Transmitter for encoded data bits
First Claim
1. A transmitter for generating Quadrature Amplitude Modulated signals from data bits, the transmitter comprising:
- first Quadrature Phase Shift Keying (QPSK) means for encoding a first pair of the data bits into one of four carrier signal phases, thereby producing a first QPSK signal;
second QPSK means for encoding a second pair of the data bits into one of four carrier signal phases, thereby producing a second QPSK signal;
a first power amplifier for amplifying the first QPSK signal to a first power level and supplying a first amplified signal at an output of the first power amplifier;
a second power amplifier for amplifying the second QPSK signal to a second power level and supplying a second amplified signal at an output of the second power amplifier; and
combining means for combining the first and second amplified signals to produce a signal in which four data bits are encoded.
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Accused Products
Abstract
Quadrature Amplitude Modulated signals are generated from data bits by using a first Quadrature Phase Shift Keying (QPSK) modulator for encoding a first pair of the data bits into one of four carrier signal phases, thereby producing a first QPSK signal. A second QPSK modulator encodes a second pair of the data bits into one of four carrier signal phases, thereby producing a second QPSK signal. The first QPSK signal is amplified to a first power level, and the second QPSK signal is amplified to a second power level. The first and second amplified signals are then combined to produce a signal in which four data bits are encoded. In another aspect of the invention, a new type of modulation, called Offset Quadrature Phase Shift Keying (OQPSK), is used in place of the first and second QPSK modulators, so that an Offset Quadrature Amplitude Modulation (OQAM) transmitter is formed. An OQPSK modulator encodes data bits by encoding a first sub-group of the data bits into a real part of a complex signal at an odd instant of a clock, and by encoding a second sub-group of the data bits into an imaginary part of the complex signal at an even instant of the clock. OQPSK modulation provides the benefit of having all signal transitions being constrained to trajectories around constant radius circles, thereby producing spectral efficiency.
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Citations
42 Claims
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1. A transmitter for generating Quadrature Amplitude Modulated signals from data bits, the transmitter comprising:
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first Quadrature Phase Shift Keying (QPSK) means for encoding a first pair of the data bits into one of four carrier signal phases, thereby producing a first QPSK signal; second QPSK means for encoding a second pair of the data bits into one of four carrier signal phases, thereby producing a second QPSK signal; a first power amplifier for amplifying the first QPSK signal to a first power level and supplying a first amplified signal at an output of the first power amplifier; a second power amplifier for amplifying the second QPSK signal to a second power level and supplying a second amplified signal at an output of the second power amplifier; and combining means for combining the first and second amplified signals to produce a signal in which four data bits are encoded. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for encoding groups of data bits into a complex signal for transmission, the apparatus comprising:
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means for encoding a first sub-group of the data bits into a real part of a complex signal at an odd instant of a clock; and means for encoding a second sub-group of the data bits into an imaginary part of the complex signal at an even instant of the clock. - View Dependent Claims (9, 10)
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11. An apparatus for encoding a group of data bits into a complex signal for transmission, the apparatus comprising:
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means for encoding a first pair of data bits into a first Offset Quadrature Phase Shift Keying (OQPSK) signal; means for encoding a second pair of data bits into a second OQPSK signal; a first power amplifier for amplifying the first OQPSK signal to a first power level; a second power amplifier for amplifying the second OQPSK signal to a second power level; and combining means for combining outputs of the first and second power amplifiers to produce a complex vector modulated signal in which four data bits are encoded. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for generating Quadrature Amplitude Modulated signals from data bits, the method comprising:
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utilizing Quadrature Phase Shift Keying (QPSK) to encode a first pair of the data bits into one of four carrier signal phases, thereby producing a first QPSK signal; utilizing QPSK to encode a second pair of the data bits into one of four carrier signal phases, thereby producing a second QPSK signal; generating a first amplified signal by amplifying the first QPSK signal to a first power level; generating a second amplified signal by amplifying the second QPSK signal to a second power level; and combining the first and second amplified signals to produce a signal in which four data bits are encoded. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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29. A method of encoding groups of data bits into a complex signal for transmission comprising the steps of:
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encoding a first sub-group of the data bits into a real part of a complex signal at an odd instant of a clock; and encoding a second sub-group of the data bits into an imaginary part of the complex signal at an even instant of the clock. - View Dependent Claims (30, 31)
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32. A method of encoding a group of data bits into a complex signal for transmission comprising the steps of:
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encoding a first pair of data bits into a first Offset Quadrature Phase Shift Keying (OQPSK) signal; encoding a second pair of data bits into a second OQPSK signal; amplifying the first OQPSK signal to a first power level using a first power amplifier; amplifying the second OQPSK signal to a second power level using a second power amplifier; and combining outputs of the first and second power amplifiers to produce a complex vector modulated signal in which four data bits are encoded. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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Specification