JP3349926B2 - Receiving control device, communication control system, and communication control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transmission control apparatus, a reception control apparatus, a communication control system and a communication control method for transmitting and receiving data in packet units, and more particularly to an improvement in throughput and line utilization efficiency in retransmitting data. It relates to an aiming device.

[0002]

2. Description of the Related Art FIG. 18 is a diagram showing an example of a conventional transmission sequence, in which transmission data is divided into a plurality of blocks, error detection data is added to each block, and transmission is performed. It shows a method of retransmitting only blocks. In the sequence shown in FIG. 18, data in the data format shown in FIG.
The receiving side requests retransmission of an erroneous block. In the example shown in FIG. 18, since only the first block is correctly received at the first time, only the second and third blocks are retransmitted at the second transmission. In the second transmission, since only the third block was correctly received, the receiving side requests retransmission of the second block. Then, in the third transmission, the second block is transmitted.

FIG. 20 is a diagram showing another example of a conventional transmission sequence, which shows a method of dividing transmission data into a plurality of blocks and continuously transmitting them. The data format is the same as in FIG. In FIG. 20, FIG.
9 is transmitted three times and transmitted to the receiving side. The receiving side extracts a block that has been correctly received from the data three times, and transmits an acknowledgment signal to the transmitting side when all blocks have been correctly received.

[0004] FIG. 21 is a diagram showing an outline of a method of dividing broadcast data into blocks and transmitting the blocks. FIG.
Then, the data packets of blocks (1) to (10) are transmitted from the base station. The mobile station 1 receives all the blocks normally, receives polling from the base station, and transmits ACK. The mobile station 2 has abnormal blocks (2) and (7), and the mobile station 3 has blocks (5), (7) and (8).
Are abnormal, and each of them receives polling from the base station and adds an erroneous block number to the NAK and transmits it. The base station simultaneously transmits the retransmission data of each of the mobile station 2 and the mobile station 3 as retransmission data.

FIG. 22 shows a data format used in a communication system conforming to HDLC. In HDLC, the HDLC format information field I is divided into a plurality of subfields SF and transmitted. If there is an error, only the wrong subfield is retransmitted.

[0006]

However, in the conventional system in which transmission data is divided into a plurality of blocks, error detection data is added to each block and the blocks are transmitted, and only blocks having errors are retransmitted, The length is the same as when the error occurred and is fixed. That is, the block error rate is the same as the first data transmission because the transmission block length is the same. Therefore, when the error rate is high, the probability of erroneous retransmission data also increases. As a result, retransmission is performed frequently, the throughput decreases, and the line utilization efficiency deteriorates.

[0007] In a transmission system in which transmission data is divided into a plurality of blocks and transmitted continuously, continuous transmission is performed even when the line quality is good, and data which is many times as much as information is always transmitted. And the line utilization efficiency deteriorates.

[0008] In the system in which broadcast data is divided into blocks and transmitted, retransmission data is also transmitted to a mobile station that has already received all blocks normally, so that the mobile station receives only the retransmission data. By doing so, it is erroneously recognized that all data could not be received, a retransmission request is made in the next polling, and a state mismatch with the base station occurs. In addition, if there are terminals with a large number of error blocks and terminals with a small number of blocks, retransmission data includes data for terminals with many errors and terminals with many errors, so the time to receive retransmission data is unnecessarily long. Could be.

In the conventional method in which the information field of the HDLC format is divided into a plurality of subfields, if the address field, the control field, and the subframe are incorrect, it is determined that there is an error in the address field and the control field. Since it cannot be determined, there is a possibility that the operation will be performed with incorrect address and control information.

[0010] Further, in the conventional system, the transmitting side transmits a reception response (normal reception (A
If CK) and retransmission request (NAK)) cannot be received normally due to an error or the like, the transmitting side transmits retransmission data due to a reception response wait timeout. By the way, when a timeout occurs for retransmission data including only an erroneous block, the retransmission data at this time includes only an erroneous block. When the receiving side normally receives the retransmission data including only the erroneous block, it responds with an ACK, and then waits in expectation of receiving a transmission packet including all the blocks. . However, when the ACK has not reached the transmitting side, the transmitting side retransmits a packet including only an erroneous block. For this reason, the receiving side interprets the retransmitted data sent as new data in the communication procedure and receives it.However, this received packet contains only erroneous blocks and all blocks are included. Therefore, it is determined that the data is not correct, and a retransmission request is made. That is, retransmission of already received data is requested again, and unnecessary data transmission occurs, and inconsistency between states on the transmission side and the reception side may occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first object of the present invention is to provide a transmission control device which lowers a block error rate at the time of data retransmission and increases throughput and line utilization efficiency. An object of the present invention is to provide a reception control device.

It is a second object of the present invention to provide a transmission control device and a reception control device which reduce the processing load and prevent the state mismatch due to the reception of unnecessary retransmission data.

[0013]

[0014]

[0015]

[0016]

[0017]

In order to achieve the above object, a reception control device according to the present invention performs data communication in packet units, and retransmits data when an error is detected in a received packet. An error detection unit that performs error detection of a block included in a received packet based on an error detection code added to each block on a transmission side, and an error is detected. Retransmission control means for designating the erroneous block and transmitting a retransmission request, block assembly means for assembling a normally received block as a received packet,
In the case where the transmitting side divides the corresponding block in response to the retransmission request transmitted by the retransmission control unit and transmits the divided block, if the error detection unit detects an error in the retransmission block transmitted from the transmitting side, the retransmission is performed. Block data generating means for generating block data according to a comparison result between the block and the erroneous block, wherein the block data generating means comprises a retransmission block in which an error is detected and the erroneous block. , And when there is a different bit, block data is generated by inverting the corresponding bit of the retransmission block, and the error detection unit outputs the block data generated by the block data generation unit. The block assembling means detects an error by the error detecting means. When bought, the block data generating means is intended to assemble the received packet by the block data generated.

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

A communication control system according to the present invention performs character data communication on a packet basis and transmits a retransmission request when an error is detected in received data, and retransmits data in response to the retransmission request. In a communication control system having a transmission control device, the transmission control device includes: a blocking unit that divides a transmission packet into a plurality of blocks; a data transmission unit that transmits blocked transmission data; and a block in which an error is detected. When a retransmission request including data is received, the received block data including an error is compared with the stored correct block data corresponding to the block data, and only different character data is extracted from the block data. and a <br/> Ru sender retransmission control unit be retransmitted Te, the reception control unit,
Storage means for storing the received packets temporarily, the error detection block contained in the received packet, send
An error detection unit that performs, based on the error detection code added to the respective blocks in the signal side, and adds it to the block data for which the error in the retransmission request when an error is detected by said error detection means has a receiving-side retransmission control means for transmitting, and a block assembly means for assembling the received packets based on the block data or character data has been normally received, incorrectly retransmission should do block data
It consists only of character data .

[0025]

[0026]

[0027]

[0028]

[0029]

According to the communication control method of the present invention, in a communication control system having a communication control device for performing data communication in units of packets, a data transmission step in which a transmission-side communication control device divides a transmission packet into a plurality of blocks for transmission When an error is detected in a block received by the communication control device on the receiving side based on an error detection code added to each block on the transmitting side, a retransmission request is issued by designating the block in which the error is detected. A retransmission requesting step; a retransmission step of further dividing only the block in which the error is detected in the transmission side communication control device into a plurality of blocks and retransmitting the block; and a transmission from the transmission side communication control device in the reception side communication control device. If an error is detected in the received retransmission block, the retransmission block and the error are detected. Comparing each bit corresponding to the lock and, when a different bit exists, a block data generating step of generating block data by inverting the bit of the retransmission block; and a block data generated by the block data generating step. An error detection step of performing error detection on, and when no error is detected by the error detection step, including a block assembly step of assembling a received packet with the block data generated by the block data generation step, The correct block data is automatically generated in the communication control device on the receiving side.

[0031]

[0032]

[0033]

According to the communication control method of the present invention, in a communication control system having a communication control device for performing character data communication on a packet basis, a data transmission in which a transmission packet is divided into a plurality of blocks by a transmitting communication control device and transmitted. Steps: When an error is detected based on the error detection code added to each block in the packet received by the receiving side communication control device, the error is detected .
A retransmission request step for a retransmission request block data as it is added to, the correct block data that has been stored corresponding to the block data and the block data included in the retransmission request received at the transmitting-end communication control device A retransmission step of comparing and extracting only different character data from the block data and retransmitting, and assembling a reception packet based on the character data normally received and the block data already received in the receiving side communication control device. And a block assembling step.

[0035]

[0036]

Preferred embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a block diagram showing a communication control device according to the present embodiment. This communication control device has both a function as a transmission control device and a function as a reception control device according to the present invention.

The communication control device 2 has a terminal interface 3, a CPU 4, a memory 5, a blocking unit 6, a block assembling unit 7, and a wireless interface 8. The terminal interface 3 is a means for connecting the data terminal 1 which issues transmission data or finally receives received data. The CPU 4 collectively performs not only transmission / reception control in the device 2 but also operation control of the entire device by operating an OS, a communication protocol, an application, and the like. Further, the CPU 4 is provided as retransmission control means, and when an error is detected in data transmission, the communication control device (transmission control device) for transmitting data transmits only the block data in which the error is detected. Further, after being divided into a plurality of blocks, retransmission is performed. When an error is detected, the communication control device (reception control device) that receives data transmits a retransmission request by designating the erroneous block. The memory 5 is storage means for temporarily storing communication data. Blocking unit 6
Is a block unit for dividing a transmission packet into a plurality of blocks, and operates at the time of data transmission. The block assembling unit 7 is a block assembling unit that assembles a normally received block as a received packet, and is an error detecting unit that detects an error of a block included in the received packet. The block assembling section 7 operates when receiving data. The wireless interface 8 is a data transmitting unit that transmits the blocked transmission data, and a data receiving unit that receives the blocked data.
Wirelessly transmits data to another communication control device via the communication device.

Since the retransmission data is actually transmitted via the wireless interface 8, the wireless interface 8 can be said to be strictly a part of the retransmission control means for performing the retransmission processing. Similarly, in the above description, CP
Although U4 is used as the retransmission control means, since the block data is also generated at the time of retransmission, the blocking unit 6 also becomes a part of the retransmission control means. In addition to the above-described configuration, for example, the communication control device 2 on the transmission side naturally has means for receiving and interpreting a retransmission request or a reception response (ACK) transmitted from the reception side. Since a particular one may be used and is not a characteristic component of the present invention, it will not be particularly described. In this embodiment, retransmission is performed up to twice for convenience of explanation. The same applies to other embodiments described later.

FIG. 2 is a diagram showing a frame format of transmission data used in the present embodiment. In FIG. 2, (a) shows the format of a packet that is divided into blocks.
Bytes are used as block numbers, and the remaining two bytes are inserted with 0s for use as sub-block numbers during retransmission. (B) is the format of the first retransmission, in which the retransmission block is divided into sub-blocks, and the sub-frame number is inserted in the second byte of the block number frame. (C) is the second retransmission format, in which the subblock to be retransmitted is further divided into subblocks, and the subframe number is inserted into the third byte of the block number frame.

FIG. 3 is a flowchart when the communication control device 2 operates as a transmission control device (data transmission side) in the present embodiment, and FIG. It is a flowchart at the time of operating as a device (data receiving side). Hereinafter, the operation in the present embodiment will be described based on these drawings. In the present embodiment, a case where data is transmitted from data terminal A (communication control device A) to data terminal B (communication control device B) will be described as an example.

First, when a data transmission request is generated in the data terminal A (S 1), the packet is transferred to the memory 5 via the terminal interface 3. Memory 5
Is divided into a fixed block length by the blocking unit 6 (S2), and a block number and a code CRC for error detection are added to each block (S3). The block number is placed in the first byte of the block number frame, and the remaining two bytes are set to 0. FIG.
The packet blocked as shown in (a) is transmitted to the communication control device B via the wireless device 9 after data for wireless transmission such as a synchronization bit is added by the wireless interface 8 (S4).

The communication control unit B on the receiving side performs error detection for each block included in the packet received via the wireless interface 8 by the block assembling unit 7 (S2).
1, 22, 23), and the block that has been normally received is stored in the memory 5 (S24). If there is no error, a reception response is sent to the communication control device A (S25, 26), and
The assembled data is transferred to the memory 5 and transmitted to the data terminal B via the terminal interface 3 (S27). If there is an erroneous block, the block number is included in the retransmission request packet and transmitted to the communication control device A (S25, 28).

Upon receiving the retransmission request (S6, 7, 9), the communication control device A reads out the corresponding block from the memory 5 based on the block number contained in the retransmission request packet, and It is divided into two sub-blocks (S10), and a block number, a sub-block number, and an error detection code are added to each block number frame according to the above-described rule and transmitted (S11, S11).
4).

The communication control unit B detects an error of each block included in the packet with respect to the data received via the wireless interface 8 by the block assembling unit 7 (S21, 22, 23) and receives the data normally. The resulting block is stored in the memory 5 (S24). If there is no error, a reception response is sent to the communication control device A (S25, 2).
6) The data assembled in the block normally received first and the block normally received by retransmission are stored in the memory 5.
To the data terminal B via the terminal interface 3 (S27). If there is an erroneous block at the time of retransmission, the block number is included in the retransmission request packet and transmitted to the communication control device A (S2).
5, 28). Until all data can be received without error (S25-2
7) Alternatively, this procedure is repeated up to twice for retransmission, and packet transmission is completed (S29).

FIG. 5 is a diagram showing an example of the transmission sequence in the present embodiment, and the above processing procedure will be described more specifically with reference to FIG.

The communication control device A transmits blocks 1 to 3 for the first time. The communication control device B correctly receives only the first block in the first transmission, requests retransmission of the blocks 2 and 3, and stores the first block. The communication control device A divides the blocks 2 and 3 into subframes (blocks 2-1 and 2-2 and blocks 3-1 and 3-2), and retransmits them. The communication control device B stores only the subframes 3-1 of the blocks 2 and 3 that have been correctly received, and requests a retransmission of only the subframe 3-2 of the block 3 in which an error has occurred. Communication control device A
Converts the subframe 3-2 of the block 3 into two more subframes (the block 3-2-1 and the block 3-2-
After dividing into 2), resend. Upon successfully receiving the subframes 3-2-1 and 3-2-2 of the block 3-2, the communication control device B transmits and stores a reception response.
All the blocks normally received by such a procedure are assembled and transmitted to the data terminal B.

As described above, according to the present embodiment, 1
By dividing a packet into a plurality of blocks and further dividing only an erroneous block into sub-blocks at the time of retransmission and retransmitting the subblock, efficient transmission can be performed even in a bad line condition. That is, the amount of transfer data can be reduced by retransmitting only the block having an error, and the block error rate can be reduced by halving the block length. As a result, the number of retransmissions and the retransmission time can be relatively shortened, and the throughput and the line utilization efficiency can be improved.

In the above example, the data transmission is performed from the communication control device A to the communication control device B. However, the data transmission can be performed in the same manner in the reverse order. Also,
Even when transmitting data from a transmission control device having only a data transmission function to a reception control device having only a data reception function, data transmission can be performed in exactly the same procedure.

An error occurring in the data transmission process on the data transmission side is detected by receiving a retransmission request packet from the communication control device on the reception side, and the block containing the error is included in the retransmission request packet. Although it can be specified by the block number, it can be applied to other communication procedures that do not use the retransmission request packet. Even when a reception response is not received from the receiving side within a predetermined time, it is considered that an error has been detected in all blocks, and the present embodiment can be applied by dividing the blocks into sub-blocks of all blocks.

Embodiment 2 In the first embodiment, when an error is detected, the erroneous block is divided into sub-blocks. In the present embodiment, the erroneous block is continuously transmitted. It is characterized by doing so. In the present embodiment,
Continuous transmission is performed only when there is a retransmission request. Although the device configuration in the present embodiment is not shown because it is the same as that in the first embodiment, the CPU 4 in the present embodiment
When an error is detected in the data transmission, it is provided as retransmission control means for continuously transmitting and retransmitting only the block data in which the error is detected.

FIG. 6 is a diagram showing a frame format of transmission data used in the present embodiment. In FIG. 6, a header required for wireless transmission is provided at the head of a frame, and a block number and a code CRC for error detection of each block are added to block data of a fixed length to form a packet.

Next, the operation in the present embodiment will be described with reference to a case where data is transmitted from data terminal A (communication control device A) to data terminal B (communication control device B) as in the first embodiment. explain. FIG. 7 is a flowchart illustrating the operation of the communication control device on the transmitting side according to the present embodiment. The control flow of the communication control device on the receiving side is the same as in FIG. 4 shown in the first embodiment.

First, when a packet transmission request is generated in the data terminal A (S41), the packet is converted by the communication control device A into the format shown in FIG. 7 (S42, S4).
3) Data for wireless transmission such as a synchronization bit is added by the wireless interface 8 and the communication control device B
Is transmitted to (S44).

The communication control device B on the receiving side performs error detection of each block included in the packet received via the wireless interface 8 by the block assembling unit 7 (S2).
1, 22, 23), and the block that has been normally received is stored in the memory 5 (S24). If there is no error, a reception response is sent to the communication control device A (S25, 26), and
The assembled data is transferred to the memory 5 and transmitted to the data terminal B via the terminal interface 3 (S27). If there is an erroneous block, the block number is included in the retransmission request packet and transmitted to the communication control device A (S25, 28).

Upon receiving the retransmission request (S46, 47, 49), the communication control device A stores the corresponding block in the memory 5 based on the block number contained in the retransmission request packet.
, And the data is transmitted in two consecutive transmissions (S50).

The communication control device B performs error detection of each block included in the packet with respect to the data received via the wireless interface 8 by the block assembling unit 7 (S21, 22, 23), and is continuously transmitted. If there is no error in at least one of the blocks, a reception response is sent to the communication control device A (S25, 26), and the data assembled from the first normally received block and the normally received block by retransmission are stored in the memory 5. The data is transferred and transmitted to the data terminal B via the terminal interface 3 (S27). If there is an erroneous block at the time of retransmission, the block number is included in a retransmission request packet and transmitted to the communication control device A (S25, 28).

Upon receiving the retransmission request (S46, 47, 49), the communication control device A stores the corresponding block in the memory 5 based on the block number contained in the retransmission request packet.
, And the block data is retransmitted and transmitted again (S50), but the retransmission data of this time is transmitted three times (S50). This process is repeated until all of the processes can be received without error, or retransmission is performed up to twice, and the number of consecutive transmissions is increased according to the number of retransmissions, and this procedure is repeated to complete packet transmission.

As described above, according to the present embodiment, 1
By dividing a packet into multiple blocks and retransmitting only the blocks with errors at the time of retransmission and retransmitting, the retransmission data arrival rate is improved, thus reducing the repetition rate of retransmission even in bad line conditions. Can be. As a result, the number of retransmissions and the retransmission time can be relatively reduced, and the throughput and the line utilization efficiency can be improved. Further, since continuous transmission is performed only after a retransmission request is made, and the number of continuous transmissions of block data to be transmitted is increased each time retransmission is performed, it is possible to minimize a decrease in throughput and line use efficiency. it can.

In this embodiment, the number of continuous transmissions is set to N, which is the same as the number of retransmissions. However, the number of continuous transmissions is not always required to be the same, and an appropriate number of continuous transmissions may be used.

Embodiment 3 The present embodiment relates to the communication control device 2 on the reception side and performs data communication with the communication control device on the transmission side shown in the first embodiment. Although the device configuration in the present embodiment is not shown because it is the same as that of the first embodiment, the block assembling unit 7 in the present embodiment further compares the retransmitted block with the erroneous block to block It is provided as block data generating means for generating data. The frame format used in the present embodiment is the same as that in FIG.

FIG. 8 is a flowchart showing the operation of the communication control device on the receiving side which is characteristic in this embodiment. The operation in this embodiment will be described with reference to FIG. The control flow of the communication control device on the transmitting side is the same as that in FIG. 3 shown in the first embodiment. Also in the present embodiment, a case where data is transmitted from data terminal A (communication control device A) to data terminal B (communication control device B) will be described.

First, when a request for transmitting a packet is generated in the data terminal A, the processing is performed in the same manner as in the first embodiment, and the packet is transmitted in the frame format shown in FIG. 2A (S1 to S4).

In the communication control device B, the data received via the radio interface 8
To perform error detection for each block (S61 to S6).
3) If there is no error, a reception response is sent to the communication control device A (S65, 66), and the assembled data is transferred to the memory 5 and transmitted to the data terminal B via the terminal interface 3 (S67). If there is an erroneous block (S68), the block is stored in the memory 5 (S71), and the block number is included in a retransmission request packet and transmitted to the communication control device A (S72).

Upon receiving the retransmission request (S6, 7, 9), the communication control device A reads the corresponding block from the memory 5 based on the block number contained in the retransmission request packet, and It is divided into two sub-blocks (S10), and a block number, a sub-block number, and an error detection code are added to each block number frame according to the above-described rule and transmitted (S11, S11).
4).

In the retransmission data received via the radio interface 8 in the communication control device B, the block assembling unit 7 detects an error in each block (S63). If there is no error, a reception response is sent to the communication control device A (S66), and the assembled data is transferred to the memory 5 and transmitted to the data terminal B via the terminal interface 3 (S67). If there is an erroneous block, the block assembling unit 7 compares the retransmitted block with the erroneous block and generates block data as follows.

First, the bits of the erroneous block data received this time and the previously received erroneous block data stored in the memory 5 are compared. If there is a different bit, the bit of the erroneous block data received this time is inverted, and an error check is performed again (S69). If there is no error, it is determined that the inverted bit string (block) is correct block data, and a reception response is transmitted (S70, 66). And
The data assembled in the normal block is transferred to the memory 5 and transmitted to the data terminal B via the terminal interface 3 (S67). On the other hand, if there is still an error, the block number is put in the retransmission request packet and the communication control device A
Is transmitted again (S72). This procedure is repeated until all data can be received without error, or retransmission is performed twice, and packet transmission is completed.

As described above, according to the present embodiment, the communication control device on the receiving side compares the erroneous data received first and the erroneous data in the retransmission, inverts only the different bits, and reproduces the data. By performing the error detection process, the probability that data can be reproduced even when retransmission data is erroneous increases, and efficient transmission can be performed.

Embodiment 4 The present embodiment relates to the communication control device 2 on the reception side, and performs data communication with the communication control device on the transmission side shown in the second embodiment. Although the device configuration in the present embodiment is not shown because it is the same as that of the second embodiment, the block assembling unit 7 in the present embodiment further compares the retransmitted block with the erroneous block to block It is provided as block data generating means for generating data. The frame format used in the present embodiment is the same as that in FIG.

Next, the operation of this embodiment will be described. The control flow of the communication control device on the transmitting side uses FIG. 6 shown in the second embodiment, and the control flow of the communication control device on the receiving side uses FIG. 8 shown in the third embodiment. Also in the present embodiment, a case where data is transmitted from data terminal A (communication control device A) to data terminal B (communication control device B) will be described.

First, when a packet transmission request is generated in the data terminal A, the processing is performed in the same manner as in the first embodiment, and the packet is transmitted in the frame format shown in FIG. 2A (S41 to S44).

In the communication control device B, the data received via the radio interface 8
To perform error detection for each block (S61 to S6).
3) If there is no error, a reception response is sent to the communication control device A (S65, 66), and the assembled data is transferred to the memory 5 and transmitted to the data terminal B via the terminal interface 3 (S67). If there is an erroneous block (S68), the block is stored in the memory 5 (S71), and the block number is included in a retransmission request packet and transmitted to the communication control device A (S72).

When receiving the retransmission request (S46, 47, 49), the communication control device A stores the corresponding block in the memory 5 based on the block number contained in the retransmission request packet.
, And the data is transmitted in two consecutive transmissions (S50).

In the retransmission data received via the radio interface 8 in the communication control device B, the block assembling unit 7 detects an error in each block (S63). If there is no error, a reception response is sent to the communication control device A (S66), and the assembled data is transferred to the memory 5 and transmitted to the data terminal B via the terminal interface 3 (S67). If there is an erroneous block, the block assembling unit 7 compares the retransmitted block with the erroneous block and generates block data as follows.

First, a majority decision is made on each bit between the previous incorrect block data stored in the memory 5 and the retransmitted data that has been continuously transmitted, and an error check is performed again (S6).
9). If there is no error, it is determined that the bit string (block) determined by majority decision is correct block data, and a reception response is transmitted (S70, 66). Then, the data assembled in the normal block is transferred to the memory 5 and transmitted to the data terminal B via the terminal interface 3 (S67). On the other hand, if there is still an error, the block number is put in the retransmission request packet and transmitted to the communication control device A again (S72). This procedure is repeated until all data can be received without error, or retransmission is performed twice, and packet transmission is completed.

As described above, according to this embodiment, the communication control device on the receiving side makes the majority decision between the erroneous data received first and the erroneous data by retransmission, reproduces the data, and performs error detection. , The probability that data can be reproduced even if retransmission data is incorrect increases, and efficient transmission can be performed.

Embodiment 5 The present embodiment relates to a transmission control device that performs broadcast data communication in packet units and retransmits data in response to a retransmission request from a data receiving terminal. Although the device configuration in the present embodiment is not shown because it is almost the same as that in the first embodiment, the wireless interface 8 serving as the data transmission means in the present embodiment broadcasts the transmission data in a block. Can be. Also, a CP provided as retransmission control means
When a block retransmission request is sent from the data receiving terminal, that is, the communication control device 2 on the receiving side, U4 retransmits only the block data in which the error is detected to only the communication control device 2 that has requested the retransmission. FIG. 9 is a diagram showing a transmission frame format used in the present embodiment.
0 is a diagram illustrating an example of a transmission sequence according to the present embodiment. In FIG. 9, the frame format includes a header, a destination, and a plurality of data blocks. In the example of FIG. 9, the destination is composed of 1-byte data, and is bit-assigned for each data terminal serving as a transmission destination. Of course, it is optional to increase the number of destination bits in order to enable simultaneous broadcast to nine or more terminals. The data transmission destination is designated by setting the bit of the transmission destination terminal to 1. The data block has the same configuration as in each of the above embodiments.

Next, the operation in the present embodiment will be described by taking the configuration shown in FIG. 10 as an example. In FIG.
An example in which broadcast data is transmitted from one base station to terminals 1 to 6 is shown. It is assumed that the base station corresponding to the transmission control device and each terminal corresponding to the reception control device have the same communication control device and control sequence as in the above embodiments.

First, blocks (1) to (1) are transmitted from the base station.
The data up to 0) is transmitted to the terminals 1 to 6 as broadcast data. Each terminal checks the destination of the received data,
If the bit of the own terminal is 1, it is fetched as data addressed to the own terminal and an error check of each data block is performed. If they are all correctly received, ACK is sent, and if there is an error, the erroneous block number is added to the NAK and transmitted to the base station. The reception response is transmitted for each terminal at a predetermined interval. According to FIG.
4 and 6 all receive normally and transmit ACK, but terminal 2 requests retransmission of block numbers (2) and (7), and terminal 3 requests retransmission of block numbers (3) and (7). , Terminal 5
Transmits the transmission requests of the block numbers (3) and (4), respectively. In response to the reception response sent from each terminal, the base station determines whether terminals 2, 3, 5 as destinations for retransmission.
Block (2),
(3), (4), and (7) are broadcast. Note that FIG.
Although this is not shown, if the present embodiment has the same configuration as in Embodiments 1 and 3, the block to be retransmitted is divided into sub-blocks and retransmitted. On the other hand, when the present embodiment has a configuration similar to those of the second and fourth embodiments, blocks to be retransmitted are continuously transmitted and retransmitted.

As described above, according to the present embodiment, at the time of retransmission, broadcast transmission is performed only to the terminal that has requested retransmission, and data transmission is not performed to the terminal that has already received data normally. On the sending side, the number of retransmission destinations is reduced,
In addition, unnecessary ACKs are not received again, and the processing load can be reduced. Unnecessary data is not sent again even to the terminal that has received data normally, so that the processing load can be reduced and the state mismatch between the transmitting side and the receiving side due to unnecessary data retransmission is prevented. can do.

Further, at the time of retransmission, only the blocks to be retransmitted are merged and transmitted only to the terminal that has made the retransmission request, so that the efficiency of data retransmission can be improved.

Embodiment 6 FIG. The present embodiment relates to a communication control system that performs data communication in a packet unit to which a unique packet ID is added. Although the device configuration in the present embodiment is substantially the same as that in the first embodiment, it is not shown. However, in the present embodiment, it is assumed that a packet generating means for adding retransmission count data to a transmission packet is provided on the transmission side. As a feature, this processing is performed by the blocking unit 6 when a transmission block is created. On the receiving side, C provided as retransmission control means is used.
The PU 4 transmits a retransmission request specifying an erroneous block when an error is detected in the same manner as in each of the above embodiments. However, in this embodiment, the PU 4 If data and the same packet as the packet ID of the packet have been normally received, a retransmission request is not transmitted regardless of whether or not the packet has an error.

FIG. 11 is a diagram showing a frame format of transmission data used in the present embodiment. According to FIG. 11, the data format includes a header, a control frame, and a plurality of blocks. The control frame includes the number of retransmissions, destination, packet ID, and C for error detection.
Consists of RC. The retransmission count data described above is set in this retransmission count. Note that each block is the same as in each of the above embodiments, and a description thereof will be omitted.

FIG. 12 is a flowchart showing the operation of the communication control device on the transmitting side in the present embodiment, and FIG. 13 is a flowchart showing the operation of the communication control device on the receiving side in the present embodiment. . The operation of this embodiment will be described with reference to the drawings. In the present embodiment, a case where data is transmitted from data terminal A (communication control device A) to data terminal B (communication control device B) as in Embodiment 1 will be described as an example.

The transmission data from the communication control device A is divided into blocks by the blocking unit 6 (S81, S8).
2) A block number and an error detection code are added to each block (S83), and the number of retransmissions of the control frame is set to 0,
An error detection code is added (S84), a header is added to the head of the packet, and the packet is generated and transmitted (S85). It is assumed that the destination and the packet ID of the control field are added to the transmission data from the data terminal A.

Upon receiving the packet (S101), the communication control device B checks the number of retransmissions of the control frame of the received packet (S102). If the number of retransmissions is 0, it is determined that the data is not retransmission data, and each block is checked for errors as in the conventional method (S104). If there is no error, a reception response is sent to the communication control device A (S106, 107), and the assembled data is stored in the memory 5
To the data terminal B via the terminal interface 3 (S108). Further, in the present embodiment, the packet ID of the packet that can be received normally is stored (S1).
09). Also, if there is an erroneous block,
The block number is included in the retransmission request packet and transmitted to the communication control device A (S106, 110).

Upon receiving the retransmission request (S87, 88, 90), the communication control device A stores the corresponding block in the memory 5 based on the block number contained in the retransmission request packet.
, And a transmission frame is created by the blocking unit 6 (S91). In the present embodiment, the number of retransmissions of the control frame is set to the number of retransmissions, in this case, 1 and then the transmission packet is transmitted (step S91). S92, 85).

The communication control unit B checks the number of retransmissions of the control frame of the received packet (S101, S10).
2). Here, since the number of retransmissions is set to 1, that is, a value other than 0, it can be determined that the packet is retransmission data because the number of retransmissions included in the received packet is not 0. If the number of retransmissions is other than 0, the packet ID is subsequently checked (S10).
3) If the packet ID is the same as the packet ID of the packet normally received in the previous reception processing, the reception response is transmitted without performing the block error check (S111). That is, if the received packet is retransmission data and the same packet as the packet ID of the packet has been normally received, the retransmission request is not transmitted regardless of whether the packet has an error. On the other hand, if the ID is different from the ID of the packet received normally previously, the same processing as the conventional retransmission data is performed (S104 to S110).

When the number of retransmissions is other than 0 and the packet ID is the same as the packet ID of the packet normally received in the previous reception processing, it is considered that the data was successfully received the last time and the reception response was returned. Has been sent,
This is a case where the transmission side retransmits the message because the reception response could not be normally transmitted to the transmission side due to an error or the like. Therefore, according to the present embodiment, when retransmission data is received without a retransmission request, a reception response can be retransmitted to the transmission side and the retransmission data can be discarded at the reception side. Can be prevented from being inconsistent between the transmitting side and the receiving side even if the state is not reached.

Embodiment 7 The present embodiment relates to a communication control system that improves transmission efficiency when data included in a packet is a character. Although the device configuration in the present embodiment is substantially the same as that in the first embodiment, it is not shown. However, in the present embodiment, the CPU 4 provided in the communication control device (transmission control device) on the transmission side is used.
When receiving a retransmission request containing block data in which an error is detected, the received block data containing the error is compared with the stored correct block data corresponding to the block data, and the block data Retransmission control is performed such that only different character data is extracted and transmitted. Further, when an error is detected, the CPU 4 provided in the communication control device (reception control device) on the receiving side performs retransmission control in which the erroneous block data is directly added to the retransmission request and transmitted.

FIG. 14 is a diagram showing a frame format of retransmission data according to the present embodiment. The first transmission data format that is not retransmission is the same as that in FIG. The retransmission data format shown in FIG. 14 includes a header, a block number, a character number to be retransmitted, character data, and an error detection code CRC. Characters having the same block number are transmitted after the block number, and CRC is added to each block as an error detection code from the block number to the last character data of the block.

FIG. 15 is a flowchart showing the operation of the communication control device on the transmitting side in the present embodiment, and FIG. 16 is a flowchart showing the operation of the communication control device on the receiving side in the present embodiment. . The operation of this embodiment will be described with reference to the drawings. In the present embodiment, a case where data is transmitted from data terminal A (communication control device A) to data terminal B (communication control device B) as in Embodiment 1 will be described as an example.

The transmission data from the communication control unit A is divided into blocks by the blocking unit 6 (S121, S12).
2) After a block number and an error detection code are added to each block (S123), a header is added to the head of the packet and transmitted (S124).

Upon receiving the packet (S141), the communication control device B detects an error in each block of the received packet (S142 to 144). If there is no error at all, a reception response is sent out as in the above embodiments (S145 to 147), and the assembled data is transferred to the memory 5 and transmitted to the data terminal B via the terminal interface 3 (S148). . On the other hand, if there is an error, the erroneous block is stored in the memory 5 (S149), and the erroneous block number and data are directly added to the retransmission request packet and transmitted to the communication control device A (S150).

Upon receiving the retransmission request (S126, 127, 129), communication control device A compares the block data added to the retransmission request packet with the block data of the corresponding block number stored in memory 5. Then, an erroneous character is extracted (S130). And FIG.
According to the retransmission data format shown in (1), the character to be retransmitted is retransmitted by adding a block number and a character number (S131, 124). As the character number, for example, the number of the position from the beginning of the block data is used.

Upon receiving the retransmitted data (S141), the communication control device B checks the retransmitted data for errors (S142, 143, 151). The block assembly unit 7
If there is no error in the retransmitted data, the received packet is assembled based on the block data or character data normally received last time. That is, the normally received character is replaced with the data of the error block stored in the memory 5 and stored as a normal block (S152, 153). If the retransmission data is erroneous, erroneous block data is added to the retransmission request again and transmitted (S154). In this way, until the data is normally received or the retransmission is repeated up to four times.

As described above, according to the present embodiment, the amount of retransmitted data can be reduced by configuring retransmitted data only with erroneous characters. As a result, the data error rate can be reduced,
As a result, the transmission time can be reduced, and the transmission efficiency can be improved.

Embodiment 8 FIG. In this embodiment, the HDLC
The present invention relates to a communication control device that performs data communication according to a communication protocol. Although the device configuration in the present embodiment is not shown because it is almost the same as that in the first embodiment,
In the present embodiment, the blocking unit 6 provided in the transmission-side communication control device (transmission control device) is a packet generation unit that generates a packet to which error detection information in the address field and the control field is added. Further, the block assembling unit 7 provided in the communication control device (reception control device) on the receiving side detects an error in the address field and the control field based on the error detection information in the address field and the control field included in the received packet. Error detecting means for performing

FIG. 17 shows an HDLC according to the present embodiment.
FIG. 3 is a diagram illustrating a frame configuration. As shown in FIG. 17A, one frame includes a flag F, an address field A, a control field C, an information field I, a frame check sequence FCS, and a flag F. As shown in FIG. 17B, the information field I is
A frame check sequence ACFCS of an address field A and a control field C is inserted before a set of a plurality of subframes SF and a sub flag FS for partitioning each subframe. Also, one subframe S
F is a sub-sequence number field SN, a sub-information field SI, a sub-frame check sequence SFC
S.

A method for creating one HDLC frame will be described with reference to FIG.

Information transmitted from one data terminal to another data terminal is obtained by dividing a transmission packet transmitted from a data terminal into a plurality of blocks, as in the above-described embodiments, and putting it into a sub information field SI. Further, the subsequence numbers SN are numbered in the order of 0, 1, 2, 3,.... In the subframe check sequence SFCS, a bit string obtained by performing an operation on the SN and SI fields is inserted. Note that H
According to the DLC protocol, the completed subframe S
When five 1s are consecutive in F, a process of inserting 0s is performed next. Then, each SF is partitioned by the sub flag FS. Furthermore, a characteristic process in the present embodiment is
A process of inserting a bit string obtained by performing an operation on the address field A and the control field C into the ACFCS is performed. Thus, the information field I
Is generated. When five 1s are consecutive in the information field I, 0s are inserted following the HDLC protocol. A bit string operated on the fields of the address field A, the control field C, and the information field I is inserted into the frame check sequence FCS, and 5 bits are added to the address field A, the control field C, the information field I, and the frame check sequence FCS. When the number of 1s continues, 0 is inserted after that in the same manner as described above. One frame (packet) is generated before and after this with a flag field interposed. By generating and transmitting such a packet, it is possible to cause the receiving side to check the address field A and the control field C for errors.

On the side receiving this frame, the information field I is extracted by removing the 0 inserted in the reverse procedure,
The error check of the address field A and the control field C is performed by ACFCS. If there is no error, each sub information field is checked, and if there is an error, a retransmission request for an incorrect sub information field is made.

As described above, in the prior art, only error detection for the information field was performed. In the present embodiment, error detection for the address field and the control field is also performed. HDL
Communication control based on the C protocol can be reliably performed. As a result, the error rate in data communication is reduced, and as a result, throughput and line use efficiency can be improved.

In this embodiment, the flag,
The case where data communication is performed in packet units including an address field, a control field, an information field, a frame check sequence, and a flag has been described as applied to communication control based on the HDLC protocol, but communication is performed using a packet including these data. Can be applied to a communication control device based on another protocol.

In each of the above embodiments, a communication control device having both components of the transmission control device and the reception control device according to the present invention has been described as an example, but a transmission only device having only one of the components is described. Alternatively, it is of course possible to configure the device as a reception-only device.

[0106]

[0107]

[0108]

According to the present invention, the reception control device compares the erroneous data received earlier with the erroneous data by retransmission, inverts only the different bits, reproduces the data, and performs error detection. As a result, even if retransmission data is incorrect, the probability that data can be reproduced increases, and efficient transmission can be performed.

[0109]

[0110]

Further, since the packet is transmitted with the number of retransmissions added, it is possible to notify the data receiving side whether or not the data is retransmission data. As a result, on the receiving side, when retransmission data is received even though no retransmission request is made, appropriate measures can be taken, and occurrence of a state mismatch between the transmitting side and the receiving side of the packet can be prevented. .

Further, by configuring the retransmission data only with erroneous characters, the amount of retransmission data can be reduced. As a result, the rate of occurrence of data errors can be reduced, and the line utilization efficiency can be improved.

Further, since error detection of the address field and the control field can be performed, data communication based on normal control data can be reliably performed. As a result, the error rate in data communication is reduced, and as a result, throughput and line use efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a communication control device according to a first embodiment.

FIG. 2 is a diagram showing a frame format of transmission data used in the first embodiment.

FIG. 3 is a flowchart showing an operation of the communication control device on the transmitting side according to the first embodiment.

FIG. 4 is a flowchart showing an operation of the communication control device on the receiving side according to the first embodiment.

FIG. 5 is a diagram showing an example of a transmission sequence according to the first embodiment.

FIG. 6 is a diagram showing a frame format of transmission data according to the second embodiment.

FIG. 7 is a flowchart showing an operation of a communication control device on the transmission side according to the second embodiment.

FIG. 8 is a flowchart showing an operation of the communication control device on the receiving side according to the third embodiment.

FIG. 9 is a diagram showing a frame format of transmission data according to a fifth embodiment.

FIG. 10 is a diagram showing an example of a transmission sequence in the fifth embodiment.

FIG. 11 is a diagram showing a frame format of transmission data according to a sixth embodiment.

FIG. 12 is a flowchart showing an operation of the communication control device on the transmitting side according to the sixth embodiment.

FIG. 13 is a flowchart showing an operation of the communication control device on the receiving side according to the sixth embodiment.

FIG. 14 is a diagram illustrating a frame format of retransmission data according to a seventh embodiment.

FIG. 15 is a flowchart showing an operation of the communication control device on the transmitting side according to the seventh embodiment.

FIG. 16 is a flowchart showing an operation of the communication control device on the receiving side according to the seventh embodiment.

FIG. 17 is a diagram showing an HDLC frame configuration according to the eighth embodiment.

FIG. 18 is a diagram showing an example of a conventional transmission sequence.

FIG. 19 is a diagram showing a data format used in the system shown in FIG. 18;

FIG. 20 is a diagram showing another example of a conventional transmission sequence.

FIG. 21 is a diagram showing an outline of a conventional method of dividing broadcast data into blocks and transmitting the blocks.

FIG. 22 is a diagram showing a frame format of a conventional system in which an information field of the HDLC format is divided into a plurality of subfields.

[Explanation of symbols]

1 data terminal, 2 communication control device, 3 terminal interface, 4 CPU (retransmission control means), 5 memory, 6
Blocking unit (retransmission control unit), 7 block assembling unit (error detecting unit, block data generating unit, packet generating unit), 8 wireless interface (data transmitting unit, data receiving unit), 9 wireless device.

Continuation of front page (56) References JP-A-63-318828 (JP, A) JP-A-63-228838 (JP, A) JP-A-63-109624 (JP, A) JP-A-62-160836 (JP, A) JP-A-62-155639 (JP, A) JP-A-55-120249 (JP, A) JP-A-10-262281 (JP, A) JP-A-9-247132 (JP, A) JP-A-8-195709 (JP, A) JP-A-8-32560 (JP, A) JP-A-6-61981 (JP, A) JP-A-6-21923 (JP, A) JP-A-4-245828 (JP, A A) JP-A-4-111554 (JP, A) JP-A-3-107229 (JP, A) JP-A-1-272333 (JP, A) JP-A-1-252037 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) H04L 1/00 H04L 29/00 H04L 12/00

Claims (4)

(57) [Claims] 1. A reception control device for performing data communication in packet units and having data retransmitted when an error is detected in a received packet, wherein an error detection of a block included in the received packet is performed by a transmitting side. Error detection means for performing based on an error detection code added to each of the blocks , a retransmission control means for transmitting a retransmission request by designating an erroneous block when an error is detected, and A block assembling means for assembling the block thus received as a received packet, and when the transmitting side divides the corresponding block in response to the retransmission request transmitted by the retransmission control means and transmits the divided block, the retransmission block sent from the transmitting side When the error detection means detects an error, according to a comparison result between the retransmitted block and the erroneous block, Block data generating means for generating lock data, wherein the block data generating means compares corresponding bits of the retransmitted block in which the error is detected and the block in which the error is detected, and a different bit exists The block data is generated by inverting the bit of the retransmission block, the error detection unit performs error detection on the block data generated by the block data generation unit, and the block assembling unit performs When no error is detected by the error detection means, a reception packet is assembled from the block data generated by the block data generation means. 2. A communication system comprising: a reception control device that performs character data communication in packet units and transmits a retransmission request when an error is detected in received data; and a transmission control device that retransmits data in response to the retransmission request. In the control system, the transmission control device includes: a blocking unit that divides a transmission packet into a plurality of blocks; a data transmission unit that transmits blocked transmission data; and a retransmission request that includes a block data in which an error is detected. The retransmission control on the transmitting side compares the received block data containing an error with the stored correct block data corresponding to the block data, and extracts and retransmits only different character data from the block data. And a reception unit, wherein the reception control device temporarily stores the received packet. The error detection block contained in the received packet, and error detection means for performing, based on the error detection code added to the respective blocks in the transmitting side, when an error is detected by said error detection means It has a receiving-side retransmission control means for directly sending the additional to the block data for which the the error to the retransmission request, and a block assembly means for assembling the received packet based on correctly received block data or character data, The block data to be retransmitted is
The communication control system characterized in that it constitutes at only. 3. A communication control system having a communication control device for performing data communication in packet units, a data transmission step of transmitting a transmission packet by dividing the transmission packet into a plurality of blocks in a transmission-side communication control device; When an error is detected in the block received at the transmitting side based on the error detection code added to each block on the transmitting side, a retransmission requesting step of specifying a block in which the error is detected and requesting a retransmission, A retransmission step in which only the block in which the error is detected is further divided into a plurality of blocks and retransmitted in the communication control device on the side, and an error is detected in the retransmission block sent from the communication control device on the reception side in the communication control device on the reception side. Is detected, each corresponding block between the retransmitted block and the block in which the error is detected. A block data generating step of generating block data by inverting the bit of the retransmission block when different bits are present, and performing error detection on the block data generated by the block data generating step. An error detecting step to be performed, and a block assembling step of assembling a received packet with the block data generated by the block data generating step when no error is detected by the error detecting step, A communication control method, wherein correct block data is automatically generated in a device. 4. A communication control system having a communication control device for performing character data communication in packet units, a data transmission step of transmitting a transmission packet by dividing the transmission packet into a plurality of blocks in a transmission-side communication control device, to the received packet in the apparatus, when an error is detected based on the added error detection code to each block, a retransmission request step in which the error is directly added to the retransmission request by the block data detected, the transmission A retransmission that compares the block data included in the retransmission request received by the side communication control device with the stored correct block data corresponding to the block data, and extracts and retransmits only different character data from the block data. Step, and the reception side communication control device normally receives Communication control method, which comprises a block assembly steps for assembling the received packet is already based on the block data being received and Yarakutadeta, the.