• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.3
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• pp.507-513
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• 2015

In this paper, we present the bit-error rate (BER) performance of quasi-orthogonal space-time block code (QOSTBC) massive multiple-input multiple-output (MIMO) system employing up to 32 transmit and receive antennas. The QOSTBC, due to its advantages in transmission rate and decoding complexity, is an important transmit diversity scheme for more than 2 transmit antennas. As massive MIMO implies very large number of antennas, practically at least more than 15 antennas, a different number of transmit and receive antennas (i.e. $2{\times}2$, $4{\times}4$, $8{\times}8$, $16{\times}16$ and $32{\times}32$) using QOSTBC for the massive MIMO system are considered. The BER performance of the massive MIMO with antennas up to $32{\times}32$ using BPSK modulation scheme is analyzed. Simulation results show that the full-rate massive MIMO systems with QOSTBC give a significant performance improvement due to increasing diversity effect, compared with previously considered massive MIMO systems.

• Journal of Broadcast Engineering
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• v.15 no.4
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• pp.547-554
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• 2010

In this paper, we propose transmission systems for ultra high definition television (UHDTV) through terrestrial transmission by applying the multi-input multi-output (MIMO) technology. The space time block code, hybrid STBC, V-BLAST and linear dis- persion code are considered to support a high data rate of the UHDTV system. The performance of proposed MIMO systems are evaluated through computer simulations. Then we suggest MIMO parameters, number of antennas and optimal transmission scheme to achieve the transmission rate of the UHDTV system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.7
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• pp.413-423
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• 2014

With the increasing demands on high data rate, there has been growing interests in multi-input multi-output (MIMO) technology based on spatial multiplexing (SM) since it can transmit independent information in each spatial stream. Recent standards such as 3GPP LTE-advanced and IEEE 802.11ac support up to eight spatial streams, and massive MIMO and mm-wave systems that are expected to be included in beyond 4G systems are considering employment of tens to hundreds of antennas. Since the complexity of the optimum maximum likelihood based detection method increases exponentially with the number of antennas, low-complexity SM MIMO detection becomes more critical as the number of antenna increases. In this paper, we first review the results on the detection schemes for SM MIMO systems. In addition, massive MIMO reception schemes based on simple linear filtering which does not require exponential increment of complexity will be explained, followed by brief description on receiver design for future high dimensional SM MIMO systems.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.545-548
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• 2003

MIMO-OFDM 시스템은 다중 안테나 송신을 통하여 시스템의 capacity를 극대화 하지만, 이를 위해서는 정확한 채널계수 값의 추정을 필요로 한다. 본 논문에서는 MIMO-OFDM시스템을 위한 채널계수 추정기법으로서 Space-Time Coding(STC)에 기반을 둔 방식을 제안한다. 제안된 채널 계수 추정 기법을 위해 필요한 심볼 구조, frame 구조를 IEEE 802.11a 시스템에 적용하였다. VBLAST 기법이 적용된 IEEE 802.11a 기반의 4 by 4 MIMO-OFDM 시스템에 대한 모의 실험을 통하여 제안된 방법의 성능과 기존의 방법의 성능을 coded BER를 통해 비교 분석해 보았다.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.204-207
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• 2003

MIMO-OFDM 시스템은 다중 안테나 송신을 통하여 시스템의 capacity를 극대화하지만, 이를 위해서는 정확한 채널 계수 값의 추정을 필요로 한다. 본 논문에서 는 MIMO-OFDM 시스템을 위한 채널계수 추정기법으로서 Space-Time Coding(STC)에 기반을 둔 방식을 제안한다. 제안된 채널계수 추정기법을 위해 필요한 심볼구조, frame 구조를 IEEE 802.11a 시스템에 적용하였다. VBLAST 기법이 적용된 IEEE 802.11a 기반의 4 by 4 MIMO-OFDM 시스템에 대한 모의실험을 통하여 제안된 방법의 성능과 기존의 방법의 성능을 coded BER를 통해 비교 분석해 보았다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.6
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• pp.81-88
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• 2012

Space diversity and space multiplexing gain can be achieved with MIMO system. This paper proposes spatial coding method to MIMO system using data information and antenna selection technique. This technique provides coding gain as well as space diversity gain. For MIMO system with BPSK modulation, BER performance is analyzed and space diversity gains are compared through simulation in terms of data maldistribution degree.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.447-450
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• 2009

In this paper, binary pulse-antipodal modulation (2PAM) direct-sequence (DS) ultra-wideband (UWB) system is applied to multiple input multiple output (MIMO) system using vertical bell lab layered space-time (V-BLAST) structure to achieve high-data-rate communications over indoor wireless channels. The relationship between antenna dimension and BER performance of 2PAM DS UWB MIMO system is discussed. In the receiver of UWB-MIMO system, various MIMO detection algorithms such as zero-forcing (ZF), ZF-ordered successive interference cancellation (OSIC), minimum-mean-square-error (MMSE), MMSE-OSIC and maximum likelihood (ML) are comparatively studied.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.6
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• pp.444-451
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• 2017

In this paper, we have evaluated and analyzed OTFS(Orthogonal Time Frequency Space) modulation and OTFS-MIMO(Multiple Input Multiple Output) system. OTFS modulation can concisely compensate delay-Doppler spreading effect by using 2D(2-Dimension) iDFT (inverse Discrete Fourier Transform) and DFT(Discrete Fourier Transform) operation. It enables OTFS system to transmit high-speed data. Especially, OTFS-MIMO system can transmit all data streams without performance degradation on high Doppler frequency channel. As simulation results, we have confirmed that $1{\times}1$ OTFS system's achievable rate is a similar to each stream of $2{\times}2$ OTFS-MIMO system. That is, we have also confirmed that $2{\times}2$ MIMO system can completely achieve double achievable rate in comparison with OTFS system on high Doppler frequency channel.

• 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.

• Journal of Broadcast Engineering
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• v.22 no.6
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• pp.755-764
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• 2017

In this paper, we design transmitter and receiver structures for a $2{\times}2$ multiple-input multiple-output (MIMO) in ATSC 3.0 systems and analyze the performance of the $2{\times}2$ MIMO system. In the ATSC 3.0 MIMO systems, spatial diversity and multiplexing gains can be obtained using the spatial demultiplexer and precoder. In this paper, we present the structures of the transmitter and receiver for ATSC 3.0 MIMO systems. Also, we present performance results of the $2{\times}2$ MIMO system through computer simulations.