JP2009152864A - Transmitter, receiver, and data transmission method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce probability that regeneration is not completed in a receiver, to raise use efficiency of a band and to reduce computational complexity in generating or decoding a redundant symbol in a transmitter/receiver. <P>SOLUTION: This transmitter includes means for: coding data to generate a source symbol; generating the redundant symbol from the source symbol; transmitting the source symbol and the redundant symbol, or the redundant symbol; and receiving feedback information from the receiver. The transmitter stops the means for transmitting the source symbol when completion notification for notifying that the regeneration of the source symbol is completed is received by the receiver as the feedback information. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is used for data transmission using redundant packets for erasure correction.

  TCP (Transmission Control Protocol) is mainly used to transmit data to be transmitted on the current Internet completely without loss.

  On the other hand, there is a technique called FEC (Forward Error Correction), which provides a packet loss recovery method different from ARQ (Automatic Repeat reQuest) used for TCP.

  Among the FECs, those that recover lost packets are called erasure correction codes. In this method, a redundant packet for the data other than the original data to be transmitted is generated, and the original packet is regenerated from the redundant packet even if the original data packet is lost.

  Furthermore, the erasure correction code creates only redundant packets and regenerates the original data from the redundant packets, and is called unorganized code, or the Fountain Code that can create almost unlimited redundant packets among unorganized codes. There is what is called (Rateless Erasure Code). Representative examples of the Fountain Code include LT Code and Raptor Code (Non-Patent Document 1).

Amin Shokrollahi, “Raptor codes” IEEE / ACM Transactions on Networking (TON), June 2006

  TCP, which is widely used at present, changes cwnd (Congestion Window) based on ACK (Acknowledgement) from the transmitting device when data transmission is performed, but it is sufficient for high delay or broadband network (Long Fat Pipe) It takes a considerable time for cwnd to increase until a sufficient throughput is achieved.

  Furthermore, since TCP halves cwnd when packet loss is detected, sufficient throughput cannot be realized in a realistic transmission path.

  Further, in the future, when further increase in the bandwidth of the network is demanded, parallel transmission using a plurality of optical paths is promising, but the transmission delay for each path may be different, and the out-of-order (Out-of -Order) packets can occur. If data transmission is performed using TCP in such a case, it is conceivable that the out-of-order packet generation is erroneously detected as a packet loss from the packet loss detection method, and the throughput is reduced by halving cwnd.

  This occurs because ARQ is used for packet loss recovery, and it is difficult to detect packet loss in an environment where out-of-order packets can occur.

  The technique of transmitting complete data to the receiving apparatus using the erasure correction code estimates the packet loss rate to be guaranteed in advance and estimates the amount of redundant packets to be generated. Therefore, when a packet loss exceeding the estimated packet loss rate occurs in the network during transmission, guarantee cannot be performed and the original file cannot be regenerated in the receiving apparatus.

  In addition, if the packet loss rate in the network being transmitted is smaller than the estimated packet loss rate, redundant packets will be sent in excess of the amount necessary to regenerate the original file in the receiving device, As a result, network resources are consumed.

  The present invention has been made to solve such problems, and may occur in a redundant packet setting method using conventional packet loss rate estimation, and there is a possibility that regeneration will not be completed in the receiving apparatus. It is another object of the present invention to provide a transmission apparatus, a reception apparatus, and a data transmission method that can achieve further improvement in bandwidth utilization efficiency and a reduction in the amount of computation when generating or decoding redundant symbols in the transmission / reception apparatus.

  When the present invention is viewed from the viewpoint of a transmission apparatus, the present invention relates to a transmission apparatus that transmits data to a reception apparatus, and generates a source symbol by encoding the data and a redundant symbol from the source symbol. Means for transmitting the source symbol and the redundant symbol or the redundant symbol; and means for receiving feedback information from the receiving device, wherein the regeneration of the source symbol is completed by the receiving device. When the completion notification to be notified is received as the feedback information, the sending means is stopped.

  Further, when the present invention is viewed from the viewpoint of a receiving apparatus, the present invention is a receiving apparatus opposite to the transmitting apparatus of the present invention, and decodes the received source symbol and the redundant symbol or the redundant symbol. Means for regenerating the source symbol, means for generating a completion notification when the regeneration of the source symbol is completed, and means for notifying the completion notification to the transmission apparatus as the feedback information. Features.

  According to this, it is possible to avoid sending redundant symbols from the transmitting device side even after the source symbol regeneration is completed on the receiving device side, eliminating the possibility that the regeneration device will not complete regeneration, It is possible to realize an improvement in utilization efficiency and a reduction in the amount of computation when generating or decoding redundant symbols in the transmission / reception apparatus.

  Alternatively, the transmission apparatus of the present invention encodes the data to generate a source symbol, means for generating a redundant symbol from the source symbol, and means for transmitting the source symbol and the redundant symbol or the redundant symbol And a means for receiving feedback information from the receiving device, and a partial completion notification for notifying that a part or all of the source symbols have been regenerated in the source symbols by the receiving device. Means for weighting the remaining source symbols excluding part or all of the source symbols that have been regenerated by the partial completion notification when received as the feedback information, and selecting the source symbols based on the weights; The source source selected by the means for selecting Means for generating the redundant symbol from Vol, and means for continuing to send the remaining source symbol and the redundant symbol generated by the generating means or the redundant symbol generated by the generating means It is characterized by that.

  Further, the partial completion notification includes a notification when the regeneration of all the source symbols is incomplete, and when the notification is received, means for weighting all the source symbols can be provided.

  In this case, the receiving apparatus according to the present invention is configured to regenerate the source symbol by decoding the received source symbol and the redundant symbol or the redundant symbol, and the source symbol has been completely regenerated. Characterized in that it comprises means for generating a partial completion notification for notifying that part or all of the source symbols have been reproduced, and means for notifying the transmission apparatus of the partial completion notification as the feedback information. .

  The partial completion notification may also include a notification when all the source symbols have not been regenerated.

  Alternatively, the transmission apparatus of the present invention encodes the data to generate a source symbol, means for generating a redundant symbol from the source symbol, and means for transmitting the source symbol and the redundant symbol or the redundant symbol And receiving means for receiving feedback information from the receiving device, and when the incomplete notification for the source symbol that has not been regenerated by the receiving device is received by the receiving device as the feedback information, Means for selecting the source symbol that has not been regenerated by the completion notification; means for generating the redundant symbol from the source symbol selected by the means for selecting; and the source symbol that has not been regenerated and The redundant symbol generated by the generating means Or comprising the means for continuing transmission of said redundant symbols generated by means of this generation.

  The receiving apparatus in this case also includes means for regenerating the source symbol by decoding the received source symbol and the redundant symbol or the redundant symbol, and the source symbol that has not been regenerated. Means for generating an incomplete notification, and means for notifying the incomplete notification to the transmission device as the feedback information.

  According to this, it is possible to avoid sending redundant symbols from the transmitting apparatus side for the source symbols of the part where the regeneration of the source symbol has been completed on the receiving apparatus side, eliminating the possibility that the regeneration will not be completed in the receiving apparatus, Furthermore, it is possible to improve the bandwidth utilization efficiency and reduce the amount of computation when generating or decoding redundant symbols in the transmission / reception apparatus.

  For example, the receiving apparatus of the present invention may include the number of the source symbols that can be regenerated by the regenerating unit, the number of the source symbols that cannot be regenerated, or the ratio of the source symbols that can be regenerated to the total source symbols, or Means for calculating a ratio of the source symbols that have not been regenerated to all source symbols or a combination of any two or more thereof; and means for determining the start or end of feedback information transmission using the indices. Prepare. Thereby, the timing of starting or ending feedback information transmission can be accurately determined.

  Alternatively, the receiving apparatus according to the present invention provides the number of the source symbols that can be regenerated by the regenerating means, the number of the source symbols that cannot be regenerated, or the ratio of the source symbols that can be regenerated to the total source symbols, or Means for calculating a ratio of the ratio of the source symbols not regenerated to all source symbols or a combination of any two or more thereof, and means for changing the content of the feedback information using the index. it can. Thereby, the content of feedback information can be changed appropriately.

  Further, when the present invention is viewed from the viewpoint of a data transmission method, the present invention relates to the data transmission method executed by the transmission device and the reception device when transmitting data from the transmission device to the reception device. An apparatus encoding the data to generate a source symbol; generating a redundant symbol from the source symbol; sending the source symbol and the redundant symbol or redundant symbol; and from the receiving apparatus Receiving the feedback information.

  Further, when the present invention is viewed from the viewpoint of a program, the present invention is a program that, when installed in an information processing apparatus, causes the information processing apparatus to realize a function corresponding to the function of the transmission apparatus or the reception apparatus of the present invention. It is.

  According to the present invention, there is no possibility that the regeneration apparatus does not complete the regeneration, which can occur in the conventional redundant packet setting method using the packet loss rate estimation, and further, the bandwidth utilization efficiency is improved and the redundant symbol is generated in the transmission / reception apparatus. Alternatively, the amount of calculation at the time of decoding is reduced.

(Overview)
In the embodiment of the present invention, when data is transmitted completely without loss, a loss correction code is used instead of ARQ for lost packet loss recovery, and further, the problem of the conventional loss correction code is solved. Try to collaborate.

  The transmitting device transmits a large amount of redundant packets prepared using feedback information, and the receiving device performs regeneration while receiving redundant packets, and sends feedback information according to the regeneration status.

  When the packet loss rate is high, it prevents the regeneration from becoming impossible due to the shortage of redundant packets, and when the packet loss rate is low, the redundant resources are sent unnecessarily to consume network resources. Can be prevented.

  In the following embodiments and drawings, the original file to be transmitted is denoted as “original file”, and the redundant data generated according to the “source symbol” and “Erasure Collection Code” is obtained by dividing the original file into a certain size. Indicated as “redundant symbol”.

(Basic embodiment)
A basic embodiment will be described with reference to FIGS. Note that the basic embodiment is an embodiment common to all embodiments described below.

  FIG. 1 is a diagram illustrating a transmitting apparatus A that transmits an original file and a receiving apparatus B that receives the original file. A state in which the transmission device A and the reception device B are connected via the network N is shown. At this time, the transmitting apparatus A divides the original file to generate source symbols, generates redundant symbols using the Erasure Collection Code, and sends the source symbols and redundant symbols or redundant symbols to the receiving apparatus B as a data stream D. . At this time, the receiving apparatus B sends feedback information F for efficient encoding and decoding to the transmitting apparatus A.

  FIG. 2 is a block configuration diagram of a transmission apparatus A and a reception apparatus B that are common to all the following embodiments. The communication path P in FIG. 2 is, for example, the network N shown in FIG.

  In the following embodiments, transmission apparatus A transmits means for encoding data to generate source symbols, means for generating redundant symbols from source symbols, and means for transmitting source symbols and redundant symbols or redundant symbols. The symbol generation unit A1 includes a feedback reception / analysis unit A2 as means for receiving feedback information from the reception device B.

  In addition, the receiving apparatuses B in all the following embodiments include a symbol reception regeneration unit B1 as means for decoding the received source symbols and redundant symbols or redundant symbols to regenerate the source symbols.

(First embodiment)
A first embodiment will be described with reference to FIGS. In the first embodiment, the transmission symbol generation unit A1 provides means for sending out when the feedback reception / analysis unit A2 receives a completion notification as notification information that the reception apparatus B has completed the regeneration of the source symbol as feedback information. Stop.

  In the first embodiment, the feedback generation unit B2 includes means for generating a completion notification when the regeneration of the source symbol is completed, and means for notifying the transmission apparatus A of the completion notification as feedback information.

  Next, operations of the transmission device A and the reception device B in the first embodiment will be described with reference to the flowchart of FIG. FIG. 3 is a flowchart showing operations of the transmission device A and the reception device B in the first embodiment.

  When the transmission apparatus A starts transmission (step T1), it generates redundant symbols from the source symbols (step T2) until it receives a regeneration completion notification from the reception apparatus B (step T2). Continue sending (step T3).

  On the other hand, when the receiving apparatus B starts receiving (step R1), the receiving apparatus B receives the source symbol and redundant symbol or redundant symbol sent from the transmitting apparatus A (step R2), and performs a regeneration process (step R3). All source symbols are regenerated (step R4) to obtain the original file.

  When all source symbols are regenerated and the original file is obtained (Yes in step R4), a regeneration completion notification is sent to the transmitting apparatus A (step R5), and the reception is terminated (step R6).

  When receiving the regeneration completion notification (Yes in step T4), the transmitting apparatus A ends the generation and transmission of redundant symbols (step T5).

(Second embodiment)
A second embodiment will be described with reference to FIGS. FIG. 4 is a conceptual diagram for explaining the operation of the second embodiment.

  The transmission symbol generation unit A1 of the transmission device A according to the second embodiment provides the feedback of the partial completion notification for notifying that the reception device B has completed the regeneration of part or all of the source symbols in the source symbols. When received as information, the remaining source symbols excluding part or all of the source symbols that have been regenerated by the partial completion notification are weighted, and a means for selecting the source symbols based on this weighting and a means for selecting Means for generating redundant symbols from the selected source symbols, and means for continuing to send the remaining source symbols and redundant symbols generated by the generating means or redundant symbols generated by the generating means.

  Further, the receiving apparatus B in the second embodiment includes means for generating a partial completion notification for notifying that part or all of the source symbols that have been regenerated in the source symbols have been reproduced, Means for notifying the transmission apparatus A of the completion notification as feedback information is provided in the feedback generation unit B2.

  In FIG. 4, the transmission apparatus A divides the original file S, generates source symbols S1 to SN, performs encoding, generates redundant symbols E1 to EM, and sends them. In addition, the receiving device B regenerates the source symbols while receiving the source symbol and the redundant symbol or the data stream D that is a redundant symbol sent from the transmitting device A.

  Since the source symbols S1 'and S3' that have been regenerated in the receiving apparatus B have already been correctly regenerated, the transmitting apparatus A is notified as feedback information Fa that the source symbols have been regenerated. Accordingly, the transmitting apparatus A can know the source symbols S1 'and S3' already regenerated by the receiving apparatus B.

  In the transmitting apparatus A, the source symbols S1 'and S3' received by the receiving apparatus B are stored in the table C, and are used to select source symbols when generating redundant symbols.

  Specifically, in selecting a source symbol to be used when generating a redundant symbol, the receiving apparatus B does not select a source symbol already acquired by the receiving apparatus B, but generates a redundant symbol only from other source symbols. To acquire extra information on the source symbols already acquired by the receiver and to prevent an increase in the amount of extra regeneration calculations, and to generate redundant symbols using weighting etc. for source symbols not received by the receiver B There is a method of facilitating the regeneration in the receiving apparatus B by selecting preferentially sometimes.

  Note that the partial completion notification includes notification when all of the source symbols have not been regenerated, and when the notification is received, all the source symbols are weighted.

(Third embodiment)
A third embodiment will be described with reference to FIGS. FIG. 5 is a conceptual diagram for explaining the operation of the third embodiment.

  The transmission symbol generation unit A1 of the transmission device A in the third embodiment reproduces by the incomplete notification when the reception device B receives the incomplete notification for the source symbol for which the source symbol regeneration has not been completed as feedback information. Means for selecting an uncompleted source symbol, means for generating a redundant symbol from the source symbol selected by the means for selecting, the remaining source symbol and the redundant symbol generated by the means for generating or the generation thereof Means for continuing to send redundant symbols generated by the means for

  In addition, the receiving apparatus B in the third embodiment generates a non-completion notice for a source symbol whose source symbol regeneration has not been completed, and notifies the transmitting apparatus of the non-completion notice as feedback information. Are provided in the feedback generator B2.

  In FIG. 5, as in FIG. 4, the transmitting apparatus A divides the original file S to generate source symbols S <b> 1 to SN, performs encoding, generates redundant symbols E <b> 1 to EM, and sends them. .

  In addition, the receiving device B regenerates the source symbol while receiving the redundant symbol or the source symbol and the redundant symbol sent from the transmitting device A.

  Since the source symbols other than the source symbols S1 ′ and S3 ′ that have not been regenerated in the receiving apparatus B have not yet been regenerated, the fact that the source symbols have not been regenerated is sent to the transmitting apparatus A as feedback information Fb. Notice.

  Accordingly, the transmitting apparatus A can know the source symbols that the receiving apparatus B cannot regenerate. The transmitting apparatus A transmits the source symbol itself notified from the receiving apparatus B as a data stream Db in addition to transmitting the source symbol and the redundant symbol or the redundant symbol.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIGS. FIG. 6 is a conceptual diagram for explaining the operation of the feedback generation unit B2 in the fourth embodiment.

  The feedback generation unit B2 according to the fourth embodiment is configured such that the number of source symbols that can be regenerated by the symbol reception regeneration unit B1 or the number of source symbols that cannot be regenerated or the ratio of source symbols that can be regenerated to all source symbols. Or means for calculating an index I combining the ratio of source symbols that have not been regenerated to all source symbols, or a combination of any two or more thereof; and means for determining the start or end of sending feedback information using the index I. Is provided.

  Alternatively, the feedback generation unit B2 of the fourth embodiment performs the number of source symbols that can be regenerated by the symbol reception regeneration unit B1 or the number of source symbols that cannot be regenerated or all source symbols of the source symbols that can be regenerated. A means for calculating an index I that is a ratio of the source symbols that have not been regenerated or a ratio of all source symbols to a source symbol or a combination of any two or more thereof, and a means for changing the content of feedback information using the index I Prepare.

  In FIG. 6, the receiving apparatus B regenerates the source symbols S1 'and S3' while receiving the source symbols and redundant symbols or redundant symbols E2 'to EM' sent from the transmitting apparatus A. Further, feedback information F is generated by the feedback information generation / transmission unit G and transmitted to the transmission apparatus A.

  At this time, a value serving as an index I for the feedback information to be generated is calculated from the number of source symbols acquired by the receiving apparatus B or the number of source symbols that cannot be regenerated or the ratio to all source symbols to be regenerated. Using the calculated index I, the start and end of transmission of feedback information are determined.

  In addition, the feedback information notified to the transmission apparatus A using the index I is either the regenerated source symbol shown in the second embodiment or the source symbol that has not been regenerated shown in the third embodiment. Or decide whether to use both.

  At the stage when the transmitting apparatus A starts to transmit, since most of the source symbols that cannot be regenerated in the receiving apparatus B, the regenerated source symbol is generated and the transmitting apparatus A is notified as soon as it is generated. Start.

  On the other hand, at the stage where many source symbols are obtained in the receiving apparatus B, it is more efficient to acquire source symbols that have not been regenerated and proceed with regeneration. Notify the symbol. The notification start of the source symbol that has not been regenerated is determined using the calculated “number of source symbols that have been regenerated or source symbols that have not been regenerated or the ratio to the total number of source symbols to be regenerated”. The transmission of this feedback information is completed when the regeneration of all source symbols in receiving apparatus B is completed.

  The operation of the transmitting device A and the receiving device B will be described with reference to FIG. FIG. 7 is a flowchart showing the operations of the transmission apparatus A and the reception apparatus B. The receiving apparatus B starts reception (step N1), receives source symbols and redundant symbols or redundant symbols (step N2), and after the regeneration operation (step N3), the number of source symbols that can be regenerated or The number of source symbols that could not be regenerated, the ratio of the source symbols that could be regenerated to the total source symbols, the ratio of the source symbols that could not be regenerated to the total source symbols, or an index I that combines at least two of them Calculate (step N4). Based on this, feedback information to be transmitted is determined and transmitted (step N5). When the index I reaches a value for ending the transmission of feedback information determined in advance, the transmission of feedback information is terminated (step N6).

  As described above, for feedback information to be transmitted, select notification of regenerated source symbols at the start of transmission, and select notification of source symbols that cannot be regenerated when index I exceeds a certain threshold. The technique to do is mentioned.

  At this time, when transmitting apparatus A starts transmission (step M1), based on feedback information from receiving apparatus B, it generates a redundant symbol from the source symbol (step M2), and the source symbol and redundant symbol or redundant symbol are generated. The sending is continued (step M3). When it is determined that the transmission of the source symbol and the redundant symbol or the redundant symbol is finished based on the feedback information from the receiving apparatus B (Yes in Step M4), the transmission is finished (Step M5).

(Example of the program)
An example of a program that, when installed in the information processing apparatus, causes the information processing apparatus to realize functions corresponding to the functions of the transmission apparatus A and the reception apparatus B of the present embodiment will be described.

  By recording the program of this embodiment on a recording medium, the information processing apparatus can install the program of this embodiment using this recording medium. Alternatively, the program of the present embodiment can be directly installed on the information processing apparatus from the server holding the program of the present embodiment via the network.

  Thereby, using the information processing apparatus, it corresponds to the functions of the transmission symbol generation unit A1, the feedback reception / analysis unit A2 of the transmission device A of the present embodiment, and the symbol reception regeneration unit B1 and the feedback generation unit B2 of the reception device B. Function can be realized.

  The program of this embodiment includes not only a program that can be directly executed by the information processing apparatus but also a program that can be executed by being installed on a hard disk or the like. Also included are those that are compressed or encrypted.

(Explanation of effect)
The first embodiment eliminates the possibility that the regeneration will not be completed in the receiving apparatus B, and has the effect of improving the bandwidth utilization efficiency. In the second to fourth embodiments, the information about the source symbols that the receiving apparatus B has already acquired is notified, the band is not consumed, and the information about the source symbols that are not acquired by the receiving apparatus B is given priority. It is possible to efficiently execute the regeneration operation by notifying.

  For this reason, it has the effect of improving the bandwidth utilization efficiency and reducing the amount of computation when generating or decoding redundant symbols in the transmission / reception apparatus.

  According to the present invention, it can be used to improve transmission quality, improve bandwidth utilization efficiency, and reduce the amount of computation when generating or decoding redundant symbols in a transmission / reception apparatus.

It is a figure which shows the transmitter which transmits an original file, and the receiver which receives it. It is a block block diagram of the transmitter which is common to all embodiment, and a receiver. It is a flowchart which shows operation | movement of the transmitter in 1st embodiment, and a receiver. It is a conceptual diagram for demonstrating operation | movement of 2nd embodiment. It is a conceptual diagram for demonstrating operation | movement of 3rd embodiment. It is a conceptual diagram for demonstrating operation | movement of the feedback production | generation part in 4th embodiment. It is a flowchart which shows operation | movement of the transmitter in 4th embodiment, and a receiver.

Explanation of symbols

A transmitter A1 transmission symbol generator A2 feedback receiver / analyzer B receiver B1 symbol reception regenerator B2 feedback generator C table D data streams E1 to EM, E2 ′ to EM ′ redundant symbols F, Fa, Fb feedback G Feedback information generation and transmission unit I Index N Network P Communication path S Original files S1 to SN, S1 ′, S3 ′ Source symbol

Claims (13)

In a transmitting device that transmits data to a receiving device,
Means for encoding the data to generate source symbols;
Means for generating redundant symbols from the source symbols;
Means for sending the source symbol and the redundant symbol or the redundant symbol;
Means for receiving feedback information from the receiving device,
The transmission device is characterized in that when the reception device receives a completion notification for notifying that the regeneration of the source symbol has been completed as the feedback information, the sending means is stopped. A receiving device facing the transmitting device according to claim 1,
Means for decoding the received source symbol and the redundant symbol or the redundant symbol to regenerate the source symbol;
Means for generating a completion notification upon completion of regeneration of the source symbol;
Means for notifying the transmission device of the completion notification as the feedback information. In a transmitting device that transmits data to a receiving device,
Means for encoding the data to generate source symbols;
Means for generating redundant symbols from the source symbols;
Means for sending the source symbol and the redundant symbol or the redundant symbol;
Means for receiving feedback information from the receiving device,
When the reception device receives a partial completion notification for notifying that part or all of the source symbols have been regenerated in the source symbols as the feedback information, the regeneration is completed by the partial completion notification. Weighting the remaining source symbols excluding a part or all of the source symbols, and selecting the source symbols based on the weights;
Means for generating the redundant symbols from the source symbols selected by the means for selecting;
A transmission apparatus comprising: the remaining source symbols and the redundant symbols generated by the generating means or the means for continuing to transmit the redundant symbols generated by the generating means.   4. The transmission according to claim 3, wherein the partial completion notification includes a notification in a case where regeneration of all of the source symbols is incomplete, and includes means for weighting all the source symbols when the notification is received. apparatus. A receiving device facing the transmitting device according to claim 3 or 4,
Means for decoding the received source symbol and the redundant symbol or the redundant symbol to regenerate the source symbol;
Means for generating a partial completion notification for notifying that reproduction of a part or all of the source symbol that has been regenerated in the source symbol is completed;
Means for notifying the transmission device of the partial completion notification as the feedback information.   The receiving apparatus according to claim 5, wherein the partial completion notification includes a notification in a case where regeneration of all of the source symbols is incomplete. In a transmitting device that transmits data to a receiving device,
Means for encoding the data to generate source symbols;
Means for generating redundant symbols from the source symbols;
Means for sending the source symbol and the redundant symbol or the redundant symbol;
Means for receiving feedback information from the receiving device,
Means for selecting the source symbol that has not been regenerated by the incomplete notification when the incomplete notification for the source symbol that has not been regenerated by the receiving device is received as the feedback information; ,
Means for generating the redundant symbols from the source symbols selected by the means for selecting;
A transmission apparatus comprising: a source symbol that has not been regenerated, and a means for continuing to transmit the redundant symbol generated by the generating means or the redundant symbol generated by the generating means . A receiving device facing the transmitting device according to claim 7,
Means for decoding the received source symbol and the redundant symbol or the redundant symbol to regenerate the source symbol;
Means for generating an incomplete notification for the source symbols that have not been regenerated.
Means for notifying the incomplete notification to the transmitting device as the feedback information. The number of source symbols that could be regenerated by the means for regenerating or the number of source symbols that could not be regenerated or the ratio of the source symbols that could be regenerated to all source symbols or the number of source symbols that could not be regenerated Means for calculating a ratio to all source symbols or a combination of any two or more thereof;
The receiving device according to any one of claims 2, 5, 6, and 8, comprising means for determining start or end of feedback information transmission using the index. The number of source symbols that could be regenerated by the means for regenerating or the number of source symbols that could not be regenerated or the ratio of the source symbols that could be regenerated to all source symbols or the number of source symbols that could not be regenerated Means for calculating a ratio to all source symbols or a combination of any two or more thereof;
The receiving apparatus according to any one of claims 2, 5, 6, and 8, further comprising: means for changing content of feedback information using the index. In the data transmission method executed by the transmission device and the reception device when transmitting data from the transmission device to the reception device,
The transmitting device is
Encoding the data to generate source symbols;
Generating redundant symbols from the source symbols;
Sending the source symbol and the redundant symbol or the redundant symbol;
And receiving the feedback information from the receiving device.   A program that, when installed in an information processing apparatus, causes the information processing apparatus to realize a function corresponding to the function of the transmission apparatus according to any one of claims 1, 3, 4, and 7.   The program which makes the information processing apparatus implement | achieve the function corresponding to the function of the receiver of any one of Claim 2, 5, 6, 8, 9, 10 by installing in an information processing apparatus.

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