US6549664B1
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Sparse modulation codes for holographic data storage
Assignee: Research Investment Network Inc
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Filing: 1999-06-30
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Granted: 2003-04-15
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Expires: 2019-06-30
Abstract
Abstract A method for storing data in a holographic storage medium comprises the steps of dividing a bit stream of binary data into data groups, encoding the data groups as binary patterns, and storing the binary patterns holographically as data pages. Each binary pattern comprises channel bits, wherein the number of “off” channel bits is greater than the number of “on” channel bits. To retrieve information from the storage medium, the medium is illuminated and resultant light signals are gathered. The light signals are converted to the binary patterns, and the binary patterns are converted to the data groups. Binary patterns stored in the storage medium only slightly perturb subsequent reading and writing of data, since the patterns have fewer “on” channel bits than “off” channel bits.
Inventors
- 👤 Andrew J. Daiber
- 👤 Robert R. McLeod
- 👤 Ray Snyder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:55
CPC Classifications
G; G03; G03H; G03H1/00; G03H1/26; G11; G11B; G11B7/00; G11B7/004; G11B7/0065
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
95 words
A method of encoding binary data for storage in a holographic storage medium, said method comprising the steps of: a) forming a series of data groups from said binary data; b) converting said data groups into a number of binary patterns, wherein each of said binary patterns comprises channel bits, and wherein a k th of said binary patterns has m k “on” channel bits and n k −m k “off” channel bits, wherein m k <n k /2; and c) storing said binary patterns as a plurality of pages in said holographic storage medium.
Claim 2
Independent Claim
95 words
A method of encoding binary data for storage in a holographic storage medium, said method comprising the steps of: a) forming a series of data groups from said binary data; b) converting said data groups into a number of binary patterns, wherein each of said binary patterns comprises channel bits, and wherein a k th of said binary patterns has m k “on” channel bits and n k −m k “off” channel bits, wherein m k <n k /2; and c) storing said binary patterns as a plurality of pages in said holographic storage medium.
Claim 3
Dependent Claim
29 words
The method of claim 1 , wherein a k th of said data groups comprises b k binary bits, and wherein n k -choose-m k ≧2 b k .
Claim 4
Dependent Claim
23 words
The method of claim 1 , wherein for every value of k between 1 and said number of binary patterns, m k =m.
Claim 5
Dependent Claim
33 words
The method of claim 3 , wherein: a) a sparseness is an average value of n k /m, and b) said sparseness is selected to maximize a storage capacity of said storage medium.
Claim 6
Dependent Claim
12 words
The method of claim 4 wherein said sparseness is equal to 3.
Claim 7
Dependent Claim
26 words
The method of claim 1 , wherein the step of converting said data groups into said binary patterns comprises the step of using a lookup table.
Claim 8
Dependent Claim
27 words
The method of claim 1 , wherein the step of forming said series of said data groups comprises the step of error correction encoding said binary data.
Claim 9
Dependent Claim
27 words
The method of claim 1 , wherein the step of forming said series of said data groups comprises the step of reordering bytes of said binary data.
Claim 10
Dependent Claim
18 words
The method of claim 1 , further comprising the step of storing reference marks in said storage medium.
Claim 11
Dependent Claim
66 words
A holographic storage medium comprising: a plurality of regions of perturbations in an index of refraction of said storage medium, wherein said regions correspond to a plurality of pages comprising binary patterns of channel bits, and wherein said binary patterns have fewer “on” channel bits than “off” channel bits; and additional regions of perturbations in said index of refraction, said additional regions corresponding to reference marks.
Claim 12
Dependent Claim
66 words
A holographic storage medium comprising: a plurality of regions of perturbations in an index of refraction of said storage medium, wherein said regions correspond to a plurality of pages comprising binary patterns of channel bits, and wherein said binary patterns have fewer “on” channel bits than “off” channel bits; and additional regions of perturbations in said index of refraction, said additional regions corresponding to reference marks.
Claim 13
Dependent Claim
21 words
The medium of claim 10 wherein each of said binary patterns has m “on” channel bits and n−m “off” channel bits.
Claim 14
Independent Claim
122 words
A method of decoding binary data stored as pages in a holographic storage medium, said method comprising the steps of: a) illuminating said storage medium with an address beam; b) detecting a plurality of light signals induced by said address beam; c) using said detected light signals to form a data array; d) identifying a data sector comprising n elements of said data array, wherein n>2; e) identifying the m largest values of said n elements as “on” channel bits, wherein m is a number less than n/2; and identifying the remaining n−m values of said n elements as “off” channel bits, thereby obtaining a binary pattern corresponding to said data sector; and f) converting said binary pattern to a binary number.
Claim 15
Independent Claim
122 words
A method of decoding binary data stored as pages in a holographic storage medium, said method comprising the steps of: a) illuminating said storage medium with an address beam; b) detecting a plurality of light signals induced by said address beam; c) using said detected light signals to form a data array; d) identifying a data sector comprising n elements of said data array, wherein n>2; e) identifying the m largest values of said n elements as “on” channel bits, wherein m is a number less than n/2; and identifying the remaining n−m values of said n elements as “off” channel bits, thereby obtaining a binary pattern corresponding to said data sector; and f) converting said binary pattern to a binary number.
Claim 16
Dependent Claim
71 words
The method of claim 12 , further comprising the steps of: a) identifying additional data sectors of said data array, and b) converting said additional data sectors to additional binary patterns, wherein a k th of said additional binary patterns comprises m k “on” channel bits and n k −m k “off” channel bits; wherein an average value of n k /m k optimizes a storage capacity of said storage medium.
Claim 17
Dependent Claim
26 words
The method of claim 12 , wherein said step of converting said binary pattern to a binary number comprises the step of using a lookup table.
Claim 18
Dependent Claim
48 words
The method of claim 12 , further comprising the steps of: a) identifying additional data sectors of said data array; b) converting said additional data sectors into additional binary numbers; c) unshuffling said binary number and said additional binary numbers, to obtain a reordered sequence of binary numbers.
Claim 19
Dependent Claim
20 words
The method of claim 15 , further comprising the step of error correction decoding said reordered sequence of binary numbers.
References Cited (Backward Citations)
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| 3.5 Years (Year 4) | 2006-04-14 | 2006-10-14 | 2007-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2010-04-14 | 2010-10-14 | 2011-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2014-04-14 | 2014-10-14 | 2015-04-15 | $7700.00 | Window Closed / Lapsed |