Code division multiple access mobile communication system
First Claim
1. A code division multiple access mobile communication system for spreading, modulating and transmitting a pilot signal along with data into radio frequency band signals, demodulating and despreading the received radio frequency band signals into a received pilot signal and received data, and generating a phase correction signal from the received pilot signal so that a phase error of the received data is corrected by use of said phase correction signal during detection, the system comprising:
- a plurality of mobile stations and a base station, said base station establishing up and down links in conjunction with said plurality of mobile stations;
each of said plurality of mobile stations having a detection circuit including;
a voltage-controlled oscillator for supplying a carrier to a radio frequency quadrature demodulator demodulating the received radio frequency band signals;
an averaging circuit for averaging a first step phase correction signal generated from the received pilot signal and outputting said phase correction signal; and
a frequency controller for detecting a frequency error from said first step phase correction signal, said frequency controller further generating from said frequency error a control signal to control the frequency of the carrier generated by said voltage-controlled oscillator, wherein said frequency controller comprises;
a phase change generating circuit for generating a phase change based on said frequency error derived from said first step phase correction signal and a signal preceding said first step phase correction signal by a predetermined delay time; and
an integrating circuit for integrating said phase change and outputting the integrated result as said control signal.
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Accused Products
Abstract
A code division multiple access (CDMA) mobile communication system with improvements to permit stable reception with a minimum of bit error. The system comprises a voltage-controlled oscillator for supplying a carrier to a radio frequency quadrature demodulator, and a frequency controller for detecting a frequency error from a phase correction signal of the first step to generate a control signal that controls the oscillator. The frequency controller includes an extracting circuit and an integrating circuit. The extracting circuit extracts a phase change based on the frequency error derived from the phase correction signal of the first step and from a signal preceding that signal by a predetermined delay time. The integrating circuit integrates the phase change and outputs the integrated result as the control signal. The predetermined delay time is preferably set within a range not exceeding the delay time needed for averaging by an averaging circuit that receives the phase correction signal of the first step and outputs a phase correction signal. The carrier to a radio frequency quadrature modulator is preferably supplied from the voltage-controlled oscillator.
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Citations
12 Claims
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1. A code division multiple access mobile communication system for spreading, modulating and transmitting a pilot signal along with data into radio frequency band signals, demodulating and despreading the received radio frequency band signals into a received pilot signal and received data, and generating a phase correction signal from the received pilot signal so that a phase error of the received data is corrected by use of said phase correction signal during detection, the system comprising:
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a plurality of mobile stations and a base station, said base station establishing up and down links in conjunction with said plurality of mobile stations; each of said plurality of mobile stations having a detection circuit including; a voltage-controlled oscillator for supplying a carrier to a radio frequency quadrature demodulator demodulating the received radio frequency band signals; an averaging circuit for averaging a first step phase correction signal generated from the received pilot signal and outputting said phase correction signal; and a frequency controller for detecting a frequency error from said first step phase correction signal, said frequency controller further generating from said frequency error a control signal to control the frequency of the carrier generated by said voltage-controlled oscillator, wherein said frequency controller comprises; a phase change generating circuit for generating a phase change based on said frequency error derived from said first step phase correction signal and a signal preceding said first step phase correction signal by a predetermined delay time; and an integrating circuit for integrating said phase change and outputting the integrated result as said control signal. - View Dependent Claims (2, 3, 4)
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5. A code division multiple access mobile communication system for transmitting and receiving data spread by a spread code over a radio frequency band, the system comprising:
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a plurality of mobile stations and a base station; said plurality of mobile stations each having a detection circuit including; a temporary judge circuit acting when each of a sign of a cosine component and a sign of a sine component of despread data is found to be inverted one symbol later, said temporary judge circuit thereupon inverting the signs of the components individually and outputting the sign-inverted components, said temporary judge circuit further outputting the components uninverted when the signs thereof are found to be uninverted one symbol later; a frequency controller for generating a phase change based on the frequency error derived from the output signal of said temporary judge circuit and from a signal preceding said output signal by a predetermined delay time, said frequency controller further integrating said phase change and outputting the integrated result as a control signal; a voltage-controlled oscillator for receiving said control signal as a signal to control an oscillation frequency; and a radio frequency quadrature demodulator for receiving the output signal of said voltage-controlled oscillator as a carrier to demodulate received radio frequency band signals; wherein said base station establishes up and down links in conjunction with said plurality of mobile stations.
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6. A mobile station for use with a code division multiple access mobile communication system for spreading, modulating and transmitting a pilot signal along with data into radio frequency band signals, demodulating and despreading the received radio frequency band signals into a received pilot signal and received data and generating a phase correction signal from the received pilot signal so that a phase error of the received data is corrected by use of said phase correction signal from the received pilot signal so that a phase error of the received data is corrected by use of said phase correction signal during detection,
said mobile station having a detection circuit comprising: -
a voltage-controlled oscillator for supplying a carrier to a radio frequency quadrature demodulator demodulating the received radio frequency band signals; an averaging circuit for averaging a first step phase correction signal generated from the received pilot signal and outputting said phase correction signal; and a frequency controller for detecting a frequency error from said first step phase correction signal, said frequency controller further generating from said frequency error a control signal to control the frequency of said voltage-controlled oscillator, wherein said frequency controller comprises; a phase change generating circuit for generating a phase change based on said frequency error derived from said first step phase correction signal and from a signal preceding said first step phase correction signal by a predetermined delay time; and an integrating circuit for integrating said phase change and outputting the integrated result as said control signal. - View Dependent Claims (7, 8, 9)
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10. A mobile station for use with a code division multiple access mobile communication system for transmitting and receiving data spread by a spread code over a radio frequency band, said mobile station having a detection circuit comprising:
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a temporary judge circuit acting when each of a sign of a cosine component and a sign of a sine component of despread data is found to be inverted one symbol later, said temporary judge circuit thereupon inverting the signs of the components individually and outputting the sign-inverted components, said temporary judge circuit further outputting the components uninverted when the signs thereof are found to be uninverted one symbol later; a frequency controller for generating a phase change based on the frequency error derived from the output signal of said temporary judge circuit and from a signal preceding said output signal by a predetermined delay time, said frequency controller further integrating said phase change and outputting the integrated result as a control signal; a voltage-controlled oscillator for receiving said control signal as a signal to control an oscillation frequency; and a radio frequency quadrature demodulator for receiving the output signal of said voltage-controlled oscillator as a carrier to demodulate received radio frequency band signals.
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11. A code division multiple access mobile communication system for spreading, modulating and transmitting a pilot signal along with data into radio frequency band signals, demodulating and despreading the received radio frequency band signals into a received pilot signal and received data and generating a phase correction signal from the received pilot signal so that a phase error of the received data is corrected by use of said phase correction signal from the received pilot signal so that a phase error of the received data is corrected by use of said phase correction signal during detection, the system comprising:
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a plurality of mobile stations and a base station, said base station establishing up and down links in conjunction with said plurality of mobile stations; each of said plurality of mobile stations having a detection circuit including; a voltage-controlled oscillator for supplying a carrier to a radio frequency quadrature demodulator demodulating the received radio frequency band signals; an averaging circuit for averaging a first step phase correction signal generated from the received pilot signal and outputting said phase correction signal; and means for detecting a frequency error from said first step phase correction signal, and for generating from said frequency error a control signal to control the frequency of the carrier generated by said voltage-controlled oscillator, wherein said means for detecting comprises; means for generating a phase change based on said frequency error derived from said first step phase correction signal and from a signal preceding said first step phase correction signal by a predetermined delay time; and means for integrating said phase change and outputting the integrated result as said control signal.
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12. A mobile station for use with a code division multiple access mobile communication system for spreading, modulating and transmitting a pilot signal along with data into radio frequency band signals, demodulating and despreading the received radio frequency band signals into a received pilot signal and received data and generating a phase correction signal from the received pilot signal so that a phase error of the received data is corrected by use of said phase correction signal during detection,
said mobile station having a detection circuit comprising: -
a voltage-controlled oscillator for supplying a carrier to a radio frequency quadrature demodulator demodulating the received radio frequency band signals; an averaging circuit for averaging a first step phase correction signal generated from the received pilot signal and outputting said phase correction signal; and means for detecting a frequency error from said first step phase correction signal, and for generating from said frequency error a control signal to control the frequency of said voltage-controlled oscillator, wherein said means for detecting comprises; means for generating a phase change based on said frequency error derived from said first step phase correction signal and from a signal preceding said first step phase correction signal by a predetermined delay time; and means for integrating said phase change and outputting the integrated result as said control signal.
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Specification