Abstract:
PURPOSE: An apparatus and a method for transmitting variable length packet data and a device for receiving data are provided to transmit synchronization information in a satellite communication network environment to which a variable length packet transmission method is applied. CONSTITUTION: A data transmitter(10) inserts synchronization information to transmission data to be transmitted according to a variable length packet transmission method. The data transmitter transmits the transmission data into which the synchronization information is inserted to a data receiver. The data receiver(20) receives the transmission data including synchronization information from the data transmitter. The data receiver restores synchronization data included in the received transmission data. The data receiver synchronizes with the data transmitter according to the restored synchronization data.
Abstract:
PURPOSE: An encapsulating method for transmission data in a digital satellite communication system and a data transmission apparatus are provided to perform bidirectional communication in a satellite communication network. CONSTITUTION: An encapsulating unit(120) partitions a packet data unit to be transmitted to form a baseband data packet of a fixed length into variable length packets. The encapsulating unit adds a header to a variable length packet and a reference time packet. The encapsulating unit encapsulates the added packet. A packet forming unit(130) schedules the encapsulated variable length packet and reference time packet. The packet forming unit forms a baseband data packet.
Abstract:
본 발명은 통신 시스템에서의 채널 상태 검출 장치 및 그 방법에 관한 것으로, 튜너를 통해 입력되는 업 샘플링 신호를 다운 샘플링한 후 다운 샘플링 신호를 이용하여 채널 상태를 검출함으로써, 하드웨어의 복잡성 및 계산량의 증가를 감소시키기 위한, 통신 시스템에서의 채널 상태 검출 장치 및 그 방법을 제공하고자 한다. 이를 위하여, 본 발명은 통신 시스템에서의 채널 상태 검출 장치에 있어서, 튜너(Tunner)를 통해 입력되는 업 샘플링 신호를 필터링하기 위한 정합 필터링 수단; 상기 정합 필터링 수단에서 필터링한 업 샘플링 신호를 다운 샘플링하기 위한 다운 샘플링 수단; 및 상기 다운 샘플링 수단에서 다운 샘플링한 신호를 이용하여 채널 상태를 추정하기 위한 채널 상태 추정 수단을 포함한다. 채널 상태 추정, DVB-S2, 다운 샘플링 신호, 계산량 감소
Abstract:
An apparatus and a method for controlling a gain of a burst signal in an interactive communication system are provided to enable a relay located in a dead zone to adjust a gain of a burst signal through pilot signals detected from a terminal located in a mobile body, thereby preventing deterioration of performance due to signal attenuation inside a tunnel. A transmitting unit(301) produces a burst signal about transmitting data. A pilot generating unit(302) produces a plurality of pilot signals located in the outside of a use frequency band of a mobile terminal. A multiplexing unit(303) multiplexes the burst signal and the pilot signal. The multiplexing unit transmits the multiplexed signals to the relay.
Abstract:
A handover method between heterogeneous network for preventing the disconnection of a session and packet loss is provided to control the handover between wireless network and satellite network by link up/down trigger signal. A mobile node positioned in a first network maintains a second network-connection interface in a sleep state(606). A first network service is supplied by activating a first network-connection interface(607). The second network linkup trigger signal is sensed as the mobile node moves to the second network side. The second network-connection interface is converted into the active state and the handover is performed. The mobile node performing handover receives the second network service through the activated second network-connection interface.
Abstract:
An apparatus and a method for selecting a correlation mode based on a frequency error of a carrier are provided to obtain initial synchronization by selecting the correlation mode according to the corresponding region after calculating a frequency error boundary point between correlation modes. Non-detection probability values are calculated according to a frequency offset normalized in each correlation method(201). A point meeting graphs of non-detection probability values is determined to a frequency error boundary point(202). A correlation mode is selected based on the determined frequency error boundary point(203).
Abstract:
An apparatus and method for multiplexing channel data for supporting variable transmission rate are provided to implement efficiently demodulator and support various transmission rates. The channel data multiplexer(20) comprises a controller(200), an input terminal dual-port block memory(DPBM: Dual Port Block Memory)(201), and an output terminal DPBM(202) and multiplexers(203, 204). The controller controls data read and write of the input terminal and output terminal according to the transmission mode. The controller controls the address processing and clock speed about data output of the first multiplexer. Multi-channel base zone data is input to the input terminal DPBM. The input terminal DPBM stores base zone data of all channels for one time slot. The output terminal DPBM temporarily stores data stored in the input terminal. The multiplexer of the output terminal time-multiplexes data stored in the output terminal and send it to the demodulator(21).
Abstract:
A handover method between heterogeneous networks using a link trigger signal in a mobile router having a multi-interface is provided to prevent the loss of packets and the disconnection of a session regardless of the moving speed of the mobile router which is within a rapid transit railway. While a mobile router positioned in the first network maintains the second network connection interface in the dormant state, it activates the first network connection interface(606). The first network service which the mobile router receives is delivered to a corresponding lower node(607). As the mobile router moves to the second network, if the second network link-up trigger signal is detected, the handover is performed since the second network connection interface is activated(608,609).
Abstract:
An adaptive coding modulation system for an effective signal transmission/reception in a satellite communication system, and a method thereof are provided to maintain synchronization and perform efficient transmission by having a physical layer frame of a predetermined length irrespective of a modulation scheme. An adaptive coding modulation system for an effective signal transmission/reception in a satellite communication system includes a mode adaptive unit(101), a stream adaptive unit(102), a turbo coding unit(103), a mapping unit(104), a physical layer framing unit(105), and a modulation unit(106). The mode adaptive unit receives an input stream, and performs input stream synchronization, a null-packet removal, and a coding for error detection. The stream adaptive unit performs a padding and base-band scramble and forms a base-band frame. The turbo coding unit forms a forward error correction frame by applying a turbo coding to the base-band frame. The mapping unit determines a bit mapping based on a state of a transmission channel. The physical layer framing unit forms a physical layer frame by inserting a header and a pilot symbol into the forward error correction frame. The modulation unit performs a modulation for the physical layer frame to transmit the physical layer frame.
Abstract:
A hierarchical modulation and demodulation method for a digital broadcasting system and an apparatus therefor are provided to enhance transmission efficiency through hierarchical modulation in a currently operated system. An RS(Reed-Solomon) coder(602) encodes the first broadcasting signal. A byte interleaver(605) interleaves the encoded first broadcasting signal. A convolution coder(607) encodes the interleaved first broadcasting signal again. A bit interleaver(609) interleaves the encoded first broadcasting signal. A second coder(617) encodes the second broadcasting signal. A second bit interleaver interleaves the encoded second broadcasting signal. A CDM(Code Division Multiplexing) multiplexer(611) multiplexes the first broadcasting signal and the second broadcasting signal outputted from the first bit interleaver and the second bit interleaver. A hierarchical modulator(613) hierarchically modulate the modulated signal by an 8PSK(8 Phase Shift Keying) type.