JP2009005193A - Communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication terminal which does not transmit any useless frames if frame transmission from a transmission terminal is delayed and is not in time for real-time processing at a receiving terminal. <P>SOLUTION: The communication terminal 1 includes a time counter 14 for keeping time information, a frame formation time adding section 15 for adding time information on the time of formation of a frame before its storage in a transmission buffer for an encapsulated frame, a stay time detector 16 for detecting a stay time based on the time information added to the frame stored in the transmission buffer, and a frame discarding section 17 for discarding a specified frame stored in the transmission buffer. When a transmitter 10 stops transmission of frames temporarily, frame transmission not in time for real-time processing can be avoided by discarding the frames staying for a period longer than a predetermined permissible stay time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a communication terminal that transmits a frame to a receiving terminal via a network, and more particularly to a communication terminal that transmits a frame to the receiving terminal by streaming.

  2. Description of the Related Art Conventionally, there is a method for transmitting image information and audio information in real time from a transmitting terminal to a receiving terminal via a network.

  In a conventional communication terminal, when streaming delivery is performed, when a retransmission of a frame that has not been correctly received is requested, the receiving terminal determines whether it is in time for real-time reproduction (see, for example, Patent Document 1).

Further, the transmission side terminal monitors the data accumulation amount of the transmission buffer, and when the data accumulation amount exceeds a threshold, the transmission data is discarded (for example, see Patent Document 2).
JP 2003-131975 A JP 2006-140984 A

  However, in the communication terminal according to Patent Document 1, retransmission control is performed depending on whether the frame that has arrived at the receiving terminal is correct or incorrect.

  For this reason, there is a problem that frame transmission is delayed because the transmission terminal receives the pause frame due to network congestion, and useless frame transmission cannot be avoided even when it is not in time for real-time processing of the reception terminal. Note that the same problem occurs in the case of backoff due to network congestion instead of the transmission terminal receiving the pause frame.

  Further, since the communication terminal according to Patent Document 2 monitors the accumulated amount of the transmission buffer, it cannot perform control based on the time as to whether it is in time for real-time processing. For this reason, there is a problem that it is impossible to avoid useless transmission of frames.

  Furthermore, the transmission of a frame that is not in time for the real-time processing of the receiving terminal means that the network bandwidth is wasted, and the congestion of the network is further caused after the suspension of transmission from the transmitting terminal is released. There is.

  Further, when a frame that is not in time for real-time processing is discarded at the transmitting terminal, it is discarded regardless of the importance of the frame. For this reason, for example, there is a problem in that it is not possible to control to transmit only MPEG2 I frames or to transmit only audio data in order to ensure the reproduction quality at the receiving terminal at the time of network congestion.

  Also, when a frame that is not in time for real-time processing is discarded at the transmission side terminal, it is discarded regardless of the dependency between the frames. For this reason, for example, when transferring data that needs to be processed in units of VOB (Video Object) such as MPEG2 PS, there is a possibility that the data will be discarded halfway through the VOB. In this case, when the transmission suspension is canceled, the frame is transmitted from the frame in the middle of the VOB, and a frame that cannot be used even if the receiving terminal receives it is transmitted. is there.

  In addition, transmission suspension from the transmission terminal due to a pause frame or back-off is performed regardless of the frame dependency. For this reason, for example, when transferring data that needs to be processed in VOB units, such as MPEG2 PS, if the data is paused when it is transmitted halfway through the VOB, the receiving terminal receives the data received halfway through the VOB. Cannot be processed. For this reason, data received halfway is discarded, and there is a problem that the network bandwidth is wasted and reproduction quality at the receiving terminal is deteriorated.

  In addition, pause of transmission due to a pause frame or back-off has a problem in that the minimum frame required from the receiving terminal cannot be transmitted because reproduction quality at the receiving terminal is not taken into consideration.

  In addition, since the control to the data generation unit is not performed at the time of transmission suspension, it continuously generates data that is discarded without being transmitted by the transmission side terminal, and the power consumption and the bus in the communication terminal are wasted. There is.

  The present invention has been made in view of the above problems, and appropriately avoids useless frame transmission that cannot be performed in real time by the receiving terminal, and wastes network bandwidth between the transmitting terminal and the receiving terminal. It aims at providing the communication terminal which can prevent use appropriately.

  In order to solve the above problems, a communication terminal according to the present invention is a communication terminal that communicates data to a receiving terminal via a network, and generates an encapsulated frame for communicating to the receiving terminal through the network. A data generation unit; a transmission buffer that is generated by the data generation unit and stores frames waiting to be transmitted to the reception terminal; and a frame that is stored in the transmission buffer to the network is transmitted to the reception terminal. A transmission means, a time counter for holding time information, and a frame generation time addition means for adding the time information at which the frame was generated to the frame generated by the data generation means before accumulating in the transmission buffer Based on the time information added to the frame by the frame generation time adding means. A dwell time detecting unit for detecting a dwell time in the transmission buffer, and a frame discard unit for discarding a frame whose dwell time detected by the dwell time detecting unit is equal to or longer than a predetermined dwell time. It is characterized by.

  According to this configuration, when the receiving unit detects network congestion and the transmitting unit temporarily stops frame transmission, the frame discarding unit detects the stay time longer than a predetermined stay allowable time. By discarding the frame, it is possible to avoid sending a frame that is not in time for real-time processing.

  Further, the communication terminal of the present invention further comprises a residence allowable time holding unit that acquires and holds residence allowable time information that allows frame retention in the transmission buffer with the receiving terminal, The frame discarding unit discards a frame that is stored in the transmission buffer and has a residence time detected by the residence time detection unit that is equal to or longer than the residence time allowed by the residence time retention unit. It is characterized by doing.

  According to this configuration, it is possible to more accurately determine whether it is in time for real-time processing, and it is possible to suppress consumption of network bandwidth due to useless frames while maintaining reproduction quality at the receiving terminal.

  In order to solve the above-described problem, the communication terminal of the present invention further includes a frame importance level determination unit that determines the importance level of the frame stored in the transmission buffer, and the frame discard unit includes the dwell time detection unit. Only the frame whose stay time detected in step S is equal to or longer than a predetermined stay allowance time and whose frame importance level is determined to be low by the frame importance level determination unit is discarded.

  According to this configuration, the frame discarding unit can discard only a less important frame among the frames whose detected residence time is equal to or longer than a predetermined residence allowable time. While narrowing down, the frame required by the receiving terminal can be transmitted.

  In order to solve the above problem, the communication terminal of the present invention further comprises frame priority information holding means for acquiring and holding frame priority information with the receiving terminal, and the frame discarding means. Is a frame in which the residence time detected by the residence time detection unit is equal to or longer than a predetermined residence allowable time, and the frame importance level determination unit determines that the importance level is low based on the frame priority information. Only the frame is discarded.

  According to this configuration, it is possible to accurately determine a frame required by the receiving terminal, and it is possible to suppress consumption of the network bandwidth due to a useless frame while maintaining reproduction quality at the receiving terminal.

  In order to solve the above-described problem, the communication terminal of the present invention further includes frame dependency relationship determining means for determining a dependency relationship between a plurality of frames accumulated in the transmission buffer, and the frame discarding means includes the residence time. When discarding a frame whose stay time detected by the detection means is equal to or longer than a predetermined stay allowable time, discarding the frame determined to be dependent on the discard frame by the frame dependence determination means simultaneously Features.

  According to this configuration, the frame discarding unit discards an unnecessary frame by simultaneously discarding a frame subordinate to the discard frame when discarding a frame whose detected residence time is equal to or longer than a predetermined allowable residence time. Can be discarded efficiently.

  In order to solve the above problems, a communication terminal of the present invention is a communication terminal that communicates data to a receiving terminal via a network, and generates an encapsulated frame for communicating to the receiving terminal through the network. Transmitting data generated by the data generating means and storing frames waiting to be transmitted to the receiving terminal, and transmitting the frames stored in the transmitting buffer to the network to the receiving terminal. Transmitting means for receiving the frame via the network, receiving means for detecting congestion of the network by the pause frame, and frame dependency determining means for determining the dependency of the frames accumulated in the transmission buffer. And the transmission means has a dependency relationship in the frame dependency relationship determination means. When a part of the determined frame has already been transmitted, the transmission is not immediately stopped regardless of the congestion state of the network, and the transmission of the dependent frame to the receiving terminal is continued. To do.

  In addition, the communication terminal further includes a frame importance level determination unit that determines the importance level of the frame accumulated in the transmission buffer, and the transmission unit is configured so that a pause time specified in the pause frame elapses. In the case where transmission is resumed before, transmission is performed from a frame determined to be high in importance by the frame importance determination means.

  According to these configurations, the transmission means does not immediately stop transmission regardless of the congestion state when a part of the dependent frame has already been transmitted, and does not transmit until the dependent frame. Since it can be continued, the network bandwidth can be limited while maintaining the reproduction quality of the receiving terminal.

  In addition, the transmission means can maintain the reproduction quality of the receiving terminal because transmission can be performed from a frame with high importance when transmission is resumed before the pause time specified by the pause frame elapses. However, the network bandwidth can be limited.

  In order to solve the above problems, a communication terminal of the present invention is a communication terminal that communicates data to a receiving terminal via a network, and generates an encapsulated frame for communicating to the receiving terminal through the network. Transmitting data generated by the data generating means and storing frames waiting to be transmitted to the receiving terminal, and transmitting the frames stored in the transmitting buffer to the network to the receiving terminal. Transmitting means for receiving the frame via the network, receiving means for detecting congestion of the network by the pause frame, and frame importance level determining means for determining the importance level of the frame accumulated in the transmission buffer. And the transmission means determines that the importance level is high in the frame importance level determination means. The respect to a frame, before the back-off time has elapsed, characterized in that to resume transmission after a predetermined time has elapsed.

  According to this configuration, the transmission unit can resume transmission after a predetermined time regardless of the back-off time for frames with high importance, while maintaining the reproduction quality of the receiving terminal, Network bandwidth can be limited.

  In order to solve the above problems, a communication terminal of the present invention is a communication terminal that communicates data to a receiving terminal via a network, and generates an encapsulated frame for communicating to the receiving terminal through the network. Transmitting data generated by the data generating means and storing frames waiting to be transmitted to the receiving terminal, and transmitting the frames stored in the transmitting buffer to the network to the receiving terminal. Transmitting means for receiving the frame via the network, and receiving means for detecting congestion of the network by the pause frame, wherein the data generating means is a period designated by the pause time designated by the pause frame. Is characterized in that the generation of data is stopped. The data generation means may reduce the speed of data to be generated during the period specified by the pause time specified by the pause frame.

  According to these configurations, since a frame that is not transmitted is not generated unnecessarily, power consumption can be reduced, and it is possible to avoid wasting the bus bandwidth inside the communication terminal. In addition, since frames that are not transmitted are not generated unnecessarily, power consumption can be reduced, and it is possible to avoid wasting bus bandwidth inside the communication terminal.

  Note that the present invention can be realized not only as such a communication terminal but also as a communication method using steps characteristic of the communication terminal, or causing a computer to execute these steps. It can be realized as a program or as an integrated circuit. Needless to say, such a program can be distributed via a recording medium such as a CD-ROM or a transmission medium such as the Internet.

  In the communication terminal according to the present invention, by discarding useless frame transmission, it becomes possible to avoid transmission of a frame that is not in time for real-time processing, and useless use of network bandwidth between the transmission side terminal and the reception terminal Can also be prevented appropriately.

  Embodiments of a communication terminal according to the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of communication terminal 1 according to the first embodiment.

  The communication terminal 1 according to the first embodiment includes a residence time detection unit that detects a residence time in a transmission buffer of a transmission frame, detects network congestion, and temporarily stops frame transmission. By discarding a frame whose detected residence time is equal to or longer than a predetermined residence allowable time, it is possible to avoid sending a frame that is not in time for real-time processing.

  In FIG. 1, a communication terminal 1 and a reception terminal 2 of a transmission side terminal are connected via a network 3, and the communication terminal 1 includes a transmission unit 10, a reception unit 11, a transmission buffer 12, a data generation unit 13, a time A counter 14, a frame generation time adding unit 15, a residence time detecting unit 16, and a frame discarding unit 17 are provided.

  The data generation unit 13 generates a transmission frame and writes it in the transmission buffer.

  The transmission unit 10 transmits the transmission frames stored in the transmission buffer 12 to the network 3. When the receiving unit 11 detects network congestion by a pause frame defined by IEEE 802.3x or a jam signal defined by IEEE 802.3, transmission is stopped according to the regulation.

  The frame generation time adding unit 15 acquires the time when the transmission frame was generated from the time counter 14 and writes it in the transmission buffer 12 as incidental information of the transmission frame.

  The residence time detection unit 16 detects the residence time of the transmission frame by calculating the difference between the time information when the transmission frame written in the transmission buffer 12 is generated and the time counter 14.

  The frame discarding unit 17 discards the transmission frame when the residence time detected by the residence time detection unit 16 is equal to or longer than a predetermined time.

  The operation of the communication terminal 1 according to the first embodiment will be described by taking streaming reproduction from the communication terminal 1 to the receiving terminal 2 as an example.

  FIG. 2 is a flowchart showing an operation procedure of the communication terminal 1 according to the first embodiment.

  First, the data generation unit 13 of the communication terminal 1 generates a transmission frame from the streaming data and writes it in the transmission buffer 12 (S201). At this time, the frame generation time adding unit 15 acquires the time when the transmission frame is generated from the time counter 14 and writes it in the transmission buffer 12 as incidental information of the transmission frame.

  Next, the transmission unit 10 transmits the transmission frame written in the transmission buffer 12 to the network 3 (S202). Note that the receiving terminal 2 receives and reconstructs the streaming data from the transmission frame and reproduces it.

  Next, it is determined whether or not there is a delay in transmission of the transmission frame to the receiving terminal (S203). If there is no delay (No in S203), the bandwidth required for real-time processing of streaming data is determined. Therefore, since the transmission frame transmitted from the communication terminal 1 is received by the time required by the receiving terminal 2, the quality of streaming reproduction can be ensured.

  On the other hand, when the communication terminal 1 receives a pause frame or temporarily detects network congestion (Yes in S203), the transmission unit 10 interrupts transmission and waits for the time specified in the standard before transmission. Resume frame transmission.

  That is, when the transmission unit 10 interrupts transmission (Yes in S203), the residence time detection unit 16 detects the residence time by comparing the generation time information of the transmission frame and the information of the time counter 14 ( S204).

  Then, when the stay time detected by the stay time detection unit 16 is equal to or longer than the time determined from the network bandwidth necessary for streaming playback (Yes in S205), the frame discarding unit 17 The transmission frame is discarded (S206).

  On the other hand, when the residence time is less than the predetermined time (No in S205), the processing from S202 is continued without discarding the transmission frame.

  With the operation described above, the communication terminal 1 according to the first embodiment discards frames that are not in time for real-time processing when transmission is resumed, and does not perform transmission, thereby consuming network bandwidth wastefully. In addition, when transmission is resumed, only frames that are in time for real-time processing are started to be transmitted, so that the recovery time until normal streaming reproduction can be shortened.

  In the description of the first embodiment, the case where the data generation unit 13 writes the transmission frame to the transmission buffer 12 has been described. However, the CPU of the communication terminal 1 may generate the transmission frame and write it to the transmission buffer. The generation of the transmission frame and the writing to the transmission buffer may be performed in separate blocks.

  Further, the frame generation time adding unit 15 writes the time when the transmission frame is generated in the transmission buffer 12 as the additional information of the transmission frame, but the transmission buffer uses the time when the transmission frame is written in the transmission buffer 12 as the additional information of the transmission frame. 12 may be written.

  Further, although the frame generation time adding unit 15 writes the time when the transmission frame is generated as the additional information of the transmission frame in the transmission buffer 12, the additional information of the transmission frame may be written in a buffer different from the transmission buffer 12.

  Furthermore, the frame generation time adding unit 15 writes the time at which the transmission frame was generated in the transmission buffer 12 as the additional information of the transmission frame, but the counter value that can be associated with the real time may be used as the additional information of the transmission frame. Good.

(Embodiment 2)
Hereinafter, a second embodiment of a communication terminal according to the present invention will be described with reference to the drawings.

  FIG. 3 is a block diagram showing a configuration of the communication terminal according to the second embodiment. In FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In addition to the configuration of the first embodiment, the communication terminal 30 according to the second embodiment has an allowable residence time set by receiving a frame transmitted from the receiving terminal 2 by the receiving unit 11 of the communication terminal 30. A residence allowable time information holding unit 31 that holds information is provided.

  Regarding the operation of the communication terminal according to the second embodiment, differences from the operation of the communication terminal according to the first embodiment will be mainly described by taking streaming reproduction from the communication terminal 30 to the receiving terminal 2 as an example.

  FIG. 4 is a flowchart showing an operation procedure of the communication terminal according to the second embodiment.

  First, before starting the streaming reproduction, communication is performed between the communication terminal 1 and the receiving terminal 2 to set the allowable residence time information (S401).

  The following processing is the same as the processing from S201 onward in FIG. 2, and in S402 in the second embodiment, the frame discarding unit 17 determines that the residence time detected by the residence time detection unit 16 is the residence allowance. When the time is longer than the time set in the time information holding unit 31 (Yes in S402), processing for discarding the transmission frame in the transmission buffer 12 is performed (S206).

  On the other hand, when the staying time is less than the predetermined time held in the staying allowable time information holding unit 31 (No in S402), the processing from S202 onward is continued without discarding the transmission frame.

  By the operation described above, in the communication terminal 30 according to the second embodiment, high-accuracy can be obtained by exchanging the allowable residence time information between the communication terminal 30 and the receiving terminal 2 before starting the streaming reproduction. Transmission frame discard control is possible.

  In the second embodiment, the receiving unit 11 sets the allowable staying time information. However, the delay time of the network between the communication terminal 30 and the receiving terminal 2, the receiving buffer capacity of the receiving terminal 2, and the streaming data A result calculated based on at least one of the bit rates may be used as the allowable residence time information.

(Embodiment 3)
Hereinafter, a third embodiment of a communication terminal according to the present invention will be described with reference to the drawings.

  FIG. 5 is a block diagram showing a configuration of communication terminal 50 according to the third embodiment. 5, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 5, the communication terminal 50 according to the third embodiment classifies the transmission frames in the transmission buffer 12, determines the frame of a predetermined type as an important frame, and transmits the frame importance to the frame discarding unit 17. It is characterized by having a determination unit 51.

  Then, the frame discarding unit 17 determines the transmission frame when the residence time detected by the residence time detection unit 16 is equal to or longer than a predetermined time and the frame importance degree determination unit 51 determines that the frame is not important. Discard.

  Regarding the operation of the communication terminal according to the third embodiment, differences from the operation of the communication terminal according to the first embodiment will be described using streaming playback from the communication terminal 50 to the receiving terminal 2 as an example.

  FIG. 6 is a flowchart showing an operation procedure of the communication terminal 50 according to the third embodiment.

  First, before starting the streaming reproduction, the communication terminal 50 sets the minimum necessary transmission frame type in the frame importance degree determination unit 51 to ensure the reproduction quality at the receiving terminal 2 as an important frame type ( S601). Here, the minimum necessary transmission frame type is, for example, audio data or MPEG2 I-frame data.

  When the transmission of the transmission frame is interrupted (Yes in S203), the residence time of the frame is calculated (S204), and the frame importance determination unit 51 determines the type of transmission frame in the transmission buffer 12, and the important frame Is determined (S602), and the frame discarding unit 17 is notified.

  Then, the frame discarding unit 17 has the transmission frame residence time notified from the residence time detection unit 16 for a predetermined time or longer (Yes in S205), and is an important frame notified from the frame importance degree determination unit 51. When it is not determined (No in S602), the transmission frame is discarded (S206).

  On the other hand, when the staying time is less than the predetermined time (No in S205), or even when the staying allowable time is equal to or longer than the predetermined period (Yes in S205), if it is an important frame (Yes in S602). The processing from S202 onward is continued without discarding the transmission frame.

  With the operation described above, the communication terminal 50 according to the third embodiment calculates the residence time of the frame in the transmission buffer 12 and determines the importance of the frame in the frame importance determination unit 51. Since important frames are not discarded, it is possible to transmit only limited streaming data necessary to maintain the minimum reproduction quality even when network congestion occurs.

  That is, in the communication terminal 50 according to the third embodiment, for example, only MPEG2 I frames are transmitted or only audio data is transmitted in order to ensure the reproduction quality at the receiving terminal at the minimum when the network is congested. Control becomes possible.

  In the third embodiment, the frame importance determination unit 51 classifies the type from the transmission frame and determines whether the frame is an important frame. However, the data generation unit 13 sends the transmission frame to the transmission buffer 12. At the time of writing, the type may be written in the transmission buffer 12 as incidental information of the transmission frame, and it may be determined whether the frame is an important frame using the incidental information written.

  In the third embodiment, the frame discarding unit 17 determines that the residence time detected by the residence time detection unit 16 is equal to or longer than a predetermined time and is not important by the frame importance determination unit 51. The case where the transmission frame is discarded in the case where the transmission frame is discarded has been described, but the residence time is equal to or more than a predetermined first residence time judgment value using two residence time judgment values, and the frame importance degree determination unit If the frame is determined to be insignificant by 51, the transmission frame is discarded, and if the residence time is equal to or greater than a predetermined second residence time judgment value, transmission is performed regardless of the judgment result of the frame importance degree determination unit 51. The frame may be discarded.

(Embodiment 4)
Hereinafter, a fourth embodiment of a communication terminal according to the present invention will be described with reference to the drawings.

  FIG. 7 is a block diagram showing a configuration of a communication terminal according to the fourth embodiment. In FIG. 7, the same components as those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 7, the communication terminal 70 includes a frame priority information holding unit 71 that notifies the frame importance level determination unit 51 of the type of transmission frame to be determined as an important frame.

  Regarding the operation of the communication terminal according to the fourth embodiment, differences from the operation of the communication terminal according to the third embodiment will be described with an example of streaming reproduction from the communication terminal 70 to the receiving terminal 2.

  FIG. 8 is a flowchart showing an operation procedure of the communication terminal 70 according to the fourth embodiment.

  In the fourth embodiment, before starting streaming playback, communication between the communication terminal 1 and the receiving terminal 2 performs communication, and the type of transmission frame that is the minimum necessary for ensuring playback quality at the receiving terminal 2 Is used to set the frame priority information in the frame priority information holding unit 71 (S801).

  When transmission of the transmission frame is interrupted (Yes in S203), the residence time is calculated, and the frame importance determination unit 51 determines the type of transmission frame in the transmission buffer 12, and the frame priority information holding unit 71. The frame discarding unit 17 is notified of whether the frame is an important frame according to the information held in the frame.

  Then, the frame discarding unit 17 determines that the residence time of the transmission frame notified from the residence time detection unit 16 is equal to or longer than a predetermined time (Yes in S205) and adds the frame priority information notified from the frame importance degree determination unit 51 to the frame priority information. If it is not determined that it is an important frame based on this (No in S802), the transmission frame is discarded (S206).

  On the other hand, if the staying time is less than the predetermined time (No in S205), or even if the staying allowable time is equal to or longer than the predetermined period (Yes in S205), it is an important frame based on the frame priority information. If it is determined (Yes in S802), the processing from S202 onward is continued without discarding the transmission frame.

  By the operation described above, in the communication terminal 70 according to the fourth embodiment, the frame priority information is exchanged between the communication terminal 70 and the receiving terminal 2 before the streaming playback is started, so that the receiving terminal 2 Can be easily maintained.

(Embodiment 5)
Hereinafter, a fifth embodiment of a communication terminal according to the present invention will be described with reference to the drawings.

  FIG. 9 is a block diagram showing a configuration of a communication terminal according to the fifth embodiment. In FIG. 9, the same components as those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 9, in addition to the configuration of the third embodiment, the communication terminal 90 determines a dependency relationship between a plurality of transmission frames written in the transmission buffer 12 and notifies the frame discarding unit 17 of a frame dependency relationship determination. Part 91 is provided.

  The frame discarding unit 17 determines whether or not the residence time detected by the residence time detection unit 16 is equal to or longer than a predetermined time and is determined to be an unimportant frame by the frame importance degree determination unit 51. A plurality of transmission frames determined to have a dependency by the relationship determining unit 91 are discarded.

  Regarding the operation of the communication terminal according to the fifth embodiment, differences from the operation of the communication terminal according to the first embodiment will be described by taking streaming reproduction from the communication terminal 90 to the receiving terminal 2 as an example.

  FIG. 10 is a flowchart showing an operation procedure of the communication terminal according to the fifth embodiment.

  Here, a series of data processed at the time of streaming reproduction, for example, each frame such as MPEG2 I frame, P frame, and B frame, and data for 1 GOP do not fit in one transmission frame, so it is divided into a plurality of transmission frames. Is done. The receiving terminal can start data processing for streaming reproduction after receiving all of a plurality of transmission frames generated by dividing a series of data. That is, when a part of a plurality of transmission frames generated by dividing a series of data cannot be received, the series of data cannot be processed normally.

  In the communication terminal according to the fifth embodiment, when transmission is interrupted, the frame importance determination unit 51 determines the type of transmission frame in the transmission buffer 12, and determines whether or not the frame is an important frame. Notify

  The frame dependency determining unit 91 also determines the dependency between a plurality of transmission frames written in the transmission buffer 12, for example, which transmission frame is generated by dividing one MPEG2 P frame. Are notified to the frame discarding unit 17.

  Then, the frame discarding unit 17 determines whether the residence time of the transmission frame notified from the residence time detection unit 16 is equal to or longer than a predetermined time (Yes in S205) and is an important frame notified from the frame importance degree determination unit 51. It is determined that the frame is not an important frame (No in S1001), and it is determined that there is a dependency with the transmission frame determined to be not important based on the transmission frame dependency information notified from the frame dependency relationship determination unit 91. If so (Yes in S1002), a process of discarding all transmission frames stored in the transmission buffer 12 is performed (S206).

  On the other hand, if the staying time is less than the predetermined time (No in S205), or even if the staying allowable time is longer than the predetermined period (Yes in S205), it is important based on the determination result of the frame dependency determination unit. If it is determined that there is a dependency relationship with the non-frame (No in S1002), the processing from S202 is continued without discarding the transmission frame.

  With the operation described above, in the communication terminal according to the fifth embodiment, data processing is performed even if the reception terminal 2 receives the data by discarding a transmission frame generated by dividing a series of data collectively. It is possible to avoid transmitting a transmission frame that cannot be performed.

  That is, in the communication terminal according to the fifth embodiment, for example, when data that needs to be processed in units of VOB (Video Object) such as MPEG2 PS is transferred, there is a possibility that the VOB may be discarded halfway. In this case, when the transmission suspension is canceled, it is transmitted from the frame in the middle of the VOB, and a frame that cannot be used even if the receiving terminal receives it is transmitted. Disappear.

  In the fifth embodiment, the stay time of the transmission frame notified from the stay time detection unit 16, the determination result as to whether the frame is the important frame notified from the frame importance degree determination unit 51, and the frame dependency relationship determination The frame discarding unit 17 discards a plurality of transmission frames based on the transmission frame dependency information notified from the unit 91, but the transmission frame residence time notified from the residence time detection unit 16 and the frame The frame discarding unit 172 may be configured to discard a plurality of transmission frames based on the transmission frame dependency relationship information notified from the dependency relationship determining unit 91.

(Embodiment 6)
The sixth embodiment of the communication terminal according to the present invention will be described below with reference to the drawings.

  FIG. 11 is a block diagram showing a configuration of communication terminal 110 according to the sixth embodiment.

  In FIG. 11, the communication terminal 110 on the transmission side is connected to the reception terminal 2 via the network 3, and includes a transmission unit 10, a reception unit 11, a transmission buffer 12, a data generation unit 13, and a frame dependency relationship determination unit 91. It has.

  The data generation unit 13 generates a transmission frame and writes it in the transmission buffer.

  The transmission unit 10 transmits the transmission frame in the transmission buffer 12 to the network 3. When the receiving unit 11 detects network congestion by a pause frame defined by IEEE 802.3x or a jam signal defined by IEEE 802.3, transmission is stopped according to the regulation.

  The frame dependency relationship determination unit 111 determines the dependency relationship between a plurality of transmission frames written in the transmission buffer 12, and determines whether the currently transmitted transmission frame or the previously transmitted transmission frame and the next transmission frame are transmitted. The transmission unit 10 is notified of the dependency relationship.

  The operation of the communication terminal according to the sixth embodiment will be described by taking streaming reproduction from the communication terminal 110 to the receiving terminal 2 as an example.

  FIG. 12 is a flowchart showing an operation procedure of the communication terminal according to the sixth embodiment.

  First, in the communication terminal 110, the data generation unit 13 generates a transmission frame from the streaming data and writes it in the transmission buffer 12 (S201). The transmission unit 10 starts transmission of the transmission frame written in the transmission buffer 12 to the network 3 (S202).

  When a bandwidth required for real-time processing of streaming data is secured (No in S203), there is no delay in transmission of the transmission frame, and the reception terminal 2 receives the transmission frame transmitted from the communication terminal 1. Since it is received before the requested time, the quality of streaming playback can be ensured.

  On the other hand, if the communication terminal 1 receives a pause frame or temporarily detects network congestion and a transmission delay occurs (Yes in S203), the transmission unit 10 normally interrupts transmission. The transmission of the transmission frame is resumed after waiting for the time specified in the standard.

  However, a series of data processed at the time of streaming playback, for example, each frame such as MPEG2 I frame, P frame, B frame, and data for 1 GOP cannot be contained in one transmission frame, and thus are divided into a plurality of transmission frames. The The receiving terminal can start data processing for streaming reproduction after receiving all of a plurality of transmission frames generated by dividing a series of data.

  That is, when a part of a plurality of transmission frames generated by dividing a series of data cannot be received, the series of data cannot be processed normally. Therefore, if the transmission unit 10 stops transmission before transmission of a plurality of transmission frames generated by dividing a series of data, data processing is stopped at the reception terminal 2.

  Therefore, when communication terminal 110 according to the sixth embodiment receives a pause frame or temporarily detects network congestion (Yes in S203), transmission unit 10 notifies frame dependency relationship determination unit 111. Based on the dependency information between the transmitted frames, the transmission is interrupted after all transmission frames that are currently being transmitted or have a dependency relationship with the previously transmitted transmission frame have been transmitted (S1201), and wait for the time specified in the standard. From (Yes in S1202), transmission of the transmission frame is resumed (S1203).

  With the operation described above, in the communication terminal 110 according to the sixth embodiment, it is possible to ensure reproduction quality without hindering data processing at the receiving terminal 2.

(Embodiment 7)
The seventh embodiment of the communication terminal according to the present invention will be described below with reference to the drawings.

  FIG. 13 is a block diagram showing the configuration of the communication terminal according to the seventh embodiment. In place of the frame dependence relationship determining unit in FIG. 11, the transmission frames in the transmission buffer 12 are classified and predetermined types are shown. The frame importance level determination unit 131 determines that the frame is an important frame and notifies the transmission unit 10 of the frame.

  Hereinafter, the operation of communication terminal 130 according to the seventh embodiment will be described by taking streaming reproduction from communication terminal 130 to receiving terminal 2 as an example.

  FIG. 14 is a flowchart showing an operation procedure of the communication terminal according to the seventh embodiment.

  First, before starting the streaming reproduction, the communication terminal 130 sets the minimum necessary transmission frame type to ensure the reproduction quality at the receiving terminal 2 as the important frame type in the frame importance degree determination unit 131 ( S1401). Here, the minimum required transmission frame type is audio data, MPEG2 I-frame data, or the like.

  In the communication terminal 1, the data generation unit 13 generates a transmission frame from the streaming data and writes it in the transmission buffer 12 (S201). The transmission unit 10 transmits the transmission frame written in the transmission buffer 12 to the network 3 (S202).

  When the bandwidth required for real-time processing of streaming data is secured (No in S203), the transmission frame transmitted from the communication terminal 1 is received by the time required by the reception terminal 2, so that the quality of streaming reproduction is Can be secured.

  On the other hand, when the communication terminal 1 receives a pause frame or temporarily detects network congestion (Yes in S203), the transmission unit 10 interrupts transmission (S1402) and waits for the time specified in the standard. After that, it is necessary to resume transmission of the transmission frame.

  That is, when transmission is interrupted (S1402), the frame importance level determination unit 131 determines the type of transmission frame in the transmission buffer 12, and notifies the transmission unit 10 whether it is an important frame.

  Next, according to the notification from the frame importance determination unit 131, the transmission unit 10 is determined to be important for ensuring reproduction quality at the reception terminal 2 before the specified transmission suspension period elapses. A transmission frame is transmitted (S1404).

  Through the operations described above, the communication terminal according to the seventh embodiment can transmit only the streaming data necessary for maintaining the minimum reproduction quality even when network congestion occurs. .

(Embodiment 8)
Hereinafter, an eighth embodiment of a communication terminal according to the present invention will be described with reference to the drawings.

  FIG. 15 is a block diagram showing a configuration of communication terminal 150 according to the eighth embodiment, and includes transmission unit 10, reception unit 11, transmission buffer 12, and data generation unit 13.

  The data generation unit 13 generates a transmission frame and writes it in the transmission buffer. When the receiving unit 11 detects network congestion by a pause frame defined by IEEE 802.3x or a jam signal defined by IEEE 802.3, data generation and writing to the transmission buffer 12 are stopped.

  The transmission unit 10 transmits the transmission frame of the transmission buffer 12 to the network 3. When the receiving unit 11 detects network congestion by a pause frame defined by IEEE 802.3x or a jam signal defined by IEEE 802.3, transmission is stopped according to the regulation.

  Next, the operation of communication terminal 150 according to the eighth embodiment will be described by taking streaming reproduction from communication terminal 150 to receiving terminal 2 as an example.

  FIG. 16 is a flowchart showing an operation procedure of the communication terminal according to the eighth embodiment.

  In the communication terminal 150, the data generation unit 13 generates a transmission frame from the streaming data and writes it in the transmission buffer 12 (S201). The transmission unit 10 transmits the transmission frame written in the transmission buffer 12 to the network 3 (S202).

  When the bandwidth required for real-time processing of streaming data is secured (No in S203), the transmission frame transmitted from the communication terminal 150 is received by the time required by the receiving terminal 2, so that the quality of streaming playback is ensured. it can.

  On the other hand, when the communication terminal 150 receives a pause frame or temporarily detects network congestion (Yes in S203), the transmission unit 10 interrupts transmission and the data generation unit 13 generates a transmission frame. Writing to the transmission buffer 12 is stopped (S1601).

  After the transmission is interrupted, after waiting for the time defined in the standard (Yes in S1202), the transmission unit 10 resumes transmission of the transmission frame (S1203), and the data generation unit 13 generates the transmission frame and the transmission buffer. 12 is resumed (S1602).

  Through the operation described above, the communication terminal 150 according to the eighth embodiment can suppress wasteful power consumption by stopping the generation of transmission frames in a state where network congestion occurs and transmission is not possible. In addition, it is possible to suppress wasteful consumption of the bandwidth of the internal bus of the communication terminal 150.

  In the eighth embodiment, the case where the transmission interruption of the transmission unit 10 and the stop of the data generation unit 13 are controlled simultaneously has been described. However, a time difference is provided between the transmission interruption of the transmission unit 10 and the stop of the data generation unit 13. May be.

  In addition, the transmission frame already written in the transmission buffer 12 when transmission is interrupted is configured to be transmitted when transmission is resumed. The frame discarding unit in the communication terminal according to the first to fifth embodiments of the present invention is combined. Also good.

  As described above, the communication terminal of the present invention can avoid transmission of a frame that is not in time for real-time processing. In addition, it is possible to more accurately determine whether it is in time for real-time processing, and it is possible to suppress consumption of network bandwidth due to useless frames while maintaining reproduction quality at the receiving terminal. It is useful as an apparatus for transmitting a frame required by a receiving terminal while narrowing down a network band to be used. Further, it is useful as an apparatus for limiting the network bandwidth while maintaining the reproduction quality of the receiving terminal. Further, it is possible to reduce power consumption, and is useful as a device that avoids wasteful consumption of the bus bandwidth inside the communication terminal.

  The communication terminal according to the present invention can be applied to, for example, a PC, a PDA, a portable terminal, etc. that perform frame transmission to a receiving terminal for real-time processing.

Block diagram of communication terminal according to Embodiment 1 The flowchart figure which shows the operation | movement procedure of the communication terminal which concerns on Embodiment 1. Block diagram of communication terminal according to Embodiment 2 The flowchart figure which shows the operation | movement procedure of the communication terminal which concerns on Embodiment 2. Block diagram of communication terminal according to Embodiment 3 The flowchart figure which shows the operation | movement procedure of the communication terminal which concerns on Embodiment 3. Block diagram of communication terminal according to embodiment 4 The flowchart figure which shows the operation | movement procedure of the communication terminal which concerns on Embodiment 4. Block diagram of communication terminal according to embodiment 5 The flowchart figure which shows the operation | movement procedure of the communication terminal which concerns on Embodiment 5. Block diagram of communication terminal according to Embodiment 6 The flowchart figure which shows the operation | movement procedure of the communication terminal which concerns on Embodiment 6. FIG. Block diagram of communication terminal according to Embodiment 7 The flowchart figure which shows the operation | movement procedure of the communication terminal which concerns on Embodiment 7. FIG. Block diagram of communication terminal according to embodiment 8 The flowchart figure which shows the operation | movement procedure of the communication terminal which concerns on Embodiment 8.

Explanation of symbols

1, 30, 50, 70, 90, 110, 130, 150 Communication terminal 2 Reception terminal 3 Network 10 Transmission unit 11 Reception unit 12 Transmission buffer 13 Data generation unit 14 Time counter 15 Frame generation time addition unit 16 Residence time detection unit 17 Frame discard unit 31 Retention allowable time information holding unit 51,131 Frame importance level determining unit 71 Frame priority level information holding unit 91,111 Frame dependency relationship determining unit

Claims (15)

A communication terminal for communicating data to a receiving terminal via a network,
Data generating means for generating an encapsulated frame for communicating to the receiving terminal through a network;
A transmission buffer that is generated by the data generation means and accumulates frames waiting to be transmitted to the receiving terminal;
Transmitting means for transmitting frames stored in the transmission buffer to the network to the receiving terminal;
A time counter that holds time information;
Frame generation time adding means for adding time information at which the frame was generated before accumulating in the transmission buffer with respect to the frame generated by the data generating means;
Based on the time information added to the frame in the frame generation time addition means, a residence time detection means for detecting a residence time of the frame in the transmission buffer;
A communication terminal comprising: a frame discarding unit that discards a frame in which the residence time detected by the residence time detection unit is equal to or longer than a predetermined residence allowable time. The communication terminal further includes:
In addition to receiving frames from the network, the receiver includes a receiving means for detecting network congestion,
The frame discarding means detects the congestion of the network when the receiving means detects a congestion of the frame and the staying time detected by the staying time detecting means when the sending means temporarily stops sending frames. The communication terminal according to claim 1, wherein the frame is discarded. The communication terminal further includes:
A retention allowable time holding means for acquiring and holding retention allowable time information that allows frame retention in the transmission buffer with the receiving terminal,
The frame discarding unit includes a frame stored in the transmission buffer, the frame having the residence time detected by the residence time detection unit being equal to or longer than the residence allowable time held by the residence allowable time holding unit. The communication terminal according to claim 1, wherein the communication terminal is discarded. The communication terminal further includes:
Frame importance determination means for determining the importance of frames accumulated in the transmission buffer,
The frame discarding unit discards only frames whose residence time detected by the residence time detection unit is equal to or longer than a predetermined allowable residence time and whose frame importance is determined to be low by the frame importance determination unit. The communication terminal according to claim 1, wherein: The frame discarding means, when the stay time of the frame in the transmission buffer detected by the stay time detection means is equal to or longer than a second stay permission time longer than the stay permission time, The communication terminal according to claim 4, wherein the frame is discarded regardless of the determination result. The communication terminal further includes:
Frame priority information holding means for acquiring and holding frame priority information with the receiving terminal,
The frame discarding unit is a frame whose residence time detected by the residence time detection unit is equal to or longer than a predetermined residence allowable time, and the frame importance level determination unit has a low importance level based on the frame priority information. Only the frame determined to be discarded is discarded. The communication terminal according to claim 4, wherein: The communication terminal further includes:
Frame dependency determining means for determining a dependency relationship between a plurality of frames accumulated in the transmission buffer,
The frame discarding unit determines that the frame dependency relationship determining unit has a dependency relationship with the discarded frame when discarding a frame whose stay time detected by the stay time detecting unit is equal to or longer than a predetermined allowable residence time. The communication terminal according to claim 4, wherein the frames to be discarded are discarded simultaneously. A communication terminal for communicating data to a receiving terminal via a network,
Data generating means for generating an encapsulated frame for communicating to the receiving terminal through a network;
A transmission buffer that is generated by the data generation means and accumulates frames waiting to be transmitted to the receiving terminal;
Transmitting means for transmitting frames stored in the transmission buffer to the network to the receiving terminal;
Receiving means for receiving a frame via the network and detecting network congestion by a pause frame;
Frame dependency relationship determining means for determining the dependency relationship of the frames accumulated in the transmission buffer,
The transmission means does not immediately stop transmission regardless of the congestion state of the network when a part of the frame determined to have the dependency by the frame dependency relation determination means has already been transmitted. A communication terminal characterized by continuing transmission of a frame to the receiving terminal. The communication terminal according to claim 8, wherein the transmission means resumes transmission before a pause time specified in the pause frame elapses. The communication terminal further includes:
Frame importance determination means for determining the importance of frames accumulated in the transmission buffer,
The transmission means transmits from a frame determined to be high in importance by the frame importance determination means when transmission is resumed before the pause time specified in the pause frame elapses. The communication terminal according to claim 8. A communication terminal for communicating data to a receiving terminal via a network,
Data generating means for generating an encapsulated frame for communicating to the receiving terminal through a network;
A transmission buffer that is generated by the data generation means and accumulates frames waiting to be transmitted to the receiving terminal;
Transmitting means for transmitting frames stored in the transmission buffer to the network to the receiving terminal;
Receiving means for receiving a frame via the network and detecting network congestion by a pause frame;
Frame importance level judging means for judging the importance level of the frames accumulated in the transmission buffer,
The transmission means resumes transmission after a predetermined time elapses before a back-off time elapses for a frame determined to be high in importance by the frame importance level determination means. Terminal. A communication terminal for communicating data to a receiving terminal via a network,
Data generating means for generating an encapsulated frame for communicating to the receiving terminal through a network;
A transmission buffer that is generated by the data generation means and accumulates frames waiting to be transmitted to the receiving terminal;
Transmitting means for transmitting frames stored in the transmission buffer to the network to the receiving terminal;
And receiving means for receiving a frame via the network, and detecting network congestion by a pause frame,
The communication terminal characterized in that the data generation means stops generating data during a period specified by a pause time specified by the pause frame. The communication terminal according to claim 12, wherein the data generation means reduces the speed of data to be generated during a period specified by a pause time specified by the pause frame. A communication method used for a communication terminal for communicating data to a receiving terminal via a network,
The communication terminal is at least
A transmission buffer for accumulating frames waiting to be transmitted to the receiving terminal;
A time counter that holds time information,
The communication method is:
A data generation step of generating an encapsulated frame for communicating to the receiving terminal through a network;
Transmitting a frame stored in the transmission buffer to the network to the receiving terminal;
A frame generation time addition step of adding time information at which the frame was generated before accumulating in the transmission buffer to the frame generated in the data generation step;
A residence time detecting step of detecting a residence time of the frame in the transmission buffer based on the time information added to the frame in the frame generation time addition step;
And a frame discarding step of discarding a frame in which the residence time detected in the residence time detection step is equal to or longer than a predetermined residence allowable time. A program used for a communication terminal for communicating data to a receiving terminal via a network,
The communication terminal is at least
A transmission buffer for accumulating frames waiting to be transmitted to the receiving terminal;
A time counter that holds time information,
The program is
A data generation step of generating an encapsulated frame for communicating to the receiving terminal through a network;
Transmitting a frame stored in the transmission buffer to the network to the receiving terminal;
A frame generation time addition step of adding time information at which the frame was generated before accumulating in the transmission buffer to the frame generated in the data generation step;
A residence time detecting step of detecting a residence time of the frame in the transmission buffer based on the time information added to the frame in the frame generation time addition step;
A program that causes a computer to execute a frame discarding step of discarding a frame in which the residence time detected in the residence time detection step is equal to or longer than a predetermined residence allowable time.

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