Abstract: Disclosed is a technology for performing a communication using an ultrasonic wave in an environment where an electromagnetic shielding is so severe that a wireless communication using an electromagnetic is difficult. In the environment where the electromagnetic shielding is severe, an ultrasonic terminal according to the present invention may transmit the ultrasonic wave using a solid structure as a medium, and an ultrasonic base station may receive the ultrasonic wave using the solid structure as the medium.

Abstract: There is provided a method of manufacturing a lens, including applying a second lens material to a first lens member made of a first lens material; aligning and fixing a light shielding member to the second lens material; and further applying the second lens material to the first lens member and performing curing thereon to complete a second lens member.

Abstract: There is provided a method of manufacturing a lens, including: forming a first lens layer having a protrusion and a groove part formed on a first surface thereof; forming a light shielding layer on the first surface; and forming a second lens on the first surface.

Abstract: A gain control apparatus in a receiver of multiband OFDM system includes: an amplifier amplifying a received signal based on a first auto gain control signal; an analog-to-digital converter for converting the amplified signal into a digital signal; band reception signal extractor for extracting a signal of a desired reception band from the converted digital signal for each reception band, and controlling gain of the extracted signal according to a second auto gain control signal; a reception power detector for detecting a reception power value of whole band from the converted digital signal; and a multiband integration baseband processor for generating the first auto gain control signal by using the detected reception power value of the whole band, and generating the second auto gain control signal to be provided to the band reception signal extraction units, resource allocation information for each band and a reception power for each reception band.

Abstract: There is provided a lens module. The lens module according to the present invention may include a lens unit including one or more lenses, each having a lens function part and a flange part forming a circumference of the lens function part; and a piezoelectric body disposed on the flange part so as to shield unnecessary light incident through the lens unit and performing autofocusing according to an application of voltage thereto.

Abstract: The predistorter may include: a predistortion filter predistorting an input signal to provide an output signal; a predistortion output estimation unit estimating the characteristics of a nonlinear device based on a signal processed by the nonlinear device and the output signal, and calculating a desired output signal of the predistortion filter by using the estimated characteristics of the nonlinear device; and an adaptive algorithm driving unit comparing the output signal with the desired output signal to output an error as a comparison result, calculating a filter coefficient according to which the calculated error is minimized, and providing the calculated filter coefficient to the predistortion filter in order to update a filter coefficient of the predistortion filter.

Abstract: A dual-band wideband local oscillation signal generator includes an oscillation unit, a division unit, a poly phase filter (PPF), a switch unit, and a single side band (SSB) mixer. The oscillation unit is configured to generate a positive in-phase (IP) signal, a negative in-phase (IN) signal, a negative quadrature-phase (QN) signal, and a positive quadrature-phase (QP) signal. The division unit is configured to divide frequencies of the IP signal and the IN signal and generate an RF signal. The PPF is configured to receive the IP signal and the IN signals inputted to the division unit, and generate an LO IP signal, an LO IN signal, an LO QP signal, and an LO QN signal. The switch unit is configured to receive the generated LO signals and select a high band frequency signal or a low band frequency signal.

Abstract: Provided are a method for measuring a variable bandwidth wireless channel, and a transmitter and a receiver therefor. The transmitter, includes: a pre-processing unit for performing variable over-sampling and band-limited filtering on an original sequence for measuring the wireless channel according to a pre-determined digital-to-analog (D/A) operation speed and measurement bandwidth, and creating and storing a probing sequence whose frequency is up-converted into a fixed transmitting intermediate frequency; and a real-time processing unit for transmitting a probing signal that the stored probing sequence is converted according to the D/A operation speed to the wireless channel.

Abstract: An apparatus and method of receiving signal are provided. The apparatus includes an amplifier that controls a gain according to a gain control signal and amplifies a received signal to generate an amplified signal, an analog-to-digital (A/D) converter that converts the amplified signal into a digital signal, a Fourier transform unit that performs Fourier transform of the digital signal to a frequency domain signal to generate a Fourier transform signal, a demodulator that demodulates the Fourier transform signal to generate a demodulated signal, and an automatic gain control unit that divides the Fourier transform signal into a noise period and a symbol period, calculates the signal level of the noise period based on the signal level of the symbol period, and generates the gain control signal according to the signal levels of the symbol period and the noise period.

Abstract: There is provided to an RF calibration apparatus and method for a multi-antenna mobile communication system, which calibrates a phase error and gain error of an RF path by calculating the minimum value of a sum of an initialized reference signal and a comparison signal by a simple operation and controlling the phase value of a phase converter and the gain of a variable amplifier on the RF path, in calibrating the RF path of a multi-antenna mobile communication system of a TDD (Time Division Duplexing) type or FDD (Frequency Division Duplexing) type.

Abstract: Provided are a method for measuring a variable bandwidth wireless channel, and a transmitter and a receiver therefore. The transmitter, includes: a pre-processing unit for performing variable over-sampling and band-limited filtering on an original sequence for measuring the wireless channel according to a pre-determined digital-to-analog (D/A) operation speed and measurement bandwidth, and creating and storing a probing sequence whose frequency is up-converted into a fixed transmitting intermediate frequency; and a real-time processing unit for transmitting a probing signal that the stored probing sequence is converted according to the D/A operation speed to the wireless channel.

Abstract: Provided is controlled-gain wideband feedback low-noise amplifier. The controlled-gain wideband feedback low-noise amplifier includes: a feedback amplifier configured to isolate an input signal and an output signal obtained by amplifying the input signal, feed back the output signal to the input signal to amplify wideband input signals, resonate a low-frequency band signal among the wideband input signals to amplify the low-frequency band signal among the wideband input signals, and be switched in accordance with a control signal to control an amplification gain of the low-frequency band signal among the wideband input signals; and a cascode amplifier configured to amplify a high-frequency band signal among the wideband signals inputted from the feedback amplifier, and be switched in accordance with a control signal to control an amplification gain of the high-frequency band signal among the wideband signals.

Abstract: A complementary metal-oxide semiconductor (CMOS) variable gain amplifier includes: a cascode amplifier including a common source field effect transistor and a common gate field effect transistor in a cascode structure; a first current generation unit connected in parallel to a drain of the common gate field effect transistor and configured to vary transconductance of the cascode amplifier; a second current generation unit connected to a common source of the cascode amplifier and configured to control a bias current of the cascode amplifier; a current control unit configured to generate a current control signal for the first and second current generation units; and a load stage connected in series to a drain of the cascode amplifier and configured to output an output current, which is varied by the overall transconductance of the cascode amplifier, as a differential output voltage.

Abstract: An operation control method in a base station of a wireless communication system includes: checking whether or not an allowed mobile station exists in coverage of the base station and overall coverage of base stations adjacent to the base station; and controlling the base station to perform transmission/reception at a predetermined period through a first discontinuous operation, when the allowed mobile station does not exist in the coverage of the base station and the overall coverage of the adjacent base stations.

Abstract: Disclosed is an apparatus for transmitting complex signals in a wireless communication system. The present invention, there is provided a method for controlling gain according to a magnitude change of output signals in a polar transmitter including an amplification unit having two or more amplification degrees, the method includes processes to control an output level of a modulated signal when a output-required power of transmission signals are less than a predetermined threshold value, and to perform a basic amplification through the amplification unit; to amplify the amplification unit at a first amplification level when the output-required power of the transmission signals is equal to or greater than a predetermined first threshold value and is less than a predetermined second threshold value; and to amplify the amplification unit at a second amplification level when the output-required power of the transmission signal is equal to or greater than the second threshold value.

Abstract: A pre-distortion apparatus of a power amplifier includes: a pre-distortion unit configured to generate a pre-distorted signal of an input signal by calculating a magnitude of the input signal and outputting a complex correction coefficient corresponding to the calculated magnitude of the input signal, and provide the generated pre-distorted signal as an input of the power amplifier; and a complex correct coefficient update unit configured to generate an error signal by comparing an output signal of the power amplifier with the input signal and updating the complex correction coefficient to minimize a magnitude of the generated error signal, wherein the pre-distortion unit provides a constant bias value corresponding to the magnitude of the input signal as a bias of the power amplifier while updating the complex correction coefficient.

Abstract: The present invention relates to transmitting/receiving apparatuses of a wideband radio channel measuring device using a multi-carrier. The wideband radio channel measuring device using the multi-carrier may measure radio channel characteristics at a frequency domain. Since the radio channel is measured at the frequency domain by the wideband radio channel measuring device using the multi-carrier, the channel characteristics may be simultaneously measured while maintaining a maximum Doppler measurement frequency at a predetermined level regardless of increase of the number of transmitting and receiving antennas, in an MIMO configuration.

Abstract: A repeating apparatus in a wireless communication system includes: a signal detection unit configured to receive a signal from a base station or a mobile station and detect strength of the signal; a control unit configured to compare the signal strength detected by the signal detection unit with signal strength predetermined by the system and provide comparison information; and an output signal control unit configured to receive the comparison information from the control unit and adjust and amplify gain of a signal transmitted to the base station or the mobile station.

Abstract: The method includes performing a wired back-to-back test by forming M wired paths connecting one of the N transmission antennas with the M reception antennas through M cables, separating ith digital data corresponding to an ith receiver wired path from the plurality of digital data stored in the receiver wherein i is a natural number greater than 1 and smaller than M, extracting a time delay by decimating the separated ith digital data and performing sliding correlation on the decimated data, and extracting attenuation and phase characteristics of the ith receiver wired path by extracting samples after the time delay among the decimated samples.

Abstract: A dual-band wideband local oscillation signal generator includes an oscillation unit, a division unit, a poly phase filter (PPF), a switch unit, and a single side band (SSB) mixer. The oscillation unit is configured to generate a positive in-phase (IP) signal, a negative in-phase (IN) signal, a negative quadrature-phase (QN) signal, and a positive quadrature-phase (QP) signal. The division unit is configured to divide frequencies of the IP signal and the IN signal and generate an RF signal. The PPF is configured to receive the IP signal and the IN signals inputted to the division unit, and generate an LO IP signal, an LO IN signal, an LO QP signal, and an LO QN signal. The switch unit is configured to receive the generated LO signals and select a high band frequency signal or a low band frequency signal.