Fixed pattern detection apparatus
First Claim
1. A device for detecting a fixed pattern, said device being fed with received signals with a pattern of a length of N chips, said received signals being obtained on dividing and re-arraying each of K symbols in terms of a chip period as a unit, K being a preset positive integer, each of said symbols being spread with a spread code at a rate of M chips per symbol, M being a preset positive integer, and on repeatedly inserting into the re-arrayed symbols a signature pattern of a length K having one chip period as a unit, by M times, where N=K×
- M, said signature pattern being detected from said received signal, said device comprising;
first-stage correlators taking correlation between M received signals spaced apart from one another by every K chips, and M spread code sequences obtained on jumping a spread code sequence of a length N by every Kth chip to output correlation values associated with K signatures, respectively; and
second-stage correlators taking correlation between the correlation values associated with K signatures output by said first-stage correlators and a pre-defined signature pattern.
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Abstract
A fixed pattern detection device in which the device is fed as a received signal with a pattern of a length of N chips. The received signal is obtained by dividing and re-arraying each of K (integer) symbols in terms of a chip period as a unit, each symbol being spread with the spread code (PN) at a rate of M (integer) chips per symbol, and on repeatedly inserting into the re-arrayed symbols a signature pattern of a length K having one chip period as a unit, by M times, where N=K×M. The device includes first-stage correlators taking correlation between M received signals and M spread code sequences obtained on decimating a spread code sequence of a length N, and a second stage correlators taking correlation between the correlation values associated with K signatures output by the first-stage correlators and a pre-defined signature pattern.
68 Citations
14 Claims
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1. A device for detecting a fixed pattern, said device being fed with received signals with a pattern of a length of N chips, said received signals being obtained on dividing and re-arraying each of K symbols in terms of a chip period as a unit, K being a preset positive integer, each of said symbols being spread with a spread code at a rate of M chips per symbol, M being a preset positive integer, and on repeatedly inserting into the re-arrayed symbols a signature pattern of a length K having one chip period as a unit, by M times, where N=K×
- M, said signature pattern being detected from said received signal, said device comprising;
first-stage correlators taking correlation between M received signals spaced apart from one another by every K chips, and M spread code sequences obtained on jumping a spread code sequence of a length N by every Kth chip to output correlation values associated with K signatures, respectively; and
second-stage correlators taking correlation between the correlation values associated with K signatures output by said first-stage correlators and a pre-defined signature pattern. - View Dependent Claims (2, 3, 4, 5, 13)
- M, said signature pattern being detected from said received signal, said device comprising;
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6. A device for detecting a fixed pattern, said device being fed a received signal with a pattern of a length of N chips, said received signal being obtained on dividing and re-arraying each of a plurality of K symbols in terms of a chip period as a unit, each of said symbols being spread with a spread code at a rate of M chips per symbol, M being a preset positive integer, and on repeatedly inserting into the re-arrayed symbols a signature pattern of a length K having one chip period as a unit, by M times, where N=K×
- M, said signature pattern being detected from said received signals, said device comprising;
a received signal storage memory transiently storing received signals for at least N+L chips where L, which is an integer divisible by K, denotes an indefinite time range during which there exists said signature pattern;
a spread code generator generating a spread code;
a spread code re-arraying unit jumping and re-arraying the spread code generated by said spread code generator;
a received signal storage memory controller controlling readout from said received signal storage memory;
first-stage correlators comprised of K juxtaposed correlator blocks, each block being of an M chip length;
K spread code shift registers storing the spread code sequence re-arrayed by said spread code re-arraying unit to shift-output said spread code sequence to said K correlator blocks, respectively, of said first-stage correlators;
each of said correlator blocks of said first-stage correlators being fed with a spread code sequence from the spread code shift register associated with each of said correlator blocks, each of said correlator blocks outputting a correlation value of the received signal read out from said received signal storage memory and said spread code sequence;
a correlation value storage memory storing the correlation value output from said first stage correlators;
a correlation value storage memory controller controlling writing of the correlation value output from the first-stage correlators and reading out of the correlation value from said correlation value storage memory;
a signature pattern storage unit storing and holding a preset signature pattern;
second-stage correlators calculating correlation values between the correlation values read out by said correlation value storage memory controller and said signature pattern stored in said signature pattern storage unit; and
a signature detector detecting the signature from the correlation value output from said second-stage correlators to output a fixed pattern detection signal. - View Dependent Claims (7, 8, 9, 10, 11, 12)
- M, said signature pattern being detected from said received signals, said device comprising;
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14. A spread spectrum communication apparatus comprising a detection device for detecting a signature pattern from a received signal, said detection device being fed with received signals with a pattern of a length of N chips, wherein signature pattern of a length K with a one-chip period as a unit is repeatedly inserted M times, said signature pattern, being obtained on dividing and re-arraying each signature of K symbols each being spread with the spread code at a rate of M chips per symbol, said device comprising:
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first-stage correlators taking correlation between M received signals spaced apart from one another at every K chips, and M spread code sequences obtained on decimating a spread code sequence of a length N at every K chips to output correlation values associated with K signatures; and
second-stage correlators taking correlation between the correlation values associated with K signatures output by said first-stage correlators and a pre-defined signature pattern.
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Specification