Apparatus and methods for signal recovery in a digital communication system
First Claim
1. A method of recovering transmitted signals in a digital communications system, comprising the steps of:
- (a) obtaining n samples of a received signal for a respective time p, p-1, p-2, . . . , p-j and digitizing the n samples to provide (j+1) sets of n digitized samples;
(b) providing (j+1) vectors based on the (j+1) sets of n digitized samples, each vector having signal estimates of a transmitted signal for a respective time (p-t), where t=0 to j;
(c) storing the j vectors; and
(d) providing an estimate vector having signal estimates of the transmitted signal for time (p-j), based on the (j+1) vectors.
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Abstract
The present invention provides an apparatus and method for signal recovery from noisy observation in digital communication systems, utilizing a forward estimator and data smoother which improves the quality of the estimates of the transmitted signal. The present invention also provides an apparatus and method for the application of the forward estimator to the recovery of a digital data stream modulated with a CPM waveform, through the use of a receiver for GMSK demodulation. The digital data is first processed using the Forward Estimation process which calculates the probability that a symbol is in particular states. Bit decision is then applied, followed by scaling. The present invention further provides an apparatus and method for the application of the forward estimator and data smoother to the decoding of digital data which has been encoded with a Convolutional code. The digital data is first processed using the Forward Estimation procedure and then smoothed and scaled. Bit decision is then applied.
18 Citations
54 Claims
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1. A method of recovering transmitted signals in a digital communications system, comprising the steps of:
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(a) obtaining n samples of a received signal for a respective time p, p-1, p-2, . . . , p-j and digitizing the n samples to provide (j+1) sets of n digitized samples; (b) providing (j+1) vectors based on the (j+1) sets of n digitized samples, each vector having signal estimates of a transmitted signal for a respective time (p-t), where t=0 to j; (c) storing the j vectors; and (d) providing an estimate vector having signal estimates of the transmitted signal for time (p-j), based on the (j+1) vectors. - View Dependent Claims (2, 3, 4)
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5. A method of recovering transmitted continuous phase modulated signals in a digital communications system, comprising the steps of:
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(a) obtaining n samples of a received signal for a respective time p, p-1, p-2, . . . , p-j and digitizing the n samples to provide (j+1) sets of n digitized samples; (b) providing (j+1) vectors based on the (j+1) sets of n digitized samples, each vector having signal estimates of a transmitted continuous phase modulated signal for a respective time (p-t), where t=0 to j; (c) storing the j vectors; and (d) providing an estimate vector having signal estimates of the transmitted signal for time (p-j), based on the (j+1) vectors. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. A method of decoding transmitted Convolutionally encoded signals in a digital communication system, comprising the steps of:
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(a) obtaining n samples of a received signal for a respective time p, p-1, p-2, . . . , p-j and digitizing the n samples to provide (j+1) sets of n digitized samples; (b) providing (j+1) vectors based on the (j+1) sets of n digitized samples, each vector having signal estimates of a transmitted signal for a respective time (p-t), where t=0 to j; (c) storing the j vectors; and (d) providing an estimate vector having signal estimates of the transmitted signal for time (p-j), based on the (j+1) vectors. - View Dependent Claims (14, 15, 16, 17, 18)
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19. An apparatus for recovering transmitted signals in a digital communications system, comprising:
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a receiver for obtaining n samples of a received signal for a respective time p, p-1, p-2, . . . , p-j and digitizing the n samples to provide (j+1) sets of n digitized samples; a decoder for providing (j+1) vectors based on the (j+1) sets of n digitized samples, each vector having signal estimates of a transmitted signal for a respective time (p-t), where t=0 to j; a register for storing the j vectors; and the decoder also providing an estimate vector having signal estimates of the transmitted signal for time (p-j), based on the (j+1) vectors. - View Dependent Claims (20, 21, 22)
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23. An apparatus for recovering transmitted continuous phase modulated signals in a digital communications system, comprising:
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a receiver for obtaining n samples of a received signal for a respective time p, p-1, p-2, . . . , p-j and digitizing the n samples to provide (j+1) sets of n digitized samples; a decoder for providing (j+1) vectors based on the (j+1) sets of n digitized samples, each vector having signal estimates of a transmitted continuous phase modulated signal for a respective time (p-t), where t=0 to j; a register for storing the j vectors; and the decoder also providing an estimate vector having signal estimates of the transmitted signal for time (p-j), based on the (j+1) vectors. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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31. An apparatus for decoding transmitted Convolutionally encoded signals in a digital communication system, comprising:
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a receiver for obtaining n samples of a received signal for a respective time p, p-1, p-2, . . . , p-j and digitizing the n samples to provide (j+1) sets of n digitized samples; a decoder for providing (j+1) vectors based on the (j+1) sets of n digitized samples, each vector having signal estimates of a transmitted Convolutionally encoded signal for a respective time (p-t), where t=0 to j; a register for storing the j vectors; and the decoder also providing an estimate vector having signal estimates of the transmitted signal for time (p-j), based on the (j+1) vectors. - View Dependent Claims (32, 33, 34, 35, 36)
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37. Computer-executable process steps for recovering transmitted signals in a digital communications system, the process steps including:
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(a) obtaining n samples of a received signal for a respective time p, p-1, p-2, . . . , p-j and digitizing the n samples to provide (j+1) sets of n digitized samples; (b) providing (j+1) vectors based on the (j+1) sets of n digitized samples, each vector having signal estimates of a transmitted signal for a respective time (p-t), where t=0 to j; (c) storing the j vectors; and (d) providing an estimate vector having signal estimates of the transmitted signal for time (p-j), based on the (j+1) vectors. - View Dependent Claims (38, 39, 40)
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41. Computer-executable process steps for recovering transmitted continuous phase modulated signals in a digital communications system, including the steps of:
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(a) obtaining n samples of a received signal for a respective time p, p-1, p-2, . . . , p-j and digitizing the n samples to provide (j+1) sets of n digitized samples; (b) providing (j+1) vectors based on the (j+1) sets of n digitized samples, each vector having signal estimates of a transmitted continuous phase modulated signal for a respective time (p-t), where t=0 to j; (c) storing the j vectors; and (d) providing an estimate vector having signal estimates of the transmitted signal for time (p-j), based on the (j+1) vectors. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48)
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49. Computer-executable process steps of decoding transmitted Convolutionally encoded signals in a digital communication system, including the steps of:
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(a) obtaining n samples of a received signal for a respective time p, p-1, p-2, . . . , p-j and digitizing the n samples to provide (j+1) sets of n digitized samples; (b) providing (j+1) vectors based on the (j+1) sets of n digitized samples, each vector having signal estimates of a transmitted Convolutionally encoded signal for a respective time (p-t), where t=0 to j; (c) storing the j vectors; and (d) providing an estimate vector having signal estimates of the transmitted signal for time (p-j), based on the (j+1) vectors. - View Dependent Claims (50, 51, 52, 53, 54)
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Specification