• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.426-433
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• 2006

In this paper, we propose an incremental redundancy(IR)-hybrid ARQ(HARQ) scheme which uses double binary turbo codes for error correction. We also propose a methodology for basic analysis of the throughput which is a performance index of HARQ. The proposed double binary turbo IR-HARQ scheme provides higher throughput than binary IR-HARQ, which uses binary turbo codes for error correction, at all $E_s/N_0$. An extra coding gain is also attained by using the proposed HARQ scheme over the coding gain achieved by turbo codes only.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.3
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• pp.276-284
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• 1987

In this paper, the Hybrid ARQ system using Reed-Solomon code is designed and performance is analyzed. The Hybrid ARQ system performs much better that FEC or ARQ system concerning throughput and reliability especially when the channel error rate is high, approximately $10^{-1}$~$10^{-2}$. Computer Simulation shows that one error is corrected, four errors are detected and codewords which are out of order by retransmission are delivered to the user in order and that performance is excellent.

• The Journal of the Acoustical Society of Korea
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• v.30 no.2
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• pp.86-91
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• 2011

In the underwater communications, the acoustic channel is in poor communication conditions, such as long propagation delay, narrow bandwidth, and high bit-error rate. For these bad acoustic channels, we propose an efficient automatic repeat request (ARQ) for multi-hop underwater network by using the concepts of concurrent bi-directional transmission, multiple sub-packets, and overhearing data packet instead of the acknowledgement signal. Our results show that the proposed ARQ significantly reduces the transmission latency especially in high BER compared with the existing Stop and Wait ARQ.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12C
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• pp.991-996
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• 2008

In this paper, we propose an LDPC-coded hybrid ARQ system using incremental redundancy and retransmission of a part of the transmitted packets. We also present a simple criterion for choosing two methods to support a desired throughput efficiently. Furthermore, we show that the throughput performance can be improved when multi-edge type LDPC codes with the structure of Raptor codes are employed for a hybrid ARQ scheme.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.265-267
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• 2005

RFID 시스템에서 소형화 추세 및 배터리 사용에 따라 태그 및 리더의 전송 전력을 최소화할 수 있는 저전력 설계가 반드시 필요하다. 또한 리더와 Tag는 무선으로 통신을 수행하며, 동시에 Tag는 이동성을 가지므로 에러율이 유선방식에 비해 상당히 높다. 그러나 현재 ISO표준에서는 에러발생시 MAC계층에서 단지 CRC체크 후 재전송을 하는 방식으로 에너지 효율성 및 전송효율이 떨어진다. 본 논문에서는 이 같은 문제를 해결하기 위해서 유통 물류 등에 사용되는 900MHz대역의 RFID시스템에서 에너지 소모 최소화와 신뢰성을 보장할 수 있는 방법으로 Hybrid ARQ를 제안한다. 기존의 Hybrid ARQ를 개선시켜 에너지 효율성을 고려한 최적패킷 길이를 사용하고, 에너지 소모가 적은 BCH Code를 채택한다. 성능 분석 및 시뮬레이션 결과, 제안하는 Hybrid ARQ 방식이 기존의 전송방식보다 에너지 효율성 및 신뢰성을 향상시킴을 보여준다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.4A
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• pp.208-215
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• 2003

In this paper, the target FER is derived to achieve the maximum throughput in H-ARQ scheme where the FEC and ARQ are properly combined and proved through the simulation. In numerical analysis, The average upper bound on the FER(Frame Error Rate) of turbo code is derived and the throughput is expressed in terms of this bound. Then, the throughput is differentiated with respect to the FER and the optimal target PER is achieved. As a result of analysisw, the throughput is maximized at the target FER of 6% whereas the target PER is set to 5% in the current 3GPP2 specification.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.65-68
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• 2003

3GPP's RLC protocol specification adopted an error control scheme based on selective repeat ARQ. In 3GPP ARQ, distinctive windows are provide at transmitting and receiving stations so that those stations are prohibited to send or receive data PDU's out of window. An increase in window size enhances delay performance. Such an increase, however, raises the occupancy at reordering buffer, which results in a long reordering time. Aiming at suppressing the occupancy at reordering buffer, we propose a occupancy control scheme in this paper. In this scheme, a threshold is created in the receiving station's window and a data PDU out of the threshold (but within the window) is treated according to go back N ARQ. By the employment of the occupancy control scheme, the occupancy at the reordering buffer is apparently reduced, while the delay performance may be degraded due to the properties of go back N ARQ. We, thus, investigate the peak occupancy and mean delay performance by a simulation method. From numerical examples, we observe a trade-off in both performance measures and conclude that the peak occupancy is effectively reduced by setting a proper threshold under a constraint on mean delay performance.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.8
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• pp.50-58
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• 2009

Fourth generation mobile communication network have the technology of extensive form include basic service technology and it has been developed from the radio access technology and network topology. Not only fourth generation mobile communication network have basically done new highspeed radio access technology which is suitable to high and low speed environment of transfer, but also it is possible that they have been made for freely vertical handover. ETRI also has made fourth generation mobile communication network which is WiNGS(Wireless Initiative for Next Generation Service) satisfied that demand. This paper is made by lossless handover method through the local retransmission ARQ agent that is one of the main technology of fourth generation mobile communication network. Lossless handover method through local retransmission ARQ agent has been basically made by WiNGS and it was better than original local retransmission of layer by simulation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.421-427
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• 2009

This paper has proposed 1-2-1 coded cooperative communication that is a combination of STBC and ARQ. Coded cooperative communication is a protocol that integrates channel coding with cooperative communication. In this paper consider convolution encoder. ARQ method can increase the spectral efficiency than conventional cooperative communication because if the received signal from source node is satisfied by the destination preferentially, the destination transmits ACK message to both relay node and source node and then recovers the received signal. Where each relay 1, 2 forwards a punctured portion of receive data. When relay transmit to destination apply STBC the reliability to increase. Moreover this protocol can get better BER performance of receiver using simple comparator. We verified BER performance for the proposed protocol through Monte-Carlo simulation over Rayleigh fading plus AWGN.

• Journal of Advanced Navigation Technology
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• v.11 no.3
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• pp.274-280
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• 2007

An ultra-wideband signal is characterized by a radiated spectrum with wide bandwidth around a relatively low center frequency. In this paper, the bit error rate (BER), packet error rate (PER), and data throughput performance for an ultra-wideband system with M-ary correlation receiver are analyze in additive white Gaussian noise (AWGN) and co-channel interference channel. To evaluate the performance of UWB system, a set of UWB communication waveform as pulse position modulated (PPM) signals consisting of more than one UWB pulse is used. The M-ary PPM signals are defined to be equally correlated in order to simplify the system performance analysis. The analysis for system performance shows that the wireless channel error significantly degrades throughput performance and can be effectively increased by hybrid ARQ scheme. Also, an attempt for comparing the data throughput of ultra-wideband system on different performance improvement schemes and parameters has been made. From the performance evaluation process, it is shown that the effects of wireless channel and hybrid ARQ scheme for ultra wideband M-ary PPM system can be evaluated by means of a suitable combination of the PER, throughput vs. signal-to-noise power ratio per bit.