Electronics and Telecommunications Research Institute

Kumoh National Institute of Technology

Ho-Jin Lee

Deock-Gil Oh

Yun-Jeong Song

Ki-Dong Lee

Pansoo Kim

Do-Seob Ahn

In-Bok Yom

Dae-Ig Chang

Pan-Soo Kim

Young-Wan Kim

Nae-Soo Kim

Yong-Hoon Cho

So-Hyeun Yun

Sooyoung Kim

Byoung-Hak Kim

Woo-Seok Yang

Jin-Young Kim

Soon-Ik Jeon

Jae-sung Park

Jun Young Heo

Kwang-Jae Lim

Seong-Pal Lee

Soo-Young Kim

Seung-Joon Lee

Changsoo Kwak

Jae-hoon Kim

In-Ki Lee

Jong-Won Eun

Hoon Jeong

Bon-Jun Ku

Kunseok Kang

Cheol-Oh Jeong

Jeom-Hun Lee

Hyun-Ha Hong

Namshik Kim

In-Kwon Ju

Nam-Kyung Lee

Gwang-Ja Jin

Joon-Gyu Ryu

Tae-Chul Hong

Ki-seop Han

Min-Su Shin

Yong-Deuk Lee

Ho-Kyom Kim

Moon-Hee You

PanSoo Kim

Dae-Ig Jang

Joong-Gon Ryoo

Bongseop Song

Hyuncheol Park

Sun-heul Ryoo

Minsu Shin

Donghwan Shin

Yun-Jeoug Song

Kun-Nyeong Chang

Young-Sun Lim

Ji-Whan Ko

Yeonsu Kang

Disclosed is a phase error estimating an apparatus and a method which provides improved convergence speed and tracking speed even in mobile channel environment by variably applying the step size for phase error estimation according to channel status. The apparatus for estimating a phase error includes: a posterior probability (APP) average calculating unit for calculating an APP average value from a soft decision result of a currently received symbol; a step size determining unit for determining a step size variably according to channel status; and a phase error estimating unit for estimating a phase error of the currently received symbol from a phase error of a previously received symbol and the APP average value by using the variably determined step size.

Apparatus and method for estimating phase error based on variable step size

A system for controlling temperature of an antenna module including a heat generating module, and a radome and an underbody cover that enclose the heat generating module. The system includes: a heat collecting unit mounted on inner surface of the antenna module; a heat discharging unit mounted on outer surface of the antenna module; and a heat transfer unit for transferring heat from the heat collecting unit to the heat discharging unit.

System for controlling temperature of antenna module

A power controlled adaptive modulation and coding (AMC) scheme in a satellite communications system includes: calculating, by a user terminal, a received signal-to-noise ratio (SNR) through a packet received from a base station; removing a power control level applied to a packet received before the received packet from the calculated received SNR, and deciding the value obtained by decreasing the calculated received SNR by the power control level; deciding an AMC mode based on the decided received SNR; determining whether power control is required, and deciding a required power control magnitude depending on a channel state positioned in the AMC mode range; transmitting the decided AMC mode and the decided power control information to the base station through channel quality indicator (CQI) feedback; and applying the AMC mode based on information received, and increasing a power by a power control magnitude decided from the received information.

Power controlled adaptive modulation and coding scheme in satellite communications system

There is provided a frequency Selective Surface (FSS) structure for multi frequency bands configured with unit cells, each including a loop unit, arranged at regular intervals, wherein each unit cell includes: a dielectric layer; and the loop unit having a fixed width and formed on the dielectric layer, wherein the loop unit includes a first loop and a second loop formed inside the first loop with a predetermined space away from the first loop, each of the first loop and the second loop being formed sinuously in at least one portion.

Frequency selective surface structure for multi frequency bands

Provided is a device for tracking polarizations. A receiving polarization tracking device includes a feeder for finding vertical and horizontal vector components by receiving vertical and horizontal polarizations, a polarization estimator for estimating distortion of polarizations using the vertical and horizontal vector components outputted from the feeder, a polarization controller for controlling amplitudes and phases of vertical and horizontal polarizations based on information about the estimated distortion from the polarization estimator and an output signal from the receiving polarization tracking device, and a combiner for combining the vertical and horizontal polarizations controlled from the polarization controller.

Device for tracking polarization

An apparatus and method for acquiring reliable frame synchronization performance and frequency synchronization simultaneously in a communication system includes a differential correlator outputting a result value obtained by performing a differential operation based on an input signal having symbol timing synchronization and a value pre-defined with a sender sending the input signal, a frequency error calculator compensating for a frequency error based on the result value of the differential correlator and a frequency compensation control signal, and a frame synchronization determiner outputting the frequency compensation control signal if the result value of the differential correlator is greater than a threshold set having at least one value. By introducing a correlation scheme, i.e. Differential Generalized Post Detection Integration (DGPDI), in which differential information corresponding to a half of a symbol duration length is used within a duration from a frame start symbol to a UW symbol duration in a TDM/TDMA transmission structure in which a low SNR and a high frequency error must be considered, a more reliable frame synchronization estimation value can be acquired in comparison to a conventional frame synchronization scheme in which differential information between single neighbor symbols is used.

Apparatus and method for acquiring frame synchronization and frequency synchronization simultaneously in communication system

Provided is a method for handover between heterogeneous networks using a link trigger signal in a multi-interface mobile router. The method includes: maintaining a state of a second network access interface in a sleep state, activating a first network access interface, receiving and transmitting the first network service to a subordinate node in the mobile router located in a first network; when the mobile router senses a second network link-up trigger signal while moving to the second network, changing the state of the second network access interface into an active state and performing handover; and receiving a second network service through the activated second network access interface in the mobile router performing the handover and transmitting the second network service to the subordinate node.

Method for handover between heterogeneous networks using link trigger signal in multi-interface mobile router

This research discloses an ultra wideband system-on-package (SoP). The SoP includes a package body; a first integrated circuit mounted on the package body; a first signal transmission unit connected to the first integrated circuit; a signal via connected to the first signal transmission unit and including a slab line and a trough line; and a second signal transmission unit connected to the signal via. The technology of the present research can transmit ultra broadband signals by minimizing discontinuity of signals appearing during vertical transition that occurs in the course of a signal transmission to/from an external circuit, and a fabrication method thereof.

Ultra wideband system-on-package

Provided are an apparatus for estimating a phase error and a phase error correcting system using the phase error estimating apparatus. The apparatus includes: a probability value estimating unit for estimating a negative log probability value for each transmission symbol by transforming a soft output information transferred from the outside to a log A posterior probability ratio (LAPPR) value; an APP value calculating unit for calculating a posterior probability (APP) value by applying a negative exponential function to the transmission symbol; an average value deciding unit for deciding an average value for each transmission symbol using the probability information entirely, partially, or selectively according to a probability information type; and a symbol phase estimating unit for estimating a phase of a symbol based on the decided average value.

Apparatus for estimating phase error and phase error correction system using the same

Provided are repetition apparatus and method for repeatedly transmitting and receiving a data packet using different puncturing patterns to overcome signal attenuation and fading in a high speed mobile environment by repeatedly transmitting the duplicated information bit sequences with parity bits having a different puncturing pattern after channel-encoding the duplicated information bit. The repetition apparatus for repeatedly transmitting a data packet, includes a dual data generator for generating duplicated information bit sequences identical to each of information bit sequences to transmit, a channel encoder for dividing each of the duplicated information bit sequences into a plurality of information bits, and generating coded data packets alternately having a plurality of parity bits according to different puncturing patterns for each of the divided information bits, and a transmitter for transmitting the generated coded data packets sequentially.

Repetition apparatus and method for repeatedly transmitting and receiving data packet using different puncturing patterns

There are provided an apparatus and method for traffic performance improvement and traffic security in an interactive satellite communication system. The method for traffic performance improvement of an interactive satellite communication system includes the steps of: a) storing an Internet protocol (IP) packet that is received from a user terminal connected to a satellite mobile terminal of the interactive satellite communication system and is to be transmitted to a central station through a satellite; b) transmitting acknowledgement for the stored IP packet to the user terminal by acting for the central station, before the stored IP packet is transmitted to the central station; and c) transmitting the stored IP packet through the satellite to the central station, and retransmitting an unacknowledged IP packet according to a retransmission request of the central station.

Apparatus and method for traffic performance improvement and traffic security in interactive satellite communication system

An apparatus and method for phase recovery in a wireless communication system employs independently decodable component codes. The apparatus includes a decoding unit for decoding the input signal to thereby output the decoding value; an estimation unit for estimating phase errors of the received signal by estimating phase errors of the each component codeword in the received signal to thereby generate phase error estimation values; and a correction unit for correcting the phase of received signal using the phase error estimation values to thereby generate the phase corrected signal in an effective manner.

Apparatus and method for phase recovery using independently decodable component codes of channel code in wireless communication system

Provided are a forward link rain attenuation compensating apparatus using an adaptive transmission scheme in an interactive satellite communication system and a method thereof. The apparatus separates the mobile stations into clear-sky mobile stations and mobile stations in the state of rain attenuation and makes the clear-sky mobile stations receive data having a high data transmission efficiency at a high-speed while making the rain attenuation mobile stations receive the data continuously although the data transmit rate is low by making each of the two kinds of mobile stations receive data frames of a different transmission method, and provides a method therefor. The apparatus includes: a resource manager, a transmitting data format converter, a forward modulator, a backward demodulator, a receiving data format converter.

Apparatus and method for compensating forward link rain attenuation based on adaptive transmission scheme for interactive satellite transmission system

Provided are an apparatus for estimating an increment in the number of packets arriving at a transmission queue of each terminal and allocating resources to terminals based on the increment in a Demand Assignment Multiple Access (DAMA) satellite communication system, and a method thereof. The method, includes the steps of: a) comparing a summation of requested time slot quantities of terminals with a total number of available time slots; and b) allocating the time slots as much as the requested time slot quantity to each terminal and allocating remaining time slots additionally in proportion to an estimated increase in the number of packets arriving at a transmission queue of each terminal. The apparatus can raise efficiency of resources allocation in DAMA communications and reduce the packet transmission time in a terminal transmission queue.

Apparatus for allocating resources in DAMA satellite communication system and method thereof

Provided is a voltage controlled oscillator having a new type of a resonator and a negative resistance part capable of finely tuning negative resistance. Thus, the voltage controlled oscillator has an excellent quality factor characteristic and can finely tune the negative resistance even after its fabrication is completed. The voltage controlled oscillator having an active element includes: a resonating unit for generating an oscillation frequency according to a resonance capacitance; a frequency tuning unit, connected to a source terminal of the active element, for tuning the oscillation frequency; and a negative resistance adjusting unit, connected to the frequency tuning unit, for generating a negative resistance to adjust the oscillation frequency, the negative resistance adjusting unit including a varactor diode for finely adjusting the negative resistance.

Voltage controlled oscillator capable of tuning negative resistance

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Daejon, South Korea

Ho-Jin Lee