JP5849475B2 - Communication terminal and failure detection method in communication system - Google Patents

Description

  The present invention relates to a communication terminal and a failure detection method in a communication system that can shorten the time until failure detection when a failure occurs in a communication system.

  In an ad hoc network where each terminal performs routing autonomously (routing without control by other devices), a failure occurs if the terminal does not store routing information indicating the data transfer path It is difficult to identify the cause of the failure because the routing information cannot be recognized.

  In ad hoc networks, information such as the transmission error rate and congestion level included in the routing information is used to estimate the transmission band bottleneck on the transmission path and to allocate efficient transmission band to terminals and relay nodes. There is a network control device that performs dynamically (see, for example, Patent Document 1).

Re-specialized WO2009 / 28185

  Data transmitted and received in the ad hoc network is transferred via the terminal. When data sent normally from the terminal itself is discarded by the transfer destination terminal, if it cannot be recognized that the transfer source terminal has been discarded, it is discarded at a higher layer such as an application provided in the server or terminal. It is necessary to perform detection and retransmission request.

  FIG. 8 is a block diagram illustrating an example of the configuration of the communication system. The collection server 700 illustrated in FIG. 8 receives data periodically transmitted from the terminals 501 to 512 via the gateway (GW) 600. When the collection server detects that data has not been received, the collection server makes a retransmission request to the corresponding terminal. For example, as shown in FIG. 8, when the data transmitted from the terminal 507, the terminal 508, the terminal 509, the terminal 510, and the terminal 511 is not received, the collection server It is necessary to make a resend request. “Req” illustrated in FIG. 8 represents a retransmission request transmitted from the collection server 700.

  In the communication system shown in FIG. 8, data discard detection and retransmission request are performed in an upper layer or the like, and there is a problem that it takes time to detect discard and processing for retransmission request.

  Therefore, an object of the present invention is to provide a communication terminal and a failure detection method in a communication system that can detect data discard due to a failure in the communication system in a short time and shorten the time until data retransmission. .

A communication terminal according to the present invention is a communication terminal in a communication system including a plurality of communication terminals that autonomously transfer data to another adjacent terminal, and a transmission unit that transmits data to the other adjacent terminal; Receiving means for outputting data received from other terminals as transmission data to the transmission means, and when the transmission means does not receive a reception response even after a lapse of a certain time after transmitting the transmission data, It is determined that the transmission data is discarded, and a transmission history including a transmission number that can identify the transmission data, a reception number that can identify the reception data included in the transmission data, and a reception terminal number that can identify the transmission source of the reception data If it is determined that the transmission data has been discarded, a discard signal indicating that the reception data included in the transmission data has been discarded is transmitted based on the transmission history. And an information management means for transmitting to, the information management unit, the transmitting means transmits the data, even after the total time of the network uplink maximum delay time and network downlink maximum delay time is not received discard signal In this case, it is determined that the data transmission is successful, and the information management unit deletes the transmission history corresponding to the transmission data when the transmission unit successfully transmits the transmission data.

A failure detection method in a communication system according to the present invention is a failure detection method in a communication system that includes a plurality of communication terminals that autonomously transfer data to other adjacent terminals. The transmission data is generated by combining the received data, the transmission number that can identify the transmission data, the reception number that can identify the reception data included in the transmission data, and the reception terminal number that can identify the transmission source of the reception data If the transmission history is stored and the reception response is not obtained even after a lapse of a certain time after transmitting the transmission data, it is determined that the transmission data is discarded, and the transmission data is discarded , based on the transmission history, a discard signal indicating that the received data is discarded and sent to the transmission source of the received data, from the transmission of the data included in the transmitted data, networks If even after the total time of the click uplink maximum delay time and network downlink maximum delay time is not received discard signal, determines that the data transmission is successful, the transmission data upon successful transmission of the transmission data The corresponding transmission history is deleted.

  According to the present invention, in a communication system in which a communication terminal autonomously performs routing control, data discard due to a failure can be detected in a short time, and the time until data retransmission can be shortened.

It is a block diagram which shows the structure of 1st Embodiment of the communication terminal by this invention. It is a block diagram which shows an example of a structure of the communication system containing the communication terminal by this invention. It is explanatory drawing which shows an example of the transmission history table which a passage information management part memorize | stores. It is explanatory drawing which shows a mode when a failure generate | occur | produces in the communication system shown in FIG. It is explanatory drawing which shows a mode that an NG signal is output from each terminal in the communication system shown in FIG. It is explanatory drawing which shows a mode that a path | route is changed in the communication system shown in FIG. 2, and resending of data is performed. It is a block diagram which shows the principal part of the communication terminal by this invention It is a block diagram which shows an example of a structure of a communication system.

Embodiment 1. FIG.
A first embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a first embodiment of a communication terminal according to the present invention.

  As shown in FIG. 1, the communication terminal according to the present invention includes an uplink terminal reception processing unit 110, an information buffer 120, an uplink terminal transmission processing unit 130, a passage information management unit 140, a downlink terminal reception processing unit 150, A downlink terminal transmission processing unit 160 and a terminal information management unit 170 are provided.

  The uplink terminal reception processing unit 110 receives data from an adjacent downstream terminal.

  Uplink terminal reception processing section 110 outputs data received from an adjacent downstream terminal to information buffer 120 as transmission data. When receiving data from a plurality of adjacent downstream terminals, the uplink terminal reception processing unit 110 combines the data and outputs the combined data to the information buffer 120 as transmission data. When the in-terminal data generated in the communication terminal is stored in the terminal information management unit 170, the uplink terminal reception processing unit 110 acquires the in-terminal data from the terminal information management unit 170, and acquires the acquired in-terminal data Transmission data is generated by combining the data and the data received from the downstream terminal.

  Also, the uplink terminal reception processing unit 110 outputs received information identification to the passage information management unit 140. The reception information identification includes a transmission number, a reception terminal number, and a reception number. The transmission number is a number for identifying data (hereinafter referred to as a data identification number) and is a data identification number of data transmitted from the uplink terminal transmission processing unit 130. The reception number is a data identification number of data received from a terminal adjacent on the downstream side. The receiving terminal number is a number for identifying a terminal (hereinafter referred to as a terminal number), and is a terminal number of a transmission source of received data.

  The information buffer 120 stores data input from the uplink terminal reception processing unit 110.

  The uplink terminal transmission processing unit 130 reads out the data stored in the information buffer 120, adds a data identification number to the read data, and transmits the data. Further, the data stored in the information buffer 120 is stored until the uplink terminal transmission processing unit 130 completes transmission. When the uplink terminal transmission processing unit 130 determines that the data transmission has failed and the data has been discarded, the uplink terminal transmission processing unit 130 passes the transmission number of the data that has failed to be transmitted and information indicating whether the data has been discarded or not. The data is output to the management unit 140.

  The passage information management unit 140 generates a transmission history based on the received information identification and stores it in the transmission history table. The transmission history includes a sending number, a receiving terminal number, and a receiving number.

  The downlink terminal reception processing unit 150 receives data from the adjacent upstream terminal. When receiving the NG signal including the data identification number of the discarded data, the downlink terminal reception processing unit 150 outputs the data identification number acquired from the NG signal to the passage information management unit 140.

  The downlink terminal transmission processing unit 160 transmits data to the adjacent downstream terminal. Further, the downlink terminal transmission processing unit 160 inputs a discard notification from the passage information management unit 140. The discard notification includes the data identification number of the discarded data and the terminal number of the transmission source of the discarded data.

  When receiving the discard notification, the downlink terminal transmission processing unit 160 transmits an NG signal including the data identification number of the discarded data to the terminal that has transmitted the discarded data. Further, when the data in the terminal is included in the discarded data, the data identification number of the data in the terminal is output to the terminal information management unit 170.

  The terminal information management unit 170 stores and deletes in-terminal data.

  Next, the operation of this embodiment will be described.

  FIG. 2 is a block diagram showing an example of a configuration of a communication system including a communication terminal according to the present invention. FIG. 3 is an explanatory diagram illustrating an example of a transmission history table stored in the passage information management unit.

  The communication system shown in FIG. 2 includes a collection server 400 that collects data from each terminal, a GW 300, and terminals 201 to 212. Terminals 201 to 212 are communication terminals having the configuration shown in FIG. The terminals 201 to 212 and the GW 300 form an ad hoc network. The collection server 400 is connected to the terminals 201 to 212 via the GW 300 so as to be communicable.

  When the terminals 201 to 212 hold the in-terminal data to be transmitted, the terminals 201 to 212 transmit the data to the adjacent terminals on the collection server 400 side (upstream side). In addition, when receiving data from an adjacent downstream terminal, the terminals 201 to 212 transfer the received data to the adjacent upstream terminal.

  Here, the terminal numbers of the terminal 205, the terminal 207, the terminal 208, the terminal 209, the terminal 210, and the terminal 211 are A, B, C, D, E, and F, respectively. Further, an example is given in which each terminal transfers data J, data K, data L, data M, data O, and data P to an adjacent upstream terminal. “Data X” refers to data whose data identification number is X. In addition, a case where the transmission history corresponding to the data J and the data K has the contents shown in FIGS. 3A and 3B is taken as an example.

  FIG. 4 is an explanatory diagram showing a situation when a failure occurs in the communication system shown in FIG. FIG. 4 shows a state in which the terminal 205 has failed to transmit data J.

  FIG. 5 is an explanatory diagram showing a state in which an NG signal is output from each terminal in the communication system shown in FIG.

  The uplink terminal transmission processing unit 130 of the terminal 205 determines that the data J has been discarded when the transmission of the data J fails, such as when a reception response is not obtained even after a predetermined time has passed from the destination terminal. To do. Then, the information indicating that the data J has been discarded and the transmission number are output to the passage information management unit 140. If the data transmission is successful, only the transmission number is output to the passage information management unit 140.

  When the information indicating that the data J has been discarded is input from the upstream terminal transmission processing unit 130 together with the transmission number, the passage information management unit 140 of the terminal 205 is based on the transmission history with the transmission number J. Then, the data included in the data J is determined. As shown in FIG. 3A, data J includes data K received from terminal 207 whose terminal number is B, data L received from terminal 208 whose terminal number is C, and terminal 209 whose terminal number is D. The data M received from

  Passage information management section 140 of terminal 205 outputs a discard notification indicating that data K, data L and data M included in data J have been discarded to downlink terminal transmission processing section 160.

  When the downlink terminal transmission processing unit 160 inputs the discard notification, the terminal 207, the terminal 208, and the terminal 209 notify the terminal 207, the terminal 208, and the terminal 209 that the data K, the data L, and the data M are discarded, as shown in FIG. An NG signal including the data identification number of the discarded data is transmitted to each terminal. “NG (X)” shown in FIG. 5 represents an NG signal including the data identification number X.

  When receiving the NG signal from the terminal 205, the downlink terminal reception processing unit 150 of the terminal 207 outputs the data identification number K included in the NG signal to the passage information management unit 140. Note that the operation when the terminal 208 and the terminal 209 receive an NG signal from the terminal 205 is the same as that of the terminal 207, and thus the description thereof is omitted.

  When the data identification number K is input from the downlink terminal reception processing unit 150, the passage information management unit 140 of the terminal 207 receives the data included in the discarded data K based on the transmission history with the transmission number K. to decide. As shown in FIG. 3B, the data K includes data O received from the terminal 210 whose terminal number is E, data P received from the terminal 211 whose terminal number is F, and data Q which is intra-terminal data. Including.

  Further, the passage information management unit 140 of the terminal 207 outputs a discard notification indicating that the data O and the data P included in the data K are discarded to the downlink terminal transmission processing unit 160.

  When the discard notification is input, the downlink terminal transmission processing unit 160 of the terminal 207 discards in order to notify the terminal 210 and the terminal 211 that the data O and the data P are discarded, as shown in FIG. An NG signal including the data identification number of the received data is transmitted to each terminal. Also, the downlink terminal transmission processing unit 160 outputs the data identification number of the data Q to the terminal information management unit 170 in order to notify the terminal information management unit 170 that the data Q has been discarded.

  When the data identification number is input, the terminal information management unit 170 of the terminal 207 continues to hold the data Q without deleting it so that the uplink terminal reception processing unit 110 can read the data Q again.

  Note that the passage information management unit 140 and the terminal information management unit 170 of each terminal have a maximum uplink network delay time (time until the data reaches the collection server 400) Tup and a maximum downlink network after data is transmitted from the terminal. Delay time (time until the data from the collection server 400 arrives at the terminal) Even if a time longer than the total time of Tdown elapses, if no information indicating that the data has been discarded is input, data transmission Is determined to be successful. Then, passage information management section 140 deletes the transmission history corresponding to the data from the transmission history table, and terminal information management section 170 deletes the in-terminal data. 4 and 5 show Tup and Tdown for the terminals 210, 211, and 212 that are located farthest from the collection server 400 (most downstream).

  For example, in the case of the terminals 210 to 212 shown in FIGS. 4 and 5, the time tup from when the data is transmitted from the terminals 210 to 212 until the data J is discarded, and the terminals 210 to 212 after the data J is discarded. Since the total time with the time tdown until the NG signal is received becomes shorter than the total time of Tup and Tdown, the transmission history and the data in the terminal held by the terminals 210 to 212 are held without being deleted.

  FIG. 6 is an explanatory diagram showing how data is retransmitted by changing the route in the communication system shown in FIG.

  As illustrated in FIG. 6, when receiving an NG signal, the terminal 210 and the terminal 211 retransmit data O and data P to the terminal 207, respectively. In addition, when the terminal 207, the terminal 208, and the terminal 209 receive the NG signal, the terminal 207 determines that the data transfer via the terminal 205 (see FIG. 4) has failed, and a route that does not pass through the terminal 205, for example, the terminal 204 The data Q, the data R, and the data S are retransmitted through a route passing through. Data R and data S indicate in-terminal data of the terminal 208 and the terminal 209.

  As described above, according to the present embodiment, in an ad hoc network or the like that performs data transfer via another adjacent terminal, each terminal transmits data based on the data identification number and the terminal number. Since the terminal that is the data discarding point, that is, the terminal that failed to transmit data, transmits the NG signal to the adjacent terminal based on the transmission history, the transmission history is managed. Can be shortened, and the time from failure occurrence to data retransmission can be shortened.

  Also, since no transmission history is recorded when transmission is successful, discard information and a discard route can be identified from the transmission history stored in each terminal when a failure occurs. Control information for identifying information and discard routes is not required. In addition, since a large amount of transmission history is not accumulated, it is not necessary to provide a large-capacity storage memory.

  Since the NG signal is transmitted to the downstream terminal from the data discarding point, the collection server does not make a data retransmission request for each terminal as in the communication system shown in FIG. Retransmission can be performed.

  In this embodiment, the case where the transmission history of data transmitted from the downstream terminal to the upstream terminal is managed as the discard information has been described. However, the data is transmitted from the upstream terminal to the downstream terminal. You may make it manage the transmission history about data.

  FIG. 8 is a block diagram showing the main part of a communication terminal according to the present invention. As shown in FIG. 8, the communication terminal is a communication terminal in a communication system including a plurality of communication terminals that autonomously transfers data to other adjacent terminals, and transmits the data to other adjacent terminals. 12 (corresponding to the uplink terminal transmission processing unit 130 shown in FIG. 1) and reception means 11 (uplink terminal reception processing unit 110 shown in FIG. 1) that outputs data received from other adjacent terminals to the transmission means as transmission data. And a transmission history including a transmission number that can identify transmission data, a reception number that can identify reception data included in the transmission data, and a reception terminal number that can identify the transmission source of the reception data, Information management for transmitting a discard signal indicating that the received data included in the transmission data has been discarded to the transmission source of the reception data based on the transmission history when it is determined that the transmission data has been discarded Stage 13 (pass information management unit 140 shown in FIG. 1, a downlink terminal reception processing unit 150, corresponding to downlink terminal transmission processing section 160 and the terminal information management unit 170.) And a.

  The following communication terminals are also disclosed in the above embodiment.

(1) The information management unit 13 receives the data when the discard signal is not received even after the total time of the network uplink maximum delay time and the network downlink maximum delay time elapses after the transmission unit 12 transmits the data. A communication terminal that determines that transmission was successful.

(2) The information management unit 13 is a communication terminal that deletes the transmission history corresponding to the transmission data when the transmission unit 12 succeeds in transmitting the transmission data.

(3) The information management unit 13 determines that the transmission data is discarded when the transmission unit 12 fails to transmit the transmission data or receives a discard signal from the transmission data transmission destination terminal. .

(4) When the information management unit 13 stores the in-terminal data, the receiving unit 11 combines the data received from other adjacent terminals with the in-terminal data to generate transmission data, and the information The management means 13 is a communication terminal that deletes in-terminal data when the transmission means 12 succeeds in transmitting transmission data.

DESCRIPTION OF SYMBOLS 11 Reception means 12 Transmission means 13 Information management means 110 Uplink terminal reception process part 120 Information buffer 130 Uplink terminal transmission process part 140 Passing information management part 150 Downlink terminal reception process part 160 Downlink terminal transmission process part 170 Terminal information management part 201-212 , 501 to 512 Terminal 300, 600 GW
400, 700 Collection server

Claims (4)

A communication terminal in a communication system including a plurality of communication terminals that autonomously transfer data to other adjacent terminals,
A transmission means for transmitting data to other adjacent terminals;
Receiving means for outputting data received from other adjacent terminals to the transmitting means as transmission data;
The transmission means determines that the transmission data is discarded when a reception response is not obtained even after a lapse of a certain time after transmitting the transmission data;
Storing a transmission history including a transmission number that can identify transmission data, a reception number that can identify reception data included in the transmission data, and a reception terminal number that can identify a transmission source of the reception data; An information management means for transmitting a discard signal indicating that the received data included in the transmission data is discarded based on the transmission history to the transmission source of the received data when it is determined that the received data is discarded; Prepared,
The information management means succeeds in data transmission when the discard signal is not received even after the total time of the network uplink maximum delay time and the network downlink maximum delay time elapses after the transmission means transmits the data. Judging
The communication terminal, wherein the information management unit deletes a transmission history corresponding to the transmission data when the transmission unit succeeds in transmitting the transmission data. Information management means, the communication terminal according to claim 1 for determining when receiving a discard signal from the destination terminal of transmission data, and the transmission data is discarded. When the information management means stores the in-terminal data, the receiving means combines the data received from other adjacent terminals and the in-terminal data to generate transmission data,
It said information management means when the transmission means has successfully transmitted the transmission data, communication terminal according to claim 1 or claim 2 Remove the data the terminal. A failure detection method in a communication system including a plurality of communication terminals that autonomously transfer data to other adjacent terminals,
The communication terminal is
Combining data received from other adjacent terminals to generate transmission data,
Storing a transmission history including a transmission number that can identify the transmission data, a reception number that can identify reception data included in the transmission data, and a reception terminal number that can identify a transmission source of the reception data;
When a reception response is not obtained even after a lapse of a certain time after transmitting the transmission data, it is determined that the transmission data is discarded,
When it is determined that the transmission data is discarded, based on the transmission history, a discard signal indicating that the reception data included in the transmission data is discarded is transmitted to the transmission source of the reception data,
If the discard signal is not received after the total time of the network upstream maximum delay time and the network downstream maximum delay time has elapsed since the data was transmitted, it is determined that the data transmission was successful,
A failure detection method comprising: deleting transmission history corresponding to the transmission data when transmission of the transmission data is successful.

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