JPH09116442A - Decoding device and method for correcting error of product code - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize decoding at high speed with a small-scaled circuit by storing only a received word which is error-detected without error-correcting an error correction result in a first direction and previously calculating a syndrome for an error correction operation in a second direction. SOLUTION: In a first error correction decoding device, an error position and an error numeric value are calculated, and the error correction result is written into a second storage means 7. The received word which cannot be error-detected and therefore error-detected is written into a first storage means 3 with a first direction number. At the same time, the syndromes are calculated, and they are sequentially stored in plural syndrome registers 4. A selector 5 sequentially selects a pair of syndromes corresponding to the received word in the second direction and a second error correction decoding device 6 calculates the error position and the error numeric value. The error correction operation for a content stored in the first storage means 3 is executed and the corrected result is written into the second storage means 7. Thus, an operation for reading all the received words by the error correction operation of the second direction can be omitted and decoding can be executed at high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an error correction decoding device and an error correction decoding method in a digital recording device or digital broadcasting.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional product code error correction decoding apparatus disclosed in, for example, Japanese Patent Laid-Open No. 2-239729, in which 101 is a data bus and 102 is a memory for storing one block of product code. , 103 is a C1 decoding device that performs an error correction decoding operation in a first direction on the content read from the memory 102, and 104 is an error correction decoding operation in a second direction on the content read from the memory 102. A C2 decoding device to perform, 105 is an erasure flag storage device that stores the position of the received word that was not error-corrected in the error correction operation in the first direction as erasure, and 106 is a control device that controls the error correction operation of the product code. .

Next, the operation will be described. First, the received words of the product code from the data bus 101 are sequentially C1 decoding device 103.
Is input to Then, the C1 decoding device 103 performs error correction, and the error-corrected data is transferred to the data bus 101.
Is written in the memory 102 via. The above operation is performed for all the received words in the first direction that form the product code. In addition, the position of the received word in which the error cannot be corrected and the error is detected is stored in the erasure position storage device 105 as the erasure.

Next, C1 stored in the memory 102
The decoded data is sequentially read in the second direction and input to the C2 decoding device 104. And the C2 decoding device 104
The error-corrected data is output using the contents stored in the erasure position storage means 105, and is output via the data bus 101. In addition, the output data is written in a memory different from the memory 102 in order to use the output data for other systems. The above operation is controlled by the control device 106.

[0005]

Since the conventional product code error correction decoding apparatus is configured as described above, the memory for one block of the product code is used to perform the error correction operation in the second direction. There is a problem that the circuit scale becomes large because the capacity must be at least.

Further, when performing the error correction decoding operation in the second direction, all the received words in which the error correction in the first direction has been performed must be read from the memory, which causes a problem that the decoding time becomes long. was there.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain an error correction decoding apparatus for a product code in which the memory capacity of the storage means is reduced and the circuit scale is reduced. And It is another object of the present invention to provide an error correction decoding apparatus for a product code that can be decoded at high speed by not reading all received word data from the storage unit when performing the error correction operation in the second direction.

Further, in the error correction decoding operation in the second direction, when there is a high possibility that an error correction is performed, it is another object to prevent the error correction operation from being performed so as to reduce the occurrence of error correction as much as possible. .

Another object of the present invention is to reduce residual errors after decoding by performing error correction as much as possible in error correction decoding operations in the second direction.

It is another object of the present invention to obtain an error correction decoding device having a small circuit scale by sharing the error correction decoding device in the first direction and the error correction decoding device in the second direction.

Another object of the present invention is to prevent erroneous correction from occurring in the error correcting operation in the second direction when the first storage means overflows.

Another object of the present invention is to reduce the residual error after decoding by the error correction operation in the second direction when the first storage means overflows.

Further, according to the present invention, by writing not only the received word which has not been error-corrected in the error correction operation in the first direction and whose error has been detected, but also the received word which is highly likely to be erroneously corrected, into the first storage means, It is an object of the present invention to reduce erroneous correction and writing in the second storage means in the error correction operation in the first direction and reduce residual errors after decoding.

Further, the present invention enhances the error detection capability by performing the CRC check in the error correction operation in the first direction, reduces the error correction in the error correction operation in the first direction, and reduces the residual error after decoding. The purpose is to do.

[0015]

According to a first aspect of the present invention, there is provided a product code error correction decoding apparatus, comprising: a first error correction decoding apparatus for performing error correction on a received word in a first direction;
First storage means for storing only the received words that have been error-corrected in the first error-correction decoding device, and a plurality of sets of syndrome registers for calculating and storing the syndromes of the received words in the second direction. A second error correction decoding device for performing error correction on the received word in the second direction from the contents of the plurality of sets of syndrome registers;
Second storage means for storing the result of error correction performed by the second error correction decoding device for the received word that has been error corrected by the error correction decoding device and the contents stored in the first storage device. It is equipped with and.

According to a second aspect of the present invention, in the error correction decoding apparatus for a product code, in the second error correction operation of the second error correction decoding apparatus, the data corresponding to the calculated error position is the first data. When the data is stored in the first storage means, the error correction is performed, and when the data corresponding to the calculated error position is not stored in the first storage means, the error correction is not performed. .

An error correction decoding apparatus for a product code according to a third aspect of the present invention is an error calculated for each received word in an error correction operation of the second error correction decoding apparatus in the second direction. Error correction is performed only when all the data corresponding to the position is stored in the first storage means, and an error is generated if even one data corresponding to the calculated error position is not stored in the first storage means. The configuration is such that no correction is made.

An error correction decoding device for a product code according to a fourth aspect of the present invention performs an error correction for a received word in the first direction and an error correction for a received word in the second direction. The decoding device is commonly used and is constructed by one error correction decoding device.

According to a fifth aspect of the present invention, in the error correction decoding apparatus for a product code, a received word whose error cannot be corrected and is detected as an error by an error correction operation in the first direction by the first error correction decoding apparatus. When the first storage means overflows, the second storage means stores the received word in which the error has been detected because the overflow cannot be corrected and the second error correction decoding device operates in the second direction. The contents of the first storage means are directly written to the second storage means without performing the error correction operation.

According to the sixth aspect of the present invention, in the error correction decoding apparatus for the product code, the received word whose error cannot be corrected by the first error correction decoding apparatus and which is error-corrected by the error correction operation in the first direction is detected. In many cases, when the first storage means overflows, the second storage means stores the received word that has been error-detected without overflow error correction,
The error correction decoding device performs error correction operation when the data corresponding to the calculated error position is stored in the first storage means, and the data corresponding to the calculated error position is stored in the first storage means. If it is not stored in, the error correction operation is not performed.

According to a seventh aspect of the present invention, in the error correction decoding apparatus for a product code, when an error cannot be corrected and an error is detected by the error correction operation in the first direction by the first error correction decoding apparatus, reception is performed. The word data is directly written in the first storage means, and when the error correction is possible and the number of errors is larger than a predetermined number, the error-corrected data is stored in the first storage means. It is a thing.

An error correction decoding apparatus for a product code according to claim 8 of the present invention performs a CRC check on each error-corrected information bit in the first direction, and when an error is detected, it is received. First word or error-corrected received word
It is designed to be written in the storage means.

An error correction decoding method for a product code according to a ninth aspect of the present invention is a first error correction decoding step for performing error correction on a received word in a first direction, and the first error correction decoding step. In the first storage step, only a received word whose error has not been corrected and whose error is detected is stored in the first storage means; and a step of calculating the syndrome of the received word in the second direction and storing it in a plurality of sets of syndrome registers. And a second error correction decoding step for performing error correction on the received word in the second direction from the contents of the plurality of sets of syndrome registers, and a received word that has been error corrected in the first error correction decoding step. The result stored in the first storage means in the first storage means is error-corrected by the second error-correction decoding step, and the result is second-stored. Those having a second storage step of storing.

In the error correction decoding method for a product code according to claim 10 of the present invention, in the second error correction decoding step, the data corresponding to the calculated error position is stored in the first storage means. If the data corresponding to the calculated error position is not stored in the first storage means, the error correction is not performed.

According to the eleventh aspect of the present invention, in the error correction decoding method for a product code, in the second error correction decoding step, all the data corresponding to the error position calculated for each received word is the first. The error correction is performed only when the data is stored in the first storage means, and the error correction is not performed when even one data corresponding to the calculated error position is not stored in the first storage means.

In the error correction decoding method for a product code according to the twelfth aspect of the present invention, in the error correction operation in the first direction by the first error correction decoding step, the received word whose error cannot be corrected and whose error is detected is When the number of overflows in the first storage means becomes large and the overflowed error cannot be corrected, the received word detected by the error detection is written in the second storage means, and the second error correction decoding step is performed in the second direction. The contents of the first storage means are directly written to the second storage means without performing the error correction operation.

According to a thirteenth aspect of the present invention, in the error correction decoding method for a product code, a received word in which an error cannot be corrected and an error is detected by an error correction operation in the first direction by the first error correction decoding step. When the overflow occurs in the first storage means, the overflowed error cannot be corrected and the error-detected received word is written in the second storage means, and the second error correction decoding step is performed at the calculated error position. If the corresponding data is stored in the first storage means, the error correction operation is performed, and if the data corresponding to the calculated error position is not stored in the first storage means, the error correction operation is performed. I decided not to do it.

According to the fourteenth aspect of the present invention, in the error correction decoding method for a product code, when an error is detected in the first error correction decoding step without being able to correct the error, the data of the received word is directly converted into the first word. An error correction decoding method for a product code, wherein data that has been error-corrected when it is written in the storage means and error correction is possible and the number of errors is larger than a predetermined number is stored in the first storage means.

According to a fifteenth aspect of the present invention, in the error correction decoding method of the product code, when the CRC bit is added to each information bit in the first direction, the error correction operation in the first direction is performed. A CRC check is performed on the received word, and when it is detected that an error remains, the received word data or the error-corrected received word data is written to the first storage means.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, 1 is an input terminal for inputting received word data of a product code, 2 is a first error correction decoding device for performing an error correction operation of a product code in a first direction, and 3 is a first
The storage capacity of the product code 1 is stored in the first storage means for storing the received word whose error has not been corrected by the error correction decoding device 2 and whose error has been detected, and the number of the received word whose error has been detected.
The capacity is limited to a block or less. 4 is a plurality of sets of syndrome registers for calculating and storing syndromes in advance when performing error correction operation of the product code in the second direction, and 5 is 1 from the outputs of the plurality of sets of syndrome registers 4.
A selector that selects the contents of a set of syndrome registers,
Reference numeral 6 is a second error correction decoding device that performs an error correction operation in the second direction from the contents of one set of syndrome registers output from the selector 5, and 7 is a received word error-corrected by the first error correction decoding device 2. And second storage means for storing the data decoded by the second error correction decoding device 6 with respect to the contents stored in the first storage means 3, and 8 is the data after error correction of the product code Is an output terminal for outputting.

Next, the operation will be described. First, the received word is input from the input terminal 1 to the first error correction decoding device 2 for each received word in the first direction. The error position and the error value are calculated in the first error correction decoding device 2, and if the error correction is possible, the result of the error correction is written in the second storage means 7. Further, for the received word that is error-correctable and error-detected, the number of the received word in the first direction that is input as the received word in the first storage means 3 is given to the first storage means 3.
Write to.

In addition, when the received word in the first direction is written in the first storage means 3 or the second storage means 7, error correction in the second direction is performed in each syndrome register of the plurality of sets of syndrome registers 4. The syndrome is calculated and stored in each syndrome register.

Next, the selector 5 sequentially selects one set of syndromes corresponding to the received word in the second direction from the plurality of sets of syndrome registers 4, and the second error correction decoding device 6 determines the error position. An error numerical value is calculated, an error correction operation is performed on the contents stored in the first storage means 3, the error storage operation is written in the second storage means 7, and a second word is output to the output terminal 8 of the error-corrected received word. The contents of the storage means 7 are sequentially output.

By the above operation, the capacity of the first storage means 3 can be reduced and the circuit can be reduced in order to store only the received word which could not be error-corrected by the error correction operation in the first direction in the first storage means 3. The scale can be reduced. In addition, since the syndrome is calculated in advance when performing the error correction operation in the second direction, the error correction operation can be performed without reading the received word from the storage unit, so that the error correction decoding operation can be performed at high speed.

FIG. 2 is a block diagram showing details of the second error correction decoding device 6 in the first embodiment. In the figure, 9 is a syndrome register for storing a set of syndromes selected by a selector 5 from a plurality of syndrome registers 4, 10 is an error position calculation unit for calculating an error position of a received word from the contents of the syndrome register 9, 11 Is an error position register that stores the error position calculated by the error position calculation unit 10, 12 is an error value calculation unit that calculates an error value corresponding to the error position from the contents of the syndrome register 9, and 13 is an error value calculation unit 12. An error number register for storing the calculated error number, 14 is a storage position register for storing the number of the received word stored in the first storage means 3, that is, the position of the received word in the second direction, 15 Is a received word register for storing the received words stored in the first storage means 3 among the received words in the second direction, 6 adders for performing error correction, 17
Is the contents of the error position register 11 and the storage position register 14
Reference numeral 18 is a comparator for comparing the contents of the above, and reference numeral 18 is a selector for selecting whether to output the received word as it is or output the error-corrected data.

Next, the operation will be described. First, for the error correction operation in the first direction, the error correction is performed by the method described above, and the error-corrected received word is written in the second storage means 7, and the error cannot be corrected and the error is detected. The received word and the number of the received word are written in the first storage means 3. Also, the received word data in the first direction is stored in the first storage means 3.
, The syndromes of the received word in the second direction are calculated in the plurality of syndrome registers 4 and stored in the syndrome registers.

Next, the first error detected by the first error correction decoding device 2 stored in the first storage means 3 is detected.
Write all the contents of the number of the received word in the direction of to the storage location register 14. Then, one set of syndromes corresponding to the received word in the second direction is sequentially selected by the selector 5 and written in the syndrome register 9. The syndrome written in the syndrome register 9 is stored in the error position calculation unit 10
The error position and the error value are calculated by the error value calculator 12 and stored in the error position register 11 and the error value register 13, respectively.

Next, the comparator 17 checks whether or not all the contents stored in the error position register 11 are stored in the storage position register 14. Also,
Of the received words in the second direction, the contents stored in the first storage means 3 are read out and stored in the received word register 15.

As a result of the comparison by the comparator 17, if all the contents stored in the error position register 11 are stored in the storage position register 14, the error stored in the error position register 11 is detected. With respect to the data of the received word register 15 corresponding to the position, the contents of the error number register 13 are added by the adder 16, selected by the selector 18 and output, and written in the second storage means 7. Regarding the data stored in the error position register 11 and not corresponding to the error position, the content of the received word register 15 is selected by the selector 18 and output, and written in the second storage means 7.

Further, as a result of comparison by the comparator 17, when all the contents stored in the error position register 11 are not in the storage position register 14, all the contents of the received word register 15 are selected by the selector 18 and output. Then second
To the storage means 7.

By the above operation, in the error correction operation in the second direction, if the data corresponding to the calculated error position is not stored in the first storage means 3, error correction can be performed by performing error correction. Therefore, the occurrence of erroneous correction can be suppressed by not performing the error correction in the above case.

Embodiment 2. As another embodiment, in the comparator 17 shown in FIG.
It is checked whether the contents stored in memory location register 14 are stored. As a result of the comparison by the comparator 17, if the contents stored in the error position register 11 are in the storage position register 14, the received word register 15 corresponding to the error position stored in the error position register 11 is stored. Error number register 1 for data
3 is added in the adder 16 and the selector 18
It is selected and outputted by and written in the second storage means 7. Regarding the data stored in the error position register 11 and not corresponding to the error position, the content of the received word register 15 is selected by the selector 18 and output, and written in the second storage means 7.

By the above operation, in the error correction operation in the second direction, if the data corresponding to the calculated error position is stored in the first storage means 3, the error correction operation is performed in any case. Therefore, residual errors after decoding are reduced.

Embodiment 3. 3 is an error correction decoding apparatus for a product code showing another embodiment, and 19 is an error correction decoding apparatus in which the first error correction decoding apparatus 2 and the second error correction decoding apparatus 6 in FIG. 1 are shared. Is.

Next, the operation will be described. First, the received word is input from the input terminal 1 to the error correction decoding device 19 for each received word in the first direction. The error position and the error numerical value are calculated in the error correction decoding device 19, and if the error correction is possible, the result of the error correction is written in the second storage means 7. Further, for the received word whose error cannot be corrected and whose error is detected, the received word and the input number of the received word in the first direction are written in the first storage means 3.

In addition, when the received word in the first direction is written in the first storage means 3 or the second storage means 7, error correction in the second direction is performed in each syndrome register of the plurality of sets of syndrome registers 4. The syndrome is calculated and stored in the syndrome register.

Next, the selector 5 sequentially selects one set of syndromes corresponding to the received word in the second direction from the plurality of sets of syndrome registers 4, and the error correction decoding device 19 determines the error position and the error value. Calculate and first storage means 3
An error correction operation is performed on the contents stored in the second storage unit 7, the contents are written in the second storage unit 7, and the contents of the second storage unit 7 are sequentially output to the output terminal 8 of the error-corrected received word.

With the above operation, the error correction decoding apparatus can be configured with a common circuit for both the error correction operation in the first direction and the error correction operation in the second direction. Can be made smaller.

Embodiment 4 FIG. 4 shows a product code error correction decoding device according to another embodiment, and 20 is an overflow detection device for detecting an overflow of the first storage means 2.

Next, the operation will be described. First, the received word is input from the input terminal 1 to the first error correction decoding device 2 for each received word in the first direction. The error position and the error value are calculated in the first error correction decoding device 2. When the overflow detection device 20 has not detected an overflow in the first storage means 3, if the error can be corrected, the result of the error correction is written in the second storage means 7 to correct the error. If the received word is erroneously detected and an error is detected, the received word and the input number of the received word in the first direction are written in the first storage means 3.

On the other hand, when the overflow detection device 20 detects the overflow of the first storage means 3, if the error correction of the received word in the first direction is possible, the result of the error correction is used as the second result. In the second storage means 7, the received word is written into the second storage means 7 even if the received word is error-corrected and error-corrected.

Further, when the received word in the first direction is written in the first storage means 3 or the second storage means 7, error correction in the second direction is performed in each syndrome register of the plurality of sets of syndrome registers 4. The syndrome is calculated and stored in the syndrome register.

Then, the contents stored in the first storage means 3 are directly written into the second storage means 7 without performing the error correction operation in the second direction by the second error correction decoding device 6. To

With the above operation, in the error correction operation in the second direction, when the first storage means overflows, there are generally many errors remaining when the decoding in the first direction is completed. When the error correction operation in the second direction is performed, the possibility of erroneous correction increases. Therefore, the error correction can be suppressed by not performing the error correction operation in the second direction.

Embodiment 5. As another embodiment, in the same configuration as that of the fourth embodiment, when an overflow occurs in the first storage means 3, the same error correction operation in the first direction by the first error correction decoding device 2 is performed. However, in the error correction operation in the second direction by the second error correction decoding device 6, the data corresponding to the error position calculated by the second error correction decoding device 6 is the first storage means. If it is stored in No. 3, the calculated error value is added to the content of the first storage unit 3 and written in the second storage unit 7.

By the above operation, in the error correction operation in the second direction, when the data corresponding to the calculated error position is stored in the first storage means 3, the error correction operation is performed in any case. Therefore, residual errors after decoding are reduced.

Embodiment 6 FIG. FIG. 5 shows an error correction decoding device for a product code according to another embodiment, and 21 is an error number calculation device for calculating the number of errors in the error correction operation in the first direction.

Next, the operation will be described. First, the received word is input from the input terminal 1 to the first error correction decoding device 2 for each received word in the first direction. The error position and the error value are calculated in the first error correction decoding device 2. In addition, the error number calculation device 21 calculates the error number of the received word in the first direction. If the number of errors calculated by the error number calculation device 21 is less than or equal to a predetermined number of errors, the result of error correction is stored in the second storage means 7 for those that can be corrected. Try to write.

On the other hand, when the number of errors calculated by the error number calculation device 21 is larger than the predetermined number of errors, for those that can be corrected, the result of error correction and the input first The number of the received word in one direction is written in the first storage means 3. Further, even for a received word in which error correction is not possible and an error is detected, the received word and the number of the input received word in the first direction are written in the first storage means 3.

Further, when the received word in the first direction is written in the first storage means 3 or the second storage means 7, error correction in the second direction is performed in each syndrome register of the plurality of sets of syndrome registers 4. The syndrome is calculated and stored in the syndrome register.

For the error correction operation in the second direction, refer to the second
If the data corresponding to the error position calculated by the error correction decoding device 6 is stored in the first storage means 3, the calculated error numerical value is added to the content of the first storage means, 2 is written in the storage means 7.

By the above operation, the possibility that the received word which has been erroneously corrected in the error correction operation in the first direction by the first error correction decoding device 2 is less likely to be written in the second storage means 7 is reduced. In the error correction operation in the second direction by the error correction decoding device 6, residual errors after decoding are reduced.

Embodiment 7 FIG. FIG. 6 shows a product code error correction decoding device according to another embodiment, and 22 is a CRC check device for performing a CRC check on the information bits that have undergone the error correction operation in the first direction.

Next, the operation will be described. First, the received word is input from the input terminal 1 to the first error correction decoding device 2 for each received word in the first direction. The error position and the error value are calculated in the first error correction decoding device 2, and the error correction operation is performed. In addition, the CRC check device 22 performs a CRC check on the information bits that have been error-corrected.
Then, if no error is detected by the CRC check device 22, the result of error correction is written in the second storage means 7.

On the other hand, when an error is detected in the CRC checking device 22, the result of the error correction or the received word and the number of the input received word in the first direction are stored in the first storage means 3. Write.

In addition, when the received word in the first direction is written in the first storage means 3 or the second storage means 7, error correction in the second direction is performed in each syndrome register of the plurality of sets of syndrome registers 4. The syndrome is calculated and stored in the syndrome register.

For the error correction operation in the second direction, refer to the second
If the data corresponding to the error position calculated by the error correction decoding device 6 is stored in the first storage means 3, the calculated error numerical value is added to the content of the first storage means 3, It is written in the second storage means 7.

With the above operation, error detection can be performed more accurately in the error correction operation in the first direction.
The possibility of erroneous correction is reduced, the erroneous correction is reduced in the error correction operation in the second direction, and the residual error after decoding is reduced.

[0069]

As described above, according to the present invention, the storage means for storing the error correction result in the first direction cannot store the error correction, and only the received word in which the error is detected is stored, so that the storage capacity is limited. Therefore, the circuit scale can be reduced, and since the syndrome is calculated in advance in the error correction operation in the second direction, the operation of reading all received words from the storage unit can be omitted, and the decoding can be performed at high speed. There is.

Further, according to the present invention, in the error correction operation in the second direction, even one piece of data corresponding to the error position calculated for each received word is not stored in the first storage means. In that case, there is a high possibility that error correction will occur, and in that case, we did not perform error correction operation.
There is an effect that something that is unlikely to be erroneously corrected can be obtained

According to the present invention, in the error correction operation in the second direction, when the data corresponding to the calculated error position is stored in the first storage means, the error correction operation is performed. There is an effect that residual errors after decoding are reduced.

According to the present invention, the error correction decoding device for performing the error correction operation in the first direction and the error correction decoding device for performing the error correction operation in the second direction are made common, There is an effect that a product code error correction decoding device with a small circuit scale can be obtained.

Further, according to the present invention, when an error correction operation in the second direction is performed when the first storage means overflows, there is a high risk of erroneous correction.
By not performing error correction operation in the direction,
It has the effect of suppressing erroneous correction.

Further, according to the present invention, when the first storage means overflows, the data corresponding to the error position calculated when performing the error correction operation in the second direction is the first storage means. If the data is stored in, the error correction operation is performed on the data, which has the effect of reducing the residual error after decoding.

Further, according to the present invention, in the error correction operation in the first direction, not only the received word in which the error cannot be corrected but the error is detected, but the error correction is performed even when the number of errors is larger than the predetermined number. By storing the result in the first storage means, it is possible to reduce the possibility that the error will be erroneously corrected and written in the second storage means in the error correction operation in the first direction and the residual error after decoding will be reduced. .

Further, according to the present invention, in the error correction operation in the first direction, the CRC is applied to the error-corrected result.
As a result of the check, if an error is detected, the received word is stored in the first storage means, which has the effect of reducing the residual error after decoding.

[Brief description of the drawings]

FIG. 1 is a block diagram of a product code error correction decoding device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a second error correction decoding device of a product code error correction decoding device according to another embodiment of the present invention.

FIG. 3 is a block diagram showing a product code error correction decoding device according to another embodiment of the present invention.

FIG. 4 is a block diagram showing a product code error correction decoding apparatus according to another embodiment of the present invention.

FIG. 5 is a block diagram showing an error correction decoding device for a product code according to another embodiment of the present invention.

FIG. 6 is a block diagram showing an error correction decoding device for a product code according to another embodiment of the present invention.

FIG. 7 is a block diagram showing a conventional product code error correction decoding device.

[Explanation of symbols]

2: First error correction decoding device 3: First storage means 4: Syndrome register 6: Second error correction decoding device 7: Second storage means 17: Comparator 19: Error correction decoding device 20: Overflow Detection device 21: Error number calculation device 22: CRC
Checking device

Claims (15)

[Claims] 1. A first error correction decoding apparatus that performs error correction on a received word in a first direction, and stores only a received word that is error-corrected and cannot be corrected by the first error-correction decoding apparatus. Error correction from the contents of the plurality of sets of syndrome registers for the received word in the second direction. A second error correction decoding apparatus for performing the above, and the second error correction decoding apparatus for the received word that has been error corrected by the first error correction decoding apparatus and the contents stored in the first storage means. An error correction decoding apparatus for a product code, comprising: a second storage unit that stores a result of error correction by the above. 2. The second error correction decoding device performs error correction in the error correction operation in the second direction when data corresponding to the calculated error position is stored in the first storage means. The error correction decoding apparatus for a product code according to claim 1, wherein error correction is not performed when data corresponding to the calculated error position is not stored in the first storage means. 3. The second error correction decoding apparatus, in the error correction operation in the second direction, all the data corresponding to the error position calculated for each received word is stored in the first storage means. The error correction is performed only when the error correction is performed, and the error correction is not performed when even one data corresponding to the calculated error position is not stored in the first storage means. Error correction decoding device for product code. 4. The error correction decoding device for a product code according to claim 1, wherein the first error correction decoding device and the second error correction decoding device are configured by a single error correction decoding device. . 5. An error correction operation in the first direction by the first error correction decoding apparatus is performed, and it is detected that the number of received words in which errors cannot be corrected and error detection is performed increases, and the first storage means overflows. An overflow detection device is provided, and when the overflow detection device detects an overflow, the second storage means stores the received word that has been error-detected without overflow error correction, and the second error-correction decoding device has the second direction. Error correction operation of
2. The error correction decoding apparatus for a product code according to claim 1, wherein the content of the storage means is written into the second storage means as it is. 6. An overflow for detecting that the first storage means has overflowed due to a large number of received words in which errors cannot be corrected by the error correction operation in the first direction by the first error correction decoding device. Equipped with a detection device, when the overflow detection device detects an overflow,
The second storage means stores the received word that has been error-detected without overflow error correction, and the second error-correction decoding device stores the data corresponding to the calculated error position in the first storage means. The error correction operation is performed when the error correction operation is performed, and the error correction operation is not performed when the data corresponding to the calculated error position is not stored in the first storage means. An error correction decoding device for the described product code. 7. An error number calculation device for counting the number of errors that can be corrected by an error correction operation in a first direction by the first error correction decoding device, wherein the first error correction decoding device is in the first direction. When the error is not corrected by the error correction operation described above and the error is detected, the data of the received word is directly written in the first storage means, and when the count value of the error number calculation device is larger than a predetermined number, the error correction is performed. 2. The error correction decoding apparatus for a product code according to claim 1, wherein the executed data is stored in the first storage means. 8. A CRC check device for performing a CRC check on a received word subjected to an error correction operation in the first direction by the first error correction decoding device, and a CRC for each information bit in the first direction. When the bit is added, C is applied to the received word that has undergone the error correction operation in the first direction.
The RC check device performs a CRC check, and the first error correction decoding device receives the received word data or the error-corrected received word data in the first storage means when it is detected that an error remains. The error correction decoding apparatus for a product code according to claim 1, wherein the error correction decoding apparatus is configured to write. 9. A first error correction decoding step of performing error correction on a received word in a first direction, and only a received word which is error-corrected in the first error-correction decoding step is detected. A first storing step of storing in one storage means; a step of calculating syndromes of a received word in the second direction and storing the syndromes in a plurality of sets of syndrome registers; Are stored in the first storage means by a second error correction decoding step for performing error correction based on the contents of the syndrome register of 1), a received word that has been error corrected in the first error correction decoding step, and the first storage step. A second storage step of storing in the second storage means the result of error correction by the second error correction decoding step with respect to the contents described above. Code error correction decoding method. 10. The second error correction decoding step comprises:
When data corresponding to the calculated error position is stored in the first storage means, error correction is performed, and when data corresponding to the calculated error position is not stored in the first storage means The error correction decoding method for a product code according to claim 9, wherein error correction is not performed. 11. The second error correction decoding step comprises:
Error correction is performed only when all the data corresponding to the calculated error position for each received word is stored in the first storage means, and even if only one data corresponding to the calculated error position is the first data. 11. The error correction decoding method for a product code according to claim 10, wherein error correction is not performed when the error code is not stored in the storage means. 12. An overflow occurs when an error correction operation in the first direction by the first error correction decoding step causes an error correction and the number of received words to be error-detected increases and the first storage means overflows. The received word which has not been error-corrected and is error-detected is written in the second storage means, and the second error-correction decoding step does not perform the error-correction operation in the second direction. Second as it is
10. The error correction decoding method for a product code according to claim 9, wherein the error correction decoding is performed in the storage means. 13. The first error correction decoding step,
When the first storage unit overflows because of many received words that cannot be corrected by the error correction operation in the first direction and overflows in the first storage unit, the received words that have been error-detected and cannot be corrected are overflowed. Write to the storage means of
The second error correction decoding step performs an error correction operation when the data corresponding to the calculated error position is stored in the first storage means, and the data corresponding to the calculated error position is the first 10. The error correction decoding method for a product code according to claim 9, wherein an error correction operation is not performed if the error code is not stored in the storage means. 14. The first error correction decoding step comprises:
When an error is detected without being able to correct the error, the data of the received word is written as it is to the first storage means, and if the error can be corrected and the number of errors is larger than a predetermined number, the error-corrected data 10. The error correction decoding method for a product code according to claim 9, characterized in that is stored in the first storage means. 15. When a CRC bit is added to each information bit in the first direction, a CRC check is performed on the received word subjected to the error correction operation in the first direction, and an error remains. 10. The error correction decoding method for a product code according to claim 9, wherein the received word data or the error-corrected received word data is written to the first storage means when it is detected that the error has occurred.