Use of diversity transmission to relax adjacent channel requirements in mobile telephone systems
First Claim
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1. A diversity transmission system comprising:
- a first modulator for modulating a first set of information signals on to a first radio carrier frequency;
a second modulator for modulating at least one of a second set of information signals on to a second radio carrier frequency; and
a radio frequency combining network for combining outputs of said first and second modulators with other signals having different carrier frequencies and coupling said combined signal to a common power amplifier and antenna for transmission, wherein said at least one of said second set of information signals serves as a diversity transmission and is transmitted at a power level lower than a same signal transmitted on said second carrier via a second antenna.
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Abstract
The present invention includes a system and method for reducing adjacent channel interference, particularly in CDMA radiotelephone systems. Diversity transmissions are provided for weaker signals to be transmitted by coupling delayed or advanced versions of these weaker signals to an antenna which is also transmitting signals on an adjacent frequency.
75 Citations
45 Claims
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1. A diversity transmission system comprising:
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a first modulator for modulating a first set of information signals on to a first radio carrier frequency; a second modulator for modulating at least one of a second set of information signals on to a second radio carrier frequency; and a radio frequency combining network for combining outputs of said first and second modulators with other signals having different carrier frequencies and coupling said combined signal to a common power amplifier and antenna for transmission, wherein said at least one of said second set of information signals serves as a diversity transmission and is transmitted at a power level lower than a same signal transmitted on said second carrier via a second antenna. - View Dependent Claims (2)
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3. A diversity transmission system comprising:
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a first modulator for modulating a first set of information signals on to a first radio carrier frequency; a second modulator for modulating at least one of a second set of information signals on to a second radio carrier frequency; and a radio frequency combining network for combining outputs of said first and second modulators and coupling the combined signal to a common power amplifier and antenna for transmission, wherein said at least one of said second set of information signals serves as a diversity transmission and is transmitted at a power level lower than a same signal transmitted on said second carrier frequency via a second antenna. - View Dependent Claims (4, 5, 6, 7, 8)
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9. A diversity transmission system comprising:
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a first modulator for modulating a first set of information signals on to a first radio carrier frequency; a second modulator for modulating at least one of a second set of information signals on to a second radio carrier frequency; a first transmit power amplifier for said modulated signal at said first carrier frequency; a second transmit power amplifier for said modulated signal at said second carrier frequency; and a radio frequency combining network for combining the outputs of said first and second transmit power amplifiers and coupling the combined signal to a first antenna for transmission, wherein said at least one of said second set of information signals serves as a diversity transmission and is transmitted at a power level lower than a same signal transmitted on said second carrier frequency via a second antenna. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A diversity transmission system comprising:
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a first modulator for modulating a first set of information signals on to a first carrier frequency; a second modulator for modulating at least one of a second set of information signals on to a second carrier frequency; a first transmit power amplifier for said modulated signal at said first carrier frequency; a second transmit power amplifier for said modulated signal at said second carrier frequency; an antenna multiplexing filter that combines an output of said first transmit power amplifier with at least one other signal having at least a third carrier frequency intended for transmission from the same antenna; and a radio frequency combining network for combining the outputs of said antenna multiplexing filter and said second transmit power amplifier and coupling the combined signal to a first antenna for transmission, wherein said at least one of said second set of information signals serves as a diversity transmission and is transmitted at a power level lower than a same signal transmitted on said second carrier frequency via a second antenna. - View Dependent Claims (27, 28)
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29. A diversity transmission system comprising:
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a first modulator for modulating a first set of information signals on to a first carrier frequency; a second modulator for modulating at least one of a second set of information signals on to a second radio carrier frequency; a first transmit power amplifier for said modulated signal at said first carrier frequency; a second transmit power amplifier for said modulated signal at said second carrier frequency; a first antenna multiplexing filter that combines an output of said first transmit power amplifier with at least one other signal having at a least a third carrier frequency intended for transmission from the first same; a second antenna multiplexing filter that combines an output of said second transmit power amplifier with at least one other signal having at least a fourth carrier frequency intended for transmission from the same antenna; and a radio frequency combining network for combining the outputs of said first and second antenna multiplexing filters and coupling the combined signal to a first antenna for transmission, wherein said at least one of said second set of information signals serves as a diversity transmission and is transmitted at a power level lower than a same signal transmitted on said second carrier frequency via a second antenna. - View Dependent Claims (30, 31, 32, 33, 34)
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35. A method for diversity transmission of signals in a radiotelephone system comprising the steps of:
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modulating a first set of information signals onto a first set of frequency channels to produce a first set of transmit signals for transmission from a first antenna; modulating a second set of information signals onto a second set of frequency channels to produce a second set of transmit signals; modulating selected ones of the first set of information signals onto the first set of frequency channels to produce diversity signals; combining the second set of transmit signals with the diversity signals for transmission from a second antenna; wherein the first set of frequency channels comprises frequency bands which are adjacent in frequency to and alternate in frequency with frequency bands of the second set of frequency channels. - View Dependent Claims (36, 37)
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38. A diversity transmission system comprising:
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first modulating means for modulating a first set of information signals onto a first set of frequency channels to produce a first set of transmit signals for transmission from a first antenna; second modulating means for modulating a second set of information signals onto a second set of frequency channels to produce a second set of transmit signals; third modulating means for modulating selected ones of the first set of information signals onto the first set of frequency channels to produce diversity signals; a combiner for combining the second set of transmit signals with the diversity signals for transmission from a second antenna; wherein the first set of frequency channels is adjacent in frequency to and alternates in frequency with the second set of frequency channels. - View Dependent Claims (39, 40)
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41. A radio transmission system for multiple signals comprising:
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first transmit means for modulating a first set of information signals onto even-numbered radio channels and amplifying said first set of information signals to produce a first set of transmit signals; second transmit means for modulating a second set of information signals onto odd-numbered radio channels and amplifying said second set of information signals to produce a second set of transmit signals; third transmit means for modulating selected ones of said first set of information signals onto respectively assigned even-numbered radio channels and amplifying said selected signals to produce a diversity transmit signal; first transmit multiplexer means for multiplexing said first set of transmit signals to form a first composite signal and feeding said first composite signal to a first antenna means; second transmit multiplexer means for multiplexing said second set of transmit signals to form a second composite signal, and coupling means for coupling said second composite signal and said diversity transmit signal to a second antenna means. - View Dependent Claims (42, 43, 44, 45)
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Specification