JP4535990B2 - Data transmission path construction apparatus and data transmission path construction method - Google Patents

Description

  The present invention relates to a data transmission path construction apparatus and data for constructing a transmission path with improved data transmission reliability in a system in which a plurality of terminals autonomously constructs a transmission path of a wireless network, such as a wireless ad hoc network. The present invention relates to a transmission path construction method.

  2. Description of the Related Art In recent years, wireless ad-hoc networks, in which wireless equipment is attached to a mobile terminal as represented by a wireless LAN and a network is constructed and communicated with each other, are attracting attention. The ad hoc of the wireless ad hoc network means “temporary”, and the network is autonomously constructed and communicated for each communication. There are no servers or the like for managing the terminals. In such a network, it is necessary to construct a network route that enhances the reliability of data transmission, and various methods are being studied.

  A working group of mobile ad hoc networks (MANET: Mobile Ad-Hoc Network) of IETF (Internet Engineering Task Force) discusses a routing protocol that realizes a network autonomously configured by wireless terminals. AODV (Ad- Systems such as Hoc On Demand Distance Vector and DSR (Dynamic Source Routing) have been standardized.

  In addition to these, various methods have been proposed. For example, in Patent Literature 1, a QoS route request is transmitted in order to discover traffic routing based on a quality of service (QoS) parameter, and each node makes a traffic admission control decision. Based on the calculated QoS tag value and the QoS parameter of the QoS route request, each node determines whether to permit traffic according to the QoS route request. The QoS parameters include available bandwidth, error rate, End to End delay, hop count, expected path durability, priority, and the like.

In Patent Document 2, a weighting value is set as a reference value for selection when communication is performed using these communication paths for each communication path connected to another terminal to which a wireless terminal is adjacent. There has also been proposed a method of selecting some of the communication paths connected to the terminal with reference to the weighting value when it arrives.
Further, Patent Document 3 proposes a method for selecting a path based on communication capability information registered in each path connection request message.

JP 2005-524315 A JP 2003-152786 A JP 2004-48478 A

For example, in the AODV method, which is an ad hoc network protocol standardized by IETF MANET, a route construction request message is transmitted to the network, and a response message is received, so that a route table including nodes located in the middle is also obtained. Although the route construction request message is a short message with a fixed length, the route construction request message is accidentally transmitted even on a route with poor circuit quality. Therefore, there is a problem in that data transmitted along a path constructed based on the result may not be able to be transmitted due to an error due to deterioration of channel quality.
Also, in the proposed methods disclosed in each patent document, since the relationship between QoS parameters, weight values, and communication capability information with data that is actually desired to be transmitted is not clear, it is not linked to high reliability of data transmission.

  The present invention has been made to solve the above-described problems. The packet length of the route construction request message is changed based on the length of data to be transmitted. A data transmission path in which a data transmission path (route table) is constructed by sending / receiving a route construction request response message as a reply, and further improving the reliability of data transmission by taking account of the line status between terminals A construction apparatus and a transmission path construction method are provided.

  A data transmission path construction apparatus according to the present invention includes a transmission data size detection circuit that detects the size of data to be transmitted that is received from an external terminal or created by the terminal itself, and a path construction that is transmitted to the network for transmission path construction. Basic control data generating means for generating basic control data including a request message, data size of the route construction request message generated by the basic control data generating means, and data to be transmitted detected by the transmission data size detecting circuit A control data change circuit that compares the sizes and, if the data size to be transmitted is larger than the data size of the route construction request message, changes the data size of the route construction request message to the data size to be transmitted or the maximum packet length And the route structure whose size has been changed by the control data changing circuit. A transmission circuit that transmits a request message to the network, a reception circuit that receives data from the network, and a control data determination circuit that creates route information from a route construction request response message of data received by the reception circuit. It is provided.

  Further, the data transmission path construction method of the present invention compares the size of data to be transmitted received from an external terminal or created by the own terminal with the data size of a route construction request message transmitted to the network for construction of the transmission path. If the data size to be transmitted is larger than the data size of the route construction request message, the data size of the route construction request message is changed to the data size to be transmitted or the maximum packet length and transmitted to the network. The route information is created from the route construction request response message of the data received from the network.

  In addition to the above, a transmission path is constructed based on comprehensively determined information including the received power level between terminals, the S / N of received signals, and the error rate for each line, and transmission and reception of actual data. Is to do.

  The present invention compares the size of data to be actually transmitted with the data size of the route construction request message, and if the data size to be transmitted is larger than the data size of the route construction request message, the data of the route construction request message Since the size is changed to the data size to be sent or the maximum packet length and sent, and the transmission route is built using the route construction request response message that is the reply, the data size of the route construction request message should actually be sent Since the relationship with the data size is clear and the reliability of the transmission path is known by receiving the route construction request response message that is the return signal, there is an effect of improving the reliability of data transmission.

  Furthermore, including information on the response message based on the packet length of the route construction request message under the same conditions as the data to be transmitted, and information on the received power level between terminals, the S / N of the received signal, and the error rate for each line, Since the transmission path can be constructed based on the determined information, there is an effect of further improving the reliability of data transmission.

Embodiment 1
FIG. 1 is a diagram showing an example of a wireless network constructed by applying the present invention, and this network is configured with 15 wireless terminals 1 (A to S) existing in a relatively narrow area. It is a metwork. Each of the wireless terminals 1A to 1S has a terminal address unique to the terminal, and a straight line connecting the terminals 1 indicates a transmission path capable of communication between the terminals. In FIG. 1, when data is transmitted from the terminal 1S to the terminal 1D, a transmission path of terminal 1S-terminal 1C-terminal 1E-terminal 1F-terminal 1J-terminal 1D is constructed and data is transmitted. Show.

  FIG. 2 is a block diagram showing the data transmission path construction apparatus according to Embodiment 1 of the present invention, which is provided in each terminal 1 shown in FIG. In the data transmission path construction apparatus of FIG. 2, the data generation unit 2 stores data such as documents, diagrams, and images to be transmitted created by the terminal itself. The data transmission queue 3 is a memory for temporarily storing data to be transmitted such as data from the data generation unit 2 or data received from an external terminal described later. The transmission data size detection circuit 4 detects the data size of data to be transmitted accumulated in the data transmission queue 3 and outputs size information to the control data change circuit 6. The basic control data generation circuit 5 generates basic control data including a route construction request message to be transmitted to the network in order to construct a transmission path. The control data change circuit 6 changes the data size of the basic control data by a known PN pattern based on the size information from the data size detection circuit 4 and the change control information from the control data determination circuit 11 described later. The transmission data control circuit 7 selects basic control data from the control data change circuit 6 before determining the transmission path of the network, and selects data to be transmitted from the data transmission queue 3 after determining the transmission path. 8 outputs data. The transmission circuit 8 transmits the data selected by the transmission data control circuit 7 to the network.

  The receiving circuit 9 receives data from the network, and has a circuit for measuring the received power level of the control data and a circuit for measuring S / N among the received signals. Output S / N information of control data. The reception signal determination circuit 10 determines the content of the signal received by the reception circuit 9, and outputs it to the control data determination circuit 11 when the reception signal is control data, and enters the reception data transmission queue 12 when the reception signal is reception data. The signal is distributed so that it is output. The control data determination circuit 11 has an error rate measurement circuit that itself measures the control data from the reception signal determination circuit 10, and the error rate information measured by this and the received power level information of the control data received by the reception circuit 9 Further, the route information is created and the change control information is output by comprehensively judging from the S / N information of the control data. The error rate can be measured by calculating an erroneous data amount / total data amount from a known PN pattern in the control data. The reception data transmission queue 12 is a memory for temporarily storing data for relaying and transmitting reception data from other terminals received by the reception circuit 9. The route table 13 describes the transmission route to the transmission destination terminal constructed by the control data determination circuit 11, and instructs the transmission circuit 8 on the basis of the information described in the route table 13 after the route is determined, and transmits the data. Data to be transmitted stored in the queue 3 is transmitted from the transmission circuit 8 to the destination terminal via the network. The data processing circuit 14 processes the received data from the external terminal stored in the received data transmission queue 12 and outputs the signal to the data transmission queue 3.

  3 shows the types of basic control data generated by the basic control data generation circuit 5, FIG. 3 (a) shows a route construction request message, FIG. 3 (b) shows a route construction request response message, and FIG. 3 (c). Indicates a route error message. These message types are distinguished by the data entered in the type field of the data format. The route construction request message is a message sent to the network when it is desired to construct the route of the transmission path, the route construction request response message is a message returned when the route construction request message is received, and the route error message is a link failure. In this case, the message is returned to an adjacent node (terminal) that may be affected.

FIG. 3 (a) shows the data format of a route construction request message of one packet. Assuming that the data size is assumed to be Ethernet (registered trademark), the minimum is 24 bytes / packet and the maximum is 1500 bytes / packet, which will increase further. There is no. That is, the data from the type area to the source sequence area is 24 bytes and the data area is 0 to 1476 bytes. The data size of the route construction request message is changed by inserting a PN pattern in the data area. The pattern length of the route construction request message is changed depending on the size of the PN pattern to be inserted, and the maximum packet length is 1500 bytes. Here, the PN pattern is a pseudo-random pattern.
The address information of the terminal (terminal 1D in the example of FIG. 1) that finally sent the data is included in the destination address area of the data format of the route construction request message.

FIG. 3B shows the data format of a route construction request response message of one packet, and the data in the data area includes information on transmission paths between terminals constructed by the data transmission path construction device of each terminal. ing.
FIG. 3C shows the data format of a one-packet route error message, which includes address information of a terminal that may be affected when a link failure occurs in the non-delivery destination address area. .

Next, an operation for constructing a transmission path by the data transmission path construction apparatus shown in FIG. 2 will be described with reference to FIGS. Here, an operation when data is transmitted from the terminal 1S to the terminal 1D in the network of FIG. 1 will be described. Here, the terminal having the data transmission path construction device shown in FIG. 2 indicates the terminal 1S.
First, in the terminal 1 </ b> S, data to be transmitted from the data generation unit 2 or the data processing unit 14 enters the data transmission queue 3. In STEP 1 of FIG. 4, the transmission data size detection circuit 4 detects the size of data to be transmitted stored in the data transmission queue 3.
In STEP 2, the control data change circuit 6 compares the data size of the route construction request message generated by the basic control data generation circuit 5 with the data size of the data to be transmitted detected by the transmission data size detection circuit 4, and transmits the data. If the power data size is larger than the data size of the route construction request message, the data size of the route construction request message is increased to the data size to be transmitted or the maximum packet length. The content of the data to be increased is based on a known PN pattern.
Here, when the data size of the route construction request message is to be transmitted, the data size to be transmitted is smaller than the maximum packet length. In addition, when the data size of the route construction request message is set to the maximum packet length, the data size to be transmitted is larger than the maximum packet length. If the data size to be transmitted is smaller than the data size of the route construction request message, the data size of the route construction request message is left as it is.

  In STEP 3, the route construction request message whose data size has been changed is transmitted from the transmission circuit 8 to the adjacent terminals 1E and 1C constituting the network via the transmission data control circuit 7. Each terminal in the network transmits a route construction request message by broadcast. Upon receiving the route construction request message, the terminal 1E returns a route construction request response message to the terminal 1S. Similarly, when receiving the route construction request message, the terminal 1C returns a route construction request response message to the terminal 1S.

  In STEP 4, when the reception circuit 9 of the terminal 1S receives the route construction request response message from the terminal 1E, the power level measurement circuit and the S / N measurement circuit included in the reception circuit 9 control the received signal from the terminal 1E. The received power level of the data (route construction request response message) and the S / N of the control data of the received signal are measured. The measurement result is transmitted to the control data determination circuit 11 as received power level information of the received signal and S / N information of the received signal. The route construction request response message received by the receiving circuit 9 is also transmitted to the received signal determination circuit 10. In the reception signal determination circuit 10, since the received route construction request response message is control data, it is transmitted to the control data determination circuit 11. The control data determination circuit 11 measures the line error rate from the transmitted control data using a known PN pattern.

In STEP5, as in STEP4, when the receiving circuit 9 of the terminal 1S receives the route construction request response message from the terminal 1C, the power level measuring circuit and S / N measuring circuit included in the receiving circuit 9 are received from the terminal 1C. The received power level of the received signal control data (route construction request response message) and the S / N of the received signal control data are measured. The measurement result is transmitted to the control data determination circuit 11 as received power level information of the received signal and S / N information of the received signal. The route construction request response message received by the receiving circuit 9 is also transmitted to the received signal determination circuit 10. In the reception signal determination circuit 10, since the received route construction request response message is control data, it is transmitted to the control data determination circuit 11. The control data determination circuit 11 measures the line error rate from the transmitted control data using a known PN pattern.
In STEP 6, the control data determination circuit 11 performs error rate information on the line measured by itself, received power level information of the received signal from the terminal 1E, S / N information of the received signal, and received power of the received signal from the terminal 1C. The transmission path is determined by comprehensively judging level information and S / N information of the received signal.

FIG. 5 shows an example of a method in which the control data determination circuit 11 determines a transmission path by comprehensive determination of line error rate information, reception power level information, and received signal S / N information, and is adjacent to the terminal 1S. A case where data transmission to the terminal 1E is desired is shown.
First, in STEP 11 of FIG. 5, the control data determination circuit 11 of the terminal 1S measures the error rate information and the received power level information of the received signal measured from the received signals of the route construction request response messages from the terminals 1E and 1C. And S / N information of the received signal is obtained.
In STEP 12, the control data determination circuit 11 comprehensively determines the error rate of the line between the terminal 1S and the terminal 1E and between the terminal 1S and the terminal 1C, the received power level from the terminal 1E and the terminal 1C, and the S / N. It is determined which of the route of the terminal 1E and the route of the terminal 1S-terminal 1C has higher data transmission reliability.
In the example of FIG. 5, the route to the terminal 1E has a power level, but the error rate is bad, so it is determined that the data is difficult to reach. The route to the terminal 1C has a low power level but a good error rate. Therefore, it is judged that the data is easy to reach. From these results, in STEP 13, the route is decided to be the route of terminal 1S-terminal 1C.

Next, in STEP 14, the control data determination circuit 11 of the terminal 1C, which has been routed to the terminal 1S, receives the error rate information measured from the received signals of the route construction request response messages from the terminals 1E and 1S, and Received power level information of the received signal and S / N information of the received signal are obtained.
In STEP 15, the control data determination circuit 1 of the terminal 1C comprehensively determines the line error rate between the terminal 1C and the terminal 1E and between the terminal 1C and the terminal 1S, the received power level from the terminal 1E and the terminal 1S, and the S / N. It is determined which of the route of terminal 1C-terminal 1E and the route of terminal 1C-terminal 1S is more reliable in data transmission. In the example of FIG. 5, it is determined that the route with the terminal 1E and the route with the terminal 1S have the same conditions for the power level, S / N, and error rate.
In STEP 16, it is determined that the reliability of data transmission is the same for the route of the terminal 1C-terminal 1E and the route of the terminal 1C-terminal 1S. In this case, the route is decided to be the terminal 1C-terminal 1E.

  Next, the terminal 1E whose path is determined obtains error rate information with adjacent terminals, reception power level information of the received signal, and S / N information of the received signal in the same manner as described above, and determines the next path. . Thus, a route to the destination terminal 1D is determined, and a data transmission route is constructed.

Returning to FIG. 4, in STEP 7, the route to the terminal 1 </ b> S is determined as the terminal 1 </ b> C in the comprehensive determination in STEP 6, and the result is recorded in the route table 13. Similarly, the route to the terminal 1C is determined as the terminal 1E, and this information is put in the data area of the route construction request response message from the terminal 1C and returned to the terminal 1S. In this way, the route from the terminal 1S of the transmission source to the terminal 1D of the transmission destination is sequentially determined, and the node (terminal) in which the route from the terminal 1S to the terminal 1D is positioned in the route table 13 of the terminal 1S. Will be recorded.
In STEP 8, when a route from the transmission source terminal to the transmission destination terminal is established, the route table 13 sends a signal to the transmission circuit 8, and based on the transmission route recorded in the route table 13, the data transmission key 3 of the terminal 1S. The accumulated data to be transmitted is transmitted from the transmission circuit 8 to the network. Thus, the data to be transmitted stored in the transmission source terminal 1S is transmitted to the transmission destination terminal 1D.

Further, in the overall determination of STEP 6, when it is determined that the error rate, the reception power level, and the S / N are all bad and the data is difficult to reach, as shown in STEP 9, the control data determination circuit 11 displays the change control information. Create and output to the control data change circuit 6.
On the other hand, if the route construction request response message is not returned after the transmission of the route construction request message in STEP 3, the reception signal judgment circuit 10 detects the time-out and sends the time-out information to the control data judgment circuit 11. Also in this case, as shown in STEP 9, the control data determination circuit 11 creates change control information based on the timeout information and outputs it to the control data change circuit 6.
This change control information is a signal for requesting to reduce the data size of the route construction request message. In response to the change control information, the control data change circuit 5 changes the data size of the route construction request message transmitted last time to obtain a route construction request message having a packet length with a reduced data size. In this way, the route construction request message with the packet length reduced is transmitted from the terminal 1S to the network again. By repeating this operation until the terminal 1S receives the route construction request response message or until any of the error rate, received power level, and S / N is improved, the route can be constructed. At this time, the data size to be actually transmitted is divided and adjusted to a size equal to or smaller than the route construction request message in the state where the route is constructed, and subsequent data transmission / reception is performed.
In short, according to the present invention, if a route construction request message corresponding to data to be transmitted is transmitted and a route construction request response message is received, it is determined that data transmission of a desired data size is possible on the route. On the other hand, if a route construction request response message is not returned, it is determined that there is an error somewhere and transmission could not be performed. Basically, it uses the idea that the reliability of control data information is replaced with the reliability of normal data transmission.

Embodiment 2
FIG. 6 is a block diagram showing the second embodiment of the present invention, in which the reception power level measurement circuit and the received signal S / N measurement circuit are omitted from the reception circuit 9 of the first embodiment of the present invention shown in FIG. The receiving circuit 9a is changed to a simplified circuit that only receives data from the network. In this case, since the control data determination circuit 11a does not need to determine the power level information and S / N information of the received signal, it is changed to the simple type. The control data determination circuit 11a creates path information and outputs change control information from the control data from the received signal determination circuit 10 and its error rate information. That is, in the second embodiment, the control data determination circuit 1 determines based on the timeout information and error rate of the control data received by the receiving circuit, and creates the change control information and the path information. Even in this case, a highly reliable data transmission path can be constructed.

Embodiment 3
FIG. 7 is a block diagram showing the third embodiment of the present invention, which is simplified by omitting the circuit for measuring the error rate of the control data from the control data determining circuit 11a of the second embodiment of the present invention shown in FIG. The control data determination circuit 11b generates route information and outputs change control information only from the control data from the reception signal determination circuit 10 and timeout information. In this case, the control data change circuit 6a is simplified compared to the control data change circuit 6 shown in FIGS. 2 and 6, and the data size of the basic control data is changed according to the change control information and the size information. Even in this case, a highly reliable data transmission path can be constructed.

Embodiment 4
In the first embodiment described above, the case where the reception circuit 9 has both the reception power level measurement circuit and the S / N measurement circuit has been described. However, either the reception power level measurement circuit or the S / N measurement circuit is used. It may be provided with one side. In this case, the control data determination circuit 12 creates change control information and path information based on either the power level information or the S / N information, the error rate information, and the timeout information. Even in this case, a highly reliable data transmission path can be constructed.

The figure which showed an example of the network constructed | assembled by this invention. BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows Embodiment 1 of this invention. Format of basic control data used in the present invention. FIG. 3 is a flowchart showing a route construction operation according to the first embodiment. Schematic which shows an example of the comprehensive determination method for the route | root construction by Embodiment 1. FIG. The block diagram which shows Embodiment 2 of this invention. The block diagram which shows Embodiment 3 of this invention.

Explanation of symbols

1: terminal 2: data generation unit 3: data transmission queue 4: transmission data size detection circuit 5: basic control data generation circuit 6: control data change circuit 7: transmission data control circuit 8: transmission circuit 9: reception circuit 10: reception Signal determination circuit 11: Control data determination circuit 12: Received data transmission queue 13: Path table 14: Data processing unit

Claims (8)

In a wireless terminal used in a network in which a plurality of terminals autonomously construct a transmission path of a wireless network,
A transmission data size detection circuit that detects the size of data to be transmitted received from an external terminal or created by the own terminal;
Basic control data generating means for generating basic control data including a route construction request message to be transmitted to the network for transmission path construction;
The data size of the route construction request message generated by the basic control data generation means is compared with the size of the data to be transmitted detected by the transmission data size detection circuit, and the data size to be transmitted is the route construction request message. Control data change circuit for changing the data size of the route construction request message to the data size to be transmitted or the maximum packet length,
A transmission circuit for transmitting a route construction request message resized by the control data change circuit to the network;
A receiving circuit for receiving data from the network;
A data transmission path construction apparatus comprising: a control data determination circuit that creates path information from a data route construction request response message received by the receiving circuit.   The control data determination circuit creates change control information based on the timeout information of the control data received by the receiving circuit, and the control data change circuit reduces the data size of the route construction request message by the change control information. The data transmission path construction apparatus according to claim 1.   The control data determination circuit has a circuit that measures an error rate from the control data received by the receiving circuit, creates change control information based on the measurement result of the error rate, and the control data change circuit includes the change control information. 3. The data transmission path construction apparatus according to claim 1, wherein the data size of the route construction request message is reduced by the method.   The reception circuit has a circuit for measuring the reception level of the received control data, the control data determination circuit creates change control information based on the measurement result of the reception level, and the control data change circuit has the change control The data transmission path construction device according to any one of claims 1 to 3, wherein the data size of the route construction request message is reduced by information.   The reception circuit has a circuit for measuring the S / N of the received control data, the control data determination circuit creates change control information based on the measurement result of the S / N, and the control data change circuit The data transmission path construction device according to any one of claims 1 to 4, wherein the data size of the route construction request message is reduced by the change control information. In a wireless terminal used in a network in which a plurality of terminals autonomously construct a transmission path of a wireless network,
A data transmission queue for temporarily storing data to be transmitted received from an external terminal or created by the own terminal;
A transmission data size detection circuit for detecting the data size of the data to be transmitted;
Basic control data generating means for generating basic control data including a route construction request message to be transmitted to the network for transmission path construction;
The data size of the route construction request message generated by the basic control data generation means is compared with the size of the data to be transmitted detected by the transmission data size detection circuit, and the data size to be transmitted is the route construction request message. Control data change circuit for changing the data size of the route construction request message to the data size to be transmitted or the maximum packet length,
A transmission data control circuit for selecting one of the data to be transmitted stored in the data transmission queue or the basic control data after the change and transmitting the data to the network line;
A transmission circuit for transmitting the data selected by the transmission data control circuit to the network;
A receiving circuit for receiving data from the network;
A content of a received signal received by the receiving circuit, a control signal or received data is recognized, a received signal determining circuit for performing distribution; and
A control data determination circuit that creates route information from the route construction request response message of the control data distributed by the received signal judgment circuit and outputs change control information that changes the data size of the route construction request message;
A route table that describes the route constructed by the control data determination circuit;
A data transmission path construction apparatus comprising: a reception data transmission queue for temporarily storing data for transmitting reception data from the reception signal determination circuit to the outside.   The control data determination circuit creates change control information based on one or more measurement results of the received level, S / N, and error rate of the received control data, and the control data change circuit includes the change control information 7. The data transmission path construction device according to claim 1, wherein the data size of the route construction request message is reduced by the method. In a data transmission path construction method in which a plurality of terminals autonomously construct a wireless network transmission path,
Compare the size of the data to be transmitted received from the external terminal or created by the own terminal with the data size of the route construction request message sent to the network for constructing the transmission path, and the data size to be transmitted is If it is larger than the data size of the route construction request message, change the data size of the route construction request message to the data size to be transmitted or the maximum packet length, and send it to the network, and construct the route of the data received from the network A data transmission path construction method in which path information is created from a request response message.

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