JP5240285B2 - Retransmission device when communication is abnormal - Google Patents

Description

  The present invention relates to a network communication processing apparatus in wireless communication using a cellular phone network.

In conventional network communication, since communication is performed using a dedicated line, network communication is performed with the communication line connected, and it is necessary to consider the amount of communication depending on the communication performance requirement. Also, the communication method using a dedicated line has a problem that the initial introduction cost is high and the running cost is high.

  In recent years, public infrastructures such as public lines, wide area networks, and mobile phone networks have been used as a means to reduce initial installation costs and running costs. In network communications using such public infrastructures, in order to keep communication charges low In addition, as a method of communication connection, devices such as disconnecting the line or reducing the amount of packet communication are performed except when information is transmitted and received.

  This communication connection method is such that the communication line is connected only when an information transmission / reception request is generated, and the communication line is disconnected when transmission / reception is completed. In order to suppress the frequency of information transmission / reception, the information transmission source (terminal device etc. ) Is also used, such as transmitting information to an information transmission destination (server device or the like) after storing the information. Regarding the reduction of the packet communication amount, the amount of packet is reduced by methods such as simplifying transmission data or eliminating the arrival confirmation of transmission data.

  In the case of plant monitoring, the type of information is also classified into fixed period data that is continuously transmitted at a constant period, such as measurement values, and event data that is transmitted when an event occurs. As shown in FIG. 7, data transmission of the fixed period data 81, 82, and 83 is continued at the fixed period interval of T1, and the fixed period data is T1 + T2 obtained by adding a sufficient delay time T2 to T1 on the receiving side. The reception status of the periodic data is monitored with a timeout timer. If the periodic data 83 is not received due to some failure and a timeout occurs, a retransmission request 84 is transmitted from the receiving side to the transmitting side. However, there is a possibility that old data may be transmitted due to a large transmission delay, and depending on the contents of the data, there may be no problem with the next periodic data, but when the information has not been reached, the retransmission request itself has not been reached. There was a problem such as high possibility of becoming.

  As shown in FIG. 8, the event data is a communication number (hereinafter referred to as a serial number) that is updated by adding +1 as N, N + 1, N + 2 each time event data 91, 92, 93 is transmitted on the transmission side. ), And the receiving side monitors the serial number N + 1 added to the previously received serial number N, and if there is a mismatch between the expected value and the serial number check of the event data 94 received this time, Here, a retransmission request 95 of serial numbers (N + 1) to (M-1) is made. However, this retransmission request has a problem in that it cannot be recognized until the next event data is received.

  A method of performing data communication by adding a serial number to the transmission data is known in Patent Document 1, and according to Patent Document 1, data transmitted on the transmission side is divided into partial data and Send the partial data with a serial number according to the transmission order, and on the receiving side, check for data error for each serial number and partial data, send back information about the check result to the transmitting side, It is shown in the form of execution.

JP 05-136664 A

  As shown also in this Patent Document 1, in data transmission configured on the transmission side and the reception side via the data transmission path, there is no guarantee that the data on the transmission side will surely reach the reception side, and there is always some kind of retransmission means However, in order to keep the number of communications low, this retransmission means must be implemented so that the reduction in communication efficiency is minimized.

  Therefore, the object of the present invention is to change the retransmission request method and connect the line only when transmitting and receiving information as a communication connection method in order to keep the communication fee low in network communication using public infrastructure. An object of the present invention is to provide an inexpensive communication method with a reduced communication amount and a good communication efficiency.

The periodic transmission data transmitted from the data transmission device via the network at a constant cycle and the event data transmitted when the event occurs are transmitted to the data reception device. In a network transmission system that performs a retransmission request for missing data,
Means for adding a periodic sequence number that is updated by +1 for each transmission of the periodic data to the data transmission device;
And means for adding each event serial number is updated by +1 every transmission of the event data,
Means for transmitting each fixed cycle data by adding a transmitted event sequence number generated immediately before transmission of the fixed cycle data;
When the arrival confirmation signal of the transmitted event data is not returned within the determined time from the data receiving device, the event data is retransmitted, and a means for disconnecting the line as a retry over after a predetermined number of retransmissions is provided,
Means for returning an event data arrival confirmation signal to the data transmitter;
Each time event data is received, the event sequence number received last time is compared with the event sequence number received this time, and when the event sequence number is discontinuous, it is determined that event data is missing and Provide a means for requesting retransmission,
The data transmitting device is configured to retransmit the missing data when a retransmission request is received from the data receiving device .

As described above, according to the present invention, it is possible to reduce the number of communication lines and the amount of communication packets without reducing the quality of communication data in communication using a public infrastructure such as a public line, a wide area network, and a mobile phone network. Communication charges can be reduced.

Network configuration diagram of the present invention Periodic data retransmission processing according to Embodiment 1 of the present invention Retransmission processing of event data according to embodiment 2 of the present invention Retransmission processing of event data using fixed period data according to Embodiment 3 of the present invention Periodical information failure management Request to resend event information due to missing serial number in host device Conventional periodic data re-transmission processing Conventional event data resend processing

  FIG. 1 is a network configuration diagram of the present invention. Reference numeral 1 denotes a network, 2 denotes a lower level device, and 5 denotes a higher level device. The lower level device 2 and the higher level device 5 are connected via an uplink information transmission device 3, a network 1, and a downlink information transmission device 4 to perform data transmission. As described above, the communication information from the lower apparatus 2 to the upper apparatus 5 includes fixed period data for transmitting data at a fixed period and event data for transmitting data at any time. The processing methods of the lower device 2 and the upper device 5 for these two types of transmission data are shown below.

  As for the communication error detection method, if the periodic data does not reach the data within the timeout timer, it is judged that the data has not been reached. However, when this data failure is detected, it is only stored as an error log (reports an error when necessary). No retransmission request is made here. Since event data is transmitted at any time, it is not possible to detect data unreachable by a timer on the receiving side. For this reason, the missing number is determined by serial number, but since event data is transmitted at any time, it is delayed in time to receive the next event data, so use event serial number notification or periodic data. To detect missing event data.

  As for the re-transmission processing method, as described above, the fixed-cycle data is not executed when the data is not reached by the timeout timer. The received periodic periodic sequence number +1 is compared with the periodic periodic sequence number received this time. For event data, compare the event data and the event number notification sequence number (hereinafter referred to as the event sequence number) with the received event sequence number +1, or the sent event sequence number newly added to the periodic data and the received event sequence number at the receiving side. If they do not match, a retransmission request for missing data is made.

  FIG. 2 shows a periodic data retransmission process according to the first embodiment of the present invention. The periodic data 11, 12, 13,... Are sequentially added from the transmitting side to the receiving side at regular intervals of T1, and the periodic numbers L, L + 1, L + 2,. It is stored and updated sequentially in the memory as a cyclic serial number. Here, for example, after receiving the data 11 of the fixed cycle serial number L, it is assumed that the data 12 and 13 of the fixed cycle serial numbers L + 1 and L + 2 are lost for some reason and are normally received from the data 14 of the next fixed cycle serial number L + 3. The receiving side makes a retransmission request to the transmitting side as follows.

  The data 11 of the fixed cycle serial number L is received, and the receiving side stores L in the memory as the received fixed cycle serial number. After that, if the next fixed period data 12 to be received is not received even after the timeout timer T1 + T2 has elapsed, the data is recognized as unsuccessful communication, but at this point in time, without a retransmission request, Save it in memory as an error log that reports error information when necessary.

  Since the data 14 of the next fixed-cycle serial number L + 3 is normal, the reception side compares the fixed-cycle serial number L + 3 and L stored in the memory as the received fixed-cycle serial number when receiving this data 14, and is discontinuous. This is detected and the lack of the fixed cycle sequence numbers L + 1 and L + 2 is recognized, and a retransmission request for the data 12 and 13 corresponding to the fixed cycle sequence numbers L + 1 and L + 2 is made to the transmission side. That is, instead of making a retransmission request every time data loss is determined, a retransmission request is executed collectively for a plurality of missing data, so the number of communications is reduced accordingly.

  When the retransmission request 15 is transmitted on the receiving side, the retransmission request is executed with a predetermined delay time after the determination process in order to ensure communication stability after the communication abnormality recovery. In addition, since this retransmission request is not executed in vain, for example, when the data is transmitted due to a large transmission delay or when the periodic data is relatively less important depending on the type, In some cases, the information of the fixed period data may be acceptable. On the other hand, information failure is mostly caused when a communication line is disabled. Therefore, even if a retransmission request is made in such a case, the request itself may not be achieved. Therefore, the apparatus has a function that takes such points into consideration.

  FIG. 5 shows details of the non-reach management of the fixed period information between the devices and the retransmission processing of the first embodiment. The lower level device 2 transmits data to the higher level device 5 via the upstream information transmission device 3, and the higher level device 5 transmits data to the lower level device 2 via the downstream information transmission device 4. The non-arrival detection of the fixed cycle data is T1 + T2, and the host device 5 recognizes the return of the transmission path by using the fixed cycle data 41, but the fixed cycle data (# 2) and (# 3) are delayed by a fixed time in order to ensure communication stability. ) Retransmission request 42 is transmitted to the lower apparatus 2 via the downlink information transmitting apparatus 4. On the other hand, the lower order apparatus 2 retransmits the retransmitted periodic data (# 2) 43 to the upper apparatus 5 via the uplink information transmitting apparatus 3 regardless of the fixed period interval. The host device 5 that has received the retransmission data 43 transmits an arrival confirmation signal ACK 44, and thereafter repeats the retransmission data 45 and ACK 46 to complete a series of retransmission processing. If it is lost in the retransmission process, the retransmission request is not made again.

  FIG. 3 shows event data retransmission processing according to the second embodiment of the present invention. Since event data has an indefinite period for receiving information, it is impossible to detect non-reaching by time as in the first embodiment. Therefore, as shown in FIG. 3, the transmission side has a time management function of T3 for transmission management of event data. In other words, event sequence number notification data that does not include body data only for the purpose of event sequence number notification is transmitted. In FIG. 3, event data 21 is generated and an event sequence number N is added and transmitted to the receiving side. The receiving side receives the event data 21 to which the event sequence number N is added, stores the received event sequence number N, and then waits for the next received data. When 22 occurs after the event data 21, the transmitting side adds the event sequence number N + 1 to the data 22 and transmits it, but is not delivered to the receiving side due to data loss. On the transmission side, if no event data is transmitted after a certain time T3 has elapsed, event sequence number notification data 23 to which the event sequence number N + 2 is added is transmitted. On the receiving side, when the event sequence number notification data 23 is received as in the first embodiment, the received event sequence number N is compared with N + 2 received this time, and it is detected that the event sequence number N + 1 is discontinuous. Recognizing the loss, N + 1 retransmission requests 24 are transmitted to the transmission side. Of course, the reception side sequentially checks the serial number even when receiving normal event data.

  FIG. 4 shows event data retransmission processing using periodic data according to the third embodiment of the present invention. The feature here is that the event serial number of the second embodiment is not notified on the transmission side, and the transmitted event sequence number is added to the fixed cycle data in addition to the fixed cycle sequence number. As a result, the amount of transmitted packets can be reduced compared to the second embodiment. In FIG. 4, fixed-cycle serial numbers L, L + 1, and L + 2 are added to the fixed-cycle data 31, 32, and 33 by the transmission side, respectively, but other fixed-cycle data includes events that occurred immediately before the fixed-cycle data. A serial number is added. That is, in addition to the L periodic cycle serial number, N-1 transmitted event sequence numbers are added to the periodic cycle data 31 and transmitted to the receiving side, and the received periodic cycle number L is stored in the memory on the receiving side. .

  The next fixed cycle data 32 is transmitted with the fixed cycle sequence number L + 1 added at the fixed cycle interval T1, but the event sequence numbers N and N + 1 are generated during the fixed cycle interval T1, and the N + 1 event data is missing. Suppose that Since the event data 34 of the event sequence number N has been normally received, the received event sequence number is saved by rewriting the previous event sequence number N-1 stored in the memory with N, but the event data 35 of the sequence number N + 1. Is not saved due to omission.

  As T1 elapses, the event sequence number N + 1 is added to the fixed cycle data 32 to which the fixed cycle sequence number L + 1 is added as the transmitted event sequence number generated immediately before. When this is received at the receiving side, the fixed cycle data 32 of the fixed cycle sequence number L + 1 is stored as it is, but the event sequence number is N + 1 this time, whereas the stored event sequence number is N and the comparison result is Disagreement. Therefore, the receiving side determines that the event data of the serial number N + 1 is missing, issues a retransmission request 36 of the serial number N + 1 to the transmitting side, and the transmitting side retransmits the event data 37 of the missing serial number N + 1.

  FIG. 6 is a detailed diagram of specific retransmission processing of event information due to missing serial numbers in the higher-level device according to the third embodiment. When a transmission request 51 for event # 1 occurs in the lower apparatus 2, a line connection request 53 is transmitted to the upstream information transmission apparatus 3. After confirming the response 54 from the apparatus 3, the event data 55 of # 1 is transmitted to the upper apparatus 5 via the uplink information transmitting apparatus 3. At this time, it is assumed that an abnormality has occurred in the transmission path between the upstream information transmission device 3 and the higher-level device 5, and the arrival confirmation signal ACK 56 of the event data 55 to be returned from the higher-level device 5 has not reached the lower-level device 2. The lower device 2 transmits the second event data 57 corresponding to the 55 event data # 1 via the uplink information transmission device 3 when a predetermined time T4 elapses and a time-out occurs. Subsequently, after repeating N times determined in the same manner and transmitting the Nth event data 59, a line disconnection request 61 is transmitted to the uplink information transmitting apparatus 3 as a retry over, and the response 62 is confirmed. Even if a transmission request 52 for event # 2 occurs in this state, transmission is not performed until there is a retransmission request from the higher-level device 5.

  At time Tn, as described in FIG. 4, as described with reference to FIG. 4, when the higher order apparatus 5 determines that a loss is detected by an event sequence number in the periodic data, the retransmission request 63 is transmitted from the higher order apparatus 5 via the downlink information transmitting apparatus 4. Sent to. The lower apparatus 2 transmits a line connection request 64 to the uplink information transmitting apparatus 3, confirms the response 65, and retransmits the retransmission 66 of the event data # 1 to the upper apparatus 5 via the uplink information transmitting apparatus 3. Upon receiving the retransmission data 66, the upper apparatus 5 transmits an arrival confirmation signal ACK 67 to the lower apparatus 2 via the downlink information transmitting apparatus 4, and the lower apparatus 2 transmits a retransmission 68 of the event data # 2 to the upstream information. It retransmits to the host device 5 via the transmitter 3. Similarly, the upper device 5 transmits the arrival confirmation signal ACK 69 to the lower device 2 via the downlink information transmitting device 4, and the lower device 2 that has completed the transmission of the retransmission data sends the line disconnection 70 to the upstream information transmitting device 3. Transmitting and confirming the response 71 completes a series of retransmission processes. Also, in the case of the retransmission process according to the second embodiment shown in FIG. 3, the process after the retransmission determination 63 in FIG.

DESCRIPTION OF SYMBOLS 1 ... Network 2 ... Low-order apparatus 3 ... Uplink information transmission apparatus 4 ... Downlink information transmission apparatus 5 ... High-order apparatus 11-14 ... Fixed period data 15 ... Retransmission request of fixed period serial number L + 1, L + 2 T1 ... Fixed period interval T2 ... Sufficient Delay time 21-22 ... Event data 23 ... Event sequence number notification 24 ... Event sequence number N + 1 retransmission request T3 ... Interval until event sequence number notification 31-33 ... Periodic data 34-35 ... Event data 36 ... Event sequence number N + 1 retransmission request 37 ... Retransmission event data with event sequence number N + 1 T4 ... Event data arrival confirmation timeout 81-83 ... Fixed cycle data 84 ... Fixed cycle data retransmission request 91-94 ... Event data 95 ... (Serial number N + 1) to (Sequential number M-1) ) Event data resend request

Claims (1)

The periodic transmission data transmitted from the data transmission device via the network at a constant cycle and the event data transmitted when the event occurs are transmitted to the data reception device. In a network transmission system that performs a retransmission request for missing data,
Means for adding a periodic sequence number that is updated by +1 for each transmission of the periodic data to the data transmission device;
And means for adding each event serial number is updated by +1 every transmission of the event data,
Means for transmitting each fixed cycle data by adding a transmitted event sequence number generated immediately before transmission of the fixed cycle data;
When the arrival confirmation signal of the transmitted event data is not returned within the determined time from the data receiving device, the event data is retransmitted, and a means for disconnecting the line as a retry over after a predetermined number of retransmissions is provided,
Means for returning an event data arrival confirmation signal to the data transmitter;
Each time event data is received, the event sequence number received last time is compared with the event sequence number received this time, and when the event sequence number is discontinuous, it is determined that event data is missing and Provide a means for requesting retransmission,
The data transmission apparatus is configured to retransmit the missing data when a retransmission request is received from the data reception apparatus.

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