KR100327221B1 - Error correction method and circuitry for high density recording media - Google Patents

Abstract

An error correction method and a circuit thereof for a high density recording medium are disclosed in the present invention. The present invention arranges input data in a corrected error correction block based on the size of recordable user data and the size of error correction parity determined according to the minimum mark length and track pitch length, thereby generating error correction encoded data. Including an encoder and an interleaver interleaving the coded data, the parity of the error correction block is increased to increase the error correction capability of the high density recording medium capable of recording approximately 15 Gbytes on the end face.

Description

Error correction method and circuitry for high density recording media

TECHNICAL FIELD The present invention relates to the field of error correction, and more particularly, to an error correction method and a circuit thereof for a high density recording medium.

Increasingly, the amount of data that can be recorded on a single optical disc is increasing, which is necessary to record and play back a large amount of data for a good picture and sound effect, and to function as a computer peripheral. This is to save various information.

To this end, optical discs have evolved from DVDs (digital versatile discs) to capacities of about 600 megabytes (MB). This storage capacity allows for about 135 minutes of moving picture expert group (MPEG) -2 picture quality and audio effects (AC) -3.

However, the recent trend is demanding HDTV quality with the commercialization of High Definition Television (HDTV). In order to meet the demand of HDTV quality, a recording medium with more data storage capacity is required. High-defintion DVD (HD-DVD) discs are being developed for this purpose.

It should be able to store about 15Gbytes, which is about 3.28 times larger than the size that can be stored on a general DVD disc (about 4.7Gbytes), so that users can watch 135 minutes of movies at a level corresponding to HDTV quality. This HD-DVD disc reduces the actual length of the recorded bits, thereby increasing the capacity of the data recorded on a disc of the same size as a DVD-ROM.

However, in this case, when a small scratch occurs on the disc, the size of data loss due to this is inevitably larger than that of a conventional DVD disc. It is an error correction technique that can compensate for such data loss, and according to its application method, it greatly affects the amount of user data recorded and the reliability of user data during recording and playback.

The format for the error correction block used in the DVD-ROM is configured to be 208 bytes in the column direction and 182 bytes in the row direction as shown in FIG. There are 172 bytes of user data and 10 bytes of internal parity in the column direction, 16 sectors of 12 bytes in the row direction, and 16 bytes of external parity in the row direction. Here, one sector is 2KByte (12Byte) × 182 bytes).

When interleaving of such error correction block data is performed, as shown in FIG. 2, the external parity of 16 bytes is arranged so as to be inserted into the last row of every sector having 12 bytes in the row direction.

Here, the size of the entire error correction block is 182 × 208 = 37856 bytes. The range of consecutive errors that can be corrected in this error correction block is 182 bytes. × 16rows. This is because the size of the outer parity is 16 bytes. In fact, there are sync patterns as well as user data and parity when they are written to disk, so this should be taken into account when calculating error correction capability. Two sync patterns are inserted in one row in the column direction.

The magnitude of burst error that can be corrected in an error correction block for a typical DVD-ROM disc is as follows. One line in the column direction is 182 bytes, which should take into account 8 to 16 modulation,

32 bits × 2 + (182 bytes × 8) × 2 times = 2976 bits

The burst size that can be corrected in the entire error correction block is

2976 bits × 16 rows = 47616 bits

to be. Minimum mark length (3T) is 0.4 in DVD-ROM disc format μ m, which is equivalent to 3 bits in terms of channel bits. Therefore, if X is the length that can be corrected,

0.4 μ m: 3 bits = X μ m: 47616 bits

X = 0.000634 m = 6.34 mm

to be. According to the above calculation result, the maximum error size that can be corrected in the error correction block of the DVD-ROM is 47616 bits.

DVD-ROM discs have a minimum recordable size of 0.4 μ m, and the distance between tracks (track pitch) is 0.74 μ m. At this time, since the error correction capability is 16 bytes in the parity direction in the row direction, the error correction capability is configured to allow error correction even if a scratch of about 6.3 mm occurs in the track direction.

Therefore, the error correction capability required by a general optical disc should be able to correct scratches of about 6.3 mm in the track direction of the disc. The DVD-ROM format also requires this level of error correction capability, and based on this, the number of bits that can be corrected in the error correction block is determined.

In the error correction block shown in Fig. 1 used for the DVD disc, the DVD-ROM can correct an error for the same 6.3 mm wound, but not HD-DVD. For DVD-ROM, 47616 bits are affected for a 6.3mm scratch, whereas for HD-DVD, about 156,180 bits, about 3.28 times that, is affected. Therefore, there is a problem that cannot be applied to HD-DVD as an error correction format for a general DVD disc.

In order to solve the above problem, it is an object of the present invention to provide an error correction method for a high density recording medium.

Another object of the present invention is to provide an error correction circuit for a high density recording medium.

In order to achieve the above object, the error correction method according to the present invention is an error correction method for a high density recording medium: determining the size of recordable user data and the size of error correction parity according to the minimum mark length and track pitch length. And generating the error correction coded data for the error correction block having the determined size of the error correction parity.

In order to achieve the above another object, the error correction circuit of the error correction circuit for the high density recording medium according to the present invention is characterized in that the size and error of recordable user data determined according to the minimum mark length and track pitch length. Input data is arranged in the corrected error correction block based on the size of the correction parity, and the error correction coded data is output, and the interleaver interleaves the error correction coded data to output the interleaved data.

1 is a diagram showing the format of an error correction block of a general DVD disk.

FIG. 2 is a diagram illustrating an interleaved result for the error correction block illustrated in FIG. 1.

3 is a block diagram of an error correction circuit for a high density recording medium according to the present invention.

4 is a diagram illustrating a format of an error correction block according to the present invention used in the error correction encoder illustrated in FIG. 3.

FIG. 5 is a diagram illustrating an interleaved result for the error correction block illustrated in FIG. 4.

Hereinafter, with reference to the accompanying drawings, an error correction method for a high density recording medium and a circuit thereof according to the present invention will be described.

The most common method for increasing the recording capacity of an optical disc is to reduce the area required for recording one bit. Using this method, the conversion from CD disc to DVD disc increased its recording capacity by about 4.8 times. In this case, the wavelength of the laser used in the pick-up should also be reduced due to the characteristics of the optical disk, and thus the error rate is increased during detection, and the number of bits that cannot be error-corrected on the DVD rather than the CD is increased even when the same size scratches are generated on the surface of the disk. Therefore, the error correction method used in the DVD player should be able to correct more errors than the error correction method used in the CD player.

In HD-DVD, a medium that can record more information than this DVD disc, the area required to record 1 bit is reduced to about 1 / 3.36 of DVD. This is so that about 15GB of information can be recorded on one HD-DVD disc. Accordingly, the error correction capability must also be increased. The present invention proposes a method of increasing the number of parity in a codeword as a method of improving error correction capability for an HD-DVD disc, and modifying a format for an error correction block used in a general DVD disc format. Make it applicable to DVD.

3 is a block diagram according to an embodiment of an error correction circuit for a high density recording medium according to the present invention, in which an error correction encoder (denoted ECC: 102) is a diagram for inputting encoded data in the present invention. Arranged in a modified error correction block as shown in Fig. 4, the error correction code is converted from RSs 208, 192, 17 to RSs 221, 192, 30 for a typical DVD disc. Here, RS stands for Reed-Solomon code, 221 is the size of all codewords, 192 is the size of user data among all codewords, and 30 is the number of parity plus 1. .

The interleaver 104 inserts external parity into the last row of each sector of the error correction coded data, and inserts the external parity in sector units after the last sector of the error correction block. The modulator 106 modulates the interleaved data in the interleaver 104 by a predetermined modulation scheme (here 8 to 16 modulation), and the sink inserter 108 has two 32-bit columns in the column direction for the modulated data. Inserts a sync pattern and outputs it for writing to a disc.

4 is a format for error correction block for HD-DVD proposed in the present invention. In the present invention, a method of increasing the number of external parities is applied in order to correct the size of the scratches in the track direction of the disc to about 6.3 mm, which is required by a general DVD. To do this, the external parity requires 12 more bytes in the row direction, but in order to provide convenience when recording / playing the physical disk, the size of the remaining parity sectors should be equal to that of the data sectors. By adding bytes, only 13 bytes of external parity are configured in the format of a general error correction block.

In the first HD-DVD recording format proposed by the present invention, the interval between tracks is 0.4. μ m, the minimum mark length is 0.22 μ Let m be. According to this, the amount of data that can be recorded in the same area as the DVD-ROM disc is calculated as follows.

The recordable area of a disc is the area of the circle π r ² , where r is the radius of the circle

Outer circumference = π (58mm) ² = 0.01056832m ²

Inner circumference = π (24mm) ² = 0.00180956m ²

to be. Therefore, the actual data area must subtract the inner circumference from the outer circumference.

Data area = 0.00875876m ²

to be. here,

Track Pitch Length = 0.4 μ m,

Min Pitch Length = 0.22 μ m = 3T = 3bit,

Area occupied by 3 bits = 0.4 μ m × 0.22 μ m = 8.8e-14m ² ,

1bit area occupied ^{= 8.8e-14m 2/3 =} 2.93e-14m 2,

Recordable Data Area = 0.0087587m ²

Therefore, dividing the data area of the recordable capacity by the area occupied by 1 bit,

0.087587m ² / 2,93e-14m ² = 2.98e + 11 bits

to be. Since this is a value after being modulated by 8 to 16 modulation, it is 2.98e + 11/2 bits when converted, and (2.98e + 11/2) / 8 byte = 18.6 Gbyte when converted in byte units.

The ratio occupied by the error correction parity and the sync pattern rather than the user data in the error correction block used in a general DVD disc is calculated as follows.

Total User Data Volume = 192 × 172 = 33024 bytes,

Parity = 16 × 182 + 192 × 10 = 4832 bytes,

Size of the sink pattern = (208 × 32 × 2) / 8 = 1664 bytes

Therefore,

Total redundancy = 4832 + 1664 = 6496 bytes,

Total amount of data = 33024 + 6496 = 39520 bytes

to be. Since the ratio of total data amount and redundancy amount is 6496/39520 = 16.437%, let X be the total size of redundancy in HD-DVD disc.

6496: 39520 = X: 18.6e + 9

X = 3.057e + 9 bytes

to be. Therefore, the actual recordable user data amount is 18.6e + 9-3.057e + 9 = 15.5 Gbytes.

In addition, since the size of the error correction capability should be able to correct about 6.3 mm in the track direction of the disc, the minimum mark length recorded on the disc = 0.22 μ When m = 3T = 3 bits, the number of bits that can be error corrected is X.

6.3 mm: X = 0.22 μ m: 3bit

X = 85909 bit

to be. 16 to 8 demodulation yields 85909/2 = 42954 bits.

By converting this to byte units, it is 42954/8 = 5369 bytes, and corresponding to the error correction block of the DVD-ROM, there are 182 bytes in the column direction, so the number of rows is 5369/182 = 29.5 lines. Since the sync pattern is missing in the column direction of 182 bytes, the number of parity required for error correction should be calculated in consideration of the sync pattern. In other words, the sink pattern has 64 bits inserted in one row in the column direction, and the sink pattern is 5369 / (182 + 64/8) = 28.2 lines because the sink pattern is predetermined. This value is the number of parities required for correction in error correction in the row direction.

Thus, at least 29 bytes of external error correction must be able to correct. For this purpose, the number of error correction parity in the row direction must be changed. In the present invention, a method of correcting only the number of external parity without changing the size of the user data of the error correction block is applied. In other words, it is optimal to be RS (221, 192, 30).

Then, the size of each data sector and parity sector are the same, so that the interval between sectors is kept constant. This is done so that the start point of each sector can be easily detected during reproduction, or not to miss the start point of the next sector even if the start point of each sector is not detected.

FIG. 5 is a diagram illustrating a result of interleaving the error correction block shown in FIG. 4. The interleaving method of the present invention also follows the general DVD-ROM format, and inserts one line of external parity after the last line of each sector, and the remaining 13 lines (= 29-16) are arranged at the end of the error correction block. do.

On the other hand, in the recording format according to another embodiment of the HD-DVD to which the present invention is applied, the interval between tracks is 0.42. μ m, the minimum mark length is 0.22 μ In the case of m, the format of the error correction block shown in FIG. 4 may be applied.

As described above, the data area that can be recorded in the same area as the DVD-ROM disk is 0.00875876m ² ,

Track Pitch Length = 0.42 μ m,

Min Pitch Length = 0.22 μ m = 3T = 3bit,

Area occupied by 3 bits = 0.42 μ m × 0.22 μ m = 9.24e-14m ² ,

1bit area occupied ^{= 9.24e-14m 2/3 =} 3.08e-14m 2,

Recordable Data Area = 0.0087587m ²

Therefore, dividing the data area of the recordable capacity by the area occupied by 1 bit,

0.087587m ² / 3.08e-14m ² = 2.84e + 11bits

to be. Since this is a value after 8 to 16 modulation, the conversion is 2.84e + 11/2 bits.

(2.84e + 11/2) / 8 byte = 17.777 Gbyte

to be. Since the ratio of the error correction parity and the sync pattern, not the user data, in the DVD-ROM error correction block is as described above, the total user data amount is 33024 bytes, the parity amount is 4832 bytes, and the size of the sync pattern is 1664 bytes. The total redundancy amount is 6496 bytes and the total data amount is 39520 bytes.

X is the size of the total redundancy on an HD-DVD disc.

6496: 39520 = X: 17.777e + 9

X = 2.922e + 9

to be. The actual recordable user data amount is 17.777e + 9-2.922e + 9 = 14.8 Gbytes.

This HD-DVD recording format supports 0.42 between tracks. μ m, the minimum mark length is 0.22 μ Even when m is used, the maximum number of parities required for row correction is 29 bytes. × 182 = 5278 bytes can be error corrected, but if converted to the actual track length of an HD-DVD disc, the sync pattern is the same as a normal DVD-ROM. It is added.

That is, 29 row × (64/8 +182) = 5510 bytes, which translates into bits 5510 × 8 = 44080 bits. 8 to 16 modulation doubles, so 44080 × 2 = 88160 bits. Actual length of 3T is 0.22 μ Since m is set, the error correction capability corresponds to 88160/3 = 29386 minimum marks.

Therefore, the HD-DVD recording format is 0.42 between tracks. μ m (or 0.42 μ m), and the minimum mark length is 0.22 μ If m is the external parity for error correction as 29 bytes, the correctable length is 29386 × 0.22 μ m = 6.5 mm.

In summary, in the present invention, the recording capacity can be increased to 15.5 Gbytes while maintaining compatibility with the existing DVD-ROM in the HD-DVD disc, and the error correction capability required by the current optical disc can be secured. To do this, set the track pitch to 0.74. μ 0.4 in m μ reduce to m, the minimum record mark length to 0.4 μ 0.22 in m μ Use an HD-DVD recording format that reduces to m and increases the minimum external parity size from 16 bytes to 29 bytes to correct 6.3 mm scratches in the track direction. Can be. In addition, the track pitch is set to 0.74 μ 0.42 at m μ reduce to m, the minimum record mark length to 0.4 μ 0.22 in m μ An HD-DVD recording format reduced to m can be used, with a recording capacity of 14.8 GBytes.

The error correction block in which the external parity has been corrected is interleaved with a sector of data and a part of the external parity, and the remaining external parity is arranged in the form of being added after the error correction block as it is, and the size of the added external parity is arranged. It is equal to the size of the data sector.

In the present invention, as the area required for recording one bit decreases in order to increase the recording capacity of the optical disk, the ability of error correction must be increased as well. Presented.

At this time, there is a method of increasing the number of external parity or the number of internal parity, but the present invention only provides a method of increasing the number of external parity only. However, the method of increasing the number of internal parity is also one of the methods of increasing the error correction ability can be easily modified in the method described in the present invention. In addition, when the length required to record 1 bit varies, the range in which the number of additional external parities changes according to the present invention can be easily inferred by using the calculation formula proposed in the present invention.

As described above, the present invention has the effect of increasing the error correction capability of a high-density recording medium capable of recording approximately 15 Gbytes on one end face by increasing parity in codewords while maintaining maximum compatibility with a general DVD disc.

Claims (17)

In the error correction method for high density recording media: (a) determining the size of recordable user data and the size of error correction parity according to the minimum mark length and track pitch length; And (b) generating error correction coded data for the error correction block having the determined size of the error correction parity. The method of claim 1, wherein the minimum mark length is 0.22 μ m, the track pitch length is 0.4 μ m, the recordable user data is about 15.5 GByte, and the error correctable length on the recording medium is about 6.5 mm. The method of claim 1, wherein the minimum mark length is 0.22 μ m, track pitch length is 0.42 μ m, the recordable user data is about 14.8 GByte, and the error correctable length on the recording medium is about 6.5 mm. The method of claim 1, wherein the size of the error correction block is 221 bytes in the total codeword in the row direction, and 182 bytes in the total codeword in the column direction. 5. The error correction method according to claim 4, wherein each sector of the error correction block is 2Kbytes, which is composed of 17 error correction blocks. The error correction method of claim 4, wherein an external parity of the error correction block is 29 bytes, and the user data is capable of error correction up to 29 bytes in a row direction. The error correction method of claim 4, wherein an internal parity of the error correction block is 10 bytes, and codewords in a column direction are compatible with a DVD family such as a DVD-ROM and a DVD-RAM. The method of claim 4, wherein and (c) interleaving the error correction coded data to generate interleaved data. The error correction method of claim 8, wherein in the step (c), a part of the external parity is inserted by the last one row of each sector, and the remaining external parity is arranged at the end of the error correction block. . The method of claim 8, wherein in the step (c), 16 bytes of the external parity are inserted one line at the end of every sector, and the remaining 13 bytes such as the size of the data sector are arranged at the end of the error correction block. Error correction method. In the error correction circuit for high density recording media: An error correction encoder for outputting error corrected encoded data by arranging input data in a corrected error correction block based on the size of recordable user data and the size of error correction parity determined according to the minimum mark length and track pitch length; And And an interleaver for interleaving the error correction coded data to output interleaved data. 12. The apparatus of claim 11, wherein the error corrected coded data is RS (221, 192, 30), where RS is an abbreviation of Reed-Solomon code, 221 is the size of the entire codeword, and 192 is the size of the user data in the codeword. Size, wherein 30 is the number of external parities plus 1; 13. The error correction circuit according to claim 12, wherein an internal parity of the error correction block is 10 bytes, and codewords in a column direction are compatible with DVD families such as DVD-ROM and DVD-RAM. 13. The error correction circuit of claim 12, wherein the interleaver arranges a part of the outer parity by the last row of each sector, and the remaining outer parity at the end of the error correction block. 13. The error correction circuit of claim 12, wherein the interleaver inserts 16 bytes of the external parity one line at the end of each sector and arranges the remaining 13 bytes equal to the size of the data sector at the end of the error correction block. . 12. The method of claim 11, wherein the minimum mark is 0.22 in length. μ m, the track pitch length is 0.4 μ m, the recordable user data is about 15.5 GByte, and the error correction length on the recording medium is about 6.5 mm. 12. The method of claim 11, wherein the minimum mark is 0.22 in length. μ m, track pitch length is 0.42 μ m, the recordable user data is about 14.8 GByte, and the error correction length on the recording medium is about 6.5 mm.