• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.3
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• pp.34-39
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• 2008

In this paper, we propose a bit-interleaved coded modulation (BICM) a lied to improved super-orthogonal space-time block code(SOSTBC). The proposed system achieves a greater diversity gain than that of super-orthogonal space-time trellis code (SOSTTC) with similar decoding complexity. Since, using the improved SOSTBC, the bit diversity carl be full diversity of SOSTBC. In contrast, BICM applied to Jafarkhani's SOSTBC is difficult to achieve a greater diversity gain than that of SOSTTC, because every bit diversity of the system is 1.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7C
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• pp.644-651
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• 2007

In multiple antenna systems, vertical Bell Labs Layered Space-Time (V-BLAST) systems enable very high throughput by nulling and cancelling at each layer detection. In this paper, we propose a V-BLAST system which combines with signal space diversity technique. The benefit of the signal space diversity is that we can obtain an additional gain without extra bandwidth and power expansion by applying inphase/quadrature interleaving and the constellation rotation. Through simulation results, it is shown that the performance of the proposed system is less than 0.5dB away from the ideal upper bound.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.12
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• pp.28-33
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• 2007

We present a space-time trellis coded OFDM system in flow fading channels. Generalized principal ratio combining (GPRC) is also analyzed theoretically in frequency domain. The analysis show that the decoding metric of GPRC include the metrics of maximum likelihood (ML) and PRC. The computer simulations with M-PSK modulation are obtained in frequency flat and frequency selective lading channels. The decoding complexity and simulation running times are also evaluated among the decoding schemes.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.26-27
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• 2015

본 논문에서는 대역폭 효율을 향상시키는 공간 변조(spatial modulation) 다중 안테나 시스템을 제안한다. 기존의 공간 변조 다중 안테나 시스템은 다중 송신 안테나 중 하나의 안테나를 사용하여 채널 간에 간섭을 피할 수 있어서 다중 경로가 많은 실내 환경에서 적합하다. 그러나 심벌 전송 구간마다 한 개의 안테나만을 선택하여 전송하므로 다중 안테나의 최대 부호 이득을 얻을 수 없다. 이를 극복하기 위하여 시공간블록부호화 방식을 적용한 공간 변조 다중 안테나 시스템은 두 개의 안테나를 사용하여 수신 성능을 향상시키지만 대역폭 효율이 향상되지 않는 단점이 있다. 본 논문에서는 Hybrid STBC 시스템을 적용한 공간 변조를 제안하여 공간 변조 다중 안테나 시스템의 대역폭 효율을 개선한다.

• ETRI Journal
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• v.28 no.1
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• pp.87-90
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• 2006

In this letter, we propose a quasi-orthogonal space-time-frequency (QOSTF) block coded orthogonal frequency division multiplexing (OFDM) that can achieve full symbol rate with four transmit antennas. Since the proposed QOSTF-OFDM cannot achieve full diversity, we use a diversity advantage collection with zero forcing (DAC-ZF) decoder to compensate the diversity loss at the receiving side. Due to modulation advantage and collected diversity advantage, the proposed scheme exhibits a better bit-error rate performance than other orthogonal schemes.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.1-8
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• 2010

Multi antenna techniques using space-time codes can achieve diversity gains in a multi-path environment without additional bandwidth requirement. Most of the 4G candidate standards including the IEEE 802.16e adopt multi-input multi-output (MIMO) schemes to achieve either high throughput performance or diversity gains. In these 4G candidate standards, turbo codes using an iterative decoder with soft input soft output are used to overcome serious channel fading. For this reason, the estimated signal values from MIMO detectors should be soft decision detection values. In this paper, we propose efficient methods to estimate soft decision detection values for various space time coding schemes, and provide the simulation results of turbo coded space time coding scheme over an IEEE 802.16e link.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.4 s.316
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• pp.117-122
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• 2007

For multiple antenna systems, we consider the hybrid iterative detection of the maximum a posteriori probability(MAP) detection and the linear detection such as the minimum-mean-square-error(MMSE) filtering with soft cancelation. We devise methods to obtain both the lower complexity of the linear detection and the superior performance of the MAP detection. Using the a prior probability of the coded bit which is extrinsic of the outer decoder, we compute the threshold of grouping and determine the detection scheme symbol by symbol. Through the simulation results, it is shown that the proposed receiver obtains the superior performance to the MMSE detector and the lower complexity than the MAP detector.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.3
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• pp.167-167
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• 2004

The system combined layered space-time processing and space-time trellis codes (STTC) provide high transmission rate as well as diversity and coding gain without bandwidth expansion. In this paper, two layered receiver structures are proposed. One is the LSTT-MMSE in which received bit streams are decoupled by interference nulling and then decoded by separate STTC decoders. The decoded outputs are cancelled from the received signal before advancing to the next layer detection. The other is LSTT-Whitening employing whitening rather than nulling. The receiver employing whitening process shows several advantages on diversity gain and the required number of receive antennas compare to the convolutional coded space-time processing. The proposed receivers use different decoding order scheme according to each interference suwression. The (4, 3) LSTT-Whitening receiver still achieves 1㏈ gain over the (4, 4) LSTT-MMSE and the (4, 4) coded layered space-time processing.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.3
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• pp.9-14
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• 2004

The system combined layered space-time processing and space-time trellis codes (STTC) provide high transmission rate as well as diversity and coding gain without bandwidth expansion. In this paper, two layered receiver structures are proposed. One is the LSTT-MMSE in which received bit streams are decoupled by interference nulling and then decoded by separate STTC decoders. The decoded outputs are cancelled from the received signal before advancing to the next layer detection. The other is LSTT-Whitening employing whitening rather than nulling. The receiver employing whitening process shows several advantages on diversity gain and the required number of receive antennas compare to the convolutional coded space-time processing. The proposed receivers use different decoding order scheme according to each interference suwression. The (4, 3) LSTT-Whitening receiver still achieves 1㏈ gain over the (4, 4) LSTT-MMSE and the (4, 4) coded layered space-time processing.

• Journal of Broadcast Engineering
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• v.28 no.1
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• pp.145-148
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• 2023

Open-loop Octonion space-time block code for 4 transmit antenna system is considered and random phases are applied to 4 transmit antennas for physical layer security. When an illegal hacker estimates the random phases of 1 through 4 transmit antennas with maximum likelihood (ML), this letter analyzes the bit error rate (BER) performances versus signal-to-noise ratio (SNR). And the Octonion code in the literature[1] does not have full orthogonality so, this letter employs the perfect orthogonal Octonion code. When the hacker knows that the random phases are 2-PSK constellations and he should estimate all the 4 random phases, the hacking is impossible until 100dB. When the hacker possibly know that some of the random phases, bit error rate goes down to 10^-3 so, the transmit message could be hacked.