Abstract:
1. 청구범위에 기재된 발명이 속하는 기술분야 본 발명은 양방향 위성통신 시스템에서의 데이터 전송률 제어 방법에 관한 것임. 2. 발명이 해결하려고 하는 기술적 과제 본 발명은 양방향 위성통신 시스템에서 이동 단말의 음영지역(NLOS) 통과시에 음영지역(NLOS)에 의한 통신회선의 낭비를 줄이기 위한 데이터 전송률 제어 방법을 제공하고자 함. 3. 발명의 해결 방법의 요지 본 발명은, 위성통신 시스템에서의 데이터 전송률 제어 방법에 있어서, 단말이 음영지역(NLOS)에 진입하여 귀환할 때까지의 정밀 주파수 동기(fine sync) 상태를 유지하는 적어도 하나의 통계적인 시간길이(적어도 하나의 임계치)를 설정하는 임계치 설정단계; 중심국이 제어정보 송신 필드(SAC 필드)의 소실 유무로 상기 단말의 음영지역(NLOS) 진입을 감지하여, 고정자원할당(CRA) 방식으로 할당된 자원을 재조정하는 자원재조정단계; 제1 임계치 범위내에 상기 단말이 음영지역(NLOS)으로부터 귀환하면, fine sync 상태를 유지시켜, 추가할당을 통해 전송지연을 보상하는 자원보상단계; 및 상기 제1 임계치 범위내에 상기 단말이 음영지역(NLOS)으로부터 귀환하지 않으면, CRA 방식으로 할당된 자원을 모두 회수하는 자원회수단계를 포함함. 4. 발명의 중요한 용도 본 발명은 양방향 위성통신 시스템 등에 이용됨.
Abstract:
본 발명은 위성망과 지상망의 연동을 위한 망 연동 장치에 관한 것으로, 지상망을 백업하고 위성망을 통해 지상 ATM 데이터 뿐만 아니라 비디오 데이터, 인터넷 데이터까지 고속으로 광대역 멀티미디어 서비스를 제공할 수 있는 지상망과의 접속 및 위성망과 연동 기능을 수행하는, 위성망과 지상망의 연동을 위한 망 연동 장치를 제공하며, 지상 비동기전송모드(ATM) 망과 연결되어 소정의 속도로 비동기전송모드(ATM) 셀 데이터를 출력하기 위한 비동기전송모드 처리수단; 엠펙(MPEG)-2 트랜스포트 스트림의 비디오 신호를 AAL5(ATM Adaptation Layer 5) 방식에 의하여 비동기전송모드(ATM) 셀 데이터로 생성하여 출력하기 위한 엠펙(MPEG) 처리수단; 패스트 이더넷 프레임 데이터를 AAL5 방식에 의하여 비동기전송모드(ATM) 셀 데이터로 생성하여 출력하기 위한 인터넷 처리수단; 및 상기 비동기전송모드 처리수단, 상기 엠펙(MPEG) 처리수단, 상기 인터넷 처리수단과 비동기전송모드 셀 데이터를 교환하고, 위성모뎀과 소정의 속도로 비동기전송모드(ATM) 셀 데이터를 교환하기 위한 비동기전송모드 데이터 처리수단을 포함하고, 통신 시스템 등에 이용됨.
Abstract:
Disclosed is a frequency hopping system for converting frequencies of signals into RF (radio frequency) signals, which comprises: a frequency hopper (200) for outputting signals with temporarily varied frequencies according to a predetermined pattern; a fixed PLL (phase locked loop) unit (500) for outputting frequency-fixed signals; a mixer (400) for mixing the output signals of the frequency hopper and the fixed PLL unit, and outputting frequency-hopped local signals; and a modulator (100) for receiving I and Q (in-phase and quadrature-phase) signals from a baseband device, synthesizing the I and Q signals with the frequency-hopped local signals, combining the two synthesized signals, and outputting RF signals.
Abstract:
PURPOSE: A pragmatic TCM(Trellis Code Modulation) decoder using coset mapping and a decoding method thereof are provided to perform a 3-bit soft decision without a sector phase quantizer by using a mapping method on a constellation. CONSTITUTION: A pragmatic TCM decoder using coset mapping includes a coset mapper, a first decoder, and a second decoder. The coset mapper(210) is used for obtaining a phase of a received decoding signal by using coordinates of an I-axis and a Q-axis on a constellation. In additional the coset mapper is used for obtaining information to decode coded data by using the obtained phase and the coordinates. The first decoder(220) is used for decoding the coded data by using the information obtained from the coset mapper. The second decoder(234) is used for obtaining non-coded data by using the coordinates and the decoded data.
Abstract:
PURPOSE: A method for transmitting an adaptive packet in a cellular phone mobile communication system by using a multi beam satellite is provided to select a sector/beam requesting a minimal power, and to select a wireless resource of a transmission frame, then to assign a minimal power requested to satisfy packet reception quality by using a transmission path gain estimated for each user, thereby minimizing interference in other packet transmissions. CONSTITUTION: A system updates an active beam set for each user(501), and updates transmission path gains for each user based on an RSSI of a reported pilot signal(502). The system sets priorities for packets included in headers of transmission queues of each service(503). The system decides whether packets are to be assigned(504). If so, the system assigns packets for a reserved assignment service by a reserved assignment system(506), and assigns packets for a sharing assignment service by a sharing assignment system(510). If the packet assignment is successful, the system removes packets corresponding to an assigned transmission(509). If the packets fail in the assignment by the sharing assignment system, the system does not attempt assigning the packets(512).
Abstract:
PURPOSE: A wireless terminal capable of charging by using non-contact magnetic induction and transceiving a signal and a wireless terminal charging device having a hands-free function are provided to enable the charging without inserting a connector by using a non-contact near magnetic induction method, and to transceive signals, thereby simultaneously performing a charging function and a hands-free function. CONSTITUTION: A wireless terminal(610) comprises as follows. A power receiving device(611) transmits a current to a battery(612). The battery(612) charges the current, and supplies power to each unit. A wireless terminal body(620) performs wireless communication. A controller(622) controls a charging caused by an inducted current, a charging of transmitting a voice signal, and the voice signal. A switching unit(632) transmits the voice signal to a built-in voice input/output unit(631) or a transceiving signal processor(633), or transmits a voice signal received from the input/output unit(631) or the processor(633) to the terminal body(620). The built-in voice input/output unit(631) inputs a voice signal from a microphone or outputs the voice signal. The transceiving signal processor(633) transmits the voice signal of the body(620) to a wireless terminal charging device, and transmits a voice signal received from the charging device to the switching unit(632).
Abstract:
PURPOSE: A method and an apparatus for evaluating a DC offset in a digital quadrature demodulator are provided to improve capacity of a demodulator by removing a direct current component. CONSTITUTION: A hard limiter(91) is used for limiting an amplitude of an output signal of an A/D converter(40). A filter(+Mean)(92) is used for receiving only positive signals of A/D output signals and calculating a mean value for absolute values of the positive signals. A filter(-Mean)(93) is used for receiving only negative signals of the A/D output signals and calculating a mean value for absolute values of the negative signals. An adder adds an output of the filter(+Mean)(92) to an output of the filter(-Mean)(93). A loop filter(95) is used for filtering an output of the adder and outputting an offset control signal to the A/D converter(40).
Abstract:
PURPOSE: An active phased array antenna system for a mobile satellite communication and a beam control method for satellite tracking are provided to track a satellite at a high speed, achieve a high gain and employ a wider electronic tracking range. CONSTITUTION: A receiving channel signal beam forming unit passes a plurality of channels through a phase shifter and combines signals. A tracking signal beam forming unit makes plural channel receiving signals into four groups and passes the same through the phase shifter to combine the signals. A tracking signal detecting unit detects size of the signal formed by the tracking signal beam forming unit. A phase tracking processing unit calculates a phase pointing error relative to the beams of the tracking signals based on signal strength detected by the tacking signal detecting unit and calculates a phase pointing error with respect to the receiving channel signal beams and the transmission signal beams. A tracking beam control unit calculates a phase variation value from the satellite pointing error of the tracking signal beams and controls a phase value of the phase shifter inside the receiving active phased array antenna. A receiving channel beam control unit calculates a phase variation value from the satellite pointing error of the receiving channel signal beams and controls the phase value of the phase shifter inside the receiving channel signal beam forming unit. A transmitting beam control unit calculates a phase variation from the satellite pointing error of the transmission signal beams and controls the phase value of the phase shifter inside the transmitting active phased array antenna.