Electronics and Telecommunications Research Institute

Industrial Cooperation Foundation Chonbuk National University

Hee-Wook Kim

Do-Seob Ahn

Kun-Seok Kang

Bon-Jun Ku

Soo-Young Kim

Sooyoung Kim

Tae-Chul Hong

Seung-Hyun Nam

A transmission apparatus and method for implementing frequency selectivity in a multi-beam satellite system that transmits a signal to user equipment through one or more antenna feed groups. The transmission apparatus includes: an antenna feed group selecting unit configured to select one or more antenna feed groups from the one or more antenna feed groups; a cyclic delay offset determining unit configured to determine a cyclic delay offset according to a determination result of the antenna feed group selecting unit; and a transmitting unit configured to apply the cyclic delay offset determined by the cyclic delay offset determining unit to a signal to be transmitted through the one or more antenna feed groups selected by the antenna feed group selecting unit, and to transmit a resultant signal.

Apparatus and method for providing frequency selectively in satellite communication system

Disclosed are an apparatus and a method for normally receiving data by accurately estimating and compensating for a frequency offset for a wireless frequency channel through which data are transmitted in a communication system under wireless frequency environment. In the present invention, data transmitted through the wireless frequency channel are received, the frequency offset in the wireless frequency channel from the receive data is estimated based on an interpolation scheme using the periodogram, and the frequency offset is compensated to receive the data by frequency-synchronizing with the wireless frequency channel.

Apparatus and method for receiving data in communication system

A signal processing technology for allowing a repeater to transmit a signal received from an external apparatus to a terminal is provided. In a satellite system, a signal transmitted from a satellite or transmitted to a satellite is subject to a low order modulation, and a terrestrial repeater performs a high order modulation on signals and retransmits the signals.

Signal processing method for terrestrial repeater

A diversity method using an error correcting code. The diversity method includes creating a mother code by performing error correction coding on an input bit string to be coded, puncturing the created mother code and acquiring an error correcting code including systematic information and partial parity information, and space-time encoding the acquired error correcting code corresponding to each frequency.

Diversity method using error correcting code

Provided is a satellite communication system for obtaining a diversity gain by transmitting a signal applied with STBC. When a signal transmission band of a link between a satellite and a terminal differs from that of a link between a satellite and a repeater, the satellite communication system includes: a satellite for transmitting a first signal encoded to STBC using a band of a link formed between the satellite to a terminal and transmitting a second signal encoded to STBC using a band of a link formed between the satellite to a repeater; and at least one of frequency transforming repeaters for receiving the second signal through the band of the link formed between the satellite to the repeater, transforming the received second signal to a signal with other frequency band, and transmitting the transformed second signal using a band of a link formed to a terminal.

Signal transmission mechanism with diversity gain in satellite communication network

Provided are a time synchronization method and a frequency offset estimation method using the same in an OFDM system. The time synchronization method using a preamble transmitted from a transmitter to a receiver in the OFDM communication network includes the steps of: a) calculating a moving sum of a first sequence and a second sequence obtained by a product of neighboring elements in a received signal when the received signal containing a preamble is received from the transmitter; b) estimating a location of the received signal corresponding to the moving sum having a maximum value; and c) acquiring a time synchronization with respect to the received signal, based on the estimated location, wherein the first sequence is obtained from a product of neighboring elements in the preamble and a correlation value obtained by correlating another sequence with the first sequence is smaller than a predetermined value.

Growing community of inventors

Daejeon, South Korea

Hee-Wook Kim