Electronics and Telecommunications Research Institute

Pan Soo Kim

Deock Gil Oh

Joon Gyu Ryu

Dae Ig Chang

Soo Yeob Jung

Dong Hyun Jung

Ho Jin Lee

Gyeong Rae Im

Yong Ho Lee

Tae Hoon Kim

Jung Bin Kim

Xavier Giraud

Min Su Shin

Jae Hee Han

An operation method of an IoT terminal performing communications with a satellite may comprise: receiving a first signal from the satellite; determining a number of symbols constituting a preamble based on the first signal; generating a first frame including a preamble generated according to the determined number of symbols, and transmitting the generated first frame to the satellite; and generating a second frame including a preamble generated according to the determined number of symbols when a response signal to the first frame is received from the satellite, and transmitting the generated second frame to the satellite.

Satellite communication method and apparatus for internet of things communication

A timing control method performed by a terminal included in a communication network may include: configuring an initial timing reference based on time information obtained from the communication network; receiving a first downlink (DL) signal from a base station; based on the initial timing reference and the first DL signal, obtaining first transmission time information that is information on a timing when the first DL signal is transmitted by the base station and first reception time information that is information on a timing when the first DL signal is received by the terminal; determining a first timing advance (TA) value based on comparison between the first reception time information and the first transmission time information; and adjusting an uplink (UL) transmission timing for the base station based on the first TA value.

Method and apparatus for timing control in wireless communication system

A method for receiving a wireless signal, performed by a first communication node, may comprise: storing a wireless signal received by the first communication node as samples in a buffer; performing partial correlation operations on the stored samples by a plurality of partial correlators; performing a first FFT operation on results of the partial correlation operations; performing a cumulative product operation on results of the first FFT operation; performing a second FFT operation based on a result of the cumulative product operation; and performing synchronization estimation based on the results of the first FFT operation and a result of the second FFT operation.

Method and apparatus for receiving wireless signal in wireless communication system

Provided is a data transmitting and receiving apparatus that may process a signal to be transmitted using a faster-than-Nyquist (FTN) method. The data transmitting and receiving apparatus may perform low-density parity-check (LDPC) encoding on data to be transmitted using a first matrix having a first degree based on a preset reference and a second matrix having a single diagonal matrix structure, independently perform interleaving and symbol mapping on each of an information bit and a parity bit of the data, accelerate an output signal by a transmission rate based on the FTN method, and transmit the data.

Data transmitting and receiving apparatus having improved low-density parity-check (LDPC) encoding, decoding and transmission rate

Disclosed are a communication apparatus and a communication method capable of improving transmitting/receiving frequency efficiency of a satellite signal per bandwidth or spectral efficiency (S.E) per bandwidth by removing and improving a distortion or inter-symbol interference for applying a minimum-mean square error (MMSE) equalizer required to detect a frame synchronization and a modulation code rate in a satellite service for satellite broadcasting or communication under the variable coding and modulation (VCM) or adaptive coding and modulation (ACM) environment.

Communication apparatus and method for high efficiency satellite service

An apparatus and method for transmitting, through multiplexing a data frame that generates at least one super frame including at least one slice configured in a unit of a plurality of PLframes, generates a multiplexing super frame by rotating the at least one super frame by a predetermined phase value, and transmits the at least one super frame is provided.

Device and method for transmitting multiplexed data frame

Provided is a system and method for synchronization between digital-to-analog converters (DAC) for high speed signal processing. A synchronization method of a multi-DAC apparatus may include: inputting a clock to a multiplexer (MUX) DAC; dividing the clock into a first clock and a second clock; transferring a phase difference between the first clock and the second clock to a D flip-flop; and synchronizing the first clock and the second clock by processing the phase difference.

System and method for synchronization between digital-to-analog converters (DACs) for high speed signal processing

Provided are a modulation method and a demodulation method for satellite communication using a widespread signal-to-noise ratio (SNR), the method including: adding a dummy frame to a broadcasting/communication signal frame for signal transmission of a digital video broadcasting-satellite second generation (DVB-S2) modulator; verifying a spreading factor; adding the same physical layer header to the broadcasting/communication signal frame to which the dummy frame is added, repeatedly the number of times corresponding to the verified spreading factor; and repeating the same data, for example, PL frame data as the physical layer header.

Modulation and demodulation method for satellite communication using widespread signal-to-noise ratio (SNR)

Provided is a digital video broadcasting-satellite-second generation (DVB-S2) based transmission and reception apparatus and method operable in circumstances of a low signal to noise ratio (SNR), the DVB-S2 based transmission and reception apparatus including a DVB-S2 based transmitter, a mapping unit to determine bit mapping based on at least one of a state of a transmission channel and an area to be applied, and a physical layer frame (PLframe) replica processing unit to repeat a PLframe in which a physical layer header (PLheader) corresponding to a spreading factor (SF) is inserted.

Digital video broadcasting&#x2014;satellite&#x2014;second generation (DVB-S2) based transmission and reception apparatus and method operable in circumstances of low signal to noise ratio (SNR)

Provided is an apparatus and method for iteratively detecting and decoding a received signal in a wireless communication system. An apparatus for iterative detection and decoding (IDD) in a wireless communication system may determine a predetermined group to be updated in a first soft decision sequence, may transmit detection control information of the determined group, and may generate a second soft decision sequence based on a detection operation result of a predetermined received signal portion that is extracted based on the detection control information.

Apparatus and method for iterative detection and decoding in wireless communication system

Provided are a satellite VSAT apparatus and a control method thereof. The satellite VSAT apparatus according to an exemplary embodiment of the present invention can switch a modulation type of a signal to be transmitted from an indoor unit (IDU) to the outdoor unit to a linear or non-linear type in a case in which outputting of a transmitted signal is not controlled to an outdoor unit due to limitations, that is, there is no function such as an automatic signal level control in a block up-converter (BUC), a case in which transmission output limitation is large due to a lot of interference requirements for an adjacent channel, a case in which the number of adjacent channels (carriers) is large, or a case in which adjacent channel interference is large due to a frequency in a satellite multi-beam environment and polarization reuse, in a satellite VSAT apparatus system which aims at a low-priced user terminal.

Dual mode satellite very small aperture terminal apparatus and controlling method thereof

The present invention separates inputted triple play IP data into Internet and TV data and voice (VoIP) data, encodes the Internet and TV data permitting a long delay time according to the existing DVB-S2 standard, and encodes the voice data permitting only a short delay time according to a DVB-RCS+M standard based 4K mode. Each encoded data is subjected to the orthogonal modulation and the orthogonally modulated voice data is subjected to a direct sequence spectrum spread according to a spreading factor. The spread spectrum signal is multiplexed in a SCPC frequency division multiple access (FDMA) scheme so as to overlap with frequencies allocated to each user.

Terminal transmission apparatus for providing multimedia service via satellite communication link and method for providing multimedia service using the same

A Second Generation Digital Video Broadcasting via Satellite (DVB-S2) system is provided. More particularly, a method and apparatus for maintaining synchronization of a signal by changing an Adaptive Coding and Modulation (ACM) method that is used for a conventional DVB-S2 system are provided. In the apparatus and method, an FEC frame of a variable length is formed by turbo encoding rather than Bose-Chaudhuri-Hocquenghem (BCH) and Low Density Parity Check (LDPC) encoding, and a Physical Layer (PL) frame of a specific length is formed regardless of a modulation method, so that a satellite terminal receives a signal transmitted at a specific length regardless of a modulation method or a coding rate to easily maintain synchronization without interruption and efficiently transmit the signal.

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Daejeon, South Korea

Pan Soo Kim