Up-link access apparatus in direct sequence code division multiple access system
First Claim
1. An up-link access apparatus in a direct sequence spread spectrum code division multiple access system having a base station and a plurality of mobile stations, said apparatus comprising:
- a transmitter for mixing base band data with a pseudo-noise code unique to a first of said plurality of mobile stations to generate a pseudo-noise code modulated signal, said transmitter then mixing said pseudo-noise code modulated signal with a carrier signal having a frequency shifted by an identification frequency unique to said first of said plurality of mobile stations to output a spread spectrum signal for transmission to said base station; and
a receiver of said base station for mixing a demodulation carrier comprised of said pseudo-noise code and said carrier signal with said spread spectrum signal from said transmitter to output a mixed signal, said receiver then integrating said mixed signal to output an integrated signal and demodulating said integrated signal to output a digital signal.
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Accused Products
Abstract
Disclosed is a link access apparatus of a CDMA system using a DS/SS communication method, and more particularly an up-link access apparatus which overcomes a near/far problem occurring when mobile stations and a base station perform multiple access communication using code division. An up-link access apparatus in a DS/SS-CDMA system has a transmitter for mixing data to be transmitted to a base station with a PN code unique to that mobile station to thereby PN code modulate the data. The transmitter then mixes the PN code modulated data with a carrier having a frequency that is shifted by an identification frequency to thereby output a spread spectrum signal. The apparatus further includes a receiver for mixing a demodulation carrier made up of the PN code and the identification frequency with the spread spectrum signal from the transmitter to thereby output a mixed signal. The mixed signal is then integrated according to a period having a reciprocal corresponding to the identification frequency, demodulated and output as a digital signal.
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Citations
20 Claims
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1. An up-link access apparatus in a direct sequence spread spectrum code division multiple access system having a base station and a plurality of mobile stations, said apparatus comprising:
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a transmitter for mixing base band data with a pseudo-noise code unique to a first of said plurality of mobile stations to generate a pseudo-noise code modulated signal, said transmitter then mixing said pseudo-noise code modulated signal with a carrier signal having a frequency shifted by an identification frequency unique to said first of said plurality of mobile stations to output a spread spectrum signal for transmission to said base station; and a receiver of said base station for mixing a demodulation carrier comprised of said pseudo-noise code and said carrier signal with said spread spectrum signal from said transmitter to output a mixed signal, said receiver then integrating said mixed signal to output an integrated signal and demodulating said integrated signal to output a digital signal. - View Dependent Claims (2, 3, 4, 5)
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6. A method for perforating up-link access in a direct sequence spread spectrum code division multiple access system having a base station and a plurality of mobile stations, said method comprising the steps of:
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mixing base band data to be transmitted to said base station with a pseudo-noise code unique to a first one of said plurality of mobile stations to generate a pseudo-noise code modulated signal; generating an up-link carrier frequency comprised of a fixed carrier frequency shifted by an identification frequency unique to said first one of said plurality of mobile stations, each one of said plurality of mobile stations having a different said identification frequency; mixing said pseudo-noise code modulated signal with said up-link carrier frequency to generate a spread spectrum signal; and transmitting said spread spectrum signal from an output port of said first one of said plurality of mobile stations to said base station. - View Dependent Claims (7)
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8. A system for performing up-link access using direct access spread spectrum communication, comprising:
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a base station; a plurality of mobile stations; transmission means for transmitting data from a first of said plurality of mobile stations to said base station by mixing a pseudo-noise code modulated signal with an up-link carrier frequency to generate said data for transmission to said base station, said up-link carrier frequency comprised of a fixed carrier frequency shifted by a first identification frequency unique to said first of said plurality of mobile stations; and receiving means for receiving at said base station said data transmitted from said transmission means, mixing said data with a demodulation carrier to generate a mixed signal and integrating said mixed signal according to a specified period, said specified period having a reciprocal equal to an integer multiple of said first identification frequency. - View Dependent Claims (9, 10, 11, 12)
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13. An up-link access apparatus in a direct sequence spread spectrum code division multiple access system having a base station and a plurality of mobile stations, said apparatus comprising:
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a transmitter for mixing base band data with a pseudo-noise code to generate a pseudo-noise code modulated signal, said transmitter then mixing said pseudo-noise code modulated signal with a carrier signal having a frequency shifted by an identification frequency unique to a first of said plurality of mobile stations to output a spread spectrum signal for transmission to said base station; and a receiver of said base station for mixing a demodulation carrier comprised of said pseudo-noise code and said carrier signal with said spread spectrum signal from said transmitter to output a mixed signal, said receiver then integrating said mixed signal to output an integrated signal and demodulating said integrated signal to output a digital signal. - View Dependent Claims (14, 15, 16)
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17. A method for performing up-link access in a direct sequence spread spectrum code division multiple access system having a base station and a plurality of mobile stations, said method comprising the steps of:
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mixing base band data to be transmitted to said base station with a pseudo-noise code to generate a pseudo-noise code modulated signal; generating an up-link carrier frequency comprised of a fixed carrier frequency shifted by an identification frequency unique to a first one of said plurality of mobile stations, each one of said plurality of mobile stations having a different said identification frequency; mixing said pseudo-noise code modulated signal with said up-link carrier frequency to generate a spread spectrum signal; and transmitting said spread spectrum signal from an output port of said first one of said plurality of mobile stations to said base station. - View Dependent Claims (18)
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19. A system for performing up-link access using direct access spread spectrum communication, comprising:
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a base station; a plurality of mobile stations; transmission means for transmitting data from said plurality of mobile stations to said base station by mixing pseudo-noise code modulated signals with up-link carrier frequencies to generate said data for transmission to said base station, each one of said up-link carrier frequencies comprised of a fixed carrier frequency shifted by an identification frequency unique to a respective one of said plurality of mobile stations; and receiving means for receiving at said base station said data transmitted from said transmission means, mixing said data with demodulation carriers to generate mixed signals and integrating said mixed signals according to specified periods, said specified periods each having a reciprocal equal to an integer multiple of a corresponding said identification frequency. - View Dependent Claims (20)
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Specification