Abstract:
PURPOSE: A method and a device for receiving satellite navigation signals are provided to reduce power consumption and manufacture cost by receiving satellite navigation signals with high quality. CONSTITUTION: A plurality of RF units(205a,205b) receives satellite navigation signals and extracts baseband signals. Signal processing units(215a,215b) treats the baseband signals. A position estimator(220) estimates the position of receiving device through the value outputted from the signal processing unit. A recognition engine reconstructs the RF part and the signal processing unit according to channel environments corresponding to each frequency band.
Abstract:
PURPOSE: By presuming the large-scale fading value of user and controlling the power control mode the control method for minimizing the PAR can minimize PAR. CONSTITUTION: A large-scale fading values of all users are presumed. The number of users in which the large-scale fading value bigger than the standards fading value is counted. The number of subcarrier which users counted use is counted. It is controlled to the power control mode. The large-scale amplitude value of user is presumed. The TX power is adjusted if the large-scale amplitude value is not similar of the reference amplitude value(320). The transmission signal becomes to the TX power adjusted(330).
Abstract:
PURPOSE: A frequency sharing driver and a method thereof of the mobile satellite service using the ground auxiliary device of satellite and satellite are provided to reuse the frequency band of the satellite down link in the satellite ground auxiliary device of the ground. CONSTITUTION: A signal intensity measurement part(205) measures the signal intensity received from the satellite. According to the communications mode decision part(207) is the signal intensity measured at as described above, the communications mode is decided. According to the communications unit(209) is the communications mode, it communicates among the ground auxiliary device of satellite and satellite with one apparatus.
Abstract:
PURPOSE: A method for interaction between ARQ and HARQ of a system with a long shuttling delay time is provided to quickly cope with a transmission error by re-transmitting a packet of a window on standby when an error in which NACk of HARQ is mistaken for ACK occurs. CONSTITUTION: A transmission buffer(210) and a transmit window are influenced by the HARQ feedback information. A buffer on standby(220) and an window on standby are influenced by a status report information packet(230). The buffer on standby detects an error in which NACK is recognized as ACK in HARQ. The buffer on standby re-transmits the packet of the buffer on standby by receiving feedback information concerning the error.
Abstract:
PURPOSE: A mobile satellite communications apparatus and a method thereof are provided, which maximizes frequency use efficiency. CONSTITUTION: If data are received from a mobile terminal, a satellite signal sensing part(421) senses a satellite signal. A subcarrier deciding unit(423) recognizes a subcarrier group used for communications between a mobile terminal and a satellite using a satellite signal. A communications unit(425) communicates with the mobile terminal using subcarrier groups except for the subcarrier group. If the ground auxiliary device locates in the central area of a beam, the subcarrier deciding unit recognizes the first subcarrier group used in communications between the satellite locating in the border of the beam and the mobile terminal.
Abstract:
PURPOSE: A diversity method using an error correction code is provided to combine an error correction code transmitted from a different relay device in a user terminal, thereby obtaining a diversity gain. CONSTITUTION: A diversity method using an error correcting code comprises the following steps. An input bit string which is an encoding target is error-correction encoded to generate a mother code(302). The generated mother code is punched to obtain an error-correction code including systematic information and particle parity information(304). The obtained error-correction code is transmitted(306).
Abstract:
송신기는 수신기로부터 피드백 정보를 수신하고, 피드백 정보를 바탕으로 무선 채널의 채널 환경을 예측한다. 이후 채널 환경에 대응하는 변조 방식에 따라 주파수 다중화 신호를 생성하고, 생성된 주파수 다중화 신호를 전송한다. 이를 통해 인접 반송파 간섭을 제거할 수 있다. 반송파, 간섭, OFDM, 주파수 옵셋, 시공간 코드
Abstract:
An apparatus for tracking polarized waves is provided to track the polarization of transmission signals to a satellite, thereby solving inconsistency of the polarization due to the change in the posture of a satellite or terrestrial terminal and the environment. A polarization tracking apparatus for reception comprises the followings: a feeder(303) which receives vertically and horizontally polarized waves to find out vertical and horizontal polarization factors; a polarization estimator(305) which estimates the deformation of polarization by using the vertical and horizontal polarization factors outputted from the feeder; a polarization controller(307) which controls the amplitude of vertically and horizontally polarized waves and phase information based on the estimated transformation information and signals; and a combiner(311) which combines the vertically and horizontally polarized waves controlled by the controller.
Abstract:
A method and an apparatus for detecting a timing synchronization are provided to obtain a timing synchronization accurately without changing a predefined training symbol. A time synchronization detecting apparatus includes a first sequence generator(10) and a synchronization unit(11). The first sequence generator generates plural first data sequences from a received signal. The synchronization portion correlates the first data sequence with a second data sequence and determines an FFT(Fast Fourier Transform) timing of the received signal by using the correlation result. The first sequence generator includes a mapper, a complex conjugate portion, and a multiplier. The mapper extracts a portion of the received signal and maps the received signal to plural third data sequences. The multiplier multiplies a complex conjugate of the data sequence with other data sequences to output the first data sequence.