Abstract:
An apparatus and a method for synchronizing a symbol of an OFDM wireless communication system are provided to facilitate synchronization acquisition of the symbol by obtaining a correlation coefficient with the preamble of the receiver by simplifying the data of the preamble of the transmitter used in the correlation coefficient calculation. A data converter(21) converts the preamble received from a transmitter into digital data of N(1
Abstract:
An automatic gain control apparatus and an automatic gain control method of an OFDM wireless communication system and a computer-readable recording medium having a program performing function for embodying the same are provided to control a gain of power within one preamble frequently by controlling the gain of the power automatically. A variable gain amplification unit(210) controls a gain of an input signal. An ADC(220) converts an output of the variable gain amplification unit to a digital signal. A symbol synchronization unit(260) extracts synchronous information from an output of the ADC. A maximum value sample extraction unit(230) divides a preamble and counts a sample number having a maximum ADC level value of output signals of the ADC on the basis of the synchronous information. A gain control signal decision unit(240) decides the gain control value of the variable gain amplification unit by using a maximum value sample number. A control unit(250) converts a gain control value of the gain control signal decision to an analog signal and transfers the analog signal to the variable gain amplification unit.
Abstract:
A pseudo-orthogonal code transmission and reception system is provided to transmit more information bits with a pseudo-orthogonal code of the same length as an orthogonal code. A pseudo-orthogonal code transmission system includes a serial to parallel converter, and a pseudo-orthogonal code memory. The serial to parallel converter converts serial transmission data into parallel data of 9 bits. The pseudo-orthogonal code memory receives the parallel data from the serial to parallel converter, and outputs a pseudo-orthogonal code of 16 bits by using the received parallel data as an address.
Abstract:
A transmission apparatus of a high speed broad band modem for minimizing a quantization error is provided to minimize the quantization error by improving a calculation method of an IFFT(Inverse Fast Fourier Transform). A transmission apparatus of a high speed broad band modem for minimizing a quantization error includes a scrambler, a convolution encoder, an interleaver, a mapper and an IFFT. The IFFT has n stages, and receives a multiplied result of the output of the mapper and (n x m) squares of 2. The IFFT divides the calculation value by m squares of 2 whenever n-1 stages are passed. If a data transmission mode is a QPSK(Quadrature Phase Shift Key), the transmission apparatus multiplies the output of the IFFT by 1/square. If a data transmission mode is a DCM, the transmission apparatus performs the normalization of a power classified by sub-carriers by multiplying the output value of the IFFT by 1/square.
Abstract:
A transmission apparatus of a high speed broad band modem for minimizing a quantization error is provided to minimize the quantization error by improving a calculation method of an IFFT(Inverse Fast Fourier Transform). A transmission apparatus of a high speed broad band modem for minimizing a quantization error includes a scrambler, a convolution encoder, an interleaver, a mapper and an IFFT. The IFFT has n stages, and receives a multiplied result of the output of the mapper and (n x m) squares of 2. The IFFT divides the calculation value by m squares of 2 whenever n-1 stages are passed. If a data transmission mode is a QPSK(Quadrature Phase Shift Key), the transmission apparatus multiplies the output of the IFFT by 1/square. If a data transmission mode is a DCM, the transmission apparatus performs the normalization of a power classified by sub-carriers by multiplying the output value of the IFFT by 1/square.
Abstract:
본 발명은 입력 신호의 이득을 조절하는 가변 이득 증폭부와, 상기 가변 이득 증폭부의 출력을 디지털 신호로 변조하는 ADC와, 상기 ADC의 출력을 입력받아 동기 정보를 추출하는 심볼 동기 발생부와, 프리앰블을 분할하고 분할된 상기 프리앰블에 대해서 상기 동기 정보를 기초로 상기 ADC 출력 신호 중에서 ADC 레벨의 최대치를 갖는 샘플 수를 카운트하는 최대치 샘플 계산부와, 상기 최대치 샘플 계산부에 의해서 계산된 최대치 샘플 수를 이용하여 상기 가변 이득 증폭부의 이득 조절값을 결정하는 이득 조절 신호 결정부와, 상기 이득 조절 신호 결정부에 의해서 계산된 상기 이득 조절값을 아날로그 신호로 변환하여 상기 가변 이득 증폭부에 전달하는 제어부를 포함하는 직교 주파수 분할 다중화 방식 무선 통신 시스템의 자동 이득 조절 장치에 관한 것이다. 본 발명에 따르면, 반복적으로 일정한 시간의 프리앰블 구간과 데이터 구간을 갖는 패킷 전송 방식의 OFDM 시스템에서 많은 샘플 수를 갖는 비교적 긴 길이의 프리앰블을 이용하여 수신되는 신호를 일정한 구간으로 분할하고 분할된 구간에 대해 전력의 이득을 자동으로 조정하여 하나의 프리앰블에서 여러 차례 전력의 이득 조절이 가능하게 되어 빠른 시간 내에 ADC 입력 단에 가장 적합한 신호 전력 레벨을 유지할 수 있다. OFDM, 이득, 최대치 샘플 수, 프리앰블, 분할, 동기 정보