Abstract:
The present invention relates to a predistortion (PD) apparatus for linearization of a power amplifier of a transmitter in a wireless communication system and a method thereof, and more specifically, to a low-cost digital PD apparatus which has a PD function and uses an envelope detection feedback method and the method thereof. The PD apparatus simplify the feedback method needed in a transmitter with a PD function to an envelope detection feedback. The present invention provides the low-cost digital PD apparatus using the envelope detection feedback method and the method thereof to reduce the implementation complexity of a feedback loop required for implementing a PD function to minimize the cost and volume of the implementation by applying a PD technique to maximize the efficiency of a power amplifier in a system linearizing the power amplifier.
Abstract:
본 발명은, 적어도 하나 이상의 중계기 및 상기 중계기에 접속된 다수의 단말로 구성된 중계기 네트워크에 있어서 각 단말 간 데이터 교환 방법 및 상기 각 단말 간 데이터 교환을 제어하는 방법에 관한 것이다. 본 발명에 따르면, 다수의 단말에서 중계기를 통한 데이터 교환이 가능함에 따라, 중계기 네트워크의 성능 향상 및 향후 네트워크 확장에 있어서 유연성 및 효율성을 확보하며, 단말 채널 상황에 따른 중계기 네트워크의 성능 저하를 방지하는 효과도 있다.
Abstract:
PURPOSE: An adaptive pre-distortion method is provided to have low complexity by forming a pre-distortion structure which compensates a nonlinear property based on a modeling. CONSTITUTION: A predistorter outputs an output signal by receiving an input signal. A power amplifier outputs an amplified output signal by receiving the output signal. The power amplifier executes a modeling from the inputted output signal and the amplified output signal. The amplitude function of a nonlinear characteristic function is modeled to a piecewise linear function. A phase function is modeled to a piecewise constant function. An estimated polynomial coefficient is extracted by using the property of the power amplifier after assessing the property of the amplifier. The output signal is compensated.
Abstract:
A receiving device of a duplex transmission system and an interference eliminating method thereof using a timing recovery based on amplification and transmission relay are provided to perform timing recovery about data in an over sampling region and remove the interference eliminating signal. A receiver(110) receives interference signal and data signal from amplification and transmission relay. An ADC(Analog Digital Converter) samples reception signal suitable for time delay among interference signal and data signal. A signal estimation unit uses the sampled reception signal and PSF(Pulse Shaping Filter) and estimates interference signal. An interference cancellation unit removes the interference signal in the received signal passing through ADC. A digital reception unit performs the timing recovery about the signal removing the interference signal.
Abstract:
PURPOSE: A device for estimating and compensating I/Q mismatch is provided to estimate channels, I/Q mismatch, and DC offset in a time region by using LSs(Least Squares), and to compensate the I/Q mismatch and the DC offset by using the estimated value, thereby minimizing training data groups. CONSTITUTION: An estimator(10) estimates I/Q mismatch, DC offset, and a channel coefficient by using LSs from a receiving signal corresponding to training data. A compensator(70) sequentially removes the DC offset and the I/Q mismatch from the receiving signal by using an estimated value, and consists of adders(20,50), a multiplier(40), and a complex conjugate generator(30). The adder(20) removes the DC offset by using the DC offset estimated value. The complex conjugate generator(30) generates a complex conjugate signal of the receiving signal whose DC offset is removed. The multiplier(40) multiplies an I/Q mismatch estimated value by the generated signal. The adder(50) removes the I/Q mismatch.
Abstract:
PURPOSE: A device for estimating and compensating I/Q mismatch is provided to estimate channels, I/Q mismatch, and DC offset in a time region by using LSs(Least Squares), and to compensate the I/Q mismatch and the DC offset by using the estimated value, thereby minimizing training data groups. CONSTITUTION: An estimator(10) estimates I/Q mismatch, DC offset, and a channel coefficient by using LSs from a receiving signal corresponding to training data. A compensator(70) sequentially removes the DC offset and the I/Q mismatch from the receiving signal by using an estimated value, and consists of adders(20,50), a multiplier(40), and a complex conjugate generator(30). The adder(20) removes the DC offset by using the DC offset estimated value. The complex conjugate generator(30) generates a complex conjugate signal of the receiving signal whose DC offset is removed. The multiplier(40) multiplies an I/Q mismatch estimated value by the generated signal. The adder(50) removes the I/Q mismatch.
Abstract:
본 발명은 PSK 계열 신호의 동기 복조시 제한된 오실레이터의 정확도나 도플러 영향은 반송파 주파수 오차를 발생시킬 수 있고 이는 복조기의 심각한 성능 저하를 가져 올 수는데 이러한 주파수 오차를 보정하는 방법에 관한 것으로, 이는 수신기의 성능을 개선시킬 수 있으며 오실레이터의 정확도에 대한 요구 조건을 완화시킬 수 있는 주파수 선택적 페이딩 채널에서의 새로운 주파수 추정기를 제안한다. 먼저 기존 AWGN(Additive white Gaussian noise)을 위한 추정기를 확장하여 채널 임펄스 응답이 알려져 있다는 가정하에 기반 추정기를 제안한다. 이 기반 추정기는 특별한 종류의 훈련신호, 백색 타입 신호라 불리는 훈련신호의 도움으로 제안된 추정기로 변형된다. 제안된 주파수 추정기는 백색 타입의 훈련신호가 사용되면 어떤 채널 정보도 필요로 하지 않는다.
Abstract:
본 발명은 복수 개의 송신 안테나를 갖는 MIMO 송신기에서 송신 안테나 수보다 적은 디지털-아날로그 변환기(Digital-Analog Converter: DAC)를 사용하는 아날로그 신호 변환 방법, 복수 개의 수신 안테나를 갖는 MIMO 수신기에서 수신 안테나 수보다 적은 아날로그-디지털 변환기(Analog-Digital Converter: ADC)를 사용하는 디지털 신호 변환 방법 및 이 방법을 적용한 시스템에 관한 것이다. MIMO 송신기 및 MIMO 수신기는 체인그룹마다 하나의 데이터 변환기를 사용하기 위하여 체인별로 신호 지연을 주면서, 신호를 스위칭하여 하나의 테이터 변환기에 전달하는 것이 특징이다.
Abstract:
PURPOSE: A digital predistortion device and a method thereof are provided to reduce implementation complexity for implementing a predistortion function by replacing an envelope detection method for a modulation function of an existing feedback loop required for the predistortion function. CONSTITUTION: A first envelope detector(110) converts the output of an power amplifier into a baseband signal. A second envelop detector(120) converts a difference between the input and the output of the power amplifier into the baseband signal. An operating unit(130) calculates an absolute value of the output of the power amplifier by using the baseband signal of the first envelope detector. The operating unit estimates a phase changed by the power amplifier by using the baseband signal of the second envelope detector. The operating unit calculates a predistortion coefficient of the power amplifier. The operating unit transmits the calculated predistortion coefficient to a predistortion device. [Reference numerals] (130) Operating unit; (30) Modulator; (AA) Envelope detector; (BB) Attenuator;