JP2001196990A - Relay transmission method, relay transmission system and device used for them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relay transmission method that can efficiently realize relay transmission attended with re-transmission control in a half duplex transmission line and to provide a relay transmission system and a device used for them. SOLUTION: A sender side transmitter 30 receiving a polling signal from a receiver side transmitter 20 transmits a data frame with a frame number to a relay transmitter 10. The relay transmitter 10 transmits the normally received data frame to a next stage while storing the frame into a frame buffer 105 for re-transmission. The receiver side transmitter 20 generates a re- transmission request of a data frame unable to be normally received and transmits the request to the relay transmitter 10. When the frame buffer 105 for re-transmission has the data frame whose re-transmission is requested, the relay transmitter 10 eliminates the frame number from the re-transmission request and transfers the resulting request. Then the relay transmitter 10 adds the data frame of the eliminated frame number to data frames that are retransmitted and relays the resulting data frames.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a relay transmission method and a relay transmission system in which a relay transmission device is provided between a transmission device for transmitting data and a transmission device for receiving data to perform relay transmission. TECHNICAL FIELD The present invention relates to a relay transmission method and a relay transmission system for relaying and transmitting data without simultaneously performing transmission and reception.

[0002]

2. Description of the Related Art Conventionally, as a technique for improving the throughput when transferring packet data from a transmission transmission apparatus to a reception transmission apparatus via a relay transmission apparatus, for example, a technique described in Japanese Patent Application Laid-Open No. 9-181772 is known. Are known.
Hereinafter, this conventional example will be described.

FIG. 15 is a diagram showing a configuration of a data transmission system in the above-mentioned conventional example. In FIG.
The data transmission system includes a data terminal 1521 that generates data, and an outgoing data transmission device 15 that converts data received from the data terminal 1521 into packet data and transmits the packet data.
11 and the packet data transmitted from the outgoing data transmission device 1511 by using a mobile satellite link 1503 by a low-orbit satellite.
Relay data transmission device 15 that receives and relays via
12 and a relay data transmission device 1513 for receiving and relaying the packet data transmitted from the relay data transmission device 1512 via the satellite link 1504 by the geostationary satellite.
A destination data transmission device 1514 for receiving packet data transmitted from the relay data transmission device 1513 via a wireless line 1505 by a cellular network, and a data terminal 1522 for processing data received by the destination data transmission device 1514. Prepare.

Next, the operation of the data transmission system will be described. The data transmitted from the data terminal 1521 is packetized with an error detection code added by the originating data transmission device 1511. The packetized data is relayed by the relay data transmission devices 1512 and 1513 in such a manner that reception and transmission are sequentially repeated, and is delivered to the destination data transmission device 1514.

[0005] At this time, if a packet is lost due to an error on a data link that is being delivered, lost information is added to the next packet to be transmitted, and the packet is transmitted sequentially. In addition, the relay data transmission device that has detected the packet loss immediately transmits a retransmission request to the higher-level transmission device,
Upon receiving the retransmission request, the next higher-level transmission device retransmits the lost packet.

[0006]

In the case of the above conventional example, transmission and reception can be performed simultaneously since transmission media forming respective data links are independent of each other. Therefore, even if the relay transmission apparatus transmits a retransmission request at an arbitrary timing, transmission on another data link is not affected.

However, in general, when transmission and reception are performed simultaneously using radio waves, since a strong radio wave is radiated and a radio wave is transmitted and a weak radio wave from a long distance is received at the same time, the transmitted wave may interfere with the received wave. And reception is difficult. This is an example of a so-called perspective problem. Further, when the frequency of the transmission channel is close to the frequency of the reception channel, interference due to signal components leaked from the transmission channel becomes more severe in addition to the perspective problem, and reception becomes more difficult. Of course, if the transmission and reception channels are the same,
Needless to say, reception is very difficult. Therefore, if a retransmission request is transmitted as in the conventional example, transmission may not be possible due to interference with transmission on another data link. In order to avoid such a problem, a careful circuit design for sure reception is required. However, the design and fabrication of such devices is laborious and costly.

In order to reduce the size and cost of each transmission device, it is effective to use only one wireless modem for each transmission device. However, in general, a wireless modem cannot simultaneously perform its transmission and reception functions even if different frequencies are used,
In addition, when the transmission and reception frequencies are switched, they must always be switched at the same time. Therefore, when all the same frequency channels are used between the transmission devices,
If a retransmission request is transmitted as in the conventional example, transmission may not be possible due to collision with transmission on another data link. In addition, when different frequency channels are used between the transmission devices, the relay operation will be broken unless the timing for switching the frequency used by the wireless modem is appropriate.

[0009] Therefore, an object of the present invention is to provide a relay apparatus which does not impede transmission by colliding with transmission on another data link even if a retransmission request is transmitted, and which does not disrupt relay operation. A transmission method and a relay transmission system are provided.

[0010]

According to a first aspect of the present invention, transmission and reception are performed at different times from each other, and the data is sequentially transferred from a transmission transmission device to a reception transmission device via one or more relay transmission devices. A data transmission step in which the transmission transmission apparatus transmits a plurality of data frames to which a frame number has been added to the reception transmission apparatus, and one or more relay transmission apparatuses transmits the data frame. A data transfer step for sequentially transferring;
A retransmission request transmitting step of combining the frame numbers of the data frames that the receiving transmission device has not been able to receive normally into one retransmission request and transmitting the retransmission request to the transmission device, and one or more relay transmission devices sequentially transferring the retransmission request. A retransmission request transfer step, a data retransmission step in which the transmission transmission apparatus collectively retransmits one or more data frames to the reception transmission apparatus in response to the retransmission request, and a data received by the one or more relay transmission apparatuses. And a retransmission data transfer step of sequentially transferring the frames.

As described above, according to the first aspect, even if one of the transmission devices having a transmission right uses the same frequency channel, a data transfer or retransmission request of a certain link is issued. Can avoid collision with data transfer or retransmission requests of other links. In addition, by transferring the data at once, the ratio of data to a control frame such as a retransmission request frame can be increased, and the transfer efficiency can be increased. Further, by shortening the frame length, it is possible to increase the retransmission efficiency on a transmission path having a high error rate, such as wireless communication.

[0012] A second invention is an invention according to the first invention, wherein the data transfer step includes a step in which one or more relay transmission devices transmits the data frame normally received among the data frames to each of the relay transmission devices. Storing in a buffer having, and sequentially transferring the normally received data frames, wherein the retransmission request transfer step includes, from a frame number included in a retransmission request received by one or more relay transmission devices, A step of deleting the frame number of the data frame stored in the buffer of the relay transmission device, and a step of sequentially transferring the retransmission request in which the frame number of the data frame stored in the buffer is deleted, The transmitting data transfer step includes, for each data frame received by one or more relay transmission devices, If there is data frame stored in the buffer transmission device it has, comprises the steps of adding the data frame, and a step of further sequentially transferring a data frame a data frame has been added.

As described above, according to the second aspect of the present invention, the number of data frames transmitted from the transmission device at the time of retransmission can be reduced, so that the time required for retransmission is reduced and the retransmission efficiency is improved. Can be.

[0014] A third invention is an invention according to the second invention, wherein the retransmission request transfer step comprises the step of storing all frame numbers included in the retransmission request received by the relay transmission device in a buffer included in the relay transmission device. Determining whether the data frame is included in the frame number of the data frame stored in the receiving and transmitting apparatus. If it is determined that the data frame is included, one or more data frames are collectively collected in response to the retransmission request. If it is determined that the frame number is not included, the frame number of the data frame stored in the buffer of the relay transmission device is deleted from the frame number included in the retransmission request, and the data is further sequentially transferred. And a step. As described above, according to the third aspect, it is possible to eliminate useless retransmission requests.

A fourth invention is an invention according to the first invention, wherein the relay transmission apparatus has one or more directional antennas, a predetermined transmission / reception direction is initially set, and a data transfer step. A retransmission request transfer step and a retransmission data transfer step, wherein the relay transmission apparatus sets a predetermined reception direction duration Ta at the time of reception, and the relay transmission apparatus sets a transmission / reception direction toward the transmission destination transmission apparatus. And resetting the relay transmission device to the initially set predetermined transmission / reception direction according to the elapse of the reception direction duration time Ta.

As described above, according to the fourth aspect, when the transmission path is a wireless transmission path, a directional antenna is used as the antenna, and the directivity of the antenna is changed according to the receiving direction. This makes it possible to set the transmission / reception direction of the wireless relay transmission device so as to prevent multipath fading. In addition, the receiving direction of the next transmission frame can be set without waiting for a transmission frame that has not been transmitted due to a radio error or the like more than necessary, so that data transfer can be ensured.

A fifth invention is an invention according to the fourth invention, wherein a plurality of directional antennas are provided, and the setting of the transmission / reception direction is performed by switching the plurality of directional antennas. And

As described above, according to the fifth aspect of the present invention, a directional antenna is used as an antenna, and the antenna is switched in accordance with the receiving direction to thereby efficiently prevent multipath fading. The receiving direction can be set.

A sixth invention is an invention according to the first invention, wherein the relay transmission apparatus initializes a predetermined frequency channel among a plurality of transmission / reception frequency channels, executes a data transfer step, a retransmission request The transfer step and the retransmission data transfer step include a step in which the relay transmission apparatus sets a predetermined reception channel duration Ta at the time of reception, and a step of setting a transmission / reception frequency channel for the relay transmission apparatus to communicate with the transmission apparatus of the transmission destination. And a step of resetting the relay transmission apparatus to the initially set predetermined frequency channel according to the elapse of the reception channel duration Ta.

As described above, according to the sixth aspect of the present invention, different frequency channels can be used for communication with the preceding transmission device and communication with the next transmission device, and the frequency channel near the preceding transmission device can be used. There is an interference source near the next transmission device,
Even when the frequency characteristics of the two interference wave sources are different, the throughput can be increased by setting an appropriate frequency channel.

A seventh invention is an invention according to the sixth invention, wherein the setting of the transmission / reception frequency channel maximizes the throughput with the transmission apparatus of the transmission destination among the plurality of transmission / reception frequency channels. It is characterized in that it is performed by selecting a frequency channel.

As described above, according to the seventh aspect, the maximum throughput can be obtained by selecting the optimal frequency channel in each communication section.

An eighth invention is the invention according to the first invention, wherein the data frame and the retransmission request are each further added with transfer expiration date information indicating a predetermined time until the transfer is canceled, and the data transmission is performed. A step of calculating a remaining time until the transfer is canceled for each data frame by sequentially subtracting a transmission time required for one data frame from a predetermined time until the transfer is canceled; Adding the remaining time calculated for each frame as new transfer expiration date information, the data transfer step, the retransmission request transmission step, the retransmission request transfer step, the data retransmission step, and the retransmission data transfer step, The time required from transmission to transmission is the expiration date included in the data frame or retransmission request Calculating the remaining time before canceling the transfer, adding the calculated remaining time as new transfer expiration information, and determining that the new transfer expiration information is negative. And the step of stopping the transmission or the transfer in the case where it has occurred.

As described above, according to the eighth aspect, since each transmission device can grasp the remaining transferable time on the transfer path, it is possible to avoid transfer beyond the transfer valid period.

A ninth invention is an invention according to the eighth invention, wherein the transfer expiration date information is a natural number N when the time required to transmit one frame is set to one. I do.

As described above, according to the ninth aspect, it is possible to increase the data transfer efficiency by reducing the area of the transfer expiration date information added to the transmission frame.

A tenth invention is according to the eighth invention, wherein the relay transmission apparatus has one or more directional antennas, a predetermined transmission / reception direction is initially set, and a data transfer step. A retransmission request transfer step and a retransmission data transfer step, wherein the relay transmission apparatus sets a predetermined reception direction duration Ta using the received transfer expiration information, and the relay transmission apparatus transmits to the transmission apparatus at the transmission destination. The method further includes the steps of: setting a transmission / reception direction toward the transmission direction; and resetting the relay transmission device to a predetermined transmission / reception direction that has been initially set when the reception direction duration Ta elapses.

As described above, according to the tenth aspect, when the transmission path is a wireless transmission path, a directional antenna is used as the antenna, and the directivity of the antenna is changed according to the receiving direction. This makes it possible to set the receiving direction of the wireless relay transmission device so as to prevent multipath fading. Further, the receiving direction of the next transmission frame can be set without waiting more than necessary for a transmission frame that has not been transmitted due to a radio error or the like, so that data transfer can be ensured.

An eleventh invention is an invention according to the eighth invention, wherein the relay transmission apparatus initializes a predetermined frequency channel among a plurality of transmission / reception frequency channels,
The data transfer step, the retransmission request transfer step, and the retransmission data transfer step include a step of setting a predetermined reception channel duration Ta at the time of reception by the relay transmission apparatus, and a step of transmitting and receiving the relay transmission apparatus to communicate with the transmission apparatus of the transmission destination. Setting a frequency channel for use and a step of resetting the relay transmission apparatus to a predetermined frequency channel that has been initialized by the elapse of the reception channel duration Ta.

As described above, according to the eleventh aspect, when the transmission path is a wireless transmission path, different frequency channels can be used for communication with the preceding transmission apparatus and communication with the next transmission apparatus. It is possible to set up an appropriate frequency channel even if there is an interference source near the transmission equipment at the previous stage or the transmission equipment at the next stage, and the two interference sources have different frequency characteristics. Can be raised. In addition, since the reception frequency channel of the next transmission frame can be set without waiting unnecessarily for a transmission frame that has not been transmitted due to a radio error or the like, data transmission can be ensured.

A twelfth invention is an invention according to the first invention, wherein the retransmission request transmitting step retransmits data according to a predetermined time until the transmission transmission apparatus starts the next transmission and a retransmission request. Comparing with the maximum time required for the data transmission, and if the predetermined time until the start of data transmission is shorter, a retransmission request is not performed, and if the predetermined time is longer or the same, Collecting the frame numbers of the data frames that the transmission device could not normally receive into one retransmission request, and transmitting the retransmission request to the transmission device.

As described above, according to the twelfth aspect, in the case where transmission is started at a fixed period in order to guarantee a certain throughput, it occurs because the number of retransmissions cannot be specified depending on the state of the transmission path. The collision between the transmission in the current cycle and the transmission in the next cycle can be avoided beforehand.

A thirteenth invention is a invention according to the twelfth invention, wherein the maximum time required to retransmit data in response to a retransmission request is to add 1 to the number of retransmission frames,
The multiplication value is multiplied by the transfer count and the time required to transmit one frame, and α (where α is a predetermined numerical value determined by the processing capability) is added to the multiplication value. .

As described above, according to the thirteenth aspect, a typical calculation method of the maximum retransmission time in the twelfth aspect is specified. This makes it possible to easily determine whether or not the retransmission request can be transmitted in the reception transmission device, avoid collision between transmission in the current cycle and transmission in the next cycle, and perform calculations in the reception transmission device. It can be done easily.

According to a fourteenth aspect, a system for transmitting and receiving data frames at different times from one another and sequentially transmitting the data frame from the transmission transmission device to the reception transmission device via one or more relay transmission devices is provided. A transmission unit that receives a retransmission request including a frame number of a data frame that the reception transmission unit has not been able to receive normally; and a frame header that extracts a frame number from the retransmission request received by the reception unit. An analysis unit, a data frame generation unit that adds a frame number to transmission data to generate a transmission data frame, and a transmission unit that transmits the transmission data frame, wherein the reception transmission device receives the data frame A receiving unit; a frame header analyzing unit for extracting a frame number from a data frame received by the receiving unit; The transmission device includes a retransmission request frame generation unit that generates a retransmission request including a frame number of a data frame that has not been normally received, and a transmission unit that transmits the retransmission request.The relay transmission device transmits the data frame or the retransmission request. A receiving unit that receives, and a transmitting unit that transmits a data frame or a retransmission request received by the receiving unit,
If the receiving transmission device cannot receive all of the plurality of data frames transmitted by the transmitting transmission device, a retransmission request is transmitted by the receiving transmission device, and the transmission transmission device responds to the retransmission request by using one or more retransmission requests. Are collectively retransmitted to the receiving and transmitting apparatus.

As described above, according to the fourteenth aspect, even if one of the transmission apparatuses having the transmission right uses the same frequency channel, a data transfer or retransmission request of a certain link is issued. Can avoid collision with data transfer or retransmission requests of other links. In addition, by transferring the data at once, the ratio of data to a control frame such as a retransmission request frame can be increased, and the transfer efficiency can be increased. Further, by shortening the frame length, it is possible to increase the retransmission efficiency on a transmission path having a high error rate, such as wireless communication.

A fifteenth invention is a invention according to the fourteenth invention, wherein the relay transmission device stores a normally received data frame, and when the transmission transmission device retransmits the data frame, A retransmission frame buffer for generating a transmission data frame by adding a data frame further stored to the data frame and a frame number included in the received retransmission request are stored in the retransmission frame buffer. A retransmission request frame reconstructing unit that deletes a frame number of the data frame.

As described above, according to the fifteenth aspect, it is possible to reduce the number of data frames transmitted from the transmission device at the time of retransmission, so that the time required for retransmission is reduced and the retransmission efficiency is improved. Can be.

A sixteenth invention is an invention according to the fourteenth invention, wherein the relay transmission apparatus controls one or more directional antennas for transmitting and receiving signals, and transmits and receives signals by controlling the directional antennas. And an antenna control unit for setting the direction to a predetermined direction and resetting to the initially set predetermined transmission / reception direction when a predetermined reception direction duration Ta elapses.

As described above, according to the sixteenth aspect, when the transmission path is a wireless transmission path, a directional antenna is used as the antenna, and the directivity of the antenna is changed according to the receiving direction. This makes it possible to set the transmission / reception direction of the wireless relay transmission device so as to prevent multipath fading. In addition, the receiving direction of the next transmission frame can be set without waiting for a transmission frame that has not been transmitted due to a radio error or the like more than necessary, so that data transfer can be ensured.

A seventeenth invention is a invention according to the fourteenth invention, wherein the relay transmission apparatus comprises: a plurality of directional antennas for transmitting and receiving signals; and an antenna switch for selectively switching the plurality of directional antennas. And an antenna control unit that controls the antenna switching unit to set the signal transmission / reception direction, and resets the transmission direction to the initially set predetermined transmission / reception direction when a predetermined reception direction duration Ta elapses.

As described above, according to the seventeenth aspect, a directional antenna is used as an antenna, and the antenna is switched in accordance with the receiving direction, whereby the multi-path fading can be efficiently prevented. The receiving direction can be set.

An eighteenth invention is according to the fourteenth invention, wherein the relay transmission apparatus sets a frequency channel for transmitting / receiving a signal among a plurality of transmission / reception frequency channels, and sets a predetermined frequency channel duration. The apparatus further comprises a frequency channel control unit for resetting to a predetermined frequency channel that has been initially set when Ta has elapsed, wherein the transmission unit and the reception unit transmit and receive signals using the frequency channel set by the frequency channel control unit. It is characterized by.

As described above, according to the eighteenth aspect, when the transmission path is a wireless transmission path, different frequency channels can be used for communication with the preceding transmission apparatus and communication with the next transmission apparatus. It is possible to set up an appropriate frequency channel even if there is an interference source near the transmission equipment at the previous stage or the transmission equipment at the next stage, and the two interference sources have different frequency characteristics. Can be raised. In addition, since the reception frequency channel of the next transmission frame can be set without waiting unnecessarily for a transmission frame that has not been transmitted due to a radio error or the like, data transmission can be ensured.

A nineteenth invention is a invention according to the fourteenth invention, wherein the transmission transmission device obtains a required transmission time per data frame from transfer expiration date information indicating a predetermined time until the transfer is canceled. , The remaining time until the transfer is canceled for each data frame is calculated and used as new transfer expiration date information. If the new transfer expiration date information becomes negative, transmission is performed. The data transmission apparatus further includes a transfer expiration date control unit that controls to stop the transmission, and a transfer expiration date addition unit that adds the transfer expiration date information to the data frame. By sequentially subtracting from the transfer expiration date information included, the remaining time until the transfer is canceled is calculated and used as new transfer expiration date information. A transfer time limit control section for controlling to stop the transmission if the expiration date information becomes negative,
A transfer expiration date adding unit for adding transfer expiration date information to the retransmission request, wherein the relay transmission device sequentially subtracts a required time from reception to transmission from the data expiration date information included in the data frame or the retransmission request. The transfer expiration time control unit that calculates the remaining time until the transfer is canceled and uses the calculated time as new transfer expiration information, and stops transmission when the transfer expiration information becomes negative. And a transfer expiration date adding unit for adding transfer expiration date information to the data frame or the retransmission request.

As described above, according to the nineteenth aspect, since each transmission device can grasp the remaining transferable time on the transfer path, it is possible to avoid transfer beyond the transfer valid period. .

A twentieth invention is the invention according to the nineteenth invention, wherein the transfer expiration date information is a natural number N, where the time required to transmit one frame is one. I do. As described above, according to the nineteenth aspect, it is possible to increase the data transfer efficiency by reducing the area of the transfer expiration date information added to the transmission frame.

A twenty-first invention is an invention according to the nineteenth invention, wherein the relay transmission apparatus controls one or more directional antennas for transmitting and receiving signals, and transmits and receives signals by controlling the directional antennas. Direction, and a predetermined receiving direction duration Ta is set using the received transfer expiration information,
And an antenna control unit for resetting to a predetermined transmission / reception direction which has been initially set when the reception direction duration Ta elapses.

As described above, according to the twenty-first aspect, when the transmission path is a wireless transmission path, a directional antenna is used as the antenna, and the directivity of the antenna is changed according to the receiving direction. This makes it possible to set the receiving direction of the wireless relay transmission device so as to prevent multipath fading. Further, the receiving direction of the next transmission frame can be set without waiting more than necessary for a transmission frame that has not been transmitted due to a radio error or the like, so that data transfer can be ensured.

A twenty-second invention is an invention according to the nineteenth invention, wherein the relay transmission device sets a frequency channel for transmitting / receiving a signal among a plurality of frequency channels for transmission / reception, and sets the received transfer enable A frequency channel control unit that sets a predetermined frequency channel duration Ta using the time limit information, and resets the frequency channel to the initially set predetermined frequency channel when the frequency channel duration Ta elapses; Transmits and receives signals using a frequency channel set by the frequency channel control unit.

As described above, according to the twenty-second aspect, when the transmission path is a wireless transmission path, different frequency channels can be used for communication with the preceding transmission apparatus and communication with the next transmission apparatus. It is possible to set up an appropriate frequency channel even if there is an interference source near the transmission equipment at the previous stage or the transmission equipment at the next stage, and the two interference sources have different frequency characteristics. Can be raised. In addition, since the reception frequency channel of the next transmission frame can be set without waiting unnecessarily for a transmission frame that has not been transmitted due to a radio error or the like, data transmission can be ensured.

According to a twenty-third aspect, a transmission transmission apparatus for relaying a data frame by performing transmission and reception at mutually different times and sequentially transferring the data frame to one or more reception transmission apparatuses via one or more relay transmission apparatuses. A receiving unit that receives a retransmission request including a frame number of a data frame that the receiving transmission device has not been able to receive normally; a frame header analyzing unit that extracts a frame number from the retransmission request received by the receiving unit; A data frame generation unit that generates a data frame for transmission by adding a frame number to data, and a transmission unit that transmits a data frame for transmission, so that the reception transmission device can receive all of the transmitted data frames. If not, a retransmission request is transmitted by the receiving transmission apparatus, and one or more retransmission requests are transmitted in response to the transmitted retransmission request. And wherein the retransmitting summarizes data frame to the receiving transmission apparatus.

As described above, according to the twenty-third aspect, even if one of the transmission apparatuses having the transmission right uses the same frequency channel, a data transfer or retransmission request of a certain link is issued. Can avoid collision with data transfer or retransmission requests of other links. In addition, by transferring the data at once, the ratio of data to a control frame such as a retransmission request frame can be increased, and the transfer efficiency can be increased. Further, by shortening the frame length, it is possible to increase the retransmission efficiency on a transmission path having a high error rate, such as wireless communication.

The twenty-fourth invention is an invention according to the twenty-third invention, wherein the transmission transmission device obtains a required transmission time per data frame from transfer expiration date information indicating a predetermined time until the transfer is canceled. , The remaining time until the transfer is canceled for each data frame is calculated and used as new transfer expiration date information. If the new transfer expiration date information becomes negative, transmission is performed. It further includes a transfer expiration date control unit that controls to stop the transfer, and a transfer expiration date adding unit that adds the transfer expiration date information to the data frame.

As described above, according to the twenty-fourth aspect, the number of data frames sent from the transmission device at the time of retransmission can be reduced, so that the time required for retransmission is reduced and the retransmission efficiency is improved. Can be.

A twenty-fifth aspect of the present invention is a receiving transmission apparatus for relaying a data frame by performing transmission and reception at different times from each other, and sequentially transferring the data frame from the transmitting transmission apparatus via one or more relay transmission apparatuses. A receiving unit for receiving a data frame, a frame header analyzing unit for extracting a frame number from the data frame received by the receiving unit, and a retransmission including a frame number of the data frame that the receiving / transmitting device cannot normally receive. A retransmission request frame generation unit that generates a request, and a transmission unit that transmits a retransmission request, and when not all of the plurality of data frames transmitted by the transmission transmission device have been received, transmits a retransmission request, The transmitting transmission apparatus responds to the retransmission request and collectively retransmits one or more data frames.

As described above, according to the twenty-fifth aspect, even when one of the transmission apparatuses having the transmission right uses the same frequency channel, a data transfer or retransmission request of a certain link is issued. Can avoid collision with data transfer or retransmission requests of other links. In addition, by transferring the data at once, the ratio of data to a control frame such as a retransmission request frame can be increased, and the transfer efficiency can be increased. Further, by shortening the frame length, it is possible to increase the retransmission efficiency on a transmission path having a high error rate, such as wireless communication.

A twenty-sixth invention is an invention according to the twenty-fifth invention, wherein the receiving and transmitting apparatus sequentially subtracts a required time from reception to transmission from transfer expiration date information included in the data frame. By calculating the remaining time until the transfer is canceled to obtain new transfer expiration date information, a transfer expiration date control unit that controls to stop transmission when the transfer expiration date information becomes negative, And a transfer expiration date adding unit for adding the transfer expiration date information to the retransmission request.

As described above, according to the twenty-sixth aspect, the number of data frames sent from the transmission device at the time of retransmission can be reduced, so that the time required for retransmission is reduced and the retransmission efficiency is improved. Can be.

A twenty-seventh aspect of the present invention is a relay transmission apparatus for performing transmission and reception at mutually different times and relaying and transmitting a data frame by sequentially transferring the data frame from a transmission transmission apparatus to a reception transmission apparatus. A receiving unit that receives a retransmission request including a frame number of a data frame or a data frame that cannot be normally received by the receiving transmission device; and a transmitting unit that transmits the data frame or the retransmission request received by the receiving unit. If the receiving transmission device cannot receive all of the plurality of data frames transmitted by the transmission device, a retransmission request is transmitted by the receiving transmission device.
One or more data frames are collectively retransmitted to the receiving and transmitting apparatus.

As described above, according to the twenty-seventh aspect, even if one of the transmission devices having the transmission right uses the same frequency channel, a data transfer or retransmission request of a certain link is issued. Can avoid collision with data transfer or retransmission requests of other links. In addition, by transferring the data at once, the ratio of data to a control frame such as a retransmission request frame can be increased, and the transfer efficiency can be increased. Further, by shortening the frame length, it is possible to increase the retransmission efficiency on a transmission path having a high error rate, such as wireless communication.

A twenty-eighth invention is an invention according to the twenty-seventh invention, wherein the relay transmission device sequentially subtracts a required time from reception to transmission from transfer expiration date information included in the data frame or the retransmission request. By doing this, the remaining time until the transfer is canceled is calculated and used as new transfer expiration date information, and if the transfer expiration date information becomes negative, the transmission is controlled to stop transmission. And a transfer expiration date adding unit for adding transfer expiration date information to the data frame or the retransmission request.

As described above, according to the twenty-eighth aspect, the number of data frames sent from the transmission device at the time of retransmission can be reduced, so that the time required for retransmission is reduced and the retransmission efficiency is improved. Can be.

[0064]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIGS. 1 to 3 are diagrams showing a configuration of a data transmission system according to a first embodiment of the present invention. FIG. 1 is a diagram illustrating a configuration of a relay transmission device 10 installed between a reception transmission device and a transmission transmission device to extend a transmission distance. FIG.
FIG. 2 is a diagram illustrating a configuration of a reception transmission device 20 that receives data transmitted from a transmission transmission device. FIG. 3 is a diagram illustrating a configuration of the transmission transmission device 30 that transmits transmission data to the reception transmission device. In FIG. 1 to FIG.
0, the transmission transmission device 30, and the relay transmission device 10 are connected via a transmission line 40. Hereinafter, the configuration and operation of each device will be described.

In FIG. 1, a relay transmission device 10 demodulates a transmission wave on a transmission path to generate a transmission frame such as a polling frame, a retransmission request frame, a data frame, and the like, and adds the data to the transmission frame. An error detection unit 102 that determines whether an error exists in a transmission frame using the detected error detection code, a frame header analysis unit 103 that analyzes a frame type and a destination in the transmission frame, and a relay control that controls each unit. Unit 104, a retransmission frame buffer 105 for storing transmission frames for retransmission, a relay buffer 106 for storing transmission frames at the time of relay, a destination change unit 107 for rewriting destinations in transmission frames, and an error detection code for transmission frames. And an error detection code adding unit 108 for calculating and adding Data transmission unit 10 for transmitting the transmission path
9, a retransmission request frame reconstructing unit 110 for changing the retransmission requested frame number in the retransmission request frame
And

The data receiving section 101 and the data transmitting section 109 are typically included in a single modem 100. Therefore, the data receiving unit 101 and the data transmitting unit 109 cannot transmit and receive at the same time. However, the data receiving unit 101 and the data transmitting unit 109
Need not be included in a single modem, as long as it is not possible to perform simultaneous transmission and reception in order to avoid the near-far problem and interference between adjacent transmission and reception channels as described above.

Next, the operation of the relay transmission device 10 will be described. In the relay transmission device 10, the data receiving unit 10
1 receives a transmission frame. The error detection unit 102 determines whether the received transmission frame is a normal frame. If an error is detected in the frame,
The frame is discarded by the error detection unit 102.
If no error is detected, the frame information of the frame is analyzed by the frame header analysis unit 103.

If it is determined that the analyzed frame is a polling frame addressed to its own terminal, the frame header analysis unit 103 outputs a notification to that effect to the relay control unit 104. The relay control unit 104 clears the retransmission frame buffer 105 and the relay buffer 106. Also,
The frame header analysis unit 103 inputs the analyzed frame to the destination change unit 107. The input frame is
The destination is changed by the destination changing unit 107 to the transmission device adjacent to the transmission side, and is input to the error detection code adding unit 108. The input frame is transmitted from the data transmitting unit 109 after an error detecting code is added by the error detecting code adding unit 108.

When it is determined that the frame analyzed by the frame header analysis unit 103 is a data frame addressed to the own terminal, the frame header analysis unit 103 outputs a notification to that effect to the relay control unit 104. Further, the frame header analysis unit 103 inputs the analyzed frame to the destination change unit 107. The destination of the input frame is rewritten by the destination changing unit 107 to the transmission device adjacent to the receiving side, and is input to the error detection code adding unit 108. The frame is added to the error detection code by the error detection code adding unit 108 and then stored in the retransmission frame buffer 105. On the other hand, the frame is also stored in the relay buffer 106. Further, when detecting the end of the reception of a series of data frames, the relay control unit 104 controls the data transmission unit 109 to transmit the data stored in the relay buffer 106, and clears the relay buffer 106.

When it is determined that the frame analyzed by the frame header analysis unit 103 is a retransmission request frame addressed to the own terminal, the frame header analysis unit 103 outputs a notification to that effect to the relay control unit 104. Also, the retransmission request frame is transmitted to retransmission request frame reconstructing section 110.
Is input to The relay control unit 104 controls the relay buffer 10
6 is cleared, it is determined whether the data frame requested to be retransmitted is stored in the retransmission frame buffer 105, and the stored data frame is transferred to the relay buffer 1
06. Further, the relay control unit 104 determines the frame number of the data frame not stored in the retransmission frame buffer 105 by using the retransmission request frame reconfiguration unit 11.
Notify 0.

The retransmission request frame reconstructing section 110 converts the retransmission request frame
05 is input to the destination change unit 107 after removing the frame number existing in the destination 05. The destination change unit 107 changes the destination of the input retransmission request frame to the destination of the transmission device on the transmission side, and inputs the destination to the error detection code adding unit 108. The input retransmission request frame is input to the error detection code adding unit 108
Then, after adding an error detection code, the data is transmitted by the data transmission unit 109.

In FIG. 2, the receiving and transmitting apparatus 20 includes a polling cycle counting section 201 for measuring a time and issuing a polling transmission command at regular time intervals, a polling frame generating section 202 for generating a polling frame, an error in the transmission frame. An error detection code addition unit 203 for calculating and adding a detection code; a data transmission unit 204 for modulating a transmission frame and sending it as a transmission wave onto a transmission line; a demodulation of the transmission wave on the transmission line to generate a polling frame and a retransmission request. A data receiving unit 205 for generating a transmission frame such as a frame or a data frame; an error detection unit 206 for determining whether an error exists in the transmission frame by using an error detection code added to the received transmission frame; Frame header analysis unit 207 that analyzes the type and destination of the frame in the frame
After storing the data frames, the frame order reconstructing unit 208 reads out in order of the frame number according to the instruction, extracts and outputs the data part, and the retransmission control unit 2 that controls the retransmission of the data frame that could not be received normally.
09, and a retransmission request frame generation unit 210 that generates a retransmission request frame including the frame number of the data frame for which retransmission is requested.

The data receiving unit 205 and the data transmitting unit 204 are typically included in a single modem 200. However, if they cannot be transmitted and received simultaneously, they are necessarily included in a single modem. It is not necessary as described above.

Next, the operation of the receiving and transmitting apparatus 20 will be described. In the reception transmission device 20, the polling cycle counting unit 201 issues a polling transmission command at regular time intervals to the polling frame generation unit 202 and the retransmission control unit 209.
Enter Upon receiving the polling transmission command, the polling frame generation unit 202 generates a polling frame addressed to the adjacent relay transmission device, and outputs the polling frame to the error detection code adding unit 2.
Enter 03. The input polling frame is transmitted by the data transmission unit 204 after the error detection code is added by the error detection code addition unit 203.

The error detection unit 206 determines whether the transmission frame received by the data reception unit 205 is a normal frame. When an error is detected in a frame, the frame is discarded by the error detection unit 206. If no error is detected, the frame header analysis unit 207 analyzes the information of the frame. Frame header analysis unit 20
If the frame analyzed by 7 is determined to be a data frame addressed to the own terminal, the frame is stored in the frame order reconstruction unit 208. After receiving a series of data, retransmission control section 209 sets frame order reconfiguration section 208
It is detected whether or not there is an unarrived data frame in the transmission data stored in. If there are no unarrived data frames, the retransmission control unit 209 outputs the data frames stored in the frame order reconfiguration unit 208 in order according to the frame number as it is, and sets the data frames as the received data output.

When there is an unarrived data frame, the retransmission control unit 209 calculates the time from the timing of the polling transmission command input by the polling cycle counting unit 201 until the next polling transmission. The time is given by the following formula,
If the value is larger than the value obtained by calculating (the number of retransmission frames + 1) × (the number of transfers) × (the time required for transmitting one frame) + α (where α is a constant determined by the processing capacity), the retransmission control unit 209 Is a retransmission request frame generation unit 21
For 0, control is performed such that a retransmission request frame storing the frame number of an unarrived data frame is created for the adjacent relay transmission device. The created retransmission request frame is transmitted by the data transmission unit 204 after the error detection code is added by the error detection code addition unit 203. On the other hand, if the time until the next polling transmission is smaller than the value obtained by calculating the above equation, the retransmission control unit 209
Cancels the transmission of the retransmission request frame.

In FIG. 3, a transmission transmission device 30 demodulates a transmission wave on a transmission path to generate a transmission frame such as a polling frame, a retransmission request frame, a data frame, and the like, and adds the data to the transmission frame. An error detection unit 302 that determines whether an error exists in a transmission frame using the obtained error detection code, a frame header analysis unit 303 that analyzes a frame type and a destination in the transmission frame, and a transmission control unit that controls each unit. 304, a retransmission frame buffer 3 for accumulating transmission frames for retransmission
05 and a transmission data buffer 30 for storing transmission data.
6, a data frame generation unit 307 that adds a frame number, an error detection code, and a destination area to data to form a data frame, and an error detection code addition unit 308 that calculates and adds an error detection code of a transmission frame. , A data transmission unit 309 that modulates a transmission frame and transmits the transmission frame as a transmission wave onto a transmission path, and a retransmission control unit 310 that controls retransmission.

The data receiving unit 301 and the data transmitting unit 309 are typically included in a single modem 300, but if they cannot be transmitted and received simultaneously, they are necessarily included in a single modem. It is not necessary as described above.

Next, the operation of the transmission device 30 will be described. In the transmission device 30, the data receiving unit 30
1 receives a transmission frame. The error detection unit 302 determines whether or not the received transmission frame is a normal frame. If an error is detected in the frame,
The error detector 302 discards the frame.
If no error is detected, the frame information of the frame is analyzed by the frame header analysis unit 303.

If it is determined that the analyzed frame is a polling frame addressed to its own terminal, frame header analysis section 303 outputs a notification to that effect to transmission control section 304 and retransmission control section 310. Upon receiving the notification, the retransmission control unit 310 clears the retransmission frame buffer 305. After that, the transmission control unit 304 sends the data frame generation unit 307 to the transmission data buffer 306.
Is controlled to output data for the specified number of frames. The data output from the transmission data buffer 306 is framed by the data frame generation unit 307 by adding a frame number to an adjacent relay transmission device in order. The framed data is added with an error detection code by an error detection code addition unit 308, then stored in a retransmission frame buffer 305, and transmitted from a data transmission unit 309.

If it is determined that the frame analyzed by the frame header analysis unit 303 is a retransmission request frame addressed to the own terminal, the frame header analysis unit 303 outputs a notification to that effect to the retransmission control unit 310 and , The retransmission request frame is input to retransmission control section 310. The retransmission control unit 310 extracts a frame number from the input retransmission request frame and stores a data frame corresponding to the frame number in the retransmission frame buffer 3.
05 to the data transmission unit 309. The output data is transmitted by the data transmission unit 309.

FIG. 4 is a diagram showing a transfer sequence in the data transmission system according to the present embodiment. In the data transmission system according to the present embodiment, it is assumed that each device is performing wireless data transmission in the same frequency band. Further, it is assumed that polling generated from the receiving transmission device in the present data transmission system is transferred in the order of the second relay transmission device and the first relay transmission device, and reaches the transmission transmission device.

In FIG. 4, the transmitting transmission apparatus that has received the polling transmits a data frame having a frame number from 1 to 7 to the first relay transmission apparatus. Note that an x mark in the figure indicates that an error has occurred in the data frame. The data frame marked with “x” is discarded by the receiving transmission device, the first relay transmission device, or the second relay transmission device.

The first relay transmission apparatus stores the normally received first, second, fifth, sixth, and seventh data frames in the retransmission frame buffer as described above, Send to relay transmission device. The second relay transmission device includes:
The normally received first, second, fifth and seventh data frames are stored in the retransmission frame buffer and transmitted to the receiving and transmitting apparatus.

The receiving and transmitting apparatus stores the first, second, fifth, and seventh data frames in the frame order reconstruction unit 208 as described above, and the third,
It is determined that the fourth and sixth data frames are missing.

Here, assuming that one transmission frame transmission time is T, the polling transmission period is 40T, and the constant α of the processing capability is 0. Since the number of already transmitted frames is as described above and the total number is 19, it can be calculated that the time until the next polling is 21T. Therefore, when (the number of retransmission frames + 1) × (the number of transfers) × (the time required for transmitting one frame) + α is calculated, (3 + 1)
× 3 × T + 0 = 12T. Therefore, since the time until the next polling is longer, generation of a retransmission request frame requesting retransmission of the third, fourth, and sixth data frames is instructed. The retransmission request frame generated by the instruction is transmitted to the second relay transmission device.

In the retransmission frame buffer of the second relay transmission device receiving the retransmission request frame,
No. 4, 4 and 6 data frames are not stored. Therefore, the retransmission request frame is directly transmitted to the first relay transmission device.

The sixth data frame is stored in the retransmission frame buffer of the first relay transmission device that has received the retransmission request frame. Therefore, as described above, the sixth data frame is stored in the relay buffer. Further, as described above, the frame number of the sixth data frame is deleted, and a retransmission request frame requesting retransmission of the third and fourth data frames is generated and transmitted to the transmission device.

The transmission transmission device receives the retransmission request and transmits the third and fourth data frames to the first relay transmission device. The first relay transmission device stores the third and fourth data frames in the retransmission frame buffer,
The third data frame is added to generate the third, fourth, and sixth data frames and transmitted to the second relay transmission device. The second relay transmission device stores the third, fourth, and sixth data frames in the retransmission frame buffer, and further transmits the data frames to the reception transmission device.

The receiving and transmitting apparatus converts the normally received No. 4 and No. 6 data frames into the frame order reconstruction unit 20.
8 and the retransmission control unit 209 determines that the third data frame is missing.

Here, the time until the next polling is 10T.
(The number of retransmission frames + 1) × (the number of transfers) × (1
When calculating the time required for frame transmission) + α, (1+
1) × 3 × T + 0 = 6T Therefore, since the time until the next polling is longer, generation of a retransmission request frame requesting retransmission of the third data frame is instructed, and the generated retransmission request frame is transmitted to the second relay transmission device.

In the second relay transmission device, since the third data frame is stored in the retransmission frame buffer,
The third data frame is stored in the relay buffer. Next, all data frames requested in the retransmission request frame are accumulated in the retransmission frame buffer. Therefore, the third data frame is transmitted from the second relay transmission device to the reception transmission device without sending the retransmission request frame to the first relay transmission device.

The receiving and transmitting apparatus stores the normally received third data frame in the frame order reconstructing section 208, identifies that the data frame has been received by the retransmission control section 209, 208 is instructed to output data. Frame order reconstruction unit 208
Reads out the stored data frames in the order of frame numbers and outputs the data frames.

As described above, according to the data transmission system of the present embodiment, the order in which transmission frames are transmitted is sequentially passed for each transmission device, and data transmission and error retransmission are performed. As a result, even when transmission on one data link affects transmission on another data link, such as a wireless transmission path, data transfer by relay can be performed without being affected. In addition, efficient retransmission can be performed on a transmission path having a high error rate.

In the data transmission system according to the present embodiment, a two-stage relay using two relay transmission devices has been described. However, the data transmission system according to the present embodiment may be an M-stage relay (where M is a natural number) using M relay transmission devices. Also in this case, the data transmission system according to the present embodiment can exert the same effect.

In the data transmission system according to the present embodiment, the description has been made assuming that the transmission path is a wireless transmission path. However, in the data transmission system according to the present embodiment, for example, a wired transmission path in which each transmission device is connected in a bus type may be used. Also in this case, the data transmission system according to the present embodiment can exert the same effect.

(Second Embodiment) FIGS. 5 to 7 are diagrams showing a configuration of a data transmission system according to a second embodiment of the present invention. FIG. 5 is a diagram showing a configuration of the relay transmission device 50 installed between the reception transmission device and the transmission transmission device to extend the transmission distance. FIG. 6 is a diagram illustrating a configuration of the reception transmission device 60 that receives data transmitted from the transmission transmission device. FIG. 7 is a diagram illustrating a configuration of the transmission transmission device 70 that transmits transmission data to the reception transmission device. 5 to 7, the reception transmission device 60, the transmission transmission device 70, and the relay transmission device 50
Connected through.

The data transmission system according to the present embodiment
Since the configuration is almost the same as that of the data transmission system according to the first embodiment, the description of the common configuration will be omitted, and differences will be described.

In FIG. 5, the relay transmission device 50
Has a transfer expiration time control unit 501 that retains the transfer expiration time and decrements the transfer expiration time by 1 each time the transmission of one transmission frame elapses. The difference is that a transfer expiration date adding unit 502 that adds transfer expiration date information to a frame is further provided.

[0100] In FIG.
Has a transfer expiration date control unit 601 that retains the transfer expiration date and decrements the transfer expiration date by one each time the transmission of one transmission frame elapses. The difference is that a transfer expiration date adding unit 602 for adding transfer expiration date information to a frame is further provided.

In FIG. 7, the transmission transmission apparatus 70
Has a transfer expiration date control unit 701 that holds the transfer expiration date and decrements the transfer expiration date by 1 each time the time for transmitting one transmission frame elapses. The difference is that a transfer expiration date adding unit 702 that adds transfer expiration date information to a frame is further provided.

First, referring to FIG.
The operation of 0 will be described. In the relay transmission device 50, the data receiving unit 101 receives a transmission frame.
The error detection unit 102 determines whether the received transmission frame is a normal frame. When an error is detected in a frame, the frame is discarded by the error detection unit 102. If no error is detected, the frame information of the frame is analyzed by the frame header analysis unit 103.

If the frame is analyzed to be addressed to the own terminal, the frame header analysis unit 103 subtracts 1 from the transfer expiration date information in the frame and stores it in the transfer expiration date control unit 501. . Further, the frame header analysis unit 103 notifies the relay control unit 104 of the type of the analyzed frame.

When the analyzed frame is notified that the frame is a polling frame, the relay control unit 104 sets the retransmission frame buffer 105 and the relay buffer 106
Clear Further, the relay control unit 104 controls the destination change unit 107 to rewrite the destination of the polling frame to an adjacent transmission device on the transmission side and send the polling frame to the transfer expiration date adding unit 502.

The transfer expiration date adding unit 502 adds the transfer expiration date information stored in the transfer expiration date control unit 501 to the polling frame. The polling frame to which the transfer expiration date information is added is sent to the error detection code adding unit 10.
8, an error detection code is further added, and transmitted from the data transmission unit 109.

If the analyzed frame is notified that the frame is a data frame, the relay control unit 104 causes the destination change unit 107 to rewrite the destination of the data frame to a transmission device adjacent to the receiving side, and The frames are stored in the relay buffer 106 while being accumulated in the retransmission frame buffer 105.

Further, when the relay control unit 104 detects the end of the reception of a series of data frames, the relay control unit 104 controls the data frames stored in the relay buffer 106 to be transmitted to the transfer expiration date adding unit 502, and transmits the data frames. At the end of the process, the relay buffer 106 is cleared.

The transfer expiration date adding unit 502 is a transfer expiration date control unit 501 that is decremented by one for each data frame.
Is added to the corresponding data frame. The data frame to which the transfer expiration date information has been added is further added with an error detection code by the error detection code adding section 108 and transmitted from the data transmitting section 109.

When the analyzed frame is notified that the frame is a retransmission request frame, the relay control unit 104 clears the relay buffer 106, and the data frame requested to be retransmitted exists in the retransmission frame buffer 105. To determine whether the data frame exists
6 is stored.

Further, relay control section 104 notifies retransmission request frame reconstructing section 110 of the frame number existing in retransmission frame buffer 105. Relay control unit 10
4 is based on the retransmission request frame input from the frame header analysis unit 103 to the retransmission request frame reconfiguration unit 110,
Retransmission request frame reconstructing section 110 so as to remove the frame number existing in retransmission frame buffer 105
Control. The retransmission request frame is transmitted to the destination change unit 10.
7 is input. The relay control unit 104 includes the destination change unit 10
7, the frame is changed to the destination of the transmission apparatus on the transmission side, and is controlled so as to be input to the transfer expiration date adding section 502.

The transfer expiration date adding unit 502 responds to the input retransmission request frame by a transfer expiration date control unit 501.
The transfer expiration date information notified by the notification is added. The retransmission request frame to which the transfer expiration date information has been added is further added with an error detection code by the error detection code adding section 108 and transmitted from the data transmitting section 109.

The transfer expiration date control unit 501 decrements the stored transfer expiration date by one each time the time for transmitting one transmission frame elapses. Here, when the transfer expiration date becomes less than 0, the transfer expiration date control unit 501
Outputs a notification to that effect to the relay control unit 104. The relay control unit 104 that has received the notification controls each unit so as to cancel the transmission of the transmission frame.

Next, with reference to FIG.
The operation of 0 will be described. In the receiving transmission device 60, the polling cycle counting unit 201
It instructs the polling frame generation unit 202 to issue a polling transmission command. Further, the polling cycle counting unit 201 stores the value of the quotient obtained by dividing the polling cycle by the time required for transmitting one transmission frame as transfer expiration date information in the transfer expiration date control unit 601. Transfer expiration date control unit 601
Notifies the transfer expiration date information to the transfer expiration date adding unit 602.

Upon receiving the polling transmission command, polling frame generation section 202 generates a polling frame addressed to the adjacent relay transmission device and sends it to transfer expiration date adding section 602. The transfer expiration date adding unit 602 adds the transfer expiration date information notified by the transfer expiration date control unit 601 to the polling frame. The polling frame to which the transfer expiration date information has been added is further added with an error detection code by the error detection code addition section 203 and transmitted from the data transmission section 204.

The data receiving section 205 receives a transmission frame transmitted from an adjacent transmission device. The error detection unit 206 determines whether the transmission frame received by the data reception unit 205 is a normal frame. If an error is detected in the frame, the error detection unit 206
Discards the frame. If no error is detected, the frame is sent to the frame header analysis unit 20.
7, the frame information is analyzed.

If the frame is analyzed as a data frame addressed to the own terminal, the frame header analysis unit 2
In step 07, the transfer expiration date information in the frame is decremented by 1 and stored in the transfer expiration date control unit 601. The stored transfer expiration date information is transmitted to the transfer expiration date adding unit 602.
Will be notified. Further, the frame header analysis unit 207
Notifies the retransmission control unit 209 of the arrival of the frame, and stores the frame in the frame order reconstruction unit 208.

After a series of data is received, retransmission control section 209 detects an unarrived data frame in the received data. If there is no unarrived data frame, the retransmission control unit 209 controls the data to be output from the frame order reconfiguration unit 208 in order according to the frame number, and determines the output data as a received data output. I do.

When there is an unarrived data frame, the retransmission control unit 209 sends the retransmission request frame generation unit 210 to the adjacent relay transmission apparatus storing the frame number of the unarrived data frame. A request frame is created, and the retransmission request frame is sent to the transfer expiration date adding unit 6.
02 is controlled.

The transfer expiration date adding unit 602 adds the transfer expiration date information notified from the transfer expiration date control unit 601 to the retransmission request frame. The retransmission request frame to which the transfer expiration date information has been added is further added with an error detection code by the error detection code adding section 203 and transmitted from the data transmission section 204.

The transfer expiration date control unit 601 decrements the stored transfer expiration date by one each time the time for transmitting one transmission frame elapses. Here, when the transfer expiration date becomes less than 0, the transfer expiration date control unit 601 outputs a notice to that effect to the retransmission control unit 209. Upon receiving the notification, the retransmission control unit 209 controls each unit so as to cancel transmission of the transmission frame.

Next, with reference to FIG.
The operation of 0 will be described. In the transmission device 70, the data receiving unit 301 receives a transmission frame.
The error detection unit 302 determines whether the received transmission frame is a normal frame. If an error is detected in the frame, the frame is discarded by the error detection unit 302. If no error is detected, the frame information of the frame is analyzed by the frame header analysis unit 303.

If the analyzed frame is determined to be a polling frame addressed to the own terminal, the frame header analysis unit 303 subtracts 1 from the transfer expiration date information in the frame, and then sends it to the transfer expiration date control unit 701. Store. The stored transfer expiration date information is stored in a transfer expiration date adding unit 702.
To be notified. Further, the frame header analysis unit 303
Notifies the transmission control unit 304 of the arrival of the polling frame.

After being notified of the arrival of the polling frame, the transmission control unit 304 clears the retransmission frame buffer 305 and thereafter transmits the specified number of frames to the transmission data buffer 30.
Data is read from 6. The read data is framed by the data frame generation unit 307 by adding a frame number to an adjacent relay transmission device in order. The transmission control unit 304 sends the framed data to the transfer expiration date adding unit 702 while storing the framed data in the retransmission frame buffer 305.

The transfer expiration date adding unit 702 adds the transfer expiration date information notified from the transfer expiration date control unit 701 to the data frame. The data frame to which the transfer expiration date information has been added is further added with an error detection code by an error detection code adding
09 is transmitted.

If the analyzed frame is determined to be a retransmission request frame addressed to the own terminal, the frame header analyzing unit 3
In step 03, the transfer expiration date information in the frame is subtracted by 1, and then stored in the transfer expiration date control unit 701. The stored transfer expiration date information is notified to the transfer expiration date adding unit 702. Further, the frame header analysis unit 303
The retransmission control unit 310 is notified of the arrival of the retransmission request frame.

The retransmission control unit 310 notified of the arrival of the retransmission request frame extracts the frame number from the retransmission request frame, reads out the data frame of the corresponding frame number from the retransmission frame buffer 305, 702 is controlled.

The transfer expiration date adding unit 702 adds the transfer expiration date information notified from the transfer expiration date control unit 701 to the input retransmission request frame. The retransmission request frame to which the transfer expiration date information has been added is further added with an error detection code by the error detection code adding section 308, and is transmitted from the data transmitting section 309.

The transfer expiration date control unit 701 decrements the stored transfer expiration date information by one every time the transmission of one transmission frame elapses. Here, when the transfer expiration date information becomes less than 0, the transfer expiration date control unit 7
01 outputs a notice to that effect to retransmission control section 310.
Upon receiving the notification, retransmission control section 310 controls each section to cancel transmission of the transmission frame.

FIG. 8 is a diagram showing a transfer sequence in this embodiment. The first to third data links are:
It is assumed that wireless data transmission is performed in the same frequency band. The polling generated from the receiving transmission device is transferred in order from the second relay transmission device to the first relay transmission device, and reaches the transmission transmission device. Numbers in parentheses such as (1) in the figure represent frame numbers. The numbers in parentheses such as [1] in the figure indicate the transfer expiration date. This transfer expiration date is incremented by one every time one frame is relayed or transmitted.
Decrease by one.

First, the transmitting transmission device that has received the polling transmits a data frame having a frame number from 1 to 7 to the first relay transmission device. An x mark in the figure indicates that an error has occurred in the data frame.
The data Nos. 1 and 2 in which an error has occurred are discarded by the first relay transmission device.

The first relay transmission device stores the normally received third, fourth, fifth, sixth, and seventh data frames in the retransmission frame buffer and transmits the data frames to the second relay transmission device. Send. The second relay transmission device transmits the normally received fifth and seventh data frames to the reception transmission device while storing them in the retransmission frame buffer.

The receiving / transmitting apparatus stores the fifth and seventh data frames in the frame order reconstructing unit, and retransmits the missing first, second, third, fourth and sixth data frames. Generation of the requested retransmission request frame is instructed by the retransmission control unit. The generated retransmission request frame is
The data is transmitted to the second relay transmission device.

Since the second relay transmission apparatus does not store the first, second, third, fourth and sixth data frames in the retransmission frame buffer, the second relay transmission apparatus receives the received retransmission request frame as it is in the first transmission frame buffer. Send to relay transmission device. The first relay transmission device stores the third, fourth, and sixth data frames in the retransmission frame buffer.
No. 4, No. 6, and No. 6 data frames are stored in the relay buffer, and retransmission request frames requesting retransmission of No. 1 and No. 2 data frames are generated and transmitted to the transmission device.

The transmitting transmission apparatus receives the retransmission request and transmits the first and second data frames to the first relay transmission apparatus. The first relay transmission device stores the first and second data frames in the relay buffer while storing the first and second data frames in the retransmission frame buffer, and then stores the first and second data frames in combination with the third, fourth, and sixth data frames in the relay buffer. The second data frame and the second data frame are transmitted to the second relay transmission device. The second relay transmission apparatus transmits the normally received second data frame to the reception transmission apparatus while storing it in the retransmission frame buffer.

The receiving and transmitting apparatus stores the normally received second data frame in the frame order reconstruction unit. Furthermore, No. 1, No. 3, and No. 4 missing by the retransmission control unit
Generation of a retransmission request frame requesting retransmission of the No. 6 and No. 6 data frames is instructed, and the generated retransmission request frame is transmitted to the second relay transmission device.

Since the second, third, fourth, and sixth data frames are not stored in the retransmission frame buffer, the second relay transmission apparatus transmits the received retransmission request frame as it is to the first relay transmission apparatus. Send to device.

In the first relay transmission device, since the first, third, fourth and sixth data frames are stored in the retransmission frame buffer, the first, third, fourth and sixth data frames are stored. Store the frame in the relay buffer. Here, the data frame requested in the retransmission request frame is:
Since all retransmission frames exist in the retransmission frame buffer, the retransmission request frame is not sent to the transmission device. Then 1
The third, fourth, and sixth data frames are transmitted to the second relay transmission device.

The second relay transmission apparatus stores the first, third and sixth data frames received normally in the retransmission frame buffer while storing them in the relay buffer, and then stores the first data frame in the relay buffer. Is transmitted to the receiving and transmitting apparatus. Here, when the first frame in the relay buffer is transmitted to the receiving transmission device, the transfer expiration date of the second relay transmission device becomes less than 0. Therefore, transmission of subsequent data frames is cancelled. On the other hand, the receiving transmission device
Since the polling period has elapsed since the previous polling frame was transmitted, the next polling is transmitted.

As described above, according to the present embodiment, data transmission and error retransmission can be performed by sequentially passing the transmission frame transmission order for each transmission device. Further, even when the retransmission period is prolonged due to a transmission error, it becomes possible for each transmission device to know the next polling transmission. As a result, even when the transmission of a certain data link affects the transmission of another data link, such as a wireless transmission path, it is possible to perform data transfer by relay without collision.

In the present embodiment, the transfer expiration date information is an integer in units of the time required to transmit one transmission frame. However, the transfer expiration information may be real time, such as seconds. In such a case, the value to be subtracted when stored in the transfer expiration date control unit may be replaced with 1 and replaced with the actual time required to transmit one transmission frame.

Further, the data transmission system according to the present embodiment has been described assuming that the transmission path is a wireless transmission path. However, the data transmission system according to the present embodiment may use a wired transmission path connected in a bus form. Also in this case, the data transmission system according to the present embodiment can exert the same effect.

Further, in the data transmission system according to the present embodiment, a two-stage relay using two relay transmission devices has been described. However, the data transmission system according to the present embodiment can exert the same effect in M-stage relay (M is a natural number).

(Third Embodiment) FIGS. 9, 10 and 11 are diagrams showing the configuration of a data transmission system according to a third embodiment. The data transmission system according to the present embodiment includes a transmission path 41 that is a wireless transmission path, a reception transmission apparatus 61 that wirelessly receives and outputs data transmitted via the transmission path 41, and an input to the reception transmission apparatus 61. A transmission transmission device 71 for wirelessly transmitting data and a relay transmission device 51 installed between the reception transmission device 61 and the transmission transmission device 71 to extend the transmission distance are provided. Since the data transmission system according to the present embodiment is substantially the same as the configuration in the second embodiment, the description of the common configuration will be omitted, and the differences will be described below.

Referring to FIG. 9, the relay transmission device 51
Unlike the relay transmission device 50 of FIG.
And the data transmission unit 109 is not provided.
A radio receiving unit 901 that demodulates a transmission wave on the transmission line 41 to generate a transmission frame such as a data frame, a polling frame, and a retransmission request frame; and a radio transmission unit 902 that modulates a data frame and sends the data frame to the transmission line as a transmission wave. Is provided.

The radio receiving unit 901 and the radio transmitting unit 902 are typically included in a single radio modem 900, but if they cannot be transmitted and received simultaneously, they are not necessarily included in a single radio modem. That it does not need to be included is as described above.

Further, the relay transmission device 51
02 and an antenna control unit 9 that controls switching of a directional antenna based on information from the transfer expiration date adding unit 502
03, an antenna switching unit 904 that switches antennas under the control of the antenna control unit 903, and directional antennas 906 and 90 that transmit and receive radio only in a specific direction.
7 is further provided. Note that the antennas that receive the radio signals from the directional antennas 906 and 907 are the directional antennas 905 and 908, respectively.

Referring to FIG. 10, receiving / transmitting device 61
Is different from the receiving and transmitting apparatus 60 of FIG.
05 and a data transmission unit 204, and instead of these, a wireless reception unit 1002 that demodulates a transmission wave on the transmission path 41 and generates transmission frames such as a data frame, a polling frame, and a retransmission request frame; Radio transmission unit 10 that modulates and transmits the transmission wave on a transmission path
01.

The radio receiving unit 1002 and the radio transmitting unit 1001 are typically included in a single radio modem 1000. However, if the transmission and reception cannot be performed simultaneously, the radio reception unit 1002 and the radio transmission unit 1001 are not necessarily included in a single radio modem. That it does not need to be included is as described above.

Referring to FIG. 11, transmission transmission device 71
Is different from the transmission transmission device 70 of FIG.
01 and a data transmission unit 309. Instead of these, a wireless reception unit 1101 that demodulates a transmission wave on the transmission path 41 and generates transmission frames such as a data frame, a polling frame, and a retransmission request frame, and a data frame Radio transmission unit 11 that modulates and transmits the transmission wave on a transmission path
02.

Radio receiving section 1101 and radio transmitting section 1102 are typically included in a single wireless modem 1100. However, if they cannot be transmitted and received simultaneously, they are not necessarily included in a single wireless modem. That it does not need to be included is as described above.

Next, referring to FIG.
1 will be described. In the relay transmission device 51, the wireless reception unit 901 receives a transmission frame. The error detection unit 102 determines whether the received transmission frame is a normal frame. When an error is detected in a frame, the frame is discarded by the error detection unit 102. If no errors are detected,
The frame information of the frame is analyzed by the frame header analysis unit 103.

If it is determined that the frame is addressed to the own terminal, the frame header analysis unit 103 subtracts 1 from the transfer expiration date information in the frame, and stores it in the transfer expiration date control unit 501. . Further, the frame header analysis unit 103 notifies the relay control unit 104 of the type of the analyzed frame.

When the analyzed frame is notified that the frame is a polling frame, the relay control unit 104 sets the retransmission frame buffer 105 and the relay buffer 106
Clear Further, the relay control unit 104 controls the destination change unit 107 to rewrite the destination of the polling frame to the adjacent transmission device on the transmission side, and to transmit the polling frame to the transfer expiration date adding unit 502.

The transfer expiration date adding unit 502 adds the transfer expiration date information stored by the transfer expiration date control unit 501 to the polling frame. The polling frame to which the transfer expiration date information has been added is further added with an error detection code by the error detection code adding unit 108.
On the other hand, antenna control section 903 controls antenna switching section 904 so as to select an antenna in the direction in which the transmission device transmitting the frame exists. The antenna switching unit 904 is controlled by the antenna control unit 903.
Switch antennas. After that, the wireless transmission unit 902
Transmits the polling frame.

Note that the antenna control unit 903 receives the transfer expiration date information from the transfer expiration date adding unit 502,
There is a built-in timer that times out when the time indicated by the transfer expiration date information elapses. When the timer times out, the antenna control unit 903 controls the antenna switching unit 904 so that the transmission / reception antenna is returned to the reception transmission device side. Under the control of the antenna control unit 903, the antenna switching unit 904 switches the antenna.

If the analyzed frame is notified that the frame is a data frame, the relay control unit 104 causes the destination change unit 107 to rewrite the destination of the data frame to the transmission device adjacent to the receiving side, and The frames are stored in the relay buffer 106 while being accumulated in the retransmission frame buffer 105.

Further, when the relay control unit 104 detects the end of the reception of a series of data frames, the relay control unit 104 controls the data frame stored in the relay buffer 106 to be transmitted to the transfer expiration date adding unit 502, and At the end of the process, the relay buffer 106 is cleared.

The transfer expiration date adding unit 502 is a transfer expiration date control unit 501 which is decremented by one for each data frame.
Is added to the corresponding data frame. The data frame to which the transfer expiration date information is added is output by the error detection code adding unit 108.
An error detection code is further added. On the other hand, antenna control section 903 controls antenna switching section 904 so as to select an antenna in the direction in which the transmission device transmitting the frame exists. Under the control of the antenna control unit 903, the antenna switching unit 904 switches the antenna. After that, the wireless transmission unit 902 transmits the data frame.

Note that the antenna control unit 903 has a built-in timer that times out when the transfer expiration time has elapsed, as described above. When the timer times out, the antenna control unit 903 controls the antenna switching unit 904 so that the transmission / reception antenna is returned to the reception transmission device side. Under the control, the antenna switching unit 90
4 switches the antenna.

If the analyzed frame is notified that the frame is a retransmission request frame, the relay control unit 104 clears the relay buffer 106, and the data frame requested to be retransmitted exists in the retransmission frame buffer 105. To determine whether the existing data frame exists in the relay buffer 1 or not.
06.

Further, relay control section 104 notifies retransmission request frame reconstructing section 110 of the frame number existing in retransmission frame buffer 105. Relay control unit 10
4 is based on the retransmission request frame input from the frame header analysis unit 103 to the retransmission request frame reconfiguration unit 110,
Retransmission request frame reconstructing section 110 so as to remove the frame number existing in retransmission frame buffer 105
Control. The frame is input to the destination changing unit 107. The relay control unit 104 changes the frame to the destination of the transmission device on the transmission side by the destination change unit 107,
Control is performed so as to be input to the transfer expiration date adding unit 502.

Transfer expiration date adding section 502 responds to the input retransmission request frame by a transfer expiration date control section 501.
The transfer expiration date information notified by the notification is added. The retransmission request frame to which the transfer expiration date information has been added is further added with an error detection code by the error detection code adding unit 108. On the other hand, antenna control section 903 controls antenna switching section 904 so as to select an antenna in the direction in which the transmission device transmitting the frame exists. Upon receiving the control, the antenna switching unit 904 switches the antenna. Thereafter, wireless transmission section 902 transmits the retransmission request frame.

Note that the antenna control unit 903 has a built-in timer that times out when the transfer expiration time elapses, as described above. When the timer times out, the antenna control unit 903 controls the antenna switching unit 904 so that the transmission / reception antenna is returned to the reception transmission device side. Under the control, the antenna switching unit 90
4 switches the antenna.

The transfer expiration date control unit 501 decrements the stored transfer expiration date by one each time the time for transmitting one transmission frame elapses. Here, when the transfer expiration date becomes less than 0, the transfer expiration date control unit 501
Outputs a notification to that effect to the relay control unit 104. The relay control unit 104 that has received the notification controls each unit so as to cancel the transmission of the transmission frame.

Next, the operation of the receiving and transmitting apparatus 61 will be described with reference to FIG. In the reception transmission device 61, the polling cycle counting unit 201
It instructs the polling frame generation unit 202 to issue a polling transmission command. Further, the polling cycle counting unit 201 stores the value of the quotient obtained by dividing the polling cycle by the time required for transmitting one transmission frame as transfer expiration date information in the transfer expiration date control unit 601.

Upon receiving the polling transmission command, polling frame generation section 202 generates a polling frame addressed to an adjacent relay transmission apparatus and sends it to transfer expiration date adding section 602. The transfer expiration date adding unit 602 adds the transfer expiration date information notified by the transfer expiration date control unit 601 to the polling frame. The polling frame to which the transfer expiration date information has been added is further added with an error detection code by the error detection code adding section 203 and transmitted from the wireless transmission section 1001.

Radio receiving section 1002 receives a transmission frame. The error detection unit 206 determines whether the transmission frame received by the wireless reception unit 1002 is a normal frame. If an error is detected in the frame, the error detection unit 206 discards the frame. If no error is detected, the frame information of the frame is analyzed by the frame header analysis unit 207.

When the frame is analyzed as a data frame addressed to the terminal itself, the frame header analysis unit 207 subtracts the transfer expiration date information in the frame by 1, and stores it in the transfer expiration date control unit 601. Further, the frame header analysis unit 207 notifies the retransmission control unit 209 of the arrival of the frame, and stores the frame in the frame order reconfiguration unit 208.

After a series of data is received, retransmission control section 209 detects an unarrived data frame in the received data. When there is no unarrived data frame, the retransmission control unit 209 controls the data to be output from the frame order reconfiguration unit 208 in order according to the frame number, and uses the output data as a received data output. .

If there is an unarrived data frame, the retransmission control unit 209 sends the retransmission request frame generation unit 210 a retransmission request that stores the frame number of the unarrived data frame to the adjacent relay transmission device. Control is performed such that a request frame is created and input to the transfer expiration date adding unit 602.

The transfer expiration date adding unit 602 adds the transfer expiration date information stored in the transfer expiration date control unit 601 to the retransmission request frame. The retransmission request frame to which the transfer expiration date information has been added is further added with an error detection code by the error detection
Sent from 01.

The transfer expiration date control unit 601 decrements the stored transfer expiration date by one each time the time for transmitting one transmission frame elapses. Here, the transfer expiration date is 0
If it is less than, the transfer expiration date control unit 601
A notification to that effect is output to retransmission control section 209. Upon receiving the notification, the retransmission control unit 209 controls each unit so as to cancel transmission of the transmission frame.

Next, the operation of the transmission device 71 will be described with reference to FIG. In the transmission transmission device 71, the wireless reception unit 1101 receives a transmission frame.
The error detection unit 302 determines whether the received transmission frame is a normal frame. If an error is detected in the frame, the frame is discarded by the error detection unit 302. If no error is detected, the frame information of the frame is analyzed by the frame header analysis unit 303.

When the analyzed frame is determined to be a polling frame addressed to the own terminal, the frame header analysis unit 303 subtracts 1 from the transfer expiration date information in the frame, and then sends it to the transfer expiration date control unit 701. Store. Further, the frame header analysis unit 303 notifies the transmission control unit 304 of the arrival of the polling frame.

After being notified of the arrival of the polling frame, the transmission control unit 304 clears the retransmission frame buffer 305 and then transmits the specified number of frames to the transmission data buffer 30.
Data is read from 6. The read data is framed by the data frame generation unit 307 by adding a frame number to an adjacent relay transmission device in order. The transmission control unit 304 sends the framed data to the transfer expiration date adding unit 702 while storing the framed data in the retransmission frame buffer 305.

The transfer expiration date adding unit 702 adds the transfer expiration date information stored in the transfer expiration date control unit 701 to the data frame. The data frame to which the transfer expiration date information has been added is processed by the error detection code adding unit 308.
An error detection code is further added to the radio transmission unit 1102
Sent by

If the analyzed frame is determined to be a retransmission request frame addressed to the own terminal, the frame header analyzing unit 3
In step 03, the transfer expiration date information in the frame is subtracted by 1, and then stored in the transfer expiration date control unit 701. Further, frame header analysis section 303 notifies retransmission control section 310 of the arrival of the retransmission request frame.

Upon receiving the notification of the arrival of the retransmission request frame, retransmission control section 310 extracts the frame number from the retransmission request frame, reads out the data frame of the corresponding frame number from retransmission frame buffer 305, and transfers the data to the expiration date adding section. 702 is controlled.

The transfer expiration date adding unit 702 adds the transfer expiration date information stored in the transfer expiration date control unit 701 to the input data frame. The data frame to which the transfer expiration date information is added is sent to the error detection code adding unit 308.
Thus, an error detection code is further added and transmitted from wireless transmission section 1102.

The transfer expiration date control unit 701 decrements the stored transfer expiration date by one each time the transmission of one transmission frame elapses. Here, the transfer expiration date is 0
If the number is less than the transfer expiration date control unit 701,
A notification to that effect is output to retransmission control section 310. Upon receiving the notification, retransmission control section 310 controls each section to cancel transmission of the transmission frame.

FIG. 12 is a diagram showing a transfer sequence in the present embodiment. It is assumed that the first to third data links each perform wireless data transmission in the same frequency band. In the initial state, the transmitting and receiving antennas of the first and second relay transmission devices are respectively directed to the receiving transmission device side. Numbers in parentheses such as (1) in the figure represent frame numbers. The numbers in parentheses such as [1] in the figure indicate the transfer expiration date. This transfer expiration date is reduced by 1 each time relaying or transmission of one frame is performed.

In FIG. 12, the polling generated from the receiving transmission device is transferred from the second relay transmission device to the first relay transmission device in order, and reaches the transmission transmission device. First
When the polling frame is received by the second relay transmission device, the antenna control unit provided in each of the devices times out when the transfer expiration time elapses based on the transfer expiration information included in the polling frame. The timers Ta1 and Ta2 are started, respectively. When the reception is completed, the antenna control units provided in the first and second relay transmission devices switch the directional antenna to the antenna on the transmission transmission device side of the transmission destination. Switching times are indicated as A and C in the figure. Further, by switching the transmission / reception direction as described above and further maintaining the state, the first and second relay transmission apparatuses can be prepared for a possibility that a data frame is transmitted from the transmission transmission apparatus side. it can.

The transmission transmitting apparatus that has received the polling is 1
A data frame having a frame number from No. 7 to No. 7 is transmitted to the first relay transmission device. The crosses in the figure are
Indicates that an error has occurred in the data frame. The frame in which the error has occurred is discarded by the first relay transmission device.

The first relay transmission device stores the normally received third, fourth, fifth, sixth, and seventh data frames in the retransmission frame buffer and transmits the data frames to the second relay transmission device. Send. At this time, in the antenna control unit provided in the device, the timer Ta1 is reset, and the transmitting and receiving antenna is returned to the receiving and transmitting device. The point in time is indicated as D in the figure. It should be noted that the timer Ta1 may not be reset, and the value may be overwritten when new transfer expiration date information is input.

Next, the 3 transmitted from the first relay transmission device
No. 4, No. 5, No. 6, No. 7 and all No. 7 data frames have errors. Therefore, these data
Discarded by the second relay transmission device. In the second relay transmission device, since there is no normally received data frame, when the timer Ta2 times out, the transmission / reception antenna is returned to the reception transmission device side. At that time, B in the figure
It is shown as

As described above, in the data transmission system according to the present embodiment, even when the transmission of a frame is completely interrupted due to an error on the transmission path, etc.
By using the timer described in the above, the transmitting and receiving antennas can be accurately controlled. Typically, at the time of the next polling, the transmission / reception antenna of each relay transmission device is always returned to the reception transmission device side, so that the polling frame can be reliably received.

[0187] The data transmission system according to the present embodiment is configured such that a plurality of directional antennas 906 and 907 are switched by an antenna switching unit 904 to control transmission and reception antennas. However, only one directional antenna may be provided, and the antenna control unit 903 may control such that the directivity of the antenna changes. Typically, the antenna control unit 903 may control the antenna to rotate so that the directivity changes. Further, an adaptive array antenna may be used as a transmission / reception antenna, and the antenna control unit 903 may change the signal weighting value from each antenna element to control the directivity.

Further, in the present embodiment, the transfer expiration date information is an integer in units of the time required to transmit one transmission frame. However, the transfer expiration information may be real time, such as seconds. In such a case, the value to be subtracted when the data is stored in the transfer expiration date control unit may be replaced with 1 and replaced with the time required to transmit one transmission frame.

Furthermore, the data transmission system according to the present embodiment has been described for the two-stage relay using two relay transmission devices. However, the data transmission system according to the present embodiment can exert the same effect in M-stage relay (M is a natural number).

(Fourth Embodiment) FIG. 13 is a diagram showing a configuration of a data transmission system according to a fourth embodiment. The data transmission system according to the present embodiment includes a transmission path 41 that is a wireless transmission path, a reception transmission apparatus 61 that wirelessly receives and outputs data transmitted via the transmission path 41,
A transmission transmission device 71 for wirelessly transmitting input data to the reception transmission device 61, and a relay transmission device 52 installed between the reception transmission device 61 and the transmission transmission device 71 to extend the transmission distance are provided. Since the data transmission system according to the present embodiment is substantially the same as the configuration in the third embodiment, description of the common configuration will be omitted, and differences will be described below.

Referring to FIG. 13, relay transmission device 52
Is different from the relay transmission device 51 of FIG. 9 in that the radio reception unit 14 is capable of switching to one of a plurality of frequency channels.
01 and a wireless transmission unit 1402. Note that the wireless receiving unit 1401 and the wireless transmitting unit 1402 are typically included in a single wireless modem 1400, but if they cannot be transmitted and received simultaneously, they need not necessarily be included in a single wireless modem. The absence of is as described above. Further, the relay transmission device 52 includes a wireless transmission unit 1402
And a frequency channel control section 1403 for controlling switching of frequency channels based on information from the transfer expiration date adding section 502. Note that the configuration of the reception transmission device 61 is the same as that of FIG. 10, and the configuration of the transmission transmission device 71 is the same as that of FIG.

Next, the operation of the relay transmission device 52 will be described with reference to FIG. In the relay transmission device 52, the wireless reception unit 1401 receives a transmission frame.
The error detection unit 102 determines whether the received transmission frame is a normal frame. When an error is detected in a frame, the frame is discarded by the error detection unit 102. If no error is detected, the frame information of the frame is analyzed by the frame header analysis unit 103.

When it is determined that the frame is addressed to the own terminal, the frame header analysis unit 103 subtracts 1 from the transfer expiration date information in the frame, and stores it in the transfer expiration date control unit 501. . Further, the frame header analysis unit 103 notifies the relay control unit 104 of the type of the analyzed frame.

When the analyzed frame is notified that the frame is a polling frame, the relay control unit 104 sets the retransmission frame buffer 105 and the relay buffer 106
Clear Further, the relay control unit 104 controls the destination change unit 107 to rewrite the destination of the polling frame to the adjacent transmission device on the transmission side, and to transmit the polling frame to the transfer expiration date adding unit 502.

The transfer expiration date adding unit 502 adds the transfer expiration date information stored by the transfer expiration date control unit 501 to the polling frame. The data frame to which the transfer expiration date information is added is sent to the error detection code adding unit 1.
08, an error detection code is further added. On the other hand, the frequency channel control unit 1403 controls the radio reception unit 1401 and the radio transmission unit 14 so as to switch to the frequency channel used for communication with the adjacent transmission device on the transmission side.
Set 02. After that, the wireless transmission unit 1402 transmits the polling frame.

Note that frequency channel control section 1403
When a transfer expiration date information is input from the transfer expiration date addition unit 502 and a time indicated by the transfer expiration date information elapses, a timer that times out is built in. When the timer times out, the frequency channel control unit 1403
Is set to return the radio receiving unit 1401 and the radio transmitting unit 1402 to the frequency channel used for communication with the receiving and transmitting apparatus.

When the analyzed frame is notified that the frame is a data frame, the relay control unit 104 causes the destination change unit 107 to rewrite the destination of the data frame to a transmission device adjacent to the receiving side, and retransmits the data frame. The data frame is stored in the relay buffer 106 while the data frame is stored in the frame buffer 105 for use.

Further, when the relay control unit 104 detects the end of reception of a series of data frames, the relay control unit 104 controls the data frame stored in the relay buffer 106 to be transmitted to the transfer expiration date adding unit 502, and At the end of the process, the relay buffer 106 is cleared.

The transfer expiration date adding unit 502 is a transfer expiration date control unit 501 that is decremented by one for each data frame.
Is added to the corresponding data frame. The data frame to which the transfer expiration date information is added is output by the error detection code adding unit 108.
An error detection code is further added. On the other hand, frequency channel control section 1403 sets radio reception section 1401 and radio transmission section 1402 such that a frequency channel used for communication with the transmission apparatus transmitting the frame is selected. Thereafter, wireless transmission section 1402 transmits the data frame.

[0200] Frequency channel control section 1403
As described above, a timer is provided which times out when the transfer expiration time elapses. When the timer times out, frequency channel control section 1403 sets wireless receiving section 1401 and wireless transmitting section 1402 to return to the frequency channel used for communication with the receiving and transmitting apparatus.

If the analyzed frame is notified that the frame is a retransmission request frame, the relay control unit 104 clears the relay buffer 106, and the data frame requested to be retransmitted exists in the retransmission frame buffer 105. To determine whether the existing data frame exists in the relay buffer 1 or not.
06.

Further, relay control section 104 notifies retransmission request frame reconstructing section 110 of the frame number existing in retransmission frame buffer 105. Relay control unit 10
4 is based on the retransmission request frame input from the frame header analysis unit 103 to the retransmission request frame reconfiguration unit 110,
Retransmission request frame reconstructing section 110 so as to remove the frame number existing in retransmission frame buffer 105
Control. The frame is input to the destination changing unit 107. The relay control unit 104 changes the frame to the destination of the transmission device on the transmission side by the destination change unit 107,
Control is performed so as to be input to the transfer expiration date adding unit 502.

[0203] The transfer expiration date adding section 502 responds to the input retransmission request frame by a transfer expiration date control section 501.
The transfer expiration date information notified by the notification is added. The retransmission request frame to which the transfer expiration date information has been added is further added with an error detection code by the error detection code adding unit 108. On the other hand, frequency channel control section 1403 sets radio reception section 1401 and radio transmission section 1402 such that a frequency channel used for communication with the transmission apparatus transmitting the frame is selected. Then, the wireless transmission unit 1
402 transmits the retransmission request frame.

The frequency channel control section 1403
As described above, a timer is provided which times out when the transfer expiration time elapses. When the timer times out, frequency channel control section 1403 sets wireless receiving section 1401 and wireless transmitting section 1402 to return to the frequency channel used for communication with the receiving and transmitting apparatus.

The transfer expiration date control unit 501 decrements the stored transfer expiration date by one each time the time for transmitting one transmission frame elapses. Here, when the transfer expiration date becomes less than 0, the transfer expiration date control unit 501
Outputs a notification to that effect to the relay control unit 104. The relay control unit 104 that has received the notification controls each unit so as to cancel the transmission of the transmission frame.

The operations of the reception transmission device 61 and the transmission transmission device 71 are the same as the operations in the third embodiment, and the description is omitted.

FIG. 14 is a diagram showing a transfer sequence in the present embodiment. In FIG. 14, the first data link is channel 1, the second data link is channel 2,
It is assumed that the third data link performs wireless data transmission in each frequency band of channel 3. The use of different frequency bands in each data link in this manner does not typically overlap with the frequency band of jamming waves radiated from a radio wave source (eg, a microwave oven) that hinders wireless data transmission. That's why.

For example, it is assumed that a radio wave generating source that emits an interfering radio wave in the same frequency band as channel 3 exists around the first relay transmission device. In such a case, it is difficult for the first relay transmission device to use the channel 3 when receiving a radio wave transmitted from the second relay transmission device or the transmission transmission device. This is because radio waves transmitted from distant transmission devices are weak, and radio waves generated by nearby radio wave sources are strong, so that there is a high possibility that reception will be hindered. Similarly, channel 1 is located around the second relay transmission device.
If there is a radio wave generation source that emits an interfering radio wave in the same frequency band as above, the second relay transmission apparatus receives a radio wave transmitted from the first relay transmission apparatus or the reception transmission apparatus. 1 becomes difficult to use. Therefore, in such a case, if the frequency channel of each data link is set as shown in FIG. 14, a signal from each transmission device can be satisfactorily received without being disturbed by interference waves from each radio wave generation source. be able to.

In FIG. 14, it is assumed that the transmission / reception channel of the first relay transmission device is set to channel 2 and the transmission / reception channel of the second relay transmission device is set to channel 3 in the initial state. Further, the numbers in parentheses such as (1) in the figure represent frame numbers. The numbers in parentheses such as [1] in the figure indicate the transfer expiration date. This transfer expiration date is reduced by 1 each time relaying or transmission of one frame is performed.

In FIG. 14, the polling generated from the reception transmission device is transferred from the second relay transmission device to the first relay transmission device in order, and reaches the transmission transmission device. First
And the second relay transmission device, upon receiving the polling frame, causes the frequency channel control unit provided in each of the devices to time out when the transfer expiration time elapses based on the transfer expiration information included in the polling frame. Activate timers Ta1 and Ta2, respectively.

When the reception is completed, the frequency channel control unit of the first relay transmission apparatus sets the transmission / reception channel to channel 1
, And the frequency channel control unit of the second relay transmission apparatus switches the transmission / reception channel to channel 2. Switching times are indicated as A and C in the figure.
Further, by switching the transmission / reception channel as described above and further maintaining the state, the first and second relay transmission apparatuses can be prepared for a possibility that a data frame is transmitted from the transmission transmission apparatus side. it can.

[0212] The transmitting transmission apparatus that has received the polling is 1
A data frame having a frame number from No. 7 to No. 7 is transmitted to the first relay transmission device. The crosses in the figure are
Indicates that an error has occurred in the data frame. The frame in which the error has occurred is discarded by the first relay transmission device.

The first relay transmission apparatus stores the normally received third, fourth, fifth, sixth, and seventh data frames in the retransmission frame buffer and transmits the data frames to the second relay transmission apparatus. Send. At this time, the timer Ta1 is reset in the frequency channel control unit provided in the device, and the transmission / reception channel is returned to channel 2. The point in time is indicated as D in the figure. It should be noted that the timer Ta1 may not be reset, and the value may be overwritten when new transfer expiration date information is input.

Next, the 3 transmitted from the first relay transmission device
No. 4, No. 5, No. 6, No. 7 and all No. 7 data frames have errors. Therefore, these data
Discarded by the second relay transmission device. The second relay transmission device returns the transmission / reception channel to channel 3 when the timer Ta2 times out, because there is no data frame received normally. The point in time is shown as B in the figure.

As described above, the data transmission system according to the present embodiment uses the above-described timer in the frequency channel control section 1403 even when the transmission of a frame is completely interrupted due to an error on the transmission path or the like. ,
Transmission and reception channels can be controlled accurately. Typically, at the time of the next polling, the transmission / reception channel of each relay transmission device is always returned to the channel used for communication with the transmission device on the reception transmission device side. Can be.

In the above description, a case has been described by way of example in which radio reception section 1401 and radio transmission section 1402 are included in a single radio modem 1400 and the transmission and reception channels are simultaneously switched. However, the wireless receiving unit 1401 and the wireless transmitting unit 1402 do not necessarily need to be included in a single wireless modem as long as they cannot transmit and receive at the same time. Therefore, in such a case, switching of the transmission channel may be performed during reception, for example, and switching of the reception channel may be performed during transmission. However, when the timer times out using the timer described above, it is necessary that the receiving channel of each relay transmission device is always returned to the channel used for communication with the transmission device on the receiving transmission device side. Then, the polling frame can be reliably received as described above.

In this embodiment, the transfer expiration date information is an integer in units of the time required to transmit one transmission frame. However, the transfer expiration information may be real time, such as seconds. In such a case, the value to be subtracted when the data is stored in the transfer expiration date control unit may be replaced with 1 and replaced with the time required to transmit one transmission frame.

Furthermore, the data transmission system according to the present embodiment has been described for the two-stage relay using two relay transmission devices. However, the data transmission system according to the present embodiment can exert the same effect in M-stage relay (M is a natural number).

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a relay transmission device using a relay transmission method according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a reception transmission device using the relay transmission method according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a transmission apparatus using the relay transmission method according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a sequence of a relay transmission method according to the first embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a relay transmission device using a relay transmission method according to a second embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a reception transmission device using a relay transmission method according to a second embodiment of the present invention.

FIG. 7 is a block diagram illustrating a configuration of a transmission device using a relay transmission method according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a sequence of a relay transmission method according to the second embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of a relay transmission device using a relay transmission method according to a third embodiment of the present invention.

FIG. 10 is a block diagram illustrating a configuration of a reception transmission apparatus using a relay transmission method according to a third embodiment of the present invention.

FIG. 11 is a block diagram showing a configuration of a transmission device using a relay transmission method according to a third embodiment of the present invention.

FIG. 12 is a diagram showing a sequence of a relay transmission method according to a third embodiment of the present invention.

FIG. 13 is a block diagram showing a configuration of a relay transmission device using a relay transmission method according to a fourth embodiment of the present invention.

FIG. 14 is a diagram showing a sequence of a relay transmission method according to a fourth embodiment of the present invention.

FIG. 15 is a block diagram showing a configuration of a conventional relay transmission system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 relay transmission device 20 reception transmission device 30 transmission transmission device 40, 41 transmission line 50-52 relay transmission device 60, 61 reception transmission device 70, 71 transmission transmission device 100 modem 101 data reception unit 102 error detection unit 103 frame header analysis unit Reference Signs List 104 relay control unit 105 retransmission frame buffer 106 relay buffer 107 destination change unit 108 error detection code addition unit 109 data transmission unit 110 retransmission request frame reconfiguration unit 200 modem 201 polling cycle counting unit 202 polling frame generation unit 203 error detection code addition Unit 204 data transmission unit 205 data reception unit 206 error detection unit 207 frame header analysis unit 208 frame order reconstruction unit 209 retransmission control unit 210 retransmission request frame generation unit 300 modem 301 data reception unit 3 2 Error detection unit 303 Frame header analysis unit 304 Transmission control unit 305 Retransmission frame buffer 306 Transmission data buffer 307 Data frame generation unit 308 Error detection code addition unit 309 Data transmission unit 310 Retransmission control unit 501 Transfer expiration time control unit 502 Transfer effective Expiration date addition unit 601 Transfer expiration date control unit 602 Transfer expiration date addition unit 701 Transfer expiration date control unit 702 Transfer expiration date addition unit 900 Wireless modem 901 Radio reception unit 902 Radio transmission unit 903 Antenna control unit 904 Antenna switching unit 905-908 Direction Antenna 1000 Wireless modem 1001 Wireless transmitter 1002 Wireless receiver 1100 Wireless modem 1101 Wireless receiver 1102 Wireless transmitter 1400 Wireless modem 1401 Wireless transmitter 1402 Wireless receiver 1403 Wavenumber channel control unit

Claims (28)

[Claims] 1. A method of relaying and transmitting a data frame by performing transmission and reception at mutually different times, and sequentially transferring the data frame from a transmission transmission device to a reception transmission device via one or more relay transmission devices, A data transmission step in which the transmission transmission apparatus transmits the plurality of data frames to which the frame numbers are added to the reception transmission apparatus; a data transmission step in which one or more relay transmission apparatuses sequentially transfer the data frames; A retransmission request transmitting step of combining a frame number of the data frame that the reception transmission apparatus has not been able to normally receive into one retransmission request and transmitting the retransmission request to the transmission transmission apparatus; A retransmission request transferring step of sequentially transmitting the one or more data in response to the retransmission request. A relay transmission method, comprising: a data retransmission step of collectively retransmitting frames to the reception transmission apparatus; and a retransmission data transfer step of sequentially transmitting the data frames received by one or more of the relay transmission apparatuses. . 2. The data transfer step, wherein one or more of the relay transmission devices stores a normally received data frame among the data frames in a buffer of each relay transmission device. Transferring the data frames sequentially, wherein the retransmission request transfer step stores, in a buffer of the relay transmission device, a frame number included in the retransmission request received by one or more of the relay transmission devices. Deleting the frame number of the data frame stored in the buffer, and sequentially transferring the retransmission request from which the frame number of the data frame stored in the buffer has been deleted, wherein the retransmission data transfer step includes: For each data frame received by one or more of the relay transmission devices, 2. The method according to claim 1, further comprising: if a data frame stored in a buffer of the relay transmission device is present, adding the data frame; and further sequentially transferring the data frame to which the data frame is added. Relay transmission method. 3. The retransmission request transfer step, wherein all frame numbers included in the retransmission request received by the relay transmission device are included in frame numbers of data frames stored in a buffer of the relay transmission device. Judging whether or not it is included, if it is determined that the data frame is included, one or more data frames are collectively retransmitted to the receiving and transmitting apparatus in response to the retransmission request, and it is determined that the data frame is not included. 3. The method according to claim 2, further comprising the step of: deleting, from the frame number included in the retransmission request, the frame number of the data frame stored in the buffer of the relay transmission device, and sequentially transferring the data frame. Relay transmission method. 4. The relay transmission device has one or more directional antennas, and a predetermined transmission / reception direction is initially set. The data transmission step, the retransmission request transmission step, and the retransmission data transmission step A predetermined reception direction duration T when the relay transmission device receives a signal.
a) setting the transmission / reception direction by the relay transmission apparatus toward the transmission apparatus of the transmission destination; and elapse of the reception direction duration Ta. Resetting the transmission / reception direction. 5. The relay transmission method according to claim 4, wherein a plurality of said directional antennas are provided, and said transmission / reception direction is set by switching said plurality of directional antennas. 6. The relay transmission apparatus, wherein a predetermined frequency channel among a plurality of transmission / reception frequency channels is initially set, and wherein the data transfer step, the retransmission request transfer step, and the retransmission data transfer step include: Setting a predetermined reception channel duration Ta at the time of reception by the transmission device; setting the transmission / reception frequency channel for the relay transmission device to communicate with the transmission device of the transmission destination; and the reception channel duration Ta. 2. The relay transmission method according to claim 1, further comprising the step of: resetting the relay transmission apparatus to a predetermined frequency channel that has been initialized according to progress of the transmission. 7. The setting of the transmission / reception frequency channel includes:
7. The relay transmission method according to claim 6, wherein the transmission is performed by selecting a frequency channel that maximizes a throughput with a transmission apparatus of a transmission destination from among a plurality of transmission and reception frequency channels. 8. The data frame and the retransmission request are further added with transfer expiration date information indicating a predetermined time until the transfer is canceled, and the data transmission step includes a transmission required time per one data frame. Calculating the remaining time until the transfer is canceled for each data frame by sequentially subtracting the remaining time from the predetermined time until the transfer is canceled, and the remaining time calculated for each of the data frames. Adding it as new transfer expiration date information, the data transfer step, the retransmission request transmission step,
In the retransmission request transfer step, the data retransmission step, and the retransmission data transfer step, the required time from reception to transmission is sequentially subtracted from transfer expiration information included in the data frame or the retransmission request. By calculating the remaining time until the transfer is canceled, adding the calculated remaining time as new transfer expiration information, and when the new transfer expiration information becomes negative, 2. The relay transmission method according to claim 1, further comprising: stopping transmission or transfer. 9. The relay transmission method according to claim 8, wherein the transfer expiration date information is a natural number N where a time required for transmitting one frame is 1. 10. The relay transmission device has one or more directional antennas, a predetermined transmission / reception direction is initially set, and the data transfer step, the retransmission request transfer step, and the retransmission data transfer step Setting a predetermined receiving direction duration Ta by the relay transmission device using the received transfer expiration information; and setting the transmission / reception direction toward the transmission device by the relay transmission device. The relay transmission method according to claim 8, further comprising the step of resetting the relay transmission device to the initially set predetermined transmission / reception direction according to the elapse of the reception direction duration Ta. 11. The relay transmission device, wherein a predetermined frequency channel among a plurality of transmission / reception frequency channels is initially set, and wherein the data transfer step, the retransmission request transfer step, and the retransmission data transfer step include the step of: Setting a predetermined reception channel duration Ta at the time of reception by the transmission device; setting the transmission / reception frequency channel for the relay transmission device to communicate with the transmission device of the transmission destination; and the reception channel duration Ta. 9. The relay transmission method according to claim 8, further comprising the step of: resetting the relay transmission device to a predetermined frequency channel that has been initialized according to the elapse of. 12. The retransmission request transmitting step includes: comparing a predetermined time until the transmission transmission apparatus starts the next transmission with a maximum time required for retransmitting data according to the retransmission request; When the predetermined time until the data transmission is started is shorter, the retransmission request is not performed, and when the predetermined time is longer or the same, the reception / transmission apparatus cannot normally receive. 2. The relay transmission method according to claim 1, further comprising: combining the frame number of the data frame into one retransmission request and transmitting the retransmission request to the transmission transmission device. 13. The maximum time required for retransmitting data in response to the retransmission request is obtained by adding 1 to the number of retransmission frames, and adding the number of transfers and the time required to transmit one frame to the added value. And multiply the multiplied value by α (however,
13. The relay transmission method according to claim 12, wherein α is a value obtained by adding a predetermined numerical value determined by a processing capability. 14. A system for relaying and transmitting a data frame by performing transmission and reception at different times from each other and sequentially transferring the data frame from a transmission transmission device to a reception transmission device via one or more relay transmission devices, A transmitting unit that receives a retransmission request including a frame number of a data frame that the receiving transmission device has not normally received; a frame header analysis that extracts a frame number from the retransmission request received by the receiving unit; A data frame generation unit that generates a transmission data frame by adding a frame number to transmission data; and a transmission unit that transmits the transmission data frame. A receiving unit for receiving, a frame for extracting a frame number from a data frame received by the receiving unit; A header analysis unit, a retransmission request frame generation unit that generates a retransmission request including a frame number of a data frame that the reception transmission device has not been able to receive normally, and a transmission unit that transmits the retransmission request. The apparatus includes: a receiving unit that receives the data frame or the retransmission request; and a transmitting unit that transmits the data frame or the retransmission request received by the receiving unit. If the receiving transmission device has not received all of the data frames, the retransmission request is transmitted by the receiving transmission device, the transmission transmission device in response to the retransmission request,
A relay transmission system, wherein one or more data frames are collectively retransmitted to the reception transmission device. 15. The relay transmission device stores a normally received data frame, and when the transmission transmission device retransmits the data frame, further stores the data frame further stored for the data frame. A retransmission frame buffer for adding a transmission data frame, and a retransmission request frame for deleting a frame number of the data frame stored in the retransmission frame buffer from a frame number included in the received retransmission request. The relay transmission system according to claim 14, further comprising a reconfiguration unit. 16. The relay transmission apparatus may further comprise: one or more directional antennas for transmitting / receiving a signal; and a direction for transmitting / receiving a signal by controlling the directional antenna, and a predetermined reception direction duration Ta elapses. The relay transmission system according to claim 14, further comprising: an antenna control unit that resets the transmission direction to a predetermined transmission / reception direction that has been initially set. 17. The relay transmission device, comprising: a plurality of directional antennas for transmitting and receiving signals; an antenna switching unit for selectively switching between the plurality of directional antennas; and transmitting and receiving signals by controlling the antenna switching unit. 15. The relay transmission system according to claim 14, further comprising: an antenna control unit that sets the transmission direction to a predetermined direction and resets the transmission direction to an initially set predetermined transmission / reception direction when a predetermined reception direction duration Ta elapses. 18. The relay transmission apparatus sets a frequency channel for transmitting / receiving a signal among a plurality of transmission / reception frequency channels, and returns to an initially set predetermined frequency channel when a predetermined frequency channel duration Ta elapses. The relay according to claim 14, further comprising a frequency channel control unit configured to set, wherein the transmission unit and the reception unit transmit and receive a signal using a frequency channel set by the frequency channel control unit. Transmission system. 19. The transmission transmission apparatus according to claim 1, wherein the transmission required time for each data frame is sequentially subtracted from transfer expiration date information indicating a predetermined time until the transfer is cancelled. A transfer expiration date control unit that calculates the remaining time until the transfer is canceled and sets it as new transfer expiration date information, and controls the transmission to stop if the new transfer expiration date information becomes negative; A transfer expiration date adding unit that adds the transfer expiration date information to the data frame, wherein the reception transmission device sequentially subtracts a time required from reception to transmission from the transfer expiration date information included in the data frame. By doing so, the remaining time until the transfer is canceled is calculated and used as new transfer expiration date information, and the transfer expiration date information becomes negative. And a transfer expiration date control unit that controls transmission to be stopped if the transmission expiration date is reached, and a transfer expiration date addition unit that adds the transfer expiration date information to the retransmission request. By sequentially subtracting the time required for transmission from the transfer expiration information included in the data frame or the retransmission request, the remaining time before canceling the transfer is calculated as new transfer expiration information, A transfer expiration date control unit that controls to stop transmission when the transfer expiration date information becomes negative, and a transfer expiration date adding unit that adds the transfer expiration date information to the data frame or the retransmission request. The relay transmission system according to claim 14, further comprising: 20. The relay transmission system according to claim 19, wherein the transfer expiration date information is a natural number N where a time required for transmitting one frame is 1. 21. The relay transmission apparatus, comprising: one or more directional antennas for transmitting / receiving a signal; and setting the direction of transmitting / receiving a signal by controlling the directional antenna; The antenna control unit according to claim 19, further comprising: an antenna control unit configured to set a predetermined reception direction duration Ta by using, and to reset the initially set predetermined transmission / reception direction when the reception direction duration Ta elapses. Relay transmission system. 22. The relay transmission device sets a frequency channel for transmitting / receiving a signal among a plurality of transmission / reception frequency channels, and sets a predetermined frequency channel duration Ta using the received transfer expiration information. And
A frequency channel control unit configured to reset the frequency channel to a predetermined frequency channel that has been initialized when the frequency channel duration Ta elapses, wherein the transmission unit and the reception unit are configured to control the frequency channel set by the frequency channel control unit. 20. The relay transmission system according to claim 19, wherein signals are transmitted and received by using a relay station. 23. A transmission transmission device for relaying a data frame by transmitting and receiving at different times and sequentially transferring the data frame to one or more reception transmission devices via one or more relay transmission devices, A reception unit that receives a retransmission request including a frame number of a data frame that the reception transmission device has not been able to normally receive; a frame header analysis unit that extracts a frame number from the retransmission request received by the reception unit; A data frame generating unit that generates a data frame for transmission by adding a frame number; and a transmitting unit that transmits the data frame for transmission. The receiving and transmitting apparatus receives all of the plurality of transmitted data frames. If not, the retransmission request is transmitted by the reception transmission device, and the And answers, and wherein the retransmitting together one or more data frames to the receiving transmission apparatus, transmitting the transmission apparatus. 24. The transmission transmission apparatus according to claim 1, wherein the transmission required time for each data frame is sequentially subtracted from transfer expiration date information indicating a predetermined time until transfer is canceled, so that each data frame is transmitted. A transfer expiration date control unit that calculates the remaining time until canceling the transfer and sets it as new transfer expiration date information, and controls the transmission to stop if the new transfer expiration date information becomes negative. 24. The transmission transmission apparatus according to claim 23, further comprising: a transfer expiration date adding unit that adds the transfer expiration date information to the data frame. 25. A receiving and transmitting apparatus for relaying and transmitting a data frame by transmitting and receiving at different times from each other and sequentially transferring the data frame from a transmitting and transmitting apparatus via one or more relay transmitting apparatuses, A reception unit that receives the data frame; a frame header analysis unit that extracts a frame number from the data frame received by the reception unit; and a retransmission request that includes a frame number of the data frame that the reception transmission device could not normally receive. A retransmission request frame generation unit that generates the retransmission request, and a transmission unit that transmits the retransmission request.If all of the plurality of data frames transmitted by the transmission transmission device cannot be received, the retransmission request is generated. Transmitting, and the transmission transmission device collectively retransmits one or more data frames in response to the retransmission request DOO characterized, receiving transmission apparatus. 26. The reception transmission apparatus calculates a remaining time until the transfer is canceled by sequentially subtracting a time required from reception to transmission from transfer expiration information included in the data frame. A transfer expiration date control unit that controls the transmission to be stopped if the transfer expiration date information becomes negative, and that the transfer expiration date information is added to the retransmission request. The receiving and transmitting apparatus according to claim 25, further comprising a time limit adding unit. 27. A relay transmission device for performing transmission and reception at different times and relaying and transmitting a data frame by sequentially transferring the data frame from a transmission transmission device to a reception transmission device, wherein the relay transmission device comprises: A receiving unit that receives a retransmission request including a frame number of a data frame that cannot be normally received by a frame or a reception transmission device, and a transmission unit that transmits the data frame or the retransmission request received by the receiving unit, If the reception transmission device cannot receive all of the plurality of data frames transmitted by the transmission transmission device, the retransmission request is transmitted by the reception transmission device, and the transmission transmission device responds to the retransmission request. pls respond,
A relay transmission device, wherein one or more data frames are collectively retransmitted to the reception transmission device. 28. The relay transmission device, by sequentially subtracting a required time from reception to transmission from transfer expiration date information included in the data frame or the retransmission request, to obtain a remaining time until the transfer is canceled. Is calculated as new transfer expiration date information, and when the transfer expiration date information becomes negative, a transfer expiration date control unit that controls so as to stop transmission, the transfer expiration date information is the data frame or 28. The relay transmission device according to claim 27, further comprising a transfer expiration date adding unit added to the retransmission request.