• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.4
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• pp.713-720
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• 2018

The Signal Intelligence (SIGINT) system based on Angle-of-Arrival(AOA) estimation, interference suppression, and transmission beamforming techniques is a cutting edge technology for efficiently collecting various signal information. In this paper, we present the efficient structure of a satellite system consisted of an AOA estimator, an adaptive beamformer, a signal processing and D/B unit, and a transmission beamformer, for collecting signal information. For accurately estimating AOAs of various signals, efficiently suppressing interference or jamming signals, and efficiently transmitting the collected information or data, we employ Multiple Signal Classification (MUSIC), Minimum Variance Distortionless Response (MVDR), and Minimum Mean Square Error (MMSE) algorithms, respectively. Also, we evaluate and analysis the performance of the presented satellite system through the computer simulation.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.4
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• pp.333-339
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• 2017

Transmission signal in wireless environment receives a signal in which a source signal, interference, and noise are mixed. The goal of this study is to estimate the desired signal from the received signal. In this paper, we have studied a method correctly estimating a target in spatial by modified beamformer method. The modified bemaformer uses an adaptive array antenna and perturbation matrix to obtain the optimal weight, and estimate the desired signal by radiating the beam in spatial. We estimate a desired signal of the target by improving resolution with the modified beamformer method which does not have complicated calculation amount. Through simulation, we compare and analyze the modified beamformer method and the MUSIC method with good resolution. In result of simulation, we showed that modified beamformer method has better resolution of 10degree than classical beamformer method and showed similar performance as the MUSIC method. The resolution of this paper was estimated to be about 5 degrees.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.29-32
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• 2002

본 논문은 수평적 시공간 부호화 기법(Horizontal Space-Time Coding)과 송수신단에 별도의 빔형성 기법을 결합한 JBSTC(Joint Beamforming Space-Time Coding) 구조에 대한 제안 및 동작원리를 기술하고 성능을 분석하였다. JBSTC는 MIMO(Multi-Input Multi-Output) 송수신 시스템 채널 모델링을 기반으로 송신측 안테나간 상호 상관 행렬과 수신측 안테나간 상호 상관 행렬을 이용하여 송수신 빔형성기의 안테나 가중치들을 계산한다. 본 논문에서 제안하는 JBSTC 방식은 송수신단에서 발생하는 안테나 간격과 각퍼짐에 따른 상호 상관 값을 효과적으로 보정함으로써 기존의 수평적 시공간 부호화 기법보다 우수함을 알 수 있다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.1
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• pp.24-31
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• 2009

In this paper, the new technique combing power control with Pre-FFT beamforming is proposed for MIMO(multi-input multi-output)-OFDM(orthogonal frequency division multiplexing) system. As combining the proposed power control with beamforming, we can iteratively control the transmittingpower and update the weight of beamformer together. And then, the beam is formed toward the desired direction and SNIR of each subcarrier is converged to target SNIR. Therefore, the performance of MIMO-OFDM system is very improved. BER performance improvement of the proposed approach is investigated through computer simulation by combining power allocation algorithm with MIMO-OFDM system using Pre-FFT beamformer

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.296-299
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• 2003

In this paper, an underwater acoustic digital transceiver is designed and implemented by a multiple DSPs system. We have designed a QPSK transmitter based on look-up table and 13-symbols Barker code is used for frame synchronization. Channel distortions are compensated by a wide-band beamformer based on FIR filter and an adaptive equalize. with RLS algorithm. Uniform linear array (ULA) with four elements is used for the spartial signal processing. 1/2 convolutional code and Viterbi decoder are implemented to overcome time-varying multi-path fading. Also, we show experimental results in the underwater anechoic basin at KRISO/KORDl and Goseong, Donghae and Soyang lake of Kangwon-do.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1207-1212
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• 2018

The signal intelligence (SIGINT) technology is actively used for collecting various data, in a number of fields, including a military industry. In order to collect the signal information and data and to transmit/receive the collected data efficiently, the accurate angle-of-arrival (AOA) information is required and communication disturbance from the interference or jamming signal should be minimized. In this paper, we present the structure of an adaptive beam-forming satellite system based on the planar array antenna, for collecting and transmitting/receiving the signal information and data efficiently. The presented adaptive beam-forming system consists of an antenna in the form of a planar array, an AOA estimator based on the Multiple Signal Classification (MUSIC) algorithm, an adaptive Minimum Variance Distortionless Response (MVDR) interference canceler, a signal processing and D/B unit, and a transmission beamformer based on Minimum mean Square Error (MMSE). In addition, through the computer simulation, we evaluate and analyze the performance of the proposed system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1271-1277
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• 2008

This paper proposes the code acquisition scheme on a MIMO channel for preamble search in a CDMA-MIMO uplink system. The multiple transmit/receive antennas are used for beamforming. The performance of a ML code acquisition technique based on transmit and receive beamforming is analyzed by considering rho detection probability. The acquisition performance and MAT for a MIMO code acquisition system are numerically evaluated. It is shown that multiple transmit antennas can give the code acquisition system a transmit beamforming gain and result in much better performance than a SIMO case.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5A
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• pp.493-500
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• 2006

This paper presents the efficient structure and parameter optimization of downlink beamforming transmitter in OFDMA/TDD system. To design downlink beamforming transmitter for multiple transmit antennas, an efficient beamforming structure for multiple users and the choice of word-length of each block are critical in the aspect of its performance and hardware complexity. We propose an efficient beamforming scheme, which stores the weights of subcarriers into memory without user identification at the receiver of base station and calculates the weights for corresponding user in a subcarrier unit of IFFT input at high speed. Also, we obtain the word-length of main data path and other design parameters by fixed-point simulation analysis. The proposed architecture could reduce the memory size proportional to the maximum number of users per frame, and the processing time of an OFDM symbol at the receiver of base station without the need of additional processing time for calculating the weights at the transmitter.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.468-472
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• 2000

This paper discusses the development of a acoustic vector channel simulator for the performance analysis of a acoustic digital communication system. The channel simulator consists of transmission module, acoustic channel model, receiver, beamformer, and adaptive equalizer. QPSK source signal is generated by the parameters specified by a user and transmitted. The transmitted signal generate multipath signals which have a different delay, amplitude, and dopper Sequency. The multipath signals with the acoustic noises is the received signal. We can analysis the communication system performance according to the antenna structure, beamforming algorithm, and equalization algorithm.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.53-60
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• 2013

In this paper, the new multi-beamforming is proposed for Multiple-input multiple-output (MIMO) Multicarrier-Code division multiple access(MC-CDMA) systems to overcome the decrease of performance due to multiuser interference and multiple-antenna interference. Installing the number of multi-beamformer which is equal to the number of multi-transmitter antennas and exploiting the proposed approach at the receiver of MIMO MC-CDMA, the multi-beams are formed toward each multi-antenna of desired user and null beam are formed to other interference. Therefore, the performance of MIMO MC-CDMA system is improved as removing the interference signal. BER performance improvement is investigated through computer simulation by the proposed approach to MIMO MC-CDMA system.