Combined distortion estimation and error correction coding for memory devices
First Claim
1. A method for operating a memory device, comprising:
- encoding data using an Error Correction Code (ECC) and storing the encoded data as first analog values in respective analog memory cells of the memory device;
after storing the encoded data, reading from the memory cells of the memory device in which the encoded data were stored respective second analog values, at least some of which differ from the respective first analog values;
estimating a distortion that is present in the second analog values;
computing error correction metrics with respect to the second analog values responsively to the estimated distortion; and
processing the second analog values using the error correction metrics in an ECC decoding process, so as to reconstruct the data.
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Abstract
A method for operating a memory device (24) includes encoding data using an Error Correction Code (ECC) and storing the encoded data as first analog values in respective analog memory cells (32) of the memory device. After storing the encoded data, second analog values are read from the respective memory cells of the memory device in which the encoded data were stored. At least some of the second analog values differ from the respective first analog values. A distortion that is present in the second analog values is estimated. Error correction metrics are computed with respect to the second analog values responsively to the estimated distortion. The second analog values are processed using the error correction metrics in an ECC decoding process, so as to reconstruct the data.
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Citations
88 Claims
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1. A method for operating a memory device, comprising:
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encoding data using an Error Correction Code (ECC) and storing the encoded data as first analog values in respective analog memory cells of the memory device; after storing the encoded data, reading from the memory cells of the memory device in which the encoded data were stored respective second analog values, at least some of which differ from the respective first analog values; estimating a distortion that is present in the second analog values; computing error correction metrics with respect to the second analog values responsively to the estimated distortion; and processing the second analog values using the error correction metrics in an ECC decoding process, so as to reconstruct the data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A method for operating a memory device, comprising:
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storing data as first analog values in respective analog memory cells of the memory device; after storing the data, reading multiple instances of second analog values from the respective memory cells, each of the instances read by comparing the second analog values to a respective decision threshold; estimating a distortion that is present in the second analog values; and processing the multiple instances of the second analog values responsively to the estimated distortion, so as to reconstruct the data. - View Dependent Claims (43)
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44. Apparatus for retrieving data that has been encoded using an Error Correction Code (ECC) and stored as first analog values in respective analog memory cells of a memory device, the apparatus comprising:
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a reading unit, which is arranged to read from the analog memory cells of the memory device in which the encoded data were stored respective second analog values, at least some of which differ from the respective first analog values; a signal processing unit, which is arranged to estimate a distortion that is present in the second analog values and to compute error correction metrics with respect to the second analog values responsively to the estimated distortion; and a decoder, which is arranged to process the second analog values using the error correction metrics, so as to decode the ECC and reconstruct the data. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87)
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88. Apparatus for retrieving data that has been stored as first analog values in respective analog memory cells of a memory device, the apparatus comprising:
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a reading unit, which is arranged to read multiple instances of second analog values from the respective memory cells, each of the instances read by comparing the second analog values to a respective decision threshold; and a signal processing unit, which is arranged to estimate a distortion that is present in the second analog values and to process the multiple instances of the second analog values responsively to the estimated distortion, so as to reconstruct the data.
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Specification