JP5445401B2 - COMMUNICATION DEVICE, COMMUNICATION METHOD, AND COMMUNICATION PROGRAM - Google Patents

Description

  The present invention relates to a communication device, a communication method, and a communication program. More specifically, the present invention relates to a communication device, a communication method, and a communication program that can measure a usable bandwidth in a communication path between communication devices.

  2. Description of the Related Art Communication apparatuses capable of continuously measuring usable transmission path capacity in a communication network (such as the Internet) in which the communication environment varies are known. Hereinafter, “transmission path capacity” is also referred to as “bandwidth”. Usable transmission line capacity is called “usable bandwidth”. For example, in the communication device described in Non-Patent Document 1, a communication device (hereinafter referred to as “transmission device”) that transmits a measurement packet (hereinafter referred to as “measurement packet”) calculates a transmission interval of measurement packets. Time information to be stored in the measurement packet. The transmission device continuously transmits a plurality of measurement packets while changing a transmission band (hereinafter referred to as “measurement band”) by gradually changing a transmission interval. A communication device on the receiving side (hereinafter referred to as “receiving device”) stores a packet reception interval. Thereafter, a difference between the transmission interval included in the time information in the packet and the reception interval stored in the receiving device is calculated. The usable bandwidth is specified from the change tendency of the calculated difference values. The identified usable bandwidth is notified to the transmission device. The transmission device can acquire the usable bandwidth.

  Data desired by the user (audio data, video data, etc., hereinafter referred to as “desired data”) may be stored in the measurement packet. As a result, the communication device can perform communication of desired data between the communication devices while measuring the usable bandwidth of the communication path. Therefore, communication of the desired data can be performed efficiently.

Implementation and performance evaluation of inline network measurement method ImTCP and its application method Tomoaki Tsukawa, LE THANH MAN, Cao, Go Hasegawa, Masayuki Murata IEICE Technical Report (IN2005-120), pp. 79-84, December 2005

  In the above-described method, the transmission interval of measurement packets transmitted from the transmission device becomes longer as the measurement band moves to the narrow band side. In this case, a situation occurs in which the measurement packet does not reach the receiving device for a long time, and communication delay increases. Therefore, when desired data requiring real-time property is stored in the measurement packet, there is a problem that communication quality may be greatly deteriorated due to communication delay.

  An object of the present invention is to provide a communication device, a communication method, and a communication program that can measure the usable bandwidth of a communication path while maintaining good communication quality.

The communication device according to the first aspect of the present invention provides a measurement band by sequentially changing a transmission interval of a measurement packet group including one or more measurement packets with respect to a counterpart device that is another communication device connected to a network. Is a communication device that measures an available bandwidth that is a usable bandwidth in the network, the first specifying means for specifying the measurement band, and the specified by the first specifying means First determination means for determining the data size of the measurement packet group based on the measurement band, and the transmission interval of the measurement packet group based on the data size and the measurement band determined by the first determination means A second determination unit that determines the data size determined by the first determination unit; a generation unit that generates the measurement packet group having the data size determined by the first determination unit; The measurement packet group created by the creation means, transmitting means for transmitting to said partner apparatus by being determined the transmission interval by the second determining means is stored in the measurement packets constituting the measurement packet group Second specifying means for specifying the type of data to be determined, wherein the first determining means determines the data size based on the type specified by the second specifying means .

According to the first aspect, the data size of the measurement packet group is determined based on the measurement band. The transmission interval is uniquely determined from the data size and the measurement band. Accordingly, by appropriately determining the data size of the measurement packet group according to the measurement band, it is possible to prevent the transmission interval when the measurement packet group is transmitted from becoming extremely long. The communication device can avoid a state in which desired data stored in measurement packets constituting the measurement packet group does not reach the counterpart device for a long time. Therefore, the communication apparatus can measure the usable bandwidth while preventing the occurrence of communication delay and maintaining good communication quality. The data size is determined based on the data type. When the type of desired data that requires real-time performance is specified, the data size can be determined so that the transmission interval becomes shorter. Therefore, the communication device can measure the usable bandwidth while ensuring the communication quality required for the desired data.

  Further, in the first aspect, an encoder that outputs data stored in the measurement packet as a data block of a predetermined size is provided, and the creation unit converts the data block of the predetermined size output from the encoder into the measurement packet. A third specifying unit configured to create the measurement packet group and specify the predetermined size by storing in the measurement packet constituting the group, and the first determining unit is further specified by the third specifying unit. The data size may be determined to be larger than the predetermined size. The data size is determined based on the size (predetermined size) of the data block output from the encoder. Therefore, it is possible to prevent the data block output from the encoder from being assigned to a plurality of measurement packet groups. Since the data block can be packetized without delay, the communication device can quickly transmit the encoded data to the partner device.

  Further, in the first aspect, it comprises second storage means for storing the measurement band and the data size in association with each other, the first determination means refers to the information stored in the second storage means, The data size associated with the measurement band specified by the first specifying unit may be determined as the data size of the measurement packet group. As a result, the communication apparatus can uniquely determine the data size from the measurement band, so that the data size can be determined quickly and accurately.

The communication method according to the second aspect of the present invention provides a measurement band by sequentially changing a transmission interval of a measurement packet group including one or more measurement packets with respect to a counterpart device that is another communication device connected to a network. A communication method executed in a communication device that measures an available bandwidth that is a usable bandwidth in the network, the first specifying step of specifying the measurement bandwidth, and the first specification A first determination step of determining a data size of the measurement packet group based on the measurement band specified by the step; and the data size determined by the first determination step for the transmission interval of the measurement packet group And a second determination step for determining based on the measurement band, and the data determined by the first determination step A creation step of creating said measurement packet group size, a transmission step of transmitting the measurement packets that are created by the creation step, to the partner apparatus at the transmission interval determined by the second determining step A second specifying step of specifying a type of data stored in the measurement packet constituting the measurement packet group, wherein the first determining step is based on the type specified by the second specifying step The data size is determined.

According to the second aspect, the data size of the measurement packet group is determined based on the measurement band. The transmission interval is uniquely determined from the data size and the measurement band. Accordingly, by appropriately determining the data size of the measurement packet group according to the measurement band, it is possible to prevent the transmission interval when the measurement packet group is transmitted from becoming extremely long. The communication device can avoid a state in which desired data stored in measurement packets constituting the measurement packet group does not reach the counterpart device for a long time. Therefore, the usable bandwidth can be measured by the communication method while preventing communication delay and maintaining good communication quality. The data size is determined based on the data type. When the type of desired data that requires real-time performance is specified, the data size can be determined so that the transmission interval becomes shorter. Therefore, the communication device can measure the usable bandwidth while ensuring the communication quality required for the desired data.

The communication program according to the third aspect of the present invention provides a measurement band by sequentially changing a transmission interval of a measurement packet group including one or more measurement packets with respect to a counterpart device that is another communication device connected to a network. Is a communication program for measuring an available bandwidth, which is a usable bandwidth in the network, and is specified by the first specifying step for specifying the measurement band and the first specifying step. A first determination step of determining a data size of the measurement packet group based on the measurement band; and the transmission interval of the measurement packet group, the data size and the measurement band determined by the first determination step. A second determination step of determining based on the data size of the data size determined by the first determination step A creation step of creating a serial measurement packets, a transmission step of transmitting the measurement packets that are created by the creation step, with the transmission interval determined by the second determination step to said partner apparatus, said A second specifying step of specifying a type of data stored in the measurement packet constituting the measurement packet group, and the first determining step is based on the type specified by the second specifying step. The data size is determined .

According to the third aspect, the data size of the measurement packet group is determined based on the measurement band. The transmission interval is uniquely determined from the data size and the measurement band. Accordingly, by appropriately determining the data size of the measurement packet group according to the measurement band, it is possible to prevent the transmission interval when the measurement packet group is transmitted from becoming extremely long. The communication device can avoid a state in which desired data stored in measurement packets constituting the measurement packet group does not reach the counterpart device for a long time. Therefore, by causing the computer to execute the communication program, it is possible to measure the usable bandwidth while preventing communication delay and maintaining good communication quality. The data size is determined based on the data type. When the type of desired data that requires real-time performance is specified, the data size can be determined so that the transmission interval becomes shorter. Therefore, the communication device can measure the usable bandwidth while ensuring the communication quality required for the desired data.

1 is a diagram illustrating an outline of a communication system 100 and an electrical configuration of a communication device 1. FIG. It is a figure which shows the relationship between the data size of a measurement packet group, and a transmission interval. It is a figure which shows the relationship between the data size of a measurement packet group, and a transmission interval. It is a figure which shows the 1st relationship table. It is a flowchart which shows a main process. It is a flowchart which shows a determination process. It is a figure which shows the 1st zone | band table 121. FIG. It is a figure which shows the 2nd relationship table. It is a flowchart which shows the determination process in a 1st modification. It is a figure which shows the 2nd zone | band table 122. FIG. It is a flowchart which shows the determination process in a 2nd modification. It is a figure which shows the 3rd zone | band table 123. FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a communication device 1 that is an embodiment of a communication device of the present invention and a communication system 100 including a plurality of communication devices 1 will be described with reference to the drawings. The drawings to be referred to are used for explaining technical features that can be adopted by the present invention. The configuration of the apparatus, the flowcharts of various processes, and the like described in the drawings are not intended to be limited to these, but are merely illustrative examples.

  The communication system 100 will be described. As shown in FIG. 1, the communication system 100 includes at least two communication devices 1. The communication device 1 is connected to another communication device 1 via the network 8. The communication device 1 communicates various data with other communication devices 1.

  The communication system 100 is a video conference system for users at a plurality of bases to hold a video conference. Each communication device 1 transmits and receives video data and audio data to each other, thereby sharing video and audio at a plurality of locations. The communication device 1 may be any device that can execute data communication via the network 8. Specifically, it may be a dedicated video conference terminal arranged at each base for performing a video conference, or may be a personal computer that performs various information processing.

  In the communication system 100, the bandwidth is measured with the communication device 1 of the communication partner, and the usable bandwidth is specified. The usable bandwidth refers to the maximum transmission rate at which the receiving communication device 1 can receive data at a transmission rate substantially equal to the transmission rate of data transmitted by the transmitting communication device 1. When a packet is transmitted at a transmission rate that exceeds the usable bandwidth, packet loss, communication delay, and the like occur. On the other hand, if the transmission rate is too low, the usable bandwidth cannot be fully utilized, and the efficiency is poor. Accordingly, each communication device 1 controls the transmission rate (bandwidth) to be used in accordance with the specified usable bandwidth. Note that “bps” is used as a unit of the band in order to compare the band and the transmission speed between the communication apparatuses 1.

  The electrical configuration of the communication device 1 will be described. As shown in FIG. 1, the communication device 1 includes a CPU 10 that controls the communication device 1. A ROM 11, a RAM 12, a hard disk drive (hereinafter referred to as “HDD”) 13, an encoder 14, and an input / output interface 19 are connected to the CPU 10 via a bus 18.

  The ROM 11 stores a program for operating the communication device 1, an initial value, and the like. The RAM 12 temporarily stores various information used in the control program. The HDD 13 is a non-volatile storage device that stores various types of information such as a control program. Instead of the HDD 13, a storage device such as an EEPROM or a memory card may be used. Original data of video and audio is input to the encoder 14. The encoder 14 encodes the input original data and outputs it as a set of data of a predetermined size (hereinafter referred to as “data block”). The encoder 14 may be built in the CPU 10 or may be encoded by a control program executed by the CPU 10.

  Connected to the input / output interface 19 are an audio input processing unit 21, an audio output processing unit 22, a video input processing unit 23, a video output processing unit 24, an operation unit 25, an external communication I / F 26, and a drive device 27. . The voice input processing unit 21 processes input from the microphone 31 that inputs voice. The audio output processing unit 22 processes the operation of the speaker 32 that outputs audio. The video input processing unit 23 processes input from the camera 33 that captures video. The video output processing unit 24 processes the operation of the display device 34 that displays video. The operation unit 25 is used for a user to input various instructions to the communication device 1. The operation unit 25 may be connected to the input / output interface 19 from the outside of the communication device 1. The external communication I / F 26 connects the communication device 1 to the network 8. The drive device 27 can read information stored in the storage medium 271. For example, when the communication device 1 is set up, the control program stored in the storage medium 271 is read by the drive device 27 and stored in the HDD 13.

  A band measurement method used in the communication system 100 of the present embodiment will be schematically described. Bandwidth measurement methods used in the communication system 100 are “CaoLe Thanh Man, Go Hasegawa, Masayuki Murata,“ A Study on Inline Network Measurement for Service Overlay Networks ”IEICE Technical Report, The Institute of Electronics, Information and Communication Engineers. , January 17, 2003, Vol. 102, no. 565, p. 53-58 ". Note that the bandwidth measurement method to which the present invention can be applied is not limited to the method described in the above document. The present invention can be applied to any measurement method using a packet transmission interval and a reception interval.

  The measurement principle will be described. In the communication device 1, data is prepared. Header information is added to the prepared data, and a measurement packet is created. When the size of the prepared data is larger than the data size of the packet allowed in the network 8, the prepared data is divided so that a measurement packet can be created. Header information is added to each of the divided data, and a plurality of measurement packets are created. Hereinafter, a set of one or more measurement packets created based on the prepared data is referred to as a “measurement packet group”. The communication device 1 continuously transmits measurement packets constituting the measurement packet group to other communication devices 1 via the network 8. Hereinafter, the communication device 1 that transmits the measurement packet group is referred to as a “transmission device”. The other communication device 1 that receives the measurement packet group is referred to as a “reception device”.

  In the transmission device, after the measurement packet group is transmitted, the next data is prepared and the next measurement packet group is created. The created next measurement packet group is transmitted to the receiving apparatus after the time corresponding to the transmission interval has elapsed since the measurement packet group was transmitted. The process of transmitting the measurement packet group is repeatedly executed while changing the transmission interval.

  If the bandwidth used when transmitting the measurement packet group (hereinafter referred to as “measurement bandwidth”) is less than or equal to the usable bandwidth, the measurement packet group is not congested in the network 8. In this case, the reception interval at which the reception device receives a plurality of measurement packet groups transmitted by the transmission device is ideally the same as the transmission interval. On the other hand, if the measurement band is larger than the usable band, the measurement packet group is congested in the network 8, and the reception interval becomes longer than the transmission interval.

  The transmission device sequentially transmits a plurality of measurement packet groups while moving the measurement band from the wideband side to the narrowband side by gradually increasing the transmission interval. While the measurement band is larger than the usable band, the reception interval is longer than the transmission interval. However, if the transmission interval becomes longer and the measurement band becomes equal to or less than the usable band, the reception interval and the transmission interval become the same. Therefore, the transmission rate at the time when the relationship between the reception interval and the transmission interval changes can be specified as the usable bandwidth.

  The transmission device prepares at least one of video data and audio data as data for creating a measurement packet group. At least one of the video data and audio data is stored and transmitted in a measurement packet that constitutes a measurement packet group, and the usable bandwidth is measured. Accordingly, the communication device 1 can hold a video conference with another communication device 1 while measuring the usable bandwidth of the network 8.

The measurement band used when the measurement packet group is transmitted, the data size of the measurement packet group, and the transmission interval satisfy the relationship of the following equation (1).
Measurement bandwidth (bps) = data size of measurement packet group (bit) / transmission interval (s) (1)
The “data size of the measurement packet group” indicates the size of data prepared for creating the measurement packet group. Since the ratio of the data size of the added header portion is very small compared with the size of the prepared data, it is omitted in the equation (1).

  The relationship between the data size of the measurement packet group and the transmission interval will be described. This will be described with reference to FIGS. As shown by the equation (1), the measurement band is uniquely specified based on the data size and transmission interval of the measurement packet group. When the data size of the measurement packet group is the same regardless of the measurement band, the transmission interval becomes longer as the measurement band moves to the narrow band side. As shown in FIG. 2, it is assumed that the data sizes of the measurement packet groups G1, G2, G3, and G4 are the same. As the measurement band B (B1, B2, B3, and B4) moves from the wideband side B1 to the narrowband side B4, the transmission interval increases in the order of T1, T2, and T3. In FIG. 2, since the data size of the measurement packet groups G1, G2, G3, and G4 is large, each data is divided into two. Two measurement packets created based on the divided data are included in the measurement packet group.

  When the transmission interval of the measurement packet group transmitted from the transmission device is long, the reception device cannot receive the measurement packet for a long time. When the video imaged by the camera 33 (see FIG. 1) of the transmission device is displayed on the display device 34 (see FIG. 1) of the reception device, the measurement packet group including the video data can be received by the reception device for a long time. If it disappears, the image | video currently displayed on the display apparatus 34 will be interrupted. In addition, when the sound acquired by the microphone 31 (see FIG. 1) of the transmitting device is output from the speaker 32 (see FIG. 1) of the receiving device, the measurement packet group including the sound data is received by the receiving device for a long time. If it becomes impossible, the sound output from the speaker 32 will be interrupted. Thus, if the transmission interval of the measurement packet group transmitted from the transmission device becomes long, the video conference is not smoothly performed.

  On the other hand, in the present invention, the fluctuation of the transmission interval is reduced by adjusting the data size of the measurement packet group based on the measurement band. As shown in FIG. 3, the measurement packet groups G1, G2, G3, and G4 are adjusted so that the data size becomes smaller as the corresponding measurement bands B1, B2, B3, and B4 are smaller. Accordingly, the transmission intervals T1, T2, and T3 are approximately the same. Thereby, the period in which the measurement packet group arrives at the receiving apparatus is made uniform. Therefore, the video output from the display device 34 (see FIG. 1) of the receiving device and the sound output from the speaker 32 (see FIG. 1) of the receiving device are not interrupted. As a result, the video conference is performed smoothly.

  A first relationship table 131, which is an example of a first relationship table stored in the HDD 13 of the communication device 1, will be described with reference to FIG. The first relationship table 131 stores a measurement bandwidth (unit: bps), a data size (unit: byte) of a measurement packet group, and a transmission interval (unit: ms) in association with each other. The first relationship table 131 shows data sizes that can be taken when the measurement band is changed in a range of approximately 300 kbps to 2 Mbps. For example, when the measurement bandwidth is 2 Mbps or more, 2000 bytes is selected as the data size of the measurement packet group. When the measurement bandwidth is 1.5 Mbps or more and less than 2 Mbps, 1700 bytes is selected as the data size of the measurement packet group. When the measurement band is not less than 300 kbps and less than 1.5 Mbps, 1400 bytes is selected as the data size of the measurement packet group. When the measurement bandwidth is less than 300 kbps, 500 bytes is selected as the data size of the measurement packet group.

  If the data of the selected size is larger than the data size of the packet allowed in the network 8, it is divided. For example, when Ethernet (registered trademark) is used in the network 8, the prepared data is divided so that the size does not exceed 1500 bytes.

The transmission interval is calculated using equation (1) based on the actual measurement band and the selected data size. For example, when the measurement bandwidth is 500 kbps, 1400 bytes is selected as the data size of the measurement packet group. In this case, the transmission interval is
Transmission interval (ms) = (1400 × 8) (bit) / 500 k (bps) = 22.4
It is calculated as follows. The transmission interval stored in the first relationship table 131 indicates a range of transmission intervals that may be calculated from the corresponding measurement band and data size.

  In the first relationship table 131, the data size is determined based on the output interval allowed when sound is output from the speaker 32. When the sound is output from the speaker 32, it is known that the user usually feels uncomfortable when the sound output interval exceeds 40 ms. Therefore, in the first relationship table 131, the data size is determined so that the transmission interval calculated from the measurement band and the data size is within 40 ms. Even when the measurement band is changed by determining the data size of the measurement packet group based on the first relationship table 131, the transmission interval of the measurement packet group transmitted from the transmission device exceeds 40 ms. Disappear. Since the receiving apparatus can receive the measurement packet group at a cycle not exceeding 40 ms, it can continuously output audio data and provide a smooth video conference to the user.

  With reference to FIG.5 and FIG.6, the main process performed in CPU10 of the transmission apparatus among the communication apparatuses 1 is demonstrated. The main process is started and executed in the CPU 10 when an instruction to execute the usable bandwidth simultaneously with the video conference is input via the operation unit 25. When the main process is activated, it is determined whether an instruction to end the measurement of the usable bandwidth is input via the operation unit 25 (S11). When the instruction to end the measurement of the usable bandwidth is not input (S11: NO), the data size of the measurement packet group is determined (S13, determination process, see FIG. 6).

  The determination process will be described with reference to FIG. First, a range when changing the measurement band is specified. The range of the measurement band is specified based on the usable band measured in the past. The available bandwidth measured in the past is stored in the HDD 13 (S23, see FIG. 5, described later). Next, a plurality of measurement bands are specified within the specified measurement band (S25). The specified plurality of measurement bands are stored in the RAM 12. The first relationship table stored in the HDD 13 is referred to. The data size corresponding to the measurement band specified in S25 is determined as the data size of the measurement packet group (S27). The determined data size is stored in the RAM 12. Based on the equation (1), the transmission interval is calculated and determined for each measurement band from the measurement band specified in S25 and the data size determined in S27 (S29). The determined transmission interval is stored in the RAM 12. FIG. 7 shows a first band table 121 that is an example of the first band table stored in the RAM 12. In the first bandwidth table 121, the measurement bandwidth specified in S25, the data size of the measurement packet group determined in S27, and the transmission interval determined in S29 are associated with each other. The determination process ends, and the process returns to the main process (see FIG. 5).

  After the determination process (S13) is completed, the first band table stored in the RAM 12 is referred to in the main process. One of the measurement bands and the corresponding data size and transmission interval are selected. Data corresponding to the selected data size is prepared. By storing the prepared data in the measurement packet, a measurement packet group is created (S15). The created measurement packet group is transmitted to the receiving device at the selected transmission interval (S17). All the measurement bands stored in the first band table are selected, and it is determined whether the measurement packet group is transmitted to the receiving device (S19). When the measurement band which has not been selected remains (S19: NO), the process returns to S15. The next measurement band stored in the first band table is selected, and the process is repeated.

  When all the measurement bands are selected and the measurement packet group is transmitted (S19: YES), the reception apparatus measures the usable band by receiving the measurement packet group. The measured usable bandwidth is returned from the receiving device to the transmitting device. The returned usable bandwidth is received (S21). The received usable bandwidth is stored in the HDD 13 as a history (S23). The stored history of usable bandwidth is used when the range of the measurement bandwidth is specified in the determination process (S13). The process returns to S11. When an instruction to end the measurement of the usable bandwidth is input via the operation unit 25 (S11: YES), the main process ends.

  As described above, the data size of the measurement packet group is determined based on the measurement band. The transmission interval of the measurement packet group is uniquely determined from the data size and the measurement band. Therefore, by appropriately determining the data size of the measurement packet group according to the measurement band, it is possible to prevent the transmission interval when the measurement packet group is sequentially transmitted from becoming extremely long. The transmission apparatus can avoid a state in which data (video data, audio data, etc.) stored in the measurement packets constituting the measurement packet group does not reach the reception apparatus for a long time. Therefore, the communication device 1 can measure the usable bandwidth while preventing the occurrence of communication delay and maintaining good communication quality.

  In addition, this invention is not limited to the above-mentioned embodiment, A various change is possible. Hereinafter, modifications of the present invention will be described.

<First modification>
In the present invention, in addition to the measurement band, the data size may be specified based on the type of data stored in the measurement packet. Data types include “video”, “audio”, and “video + audio”. “Video” indicates video data (video data) taken by the camera 33 (see FIG. 1). “Audio” indicates audio data (audio data) acquired by the microphone 31 (see FIG. 1). “Video + audio” includes both video data and audio data, and indicates data synchronized with each other.

  The second relationship table 132, which is an example of the second relationship table stored in the HDD 13, will be described with reference to FIG. In the second relationship table 132, the type (“video”, “audio”, “video + audio”), the data size (unit: byte) of the measurement packet group, and the transmission interval (unit: ms) are stored in association with each other. Yes. For example, when the type is “video”, 1500 bytes is selected as the data size of the measurement packet group. When the type is “video + audio”, 1000 bytes is selected as the data size of the measurement packet group. When the type is “voice”, 500 bytes is selected as the data size of the measurement packet group.

  Of the data stored in the measurement packet, the audio data has a higher required real-time property than the video data. This is because if a delay occurs during the communication of audio data, the audio output from the speaker 32 can be heard constantly, which can greatly hinder the smooth execution of the video conference. Therefore, in the second relation table 132, the data size of the corresponding measurement packet group is smaller as the required voice data with higher real-time property is used. This is because when the data size of the measurement packet group is small, the transmission cycle of the corresponding measurement packet group is shortened, and communication delay hardly occurs.

  With reference to FIG. 9, the determination process in a 1st modification is demonstrated. The determination process is called from the main process shown in FIG. The main process is the same as that in the above-described embodiment. When the determination process is called, first, a range in which the measurement band is changed is specified. A plurality of measurement bands are specified within the specified measurement band (S31). The first relationship table stored in the HDD 13 is referred to. The data size corresponding to the measurement band specified in S31 is determined as a data size candidate (data size (1)) of the measurement packet group (S33). Based on equation (1), a transmission interval candidate (transmission interval (1)) is calculated and determined for each measurement band from the measurement band specified in S31 and the data size (1) determined in S33. (S35). Each value is stored in the first bandwidth table 121 (see FIG. 7) of the RAM 12.

  The type of data scheduled to be transmitted to the receiving device is specified (S37). For example, in the transmission device, when shooting by the camera 33 (see FIG. 1) has started, but the microphone 31 (see FIG. 1) has not acquired sound (no sound), only video data is transmitted to the reception device. The Therefore, “video” is specified as the data type. Also, for example, when shooting by the camera 33 (see FIG. 1) has been started and the microphone 31 (see FIG. 1) has acquired audio, data including video data and audio data is sent to the receiving device. Needs to be sent. Therefore, “video + audio” is specified as the data type. The identified type is stored in the RAM 12.

  The second relationship table stored in the HDD 13 is referred to. The data size corresponding to the type specified in S35 is determined as a data size candidate (data size (2)) of the measurement packet group (S39). The determined data size (2) is stored in the RAM 12. Based on the equation (1), a transmission interval candidate (transmission interval (2)) is calculated and determined for each measurement band from the measurement band specified in S31 and the data size (2) determined in S39. (S41). The determined transmission interval (2) is stored in the RAM 12. FIG. 10 shows a second band table 122 that is an example of the second band table stored in the RAM 12. In the second band table 122, the type specified in S37, the data size (2) determined in S39, and the transmission interval (2) determined in S41 are associated with each measurement band.

  The first band table and the second band table stored in the RAM 12 are referred to. From the data size (1) determined in S33, the transmission interval (1) determined in S35, the data size (2) determined in S39, and the transmission interval (2) determined in S41, the measurement packet group The data size and the transmission interval are determined for each measurement band as follows. Of the transmission interval (1) and the transmission interval (2), a transmission interval closer to a predetermined transmission interval (for example, 10 ms) is selected. A data size corresponding to the selected transmission interval is selected. The selected data size is determined as the data size of the measurement packet group (S43). The selected transmission interval is determined as the transmission interval when transmitting the measurement packet group using the corresponding measurement band (S45). By executing the above processing for each measurement band, the data size and transmission interval of the measurement packet group are determined for each measurement band. The determination process ends, and the process returns to the main process (see FIG. 5).

  A specific example will be described. When the measurement band is 2 Mbps, the first band table 121 (see FIG. 7) is referred to, and the data size (1): 2000 bytes and the transmission cycle (1): 8 ms are determined. When the data type is “voice”, the second band table 122 (see FIG. 10) is referred to, and the data size (2): 500 bytes and the transmission cycle (2): 2 ms are determined. In the transmission interval (1) and the transmission interval (2), since the transmission interval (1) is closer to the predetermined transmission interval (10 ms), the data size of the measurement packet group transmitted when the measurement band is 2 Mbps. 2000 bytes are determined, and 8 ms is determined as the transmission cycle.

  When the measurement bandwidth is 800 kbps, the first bandwidth table 121 (see FIG. 7) is referred to, and the data size (1): 1400 bytes and the transmission cycle (1): 14 ms are determined. When the data type is “video + audio”, the second relationship table 132 (see FIG. 8) is referred to, and the data size (2): 1000 bytes and the transmission cycle (2): 10 ms are determined. In the transmission cycle (1) and the transmission cycle (2), since the transmission cycle (2) is closer to a predetermined transmission interval (10 ms), the data size of the measurement packet group transmitted when the measurement band is 800 kbps. 1000 bytes are determined, and 10 ms is determined as the transmission cycle.

  As described above, in the first modification, the data size is determined based on the measurement band and the data type. As a result, when the type of data that requires real-time performance is specified, the data size can be determined so that the transmission interval becomes shorter. As a result, the communication device can measure the usable bandwidth while ensuring the communication quality required for the data stored in the measurement packets constituting the measurement packet group.

  In the first modification described above, the data size and transmission interval of the measurement packet group are determined based on the measurement band and the data type, but the present invention is not limited to this. The data size and transmission interval of the measurement packet group may be determined based only on the data type. For example, the data type may be specified together with the measurement band in S25 of the determination process of FIG. In S27, the second relation table is referred to, and the data size of the measurement packet group may be determined based on the type of data specified in S27. In S29, the transmission interval may be calculated and determined based on the measurement band specified in S25 and the data size determined in S27.

<Second modification>
In the second modification, the communication device 1 creates data (video data, audio data) stored in the measurement packet by the encoder 14. The user can set the data size of the data block created by the encoder 14 for each type of input data. However, the data size of the data block actually output from the encoder 14 varies depending on the characteristics of the original data. For example, when the type of input data is “speech”, even if the data size of the data block is set to 140 bytes, the data size of the actually output data block varies, and the maximum The data size may be 160 bytes. When the type of the input data is “video”, even if the data size of the data block is set to 1300 bytes, the data size of the actually output data block varies, and the maximum data size May be 1500 bytes. In the second modification, the data size of the measurement packet group is determined so that the data block output from the encoder 14 is not divided into a plurality of measurement packet groups. As a result, the data block output from the encoder 14 can be stored and transmitted in the measurement packet without delay.

  The main process in the second modification will be described with reference to FIGS. In S15 in the main process of FIG. 5, a measurement packet group is created by storing the data block output from the encoder 14 in a measurement packet. Other main processing is the same as that in the above embodiment.

  The determination process will be described with reference to FIG. The determination process is called from the main process shown in FIG. When the determination process is called, a plurality of measurement bands are specified (S31). The data size corresponding to the specified measurement band is determined as the data size (1) based on the first relationship table (S33). A transmission interval (1) is calculated and determined for each measurement band from the measurement band specified in S31 and the data size (1) determined in S33 (S35). The measurement bandwidth, data size (1), and transmission interval (1) are stored in the first bandwidth table. The data type is specified (S37), and the data size corresponding to the specified type is determined as the data size (2) (S39). A transmission interval (2) is calculated and determined for each measurement band from the measurement band specified in S31 and the data size (2) determined in S39 (S41). The measurement bandwidth, data size (2), and transmission interval (2) are stored in the second bandwidth table.

  Reference is made to the first bandwidth table and the second bandwidth table. From the data size (1), transmission interval (1), data size (2), and transmission interval (2), the data size and transmission interval of the measurement packet group are determined for each measurement band (S43, S45). The determined data size and transmission interval are stored in the RAM 12 in association with the data type. FIG. 12 shows a third band table 123 which is an example of the third band table stored in the RAM 12. In the third band table 123, the type specified in S37, the data size determined in S43, and the transmission interval determined in S45 are associated with each measurement band.

  The maximum data size of the data block output from the encoder 14 (hereinafter referred to as “maximum block size”) is specified for each data type (S47). The data size stored in the third band table is compared with the maximum block size corresponding to the type of the third band table (S49). When the data size stored in the third band table is equal to or larger than the maximum block size (S49: YES), the determination process ends and the process returns to the main process (see FIG. 5). When the measurement packet group is created based on the data block output from the encoder 14 when the data size stored in the third band table is less than the maximum block size (S49: NO), the data size of the measurement packet group Therefore, the data block must be divided into a plurality of groups and assigned to different measurement packet groups. Therefore, in order to avoid division of the data block, the maximum block size is determined instead as the data size of the measurement packet group (S51). The determined maximum block size is stored in the third band table. Based on the equation (1), the transmission interval is again calculated and determined from the measurement band and the maximum block size (S53). The determined transmission interval is stored in the third band table. The determination process ends, and the process returns to the main process (see FIG. 5).

  As described above, in the second modification, the data size is determined based on the size of the data block output from the encoder 14. Therefore, it is possible to prevent the data block output from the encoder 14 from being assigned to a plurality of measurement packet groups. Since the data block can be packetized without delay, the communication device can quickly transmit the encoded data to the partner device.

  In the second modification described above, the data size and transmission interval of the measurement packet group are determined based on the measurement band and the data size of the data block output from the encoder 14, but the present invention is not limited to this. The data size and transmission interval of the measurement packet group may be determined based only on the block size. For example, the data type may be specified together with the measurement band in S25 of the determination process of FIG. In S27, the second relationship table may be referred to, and the data size (data size (3)) of the measurement packet group may be determined based on the data type specified in S27. The determined data size (3) may be compared with the maximum block size. As a result of the comparison, when the data size (3) is smaller than the maximum block size, the maximum block size may be determined as the data size of the measurement packet group. In S29, the transmission interval may be calculated and determined based on the measurement band specified in S25 and the data size determined in S27.

  In the above-described embodiment, the first modified example, and the second modified example, the transmission interval is determined based on the formula (1). The present invention is not limited to this. The transmission interval may be limitedly stored in advance in the first relationship table and the second relationship table. In S29 in the determination process of FIG. 6 and S33 and S39 in the determination process of FIG. 9, the data size associated with the determined data size may be determined as it is as the transmission interval when transmitting the measurement packet group. Good.

  In the above-described embodiment, the first modification, and the second modification, the data size is determined based on the first relation table and the second relation table, but the present invention is not limited to this. The data size may be determined so that the transmission interval of the measurement packet group is always constant regardless of the measurement band.

  The CPU 10 that performs the processing of S25 of FIG. 6 and S31 of FIG. 9 corresponds to the “first specifying means” of the present invention. The CPU 10 that performs the processes of S27 in FIG. 6 and S33 and S39 in FIG. 9 corresponds to the “first determining means” of the present invention. The CPU 10 that performs the processes of S29 in FIG. 6 and S35 and S43 in FIG. 9 corresponds to the “second determining means” of the present invention. The CPU 10 that performs the process of S15 in FIG. 5 corresponds to the “creating unit” of the present invention, and the CPU 10 that performs the process of S17 corresponds to the “transmitting unit” of the present invention. The CPU 10 that performs the process of S37 in FIG. 9 corresponds to the “second specifying means” of the present invention. The CPU 10 that performs the process of S47 in FIG. 11 corresponds to the “third specifying means” of the present invention. The HDD 13 of FIG. 1 that stores the history of the usable bandwidth corresponds to the “first storage unit” of the present invention. The HDD 13 of FIG. 1 storing the first relationship table and the second relationship table corresponds to the “second storage means” of the present invention.

  The process of S25 of FIG. 6 corresponds to the “first specific step” of the present invention, the process of S27 corresponds to the “first determination step” of the present invention, and the process of S29 is the “second determination step” of the present invention. It corresponds to. The process of S15 in FIG. 5 corresponds to the “creation step” of the present invention, and the process of S17 corresponds to the “transmission step” of the present invention.

1 Communication device 10 CPU
13 HDD
100 Communication System 131 First Relationship Table 132 Second Relationship Table

Claims (5)

A measurement packet group including one or more measurement packets can be transmitted to another device connected to the network while changing the measurement band by sequentially changing the transmission interval, and can be used in the network. A communication device for measuring a usable bandwidth which is a wide bandwidth,
First specifying means for specifying the measurement band;
First determining means for determining a data size of the measurement packet group based on the measurement band specified by the first specifying means;
Second determination means for determining the transmission interval of the measurement packet group based on the data size and the measurement band determined by the first determination means;
Creating means for creating the measurement packet group of the data size determined by the first determining means;
Transmitting means for transmitting the measurement packet group created by the creating means to the counterpart device at the transmission interval determined by the second determining means ;
Second specifying means for specifying a type of data stored in the measurement packet constituting the measurement packet group;
With
The communication apparatus according to claim 1, wherein the first determining unit determines the data size based on the type specified by the second specifying unit . An encoder that outputs data stored in the measurement packet as a data block of a predetermined size;
The creating means includes
The measurement packet group is created by storing the data block of the predetermined size output from the encoder in the measurement packet constituting the measurement packet group,
A third specifying means for specifying the predetermined size;
The first determining means further includes
The communication apparatus according to claim 1, characterized in that to determine the data size to be larger than the predetermined size specified by the third specifying means. Second storage means for storing the measurement band and the data size in association with each other;
The first determining means includes
Referring to the information stored in the second storage means, determining the data size associated with the measurement band specified by the first specifying means as the data size of the measurement packet group. the communication apparatus according to claim 1 or 2, characterized. A measurement packet group including one or more measurement packets can be transmitted to another device connected to the network while changing the measurement band by sequentially changing the transmission interval, and can be used in the network. A communication method executed in a communication device that measures a usable bandwidth which is a wide bandwidth,
A first specifying step of specifying the measurement band;
A first determination step of determining a data size of the measurement packet group based on the measurement band specified by the first specification step;
A second determination step of determining the transmission interval of the measurement packet group based on the data size and the measurement band determined by the first determination step;
A creation step of creating the measurement packet group of the data size determined by the first determination step;
A transmission step of transmitting the measurement packet group created by the creation step to the counterpart device at the transmission interval determined by the second determination step ;
A second specifying step of specifying a type of data stored in the measurement packet constituting the measurement packet group;
With
The communication method according to claim 1, wherein the first determination step determines the data size based on the type specified by the second specification step . A measurement packet group including one or more measurement packets can be transmitted to another device connected to the network while changing the measurement band by sequentially changing the transmission interval, and can be used in the network. A communication program for measuring the usable bandwidth, which is a wide bandwidth,
A first specifying step of specifying the measurement band;
A first determination step of determining a data size of the measurement packet group based on the measurement band specified by the first specification step;
A second determination step of determining the transmission interval of the measurement packet group based on the data size and the measurement band determined by the first determination step;
A creation step of creating the measurement packet group of the data size determined by the first determination step;
A transmission step of transmitting the measurement packet group created by the creation step to the counterpart device at the transmission interval determined by the second determination step ;
Causing the computer to execute a second specifying step of specifying the type of data stored in the measurement packet that constitutes the measurement packet group , and
The first determining step determines the data size based on the type specified by the second specifying step .

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