• 한국멀티미디어학회논문지
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• 제8권6호
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• pp.798-806
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• 2005

In this paper, we suggest a game system that can support network modules for multi-platform based video games, and built a system that can convert from a single-user game to multi-user game. In this system, we bring in an initial delay buffering scheme on clients to handle any periods of latency occurring from the load fluctuation in a network, when a real-time game is played, and shows that stable play for a game is achieved as the result of the scheme. This paper also presents a retransmission algorithm based on the history of game commands to handle drawbacks of UDP mechanism. And, we evaluate the network delay and packet loss using the simulation tool NS2, and shows the case of 0.3 second buffer delay is the most suitable for recovery.

• Journal of Communications and Networks
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• 제8권2호
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• pp.212-219
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• 2006

In this paper, a new turbo codes-based hybrid automatic repeat request (TC-HARQ) scheme with segment selective repeat (SSR) is proposed. The main strategy is, upon retransmission, to repeat the data that are most important for the next round of decoding based on the distribution of residual errors after current decoding. The performance in terms of reliability and throughput is analyzed. To adapt to correlated fading channels where an inter-leaver is always employed before transmission, we further modify the SSR strategy so that data having experienced correlated deep fading are selected for retransmission. Finally, this proposed scheme is applied to the wideband code division multiple access (WCDMA) system under frequency selective fading channels. Simulation results demonstrate that in all single and multiple user cases, SSR-based TC-HARQ leads to significant throughput improvement with similar bit error rate (BER) performance as compared to type-I TC-HARQ.

• 대한전자공학회논문지TC
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• 제46권5호
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• pp.19-25
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• 2009

본 논문은 물리 계층에서의 HARQ방식에서 사용하는 체이스 결합 기반의 재전송 방법에서 재전송시 신호 성상점 재배치방법에 따른 성능 분석 결과를 제시한다. 성능 분석은 16QAM 변조방식에 국한하여 가산형 백색 가우스 잡음 (AWGN) 환경에서 모의실험을 통해 이루어진다. 터보 부호와 길쌈 부호의 두 가지 채널 부호화 방법에 따른 성능 분석 결과를 제시한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.133.3-133
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• 2001

This paper analyses the real-time performance of Ethernet based intranet whether it is applicable to the real-time network. Unpredictability of transmission delay by collision-delay-retransmission mechanism in CAMA/CD(Carrier Sense Multiple Access with Collision Detect) of Ethernet is the major reason making hard to apply to real-time system. Both retransmission mechanism of TCP(Transmission Control Protocol) for reliability and sliding windows algorithm for high utilization make hard to predict transmission delay. Because real-time control network require fast responsibility and bustle of short-periodic messages, global-clock for collision avoidance and UDP(User Datagram Protocol) for high utilization of network are used. The mathematical models for time-delay that can be occured between ...

• 전자공학회논문지A
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• 제33A권2호
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• pp.32-39
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• 1996

Hybrid decision decoding for the extended hamming codes without retransmission, which is a combination of hard and soft decision decoding, is proposed and its performance is analyzed in this paper. As results, hybsrid decision decoding shows a little bit higher residual bit error rate than soft decision decoding. However, as the size of the extended hamming code increases, the difference of th enumber of comparisons increases further. In addition, hybrid decision decoding shows almost same residual bit error rate as hard decision decoding with retrassmission and shows much lower residual bit error rate than hard decision decoding without retransmission.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(3)
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• pp.47-50
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• 2002

In this paper, the efficient transmission technique of real time video data over 3G wireless networks is presented. To understand the transmission characteristic of 3G networks on real time video data, we implemented the data transport structure of 3G wireless networks. Also this research is based on current 3G wireless network specification of 3GPP, 3GPP2 standard organization to evaluate the result over real 3G wireless network environment. The retransmission by radio link layer results in the delay factor. To implement video data transmission efficiently, we Propose to use both no-retransmission and forward error correction method.

• 전자공학회논문지A
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• 제31A권4호
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• pp.21-29
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• 1994

Three protocols based on the slotted Aloha technique are proposed for very high-speed optical fiber local area networks using wavelength division multiplexing (WDM) passive star topology and the throughputs and delays are derived. For getting a high probability in successful transmission of control packets determining the transmission of a data packet, we adopt control mini slot groups in these protocols. The retransmission probability is also considered in analysis. Both throughput and delay of three protocols are compared and analyzed by varying the number of control solt groups, the retransmission probability the length of a data packet and the number of channels. The numerical analysis shows that the proposed protocols adopted the control slot groups give the increase of throughput and the decrease of delay.

• Journal of electromagnetic engineering and science
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• 제12권3호
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• pp.189-195
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• 2012

In this paper, we propose a novel protocol called a Multi-hop Diversity Transmission protocol in which the retransmission is realized by a relay that is Nearest to a current Source (MDTNS). We derive the mathematical expressions of the packet error rate (PER) and the average number of transmissions over Nakagami-m fading channels, and verify them by Monte Carlo simulations. The simulation results show that the MDTNS protocol improves the performance of the network in terms of PER when compared to the Multi-hop Diversity Transmission protocol in which the retransmission is done by a relay that is Nearest to Destination (MDTND) and to the conventional multi-hop transmission (CMT) protocol.

• Journal of information and communication convergence engineering
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• 제5권3호
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• pp.194-199
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• 2007

In this paper, a slotted CDMA_ALOHA protocol with hybrid ARQ is proposed for the wireless CDMA communication networks. The proposed protocol combines the characteristics of the slotted ALOHA, CDMA, and the hybrid ARQ, in order to increase the throughput by reducing the number of retransmissions when the channel experiences heavy traffic. The main feature of the proposed protocol is the utilization of the forward error correction capability to correct errors that appear after the CDMA dispreading of the packets. The base station does not need to ask so often for retransmission of erroneous packets. It will request for retransmission only when the FEC capability is exceeded. The performance of the proposed protocol is analyzed by considering the packet collision probability as well as the bit error probability. The numerical results show that the system throughput is closely related to the bit error rate of the wireless link and the FEC coding rate.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 B
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• pp.633-636
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• 1998

The next generation of wireless communication seems to be multimedia communications based on ATM and requires the efficient MAC(Medium Access Control) protocol to support multimedia traffic with the various characteristics of QoS(Quality of Service). A Proposed D-PRMA++ MAC protocol is operated dynamically by the retransmission probability and the number of reservation channel on the side of MS(Mobile Station) Also, On the side of BS(Base Station) it analyzes the parameters receive d from all MS and allocates the slots by priority in order to guarantee QoS.