IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0829426
(2010-07-02)
|
등록번호 |
US-8504900
(2013-08-06)
|
발명자
/ 주소 |
|
출원인 / 주소 |
|
대리인 / 주소 |
Mendelsohn, Drucker & Associates, P.C.
|
인용정보 |
피인용 횟수 :
0 인용 특허 :
50 |
초록
▼
A communication system (e.g., a hard drive) having a random-access memory (RAM) for storing trapping-set (TS) information that the communication system generates on-line during a special operating mode, in which low-density parity-check (LDPC)-encoded test codewords are written to a storage medium a
A communication system (e.g., a hard drive) having a random-access memory (RAM) for storing trapping-set (TS) information that the communication system generates on-line during a special operating mode, in which low-density parity-check (LDPC)-encoded test codewords are written to a storage medium and then read and decoded to discover trapping sets that appear in candidate codewords produced by an LDPC decoder during decoding iterations. The discovered trapping sets are filtered to select a subset of trapping sets that satisfy specified criteria. The discovery and filtering of trapping sets is performed based on error vectors that are calculated using the a priori knowledge of original test codewords. The TS information corresponding to the selected subset is stored in the RAM and accessed as may be necessary to break the trapping sets that appear in candidate codewords produced by the LDPC decoder during normal operation of the communication system.
대표청구항
▼
1. A communication system, comprising: a decoder;a memory; anda trapping-set filter adapted to (i) generate trapping-set information based on one or more error vectors corresponding to one or more candidate codewords produced by the decoder in a process of decoding a first set of read signals corres
1. A communication system, comprising: a decoder;a memory; anda trapping-set filter adapted to (i) generate trapping-set information based on one or more error vectors corresponding to one or more candidate codewords produced by the decoder in a process of decoding a first set of read signals corresponding to a first codeword stored in a storage medium and (ii) supply the generated trapping-set information for storage in the memory; andwherein the system is configured to access the generated trapping-set information in the memory to break a trapping set encountered by the decoder in a process of decoding a second set of read signals corresponding to a second codeword stored in the storage medium. 2. The system of claim 1, wherein the trapping-set filter comprises an error-vector generator adapted to generate the one or more error vectors, wherein each error vector is generated by applying an exclusive OR function to the first codeword and a corresponding candidate codeword produced by the decoder, wherein the first codeword is a reference codeword. 3. The system of claim 2, wherein the error-vector generator is configured to receive the first codeword from an encoder via a path that bypasses the storage medium. 4. The system of claim 2, wherein the error-vector generator is configured to obtain the first codeword from a reference list of codewords, wherein both an encoder and the trapping-set filter possess respective copies of said reference list. 5. The system of claim 2, further comprising a post-processor operatively coupled to the decoder and configured to (i) recover the first codeword based on the candidate codeword and (ii) supply the recovered first codeword to the error-vector generator for the exclusive OR function. 6. The system of claim 2, wherein the trapping-set filter further comprises: an indexing module adapted to process the one or more error vectors generated by the error-vector generator to generate index data corresponding to trapping sets encountered by the decoder in the process of decoding the read signals;a trapping-set buffer adapted to store the index data generated by the indexing module; anda trapping-set selector adapted to identify a subset of the index data for transfer from the trapping-set buffer to the memory as part of the generated trapping-set information. 7. The system of claim 1, wherein, for each failed decoding operation, the trapping-set filter is configured to generate trapping-set information corresponding to a maximum of N1 stable trapping sets, N2 transient trapping sets, and N3 minimum-weight trapping sets, where N1, N2, and N3 are predetermined positive integers. 8. The system of claim 1, wherein the memory comprises: a trapping-set read-only memory that is loaded with off-line-generated trapping-set information; anda trapping-set random-access memory adapted to store the generated trapping-set information supplied by the trapping-set filter. 9. The system of claim 1, further comprising: an encoder adapted to encode original information words to generate corresponding channel-input codewords;a write processor adapted to convert the channel-input codewords into corresponding write signals and apply said write signals to the storage medium; anda channel detector adapted to sense the storage medium to obtain the read signals, convert the read signals into corresponding sets of log-likelihood-ratio values, and supply said log-likelihood-ratio values to the decoder, wherein the decoder is adapted to recover the codewords stored in the storage medium based on said log-likelihood-ratio values and the generated trapping-set information supplied to the memory by the trapping-set filter. 10. The system of claim 9, wherein: the encoder is a Low-Density Parity Check encoder;the decoder is a corresponding Low-Density Parity Check decoder; andthe storage medium is a hard-disk platter. 11. A communication system, comprising: a decoder;a memory; anda trapping-set filter adapted to (i) generate trapping-set information based on error vectors corresponding to candidate codewords produced by the decoder in a process of decoding read signals received from a storage medium and (ii) supply the generated trapping-set information for storage in the memory,wherein the trapping-set filter comprises an error-vector generator adapted to generate the error vectors, wherein each error vector is generated by applying an exclusive OR function to a reference codeword and a corresponding candidate codeword produced by the decoder; andwherein the error-vector generator is configured to obtain the reference codeword from a reference list of codewords, wherein both an encoder and the trapping-set filter possess respective copies of said reference list. 12. A communication system, comprising: a decoder;a memory; anda trapping-set filter adapted to (i) generate trapping-set information based on error vectors corresponding to candidate codewords produced by the decoder in a process of decoding read signals received from a storage medium and (ii) supply the generated trapping-set information for storage in the memory, wherein the trapping-set filter comprises: an error-vector generator adapted to generate the error vectors, wherein each error vector is generated by applying an exclusive OR function to a reference codeword and a corresponding candidate codeword produced by the decoder;an indexing module adapted to process the error vectors generated by the error-vector generator to generate index data corresponding to trapping sets encountered by the decoder in the process of decoding the read signals;a trapping-set buffer adapted to store the index data generated by the indexing module; anda trapping-set selector adapted to identify a subset of the index data for transfer from the trapping-set buffer to the memory as part of the generated trapping-set information. 13. The system of claim 12, wherein the trapping-set selector is adapted to identify said subset of the index data based on the error vectors generated by the error-vector generator. 14. The system of claim 12, wherein the trapping-set selector comprises a plurality of serially connected error-vector buffers, wherein: a first error-vector buffer of the plurality is configured to receive an error vector from the error-vector generator; andeach of one or more additional error-vector buffers of the plurality is configured to receive an error vector previously stored in the error-vector buffer that immediately precedes that additional error-vector buffer in the series. 15. The system of claim 14, wherein the trapping-set selector further comprises: a logic circuit adapted to process the error vectors stored in the plurality of error-vector buffers to generate a plurality of indicator signals; anda trapping-set-identification-information buffer adapted to receive and store identification information that identifies the subset of the index data, wherein the trapping-set selector is adapted to generate said identification information based on the plurality of indicator signals. 16. The system of claim 12, wherein the trapping-set filter further comprises a redundancy filter adapted to prevent trapping-set information already stored in the memory from being transferred from the trapping-set buffer to the memory. 17. The system of claim 12, wherein the indexing module comprises a first index memory and a second index memory, each adapted to store index data corresponding to a trapping set encountered by the decoder in one iteration of the decoding process, wherein: the first index memory is configured to transfer index data stored therein to the trapping-set buffer while the second index memory is receiving different index data being generated by the indexing module, and vice versa. 18. The system of claim 12, wherein the trapping-set buffer comprises a first buffer portion and a second buffer portion, wherein: the first buffer portion is configured to transfer a subset of the index data stored therein to the memory while the second buffer portion is receiving different index data from the indexing module, and vice versa.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.