WO2003105420A1 - Procede de communication de donnees et appareil de transmission de donnees - Google Patents

Procede de communication de donnees et appareil de transmission de donnees Download PDF

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Publication number
WO2003105420A1
WO2003105420A1 PCT/JP2003/006899 JP0306899W WO03105420A1 WO 2003105420 A1 WO2003105420 A1 WO 2003105420A1 JP 0306899 W JP0306899 W JP 0306899W WO 03105420 A1 WO03105420 A1 WO 03105420A1
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WIPO (PCT)
Prior art keywords
data
buffer
unit
transmission
stored
Prior art date
Application number
PCT/JP2003/006899
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English (en)
Japanese (ja)
Inventor
藤井　秀和
西村　崇
Original Assignee
シャープ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by シャープ株式会社 filed Critical シャープ株式会社
Priority to JP2004512359A priority Critical patent/JP4033860B2/ja
Priority to AU2003244101A priority patent/AU2003244101A1/en
Publication of WO2003105420A1 publication Critical patent/WO2003105420A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L49/00—Packet switching elements
    • H04L49/90—Buffering arrangements

Definitions

  • the present invention relates to a data communication method and a data transmission device in a communication system using a transmission path in which an error such as wireless communication or power line communication occurs, and in particular, to a data communication method and a data transmission method in a communication system that performs data transfer in real time.
  • Data transmission device Background art
  • an error correction code is added for each packet unit or for each of a plurality of block units obtained by dividing one bucket into a plurality.
  • the receiving side makes a retransmission request based on the request.
  • a retransmission request is made by the receiving side in this way, data erroneously received by the receiving side is retransmitted by the transmitting side in accordance with the retransmission request from the receiving side.
  • a setting is made such that data transmission is performed from a specific transmission device to a reception device in a predetermined period, and a communication band for each communication device is secured.
  • FIG. 11 is a block diagram showing a data transmission device used in a conventional wireless communication system. 2 shows the internal configuration of the unit 201.
  • the sequence number is added by the sequence number adding section 13, and then the time stamp adding section 14 is used to receive the packet.
  • the information about the playback time to be played back by the is added and temporarily stored in the transmission buffer 16.
  • the retransmission request analysis unit 18 analyzes the reception status of the reception side from the ACK signal from the reception side received by the reception unit 17 via the antenna 21 and transmits information on the packet to be retransmitted to the transmission data.
  • Inform management unit 15 When the transmission period set for the data transmission device 201 starts, the transmission data management unit 15 transmits the data to be transmitted from the retransmission packet held in the transmission buffer 16 and the new packet. Search for the packet.
  • the packet is transmitted from the transmission buffer 16 in the order of the stored sequence number by a predetermined packet amount until the transmission period ends. read out.
  • the packet read from the transmission buffer 16 has the error correction code added by the error correction code addition unit 20 for each bucket or each of a plurality of blocks, and is transmitted from the transmission unit 19 via the antenna 21. Is performed.
  • the discard control operation according to the flowchart of FIG. 12 is started.
  • the reproduction time of the packet stored in the transmission buffer 16 and having the earliest reproduction time on the receiving side is determined.
  • Confirm S101
  • the processing operation of S101 is performed again.
  • the data transmission device performs a transmission operation in a preset transmission period according to the flowchart of FIG. Check the start time of the transmission period using a timer (not shown) in the transmission data management unit 15, or receive a signal indicating transmission permission from the outside at the reception unit 17 and allow the retransmission request analysis unit 18 to permit transmission.
  • the transmission data management unit 15 confirms the start time of the transmission period by recognizing the transmission period, the transmission period is started and the transmission operation is started (S111).
  • the ACK signal from the receiving side received by the receiving unit 17 is analyzed by the retransmission request analysis unit 18, and the retransmission bucket confirmed and the new bucket to be newly transmitted are transmitted to the transmission data management unit. 15 is searched (S1 1 2). Based on the search result, the retransmission bucket to be transmitted and the sequence number of the new bucket stored in the transmission buffer 16 are stored in the transmission data management unit 15 (S113). Based on the sequence number stored in the transmission data management unit 15, the transmission data management unit 15 determines whether the retransmission packet to be transmitted and the new packet exist in the transmission buffer 16 or not. (S114).
  • the transmission data management unit 15 confirms the current time, and the remaining transmission period is sufficient to transmit the bucket to be transmitted. It is determined whether or not (S1 15). At this time, if it is determined that transmission is not possible (No), all processing is terminated, while if it is determined that transmission is sufficient (Yes), the packet to be transmitted is transmitted. Later (S116), the process proceeds to S114. Then, the processing of 3114 to 3116 is repeated until there is no more packet to be transmitted or the transmission period is not enough time for transmission.
  • the error recovery capability by retransmission reaches its limit, and there is a problem that data to be continuously processed such as video and audio is interrupted during processing on the receiving side.
  • the time stamp given to the packet is compared with the current time, so that the packet can be received at a time that can be reproduced on the receiving side. Let the user determine whether the packet is a packet or not.
  • Japanese Patent Application Laid-Open No. 2000-216816 discloses a method of comparing a packet time stamp with the current time and stopping retransmission control if the delay is equal to or greater than a specified value. I have. However, in any of the above methods, a complicated time comparison must be performed to control the discard of buckets from the transmission buffer by checking the playback time on the receiving side, and the circuit scale is large. It will be connected. Also, with reference to Japanese Patent Application Laid-Open No. 2000-212816, if the delay of an arbitrary packet increases, the retransmission control stops, and the state of an error occurring in the transmission process is reduced. It is difficult to know exactly. Disclosure of the invention
  • the present invention does not have a complicated circuit configuration when transmitting continuously processed data such as a video signal and an audio signal using a communication transmission line having an error.
  • Another object of the present invention is to provide a data communication method and a data transmission device capable of discarding a bucket that has become too late for the reproduction time on the receiving side.
  • a data communication method comprises: a data transmission device having a buffer for storing data for each first data unit; and a data reception device for receiving data transmitted by the data transmission device.
  • a data communication method in which the data transmitting device confirms data requested by the data receiving device to retransmit, wherein the data transmitting device checks the data stored in the buffer in the data transmitting device.
  • the data receiving apparatus is provided with the number of retransmissions, which is information indicating whether retransmission is possible or not. Changing the number of retransmissions assigned to each of the data stored in the buffer, and discarding the data for each of the first data units for the number of retransmissions exceeding a predetermined value from the buffer.
  • a trigger is generated at a predetermined timing, and the number of retransmissions of the data stored in the buffer is subtracted or added by one, and the number of retransmissions is calculated. It is checked whether the specified value has been reached. In this way, by monitoring the number of retransmissions of each data in the first data unit, it is possible to easily confirm that the data cannot be reproduced by the data receiving device. Therefore, it is possible to simplify the process of discarding a packet that has been confirmed to be unreproducible from the buffer.
  • a data communication method includes a data transmission device having a buffer for storing data for each first data unit, and a data reception device for receiving data transmitted by the data transmission device.
  • the data receiving apparatus For each data unit, the data receiving apparatus is provided with the number of retransmissions, which is information indicating whether or not retransmission is possible, and at predetermined timing, the data allocated to the data stored in the buffer is given.
  • the number of retransmissions is changed, and when the number of retransmissions for each of the first data units stored in the buffer exceeds a reference value, it is confirmed that a communication error has occurred and the amount of data to be transmitted. It is characterized by the following.
  • the data transmission device can easily confirm the state of the communication path with the data reception device by comparing the average value of the number of retransmissions of the data in the buffer with the reference value.
  • the data communication method of the present invention comprises: a data transmitting device having a buffer for storing data for each first data unit; and a data receiving device for receiving data transmitted by the data transmitting device.
  • the data receiving device confirms data requested to be retransmitted by the data transmitting device, wherein the data transmitting device stores the data in the buffer.
  • data is given a number of retransmissions, which is information indicating whether retransmission is possible to the data receiving apparatus.
  • Data stored in the buffer is given at predetermined timings Changing the number of retransmissions assigned to each of the data transmission devices, when the number of retransmissions for each of the first data units transmitted during the transmission period assigned to the data transmission device exceeds a reference value, It is characterized by confirming that the communication is abnormal and reducing the amount of data to be transmitted.
  • the data transmission device can easily confirm the state of the communication path with the data reception device by comparing the average value of the number of retransmissions of the data transmitted to the data reception device with the reference value.
  • a data communication method includes a data transmission device having a buffer for storing data for each first data unit, and a data reception device for receiving data transmitted by the data transmission device.
  • the data transmitting apparatus can easily determine the state of the communication path with the data receiving apparatus by comparing the amount of data discarded during a predetermined period, such as the generation cycle of the timing for subtracting the number of retransmissions, with the reference value. You can check.
  • the data communication device of the present invention includes a buffer for storing data for each first data unit, a transmitting unit for transmitting the data stored in the buffer, and a data receiving device for receiving the data.
  • a receiving unit that receives a reception acknowledgment signal notifying a reception state; and confirming a reception state of the data reception device based on the reception acknowledgment signal received by the reception unit.
  • a retransmission request analysis unit for recognizing, and for the data stored in the buffer, for each second data unit, a retransmission possible number serving as information indicating whether retransmission is possible to the data receiving apparatus.
  • a transmission data management unit for discarding data in the buffer and controlling input / output of the data, wherein the retransmission possible number management unit checks the value of the retransmission possible number.
  • the control unit changes the number of retransmissions assigned to each of the data stored in the buffer at each predetermined timing, and the transmission data management unit changes the number of retransmissions that exceeds a predetermined value.
  • the data for each of the first data units is confirmed and discarded from the buffer.
  • the data communication device of the present invention includes a buffer for storing data for each first data unit, a transmitting unit for transmitting the data stored in the buffer, and a data for receiving the data.
  • a receiving unit that receives a reception acknowledgment signal for notifying a reception state of the reception device; and a reception status of the data reception device based on the reception acknowledgment signal received by the reception unit.
  • a retransmission request analysis unit for recognizing data to be transmitted, and a retransmission capability serving as information indicating whether retransmission can be performed to the data receiving apparatus for each second data unit with respect to data stored in the buffer.
  • a transmission data management unit for confirming whether a communication error, in the allowable number of retransmissions management unit, at predetermined timing, stored in the buffer The number of retransmissions assigned to each of the data to be transmitted is changed by the transmission data management unit, and the number of retransmissions for each of the first data units stored in the buffer is set to a reference value. When the number exceeds the limit, it is confirmed that the communication is abnormal, and the amount of data to be transmitted is reduced.
  • the data communication device of the present invention includes a buffer for storing data for each first data unit, a transmitting unit for transmitting the data stored in the buffer, and a data receiving device for receiving the data.
  • a receiving unit that receives a reception acknowledgment signal for notifying the reception status of the data reception device; and a reception status of the data reception device based on the reception acknowledgment signal received by the reception unit.
  • a retransmission request analysis unit for recognizing the number of retransmissions, which is information indicating whether retransmission is possible to the data receiving apparatus for each second data unit for data stored in the buffer.
  • a retransmission count management unit for checking the value of the retransmission count, and a data transmission unit for each of the first data units transmitted during a transmission period allocated to the data transmission device.
  • a transmission data management unit that checks whether or not the communication is abnormal based on the number of retransmissions that can be performed.
  • the transmission data management unit stores the data in the buffer at predetermined times at the retransmission possible number management unit.
  • the retransmittable number of times assigned to each of the data is changed, and the transmission data management unit applies the data to each of the first data units transmitted during the transmission period assigned to the data transmission device.
  • the number of retransmissions exceeds a reference value, it is confirmed that a communication error has occurred and the amount of data to be transmitted is reduced.
  • the data communication device of the present invention includes a buffer for storing data for each first data unit, a transmitting unit for transmitting the data stored in the buffer, and a receiving unit for receiving the data.
  • a receiving unit for receiving a reception confirmation signal for notifying a state; and confirming a reception state of the data reception device based on the reception confirmation signal received by the reception unit, and recognizing data requested by the data reception device for retransmission.
  • a retransmission request analysis unit for performing the retransmission request count, which is information indicating whether retransmission is possible to the data receiving apparatus for each second data unit, for the data stored in the buffer.
  • the transmission data management unit checks the data for each of the first data units for the number of retransmissions that exceeds a predetermined value, and discards the data from the buffer. When the amount of data discarded from the buffer exceeds the reference value, it is confirmed that a communication error has occurred and the amount of data to be transmitted is reduced.
  • FIG. 1 is a block diagram illustrating an internal configuration of a data transmission device in the communication system according to the first embodiment
  • FIG. 2 is a flowchart showing the bucket discard control operation of the data transmitting apparatus of FIG. 1,
  • FIG. 3 is a flowchart showing a transmission control operation of the data transmission device of FIG. 1,
  • FIGS. 4A and 4B are diagrams showing the format of a packet transmitted from the data transmitting apparatus
  • FIG. 5 is a block diagram showing an internal configuration of a data transmission device in the communication system of the second embodiment
  • FIG. 6 is a flowchart showing the transmission control operation of the data transmission device of FIG.
  • FIG. 7 is a block diagram showing an internal configuration of a data transmission device in the communication system according to the third embodiment.
  • FIG. 8 is a flowchart showing a transmission control operation of the data transmission device of FIG. 7,
  • FIG. 9 is a block diagram showing another example of the internal configuration of the data transmission device in the communication system according to the third embodiment.
  • FIG. 10 is a block diagram showing another example of the internal configuration of the data transmission device in the communication system according to the third embodiment.
  • FIG. 11 is a block diagram showing the internal configuration of a data transmission device in a conventional communication system. It is a lock diagram,
  • FIG. 12 is a flowchart showing a bucket discarding control operation of the conventional data transmitting apparatus.
  • FIG. 13 is a flowchart showing a transmission control operation of the conventional data transmission device.
  • FIG. 1 is a block diagram showing an internal configuration of a data transmission device used in the communication system of the present embodiment.
  • a device in which data is externally input to a data transmission device will be described as an example.
  • the data transmission device includes a recording medium for storing data to be transmitted and is recorded on a recording medium such as a hard disk or an optical disk. It may be a data transmission device that transmits data.
  • the data transmitting apparatus 101 shown in FIG. 1 includes a sequence number adding section 1 for adding input data to each packet with a sequence number, and a time for adding a time stamp serving as a reproduction time to each packet.
  • a stamp addition unit 2 a retransmission possible number management unit 3 that manages the number of retransmissions possible for each packet, a transmission data management unit 4 that manages transmission data, and a bucket to which a sequence number and a time stamp are added
  • a transmission buffer 5 for temporarily storing data
  • a reception unit 6 for receiving a signal indicating the reception state of the reception side
  • a retransmission request analysis unit 7 for confirming a packet requested to be retransmitted by the reception side
  • a transmitting unit 8 for transmitting a packet to the receiving side, an error correcting code adding unit 9 for adding an error correcting code to a packet read from the transmitting buffer 5, and an antenna 10 for transmitting and receiving data. It is.
  • the sequence number adding unit 1 adds a sequence number that is incremented for each packet for each input packet. .
  • the packet to which the sequence number is added is given to the time stamp adding unit 2, and a time stamp serving as information on the reproduction time on the receiving side is added. This sequence number and timestamp
  • the packet to which is added is temporarily stored in the transmission buffer 5.
  • the retransmission allowable number management unit 3 is given the sequence number added to the packet by the sequence number addition unit 1. Then, after the transmission period set for the data transmitting apparatus 101 is started, information on the reproduction time on the receiving side for the packet of the sequence number given first is confirmed. The difference between the confirmed playback time and the time input to the data transmission device 101 is divided by the period of the transmission period set for the data transmission device 101, so that the Information on the number of retransmissions is set, and is stored in the retransmission number management unit 3. Then, each time a packet is input to the data transmitting apparatus 101 and the sequence number added to the bucket is given to the retransmittable number management unit 3, the held retransmittable number is added.
  • a reception confirmation signal such as an ACK signal indicating the reception status of the transmitted packet on the reception side or a transmission period start signal transmitted from a control station or the like indicating the start of a set transmission period. Is received via the antenna 10.
  • the data transmitting apparatus 101 recognizes the start of the set transmission period by receiving the transmission period start signal, but the period of the set transmission period is set in advance.
  • the start of the transmission period may be recognized each time the period of the transmission period is detected by a timer or the like provided from a control station or the like.
  • the reception unit 6 receives the transmission period start signal and confirms the start of the transmission period, the remaining retransmission possible number value of each sequence number recorded in the retransmittable number management unit 3 is incremented by one. Decrement by. Then, when the number of retransmittable times added to each sequence number is decremented, retransmittable number management section 3 confirms a sequence number in which the value of the retransmittable number has become equal to or less than a specified value.
  • the transmission data management unit 4 is notified of the sequence number for which the value of the number of retransmissions becomes equal to or less than the specified value, and the transmission data management unit 4 transmits the packet corresponding to the sequence number notified from the retransmission possible number management unit 3. Discard the packet from transmit buffer 5. The retransmittable number management unit 3 deletes the sequence number of the packet discarded from the transmission buffer 5 from the record.
  • the above-mentioned specified value is a reference value for determining whether or not to prohibit the transmission of the packet on the transmitting side. In the present embodiment, the specified value is set to 0. Shall be.
  • the retransmission count management unit 3 monitors the remaining retransmission count added to each held sequence number, and stores it in the transmission buffer 5 when confirming that the transmission period has started. The average value of the number of resend times of the packet is calculated. Then, the transmission data management section 4 determines whether or not the transmission is abnormal, based on whether or not the average value of the number of retransmissions is equal to or less than the reference value. At this time, if the average value of the obtained number of retransmissions is equal to or less than the reference value, it is determined that the transmission is abnormal.
  • the retransmission request analysis unit 7 notifies the transmission data management unit 4 of information on the packet to be retransmitted by analyzing the reception status on the receiving side from the reception confirmation signal received by the reception unit 6. At this time, the retransmission request analysis unit 7 confirms the bucket normally received on the receiving side from the reception confirmation signal, and notifies the transmission data management unit 4 of the sequence number.
  • the transmission data management unit 4 is notified of the sequence number indicating the packet normally received on the receiving side, the packet of the notified sequence number is discarded from the transmission buffer 5. Thereafter, when the start of the transmission period is confirmed and the transmission period starts, the transmission data management unit 4 determines whether or not the transmission is abnormal, and holds the transmission buffer 5 in the transmission buffer 5 according to the determination.
  • the packet to be transmitted is searched from the retransmitted packet and the new packet.
  • the packet is stored in the transmission data management unit 4 and transmitted from the transmission buffer 5 to the error correction code adding unit 9 while controlling so as not to exceed the set transmission period.
  • the output of the packet to be transmitted is controlled.
  • the packet output from the transmission buffer 5 is provided to an error correction code adding unit 9 and added with an error correction code as described later, and then transmitted by the transmission unit 8 to the receiving side via the antenna 10. .
  • FIGS. 4A and 4B are diagrams showing the format of each packet in the data transmitted in real time from the transmission unit 8.
  • the packet shown in FIG. 4A is composed of a header 51 containing information such as configuration conditions in the packet, a sequence number 52 and a time stamp 53 added to the packet.
  • the packet is composed of data 54 such as video signals and audio signals included in the packet, and an error correction code 55, and has a configuration in which an error correction code is added for each packet.
  • One packet may be provided with one correction code as in the format shown in FIG. 4A, but as shown in FIG. 4B, the header 15 1 and the sequence number 5 2 and time stamp 53 and data 54 are divided into a plurality of blocks B1 to Bn, and error correction codes b1 to b ⁇ are added to each block B1 to Bn. I do not care.
  • the bucket discard control operation in the data transmitting apparatus 101 having such a configuration will be described with reference to the flowchart in FIG.
  • the receiving unit 6 receives the transmission period start signal and confirms the start of the transmission period, the transmission period starts, and the start of the transmission period is notified to the retransmission possible number management unit 3 to start the packet discard control operation. (S 1).
  • the retransmittable number management unit 3 decrements the value of the remaining retransmittable number added to the held sequence number of each packet by one (S 2), and stores it in the transmission buffer 5.
  • the sequence number to which the number of retransmissions that is less than the specified value is added is notified to the transmission data management unit 4, and the transmission data The packet corresponding to the sequence number notified by the management unit 4 is discarded from the transmission buffer 5 (S4). Then, the sequence number of the next oldest packet among the packets stored in the transmission buffer 5 is confirmed (S5), and the process proceeds to S3.
  • the transmission control operation in the data transmitting apparatus 101 will be described with reference to the flowchart in FIG.
  • the receiving unit 6 receives the transmission period start signal and confirms the start of the transmission period, the transmission period starts and the transmission control operation starts (
  • the retransmission request analysis unit 7 performs a normal retransmission control by the transmission data management unit 4.
  • the retransmitted packet confirmed in and the new packet to be newly transmitted are searched (S13).
  • the retransmission control operation is stopped (S14), and the transmission data management is performed.
  • a new bucket to be newly transmitted is searched (S15).
  • the remaining It can be checked simply by managing the number of retransmissions.
  • the bucket can be discarded by managing the remaining number of resends, so even if the communication path condition deteriorates and the resend capability becomes limited, the resend operation is stopped and the bucket is greatly sent. By discarding from the buffer, quick error recovery can be performed.
  • a new bucket to be newly transmitted is searched for in S15 of the transmission control operation in FIG. 3, but the specified value of the remaining number of retransmissions to be discarded is newly set to a large value. Then, after discarding from the transmission buffer 5 those packets whose remaining number of retransmissions is less than or equal to the newly set specified value from the retransmission packet and the new packet, the remaining number of retransmissions becomes the maximum.
  • Such a retransmission bucket and a new bucket may be searched.
  • FIG. 5 is a block diagram showing an internal configuration of a data transmission device used in the communication system of the present embodiment.
  • the data transmitting apparatus shown in FIG. 5 parts used for the same purpose as the data transmitting apparatus shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.
  • the data transmission device of FIG. 5 similarly to the first embodiment, performs the discard control operation of the packet in the transmission buffer 5 according to the flowchart of FIG. Data having a configuration as shown in FIGS. 4A and 4B is transmitted from the transmission unit 8 via the antenna 10.
  • the data transmission device 102 in FIG. 5 is provided in the data transmission device 101 in FIG.
  • a priority adding unit 11 for adding a transmission priority to a packet to which a sequence number is added is provided.
  • the transmission priority is set, for example, according to the type of data included in a packet such as text data, video data, or audio data, or whether the data in the packet is synchronous or asynchronous. And shall be given by a numerical value. Also, the higher the numerical value given as this priority, the higher the priority.
  • the sequence number is added to the packet input to the data transmitting apparatus 102 having such a configuration by the sequence number adding unit 1 as in the data transmitting apparatus 101 of FIG. Then, the packet to which the sequence number is added is given to the priority adding section 11 and the priority is added. Then, the time stamp is added in the time stamp adding section 2 and stored in the transmission buffer 5. .
  • the transmission data management unit 4 determines whether or not the transmission is abnormal, and, in accordance with this determination, considers the priority from the retransmission bucket held in the transmission buffer 5 and the new bucket. Search for packets to send. Then, the sequence number of the retrieved bucket is stored in the transmission data management unit 4, and the output control of the bucket is performed on the transmission buffer 5 while managing the transmission sequence so as not to exceed the transmission period.
  • the operation of the other blocks in the data transmission device 102 is the same as the operation of the data transmission device 101 in the first embodiment, and a detailed description thereof will be omitted.
  • the transmission control operation in the data transmission device 102 having such a configuration will be described with reference to the flowchart in FIG.
  • steps that perform the same operations as in the flowchart of FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.
  • the receiving unit 6 receives the transmission period start signal and confirms the start of the transmission period, and starts the transmission control operation (S11), it is determined whether or not the transmission is abnormal according to the average value of the number of remaining retransmissions. Is determined (S12).
  • a retransmission bucket to be transmitted and a new bucket are searched (S13).
  • the priority added to each of the retransmission packet and the new packet is checked, and the packet whose priority is equal to or more than the specified value is determined.
  • a bucket to send (S21).
  • the sequence proceeds to S16 and stores the sequence number of the packet to be transmitted.
  • the packet is transmitted by repeating the operations of S17 to S19 until the transmission time has expired or the transmission period has almost ended.
  • a search is made for a packet having a high priority from the retransmission packet and the new packet. Similar to the embodiment, after stopping the retransmission control as in S14 in the flowchart of FIG. 3, control is performed in S21 to search for a high-priority packet from among the new packets. It does not matter.
  • FIG. 7 is a block diagram showing the internal configuration of the data transmission device used in the communication system of the present embodiment. Note that, in the data transmission device of FIG. 7, parts used for the same purpose as in the data transmission device of FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. Also, in the present embodiment, as in the first embodiment, the data transmission device of FIG. 7 performs the discard control operation of the packet in the transmission buffer 5 according to the flowchart of FIG. The data having the configuration as shown in FIG. 4B is transmitted from the transmission unit 8 via the antenna 10.
  • the data transmission device 103 of FIG. 7 adjusts the amount of packets input to the data transmission device 103 in addition to the blocks provided in the data transmission device 101 of FIG.
  • the bucket amount adjusting unit 12 for example, when the data supplied to the data transmitting device 101 is AV data, and when the communication path condition is good, high-definition HDTV AV data is transmitted. Thus, all buckets input from the outside are output to the subsequent block.
  • the bit-rate is higher than the standard HDTV AV data.
  • the packet amount adjustment unit 12 thins out packets input from the outside and outputs the data to the subsequent block so that AV data for SDTV with low data rate is transmitted.
  • the packet amount adjustment unit 12 In this case, the amount of input packets may be adjusted by thinning out packets containing data that is not necessary for reproduction.
  • the packet input to the data transmitting apparatus 103 having such a configuration is adjusted by the packet amount adjusting unit 12 to a packet amount according to the communication path state, and is provided to the sequence number adding unit 1.
  • the packet given to the sequence number adding unit 1 is stored in the transmission buffer 5 after the sequence number and the time stamp are added in order similarly to the data transmitting apparatus 101 of FIG.
  • the transmission data management unit 4 determines whether or not the transmission is in an abnormal state, and determines whether or not to adjust the amount of the inputted bucket by the bucket amount adjustment unit 12 according to the determination. .
  • the packet amount reduced by the thinning rate in the packet amount adjustment unit 12 is used. Search for a packet. Therefore, for example, when the thinning rate is 1/2, when the sequence number stored in the transmission data management unit 4 during a normal transmission operation is a continuous number from 1 to 100, the packet amount When the thinning operation is performed by the adjustment unit 12, the sequence numbers stored in the transmission data management unit 4 are 1 to 50.
  • the operation of the other blocks in the data transmission device 103 is the same as the operation of the data transmission device 101 in the first embodiment, and a detailed description thereof will be omitted.
  • the transmission control operation in the data transmission device 103 having such a configuration will be described with reference to the flowchart in FIG.
  • steps that perform the same operations as those in the flowchart of FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.
  • the receiving unit 6 receives the transmission period start signal and confirms the start of the transmission period, and starts the transmission control operation (S11), it is determined whether or not the transmission is abnormal according to the average value of the number of remaining retransmissions. Is determined (S12). At this time, if it is determined that the transmission is not abnormal (No), a retransmission packet to be transmitted and a new packet are searched (S13).
  • the packets are thinned out in the packet amount adjustment unit 12 so that the packet amount given to the sequence addition unit 1 is reduced. Adjusted (S31). Further, at this time, the thinning rate in the packet amount adjustment unit 12 is given to the transmission data management unit 4.
  • the transmission data management unit 4 sets the amount of packets to be transmitted based on the given thinning rate, and transmits a retransmission packet and a new packet according to the amount of packets. Is searched (S32). In this way, after searching for packets to be transmitted in S13 and S32, the sequence proceeds to S16 to store the sequence number of the packet to be transmitted. The packet is transmitted by repeating the operations of S17 to S19 until the transmission period is almost completed.
  • the packet amount adjustment unit 12 controls the data transmission device 103 By reducing the amount of data to be processed in, for example, when transmitting AV data, it is possible to prevent frequent interruption of video and audio.
  • transmission is performed from only the new bucket in S32. It may be controlled to search for the packet to be used.
  • the packet adjusting unit 12 is provided before the sequence number adding unit 1, but as in the data transmitting device 104 of FIG.
  • the packet adjusting unit 12 may be provided between the time stamp adding unit 2 and the transmission buffer 5. By doing so, it is possible to search for a packet to be transmitted without giving the thinning rate in the bucket adjustment unit 12 to the transmission data management unit 4.
  • the sequence number stored in the transmission data management unit 4 when performing a normal transmission operation is a sequence of 1, 2, 3, ..., 100
  • the packet amount adjusting unit 12 sets the sequence number 2, 4, 6, 6,... Are stored in the transmission buffer 5 after being decimated, the sequence numbers stored in the transmission data management unit 4 are 1, 3, 5,...
  • the data transmitting device is provided between the time stamp adding unit 2 and the bucket amount adjusting unit 12.
  • the priority adding unit 11 may be provided. This priority adding section 11 is the same as that provided in the data transmitting apparatus 102 of the second embodiment (FIG. 5). By doing so, when performing the thinning operation in the packet amount adjusting unit 12, based on the priority added by the priority adding unit 11, the bucket with a priority lower than the predetermined value is thinned out. Output to transmission buffer 5.
  • the operation of decrementing the remaining number of retransmissions allowed in S2 is that a certain period of time has elapsed after the end of transmission, or the start of the transmission period. It may be performed by confirming any of the above, or by confirming the elapse of a certain period of time after the end of transmission, regardless of whether the transmission period has been confirmed or not.
  • an abnormal state is determined by using the average value of the number of retransmissions of the packet stored in the transmission buffer 5, but the number of retransmissions of the actually transmitted packet is determined.
  • the average value may be used to determine an abnormal state.
  • the retransmission request analysis unit 7 counts the number of serial numbers notified to the transmission data management unit 4 when the value of the number of retransmissions becomes equal to or less than the specified value. Then, the number of counted serial numbers is given to the transmission data management unit 4, and when the number of serial numbers exceeds the reference value (that is, the amount of discarded packets exceeds the reference value). ), It is determined that the transmission is abnormal.
  • the packet amount of the discarded packet for determining the abnormal transmission state may be the packet amount of the packet discarded at the start of the transmission period, or may be the packet amount counted at the predetermined period. I do not care.
  • the average value of the number of retransmissions that can be confirmed to be in the transmission abnormal state when operating in the normal state or the reference value for the discarded packet amount is used as the first reference value
  • the average value of the number of resends or the reference value for the amount of discarded packets, which confirms that the communication path has been improved when operating in the abnormal transmission state is used as the second reference value.
  • the reference values may be different.
  • the relationship between the first and second reference values with respect to the average value of the number of retransmissions is set as the second reference value> the first reference value, and the first and second reference values with respect to the amount of discarded packets.
  • the relationship is: 1st reference value> 2nd reference value.
  • an error detection code addition unit that adds an error detection code may be used instead of the error correction code addition unit 9.
  • each data of the packet Is added with an error detection code.
  • a sequence number follows one header as in the bucket in FIG. 4A or FIG. 4B. The sequence number may be included.
  • the time stamp may not be included in the bucket, and the time stamp may be used only for management in the data transmission device.
  • reception confirmation signal an ACK signal indicating a packet correctly received on the receiving side, a NACK signal indicating a packet not received on the receiving side, or the like may be used.
  • the description has been given based on an example of use for a wireless communication system using an antenna, the present invention may be used for a wired communication system such as a power line communication system using a power line or a communication system using a cable line. 'Further, in each of the above-described embodiments, the number of retransmittable times of each packet is set by dividing the difference between the reproduction time and the time input to the data transmission device by the set transmission period.
  • the type of data of each packet may be determined, and the number of retransmissions determined in advance by the data transmitting apparatus may be set for each type.
  • the number of retransmissions allowed for a packet based on AV data is predetermined as Nx and the number of retransmissions available for a packet based on text data is predetermined as Ny
  • the bucket input to the device is AV data, set the number of retransmissions as NX
  • the bucket input to the data transmission device is text data, set the number of retransmissions as Ny.
  • the number of retransmissions given to the packet is decremented, and the value becomes equal to or less than the specified value.
  • the transmission period start signal is received and the start of the transmission period is confirmed, the number of retransmissions given to the packet is incremented and the value is set to the specified value. In this case, the packet may be discarded.
  • the average value of the number of retransmissions possible for the packet stored in the buffer when the average value of the number of retransmissions exceeds the reference value, it is determined that the transmission is abnormal. Is done. When judging from the average value of the number of resend times of transmitted packets, It is determined that the transmission is abnormal when the average of the number of possible times exceeds the reference value.
  • ADVANTAGE OF THE INVENTION by monitoring the number of retransmissions given for each bucket of data, it is possible to discard the bucket that is not in time for the reproduction time in the data receiving device and check the communication abnormal state. . Therefore, unlike the conventional case, the comparison between the reproduction time and the current time is not always performed by the data transmission device, and the bucket is easily discarded and the abnormal communication state is confirmed only by the number of retransmissions possible.
  • the circuit configuration in can be simplified.
  • quick error recovery can be achieved by stopping retransmission control.
  • the data transmission device is provided with a priority addition unit to add a priority to each packet of data, and according to the added priority, when a communication error condition is detected, the priority is increased from the highest priority. Can be sent.
  • a data receiving device that receives data can perform reproduction such that interruption of data is felt as little as possible.
  • the data transmission device may be provided with a packet amount adjusting unit to start control to reduce the amount of data given to the buffer when a transmission error occurs, thereby reducing the packet amount of data to be transmitted. it can.
  • data other than the minimum data required for reproduction is thinned out by the packet amount adjustment unit, so that the data receiving device that receives data can perform reproduction that makes the data interruption as small as possible. it can.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Detection And Prevention Of Errors In Transmission (AREA)
  • Communication Control (AREA)

Abstract

Dans cette invention, le nombre des séquences de paquets mémorisés dans un tampon de transmission (5) est appliqué à une unité (3) de gestion de nombre possible de retransmissions. Le nombre possible de retransmissions, qui est abaissé chaque fois que la période de transmission commence, est ajouté à chaque nombre de séquences. Lorsqu'on détermine que ce nombre possible de retransmissions est égal ou inférieur à une valeur prédéterminée, une unité (4) de gestion des données de transmission élimine du tampon de transmission (5) le paquet qui correspond au nombre de séquences ainsi déterminé. Lorsque la moyenne des nombres possibles de retransmissions des paquets mémorisés dans le tampon de transmission (5) est égale ou inférieure à une valeur de référence, on détermine qu'un état anormal de communication s'est produit.
PCT/JP2003/006899 2002-06-07 2003-05-30 Procede de communication de donnees et appareil de transmission de donnees WO2003105420A1 (fr)

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JP2004512359A JP4033860B2 (ja) 2002-06-07 2003-05-30 データ通信方法及びデータ送信装置
AU2003244101A AU2003244101A1 (en) 2002-06-07 2003-05-30 Data communication method and data transmission apparatus

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Publication number Priority date Publication date Assignee Title
JP2007517458A (ja) * 2003-12-29 2007-06-28 エレクトロニクス アンド テレコミュニケーションズ リサーチ インスチチュート 移動通信システムにおけるパケット再送方法及びそのプログラムが記録されたコンピュータで読取り可能な記録媒体
JP4668207B2 (ja) * 2003-12-29 2011-04-13 エレクトロニクス アンド テレコミュニケーションズ リサーチ インスチチュート 移動通信システムにおけるパケット再送方法及びそのプログラムが記録されたコンピュータで読取り可能な記録媒体
JP4574402B2 (ja) * 2005-03-10 2010-11-04 富士通株式会社 非同期データのタイムスタンプ生成機能を有する無線装置
JP2006253986A (ja) * 2005-03-10 2006-09-21 Fujitsu Ltd 非同期データのタイムスタンプ生成機能を有する無線装置
JP2007066076A (ja) * 2005-08-31 2007-03-15 Canon Inc サーバ装置及びイベント通知方法
US8412997B2 (en) 2006-03-30 2013-04-02 Alibaba Group Holding Limited Method and system for message retransmission and intersystem message delivery
WO2007112667A1 (fr) * 2006-03-30 2007-10-11 Alibaba Group Holding Limited procédé et appareil pour la transmission de message, procédé et appareil pour la notification de messages inter-systèmes
US8009596B2 (en) 2006-11-30 2011-08-30 Kabushiki Kaisha Toshiba Data transmitting apparatus, data receiving apparatus, and data communication system
JP2009141836A (ja) * 2007-12-10 2009-06-25 Advanced Telecommunication Research Institute International 無線装置およびそれを備えた無線ネットワーク
CN101904197A (zh) * 2007-12-20 2010-12-01 株式会社Ntt都科摩 移动台、基站装置、通信控制方法以及移动通信系统
JP2012034407A (ja) * 2007-12-20 2012-02-16 Ntt Docomo Inc 移動局、基地局装置、通信制御方法及び移動通信システム
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JP2015050674A (ja) * 2013-09-03 2015-03-16 国立大学法人東北大学 無線通信システムおよび無線通信方法

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