Abstract: Disclosed is a method of controlling direction of radio-wave emission of a base-station transmitter which emits radio waves upon providing the radio waves with directivity in the direction of a receiver. Two antennas of a base station that are disposed at different positions transmit first and second signals that have been spread by mutually orthogonal spreading codes. A mobile station has a phase detector for receiving the first and second signals transmitted from respective ones of the antennas and obtaining a phase difference between these signals, and a direction estimator for calculating the direction of the mobile station, as seen from the base station, based upon the phase difference and for feeding back a signal representing the calculated direction from the mobile station to the base station. The transmitter of the base station transmits data toward the receiver in the calculated direction using a directional antenna.

Abstract: Disclosed is a distortion compensating apparatus for correcting the size of a distortion compensation coefficient in such a manner that a transmit signal that has undergone distortion compensation will not exceed the dynamic range of a DA converter. Specifically, before a distortion compensation coefficient hn+1(p) that has been calculated by a calculation unit is stored in a coefficient memory, an assumption is made that distortion compensation will be performed using the distortion compensation coefficient hn+1(p). Then it is determined beforehand whether a signal x(t)*hn+1(p) that will be obtained by this distortion compensation will exceed the limit of a DA converter. If the limit will be exceeded, the size of the distortion compensation coefficient is reduced by a correction unit, the corrected distortion compensation coefficient is stored in the memory and the transmit signal is corrected using the stored distortion compensation coefficient.

Abstract: The present invention provides a transmission device for predistorting a digital signal in order to compensate distortion, then amplifying and transmitting it. A digital input signal is converted to a first analog signal by a first D/A converter. Separately, the digital input signal is also subjected to predistortion. A compensating signal is then generated from the digital input signal and the predistorted signal. The compensating signal generated thereby is converted into a second analog signal by a second D/A converter. The first analog signal and second analog signal are then added, this addition operation giving a compensated analog transmission signal. This analog transmission signal is supplied to the amplifier for amplification, and then transmitted via an antenna.

Abstract: A disclosed quadrature modulation system inputs an inphase signal component and an orthogonal signal component, and outputs an output signal that is quadrature modulated by a quadrature modulator. The quadrature modulation system calculates a first cumulative total based on the inphase signal component input into the quadrature modulator and an inphase signal component of a feedback signal obtained from the output signal. The quadrature modulation system calculates a second cumulative total based on the orthogonal signal component input into the quadrature modulator and an orthogonal signal component of the feedback signal. Based on the first and the second cumulative totals, a time difference between the inphase signal component and the orthogonal signal component is determined. The inphase signal component and the orthogonal signal component to be provided to the quadrature modulator are adjusted based on the time difference such that the time difference is compensated for.

Abstract: Disclosed is a distortion compensating apparatus for correcting the size of a distortion compensation coefficient in such a manner that a transmit signal that has undergone distortion compensation will not exceed the dynamic range of a DA converter. Specifically, before a distortion compensation coefficient hn+1(p) that has been calculated by a calculation unit is stored in a coefficient memory, an assumption is made that distortion compensation will be performed using the distortion compensation coefficient hn+1(p). Then it is determined beforehand whether a signal x(t)*hn+1(p) that will be obtained by this distortion compensation will exceed the limit of a DA converter. If the limit will be exceeded, the size of the distortion compensation coefficient is reduced by a correction unit, the corrected distortion compensation coefficient is stored in the memory and the transmit signal is corrected using the stored distortion compensation coefficient.

Abstract: Disclosed is a phase calibration method for inserting a calibration signal (SC) into main signals (SM1 to SMn) of a plurality of branches in turn, estimating the phase characteristic of an analog circuit to which a respective one of the main signals is input and calibrating the phase of each main signal. The method includes steps of outputting a first combined signal obtained by combining output signals from the analog circuits (62a to 62n) in all branches, outputting a second combined signal obtained by combining the main signals in all branches, extracting the calibration signal by removing the second combined signal from the first combined signal in a calibration signal extracting unit (64), estimating the phase characteristics of the analog circuits, to which the main signals having the inserted calibration signal are input, based upon a change in phase of the calibration signal, and subjecting the main signals to phase adjustment having characteristics that are opposite the phase characteristics.

Abstract: First, a digital section constituting a linearizer is activated. Then, a feedback loop for updating a distortion compensation coefficient is opened. Then, the analog section on the antenna side is activated from an ADC, including a PA, etc., or a DAC. Then, both the ATT value of an ATT installed in a feedback route for updating the distortion compensation coefficient and the signal delay amount of a signal delay unit are adjusted to make a state such that the distortion compensation coefficient can be accurately updated. Then, the feedback loop is closed, a distortion compensation table having the distortion compensation coefficient as an entry is generated and after the generation is completed, the operation shifts to the normal operation.

Abstract: A distortion compensation apparatus of the present invention is used in a transmitter that produces and outputs a second signal from a first signal. This apparatus comprises a delay unit for delaying a feedback signal obtained from by the second signal; and a delay control unit for determining a delay quantity of said delay means so that a timing difference between a reference signal obtained from the first signal and the feedback signal delayed by the delay unit is made small. The delay control unit limits the delay quantity within a predetermined limit value.

Abstract: The distortion compensator which compensates the nonlinearity of a power amplifier in a radio communication device stops the operation of updating the automatic phase adjustment, automatic delay adjustment, equalizer adjustment, and distortion compensation table when something wrong is detected in the input to a distortion compensation unit such as a reference signal, feedback signal, address of the distortion compensation table, and phase value so that the distortion compensation coefficients may not be improperly updated.

Abstract: Disclosed is an adaptive control apparatus having an error calculation unit for calculating the difference between a reference signal and a feedback signal, and an adaptive controller for applying adaptive control so as to diminish the difference and causing the result of adaptive control to be reflected in the reference signal. The adaptive control apparatus has a delay unit for delaying at least one of the reference signal and feedback signal by a set delay time in such a manner that the reference signal and feedback signal will be input simultaneously to the arithmetic unit; a frequency-component detecting unit for detecting a frequency component of the reference signal; a delay-time acquisition unit for acquiring delay time conforming to the frequency component; and a delay-time setting unit for setting the acquired delay time in the delay unit.

Abstract: In a distortion compensation device which uses distortion compensation coefficients to subject distortion compensation processing to an input signal and supply the result of the distortion compensation processing to a distorting device, calculates the distortion compensation coefficients based on the input signal before distortion compensation and the feedback signal fed back from the output side of the distorting device, and stores the calculated distortion compensation coefficients in association with the input signal, (1) the feedback signal is AD-converted; (2) the AD-converted output is subjected to fast Fourier transform (FFT) processing; (3) the FFT calculation result is used to calculate the value of either the signal-to-noise ratio SNR, or the adjacent channel leakage power ratio ACLR, or the noise level; (4) the delay time occurring in the distorting device and feedback loop is adjusted such that the difference between the above calculated value at the current time and the above calculated value at

Abstract: Disclosed is a method of controlling direction of radio-wave emission of a base-station transmitter which emits radio waves upon providing the radio waves with directivity in the direction of a receiver. Two antennas of a base station that are disposed at different positions transmit first and second signals that have been spread by mutually orthogonal spreading codes. A mobile station has a phase detector for receiving the first and second signals transmitted from respective ones of the antennas and obtaining a phase difference between these signals, and a direction estimator for calculating the direction of the mobile station, as seen from the base station, based upon the phase difference and for feeding back a signal representing the calculated direction from the mobile station to the base station. The transmitter of the base station transmits data toward the receiver in the calculated direction using a directional antenna.

Abstract: A distortion compensating apparatus calculates a distortion compensation coefficient in such a manner that a difference signal between a reference signal, which is a transmit signal, and a feedback signal will be diminished, updates an old distortion compensation coefficient by the calculated distortion compensation coefficient and applies distortion compensation to the transmit signal based upon this distortion compensation coefficient. In this apparatus, a phase correcting interval, which is for correcting the phase difference between the reference signal and the feedback signal, and a distortion compensation coefficient updating interval are generated alternately, a correction is applied so as to null the phase difference in the phase correcting interval, and the distortion compensation coefficient is updated in the distortion compensation coefficient updating interval.

Abstract: A phase ?I1, . . . , ?Q1, . . . uniquely determined for each channel is assigned to a carrier for each channel used when data I1 . . . , Q1, . . . , to be distributed among different channels are modulated. By appropriately modifying the phase of a carrier for each channel, signal points can be located in a narrower region than in a conventional region, and thereby the difference in amplitude between a signal point with a minimum amplitude and a signal point with a maximum amplitude can be reduced. Thus, the amplitude range of a signal to be covered by an amplifier for transmitting a transmission signal is reduced, and thereby an amplifier with a linearity that is not high can be used for the amplifier. Accordingly, even if the number of signal points increase, there is no need to use a large high-power amplifier, and thereby the small power and small size of the apparatus can be realized.

Abstract: Disclosed is a method of controlling direction of radio-wave emission of a base-station transmitter which emits radio waves upon providing the radio waves with directivity in the direction of a receiver. Two antennas of a base station that are disposed at different positions transmit first and second signals that have been spread by mutually orthogonal spreading codes. A mobile station has a phase detector for receiving the first and second signals transmitted from respective ones of the antennas and obtaining a phase difference between these signals, and a direction estimator for calculating the direction of the mobile station, as seen from the base station, based upon the phase difference and for feeding back a signal representing the calculated direction from the mobile station to the base station. The transmitter of the base station transmits data toward the receiver in the calculated direction using a directional antenna.

Abstract: The present invention reduces the scale of circuitry and shortens the code phase detection time needed to achieve initial synchronization. In a correlator for calculating correlation between a received spreading code contained in a received spread-spectrum signal and a reference spreading code, a combined code generator is included. The combined code generator outputs a combined spreading code by weighting and combining a plurality of phase-shifted reference spreading codes A1-AM. Further, an arithmetic circuit calculates correlation between the received spreading code and the plurality of phase-shifted reference spreading codes simultaneously. A phase detection circuit detects the phase difference between the received spreading code and a reference spreading code, namely the phase of the received spreading code from the results of the arithmetic operation.

Abstract: A code multiplexing transmitting apparatus spread-spectrum modulates transmission data of a plurality of channels by spreading codes that differ from one another, combines the spread-spectrum signals of each of the channels and transmits the resultant spread-spectrum modulated signal. A spread-spectrum modulating unit for each channel includes a phase shifter for shifting, by a predetermined angle channel by channel, the phase of a position vector of the spread-spectrum modulated signal of each channel. As the result of such phase control, the phases of pilot signal portions of the spread-spectrum modulated signals of the respective channels are shifted relative to one another so that the peak values of the code-multiplexed signal can be suppressed.

Abstract: In a distortion compensation device which uses distortion compensation coefficients to subject distortion compensation processing to an input signal and supply the result of the distortion compensation processing to a distorting device, calculates the distortion compensation coefficients based on the input signal before distortion compensation and the feedback signal fed back from the output side of the distorting device, and stores the calculated distortion compensation coefficients in association with the input signal, (1) the feedback signal is AD-converted; (2) the AD-converted output is subjected to fast Fourier transform (FFT) processing; (3) the FFT calculation result is used to calculate the value of either the signal-to-noise ratio SNR, or the adjacent channel leakage power ratio ACLR, or the noise level; (4) the delay time occurring in the distorting device and feedback loop is adjusted such that the difference between the above calculated value at the current time and the above calculated value at

Abstract: Disclosed is a method of controlling direction of radio-wave emission of a base-station transmitter which emits radio waves upon providing the radio waves with directivity in the direction of a receiver. Two antennas of a base station that are disposed at different positions transmit first and second signals that have been spread by mutually orthogonal spreading codes. A mobile station has a phase detector for receiving the first and second signals transmitted from respective ones of the antennas and obtaining a phase difference between these signals, and a direction estimator for calculating the direction of the mobile station, as seen from the base station, based upon the phase difference and for feeding back a signal representing the calculated direction from the mobile station to the base station. The transmitter of the base station transmits data toward the receiver in the calculated direction using a directional antenna.

Abstract: A code multiplexing transmitting apparatus spread-spectrum modulates transmission data of a plurality of channels by spreading codes that differ from one another, combines the spread-spectrum signals of each of the channels and transmits the resultant spread-spectrum modulated signal. A spread-spectrum modulating unit for each channel includes a phase shifter for shifting, by a predetermined angle channel by channel, the phase of a position vector of the spread-spectrum modulated signal of each channel. As the result of such phase control, the phases of pilot signal portions of the spread-spectrum modulated signals of the respective channels are shifted relative to one another so that the peak values of the code-multiplexed signal can be suppressed.