Abstract:
A hierarchical modulation apparatus for improving a transmission performance of an OFDM transmission system using the insertion and the specific arrangement pattern of a pilot, and a method thereof are provided to improve a receiving performance by additionally transmitting a pilot signal to an enhancement layer signal. A hierarchical modulation apparatus for improving a transmission performance of an OFDM transmission system using the insertion and the specific arrangement pattern of a pilot includes a first channel coding unit(200), a second channel coding unit(210), a pilot insertion unit(220), and a layer modulation unit(240). The first channel coding unit encodes a base layer signal column. The second channel coding unit encodes an enhancement signal column. The pilot insertion unit inserts a pilot into the enhancement signal column. The pilot has the correlation with the base layer signal column corresponding to the same sub carrier with the enhancement layer signal column which is encoded in the second channel coding unit. The layer modulation unit modulates and combines each of the signal columns outputted from the first channel coding unit and the pilot insertion unit.
Abstract:
An apparatus and a method for applying amplitude-differential phase shift keying are provided to maintain compatibility of main transmission data to a pre-differential phase shift keying and to improve a transmitting speed by modulating the main transmission data with a differential phase shift keying manner and modulating additional transmission data with the other differential phase shift keying manner. An apparatus and a method for applying amplitude-differential phase shift keying includes a first modulating unit modulating a first data sequence with a differential phase shift keying manner. A second modulating unit modulates a second data sequence with an amplitude shift and inserts a pilot signal to the amplitude shift modulated signal. A multiplier outputs after multiplying output data of first and second modulating units. The pilot signal is periodically or non-periodically inserted at a position of a sub-carrier of the amplitude shift modulated signal. A first demodulating unit(31) receives an amplitude-differential phase shift keying modulated signal and demodulates the received signal with the differential phase shift keying. A second demodulating unit(324) extracts the pilot signal from the received signal.
Abstract:
Distributed repeaters and a repeating method thereof are provided to suppress a noise due to a transmission path between a main transmitter and the repeater and a multipath signal by using a high performance equalizer. An RF(Radio Frequency) receiver(402) receives an RF broadcasting signal from a main transmitter through a reception antenna(401). An IF down-converter(403) converts the RF broadcasting signal into an IF(Intermediate Frequency) signal. A demodulator(404) converts the IF signal from the IF down-converter to a baseband signal. An equalizer(405) equalizes the baseband signal and compensates for a distortion due to a transmission channel. An ID signal generating/inserting unit(406) generates an ID signal with a high correlation property and inserts the ID signal to the baseband signal. A modulator(407) converts the baseband signal into the IF signal. An RF up-converter(408) converts the baseband signal into an RF broadcasting signal. A high power amplifier(409) amplifies the RF broadcasting signal and transmits the amplified result using transmission antennas.
Abstract:
A method and an apparatus for hierarchical modulation/demodulation in an OFDM(Orthogonal Frequency Division Multiplexing) system are provided to perform an in-phase demodulation by using a pilot which is transferred to a second layer. A hierarchical modulation apparatus in an OFDM system includes first and second encoders(110,120), a pilot insertion unit(130), and a hierarchical modulation unit(140). The first encoder encodes a first layer signal stream, which is a basic layer signal. The second encoder encodes a second layer signal stream which is an enhancement layer signal. The pilot insertion portion inserts a pilot signal for estimating a channel coefficient to an encoded second layer signal stream. The hierarchical modulation portion modulates the second layer signal stream, to which the pilot signal is inserted, and the encoded first layer signal stream, and combines the encoded signals with each other.
Abstract:
A partial correlation matched filter for TxID(Transmitter Identification) using an interference cancelled spreading code and a filtering method thereof are provided to deduce correlation characteristics within a short time by minimizing chip correlation operations of a correlation calculation part of a ZCD(Zero Correlation Duration) code having a long period used for watermarking in a receiving terminal, and reduce hardware volume and power consumption. A first shift register(22) shifts a transmitted spreading code. A ZCD code controller(21) outputs a switch signal in order to remove zero components among the spreading codes outputted from the first shift register. A component removing unit removes the zero components from the output of the first shift register through the switch signal of the ZCD code controller. A partial correlator(23) calculates a correlation value with a reference code after receiving the spreading code where the zero components are removed by the zero component removing unit.
Abstract:
지상파 DMB에 있어서, 전송 장치는 임의의 서비스에 대하여 생성된 복수의 서비스 스트림을 복수의 앙상블로 다중화한다. 이때, 복수의 앙상블 각각에 대한 전송 프레임 각각의 타임 스탬프 필드에 동일한 송출 시간 데이터를 구성한다. 이와 같이 하면, 복수의 송신 장치가 동일한 서비스에 대한 서비스 스트림을 포함하는 복수의 전송 프레임을 동일한 시간에 송출하여, 수신 장치가 사실상 동일한 시각에 복수의 전송 프레임을 수신할 수 있다. 지상파 DMB, 앙상블, ETI, TIST, 타임스탬프, 프레임 다중화
Abstract:
본 발명은, 디지털 방송을 위한 전송 시스템에서 전송 프레임의 앞부분에 프레임 헤더 정보를 추가하여 시간적으로 서로 다른 전송 프레임에 서로 다른 전송모드, 변조 레벨, 계층 변조, 에러 정정 부호 등을 정할 수 있는 디지털 방송 신호의 전송 방법, 전송 장치, 수신 방법, 수신 장치 및 이의 전송 프레임 구조에 관한 것이다. 전송 프레임 구조는, 전송 프레임의 다중화 정보를 포함하는 프레임 헤더; 및 상기 전송 프레임이 제공하는 서비스에 대한 데이터 정보를 포함하는 프레임 바디를 포함한다. 또한, 상기 프레임 헤더는, 상기 전송 프레임의 시작 위치를 추출하기 위한 동기 신호 정보를 포함하는 프레임 동기신호부; 및 상기 전송 프레임이 포함하고 있는 데이터의 다중화 정보―상기 전송 프레임이 포함하고 있는 데이터의 전송 모드, 변조 레벨, 계층 변조, 에러 정정 부호의 정보―를 포함하는 프레임 정보부를 포함할 수 있다. 디지털 방송, 전송 프레임, 전송 모드