• Journal of Korea Society of Industrial Information Systems
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• v.25 no.2
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• pp.29-37
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• 2020

This paper proposes a multiple-relay-assisted single side band (SSB) space frequency block code (SFBC) single carrier (SC)-frequency division multiple access (FDMA) system and measures the performance of SSB SFBC SC-FDMA transmission system with the signal-to-noise power ratio SNR) between relays and a destination station. As we know, the performance of relay-assisted transmission systems can be easily improved by re-transmitting to the destination station after applying block code to the recovered transmitted signals of relays. In this paper, the performance improvement of the relay-assisted SSB SC-FDMA system can be obtained without any significant increase of system computational complexity by implementing block code with the complex conjugates symmetric characteristic of SSB system. The simulation result shows that the SNR performance of the proposed multiple-relay-assisted SSB SFBC SC-FDMA system is about 4 dB better than the performance of the single-relay-assisted SSB SC-FDMA system at the symbol error rate of 10^-2.

• Journal of IKEEE
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• v.11 no.4
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• pp.340-347
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• 2007

This paper proposes a new class of Space-Time Block Codes, which is manipulated from the existing transmit diversity schemes. We analyze the performance and the receiver complexity of the proposed scheme and confirm that the new diversity scheme can yield performance gain over other existing four-transmit antenna cases. By relaxing the diversity criterion on code designs, the proposed space-time code provides a full transmission rate for four-transmit antennas and makes it possible to approach the open-loop Shannon channel capacity. Outage capacity and simulation results are used to show that substantial improvements in performance while maintaining a simple linear processing receiver structure are obtained in frequency selective channels.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.5
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• pp.25-32
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• 2007

This paper proposes a distributed space-frequency block code (SFBC) for relay-assisted single carrier frequency-domain equalization (SC-FDE). The proposed technique achieves spatial diversity gain over fast fading channels without the complexity of multiple antennas. The mobile equipment of the proposed system has a very simple transmitter structure with constant amplitude transmit sequences, which is desirable especially for uplink communications. In order to obtain spatial diversity, the transmit sequence of relay is efficiently generated in the time domain, which is equivalent to the SFBC. Further, efficient implementation of relay and destination structures is also presented. Extensive simulation results show that the proposed system significantly outperforms the distributed space-time block code (D-STBC) SC-FDE over fast fading channels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10A
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• pp.968-975
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• 2006

Research about the mode of MIMO that can get a coding benefit at the same time with a diversity benefit using a multiple antenna at the fading channel for a high-speed data transmission have been processed actively But the analysis about the interference of UWB system comes not to consist yet. So this paper analyzed the performance of the interference of UWB system to SFBC-OFDM and SFTC-OFDM system that applied a space block code which has a space diversity characteristic to OFDM system at MIMO channel. We shelved the performance that SFTC-OFDM system is robuster than SFBC-OFDM system under MB-OFDM UWB Interference.

• Journal of Korea Society of Industrial Information Systems
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• v.26 no.6
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• pp.1-9
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• 2021

In order to increase frequency transmission efficiency, single side band(SSB) transmission systems with the complex conjugate symmetry characteristics on a frequency domain have been studied. In addition, orthogonal block codes(space-time or space-frequency block code(SFBC)) for the diversity performance gain of transmission systems have been widely researched. In this paper, we implement a 3/4-rate SFBC SSB single-carrier(SC) frequency division multiple access(FDMA) system with 4 transmit antennas. It can be shown from the simulation results that the proposed SFBC SSB SC FDMA system using the 3/4-rate 4×4 orthogonal block code outperforms the conventional SSB SC FDMA system and the 2×2 SFBC SSB SC FDMA system with 2 transmit antennas.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11A
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• pp.1154-1163
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• 2007

For orthogonal frequency division multiplexing (OFDM), cyclic prefix (CP) should be longer than the length of channel impulse response. In order to prevent a loss of bandwidth efficiency due to the use of a CP, residual intersymbol interference cancellation (RISIC) method has recently been developed. In this paper, we first apply the RISIC algorithm to the space-time block coded (STBC) OFDM and the space-frequency block coded (SFBC) OFDM with insufficient CP. It is shown that in the STBC OFDM, tail cancellation as well as cyclic restoration of the RISIC should be repeated. Second, we propose iterative channel estimation method for the RISIC in the STBC OFDM system with insufficient CP. Based on the expectation-maximization (EM) algorithm, the proposed estimation method exploits the extrinsic probabilities of the channel decoder iteratively. The performance of the proposed method is evaluated by computer simulation in a multipath fading environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2A
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• pp.195-202
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• 2007

A differential space-frequency block code - orthogonal frequency division multiplexing (SFBC-OFDM) scheme as a multiple-input multiple-output (MIMO) transmission technique for next-generation digital multimedia broadcasting (DMB) is proposed in this paper. A linear decoding method for differential SFBC, which performs comparably to the ML decoding method, is derived for the cases of two or four transmit antennas. A simple table lookup method is proposed to improve the efficiency of the encoding/decoding process of DSFBC for the case of non-constant modulus constellations. A DMB MIMO channel model, developed by extending the 3GPP MIMO model to fit DMB environments, is used to compare BER performances of differential space block code schemes for various channel environments. Simulation results show that the differential SFBC-16QAM scheme using either four transmit antennas with one receive antenna or two transmit antennas with two receive antennas achieves a performance gain of 12dB than that of the conventional DQPSK scheme, even with a data rate twice faster.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.423-429
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• 2019

Recently, a variety of methods for the performance improvement of ultra-high speed wideband wireless transmission systems have been suggested. This paper proposes a space-frequency (SF) block coded single side band (SSB) single carrier (SC)-frequency division multiple access (FDMA) transmission system. In the proposed SSB SC-FDMA system, SF block code is implemented with the complex conjugates, which are formed from discrete Fourier transform (DFT) spreading of pulse amplitude modulation (PAM) signals. As a result, transmit diversity gain can be obtained in the proposed SF block coded SSB SC-FDMA system without any significant increase of the system computational complexity. The simulation result shows that the signal-to-noise power ratio (SNR) performance of the proposed SF block coded SSB SC-FDMA system is approximately 4 dB better than the SNR performance of the conventional SSB SC-FDMA system with single transmit antenna at a symbol error rate (SER) of $10^{-2}$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5776-5782
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• 2014

Relay-assisted wireless communication systems have been studied widely to cope with shadow areas and extend the cell coverage. This paper proposes a space-frequency (SF) block coded single carrier-frequency division multiple access (SC-FDMA) transmission system in a relaying multi-path shadow area and present the performance comparison of SC-FDMA systems based on the signal-to-noise power ratio (SNR) between a relay and a destination station. The performance of relaying SC-FDMA systems can be improved by applying SF block code to the recovered signals of relays before re-transmitting them. The simulation result showed that the SNR performance of the proposed SF block coded relaying SC-FDMA system was approximately 5 dB better than the SNR performance of the single-path relaying SC-FDMA system at a symbol error rate (SER) of $10^{-2}$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.611-614
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• 2012

Space-Time Block Code (STBC) is a simple transmit diversity scheme mitigating detrimental effects of fading channel. However, STBC receivers require channel knowledge and suffer from inaccurate channel estimation. Differential Space-Time Modulation (DSTM) renders the receiver a choice of coherent detection or non-coherent detection, depending on the availability of the channel information. Based on the simulated BER performances of these two schemes over various normalized Doppler frequency scenarios using LTE-like parameters, a benefit of adaptively switching the receiver type is investigated.