Title of Invention

"MATHOD AND APPARATUS FOR RECORDING DATA ON AN OPTICAL DISC"

Abstract

An optical recording medium, a data recording apparatus, and a data recording method used by the apparatus are provided. In a method for recording data on an optical disc, each of a plurality of error correction code (ECC) blocks is divided into a plurality of partitions. Next, data from the partitions are interleaved so that each of the ECC blocks is alternately and equally selected to generate a recording block. The generated recording block is modulated and recorded on an optical disc. As a result, the optical recording medium, the data recording apparatus, and the data recording method used by the apparatus, which are compatible with the format of a conventional digital versatile disc (DVD) and have higher error correction rates, are provided.

Full Text

Field of the invention The present invention relates to a method and apparatus for recording data on an optical disc. The present invention relates to error correction, and more particularly, to an optical recording medium, a data recording apparatus, and a data recording method used by the apparatus which are capable of recording high density data. 2. Description of the Related Art Digital broadcasting will soon be commonly used in many countries of the world. However, current digital versatile discs (DVDs) have a capacity of 4.7-10 gigabytes, and thus a two-hour movie (about 25 gigabytes) which is received via digital broadcasting cannot be recorded in a disc. As a result, a high density recording medium for recording a digital broadcast having the size of a movie is required. A method for reducing the size of a laser beam used in recording/reading data is a representative example of a method for increasing recording density. The smaller the radius of the laser beam the more densely an information track in which data are recorded can be formed, thereby increasing recording density. However, if only the radius of the laser beam is decreased, the quantity of light used in recording/reading data is also reduced, and the effect caused by damage or dust occurring on the surface of the disc is relatively increased. That is, an error generation rate in recording/reading data is increased. SUMMARY OF THE INVENTION To solve the above problem, it is a first object of the present invention to provide an optical recording medium, a data recording apparatus, and a data recording method used by the apparatus, which have h[gher_errpr correction rates in recording/reading data. It is a second object of the present invention to provide an optical recording medium, a data recording apparatus, and a data recording method used by the apparatus, which are compatible with the format of a conventional digital versatile disc (DVD) and have higher error correction rates. Accordingly, to achieve the above objects, according to one aspect of the present invention, there is provided a method for recording data on an optical disc. The method includes the steps of (a) dividing each of a plurality of error correction code (ECC) blocks into a plurality of partitions, and (b) interleaving data from the partitions so that each of the ECC blocks is alternately and equally selected to generate a recording block. It is preferable that the method further includes the step of (c) rearranging the generated recording block to generate a new recording block, and the generated recording block is rearranged on a sector basis to generate the new recording block in the step (c). It is also preferable that the method further includes the steps of (d) modulating the generated recording block, and (e) recording the modulated recording block. It is also preferable that the step (a) includes the steps of (a11) dividing each of the ECC blocks in a column direction by a predetermined number of bytes into object blocks, and (a12) dividing each of the object blocks in at least one direction of row and column directions by a predetermined number of bytes to generate a plurality of partitions. It is also preferable that the step (b) of interleaving is performed with the same algorithm in units of the object blocks. It is also preferable that the step (a) includes the steps of (a21) obtaining a common divisor d for N1 and N2 when the size of the ECC blocks is N1xN2 bytes, (a22) dividing each of the ECC blocks into units of d bytes in the column direction to generate a number N2/d of object blocks, and (a23) dividing each of the object blocks which are generated by the step (a22) into a number d of portions in the column and row directions to generate a number d x d of partitions. To achieve the above objects, according to another aspect of the present invention, there is provided a method for recording data on an optical disc. The method includes the steps of (a) dividing each of two error correction code (ECC) blocks in row and column directions to generate a plurality of partitions, and (b) interleaving data from the partitions so that each of the ECC blocks is alternately and equally selected to generate a recording block. It is preferable that the data of the partitions are interleaved such that a number 2 x N2 of row-code words are included in the block obtained after interleaving the data in the step (b), and the ECC blocks have row-code words (N1, k1), and column-code words (N2, k2), and the block including 2 x N2 row-code words is converted to generate a recording block which includes a main data region of 2 x (N2-k2) bytes and an outer parity region of 2 x k2 bytes in the step (c), wherein N1 and k1 indicate the length of a code word, respectively, and N2 and k2 indicate the number of a parity, respectively. To achieve the above objects, according to another aspect of the present invention, there is provided an apparatus for recording data on an optical disc. The apparatus includes an error correction code (ECC) encoder for generating a plurality of error correction code (ECC) blocks in which main data are recorded, and an interleaver including a partitioning portion for dividing each of the generated ECC blocks by a first unit in the row direction and by a second unit in the column direction so as to generate a plurality of partitions, a data extracting portion for alternately extracting data of the partitions from each of the ECC blocks, and a recording block generating portion for interleaving the extracted data and generating a recording / block. It is preferable that the apparatus further includes a modulating part for modulating the generated recording block, and a recording part for recording the modulated recording block. It is also preferable that the partitioning portion divides each of the ECC blocks in the column direction by a predetermined number of bytes and divides each of the ECC blocks in the row direction by a predetermined number of bytes to generate a plurality of partitions, and the recording block generating portion sequentially interleaves the extracted data to generate a recording block, and the partitioning portion obtains a common divisor d for N1 and N2 when the size of the ECC blocks is N1xN2 bytes, and then divides each of the ECC blocks by a unit of d bytes in the column direction to generate a plurality of object blocks, and then divides each of the object blocks into a number d of portions in the column and row directions to generate a number d x d of partitions. To achieve the above objects, according to another aspect of the present invention, there is provided an apparatus for recording data on an optical disc. The apparatus includes an error correction code (ECC) encoder for generating two error correction pode (ECC) blocks, and an interleaver for dividing each of the two generated ECC blocks by a first unit in the row direction and by a second unit in the column direction so as to generate a plurality of partitions, alternately extracting data of the plurality of partitions from each of the ECC blocks, and interleaving the extracted data and generating a recording block. It is preferable that the apparatus further includes a modulating part'for modulating the generated recording block, and a recording part for recording the modulated recording block. It is also preferable that the interleaver divides each of the ECC blocks in a column direction by a predetermined number of bytes to generate a plurality of object blocks and divides each of the object blocks in column and row directions by a predetermined number of bytes to generate a plurality of partitions, and the interleaver obtains a common divisor d for N1 and N2 when the size of the ECC blocks is N1xN2 bytes, and then divides each of the ECC blocks by a unit of cTbytes t ; / in the column direction to generate a plurality of object blocks, and then divides each of the object blocks into a number d of portions in the column and row directions to generate a number d x d of partitions, and the data of the partitions are interleaved such that a number 2 x N2 of row-code words are included in the block obtained after interleaving the data, and the ECC encoder generates the ECC blocks having row-code words (N1, k1), and column-code words (N2, k2), and the interleaver converts a block including 2 x N2 row-code words to generate a recording block which includes a main data region of 2 x (N24 To achieve the above objects, according to another aspect of the present invention, there is provided an optical recording medium containing data included in one or more recording blocks. Here, the data from partitions of a plurality of ECC blocks are interleaved in the recording blocks. Particularly, it is preferable that the data from the partitions are interleaved so that each of the ECC blocks is alternately and equally selected. BRIEF DESCRIPTION OF THE DRAWINGS The above objects and advantages of the present invention will become more apparent by describing in detail a preferred embodiment thereof with reference to the attached drawings in which: FIGS. 1A and 1B are block diagrams of a data recording apparatus according a preferred embodiment of the present invention; FIGS. 2A and 2B illustrate the format of error correction code (ECC) blocks which are interleaved according to the present invention; FIG. 3 illustrates the format of a block generated by interleaving of FIG. 2; FIG. 4 illustrates numbers which are allocated to N1/d bytes of data belonging to a partition 1_1; FIG. 5 illustrates a recording block rearranged on the basis of the block of FIG. 3; FIG. 6 is an example of the ECC blocks A and B of FIG. 2; FIG. 7 illustrates the format of the block generated by interleaving of FIG. 5; FIG. 8 illustrates a recording block rearranged on the basis of the block of FIG. 6; FIG. 9 illustrates the largest error that can be corrected by error correction according to the present invention; and FIGS. 10A and 10B are block diagrams of a data reproducing apparatus according to a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIGS. 1A and 1B are block diagrams of a data recording apparatus according a preferred embodiment of the present invention. Referring to FIG. 1 A, the data recording apparatus includes an error correction code (ECC) encoding part 1, a modulating part 3, and a recording part 5. The ECC encoding part 1 includes an ECC encoder 11 and an interleaver 12. The interleaver 12 includes a partitioning portion 121, a data extracting portion 122, and a recording block generating portion 123. The ECC encoder 11 encodes main data with an error-correction-code (ECC). The interleaver 12 interleaves the ECC-encoded main data according to the present invention and generates a recording block. r Interleavingj is done to increase error correction efficiency and is a method for physically distributedly recording contiguous main data in ECC blocks on an optical disc. A burst error can be very effectively corrected by Hnterleavingj . In order to perform r interleaving j according to the present invention, the pa^tipning_gorWooJL2J. divides each of the generated ECC blocks in a row direction and a column direction to generate a plurality of partitions. The data extracting portion 122 alternately extracts the data of the partitions from each of the ECC blocks so that each of the ECC blocks is alternately and equally selected. For example, in a case where there are a number N of ECC blocks, they may be selected in the order of 1, 2, 3,. . . , N-1, N. The recording block generating portion 123 interleaves the extracted data to generate a recording block. A more specific Hnterleavingj method will be described later. The mpdulating part 3 modulates the recording block generated by the ECC encoding part 1 according to a predetermined modulating method. The modulating method used in this embodiment is eight to fourteen modulation plus (EFM+), that is, a method for modulating each byte of the recording block data into a 16 bit code word. The recording part 5 records the modulated recording block on an optical disc 100. When recording the modulated recording block on the optical disc_.lQQ, a channel bit pulse stream which a modulated bit stream is converted into by non return to zero inversion (NRZI) coding according to the embodiment, is recorded. Here, various converting methods for recording the channel bit pulse stream can be used. FIGS. 2A and 2B illustrate the format of ECC blocks which are interleaved according to the present invention. Referring to FIG. 2A, each of ECC blocks A and B consists of N1 bytes of data in a row direction, and N2 bytes of data in a column direction. Row-code words consisting of main data and an inner parity are arranged in a row direction. Here, a predetermined number of row-code words constitute one sector. Therefore, at least one sector is arranged in a column direction, and row-code words having an identifier ID are included in each sector. The row-code words can be obtained by Reed-Solomon Product coding. That is, each row is a RS(N1, m, p) code. Here, N1 is the total size of the code words, m is/ the size of the main data, and p is the number of parity bits plus one bit. Since Reed-Solomon Product coding is good at correcting multi-errors and is used in digital versatile discs (DVD), Reed-Solomon Product coding is selected for compatibility with DVDs. However, the coding method used can be changed when needed. Similarly, the size of the ECC blocks and the number of bytes allocated to the parity can be changed. The identifier ID and a parity for error detection EDC are included in each sector. The address of the main data included in the corresponding sector is recorded in the identifier ID. Thus, the main data can be searched by the identifier ID. Interleaving for constituting a recording block according to the present invention is performed on the basis of the following. As shown in FIG. 2A, first, each of the ECC blocks A and B is divided by a unit of d rows in a column direction. Here, d is a common divisor for N1 and N2. Blocks which are obtained by dividing by a unit of d rows in a column direction are referred to as object blocks shown in FIG. 2B. Interleaving according to the embodiment of the present invention is repeatedly performed by a unit of two object blocks a and b, which belong to the ECC blocks A and B. Referring to FIG. 2B, more specifically, an interleaving algorithm will be described as follows. First, the object blocks a and b are divided into units of 1 byte in the column direction and are divided into units of d bytes in the row direction. As a result, each of the object blocks a and b are divided into a number d x d of partitions, giving a total of 2 x d x d partitions. These partitions are 1_1, 1_2, . . . , 1_2 x d, 2_1, 2_2 2_2 x d d_1, d_2 and d_2 x d. There are N1/d bytes of data in the partitions such as 1_1, 1_2,. . . , 1_2 x d, 2_1, 2_2, . . . , 2_2 x d, . . . , d_1, d_2, . . . , and d_2 x d, which are finally obtained. Next, data are extracted from the partitions in numerical order. That is, first, data are extracted from the partition 1_1, second, from the partition 1_2,..., and (2 x d)-th, from the partition 1_2 x d. Again, (2 x d +1 )-th, data are extracted from the partition 1_1, and (2 x d +2)-th, from the partition 1_2, ..., and (2 x d +2 x d)-th, from the partition 1_2 x d. In this order, all data are extracted from the partitions 1_1. 1_2,.,.. , 1_2 x d, and then, data are alternately extracted from the partitions 2_1,2_2 2_2xd. The above procedure is performed repeatedly in units of object blocks. The recording block generated as a result of performing the above procedure is shown in FIG. 3. Referring to FIG. 3, the block generated according to FIGS. 2A and 2B is comprised of main data of a 2 x (N2-k2) row and an outer parity of a 2 x k2 row. The numbers recorded in the row direction of the recording block represent serial numbers which are allocated to bytes of data existing in each of the partitions. That is, if interleaving is performed, as described with reference to FIG. 2, bytes of data are arranged in the order shown in FIG. 3. The generated block can be rearranged on the basis of a sector of 2KB. Meanwhile, for simplification, a method for numbering serial numbers of the object blocks a and b, will be now described. Since there are N1/d bytes of data in each of the partitions of the object blocks a and b, the following serial numbers are allocated to each of the partitions of the object blocks a and b. Partition 1_1: N1/d of numbers having 1 of a remainder divided by 2 x d among numbers 1_2 x N1, are sequentially arranged. Partition 1_2: N1/d of numbers having 2 of a remainder divided by 2 x d among numbers of 1_2 x N1, are sequentially arranged. Partition 1_2 x d: N1/d of numbers having 0 of a remainder divided by 2 x d among numbers 1_2 x N1, are sequentially arranged. Partition 2_1: N1/d of numbers having 1 of a remainder divided by 2 x d among numbers 2 x N1+1_2 x N1+2 x N1, are sequentially arranged Partition 2_2: N1/d of numbers having 2 of a remainder divided by 2 x d among numbers 2 x N1 +1_2 x N1 +2 x N1, are sequentially arranged. Partition 2_2 x d: N1/d of numbers having 0 of a remainder divided by 2 x d among numbers 2 x N1 +1_2 x N1 +2 x N1, are sequentially arranged. Partition d_1: N1/d of numbers having 1 of a remainder divided by 2 x d among numbers (d_1) x 2 x N1 +1_d x 2 x N1, are sequentially arranged. Partition d_2: N1/d of numbers having 2 of a remainder divided by 2 x d among numbers (d_1) x 2 x N1+1_d x 2 x N1, are sequentially arranged. Partition d_2 x d: N1/d of numbers having 0 of a remainder divided by 2 x d among numbers (d_1) x 2 x N1 +1_d x 2 x N1, are sequentially arranged. ' This is generalized as following: m_n: N1/d of numbers having n of a remainder divided by 2 x d among numbers of (m-1)x2 xN1+1_mx2x N1 is n, are sequentially arranged. Referring to FIG. 4, for example, numbers such as 1, 1+2d, 1+4d,..., 1+2N1-4d, and 1+2N1-2d , are sequentially allocated to N1/d bytes of data belonging to the partition 1_1. That is, there are N1/d bytes of data in the partition 1_1, 1 is allocated to a first byte of the N1/d bytes of data, 1 +2d to a second byte of the N1/d bytes of data, 1+4d to a third byte of the N1/d bytes of data,..., 1+2N1-4d to a {(N1/d)-1}-th byte of the N1/d bytes of data, and 1+2N1-2d to a (N1/d)-th byte of the N1/d bytes of data. FIG. 5 illustrates a recording block rearranged on the basis of the block of FIG. 3. Referring to FIG. 5, 2 x (N2-k2)/ 32 rows are extracted from the block of FIG. 3, and arranged, and 2 x k2/32 rows are extracted from the outer parity and arranged, thereby forming one sector. The number of sectors generated by the above procedure is 32 in total. The reason for forming 32 sectors is that one error correction code (ECC) block in DVDs is comprised of 16 sectors. In other words, compatibility with DVDs is considered. The range of a burst error correction which can be corrected by Reed-Solomon Product codes in conventional DVDs is 16 rows x 182 bytes + 10 bytes, that is, 2,922 bytes. FIG. 6 is an example of the ECC blocks A and B of FIG. 2. Referring to FIG.6, the ECC blocks A and B denote a case where N1=182 bytes, N2=208 bytes, and d=2. In this case, the recording block according to the present invention is generated by interleaving described below. First, each of the ECC blocks A and B is divided into object blocks in a unit of 2 rows in a row direction. As a result, a total of eight partitions such as and, exist in the object blocks a and b. Next, first data are extracted from the partition, second data are extracted from the partition (3), third data are extracted from the partition , and fourth data are extracted from the partition (8). Again, fifth data are extracted from the partition CD, sixth data are extracted from the partition , seventh data are extracted from the partition and eighth data are extracted from the partition . In this way, after extracting all data from the partitions , again, data are alternately extracted from the partitions and The above procedure is performed repeatedly in a unit of 2 rows. The recording block generated as a result of performing the above procedure is shown in FIG. 7. Referring to FIG. 7, the recording block generated according to FIG. 5 is comprised of 384 rows of data and an outer parity of 32 rows. Similarly, numbers shown in FIG. 7 represent serial numbers which are allocated to bytes of data, as described with reference to FIGS. 3 and 4. Meanwhile, the generated recording block can be rearranged on a sector basis. FIG. 8 illustrates a recording block rearranged on the basis of the block of FIG. 7. Referring to FIG. 8, 12 rows are extracted from a main data region included in the block of FIG. 7 and arranged, and 1 row is extracted from the outer parity region and arranged, thereby forming one sector. The number of sectors generated by the above procedure is 32 in total. Since one error correction code (ECC) block in the DVD is comprised of 16 sectors, compatibility with DVDs is considered. FIG. 9 illustrates the largest error that can be corrected by error correction according to the present invention. For example, the largest error that can be corrected by error correction used in RS(182, 172, 11) x RS(208, 192, 17) is decided as below. Referring to FIG. 9, first, in a case where errors occur in 31 consecutive rows and errors of each 20 bytes occur in both head and tail of the 31 consecutive rows, in total, errors of 40 bytes, an outer parity of 3 rows of the errors is converted into an error of 2 rows in the recording block obtained by interleaving according to the present invention, and the main data of 28 rows of the errors are converted into an error of 14 rows in the recording block obtained by interleaving according to the present invention, and thus, in total, a code of16rows can be corrected by the outer parity. Also, since an error of 20 bytes occurring at the beginning of 31 rows results in an error of 2 rows respectively consisting of one 5 bytes in the recording blocks a and b, the error of 20 bytes can be corrected by the internal parity. Also, an error of 20 bytes occurring at the end of 31 rows results in an error of 2 rows respectively consisting of one 5 bytes in the recording blocks a and b, and thus can be corrected by the inner parity. Thus, in total, 182 bytes x 31 +40 bytes = 5, 682 bytes are corrected. In this way, according to this embodiment of the present invention, interleaving with blocks is performed using two conventional ECC blocks, and interleaving with code words in each block is performed to generate the recording block. As a result, the burst error is distributed into two regions, and the correction ability of the inner parity by interleaving with code words is quadrupled. Meanwhile, in the above-mentioned embodiment, a method for interleaving two ECC blocks was already described, but it is also possible to apply the method for interleaving to more than two ECC blocks. That is, a common divisor between more than two ECC blocks can be obtained, and then, each ECC block can be divided into a plurality of partitions on the basis of the row of the obtained common divisor. Next, a part of data, which are included in the divided plurality of partitions, are extracted from the partitions, thereby interleaving the data. The extraction of the data is performed so that each ECC block is alternately and equally selected. The recording block obtained by interleaving can be consecutively recorded as it is or after being rearranged on a sector basis. FIGS. 10A and 10B are block diagrams of a data reproducing apparatus according to the present invention. Referring to FIG. 10A, the data reproducing apparatus includes a reading part 13, a demodulating part 12, and an ECC decoding part 11. The reading part 13 reads data from an optical disc 900 on which data are recorded according to the present invention. The demodulating part 12 demodulates the read data. The demodulating method used depends on the modulating method. The ECC decoding part 11 ECC-decodes the demodulated data, that is, a recording block. More specifically, referring to FIG. 10B, the ECC decoding part 11 includes a deinterleaver 111 and an ECC decoder 112. The deinterleaver 111 deinterleaves the recording block in the order reverse to the interleaver 12 of FIG. 1B to generate a plurality of error correction code (ECC) blocks. The ECC decoder 112 decodes the demodulated data into main data with an ECC, which are used in the generated ECC block, and outputs the main data. As described above, according to the present invention, the optical recording medium, the data recording apparatus, and the data recording method used by the apparatus, which are compatible with the format of a conventional digital versatile disc (DVD) and have higher error correction rates, are provided. While this invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. WE CLAIM: 1. An apparatus for recording data on an optical disc (100), the said apparatus comprising, characterized by: an error correction code (ECC) encoder (11) for generating a plurality of error correction code (ECC) blocks in which main data are recorded; and an interleaver (12) including a partitioning portion (121) for dividing each of the generated ECC blocks by a first unit in the row direction and by a second unit in the column direction so as to generate a plurality of partitions, a data extracting portion (122) for alternately extracting data of the partitions from each of the ECC blocks, a recording block generating portion (123) for interleaving the extracted data and generating a recording block, a modulating part (3) for modulating the generated recording block; and a recording part (5) for recording the modulated recording block. 2. The apparatus as claimed in claim 1, wherein the partitioning portion(121) divides each of the ECC blocks in the column direction by a predetermined number of bytes and divides each of the ECC blocks in the row direction by a predetermined number of bytes to generate a plurality of partitions. 3. The apparatus as claimed in claim 1, wherein the recording block generating portion (123) sequentially interleaves the extracted data to generate a recording block. 4. The apparatus as claimed in claim 1, wherein the said partitioning portion (121) comprises obtaining a common divisor d of Nl and N2 when the size of the ECC blocks is Nl X N2 bytes, and then dividing each of the ECC blocks by a unit of d ytes in the column direction for generating a plurality of object blocks, and then dividing each of the object blocks into a number d of portions in the column and row directions for generating a number d x d of partitions.

Documents:

1150-del-2001-abstract.pdf

1150-del-2001-claims.pdf

1150-del-2001-correspondence-others.pdf

1150-del-2001-correspondence-po.pdf

1150-del-2001-description (complete).pdf

1150-del-2001-drawings.pdf

1150-del-2001-form-1.pdf

1150-del-2001-form-13.pdf

1150-del-2001-form-18.pdf

1150-del-2001-form-2.pdf

1150-del-2001-form-3.pdf

1150-del-2001-form-5.pdf

1150-del-2001-petition-137.pdf