Electronics and Telecommunications Research Institute

Deock Gil Oh

Joon Gyu Ryu

Pan Soo Kim

Pansoo Kim

Soo Yeob Jung

Kwang Jae Lim

Yong Ho Lee

Soo Young Kim

Nae-Soo Kim

Hyun Ha Hong

Xavier Giraud

Ji Won Jung

Man Kyu Park

Mankyu Park

Jonggyu Oh

Jae Hoon Kim

Min Hyuk Kim

Dae Ig Chang

Sooyoung Kim

Byung Su Kang

In Ki Lee

Min Su Shin

Jae Moung Kim

Young Wan Kim

Myung Sup Kim

Eun A Choi

Minglu Jin

Serk Soon Im

Jin Suk Seong

Do Huy Wang

Chul Hen Seo

Disclosed is a communication method of a satellite and a ground station and apparatuses performing the same. The communication method includes transmitting a plurality of frames to a satellite based on a beam hopping time plan (BHTP) of the satellite and a ground station and synchronizing the BHTP based on an index of a frame received through a beam switching window (BSW) allocated to the ground station among the plurality of frames, and an identification value indicating at least one sub-frame included in the frame.

Communication method of satellite and ground station, and apparatuses performing the same

Disclosed is a communication method performed between a satellite and a ground station and apparatuses performing the communication method. The communication method includes transmitting a plurality of frames based on a beam allocation time schedule (BATS) between a satellite and a ground station, and synchronizing the BATS based on a reception time and a detection time of one or more frames among the plurality of frames to be received through a beam open window (BOW) allocated to the ground station.

Communication method and apparatuses performing the same

Disclosed is a demodulation method to be used by an apparatus receiving a data packet transmitted in wired and wireless communications to recover data from a received signal. The apparatus receiving the data packet may recover or synchronize a symbol timing that is used to recover the data, and a demodulator included in the apparatus receiving the data packet may determine the symbol timing through different methods based on a length of a burst included in the data packet.

Modem performing modulation or demodulation based on length of burst in data packet, and method performed by the modem

A signal processing method, and a transmitter and a receiver are disclosed. The signal processing method may include converting a transmission signal to a non-periodic sequence type transmission signal using periodic sequences and transmitting the non-periodic sequence type transmission signal to the receiver, in which the receiver may detect a burst from the received non-periodic sequence type transmission signal.

Signal processing method and transmitter and receiver

Disclosed is a star network/mesh network accessing method and apparatus of a terminal in a satellite communication system, the method including receiving time slot resources from a central station and operating in a time division multiple access (TDMA) start network communication mode between the central station and a terminal, transferring, to the central station, a TDMA mesh network connection request message for a destination terminal, receiving traffic burst time plan (TBTP) information corresponding to the TDMA mesh network connection request message from the central station and operating in a TDMA mesh network communication mode between terminals, and switching from the TDMA mesh network communication mode between the terminals to a single channel per carrier (SCPC) mesh network communication mode between the terminals when Voice over Internet Protocol (VoIP) traffic is greater than a threshold.

Apparatus and method for accessing star network/mesh network of time division multiple access (TDMA)/single channel per carrier (SCPC) integrated satellite communication

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 is a network synchronization apparatus and method of a time division multiple access (TDMA)-based mesh network satellite communication system, the network synchronization method of a terminal in a satellite communication system including receiving timing error information from a central station, generating a mesh superframe start time (SST') by reversing a sign of the timing error information, and receiving traffic information transmitted by a transmission terminal using the mesh SST&#x2032;.

Network synchronization apparatus and method of time division multiple access (TDMA)-based mesh network satellite communication system

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

Disclosed are a signal receiving apparatus based on FTN and a signal decoding method thereof, and the apparatus includes: an equalizer calculating, when a signal sampled by Fast to Nyquist (FTN) is received on a communication channel, a posterior probability of information bits and calculating a log likelihood ratio by using the calculated posterior probability; a deinterleaver deinterleaving bit data output from the equalizer; a decoder correcting of signal interference of the data bits deinterleaved by the deinterleaver by using the LLR and decoding the corrected signal interference; and an interleaver interleaving data output from the decoder to provide the interleaved data to the equalizer.

Signal receiving apparatus based on faster than nyquist and signal decoding method thereof

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

A maximum a posteriori (MAP) decoding apparatus and method are provided, which select a path having a maximum value without calculating all path metrics by generating metric difference vectors based on generated tables, calculating metrics of a path formed through a combination of a state and a branch each having a maximum metric, and calculating an index and a metric of a current state to which a calculation value is to be applied based on a result of comparing a state metric difference vector and a branch metric difference vector.

Apparatus and method for decoding maximum a posteriori

Provided is a method of detecting a packet error of a return link performed in a satellite communication apparatus receiving a packet through the return link. The method includes generating a first return link packet combination by assembling at least one fragmented packet received through the return link, and determining an error of the packet using at least one piece of information among fragmentation information on at least one second return link packet received after the first return link packet combination is generated, whether or not the first return link packet combination is complete, and packet process state information. Accordingly, it is possible to minimize packet loss caused by a reassembly error of a received packet.

Method of detecting packet error of return link performed in satellite communication apparatus

Provided is a method of identifying a transmission control protocol (TCP) packet loss, including transmitting at least one TCP data packet to a TCP receiver, estimating wireless channel status information using the TCP receiver by interaction between a TCP layer and a physical layer, and receiving an acknowledgement (ACK) packet including the estimated wireless channel status information from the TCP receiver.

Apparatus and method for identifying transmission control protocol (TCP) packet loss

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

An adaptive coding and modulation (ACM) apparatus and method for a forward link in satellite communication is provided. The ACM apparatus may include a receiving unit to receive a signal-to-noise ratio (SNR) of a received signal, a determination unit to determine whether the SNR of the received signal is less than or equal to a threshold value, and a processing unit to execute a channel prediction algorithm when the SNR of the received signal is determined to be less than or equal to the threshold value.

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Daejeon, South Korea

Deock Gil Oh