Method and apparatus for bifurcating signal transmission over in-phase and quadrature phase spread spectrum communication channels
First Claim
1. A modulation system for modulating first and second information signals for transmission in a spread spectrum communication system to first and second system user, said communication system being operative at a predefined nominal data rate, said modulation system comprising:
- a PN signal generator for generating in-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ) signals of predetermined PN codes;
means for generating a first orthogonal function signal of a predefined length based on said nominal data rate;
a modulation network for combining said PNI signal with said first information signal and said first orthogonal function signal to provide an I modulation signal, and for combining said PNQ signal with said second information signal and said first orthogonal function signal to provide a Q modulation signal; and
a transmit modulator for modulating in-phase (I) and quadrature phase (Q) carrier signals of a predefined phase relationship with said I and Q modulation signals for transmission to said first and second system user, respectively.
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Abstract
An improved system and method for communicating information over in-phase (I) and quadrature phase (Q) communication channels in a spread spectrum communication system is disclosed herein. In an exemplary implementation, first and second information signals are respectively transmitted over the I and Q communication channels using direct sequence spread spectrum communication signals. In-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ) signals of predetermined PN codes are used for spreading the first and second information signals, respectively. In particular, the PNI and PNQ signals are respectively combined with the first and second information signals and an orthogonal function signal to provide I-channel and Q-channel modulation signals. The I-channel and Q-channel modulation signals are used for modulating in-phase (I) and quadrature phase (Q) carrier signals for transmission to a receiver via the I and Q communication channels, respectively. In a preferred implementation the receiver is operative to produce an estimate of at least the first information signal on the basis of the I-channel and Q-channel modulated carrier signals received over the I and Q communication channels. The received I-channel and Q-channel modulated carrier signals are demodulated and despread, with the resultant sequences being correlated into in-phase (I) and quadrature phase (Q) projection signals. A phase rotator operates to provide an estimate of at least the first information signal based on the I and Q projection signals and a received pilot signal.
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Citations
38 Claims
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1. A modulation system for modulating first and second information signals for transmission in a spread spectrum communication system to first and second system user, said communication system being operative at a predefined nominal data rate, said modulation system comprising:
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a PN signal generator for generating in-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ) signals of predetermined PN codes; means for generating a first orthogonal function signal of a predefined length based on said nominal data rate; a modulation network for combining said PNI signal with said first information signal and said first orthogonal function signal to provide an I modulation signal, and for combining said PNQ signal with said second information signal and said first orthogonal function signal to provide a Q modulation signal; and a transmit modulator for modulating in-phase (I) and quadrature phase (Q) carrier signals of a predefined phase relationship with said I and Q modulation signals for transmission to said first and second system user, respectively. - View Dependent Claims (2, 3)
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4. A modulation system for modulating an information signal of an input data rate, said information signal being transmitted on in-phase (I) and quadrature phase (Q) channels of a spread spectrum communication system using a carrier signal and a replica of said carrier signal in phase quadrature therewith, said I and Q channels being disposed to operate at a predetermined nominal data rate independent of said input data rate, comprising:
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a divider circuit for dividing said information signal into first and second portions, and for encoding said first and second portions into first and second encoded signals at said predetermined nominal rate for transmission to one or more intended recipient users over said I and Q channels; means for generating an orthogonal function signal of a predefined length based upon said nominal data rate; a PN signal generator for generating in-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ) signals of predetermined PN codes; a modulation network for combining said PNI signal with said first portion of said information signal and said orthogonal function signal to provide an I modulation signal, and for combining said PNQ signal with said second portion of said information signal and said orthogonal function signal to provide a Q modulation signal; and a transmit modulator for modulating said carrier signal and said replica of said carrier signal with said I and Q modulation signals, respectively. - View Dependent Claims (5, 6)
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7. A code division multiple access (CDMA) communication system for providing in-phase (I) and quadrature phase (Q) spread spectrum communication channels over which are respectively transmitted a first information signal and it second information signal different from said first information signal, comprising:
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a PN generator for generating in-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ)signals of predetermined PN codes; means for generating an orthogonal function signal; a modulation network for combining said PNI signal with said first information signal and said orthogonal function signal to provide an I modulation signal, and for combining said PNQ signal with said second information signal and said orthogonal function signal to provide a Q modulation signal; a transmit modulator for modulating in-phase (I) and quadrature phase (Q) carrier signals of a predefined phase relationship with said I and Q modulation signals, and for transmitting said I and Q carrier signals over said I and Q communication channels, respectively; and a receiver for producing an estimate of at least said first information signal in accordance with said I and Q modulated carrier signals received over said I and Q communication channels. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A method for transmitting first and second information signals respectively to first and second users in a spread spectrum communication system comprising the steps of:
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generating in-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ) signals of predetermined PN codes; generating a first PN code sequence associated with said first user, and a second PN code sequence associated with said second user; generating an orthogonal function signal of predefined length; combining said PNI signal, said first PN code sequence and said orthogonal function signal with said first information signal to provide an I modulation signal, and combining said PNQ signal, said second PN code sequence and said orthogonal function signal with said second information signal to provide a Q modulation signal; and modulating in-phase (I) and quadrature phase (Q) carrier signals of a predefined phase relationship with said I and Q modulation signals for transmission to said first and second users, respectively. - View Dependent Claims (16, 17, 18)
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19. A method for modulating an information signal at an input data rate to be transmitted on in-phase (I) and quadrature phase (Q) channels of a spread spectrum communication system using a carrier signal and a replica of said carrier signal in phase quadrature therewith, said I and Q channels being disposed to operate at a predetermined nominal data rate independent of said input data rate, comprising:
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dividing said information signal into first and second portions for transmission to one or more intended recipient users over said I and Q channels; generating an orthogonal function signal of a predefined length independent of said input data rate; generating in-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ) signals of predetermined PN codes; combining said PNI signal with said first portion of said information signal and said orthogonal function signal to provide an I modulation signal, and combining said PNQ signal with said second portion of said information signal and said orthogonal function signal to provide a Q modulation signal; and modulating said carrier signal and said replica of said carrier signal with said I and Q modulation signals, respectively. - View Dependent Claims (20, 21)
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22. 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 are transmitted a first information signal and a second information signal different from said first information signal, said method comprising the steps of:
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generating in-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ) signals of predetermined PN codes; generating an orthogonal function signal; combining said PNI signal with said first information signal and said orthogonal function signal to provide an I modulation signal, and combining said PNQ signal with said second information signal and said orthogonal function signal to provide a Q modulation signal; modulating in-phase (I) and quadrature phase (Q) carrier signals of a predefined phase relationship with said I and Q modulation signals; transmitting said I and Q carrier signals over said I and Q communication channels, respectively; and producing an estimate of at least said first information signal in accordance with said I and Q modulated carrier signals received over said I and Q communication channels. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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29. A modulation system for modulating first and second information signals for transmission in a spread spectrum communication system to first and second system users, said modulation system comprising:
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a PN signal generator for generating in-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ)signals of predetermined PN codes; a code sequence generator for generating a first PN code sequence associated with said first system user, and for generating a second PN code sequence associated with said second system user; an orthogonal function generator for generating a first orthogonal function signal of a predefined length; a modulation network for combining said PNI signal, said first PN code sequence and said orthogonal function signal with said first information signal to provide an I modulation signal, and combining said PNQ signal, said second PN code sequence and said orthogonal function signal with said second information signal to provide a Q modulation signal; and a transmit modulator for modulating in-phase (I) and quadrature phase (Q) carrier signals of a predefined phase relationship with said I and Q modulation signals for transmission to said first and second system users, respectively.
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30. A method for modulating first and second information signals for transmission in a spread spectrum communication system to first and second system users, said method comprising the steps of:
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generating in-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ) signals of predetermined PN codes; generating a first PN code sequence associated with said first system user, and generating a second PN code sequence associated with said second system user; generating a first orthogonal function signal of a predefined length; combining said PNI signal, said first PN code sequence and said orthogonal function signal with said first information signal to provide an I modulation signal, and combining said PNQ signal, said second PN code sequence and said orthogonal function signal with said second information signal to provide a Q modulation signal; and modulating in-phase (I) and quadrature phase (Q) carrier signals of a predefined phase relationship with said I and Q modulation signals for transmission to said first and second system users, respectively.
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31. A dual-mode modulation system for, during operation in a first mode, modulating first and second information signals for transmission in a spread spectrum communication system to first and second system users and for modulating, during operation in a second mode, a third information signal of an input data rate, said third information signal being transmitted on in-phase (I) and quadrature phase (Q) channels of the spread spectrum communication system using a carrier signal and a replica of said carrier signal in phase quadrature therewith, said dual-mode modulation system comprising:
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a divider circuit for dividing, during operation in said second mode, said third information signal into first and second portions for transmission to one or more intended recipient users over said I and Q channels; a PN signal generator for generating in-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ) signals of predetermined PN codes; an orthogonal function signal generator for generating a first orthogonal function signal of a predefined length based on a nominal data rate of said communication system; a modulation network for combining said PNI signal with said first information signal and said first orthogonal function signal to provide an I modulation signal during operation in said first mode and for combining said PNI signal with said third information signal and said first orthogonal function signal to provide said I modulation signal during operation in said second mode, and for combining said PNQ signal with said second information signal and said first orthogonal function signal to provide a Q modulation signal during operation in said first mode and for combining said PNQ signal with said third information signal and said first orthogonal function signal to provide said Q modulation signal during operation in said second mode; and a transmit modulator for modulating in-phase (I) and quadrature phase (Q) carrier signals of a predefined phase relationship with said I and Q modulation signals for transmission over said I and Q communication channels, respectively.
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32. A method for modulating first and second information signals for transmission in a spread spectrum communication system to first and second system users during operation of said system in a first mode, and for modulating a third information signal of an input data rate, said third information signal being transmitted on in-phase (I) and quadrature phase (Q) channels of the spread spectrum communication system during operation in a second mode using a carrier signal and a replica of said carrier signal in phase quadrature therewith, said method comprising the steps of:
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dividing, during operation in said second mode, said third information signal into first and second portions for transmission to one or more intended recipient users over said I and Q channels; generating in-phase pseudorandom noise (PNI) and quadrature phase pseudorandom noise (PNQ) signals of predetermined PN codes; generating a first orthogonal function signal of a predefined length based on a nominal data rate of said communication system; combining said PNI signal with said first information signal and said first orthogonal function signal to provide an I modulation signal during operation in said first mode and for combining said PNI signal with said third information signal and said first orthogonal function signal to provide said I modulation signal during operation in said second mode, and for combining said PNQ signal with said second information signal and said first orthogonal function signal to provide a Q modulation signal during operation in said first mode and for combining said PNQ signal with said third information signal and said first orthogonal function signal to provide said Q modulation signal during operation in said second mode; and modulating in-phase (I) and quadrature phase (Q) carrier signals of a predefined phase relationship with said I and Q modulation signals for transmission over said I and Q communication channels, respectively.
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- 33. In a code division multiple access (CDMA) communication system for providing in-phase (I) and quadrature phase (Q) spread spectrum communication channels over which are respectively transmitted different first and second information signals using I and Q modulated carrier signals, a receiver for producing an estimate of at least said first information signal in accordance with said I and Q modulated carrier signals received over said I and Q communication channels.
- 36. In a code division multiple access (CDMA) communication system for providing in-phase (I) and quadrature phase (Q) spread spectrum communication channels over which are respectively transmitted different first and second information signals using I and Q modulated carrier signals, a method of receiving information transmitted over said I and Q communication channels comprising the step of producing an estimate of at least said first information signal in accordance with said I and Q modulated carrier signals received over said I and Q communication channels.
Specification