JPH11186994A - Method and system for arq communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication method where error correction for a reception sequence number is attained through the addition of a forward error correction(FEC) code, and the reception sequence number is checked before a CRC error check so as to make a quick retransmission request. SOLUTION: An ARQ communication method employs a communication packet consisting of an opening flag, a transmission sequence number, an FED mis-correction code for the transmission sequence number, data and a cyclic redundancy check error code and an ending flag to conduct communication. This method has a reception sequence number output step (S3) that outputs a corrected reception sequence number through the use of FED error correction code for the transmission sequence number in the case of detecting an error in the reception sequence number, a continuity confirmation steppe (S4) for confirming the continuity of the reception sequence number, and a retransmission request issuance step (S5) for issuing a retransmission request as a transmitted retransmission request, when a non-consecutive error is detected in the continuity confirmations step.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an error correction method for performing communication using ARQ (Automatic Repeat Request) as an error correction method in communication having a high transmission line error rate such as wireless communication such as PHS. The present invention relates to an ARQ communication device using the error correction method.

[0002]

2. Description of the Related Art In recent years, second generation mobile communication systems featuring digital communication have been rapidly spreading. For example, P
HS (Personal Handy Phone System) is TDMA / T
DD (Time Division Multiplex Access / Time Division
Duplex) system and 32 kbps transmission capacity in one slot, so it can transmit not only voice, data, and still images but also video, making it a great infrastructure for realizing mobile multimedia communications. Expected.

[0003] A conventional ARQ communication method and ARQ communication apparatus will be described with reference to FIGS. 6, 7, 8, 9, 10 and 11. FIG. 6 is a format diagram showing a format of a sequence number field, FIG. 7 is a timing diagram showing a packet structure in a conventional ARQ communication method and a sequence number error detection timing for occurrence of a transmission path error, and FIGS. FIG. 10 is a block diagram showing a conventional ARQ communication apparatus to which the ARQ communication method is applied, FIG. 10 is a timing chart showing sequence number error detection timing for occurrence of a random error in the conventional ARQ communication method, and FIG.
5 is a flowchart illustrating an RQ communication method.

In FIG. 6, SN is a sequence number, P
T is the payload type. 8 and 9, 1 is a switch, 2 is a switch switching determining unit, 3 is a switch, 4 is a transmission sequence number counter, 5 is a switch,
6 is a transmission data amount measurement unit, 7 is an error detection code calculation unit, 8
Is a multiplexing unit, 9 is a packet size determination unit, 10 is a baseband processing unit, 11 is an RF module, 12 is a demultiplexing unit, 13 is an error detection code operation unit, 14 is a switch, 15
Is an error detection code comparator, 16 is a reception sequence number counter,
17 is a retransmission sequence number storage memory, 18 is a retransmission data storage memory, 19 is a reception sequence number comparator, 20 is a switch, 21 is a switch, and 22 is a data type identification unit.

First, a conventional ARQ will be described with reference to FIGS.
(Automatic Repeat Request) A communication method will be described.

[0006] As an explanation of terms, the primary station is a station to which data is to be transmitted, and the secondary station is a station that receives data from the primary station and returns a response.

The operation of the ARQ communication apparatus to which the conventional ARQ communication method shown in FIGS. 8 and 9 is applied when no error occurs on the communication network will be described. At this time, in the primary station, retransmission data and a retransmission request message to be transmitted have not been input to the switch 1, and the switch switching determination unit 2 outputs a switch switching signal a that switches the switch 1 to output transmission data. Further, the switch switching determining unit 2 outputs a switch switching signal b that switches so that the switch 3 is turned on and a switch switching signal c that switches so that the switch 5 outputs the transmission sequence number counter output value. The switch 1 switches based on a switch switching signal a. The transmission data passes through the switch 1 and is input to the switch 3, the retransmission data storage memory 18, the transmission data amount measurement unit 6, the error detection code calculation unit 7, and the multiplexing unit 8 as the selected transmission data. The switch 3 switches based on a switch switching signal b. The selected transmission data passes through the switch 3 and is input to the transmission sequence number counter 4. The transmission sequence number counter 4 counts up the transmission sequence number by one each time transmission data selected by the input packet size value is input, and outputs it as a transmission sequence number counter output value. The switch 5 switches based on the switch switching signal c, and outputs a transmission sequence number counter output value as a transmission sequence number. Retransmission data storage memory 18
Holds the selected transmission data. The transmission data amount measuring unit 6 measures the data amount of the input transmission data and outputs the transmission data amount. The packet size determining unit 9 determines the packet size based on the amount of transmission data and the presence or absence of the received retransmission request, and outputs the packet size. The error detection code operation unit 7 calculates an error detection code (CRC code) of the selected transmission data and transmission sequence number, and outputs an error detection code (CRC code). The multiplexing unit 8 selects the transmission data based on the input packet size,
The transmission sequence number and the error detection code (CRC code) are multiplexed and output as transmission multiplexed data. The transmission multiplexed data is converted to baseband data by the baseband processing unit 10 and converted to radio waves by the RF module 11.

[0008] The radio wave received by the secondary station is converted into baseband data by the RF module 11 and is converted into reception data by the baseband processing unit 10. The received multiplexed data is input to the demultiplexing unit 12, and is demultiplexed into received data, a received error detection code (CRC code), and a reception sequence number. The reception data and the reception sequence number are input to the error detection code operation unit 13. The received data is also input to the switch 14. The error detection code calculation unit 13 calculates an error detection code (CRC code) for the received data and the reception sequence number, and outputs an error detection code (CRC code) calculation result. The error detection code comparator 15 compares the received error detection code (CRC code) with the calculation result of the error detection code (CRC code), and when they match, the error detection code comparator 15 determines that no error has been detected as an error detection signal. Output. At this time, the switch 14 is turned on, and the switch 14 outputs received data. The received data is input to the data type identification unit 22 and the switch 21. The data type identification unit 22 identifies whether the input received data is a command such as a retransmission request or normal communication data using a PT (payload type) in a sequence number field, and switches the switch 21 based on the PT. .

FIG. 6 shows a sequence number field format. PT (payload type) is 1-bit information, and when "0" indicates that received data is a command, and when "1", indicates that received data is normal communication data. If the received data is a command such as a retransmission request, the switch 21 switches to the upper side. If the received data is normal communication data, the switch 21 switches to the lower side. Here, the switch 21 switches to the lower side, and the received data passes through the switch 21 and is input to the switch 20. Only when error non-detection is output as an error detection signal from the error detection code comparator 15 and non-command data is output from the data type identification unit 22, the reception sequence number comparator 1
9 operates, and if the reception sequence number output from the demultiplexing unit 12 and the output value of the reception sequence number counter output from the reception sequence number counter 16 match, it is determined that data has been successfully received, and The sequence number comparator 19 outputs a non-retransmission request as a retransmission request to be transmitted. At this time, the switch 20 is turned on, and the switch 20 outputs received data. At the same time, a non-retransmission request is input to the reception sequence number counter 16 as a retransmission request to be transmitted, and the reception sequence number is counted up by one.

The operation of the conventional ARQ communication apparatus to which the conventional ARQ communication method shown in FIGS. 8 and 9 is applied when an error occurs on a communication network will be described. In the receiving operation of the secondary station, the error detection code comparator 15 compares the received error detection code (CRC code) with the operation result of the error detection code (CRC code). Reference numeral 15 outputs error detection as an error detection signal. When error detection is input as an error detection signal, the switch 14 is turned off, and the received data at this time is discarded. At the same time, when error detection is input as an error detection signal, the reception sequence number comparator 19 does not operate. As described above, during error detection, the received data is simply discarded, and no retransmission request or the like is performed.

When a transition is made from the error detecting state to the error-free state, a retransmission request is issued as follows.

The error detection code comparator 15 compares the received error detection code (CRC code) with the operation result of the error detection code (CRC code), and if they match, the error detection code comparator 15 outputs an error detection signal as an error detection signal. Output non-detection. At this time, the switch 14 is turned on, and the switch 14 outputs received data. The received data is a data type identification unit 2
2 is input to the switch 21. Data type identification unit 22
Indicates whether the input received data is a command such as a retransmission request or normal communication data in the sequence number field.
Identification is performed using T (payload type), and the switch 21 is switched based on the identification.

FIG. 6 shows the sequence number field format. PT (payload type) is 1-bit information, and when "0" indicates that received data is a command, and when "1", indicates that received data is normal communication data. If the received data is a command such as a retransmission request, the switch 21 switches to the upper side. If the received data is normal communication data, the switch 21 switches to the lower side. Here, the switch 21 switches to the lower side, and the received data passes through the switch 21 and is input to the switch 20. Only when error non-detection is output as an error detection signal from the error detection code comparator 15 and non-command data is output from the data type identification unit 22, the reception sequence number comparator 19 operates and the demultiplexing unit 12 Is compared with the output value of the reception sequence number counter output from the reception sequence number counter 16. At this time, since the previous data has been discarded due to an error, the comparison result does not match, and the reception sequence number comparator 19 outputs a retransmission request as a retransmission request to be transmitted. The switch 20 is turned off, and the received data at this time is discarded. The retransmission request as the retransmission request to be transmitted is input to the reception sequence number counter 16, but the reception sequence number counter 16 at the time of the retransmission request does not count up. A retransmission request as a retransmission request to be transmitted is also input to the switch 1 and the switch switching determination unit 2. At this time, the switch switching determination unit 2 includes a switch switching signal a for switching to output the retransmission request transmitted by the switch 1, a switch switching signal b for switching the switch 3 to be turned off, and a reception sequence number counter. A switch switching signal c that switches to output an output value is output. The switch 1 switches based on a switch switching signal a. The retransmission request to be transmitted passes through the switch 1 and is input to the switch 3, the retransmission data storage memory 18, the transmission data amount measurement unit 6, the error detection code calculation unit 7, and the multiplexing unit 8 as selected transmission data. The switch 3 switches based on the switch switching signal b, and is turned off here. The switch 5 switches based on the switch switching signal c, and outputs the output value of the reception sequence number counter as the transmission sequence number.
The transmission data amount measuring unit 6 measures the data amount of the input transmission data and outputs the transmission data amount. The packet size determining unit 9 determines the packet size based on the amount of transmission data and the presence or absence of the received retransmission request, and outputs the packet size. The error detection code calculation unit 7 calculates an error detection code (CRC code) of the selected transmission data and transmission sequence number, and outputs an error detection code (CRC code). The multiplexing unit 8 selects the transmission data, the transmission sequence number, and the error detection code (C) based on the input packet size.
(RC code) are multiplexed and output as transmission multiplexed data. The transmission multiplexed data is converted to baseband data by the baseband processing unit 10 and converted to radio waves by the RF module 11.

In this way, a retransmission request is transmitted from the secondary station to the primary station. The radio wave received at the primary station is R
The data is converted to baseband data by the F module 11 and converted to received data by the baseband processing unit 10. The reception multiplexed data is input to the demultiplexing unit 12, and the reception data,
The received error detection code (CRC code) is separated into a reception sequence number. The reception data and the reception sequence number are input to the error detection code operation unit 13. Receive data is switch 1
4 is also input. The error detection code calculation unit 13 calculates an error detection code (CRC code) for the received data and the reception sequence number, and outputs an error detection code (CRC code) calculation result. The error detection code comparator 15 compares the received error detection code (CRC code) operation result with the error detection code (CRC code) calculation result, and when they match, the error detection code comparator 1
5 outputs an error non-detection as an error detection signal. At this time, the switch 14 is turned on, and the switch 14 outputs received data. The received data is a data type identification unit 2
2 is input to the switch 21. Data type identification unit 22
Indicates whether the input received data is a command such as a retransmission request or normal communication data in the sequence number field.
Identification is performed using T (payload type), and the switch 21 is switched based on the identification.

FIG. 6 shows the sequence number field format. PT (payload type) is 1-bit information, and when "0" indicates that received data is a command, and when "1", indicates that received data is normal communication data. If the received data is a command such as a retransmission request, the switch 21 switches to the upper side. If the received data is normal communication data, the switch 21 switches to the lower side. Here, the switch 21 switches to the upper side, and the received retransmission request is input to the retransmission data storage memory 18, the retransmission sequence number storage memory 17, and the packet size determination unit 9. Although error non-detection is output from the error detection code comparator 15 as an error detection signal, the reception sequence number comparator 19 does not operate because the data type identification unit 22 identifies the command data. Therefore, the switch 20 is off. When the received retransmission request is input to the retransmission sequence number storage memory 17, retransmission data corresponding to the input reception sequence number at this time is output from the retransmission data storage memory 18. Thus, the retransmission sequence number storage memory 1
7 and the retransmission data storage memory 18 are linked one-to-one. The retransmission data is input to the switch switching determination unit 2. When retransmission data is input to the switch switching determining unit 2, the switch switching determining unit 2 switches the switch 1 so that the switch 1 outputs the retransmitted data, the switch switching signal a that switches the switch 3 off, and the switch switching. A signal b and a switch switching signal c for switching the switch 5 so as to output a reception sequence number counter output value are output. The switch 1 switches based on a switch switching signal a. The retransmission data passes through the switch 1 and is input to the switch 3, the retransmission data storage memory 18, the transmission data amount measurement unit 6, the error detection code operation unit 7, and the multiplexing unit 8 as selected transmission data. The switch 3 switches based on a switch switching signal b.
The selected transmission data cannot pass through the switch 3, and the transmission sequence number counter 4 does not operate. The switch 5 switches based on the switch switching signal c, and outputs the output value of the reception sequence number counter as the transmission sequence number. The retransmission data storage memory 18 does not perform a rewriting operation. The transmission data amount measuring unit 6 measures the data amount of the input transmission data and outputs the transmission data amount. The packet size determining unit 9 determines the packet size based on the amount of transmission data and the presence or absence of the received retransmission request, and outputs the packet size. The error detection code calculation unit 7 calculates an error detection code (CRC code) of the selected transmission data and transmission sequence number, and outputs an error detection code (CRC code). The multiplexing unit 8 multiplexes the selected transmission data, transmission sequence number, and error detection code (CRC code) based on the input packet size, and outputs the multiplexed data as transmission multiplexed data. The transmission multiplexed data is transmitted to the baseband processing unit 1
0 and converted to baseband data, RF module 1
It is converted into a radio wave by 1.

In this way, the response data to the retransmission request is transmitted from the primary station to the secondary station. The response data is received by the secondary station, and the same receiving operation as in the state where no error occurs on the communication network is performed, and the state transits to the normal communication state.

The structure of a communication packet in such a conventional ARQ communication method will be described with reference to FIG. The communication packet is configured to be sandwiched between an opening flag (Op flag) and an ending flag (Ed flag). In the meantime, the sequence number N (S), data, CRC (Cy
clic Redundancy Checking).
The opening flag is used to identify the start of the packet, and the ending flag is used to identify the end of the packet. The sequence number N (S) is used for transmitting to the receiving side what number packet the transmitting side is transmitting at the time of transmission, and at the time of receiving, for confirming that double capture and packet dropout do not occur at the receiving side. Used. The data stores communication data to be transmitted or a command such as a retransmission request. CRC (Cyclic Redundancy Checki
ng) The error detection code uses the sequence number N (S) and the remainder obtained by dividing the data by the generator polynomial.

Next, the timing for detecting a sequence number error (a discontinuous sequence number error) when a transmission line error occurs will be described with reference to FIG. When a transmission path error occurs as shown in FIG. 7, either an operation of detecting a packet during the occurrence of the transmission path error or discarding the packet due to a CRC error is performed.
Thereafter, when one or more packets have no transmission path error, the CRC error check and the sequence number error check are performed from the time when the ending flag of the received packet is recognized, and then the sequence number error is performed for the first time. (Discontinuous error) can be detected. Therefore, the timing for detecting the sequence number error (non-continuous error) is as shown in FIG.

Finally, the above-described conventional ARQ communication method will be described with reference to the flowchart of the ARQ communication method shown in FIG. FIG. 11 mainly shows the flow on the secondary station side. The receiving side first starts detection of an opening flag (S11). After detecting the opening flag, detection of the ending flag is started (S12).
The data received during this time is temporarily stored in a memory or the like.
The packet size is determined by detecting the ending flag. The CRC error of the packet is checked using the CRC error detection code added at the end of the packet (S13). If a CRC error is detected, it is determined that there is an error in the received data, the received data is discarded (S14), and an opening flag detection wait is performed to receive the next packet. If no CRC error is detected, it is determined that there is no error in the received data, and the sequence number is checked (S15). If the sequence number received this time is a continuous value with the sequence number received normally immediately before, it is determined that the data has been received in the correct order and the received data is stored (S16). If the sequence number received this time is a discontinuous value with the sequence number received normally immediately before, it is determined that double capture or packet dropout has occurred, and a retransmission request is issued to the primary station (S17). . Then, the received data is discarded, and the reception of the opening packet is awaited to receive the next packet.

In the ARQ (Auomatic Repeat Request) communication method, error detection and retransmission request have been made in this manner.

[0021]

However, in the conventional ARQ communication method and the conventional ARQ communication apparatus, as shown in FIG. 10, the error occurrence period is short, but when the error occurs frequently, the error occurrence period is particularly terminated. If the error-free period from the start to the next error occurrence period is shorter than the packet size, the CRC error continues to be detected.
It takes time until a packet without an RC error can be received. For this reason, the timing of checking the sequence number is delayed, so that there is a problem that it takes time from when an error occurs to when a retransmission request is transmitted. This leads to an increase in retransmission delay, and a decrease in real-time performance when communicating multimedia data such as video and audio.

In the ARQ communication method and the ARQ communication device, it is required that the time from the occurrence of an error to the transmission of a retransmission request be reduced to prevent an increase in retransmission delay.

The present invention provides an FEC (Forword Error Correc)
Option) Addition of a code to enable error correction of the reception sequence number, check the reception sequence number prior to the CRC error check, and add an ARQ communication method and an FEC code to request retransmission earlier. Accordingly, it is an object of the present invention to provide an ARQ communication device that enables error correction of a reception sequence number, checks a reception sequence number prior to a CRC error check, and makes a retransmission request earlier.

[0024]

In order to solve this problem, an ARQ communication method according to the present invention comprises an opening flag, a transmission sequence number, a transmission sequence number FEC error correction code, data, a CRC error detection code, and an ending flag. An ARQ communication method for performing communication using a configured communication packet, wherein when an error in a reception sequence number is detected, the error is corrected using a transmission sequence number FEC error correction code, and the corrected reception sequence number is used. Receiving step for outputting a reception sequence number, a continuity check step for checking the continuity of the reception sequence number, and a retransmission request issuance as a retransmission request to be transmitted when a non-continuous error is detected in the continuity check step And a configuration having steps.

Thus, an ARQ communication method for enabling error correction of the reception sequence number by adding the FEC code, checking the reception sequence number prior to the CRC error check, and issuing a retransmission request sooner is obtained. .

The ARQ of the present invention for solving this problem
The communication device is an ARQ communication device that performs communication using a communication packet including an opening flag, a transmission sequence number, a transmission sequence number FEC error correction code, data, a CRC error detection code, and an ending flag. An error correction code operation unit for generating an FEC error correction code for a number, a multiplexing unit for multiplexing a transmission sequence number and an FEC error correction code for transmission sequence number, data, and a CRC error detection code; a transmission sequence number and a transmission order A demultiplexing unit that separates the number FEC error correction code, data, and CRC error detection code, a reception sequence number counter that counts when a retransmission request to be transmitted is a non-retransmission request, and a reception sequence number error that is detected. Performs correction using the FEC error correction code for the transmission sequence number, outputs the corrected reception sequence number, If no error is detected, the error correction unit outputs the reception sequence number as a corrected reception sequence number, and the corrected reception sequence number output from the error correction unit and the reception sequence number output from the reception sequence number counter. When the output value of the reception sequence number counter does not match, a reception sequence number comparator that outputs a retransmission request as a retransmission request to be transmitted is provided.

Thus, an ARQ communication apparatus which enables error correction of a reception sequence number by adding an FEC code, and which checks a reception sequence number prior to a CRC error check and makes a retransmission request earlier. Is obtained.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises an opening flag, a transmission sequence number, a transmission sequence number FEC error correction code, data, a CRC error detection code,
An ARQ communication method for performing communication using a communication packet including an ending flag, wherein when an error in a reception sequence number is detected, the error is corrected using a transmission sequence number FEC error correction code, and the error is corrected. A receiving sequence number output step for outputting as a receiving sequence number, a continuity check step for checking continuity of the receiving sequence number, and a retransmission request is issued as a retransmission request to be transmitted when a discontinuity error is detected in the continuity checking step. A retransmission request issuance step, which enables error correction of the reception sequence number, enables the reception sequence number to be checked prior to the CRC error check, and A retransmission request is issued as a retransmission request to be transmitted, which has the effect of reducing retransmission delay.

According to a second aspect of the present invention, there is provided an ARQ for performing communication using a communication packet including an opening flag, a transmission sequence number, a transmission sequence number FEC error correction code, data, a CRC error detection code, and an ending flag.
What is claimed is: 1. A communication apparatus, comprising: an error correction code operation unit that generates a transmission sequence number FEC error correction code; and a multiplexing unit that multiplexes a transmission sequence number, a transmission sequence number FEC error correction code, data, and a CRC error detection code. A demultiplexing unit for separating a transmission sequence number, a transmission sequence number FEC error correction code, data, and a CRC error detection code; a reception sequence number counter for counting a case where a retransmission request to be transmitted is a non-retransmission request; If a number error is detected, the error is corrected using the FEC error correction code for the transmission sequence number and output as a corrected reception sequence number. If no error is detected in the reception sequence number, the reception sequence number is corrected. Error correction unit that outputs as is the corrected reception sequence number, and the corrected reception sequence number output from the error correction unit and the output from the reception sequence number counter And a reception sequence number comparator that outputs a retransmission request as a retransmission request to be transmitted when the output value of the received reception sequence number counter does not match, thereby enabling error correction of the reception sequence number. , CR
It is possible to check the reception sequence number prior to the C error check, and when a non-consecutive error is detected, a retransmission request is issued as a retransmission request to be transmitted, which has the effect of reducing retransmission delay.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a diagram showing an embodiment A according to Embodiment 1 of the present invention.
FIG. 2 is a timing chart showing a packet structure in the RQ communication method and a sequence number error detection timing for transmission line error occurrence. FIGS. 2 and 3 show an ARQ communication apparatus to which the ARQ communication method according to the first embodiment of the present invention is applied. FIG. 4 is a block diagram, FIG. 4 is a timing chart showing a sequence number error detection timing for occurrence of a random error in the ARQ communication method according to the first embodiment of the present invention, and FIG. 5 is for explaining the ARQ communication method according to the first embodiment of the present invention. It is a flowchart of FIG.

2 and 3, reference numeral 23 denotes a switch,
4 is a switch changeover determination unit, 25 is a switch, 26 is a transmission sequence number counter, 27 is a switch, 28 is a transmission data amount measurement unit, 29 is an error detection code calculation unit, 30 is a multiplexing unit, and 31 is a packet size determination unit. , 32 are a baseband processing unit, 33 is an RF module, 34 is a demultiplexing unit, 3
5 is an error detection code operation unit, 36 is a switch, 37 is an error detection code comparator, 38 is a reception sequence number counter, 39 is a retransmission sequence number storage memory, 40 is a retransmission data storage memory, and 41 is a reception sequence number comparison. Container, 42 is a switch, 4
3 is a switch, 44 is a data type identification unit, 45 is an error correction code operation unit, and 46 is an error correction unit. Components 23 to 44 in FIGS. 2 and 3 correspond to components 1 to 22 in FIGS. 8 and 9. That is, the ARQ communication device shown in FIGS. 2 and 3 differs from the ARQ communication device shown in FIGS. 8 and 9 in that an ARQ communication device 45 and an error correction unit 46 are provided.

First, an ARQ communication method according to the present embodiment will be described with reference to FIGS. As described above, as described above, the primary station is a station that attempts to transmit data, and the secondary station is a station that receives data from the primary station and returns a response.

The operation of the ARQ communication apparatus shown in FIGS. 2 and 3 to which the ARQ communication method according to the present embodiment is applied when no error occurs on the communication network will be described. At this time, in the primary station, retransmission data and a retransmission request message to be transmitted have not been input to the switch 23, and the switch switching determination unit 24 outputs a switch switching signal a that switches the switch 1 to output transmission data. The switch changeover determination unit 24 includes a switch 25
Switch signal b that switches to turn on
And a switch switching signal c for switching the switch 27 so as to output the transmission sequence number counter output value. The switch 23 switches based on the switch switching signal a. The transmission data passes through the switch 23 and is input to the switch 25, the retransmission data storage memory 40, the transmission data amount measurement unit 28, the error detection code calculation unit 29, and the multiplexing unit 30 as the selected transmission data. Switch 2
5 is switched based on the switch signal b. The selected transmission data passes through the switch 25 and is input to the transmission sequence number counter 26. The transmission sequence number counter 26 counts up the transmission sequence number by one each time the transmission data selected by the input packet size value is input and outputs it as a transmission sequence number counter output value. The switch 27 switches based on the switch switching signal c, and outputs the output value of the transmission sequence number counter as the transmission sequence number. The retransmission data storage memory 40 holds the selected transmission data. Transmission data amount measurement unit 28
Measures the amount of input transmission data and outputs the amount of transmission data. The packet size determining unit 31 determines the packet size based on the amount of transmission data and the presence or absence of the received retransmission request, and outputs the packet size. The error correction code operation unit 45 outputs the error correction code (FEC) of the transmission sequence number.
Code) and outputs an error correction code (FEC code). The error detection code operation unit 29 performs an error detection code (CRC) process on the selected transmission data, the error detection code (CRC code) and the error correction code (FEC code) of the transmission sequence number.
C code) and outputs the result. The multiplexing unit 30 multiplexes the selected transmission data, transmission sequence number, error detection code (CRC code) and error correction code (FEC code) based on the input packet size, and outputs the multiplexed data as transmission multiplexed data. I do. The transmission multiplexed data is converted into baseband data by the baseband processing unit 32 and is converted into radio waves by the RF module 33.

Radio waves received by the secondary station are converted into baseband data by the RF module 33 and converted into received data by the baseband processing unit 32. The received multiplexed data is input to the demultiplexing unit 34 and demultiplexed into received data, a received error detection code (CRC code), a reception sequence number, and a received error correction code (FEC code). The reception sequence number and the error correction code (FEC code) are
6 is input. If an error in the reception sequence number is detected, the error correction unit 46 corrects the error using an error correction code (FEC code), outputs the corrected reception sequence number, and if no error is detected in the reception sequence number. , And outputs the reception order number as it is as the corrected reception order number. Only when non-command data is output from the data type identification unit 44, the reception sequence number comparator 41 operates and is output from the corrected reception sequence number output from the error correction unit 46 and the reception sequence number counter 38. If the output value of the reception sequence number counter matches, it is determined that data has been normally received, and the reception sequence number comparator 41 outputs a retransmission non-request as a retransmission request to be transmitted. The reception data, the reception sequence number, and the error correction code (FEC code) are input to the error detection code operation unit 35. The received data is also input to the switch 36. The error detection code operation unit 35 includes:
An error detection code (CRC code) is calculated for the received data, reception sequence number, and error correction code (FEC code), and an error detection code (CRC code) calculation result is output. The error detection code comparator 37 compares the received error detection code (CRC code) with the operation result of the error detection code (CRC code), and if they match, the error detection code comparator 37 outputs an error non-detection signal as an error detection signal. Is output. At this time, switch 3
6 is turned on, and the switch 36 outputs the received data. The received data is transmitted to the data type identification unit 44 and the switch 4
3 is input. The data type identification unit 44 identifies whether the input received data is a command such as a retransmission request or normal communication data by using a PT (payload type) of a sequence number field, and based on the identification, determines whether the switch 4
Switch 3.

FIG. 6 shows the sequence number field format. PT (payload type) is 1-bit information, and when "0" indicates that received data is a command, and when "1", indicates that received data is normal communication data. If the received data is a command such as a retransmission request, the switch 43 switches to the upper side. If the received data is normal communication data, the switch 43 switches to the lower side. Here, the switch 43 switches to the lower side, and the received data passes through the switch 43 and is input to the switch 42. The switch 42 is turned on because a non-retransmission request is input as a retransmission request to be transmitted, and the switch 42 outputs received data. At the same time, a retransmission non-request is input to the reception sequence number counter 38 as a retransmission request to be transmitted, and the reception sequence number is counted up by one.

The operation of the ARQ communication apparatus shown in FIGS. 2 and 3 when an error occurs on the communication network will be described. In the reception operation of the secondary station, the reception sequence number comparator 41 determines whether the corrected reception sequence number output from the error correction unit 46 and the reception sequence number counter output value output from the reception sequence number counter 38 do not match. If it is determined that the data has not been received normally, the reception sequence number comparator 41
A retransmission request is output as a retransmission request to be transmitted. The switch 42 is turned off because the retransmission request is input as the retransmission request to be transmitted, and the received data at this time is discarded. The retransmission request as a retransmission request to be transmitted is input to the reception sequence number counter 38, but the reception sequence number counter 38 does not count up at the time of the retransmission request. The retransmission request as a retransmission request to be transmitted is also input to the switch 23 and the switch switching determination unit 24. At this time, the switch switching determination unit 24 includes a switch switching signal a for switching to output the retransmission request transmitted by the switch 23, a switch switching signal b for switching the switch 25 to be off, and a reception sequence number counter. A switch switching signal c that switches to output an output value is output. The switch 23 switches based on the switch switching signal a. The retransmission request to be transmitted passes through the switch 23 and is input to the switch 25, the retransmission data storage memory 40, the transmission data amount measuring unit 28, the error detection code calculating unit 29, and the multiplexing unit 30 as selected transmission data. The switch 25 switches based on the switch switching signal b, and is turned off here. Switch 2
7 is switched based on the switch signal c, and outputs the output value of the reception sequence number counter as the transmission sequence number. The transmission data amount measuring unit 6 measures the data amount of the input transmission data and outputs the transmission data amount. The packet size determining unit 31 determines the packet size based on the amount of transmission data and the presence or absence of the received retransmission request, and outputs the packet size. The error correction code operation unit 45 calculates an error correction code (FEC code) of the transmission sequence number and outputs an error correction code (FEC code). Error detection code operation unit 29
Calculates an error detection code (CRC code) for the selected transmission data, transmission sequence number, and error correction code (FEC code), and outputs an error detection code (CRC code). The multiplexing unit 30 multiplexes the selected transmission data, transmission sequence number, error detection code (CRC code) and error correction code (FEC code) based on the input packet size, and outputs the multiplexed data as transmission multiplexed data. I do. The transmission multiplexed data is converted into baseband data by the baseband processing unit 32 and is converted into radio waves by the RF module 33.

In this way, a retransmission request is transmitted from the secondary station to the primary station. The radio wave received at the primary station is R
The data is converted into baseband data by the F module 33, and is converted into reception data by the baseband processing unit 32. The received multiplexed data is input to the demultiplexing unit 34,
The received error detection code (CRC code), error correction code (FEC code) and reception sequence number are separated. The reception sequence number and the error correction code (FEC code) are input to the error correction unit 46. If an error in the reception sequence number is detected, the error correction unit 46 corrects the error using an error correction code (FEC code), outputs the corrected reception sequence number, and if no error is detected in the reception sequence number. , And outputs the reception order number as it is as the corrected reception order number. Only when non-command data is output from the data type identification unit 44, the reception order number comparator 41 operates and does not operate here. The received data here is a retransmission request command. The reception data, the reception sequence number, and the error correction code are input to the error detection code operation unit 35. The received data is also input to the switch 36. The error detection code calculation unit 35 calculates an error detection code (CRC code) for the received data, the reception sequence number, and the error correction code, and outputs an error detection code (CRC code) calculation result. The error detection code comparator 37 compares the received error detection code (CRC code) with the operation result of the error detection code (CRC code), and if they match, the error detection code comparator 37 determines that no error has been detected as an error detection signal. Output. At this time, switch 3
6 is turned on, and the switch 36 outputs the received data. The received data is transmitted to the data type identification unit 44 and the switch 4
3 is input.

The data type identification section 44 identifies whether the input received data is a command such as a retransmission request or normal communication data, and switches the switch 43 based on this. If the received data is a command such as a retransmission request, the switch 43 switches to the upper side. If the received data is normal communication data, the switch 43 switches to the lower side. Here, the switch 43 is switched to the upper side, and the received retransmission request is input to the retransmission data storage memory 40, the retransmission sequence number storage memory 39, and the packet size determination unit 31.
Error non-detection is output from the error detection code comparator 37 as an error detection signal, and the reception order number comparator 41 does not operate because the data type identification unit 44 identifies the command data. Therefore, the switch 42 is off. When the received retransmission request is input to the retransmission sequence number storage memory 39, the retransmission data corresponding to the input reception sequence number at this time is output from the retransmission data storage memory 40. Thus, the retransmission sequence number storage memory 39 and the retransmission data storage memory 40 are linked one-to-one. The retransmission data is input to the switch switching determination unit 24.
When the retransmission data is input to the switch switching determining unit 24, the switch switching determining unit 24 switches the switch 23 so that the switch 23 outputs the retransmitted data, and the switch switching that switches the switch 25 to be off. A signal b and a switch switching signal c for switching the switch 27 so as to output a reception sequence number counter output value are output. The switch 23 switches based on the switch switching signal a. The retransmission data passes through the switch 23 and is input to the switch 25, the retransmission data storage memory 40, the transmission data amount measurement unit 28, the error detection code calculation unit 29, and the multiplexing unit 30 as selected transmission data. The switch 25 switches based on the switch switching signal b. The selected transmission data is switch 2
5, the transmission sequence number counter 26 does not operate. The switch 27 switches based on the switch switching signal c, and outputs the output value of the reception sequence number counter as the transmission sequence number. The retransmission data storage memory 40 does not perform a rewriting operation. The transmission data amount measurement unit 28
It measures the amount of input transmission data and outputs the amount of transmission data. The packet size determining unit 31 determines the packet size based on the amount of transmission data and the presence or absence of the received retransmission request, and outputs the packet size. The error correction code operation unit 45 calculates an error correction code (FEC code) of the transmission sequence number and outputs an error correction code (FEC code). The error detection code operation unit 29 performs an error detection code (CRC) process on the selected transmission data, the error detection code (CRC code) and the error correction code (FEC code) of the transmission sequence number.
C code) and outputs the result. The multiplexing unit 30 multiplexes the selected transmission data, transmission sequence number, error detection code (CRC code) and error correction code (FEC code) based on the input packet size, and outputs the multiplexed data as transmission multiplexed data. I do. The transmission multiplexed data is converted to baseband data by the baseband processing unit 32 and converted to radio waves by the RF module 33.

In this way, the response data to the retransmission request is transmitted from the primary station to the secondary station. The response data is received by the secondary station, and the same receiving operation as in the state where no error occurs on the communication network is performed, and the state transits to the normal communication state.

The configuration of a communication packet in the ARQ communication method according to the present embodiment will be described with reference to FIG. The communication packet is configured to be sandwiched between an opening flag (Op flag) and an ending flag (Ed flag). In the meantime, sequence number N (S), FEC (Forword Error Correction) error correction code for sequence number N (S), data, CRC (Cyclic Redundancy Checki)
ng) Error detection code is included. The opening flag is used to identify the start of the packet, and the ending flag is used to identify the end of the packet. The sequence number N (S) is used for transmitting to the receiving side what number packet the transmitting side is transmitting at the time of transmission, and at the time of receiving, for confirming that double capture and packet dropout do not occur at the receiving side. Used. FEC for sequence number N (S)
Is used for error detection and error correction of the sequence number N (S). The data stores communication data to be transmitted or a command such as a retransmission request. The CRC error detection code uses the sequence number N (S), the FEC for the sequence number N (S), and the remainder obtained by dividing the data by the generator polynomial.

Next, the timing for detecting a sequence number error (sequential number discontinuity error) when a transmission line error occurs will be described with reference to FIG. When a transmission path error occurs as shown in FIG. 1, either an operation of detecting a packet during the occurrence of the transmission path error or discarding the packet due to a CRC error is performed.
Therefore, one or more packets are lost. afterwards,
Even if a transmission path error has occurred, if the opening flag can be detected, a sequence number error (non-consecutive error) can be detected after correcting the sequence number FEC error. Therefore sequence number error (non-sequential error)
Is detected as shown in FIG.

Finally, the ARQ communication method according to the present embodiment as described above will be described with reference to the flowchart of the ARQ communication method of FIG. FIG. 5 mainly shows the flow on the secondary station side. First, the receiving side starts detection of an opening flag (S1). After detecting the opening flag, the FEC of the sequence number is checked (S2). FEC
If an error is detected, the sequence number error is corrected using the FEC code, and if there is no FEC error, nothing is performed (S3, receiving sequence number output step). After the FEC inspection of the sequence number, the continuity of the sequence number is checked (S4, continuity check step). If the sequence number received this time is a value that is continuous with the sequence number that was received immediately before, it is determined that the data was received in the correct order, and fetching of the received data is started. If the sequence number received this time is a discontinuous value with the sequence number received normally immediately before, it is determined that double capture or packet dropout has occurred, and a retransmission request is issued to the primary station side (S5, The retransmission request issuance step) and the reception data are not fetched (S6).
When the continuity of the sequence numbers is confirmed, the detection of the ending flag is started (S7). The data received during this time is temporarily stored in a memory or the like. The packet size is determined by detecting the ending flag. The CRC error of the packet is checked using the CRC error detection code added at the end of the packet (S8). CR
If a C error is detected, it is determined that there is an error in the received data, the received data is discarded (S6), and the opening of the opening flag is awaited to receive the next packet.
If no CRC error is detected, the received data is determined to be error-free and stored, and an opening flag detection wait is waited for receiving the next packet (S9).

As shown in FIG. 4, A according to the present embodiment
The timing of sequence number error detection when a random error frequently occurs in the RQ communication method will be described. If the error period is short but frequent and errors occur,
In particular, even when the error-free period from the end of the error occurrence period to the next error occurrence period is shorter than the packet size, the sequence number N (S) field and the sequence number N
By correcting the sequence number N (S) using the FEC field for (S) and examining the continuity of the sequence numbers, it is possible to detect a sequence number error (non-continuous error) at a timing earlier than before. Has become.

As described above, according to the present embodiment, the error correction of the sequence number field portion is enabled by adding the FEC error correction code for the sequence number N (S).
It is possible to perform a retransmission request earlier by checking the reception sequence number prior to the error check.

[0045]

As described above, according to the ARQ communication method according to the first aspect of the present invention, a communication packet includes an opening flag, a transmission sequence number, a transmission sequence number FEC error correction code, data, and a CRC error detection. A that performs communication using a communication packet composed of a code and an ending flag
A receiving sequence number output step of, when an error in the receiving sequence number is detected, performing a correction using a transmission sequence number FEC error correction code and outputting the corrected reception sequence number; By having a continuity check step for checking the continuity of sequence numbers and a retransmission request issue step for issuing a retransmission request as a retransmission request to be transmitted when a discontinuity error is detected in the continuity check step, the FEC error correction code , The error of the reception sequence number can be corrected, and the reception sequence number can be checked before the CRC error check.
When a discontinuous error is detected, a retransmission request is issued as a retransmission request to be transmitted, and an advantageous effect that a retransmission delay can be reduced can be obtained.

According to the ARQ communication apparatus of the second aspect, an opening flag, a transmission sequence number, a transmission sequence number FEC error correction code, data, a CRC error detection code,
An ARQ communication device that performs communication using a communication packet including an ending flag, comprising: an error correction code operation unit configured to generate an FEC error correction code for a transmission sequence number;
Transmission sequence number and FEC error correction code for transmission sequence number,
A multiplexing unit that multiplexes data and a CRC error detection code;
Transmission sequence number and FEC error correction code for transmission sequence number,
A demultiplexing unit that separates data and a CRC error detection code, a reception sequence number counter that counts when a retransmission request to be transmitted is a non-retransmission request, and a transmission sequence number FEC error when an error in the reception sequence number is detected An error correction unit that performs correction using a correction code and outputs the corrected reception sequence number, and outputs the reception sequence number as a corrected reception sequence number if no error of the reception sequence number is detected. If the corrected reception sequence number output from the error correction unit and the reception sequence number counter output value output from the reception sequence number counter do not match, a reception sequence number comparison is output as a retransmission request to be transmitted. By having the FEC error correction code, the reception sequence number can be corrected by adding the FEC error correction code. It is possible to inspect the signal sequence number, advantageous effect when it detects a non-continuous errors can be shortened issued to retransmit delay a retransmission request as a retransmission request transmitted can be obtained.

[Brief description of the drawings]

FIG. 1 is a timing chart showing a packet configuration and a sequence number error detection timing for a transmission line error occurrence in an ARQ communication method according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an ARQ communication device to which the ARQ communication method according to the first embodiment of the present invention is applied.

FIG. 3 is a block diagram showing an ARQ communication device to which the ARQ communication method according to the first embodiment of the present invention is applied;

FIG. 4 is a timing chart showing a sequence number error detection timing for a random error occurrence in the ARQ communication method according to the first embodiment of the present invention.

FIG. 5 is a flowchart illustrating an ARQ communication method according to the first embodiment of the present invention.

FIG. 6 is a format diagram showing a format of a sequence number field.

FIG. 7 is a timing chart showing a packet configuration and a sequence number error detection timing for occurrence of a transmission line error in a conventional ARQ communication method.

FIG. 8 shows a conventional AR to which a conventional ARQ communication method is applied.
Block diagram showing a Q communication device

FIG. 9 shows a conventional AR to which a conventional ARQ communication method is applied.
Block diagram showing a Q communication device

FIG. 10 is a timing chart showing a sequence number error detection timing for a random error occurrence in a conventional ARQ communication method.

FIG. 11 is a flowchart for explaining a conventional ARQ communication method.

[Explanation of symbols]

 23, 25, 27, 36, 42, 43 Switch 24 Switch switching determining unit 26 Transmission sequence number counter 28 Transmission data amount measuring unit 29 Error detection code calculating unit 30 Multiplexing unit 31 Packet size determining unit 32 Baseband processing unit 33 RF Module 34 Separation unit 35 Error detection code operation unit 37 Error detection code comparator 38 Reception sequence number counter 39 Retransmission sequence number storage memory 40 Retransmission data storage memory 41 Reception sequence number comparator 44 Data type identification unit 45 Error correction code Operation unit 46 Error correction unit

Claims (2)

[Claims] An ARQ communication method for performing communication using a communication packet including an opening flag, a transmission sequence number, an FEC error correction code for transmission sequence number, data, a CRC error detection code, and an ending flag. FEC for transmission sequence number when sequence number error is detected
A receiving sequence number output step of performing correction using an error correction code and outputting as a corrected receiving sequence number, a continuity checking step of checking continuity of the receiving sequence number, and a non-continuous error in the continuity checking step. And a retransmission request issuing step of issuing a retransmission request as a retransmission request to be transmitted when is detected. 2. An ARQ communication apparatus for performing communication using a communication packet including an opening flag, a transmission sequence number, an FEC error correction code for transmission sequence number, data, a CRC error detection code, and an ending flag. An error correction code operation unit for generating a sequence number FEC error correction code, a multiplexing unit for multiplexing a transmission sequence number and a transmission sequence number FEC error correction code, data, and a CRC error detection code; a transmission sequence number and transmission A demultiplexing unit that separates the sequence number FEC error correction code, data, and CRC error detection code, a reception sequence number counter that counts when a retransmission request to be transmitted is a non-retransmission request, and a case where an error in the reception sequence number is detected Is corrected using the transmission sequence number FEC error correction code, and is output as a corrected reception sequence number. If no error is detected, an error correction unit that outputs the reception sequence number as it is as a corrected reception sequence number, and the corrected reception sequence number and the reception sequence number counter output from the error correction unit. An ARQ communication device comprising: a reception sequence number comparator that outputs a retransmission request as a retransmission request to be transmitted when the output value of the output reception sequence number counter does not match.