System and method for generating signal waveforms in a CDMA cellular telephone system
First Claim
1. An apparatus for transmitting a plurality of data signals in a spread spectrum communication system, comprising:
- a plurality of signal generator means for providing a plurality of function signals, each function signal being generated according to a respective function of a plurality of orthogonal functions, wherein the plurality of signal generator means comprises;
an outer signal generator for generating an outer function signal;
multiple inner signal generators for generating a plurality of inner function signals each inner function signal being generated according to a respective function of said plurality of orthogonal functions;
a plurality of spreading means, each spreading means connected to a respective signal generator means and receiving a respective data signal of the plurality of data signals for producing a respective spread spectrum data signal in response to the respective data signal and a respective function signal, wherein each spreading means includes two exclusive-OR gates;
a first exclusive-OR gate having two inputs and one output, a first input connected to a respective inner signal generator and a second input receiving a respective data signal of the plurality of data signals; and
a second exclusive-OR gate having two inputs and an output, a first input connected to the outer signal generator, a second input connected to the output of the first exclusive-OR gate, and the output connected to a combining means;
a pilot signal generator means for generating a pilot signal according to a function which is orthogonal to each function of the plurality of orthogonal functions;
said combining means being connected to the plurality of spreading means, wherein said combining means combines a plurality of spread spectrum data signals into a combined spread spectrum data signal; and
a transmit means connected to the combining means for amplifying and transmitting the combined spread spectrum data signal.
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Abstract
A system and method for communicating information signals using spread spectrum communication techniques. PN sequences are constructed that provide orthogonality between the users so that mutual interference will be reduced, allowing higher capacity and better link performance. With orthogonal PN codes, the cross-correlation is zero over a predetermined time interval, resulting in no interference between the orthogonal codes, provided only that the code time frames are time aligned with each other. In an exemplary embodiment, signals are communicated between a cell-site and mobile units using direct sequence spread spectrum communication signals. In the cell-to-mobile link, pilot, sync, paging and voice channels are defined. Information communicated on the cell-to-mobile link channels are, in general, encoded, interleaved, bi-phase shift key (BPSK) modulated with orthogonal covering of each BPSK symbol along with quadrature phase shift key (QPSK) spreading of the covered symbols. In the mobile-to-cell link, access and voice channels are defined. Information communicated on the mobile-to-cell link channels are, in general, encoded, interleaved, orthogonal signaling along with QPSK spreading.
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Citations
27 Claims
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1. An apparatus for transmitting a plurality of data signals in a spread spectrum communication system, comprising:
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a plurality of signal generator means for providing a plurality of function signals, each function signal being generated according to a respective function of a plurality of orthogonal functions, wherein the plurality of signal generator means comprises; an outer signal generator for generating an outer function signal; multiple inner signal generators for generating a plurality of inner function signals each inner function signal being generated according to a respective function of said plurality of orthogonal functions; a plurality of spreading means, each spreading means connected to a respective signal generator means and receiving a respective data signal of the plurality of data signals for producing a respective spread spectrum data signal in response to the respective data signal and a respective function signal, wherein each spreading means includes two exclusive-OR gates; a first exclusive-OR gate having two inputs and one output, a first input connected to a respective inner signal generator and a second input receiving a respective data signal of the plurality of data signals; and a second exclusive-OR gate having two inputs and an output, a first input connected to the outer signal generator, a second input connected to the output of the first exclusive-OR gate, and the output connected to a combining means; a pilot signal generator means for generating a pilot signal according to a function which is orthogonal to each function of the plurality of orthogonal functions; said combining means being connected to the plurality of spreading means, wherein said combining means combines a plurality of spread spectrum data signals into a combined spread spectrum data signal; and a transmit means connected to the combining means for amplifying and transmitting the combined spread spectrum data signal.
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2. An apparatus for transmitting a plurality of data signals in a spread spectrum communication system, comprising:
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a plurality of signal generator means for providing a plurality of function signals, each function signal being generated according to a respective function of a plurality of orthogonal functions, wherein the plurality of signal generator means comprises; first and second outer signal generators for generating first and second outer function signals representing, respectively, first and second outer functions, the first outer function being substantially orthogonal to the second outer function; multiple inner signal generators for generating a plurality of inner function signals, each inner function signal being generated according to a respective function of said plurality of orthogonal functions; and a plurality of spreading means, each spreading means connected to a respective signal generator means and receiving a respective data signal of the plurality of data signals for producing a respective spread spectrum data signal in response to the respective data signal and a respective function signal;
wherein each spreading means includes three exclusive-OR gates;a first exclusive-OR gate having two inputs and one output, a first input connected to a respective inner signal generator and the second input receiving a respective data signal of the plurality of data signals; a second exclusive-OR gate having two inputs and an output, a first input connected to the first outer signal generator, a second input connected to the output of the first exclusive-OR gate, and the output connected to a combining means; and a third exclusive-OR gate having two inputs and an output, the first input connected to the second outer signal generator, the second input connected to the output of the first exclusive-OR gate, and the output connected to the combining means; said combining means being connected to the plurality of spreading means, wherein said combining means combines a plurality of spread spectrum data signals into a combined spread spectrum data signal; and a transmit means connected to the combining means for amplifying and transmitting the combined spread spectrum data signal. - View Dependent Claims (3, 4)
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5. An apparatus for spread spectrum transmission of a plurality of data signals, comprising:
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a plurality of signal generator means for providing a plurality of function signals, each function signal being provided according to a respective function of a plurality of orthogonal functions; a plurality of spreading means, each spreading means connected to a respective signal generator means and connected to receive a respective data signal of the plurality of data signals for spread spectrum generation of a respective spread spectrum data signal; means connected to the plurality of spreading means for combining a plurality of spread spectrum data signals to generate a combined spread spectrum data signal including the plurality of spread spectrum data signals; transmit means for amplifying and transmitting the combined spread spectrum data signal; and outer coding means for generating an outer code signal, and wherein each spreading means of the plurality of spreading means is further connected to the outer coding means for combining the outer code signal with a respective data signal and a respective function signal to produce a respective outer-coded spread spectrum data signal, and the means for combining is for generating the combined spread spectrum data signal including a plurality of outer coded spread spectrum data signals. - View Dependent Claims (6, 7, 8)
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9. A method for transmitting a plurality of data signals in a spread spectrum communication system, comprising the steps of:
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generating a plurality of function signals, each function signal being generated according to a respective function of a plurality of orthogonal functions; producing a plurality of spread spectrum data signals, each spread spectrum data signal of the plurality of spread spectrum data signals being produced by exclusive-OR combination of a respective function signal and a respective data signal of the plurality of data signals; combining the plurality of spread spectrum data signals into a combined spread spectrum data signal; amplifying and transmitting the combined spread spectrum data signal; generating an outer function signal; and wherein the combining step includes; producing a plurality of first spread spectrum signals, each first spread spectrum signal being produced by exclusive-OR combination of a respective function signal of the plurality of function signals with a respective data signal of the plurality of data signals; and producing a plurality of second spread spectrum signals, each second spread spectrum signal produced by exclusive-OR combination of a first spread spectrum signal with the outer function signal. - View Dependent Claims (10, 11)
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12. A method for spread spectrum transmission of a plurality of data signals, comprising the steps of:
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generating a plurality of function signals, each function signal being generated according to a respective function of a plurality of orthogonal functions; generating a plurality of spread spectrum data signals, each spread spectrum data signal produced by combining a respective data signal of the plurality of data signals with a respective function signal of the plurality of orthogonal function signals; producing a combined spread spectrum data signal by summation of the plurality of spread spectrum data signals; amplifying and transmitting the combined spread spectrum data signal; and generating an outer code signal; the step of generating the plurality of spread spectrum signals including combining the outer code signal with a respective data signal of the plurality of data signals and a respective function signal of the plurality of function signals to produce a respective outer coded spread spectrum data signal; and the step of producing a combined spread spectrum data signal including summation of a plurality of outer coded spread spectrum data signals. - View Dependent Claims (13)
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14. A communication modulation system, comprising:
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pilot signal generator means for generating a pilot signal according to a first orthogonal function selected from a set of orthogonal functions; communication signal generator means for receiving an input data signal, generating an orthogonal function signal according to a second orthogonal function selected from said set of orthogonal functions, wherein said second orthogonal function is different from said first orthogonal function, combining said orthogonal function signal with said input data signal and providing a resultant spread spectrum data signal; and outer coding means for receiving said pilot signal and said spread spectrum data signal, generating a pseudorandom noise (PN) signal of a predetermined PN code, combining said PN signal with said pilot signal and said spread spectrum data signal to produce corresponding PN-spread pilot and spread spectrum data signals. - View Dependent Claims (15, 16, 17)
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18. In a direct sequence spread spectrum modulator in which a plurality of channel signals are to be transmitted, a modulation method comprising the steps of:
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generating a plurality of orthogonal function signals each being generated according to a respective function of a set of orthogonal functions; receiving a plurality of input information signals; producing a plurality of spread channel information signals by modulo-2 addition of each of said information signals with a different one of said orthogonal function signals; combining the plurality of spread channel information signals into a modulated transmission signal comprising the steps of; generating a predetermined pseudorandom noise spreading code; modulating each of the plurality of spread channel information signals by the pseudorandom noise spreading code; and
, thencombining a plurality of modulated spread channel information signals into said modulated transmission signal; and providing a selected one of said orthogonal function signals as a pilot channel signal for spreading according to the predetermined pseudorandom noise spreading coding; wherein the step of modulating each of the plurality of spread channel information signals includes; receiving an input information signal; combining said information signal with a respective one of said orthogonal function signals; and providing an orthogonalized information signal as a corresponding spread channel information signal for spreading according to said predetermined pseudorandom noise spreading code.
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19. In a communication system in which a plurality of remote user stations communicate, via a radio link with a base station, with other user stations, said base station having a base station transceiver for communicating user station information signals to intended recipient remote user stations and for receiving remote user station communicated information signals for transfer to intended recipient user stations, said base station transceiver comprising:
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base station transmission means for receiving at least one user station information signal, spreading each received user station information signal according to a respective predetermined orthogonal function, and transmitting said spread user station information signals as a base station communication signal; and base station reception means for receiving and extracting from each remote user station transmitted remote user station communication signal a corresponding remote user station information signal for transfer to intended recipient user stations;
whereineach remote user station including a remote user station transceiver for communicating remote user station information signals to said base station for transfer to an intended recipient user station and for receiving and extracting from said base station communication signal respective user station information signals intended for said recipient remote user station, said remote user station transceiver comprising; remote user station transmission means for receiving a remote user station information signal, converting said remote user station information signal into respective groups of orthogonal function signals, modulating and transmitting said orthogonal function signals as a remote user station communication signal; and remote user station reception means for receiving and extracting from said base station communication signal said user station information signal intended for said remote user station. - View Dependent Claims (20, 21, 22)
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23. An apparatus for transmitting a plurality of data signals in a spread spectrum communication system, comprising:
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a plurality of signal generators that provide a plurality of function signals, each function signal being generated according to a respective function of a plurality of orthogonal functions, wherein the plurality of signal generators comprise an outer signal generator for generating an outer function signal; multiple inner signal generators for generating a plurality of inner function signals, each inner function signal being generated according to a respective function of said plurality of orthogonal functions; a plurality of spreaders, each spreader connected to a respective signal generator and receiving a respective data signal of the plurality of data signals for producing a respective spread spectrum data signal in response to the respective data signal and a respective function signal;
wherein each spreader includes two exclusive-OR gates;a first exclusive-OR gate having two inputs and one output, a first input connected to a respective inner signal generator and a second input receiving a respective data signal of the plurality of data signals; and a second exclusive-OR gate having two inputs and an output, a first input connected to the outer signal generator, a second input connected to the output of the first exclusive-OR gate, and the output connected to a signal combiner; a pilot signal generator for generating a pilot signal according to a function which is orthogonal to each function of the plurality of orthogonal functions; said signal combiner being connected to the plurality of spreaders and combining a plurality of spread spectrum data signals into a combined spread spectrum data signal; and a transmitter connected to the signal combiner for amplifying and transmitting the combined spread spectrum data signal.
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24. An apparatus for transmitting a plurality of data signals in a spread spectrum communication system, comprising:
a plurality of signal generators that provide a plurality of function signals, each function signal being generated according to a respective function of a plurality of orthogonal functions, wherein the plurality of signal generators comprise; first and second outer signal generators for generating first and second outer function signals representing, respectively, first and second outer functions, the first outer function being substantially orthogonal to the second outer function; multiple inner signal generators for generating a plurality of inner function signals, each inner function signal being generated according to a respective function of said plurality of orthogonal functions; a plurality of spreaders, each spreader being connected to a respective signal generator and receiving a respective data signal of the plurality of data signals for producing a respective spread spectrum data signal in response to the respective data signal and a respective function signal;
wherein each spreader includes three exclusive-OR gates;a first exclusive-OR gate having two inputs and one output, a first input connected to a respective inner signal generator and the second input receiving a respective data signal of the plurality of data signals; a second exclusive-OR gate having two inputs and an output, a first input connected to the first outer signal generator, a second input connected to the output of the first exclusive-OR gate, and the output being connected to a signal combiner; and a third exclusive-OR gate having two inputs and an output, the first input connected to the second outer signal generator, the second input connected to the output of the first exclusive-OR gate, and the output connected to the signal combiner; said signal combiner being connected to the plurality of spreaders and combining a plurality of spread spectrum data signals into a combined spread spectrum data signal; and a transmitter connected to the signal combiner for amplifying and transmitting the combined spread spectrum data signal.
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25. An apparatus for spread spectrum transmission of a plurality of data signals, comprising:
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a plurality of signal generators for providing a plurality of function signals, each function signal being provided according to a respective function of a plurality of orthogonal functions; a plurality of spreaders, each spreader connected to a respective signal generator and connected to receive a respective data signal of the plurality of data signals for spread spectrum generation of a respective spread spectrum data signal; a signal combiner connected to the plurality of spreaders for combining a plurality of spread spectrum data signals to generate a combined spread spectrum data signal including the plurality of spread spectrum data signals; a transmitter for amplifying and transmitting the combined spread spectrum data signal; and an outer code generator for generating an outer code signal, and wherein each spreader of the plurality of spreaders is further connected to the outer code generator for combining the outer code signal with a respective data signal and a respective function signal to produce a respective outer-coded spread spectrum data signal, and the signal combiner generates the combined spread spectrum data signal including a plurality of outer coded spread spectrum data signals.
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26. A communication modulation system, comprising:
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a pilot signal generator for generating a pilot signal according to a first orthogonal function selected from a set of orthogonal functions; a communication signal generator for receiving an input data signal, generating an orthogonal function signal according to a second orthogonal function selected from said set of orthogonal functions, wherein said second orthogonal function is different from said first orthogonal function, combining said orthogonal function signal with said input data signal and providing a resultant spread spectrum data signal; and an outer code generator for receiving said pilot signal and said spread spectrum data signal, generating a pseudorandom noise (PN) signal of a predetermined PN code, and combining said PN signal with said pilot signal and said spread spectrum data signal to produce corresponding PN-spread pilot and spread spectrum data signals.
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27. In a communication system in which a plurality of remote user stations communicate, via a radio link with a base station, with other user stations, said base station having a base station transceiver for communicating user station information signals to intended recipient remote user stations and for receiving remote user station communicated information signals for transfer to intended recipient user stations, said base station transceiver comprising:
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a base station transmitter for receiving at least one user station information signal, spreading each received user station information signal according to a respective predetermined orthogonal function, and transmitting said spread user station information signals as a base station communication signal; and a base station receiver for receiving and extracting from each remote user station transmitted remote user station communication signal a corresponding remote user station information signal for transfer to intended recipient user stations, wherein each remote user station includes a remote user station transceiver for communicating remote user station information signals to said base station for transfer to an intended recipient user station and for receiving and extracting from said base station communication signal respective user station information signals intended for said recipient remote user station, said remote user station transceiver comprising; a remote user station transmitter for receiving a remote user station information signal, converting said remote user station information signal into respective groups of orthogonal function signals, modulating and transmitting said orthogonal function signals as a remote user station communication signal; and a remote user station receiver for receiving and extracting from said base station communication signal said user station information signal intended for said remote user station.
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Specification