JPH09247132A - Radio packet communication equipment and transmitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve transmission efficiency and use efficiency of a radio wave line by reducing communication times. SOLUTION: A transmitting device 10 divides transmission data into blocks of fixed length, the respective divided blocks are divided into the packets of fixed length and the packets are transmitted to a receiving device 30 by block unit. The receiving device is provided with a packet re-transmission requesting part 39 which returns a block reception mistake signal adding position information indicating the position of an error packet and requests re-transmission at the time of an error in the received packet inside the block. The transmitting device 10 is provided with a block generating part 19 which adds a re- transmission packet corresponding to the error packet to a part of plural new packets in the block to be transmitted after the one which adds the error packet based on the block reception mistake signal and, then, generates the block of fixed length so as to transmit it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio which divides transmission data into fixed-length blocks in a transmitting device, divides each divided block into fixed-length packets, and transmits the packets to the receiving device in block units. The present invention relates to a packet communication device and a transmission device.

[0002]

2. Description of the Related Art Conventional wireless packet communication devices include:
For example, a wireless packet transmission method described in JP-A-2-186733 is known. FIG. 11 shows a communication procedure in this wireless packet transmission system. In FIG.
When the terminal normally receives the m-th block, it sends a block ACK to the system side. The terminal receives the (m + 1) th block from the system side, but if the i-th packet in the block has an error, the terminal sends the block NAK (i) with the packet number i added to the system side. Send it back. The system side retransmits only the i-th packet of the (m + 1) th block to the terminal based on the block NAK (i) to which the packet number i is added.

As described above, in the conventional wireless packet transmission system, only the packet having an error in the block is retransmitted to improve the data transmission efficiency and reduce the data retransmission rate.

[0004]

However, in the above-mentioned conventional wireless packet transmission system, although the data transmission efficiency is improved and the data retransmission rate is reduced, if the i-th packet has an error, , Retransmits only the i-th packet having an error to the terminal. Therefore, when the amount of data to be transmitted becomes large, the total number of communications increases. That is, the communication time becomes long and the communication time for the block ACK and the block NAK other than the data becomes long. Therefore, the data transmission efficiency is reduced. Moreover, since the number of communications increases, the use efficiency of the wireless line also decreases.

Further, when the number of packets in a block increases, the number of retransmissions for transmitting one block on a transmission line having the same error rate increases, and further, the number of communication times for completing transmission of all data to be transmitted. Is increased and the data transmission efficiency is reduced.

It is a first object of the present invention to provide a wireless packet communication device and a transmitting device for improving the transmission efficiency and the wireless line usage efficiency by reducing the number of communications.

A second object of the present invention is to provide a radio packet communication apparatus and a transmission apparatus which improve the transmission efficiency by reducing the retransmission rate.

[0008]

The present invention employs the following means in order to solve the above-mentioned problems.

<Invention of Radio Packet Communication Device> Claim 1
In the invention, the transmission data is divided into fixed-length blocks, each divided block is divided into fixed-length packets, and the packets are transmitted in block units. A receiving device for receiving the packet, the receiving device returns a block reception failure signal including position information indicating the position of the error packet to the transmitting device when the packet in the received block has an error, and transmits the packet to the transmitting device. A packet retransmission requesting unit for requesting retransmission of the packet, and the transmitting device, based on a block reception failure signal from the packet retransmission requesting unit, transmits a plurality of new packets in a block to be transmitted next to the block including the error packet. A block for creating and transmitting the fixed-length block by adding a retransmission packet corresponding to the error packet to a part of It characterized by having a preparation unit.

According to the present invention, when the packet in the block received by the receiving device from the transmitting device has an error,
The packet retransmission request unit returns a block reception failure signal including position information indicating the position of the error packet to the transmission device to request packet retransmission. The block creation unit adds the retransmission packet corresponding to the error packet to a part of a plurality of new packets in the block to be transmitted next to the block including the error packet based on the block reception failure signal, thereby fixing the fixed length. Create a block and send it. As a result, the number of times of communication is reduced as compared with the number of times of communication in which the retransmission packet and the new packet are transmitted separately, so that it is possible to improve the transmission efficiency and the usage efficiency of the wireless line.

According to a second aspect of the present invention, transmission data is divided into fixed-length blocks, each divided block is divided into fixed-length packets, and the packets are transmitted in block units. A receiving device for receiving a packet in block units, wherein the receiving device transmits a block reception failure signal including position information indicating a position of the error packet when the packet in the received block has an error. The device further includes a packet retransmission request unit for returning the packet to the device and requesting the packet to be retransmitted, and the transmission device transmits one block or more after a block including the error packet based on a block reception failure signal from the packet retransmission request unit. By adding a plurality of retransmission packets corresponding to the error packet to a part of the plurality of new packets in the power block, It characterized by having a block creation unit that creates and sends a block of fixed length.

According to the present invention, when the receiving device has an error in the packet in the block received from the transmitting device,
The packet retransmission request unit returns a block reception failure signal including position information indicating the position of the error packet to the transmission device to request packet retransmission. Then, the block creation unit divides a plurality of retransmission packets corresponding to the error packet into a part of a plurality of new packets to be transmitted after one or more blocks including the error packet based on the block reception failure signal. The fixed-length block is created by adding and is transmitted. As a result, the retransmission rate can be reduced, and the reduction of the retransmission rate improves the transmission efficiency. Further, since the duplicated retransmission packet is received by the receiving device, the reception rate of the retransmission packet is improved.

According to a third aspect of the present invention, the block creation section detects a block number included in the retransmission packet and a block number included in each new packet, and the retransmission packet detected by the detection section. When the difference between the block number and the block number of each new packet is larger than a predetermined value, a retransmission packet overlapping unit that arranges retransmission packets in the fixed length block in an overlapping manner is provided.

According to the present invention, when the detection unit detects the block number included in the retransmission packet and the block number included in each new packet, the retransmission packet duplication unit
If the difference between the block number of the detected retransmitted packet and the block number of each new packet is larger than a predetermined value, the retransmitted packets are overlapped in the fixed-length block and transmitted, so that the same error packet is generated. On the other hand, when multiple retransmission requests are made, the retransmission rate can be reduced by transmitting duplicated retransmission packets.

In the invention of claim 4, the receiving device determines whether or not at least one of the duplicated retransmission packets from the transmitting device is correct, and the packet retransmission requesting unit is configured to duplicate the duplicated retransmission packet. When both the retransmitted packets are erroneous, the block reception failure signal is returned to the transmission device to request retransmission of the packet.

According to the present invention, the packet retransmission requesting unit returns a block reception failure signal to the transmitting device to request retransmission of the packet when the duplicated retransmission packets are both erroneous. The creation unit will send duplicated retransmission packets.

<Invention of Transmitting Device> According to the invention of claim 5, transmission data is divided into fixed-length blocks, each divided block is divided into fixed-length packets, and the packets are transmitted to the receiving device in block units. In the transmitting device, the plurality of blocks in the block to be transmitted next to the block including the error packet based on the block reception failure signal from the receiving device including the position information indicating the position of the error packet in the block received by the receiving device And a block creation unit that creates and transmits the fixed-length block by adding a retransmission packet corresponding to the error packet to a part of the new packet.

According to a sixth aspect of the present invention, in the transmitting device, the transmission data is divided into fixed-length blocks, each divided block is divided into fixed-length packets, and the packets are transmitted to the receiving device in block units. A plurality of new packets in the block to be transmitted after one block or more of the block including the error packet based on the block reception failure signal from the receiving device including the position information indicating the position of the error packet in the block received by the receiving device. It is characterized by further comprising a block creation unit for creating and transmitting the fixed-length block by adding a plurality of retransmission packets corresponding to the error packet to a part.

According to a seventh aspect of the present invention, the block creation section detects a block number included in the retransmission packet and a block number included in each new packet, and the retransmission packet detected by the detection section. When the difference between the block number and the block number of each new packet is larger than a predetermined value, a retransmission packet overlapping unit that arranges retransmission packets in the fixed length block in an overlapping manner is provided.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a wireless packet communication device according to the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 shows a circuit configuration of a first embodiment of a radio packet communication apparatus of the present invention. The wireless packet communication device shown in FIG. 1 divides transmission data into fixed-length blocks, divides each divided block into fixed-length packets, and transmits the packets in block units. The receiving device 30 receives the packet from each block in units of 10.

The transmitter 10 comprises a radio section 11, a data buffer 13, a data division section 15, a control section 17, a block creation section 19, and an external connection section 21. The data buffer 13 stores all transmission data to be transmitted to the receiving device 30. The data dividing unit 15 divides the data to be transmitted into fixed-length blocks, divides each divided block into fixed-length packets, and divides the divided blocks into data buffers 13.
Output to

The data buffer 13 stores each block including a plurality of packets divided by the data dividing unit 15. FIG. 2 shows each block including a plurality of packets stored in the data buffer 13. Each block B1-B
n is composed of m packets (also referred to as data or packet data) P1 to Pm.

FIG. 3 shows the data format. FIG.
(A) shows the format of each packet configuration. Each packet has the block number to which the packet belongs.
(Number) information, its packet number (number) information, data, and error detection code (CRC). FIG.
(B) shows one block to be transmitted which is composed of m packets. FIG. 3C shows a return block to be returned by the receiving device, which will be described later.

The control unit 17 is composed of a CPU and the like, and has a radio unit 11, a data buffer 13, and a data dividing unit 1.
5. Control the block creation unit 19 and the external connection unit 21.
The wireless unit 11 transmits the packets stored in the data buffer 13 to the receiving device 30 in block units via the control unit 17. Regarding the block creation unit 19, the receiving device 30
Since the processing is performed based on the signal from, it will be described later.

Next, the configuration of the receiving device 30 will be described. The receiving device 30 includes a radio unit 31, a data buffer 33, a control unit 37, a packet retransmission request unit 39, and an external connection unit 41.

The radio unit 31 receives the packet in block units from the transmitter 10 and sends it to the control unit 37. Control unit 37
Is composed of a CPU and the like, and the wireless unit 31 and the data buffer 3
3, controlling the packet resend request unit 39 and the external connection unit 41, and determining whether or not the packet in block units from the transmission device 10 is correct.

The data buffer 33 stores the packet in block units from the transmission device 10 under the control of the control unit 37. When the packet resend request unit 39 determines that the packet in the block received by the control unit 37 has an error, it sends a block reception failure signal including position information indicating the position of the error packet via the wireless unit 31. Transmitter 1
It is returned to 0 to request retransmission of the packet.

FIG. 3C shows a return block to be returned by the receiving device as described above. 1 block for return
It is composed of m bits corresponding to the number m of packets in the block. The return block is configured by setting all bits "0" in the case of ACK (block reception success) and setting the bit in the position corresponding to the incorrect packet to "1" in the case of NAK. Failure signal (B-NA
K) will be returned.

The block creating unit 19 provided in the transmitting device 10 receives a plurality of new packets in the block to be transmitted next to the block including the error packet based on the block reception failure signal from the packet retransmission requesting unit 39. The fixed-length block is created and transmitted by adding a retransmission packet corresponding to the error packet to a part of.

In the packet resend request unit 39, for example, the program stored in a memory (not shown) is the C
It may be configured by a function realized by PU, that is, software.

Next, the operation of the wireless packet communication device thus configured will be described using the communication procedure shown in FIG. First, in the transmission device 10, the control unit 17
From the data buffer 13 to the block B1 (packet 11
-Read packet 1m) and the wireless unit 11 blocks B1
(Packet 11-Packet 1 m) is transmitted to the receiving device 30.

On the other hand, in the receiving device 30, block B
1 (packet 11-packet 1 m) is taken into the control unit 37 via the wireless unit 31. The control unit 37 determines whether or not each packet of the block B1 is correct. When all the packets of the block B1 are correct, the receiving device 30 returns the block reception success signal (B-ACK) to the transmitting device 10.

In this way, the transmitting device 10 transmits the packet to the receiving device 30 in block units. Then, the transmission device 10 sets the block Bk (packet k1-packet k
m) is transmitted to the receiving device 30, and the control unit 37 determines whether or not each packet of the block Bk is correct, for example, it is determined that the second packet k2 in the block Bk is incorrect.

In this case, the packet resend request unit 39
Sets only the second bit of the return block to "1" as shown in FIG. 5, and the block reception failure signal (B-NA) including the position information indicating the position of the error packet k2.
As K), the packet is returned to the transmitter 10 to request retransmission of the packet.

Then, in the transmitting apparatus 10, the block creating section 19 reads the packet k2 from the data buffer 13 as the retransmission packet k2 based on the block reception failure signal from the packet retransmission request section 39. Further, the block creation unit 19 causes some of the new packets in the block Bk + 1 to be transmitted next to the block Bk including the error packet k2 to be part of the packets k + 11 to k + 1.
By adding a retransmission packet k2 corresponding to the error packet k2 to m-1, a fixed-length block Bk + 1 composed of m packets is created and transmitted.

That is, a fixed-length block Bk + 1 (k2, k + 11 to k + 1m-1) as shown in FIG. 6 is created and transmitted. Such a series of procedures is repeated until there is no transmission data.

As described above, according to the first embodiment, when retransmitting a packet, not only the retransmitted packet corresponding to the erroneous packet but also a partial packet of the block to be transmitted next is added. And send it as a fixed-length block.

Therefore, since the number of times of communication is reduced in this embodiment as compared with the conventional wireless packet transmission system in which only the retransmission packet is transmitted and then the block to be transmitted is transmitted, the transmission efficiency is improved. In addition to being able to improve the efficiency of use of the wireless line.

<Second Embodiment> FIG. 7 shows a circuit configuration of a second embodiment of the radio packet communication apparatus of the present invention. The wireless packet communication device shown in FIG. 7 has the functional configuration of the first embodiment, and further reduces the packet retransmission rate by duplicating an erroneous packet in a block when retransmitting the packet. Is.

In FIG. 7, the transmitting device 10a comprises a radio section 11, a data buffer 13, a control section 17a, a data dividing section 15, a block creating section 19a, and an external connecting section 21. The receiving device 30a includes a wireless unit 31,
The data buffer 33, the control unit 37a, the packet retransmission request unit 39a, and the external connection unit 41 are provided.

The block creating section 19a is used by the receiving device 3
By adding a retransmission packet corresponding to the error packet to a part of a plurality of new packets in a block to be transmitted after one or more blocks including the error packet based on the block reception failure signal from 0a. The fixed-length block is created and transmitted, and includes a detection unit 23, a comparison unit 25, and a retransmission packet duplication unit 27.

The detecting section 23 detects the block number included in the retransmission packet and the block number included in each new packet. The comparison unit 25 compares the difference between the block number of the retransmission packet detected by the detection unit 23 and the block number of each new packet with a predetermined value. When the difference between the block number of the retransmitted packet and the block number of each new packet is larger than a predetermined value, the retransmitted packet duplication unit 27 duplicately arranges the retransmitted packets in the fixed-length block.

The control unit 37a in the receiving device 30a is
It is determined whether at least one of the duplicated retransmission packets from the transmitter 10a is correct. The packet retransmission request unit 39a returns the block reception failure signal to the transmission device 10a and requests packet retransmission when the duplicated retransmission packets are both incorrect.

The rest of the configuration is the same as that of the first embodiment, and the same parts are designated by the same reference numerals and their details are omitted.

Next, the operation of the radio packet communication apparatus thus configured will be described with reference to the flowchart showing the packet retransmission procedure shown in FIG. Here, according to the communication procedure described in the first embodiment, the transmission of the second transmission block has already been completed, and the packet 2m including the retransmission packet 11 and the packets 31 to 31 as shown in FIG.
A retransmission procedure when transmitting the third transmission block composed of m packets of 3m−2 will be described as an example.

In this example, since the quality of the transmission path is poor and the retransmission request is made twice from the receiving device 30a, the retransmission packet 11 is included in the third block.

First, the detection unit 23 detects the block number included in the retransmission packet and the block number included in each new packet (step S11). Comparison unit 25
Is a difference between the block number (the smallest block number) of the retransmission packet detected by the detection unit 23 and the largest block number of the new packet, which is a predetermined value, for example, 1
It is determined whether or not the value exceeds (step S13).

When the difference between the block number of the retransmitted packet and the largest block number of the new packet is larger than a predetermined value, the retransmitted packet duplication section 27 receives the retransmitted packets by overlappingly arranging them in the fixed length block. Device 30
to a (step S15).

In the example shown in FIG. 9, the maximum block number (packet 31) is "3" and the minimum block number (packet 11) is "1". For this reason, the difference is larger than the predetermined value "1", so that the packet 11 having the smallest block number is arranged in an overlapping manner as shown in FIG. Since the two packets 11 are arranged, the last packet in the fixed-length block is the packet 3
m-3.

On the other hand, the radio unit 31 in the receiving device 30a
When the control unit 37a receives the fixed-length block from the transmission device 10a, the control unit 37a determines whether at least one of the duplicated retransmission packets in the fixed-length block is correct (step S17). Control unit 37
a is the case where at least one of the duplicated retransmission packets in the fixed-length block is correct,
Take in one of the correct retransmitted packets (step S
19).

Then, the packet retransmission request unit 39a
Sets the bit corresponding to each packet position of the return packet to "0" (successful reception) (step S21).

On the other hand, if it is determined in step S17 that both duplicated retransmission packets are erroneous, the packet retransmission request unit 39a sets the bit corresponding to each packet position of the return packet to "1" (reception). It is set to "failure" and a packet retransmission request is made (step S23).

The packet retransmission request unit 39a returns the block reception failure signal to the transmitter 10a to request packet retransmission when the duplicated retransmission packets are both incorrect. Then, the block creating unit 19a
Transmits a fixed-length block including a retransmitted packet and a new packet that are duplicated based on the retransmission request. Then, this retransmission request is made until the reception of the retransmission packet is successful. Further, this series of operations is repeated until there is no data to be transmitted.

In step S13, if the difference between the block numbers of the packets is less than or equal to the predetermined value, the transmission block is transmitted as it is (step S25), and the packet processing of the receiving device 30a is performed (step S2).
7). That is, in this case, the same operation as that of the first embodiment is performed.

As described above, according to the second embodiment, when the retransmission request is continuously made because the quality of the transmission line is poor and the same packet is erroneous multiple times, the error packet is dealt with. Since the retransmission packets to be transmitted are overlapped in the block and transmitted, the retransmission rate can be reduced. Also, the transmission efficiency is improved by reducing the retransmission rate. further,
Since the duplicated retransmission packet is received by the receiving device 30a, the reception rate of the retransmission packet is improved.

In the second embodiment, the predetermined value is "
Although the predetermined value may be set to “0”, for example, in this case, if the difference between the block number of the retransmission packet and the block number of the new packet is “1”, it is duplicated. Retransmitted packets can be arranged in blocks and transmitted, that is, duplicated retransmitted packets may be transmitted when the receiver 30a makes a single retransmission request. It may be an integer value of 2 or more.

Further, instead of the duplicated retransmission packets, three identical retransmission packets may be arranged. With this, the retransmission rate is further reduced, and the reception rate of the retransmission packet is further improved in the receiving device 30a.

[0059]

According to the present invention, the block creation unit causes a plurality of new packets in the block to be transmitted next to the block including the error packet based on the block reception failure signal including the position information indicating the position of the error packet. A fixed-length block is created and transmitted by adding a retransmission packet corresponding to an error packet to a part of. as a result,
Since the number of times of communication is reduced as compared with the number of times of communication in which the retransmission packet and the new packet are transmitted separately, it is possible to improve the transmission efficiency and the usage efficiency of the wireless line.

Also, the block creation unit may include a plurality of retransmission packets corresponding to the error packet as a part of the plurality of new packets to be transmitted after one or more blocks including the error packet based on the block reception failure signal. A fixed-length block is created by adding the number of blocks and transmitted. As a result, the retransmission rate can be reduced, and the reduction of the retransmission rate improves the transmission efficiency.

Further, when the difference between the block number of the detected retransmitted packet and the block number of each new packet is larger than a predetermined value, the retransmitted packets are overlapped and transmitted in the fixed-length block, and therefore the same. When there are multiple retransmission requests for the error packet, the retransmission rate can be reduced by transmitting the duplicated retransmission packets.

Further, since the packet resend request unit sends a block reception failure signal back to the transmitter to request resending of the packet when both duplicated resent packets are erroneous,
The transmission of duplicated retransmission packets can be repeated.

[Brief description of drawings]

FIG. 1 is a first embodiment of a wireless packet communication device according to the present invention;
FIG.

FIG. 2 is a diagram showing each block into which transmission data is divided.

FIG. 3 is a diagram showing a data format.

FIG. 4 is a diagram showing a communication procedure of the wireless packet communication device.

FIG. 5 is a diagram showing an example of a configuration of a return block.

FIG. 6 is a diagram showing a transmission block including a retransmission packet and a new packet according to the first embodiment of the present invention.

FIG. 7 is a second embodiment of the wireless packet communication device of the present invention.
FIG.

FIG. 8 is a diagram showing a packet retransmission procedure according to the second embodiment.

FIG. 9 is a diagram showing an example of a transmission block according to the second embodiment.

FIG. 10 is a diagram showing a transmission block including a duplicated retransmission packet and a new packet according to the second embodiment of the present invention.

FIG. 11 is a diagram showing a communication procedure of a conventional wireless packet transmission system.

[Explanation of symbols]

 10 Transmitting device 11,31 Radio part 13,33 Data buffer 15 Data dividing part 17,37 Control part 19 Block creating part 21,41 External connection part 23 Detecting part 25 Comparing part 27 Retransmitting packet duplication part 30 Receiving device 39 Packet resending request Department

Claims (7)

[Claims] 1. A transmission device that divides transmission data into fixed-length blocks, divides each divided block into fixed-length packets, and transmits packets in block units; and a packet from the transmission device in block units. And a receiving device for receiving a block reception failure signal including position information indicating the position of the error packet when the packet in the received block has an error, and the receiving device returns the block reception failure signal to the transmitting device. A packet retransmission request unit for requesting retransmission of a packet, wherein the transmission device has a plurality of new blocks in a block to be transmitted next to a block including the error packet based on a block reception failure signal from the packet retransmission request unit. A block for creating and transmitting the fixed-length block by adding a retransmission packet corresponding to the error packet to a part of the packet Wireless packet communication apparatus characterized by having a click creation unit. 2. A transmission device that divides transmission data into fixed-length blocks, divides each divided block into fixed-length packets, and transmits packets in block units; and a packet from the transmission device in block units. And a receiving device for receiving a block reception failure signal including position information indicating the position of the error packet when the packet in the received block has an error, and the receiving device returns the block reception failure signal to the transmitting device. A packet retransmission request unit for requesting retransmission of a packet, wherein the transmitting device has a plurality of blocks to be transmitted after one or more blocks including the error packet based on a block reception failure signal from the packet retransmission request unit. The fixed-length block is added by adding a plurality of retransmission packets corresponding to the error packet to a part of the new packet of Wireless packet communication apparatus characterized by having a block creation unit to create and send. 3. The block creating unit detects a block number included in the retransmitted packet and a block number included in each new packet, and a block number of the retransmitted packet detected by the detecting unit. The wireless packet according to claim 2, further comprising: a retransmission packet overlapping section that arranges retransmission packets in the fixed-length block in an overlapping manner when the difference from the block number of the new packet is larger than a predetermined value. Communication device. 4. The receiving device determines whether or not at least one retransmission packet of the duplicated retransmission packets from the transmission device is correct, and the packet retransmission requesting unit collects the duplicated retransmission packets together. The wireless packet communication device according to claim 3, wherein when the error is erroneous, the block reception failure signal is returned to the transmitting device to request packet retransmission. 5. A transmission device that divides transmission data into fixed-length blocks, divides each divided block into fixed-length packets, and transmits the packets in block units to a reception device, wherein the reception device receives the packets. A part of a plurality of new packets in a block to be transmitted next to the block including the error packet based on the block reception failure signal from the receiving device including the position information indicating the position of the error packet in the block. A transmitting apparatus comprising: a block creating unit that creates and transmits the fixed-length block by adding a corresponding retransmission packet. 6. A transmission device that divides transmission data into fixed-length blocks, divides each divided block into fixed-length packets, and transmits the packets to the reception device on a block-by-block basis, wherein the reception device receives the packets. Based on a block reception failure signal from a receiving device including position information indicating the position of an error packet in the block, the error is caused in a part of a plurality of new packets in the block to be transmitted after one block or more of the block including the error packet. A transmitting apparatus comprising: a block creation unit that creates and transmits the fixed-length block by adding a plurality of retransmission packets corresponding to the packets. 7. The block creation unit detects a block number included in the retransmission packet and a block number included in each new packet, and a block number of the retransmission packet detected by the detection unit and The transmission device according to claim 6, further comprising: a retransmission packet duplication unit that arranges retransmission packets in the fixed-length block in an overlapping manner when the difference from the block number of the new packet is larger than a predetermined value. .