DETECTING CODEWORDS IN SOLID-STATE STORAGE DEVICES
First Claim
1. A method for detecting codewords in solid-state storage devices, the method comprising the steps of:
- obtaining, by a processor of the computer system, respective read signals by reading memory cells that stores a group of N-symbol codewords, wherein each of said read signals comprises N signal components corresponding to respective symbols of said codeword;
producing, by the processor, an ordered read signal by ordering said components of each of said read signals according to a signal level;
producing, by the processor, an average read signal by averaging corresponding components of said ordered read signals;
determining, by the processor, a reference signal level that corresponds to each of q levels of said memory cells in relation to said average read signal with predefined probabilities of each symbol value occurring at each symbol position in said codeword, wherein said symbols of said codeword are ordered according to said symbol value; and
detecting, by the processor, said codeword corresponding to each of said read signal in relation to said reference signal levels;
wherein each of said codewords is a permutation of an N-symbol vector in a predefined set of said N-symbol vectors;
wherein each of said symbols of each said codeword has one of q symbol values; and
wherein said symbols are stored in respective q-level cells of solid state memory, where N≧
q>
2.
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Abstract
A method for detecting codewords in solid-state storage devices. The method includes the steps of: obtaining respective read signals by reading memory cells that stores a group of codewords, where each of the read signals includes N signal components corresponding to respective symbols of the codeword; producing an ordered read signal by ordering the components of each of the read signals according to a signal level; producing an average read signal by averaging corresponding components of the ordered read signals; determining a reference signal level that corresponds to each of q levels of the memory cells in relation to the average read signal with predefined probabilities of each symbol value occurring at each symbol position in the codeword, where the symbols of the codeword are ordered according to the symbol value; and detecting the codeword corresponding to each of the read signal in relation to the reference signal levels.
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Citations
15 Claims
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1. A method for detecting codewords in solid-state storage devices, the method comprising the steps of:
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obtaining, by a processor of the computer system, respective read signals by reading memory cells that stores a group of N-symbol codewords, wherein each of said read signals comprises N signal components corresponding to respective symbols of said codeword; producing, by the processor, an ordered read signal by ordering said components of each of said read signals according to a signal level; producing, by the processor, an average read signal by averaging corresponding components of said ordered read signals; determining, by the processor, a reference signal level that corresponds to each of q levels of said memory cells in relation to said average read signal with predefined probabilities of each symbol value occurring at each symbol position in said codeword, wherein said symbols of said codeword are ordered according to said symbol value; and detecting, by the processor, said codeword corresponding to each of said read signal in relation to said reference signal levels; wherein each of said codewords is a permutation of an N-symbol vector in a predefined set of said N-symbol vectors; wherein each of said symbols of each said codeword has one of q symbol values; and wherein said symbols are stored in respective q-level cells of solid state memory, where N≧
q>
2. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An apparatus for detecting solid state storage devices, the apparatus comprising:
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a memory controller configured to obtain read signals by reading memory cells that store a group of codewords, wherein each of said read signal comprises N signal components corresponding to said symbols of said codeword; and a codeword detector configured to; produce an ordered read signal by ordering said components of each of said read signals according to a signal level; produce an average read signal by averaging corresponding components of said ordered read signals; determine a reference signal level that corresponds to each of q levels of said memory cells in relation to said average read signal with predefined probabilities of each symbol value occurring at each symbol position in said codeword, wherein said symbols of said codeword are ordered according to said symbol value; and detect said codeword corresponding to each of said read signal in relation to said reference signal levels; wherein each of said codewords is a permutation of an N-symbol vector in a predefined set of said N-symbol vectors; wherein each of said symbols of each said codeword has one of q symbol values; and wherein said symbols are stored in respective q-level cells of solid state memory, where N≧
q>
2.
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15. A solid-state storage device, comprising:
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a solid-state memory having q-level cells, wherein q>
2;a writing apparatus for writing N-symbol codewords in said solid-state memory where N≧
q;wherein each of said N-symbol codewords is a permutation of an N-symbol vector of a predefined set of said N-symbol vectors; wherein said each of said symbols of each said codeword has one of q symbol values; and wherein said symbols are stored in respective q-level cells; and a codeword detector configured to; produce an ordered read signal by ordering said components of each of said read signals according to a signal level; produce an average read signal by averaging corresponding components of said ordered read signals; determine a reference signal level that corresponds to each of q levels of said memory cells in relation to said average read signal with predefined probabilities of each symbol value occurring at each symbol position in said codeword, wherein said symbols of said codeword are ordered according to said symbol value; and detect said codeword corresponding to each of said read signal in relation to said reference signal levels.
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Specification