Method and system for blind detection of modulation type
First Claim
1. A method of demodulating a symbol in a receiver of a communication system without knowledge of the modulation constellation employed in a transmitter to modulate the symbol before transmission, the method comprising:
- (a) demodulating the symbol according to an assumed modulation constellation;
(b) interpreting the modulation symbol as a symbol of one of a family of hierarchical modulation constellations;
(c) decoding the demodulated symbol using a forward error correction (FEC) technique; and
(d) checking the decoded symbol for correctness, wherein during the interpretation step Mmax−
Ks of the symbol bits are applied to the FEC decoder where Mmax denotes the number of symbol bits of highest order modulation constellation, Ks is a value which varies for each assumed modulation constellation according to Ks=Mmax−
Ms, where Ms is the number of symbol bits of the respective assumed modulation constellation.
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Abstract
The invention relates to a method and a receiver for demodulating a modulation symbol in a communication system without knowledge of the modulation constellation employed in a transmitter to modulate this symbol before transmission. According to the method, the invention comprises the steps of interpreting the modulation symbol as a symbol of one of a family of hierarchical modulation constellations, decoding the demodulated symbol using a forward error correction (FEC) technique and demodulating the symbol according to the assumed modulation constellation. Finally, the demodulated symbol is checked for correctness. The receiver comprises of a corresponding interpretation unit, a demodulator and an FEC decoder as well as means for checking the correctness of the demodulated symbol.
18 Citations
15 Claims
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1. A method of demodulating a symbol in a receiver of a communication system without knowledge of the modulation constellation employed in a transmitter to modulate the symbol before transmission, the method comprising:
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(a) demodulating the symbol according to an assumed modulation constellation; (b) interpreting the modulation symbol as a symbol of one of a family of hierarchical modulation constellations; (c) decoding the demodulated symbol using a forward error correction (FEC) technique; and (d) checking the decoded symbol for correctness, wherein during the interpretation step Mmax−
Ks of the symbol bits are applied to the FEC decoder where Mmax denotes the number of symbol bits of highest order modulation constellation, Ks is a value which varies for each assumed modulation constellation according to Ks=Mmax−
Ms, where Ms is the number of symbol bits of the respective assumed modulation constellation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A receiver in a communication system that demodulates a modulation symbol without knowledge of the modulation constellation employed in a transmitter to modulate the symbol prior to transmission, the receiver comprising:
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a demodulator that demodulates the symbol according to an assumed modulation constellation; an interpretation unit that interprets the modulation symbol as a symbol of one of a family of hierarchical modulation constellations; a forward error correction (FEC) decoder that decodes Mmax—
Ks bits of the demodulated symbol, where Mmax denotes the number of symbol bits of highest order modulation constellation, Ks is a value which varies for each assumed modulation constellation according to Ks=Mmax−
Ms, where Ms is the number of symbol bits of the respective assumed modulation constellation; andan error checker that checks the demodulated symbol for correctness. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification