Abstract:
PURPOSE: A time domain equalizer of a VDSL transmission system is provided which effectively reduces the amount of hardware and guarantees compatibility with asymmetric digital subscriber line transmission systems. CONSTITUTION: A time domain equalizer of a VDSL transmission system is constructed in a manner that time domain equalizers by signal bands are serially connected for signal bands obtained by dividing the entire signal band. A time domain equalizer(42) for a high frequency signal band and a time domain equalizer(41) for a low frequency signal band are serially connected. The time domain equalizer for a high frequency signal band and the time domain equalizer for a low frequency signal band obtain the signal bands using an algorithm for reducing a channel impulse response length. The time domain equalizer for a low frequency signal band connects a shift register between tabs to decrease data loss.
Abstract:
PURPOSE: A communication path control device between a digital unit and a radio frequency unit and a method thereof are provided to flexibly transmit and receive data between the digital unit and the radio frequency unit. CONSTITUTION: A first transceiver(600) receives a first signal from a first digital unit. The first signal includes a first identifier indicating a purpose radio frequency unit. A path selecting unit(620) selects a first path of the purpose radio frequency unit based on the first identifier. A second transceiver(640) transmits the first signal to the selected first path. The first identifier indicates one or more purpose antennas. [Reference numerals] (60) Path control unit; (600) First transceiver; (620) Path selecting unit; (640) Second transceiver; (AA,BB,CC) RF unit; (DD) First signal; (EE) Second signal
Abstract:
PURPOSE: A method for simultaneously performing transmission and reception in the same frequency band capable of increasing frequency use efficiency and an apparatus thereof are provided to utilize an electromagnetic field polarization, thereby simultaneously performing transmission and reception in the same frequency band. CONSTITUTION: A second communications device(150) generates a single polarization using a dual polarization transmission antenna. The second communications device transmits a signal to a first communications device(100) (S100). The transmitted signal of the second communications device passing through a radio channel is received by the dual polarization reception antenna of the first communications device. The first communications device performs polarization filtering by tracking the principal axis of the polarization of the signal(S105). The first communications device generates a polarization meeting at completely right angle with the principal axis of a tracked reception polarization using the dual polarization transmission antenna(S110). The second communications device performs adaptive polarization tracking and polarization filtering using the dual polarization filtering reception antenna(S115). [Reference numerals] (100) First communications device; (150) Second communications device; (S100) Single polarization transmission; (S105,S115) Adaptive polarization tracking & polarization filtering; (S110) Polarization transmission perpendicular to the tracked polarization
Abstract:
A method and a device for dividing a receiving symbol signal into bit information are provided to perform a bit division process in a two dimensions simply by dividing the PSK(Phase Shift Keying) modulated symbol into the bit information in consideration of BRGC(Bit Reflected Gray Code) characteristic by using a coordinate rotation method. A rotation angle calculator(150) calculates the rotation angle by using each absolute value about I channel and Q channel symbol signals of the receiving signal which is arranged with the interval of the phase angle on a two dimensional concentric circle. A bit information converter(170) extracts the bit information about each of the I channel or Q channel symbol signals which are rotated by using a rotation angle outputted from the rotation angle calculator. An absolute value converter(120) produces each absolute value about the values of the I channel and Q channel symbol signals of the receiving symbol. A phase angle calculator(130) produces a radian phase angle by using each absolute value about the value of I channel and Q channel outputted from the absolute value converter. A symbol arrangement value calculator(140) produces an arrangement value of the symbols comprising the I channel or Q channel symbol signals by using the radian phase angle outputted from the phase angel calculator.
Abstract:
본 발명은 디지털 통신에서 필수적으로 사용되는 디지털 파형정형필터와 정합필터를 하나의 하드웨어로 구현하는 방법 및 구조에 관한 것이다. 디지털 파형정형필터는 1:N 인터폴레이션 FIR 필터로 구현할 수 있으며, FIR 필터의 각 탭계수 값에는 보통 나이퀴스트(Nyquist) 펄스의 샘플값, 또는 square-root raised-cosine Nyquist 펄스의 샘플값이 사용된다. 그러나 FIR 필터로 파형정형필터를 구현하는 경우 많은 곱셈기가 필요하게 되어 하드웨어의 양을 증가시키는 문제점이 있다. 이를 피하기 위해 일반적으로 파형정형필터의 입력 심볼과 탭계수값을 미리 곱한 결과값을 롬(ROM) 형식의 룩업테이블에 저장해 놓고, 입력 심볼을 롬 주소신호로 하여 결과값을 출력하는 이른바 룩업테이블(look-up) 방식이 사용된다. 그러나 이 방법은 입력되는 심볼의 경우의 수가 적은 경우에 적합하며, 256-QAM 등과 같이 입력 심볼의 경우의 수가 많은 경우에는 롬의 크기가 증가하는 문제점이 있다. 또한, 디지털 통신용 트랜시이버의 수신부에 사용되는 정합필터의 경우 입력 심볼은 더욱 많은 경우의 수를 가지게 되어 룩업테이블 형식으로 구현하기가 불가능하다. 본 발명은 파형정형필터 입력의 경우의 수가 증가하는 경우에도 별다른 하드웨어 증가없이 사용할 수 있고, 또한 수신부 정합필터로도 사용 가능한 다기능 파형정형필터를 제시한다. 본 발명에서는 파형정형필터에 사용되는 나이퀴스트 펄스가 좌우 대칭 형태의 임펄스 응답을 가지는 점과, 임펄스 응답의 중심값과 최외각값의 차이가 매우 큰 점에서 착안하여 FIR 필터의 곱셈기를 1/2로 줄였으며, 또한 덧셈기의 크기도 혁신적으로 줄일 수 있다. 파형정형필터, 정합필터, FIR필터, 곱셈기, 나이퀴스트 펄스