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US 7,095,290 B2Granted
Method and system for generating higher order modulations with QPSK modulator
AssigneeNokia Corporation
InventorsHannu Häkkinen, Pekka Kyösti
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Abstract
Method and system for generating higher order modulations with QPSK modulators. A complex sequence of binary digits is input to QPSK modulators. The binary digits are mapped to constellation points and multiplied with weighting coefficient. Constellation points of higher order modulation are mapped to inputs of the QPSK modulator, and, after modulation QPSK symbols are summed to compose symbols of higher order modulation.
Claims15
Method for generating higher order modulations with QPSK modulators wherein
- a complex-valued input chip sequence is split into real and imaginary parts by a splitter and input to QPSK modulators in which the sequence is mapped to constellation points, multiplied with weighting coefficients in first multipliers, outputs of the multipliers are pulse shaped and supplied to second multipliers for multiplication by cos (ωt) and −sin(ωt), respectively, and the outputs of these multipliers are summed by an adder, thereby generating a resulting signal of the QPSK modulators,
- the resulting signal is spread by multiplying it with spreading code,
- constellation points of higher order modulation are mapped to inputs of the QPSK modulator, and,
- after modulation and spreading, QPSK symbols are summed to compose symbols of higher order modulation.
1 more element
System for generating higher order modulations with QPSK modulators comprising
- means for splitting a complex-valued chip sequence into real and imaginary parts,
- means for inputting the sequence to QPSK modulators in which the sequences is mapped to constellation points, multiplied with weighting coefficients in first means for multiplying, outputs of the first means for multiplying are pulse shaped and supplied to second means for multiplying for multiplication by cos (ωt) and −sin(ωt), respectively, and the outputs of the second means for multiplying are summed by means for adding, thereby generating a resulting signal of the QPSK modulators,
- means for spreading the resulting signal,
- means for mapping constellation points of higher order modulation to inputs of the QPSK modulator, and,
- means for summing, after modulation and spreading, QPSK symbols to compose symbols of higher order modulation.
2 more elements
Dependencies are inferred from the claim text.