Method and apparatus for variable rate signal transmission in a spread spectrum communication system using coset coding
First Claim
1. A transmitter for modulating an information signal for transmission in a spread spectrum communication system comprising:
- means for demultiplexing said information signal into first and second subsignals;
first means for combining said first subsignal with a first coset code and for combining said second subsignal with a second coset code orthogonal to said first coset code so as to produce a first composite coset-encoded signal;
means for generating an orthogonal function signal; and
means for modulating said first composite coset-encoded signal with said orthogonal function signal in order to provide a first modulated signal.
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Abstract
An improved system and method for communicating information at variable data rates over in-phase (I) and quadrature phase (Q) communication channels in a CDMA spread spectrum communication system is disclosed herein. In an exemplary implementation an input information signal is transmitted over either an I or Q communication channel using a direct sequence spread spectrum communication signal. The information signal is initially divided into first and second subsignals, which are respectively provided to first and second coset-encoding networks. The first coset-encoding combines the first subsignal with a first coset code, while the second coset-encoding network combines the second subsignal with a second coset code orthogonal to the first coset code. In this way the first and second coset-encoding networks are operative to produce first and second coset-encoded signals, respectively. A composite coset-encoded signal formed from the first and second coset-encoded signals is then modulated by an orthogonal function signal to provide a first modulated signal. In-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ) signals of predetermined PN codes are used for spreading the first modulated signal for transmission to a receiver over either the I or Q communication channel, respectively. The receiver is operative to produce an estimate of the input information signal on the basis of the modulated carrier signal received over either the I or Q communication channel.
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Citations
30 Claims
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1. A transmitter for modulating an information signal for transmission in a spread spectrum communication system comprising:
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means for demultiplexing said information signal into first and second subsignals; first means for combining said first subsignal with a first coset code and for combining said second subsignal with a second coset code orthogonal to said first coset code so as to produce a first composite coset-encoded signal; means for generating an orthogonal function signal; and means for modulating said first composite coset-encoded signal with said orthogonal function signal in order to provide a first modulated signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 11)
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8. A transmitter for modulating a set of p information signals of equivalent data rate for simultaneous transmission in a spread spectrum communication system, comprising:
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means for combining each of said information signals with one of a set of p coset codes to produce a set of p coset-encoded signals; means for combining said p coset-encoded signals and for generating a composite coset-encoded signal; means for generating an orthogonal function signal; and means for modulating said composite coset-encoded signal with said orthogonal function signal in order to provide a first modulated signal. - View Dependent Claims (9, 10)
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12. A spread spectrum communication system for modulating an information signal to be transmitted on in-phase (I) and quadrature phase (Q) using a carrier signal and a replica of said carrier signal in phase quadrature therewith, said system including a transmitter comprising:
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means for demultiplexing said information signal into first and second sets of subsignals; means for combining said first set of subsignals with a first set of orthogonal coset codes to produce a first composite coset-encoded signal, and for combining said second set of subsignals with a second set of orthogonal coset codes so as to produce a second composite coset-encoded signal; means for generating an orthogonal function signal; means for generating in-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ) signals of predetermined PN codes; and means for combining said PNI signal with said first composite coset-encoded signal and said orthogonal function signal to provide an I modulation signal, and for combining said PNQ signal with said second composite coset-encoded signal and said orthogonal function signal to provide a Q modulation signal. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for modulating an information signal for transmission in a spread spectrum communication system, comprising the steps of:
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demultiplexing said information signal into first and second subsignals; combining said first subsignal with a first coset code and combining said second subsignal with a second coset code orthogonal to said first coset code so as to produce a first composite coset-encoded signal; generating an orthogonal function signal; and modulating said first composite coset-encoded signal with said orthogonal function signal in order to provide a first modulated signal. - View Dependent Claims (23, 24, 25)
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26. A method for modulating a set of p information signals of equivalent data rate for simultaneous transmission in a spread spectrum communication system, comprising the steps of:
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combining each of said information signals with one of a set of p coset codes to produce a set of p coset-encoded signals; combining said p coset-encoded signals and so as to generate a composite coset-encoded signal; modulating said composite coset-encoded signal with an orthogonal function signal in order to provide a first modulated signal.
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27. In a code division multiple access (CDMA) communication system, a method for providing in-phase (I) and quadrature phase (Q) spread spectrum communication channels over which is transmitted an information signal, said method comprising the steps of:
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demultiplexing said information signal into first and second sets of subsignals; combining said first set of subsignals with a first set of orthogonal coset codes to produce a first composite coset-encoded signal, and combining said second set of subsignals with a second set of orthogonal coset codes so as to produce a second composite coset-encoded signal; generating in-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ) signals of predetermined PN codes; and combining said PNI signal with said first composite coset-encoded signal and an orthogonal function signal to provide an I modulation signal, and combining said PNQ signal with said second composite coset-encoded signal and said orthogonal function signal to provide a Q modulation signal. - View Dependent Claims (28, 29, 30)
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Specification