, T2 = (t1 + t2) × α - Tm - Td Here, t1 is the length of the first period, and t2 is the length of the second period.

[0093] Once the time T2 available for data transmission in the second period has been estimated in this manner, T2 is then multiplied by the data rate to calculate the amount of data that can be transmitted in the second period, and this is then divided by the length of the second period, which is 60 seconds, to obtain the transmission bandwidth for that period (in other words, the maximum bandwidth that can be transmitted).

[0094] That is Transmission bandwidth (bps) = available time (sec) x data rate (bit / sec) / period length (sec) This is expressed as:

[0095] 9 will further explain an example of processing executed by the wireless device 10 when 60 seconds have elapsed since the wireless device 10 was powered on. In FIG. 9, the wireless device 10 starts transmitting data to the second communication device 22 30 seconds after the power was turned on.

[0096] The acquisition unit 131 of the wireless device 10 acquires the time T3 that the wireless device 10 used to transmit data to the second communication device 22 during the first period (0 seconds to 60 seconds). At this time, the acquisition unit 131 also acquires the time T1 that the wireless device 10 used to transmit management frames during the first period.

[0097] Next, the estimation unit 132 of the wireless device 10 estimates a time T21 that the wireless device 10 can use to transmit new data to the second communication device 22 in the second period, using the time T3 used to transmit data to the second communication device 22 in the first period acquired by the acquisition unit 131 and the time T1×2 used to transmit management frames in the first period and the second period (0 to 120 seconds), so that the sum of the wireless transmission time in the first period and the wireless transmission time in the second period does not exceed 12 seconds (the time obtained by multiplying the total time of the first period and the second period, 120 seconds, by a predetermined time ratio of 10%). Specifically, T21=6×2-2×2-T3, but it is also possible to consider that the estimation unit 132 can add the surplus band B1 that was not used during the period (0 to 30 seconds) in which data was not transmitted to the second communication device 22 in the first period as the band B2 that can be used in the next management unit time (i.e., the second period). As in the example shown in Figure 9, in the case where 100% transmission, including management frames, has occurred from 30 seconds in the past to the present, T3 = 2 seconds, and according to the above formula, T21 = 6 seconds, so the height of the dashed line in the figure is 100% (if the 2 seconds for management frames are included, it becomes (6 + 2) / 6 x 100 = 133%).

[0098] FIG. 10 illustrates an example of processing that the wireless device 10 executes when 90 seconds have passed since the wireless device 10 was powered on.

[0099] The acquisition unit 131 of the wireless device 10 acquires the time T3 that the wireless device 10 used to transmit data to the second communication device 22 during the first period (30 seconds to 90 seconds). At this time, the acquisition unit 131 also acquires the time T1 that the wireless device 10 used to transmit management frames during the first period.

[0100] Next, the estimation unit 132 of the wireless device 10 estimates a time T22 that the wireless device 10 can use to transmit new data to the second communication device 22 in the second period, using the time T3 used to transmit data to the second communication device 22 in the first period acquired by the acquisition unit 131 and the time T1 used for the management frame in the first period and the second period (30 seconds to 150 seconds), so that the sum of the wireless transmission time in the first period and the wireless transmission time in the second period does not exceed 12 seconds (the total time of the first and second periods, 120 seconds, multiplied by a predetermined time ratio of 10%). Specifically, using the same calculation formula as that described in FIG. T22=6×2-2×2-T3 However, for example, if the time (6 seconds) during which wireless device 10 can transmit radio waves in the first period is used 100%, including the management frame, estimation unit 132 can estimate that the time T22 during which wireless device 10 can transmit new data to second communication device 22 in the second period is the same as time T3. (When T3=4 seconds in the above formula, the actual transmission time during the first period is 6 seconds, but when substituted into the above formula, T22 also becomes 4 seconds, and as shown in FIG. 10, including the 2 seconds for the management frame, the graph becomes 6 seconds, that is, 100% high.)

[0101] Thereafter, the transmission bandwidth for the second period (90 seconds to 150 seconds) is calculated using the same procedure as that described with reference to FIG.

[0102] In the above example, in the band limiting step S4, the band limiting unit 134 of the wireless device 10 limits the communication speed of the data that the wireless device 10 acquires from the first communication unit 11 in accordance with the communication band calculated in the calculation step S3, but this is not limited to the example. For example, as shown in Fig. 11, the band limiting unit 134 of the wireless device 10 may limit the communication speed of the data that the first communication device 21 transmits to the wireless device 10 in accordance with the communication band calculated in the calculation step S3.

[0103] 11 is a schematic diagram for explaining another example of the operation of the band limiting unit 134 in the band limiting step S4. First, for example, the band limiting unit 134 outputs to the first communication unit 11 the control information including the communication band that the wireless device 10 can use for transmission to the second communication device 22, calculated in the calculation step S3, and an instruction to cause the first communication device 21 to limit the transmission speed of data to be transmitted to the wireless device 10 according to the communication band. Here, the instruction included in the control information may include, for example, the transmission speed of data to be transmitted to the wireless device 10, calculated by the band limiting unit 134 of the wireless device 10. The data transmission speed may be calculated according to a priority in communication band usage that is preset between the communication band that the wireless device 10 can use for transmission to the second communication device 22, among the communication bands calculated in the calculation step S3. Specifically, the data transmission speed may be determined according to a preset allocation ratio (for example, 80:20) between the communication band that the wireless device 10 can use for transmission to the second communication device 22 and the data transmission speed. Next, when the first communication unit 11 acquires the control information output from the band limiting unit 134, it transmits the control information to the first communication device 21. The first communication device 21 determines the transmission speed of data to be transmitted to the wireless device 10 based on an instruction included in the control information transmitted from the wireless device 10.

[0104] As described above, in the embodiment of the present invention, the wireless device 10 acquires the time used for data transmission to the second communication device 22 in a first period ending at the current time from the transmission record with the second communication device 22 in the first period, estimates the time available for transmitting new data to the second communication device 22 in the next control period (more specifically, the second period starting at the current time) so that the sum of the wireless transmission times in the first and second periods does not exceed a predetermined time ratio to the total time of the first and second periods, and calculates the communication band available for transmitting new data to the second communication device 22 by multiplying the estimated time by the data rate. In this way, even if the data rate varies depending on the state of wireless communication, the wireless device 10 can calculate the communication band available for communication with the second communication device 22 in accordance with the variation in the data rate. Therefore, the wireless device 10 can perform appropriate communication control in accordance with the change in the wireless environment.

[0105] Moreover, in the embodiment of the present invention, the wireless device 10 further (i) limits the communication speed of new data acquired from the first communication device 21 in the second time period, or (ii) limits the communication speed of new data transmitted from the first communication device 21 to the wireless device 10 in the second time period, according to the calculated communication band. By the above (i), the wireless device 10 can limit the amount of new data acquired from the first communication device 21 to an amount that can be transmitted within a time available for transmission to the second communication device 22. By the above (ii), the wireless device 10 can limit the amount of new data transmitted from the first communication device 21 to an amount that can be transmitted within a time available for transmission to the second communication device 22. By the above (i) or (ii), the wireless device 10 can appropriately control communication in response to a change in the wireless environment in the communication system 1.

[0106] In the above embodiment, the wireless device 10 and the first communication device 21 are separate devices, but the present invention is not limited to this example. For example, the wireless device 10 may include the first communication device 21. These two devices may have the same housing, and may be arranged on the same board. For example, the first communication device 21 may be attached to the housing of the wireless device 10. For example, when the first communication unit 11 of the wireless device 10 transmits and receives data to and from the first communication device 21, the communication may be performed via communication or without communication. For example, when the first communication device 21 is attached to the housing of the wireless device 10, the first communication unit 11 of the wireless device 10 may transmit and receive data to and from the first communication device 21 via wired communication or wireless communication. For example, when the first communication device 21 is built into the housing of the wireless device 10, the first communication unit 11 is connected to the first communication device 21 via an internal bus.

[0107] 12 is a schematic diagram for explaining an example of the operation of the band limiting unit 134 in the case where the first communication device 21 is integrated with the wireless device 10 and the wireless device 10 includes the first communication device 21. For example, as shown in FIG. 12, the band limiting unit 134 of the wireless device 10 outputs to the first communication unit 11 control information including the communication band that the wireless device 10 can use to transmit new data to the second communication device 22, calculated in the calculation step S3, and an instruction to cause the first communication device 21 to control the transmission speed of the new data to be transmitted to the wireless device 10 according to the communication band. Next, the first communication unit 11 transmits the control information acquired from the band limiting unit 134 to the first communication device 21. Note that the control information does not necessarily have to include the above instruction. Note that the control information includes identification information of the wireless device 10 and the second communication device 22.

[0108] In the above embodiment, even if the wireless data rate with the second communication device 22 dynamically changes depending on the error occurrence rate, the wireless device 10 calculates the bandwidth available for transmitting new data to the second communication device 22 using the data rate at the current time, and therefore can perform appropriate communication control in response to changes in the wireless environment. However, the data rate used to calculate the bandwidth available for the second communication device 22 may be fixed to a value lower than normal. This allows the wireless device 10 to perform stable data communication regardless of the wireless environment.

[0109] When the wireless device 10 transmits new data to a plurality of second communication devices 22, the bandwidth available for transmitting the new data may be further limited, for example, to 10% to 5%, depending on the number of second communication devices 22. This makes it possible to increase the number of second communication devices 22 that can simultaneously communicate in the same frequency band (for example, the 920 MHz band).

[0110] (Application Example of the Embodiment) Here, for example, a technique is known in which a compression rate of a moving image is determined and transmitted after measuring an available communication band before transmitting the moving image. In a communication system using such a conventional technique, a communication device (e.g., a communication device on the content provider side) that transmits the moving image unilaterally determines the compression rate of the moving image and distributes the moving image. Therefore, if the communication environment deteriorates after that, the quality of the moving image received by a communication device on the receiving side (e.g., a communication device of a content viewer) may deteriorate significantly. Therefore, viewers may feel uncomfortable each time the compression rate of the communication device on the transmitting side changes. In addition, when a moving image is distributed using a communication standard (e.g., 802.11ah, etc.) that is limited in the total transmission time per unit time as described above, when the upper limit of the time limit is reached, the distribution stops and the moving image cannot be distributed until the communication is restored (the time when the communication is available is guaranteed). The wireless device according to the embodiment of the present invention can be applied to such a problem.

[0111] An example of an application of the embodiment of the present invention is a communication system (also called a video distribution system) that distributes video from a content server to a plurality of communication terminals connected via a network.

[0112] The configuration of a video delivery system including a wireless device according to an application example of the embodiment of the present invention will be described below. Fig. 13 is a schematic diagram showing an example of the configuration of a video delivery system including a wireless device according to the embodiment of the present invention.

[0113] In the application example of this embodiment shown in Fig. 13, the video distribution system 1000 includes, for example, a wireless device 100, a distribution server 301 (corresponding to the first communication device 21 in the embodiment of the present invention), a communication terminal 201 (corresponding to the second communication device 22 in the embodiment of the present invention), a communication terminal 202 (corresponding to the other second communication device 22 in the embodiment of the present invention), a communication link 303, and a wireless link 304. Note that, although Fig. 13 shows an example in which the video distribution system 1000 includes two communication terminals, the communication terminal 201 and the communication terminal 202, it may include three or more communication terminals.

[0114] The distribution server 301 performs a compression process on the video data, and transmits the compressed video data to the wireless device 100 .

[0115] The wireless device 100 sets a compression rate for the compression process of the distribution server 301 in the second period according to the communication band calculated by the calculation unit 133 , and transmits the set compression rate to the distribution server 301 .

[0116] Specifically, in the process of receiving video data from distribution server 301, wireless device 100 according to the application example of the embodiment of the present invention calculates a transmission band through the steps shown in FIG. 5 described above, and then transmits the obtained control information to distribution server 301. Based on the control information, distribution server 301 can dynamically change the compression rate of video data to be distributed. More specifically, distribution server 301 can dynamically change the compression process during video encoding or audio encoding, and transmits video data by performing video encoding or audio encoding using the changed compression process. Based on the control information received from wireless device 100, distribution server 301 generates video data to be transmitted to communication terminals 201 and 202 so as to comply with the transmission time limit from wireless device 100 to the communication terminals.

[0117] When the distribution server 301 transmits video data to the communication terminals 201 and 202 via the wireless link 304, the transmission time of the video data from the wireless device 100 to the communication terminals 201 and 202 via the wireless link 304 is automatically controlled based on the amount of data received from the distribution server 301.

[0118] This is because the video data distributed from the distribution server 301 is generated in advance by compressing it at an appropriate compression rate based on the control information received from the wireless device 100, and the amount of data itself is an appropriate amount of data that can be communicated via the wireless link 304.

[0119] In this manner, the wireless device 100 according to the application example of the embodiment of the present invention can perform appropriate communication control in response to changes in the wireless environment.

[0120] The present invention can be realized not only as an apparatus, but also as a method in which the processing means constituting the apparatus are steps, as a program for causing a computer to execute those steps, as a computer-readable recording medium such as a CD-ROM on which the program is recorded, or as information, data or signals indicating the program.These programs, information, data and signals may be distributed via a communication network such as the Internet.

[0121] Although the wireless device, the control method and the program of the present invention have been described based on the embodiment, the present invention is not limited to this embodiment. As long as it does not deviate from the spirit of the present invention, various modifications conceived by those skilled in the art to the present embodiment and forms constructed by combining components of different embodiments are also included within the scope of the present invention. [Industrial Applicability]

[0122] The present invention can be used in wireless devices and the like that can perform appropriate communication control in response to changes in the wireless environment. [Explanation of symbols]

[0123] 1. Communication Systems 10, 100 wireless devices 11 First Communications Department 12 Second Communications Department 13 Control section 131 Acquisition Department 132 Estimation Department 133 Calculation section 134 Bandwidth Limiting Section 14 Storage section 21 First communication device 22 Second communication device 201, 202 Communication terminal 301 Distribution Server 303 Communication Links 304 Wireless Link 1000 Video distribution system A1, A2 control frame B1, B2 band

Claims

1. A wireless device that transmits data acquired from a first communication device to a second communication device in accordance with a predetermined communication standard, the predetermined communication standard limits the wireless transmission available time per unit time to a predetermined time ratio or less, The wireless device includes: an acquisition unit that acquires a time used by the wireless device to transmit the data to the second communication device and a time used by the wireless device to transmit a management frame during a first period ending at a current time; an estimation unit that estimates a time that the wireless device can use to transmit new data to the second communication device in the second period, using a time used to transmit the data, a time used to transmit the management frame, and a time used to transmit a management frame in a second period starting from a current time, such that a sum of a wireless transmission time in the first period and a wireless transmission time in the second period does not exceed the predetermined time ratio with respect to a total time of the first period and the second period; a calculation unit that calculates a communication bandwidth available for the wireless device to transmit the new data to the second communication device during the second period by multiplying a time available for transmitting the new data by a data rate that is a communication speed between the wireless device and the second communication device; Equipped with Radio equipment.

2. further comprising a band limiting unit that limits a communication speed of data that the wireless device acquires from the first communication device during the second period in accordance with the communication band calculated by the calculation unit.

2. The wireless device of claim 1.

3. further comprising a band limiting unit configured to transmit to the first communication device control information including an instruction to limit a communication rate of the new data transmitted by the first communication device to the wireless device during the second period in accordance with the communication band calculated by the calculation unit.

2. The wireless device of claim 1.

4. The first period and the second period have the same time length. The wireless device according to any one of claims 1 to 3.

5. the wireless device includes the first communication device; The wireless device according to any one of claims 1 to 3.

6. The predetermined communication standard is IEEE 802.11ah. The wireless device according to any one of claims 1 to 3.

7. 1. A communication system comprising: A wireless communication device according to claim 1 and the first communication device, The first communication device performs a compression process on the moving image data and transmits the compressed moving image data as the data; The wireless device sets a compression ratio in the compression process of the first communication device during the second period in accordance with the communication band calculated by the calculation unit, and transmits the set compression ratio to the first communication device. Communication systems.

8. A method for controlling a wireless device that transmits data acquired from a first communication device to a second communication device using a predetermined communication standard, comprising: the predetermined communication standard limits the wireless transmission available time per unit time to a predetermined time ratio or less, The wireless device includes: an acquisition step of acquiring a time used by the wireless device to transmit the data to the second communication device and a time used by the wireless device to transmit a management frame during a first period ending at a current time; an estimation step of estimating a time available for the wireless device to transmit new data to the second communication device in the second period, using a time used for transmitting the data, a time used for transmitting the management frame, and a time used for transmitting a management frame in a second period starting from a current time, such that a sum of a wireless transmission time in the first period and a wireless transmission time in the second period does not exceed the predetermined time ratio with respect to a sum time of the first period and the second period; a calculation step of multiplying a time available for transmitting the new data by a data rate that is a communication speed between the wireless device and the second communication device to calculate a communication bandwidth available for the wireless device to transmit the new data to the second communication device during the second period; Including, A method for controlling a wireless device.

9. A program for causing one or more computers to execute the method for controlling a wireless device according to claim 8.

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