• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.5
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• pp.1208-1220
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• 1996

In this paper, the performance of a Carrier Sense Multiple Access/Collision avoidance (CSMA/CA) protocol using stop-and-Wait automatic Repeat reQuest, which is adapted as a draft standard in IEEE 802.11, is analyzed using a mathematical method based on a renewal theory, and simulation checks are performed, which confirm the goodness of our anlysis. In order to anlayze of CSMA/CA, we model that network is composed of finite populationand channel is slotted. And, we consider the CSMA/CA protocol as a hybrid protocol of 1-persistent CSMA and p-persistent CSMA protocol. As resuls of analysis, we have found that the throughput is degraded and packet delay is increased as the number of stations, Acknowledgement (ACK) length and Distributed coordination function Inter Frame Space (DIFS) length are increased.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3A
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• pp.406-411
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• 2000

In wireless ATM system, powerful FEC code is required for highly reliable data transmission. In this paper, we propose an adaptive hybrid ARQ scheme using RCPSCCC for WATM system. The code rate of RCPSCC is adjusted to match channel conditions and data types. By using only the effective free distances of outer and inner encoders, we derive upper bounds of the bit and word error probabilities over Rayleigh and Rician fading channels. By applying RCPSCC to the adaptive hybrid ARQ protocol, highly reliable data transmission can be achieved.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.1862-1867
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• 1999

In wireless ATM system, powerful FEC code is required for highly reliable data transmission. In this paper, we propose an adaptive hybrid ARQ scheme using RCPSCCC for WATM system. The code rate of RCPSCCC is adjusted to match channel conditions and data types. By using only the effective free distances of outer and inner encoders, we derive upper bounds of the bit and word error probabilities over Rayleigh and Rician fading channels. By applying RCPSCCC to the adaptive hybrid ARQ protocol, highly reliable data transmission can be achieved.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1136-1144
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• 2010

In this paper, the effects of HARQ feedback error are evaluated in IEEE 802.16m system when the HARQ and ARQ interactions that utilize the HARQ feedback information is used. Also, the HARQ and ARQ interaction scheme considering HARQ feedback errors are proposed. The HARQ and ARQ interaction scheme improve the system throughput by using the HARQ feedback information instead of the ARQ feedback message, which reduce retransmission time. However, errors in the HARQ feedback information generate severe performance degradation. Especially, the local NAK errors between HARQ feedback error critically degrade the performance, because the local NAK errors lead the loss of ARQ blocks. We propose a channel state-based schemes for HARQ and ARQ interactions to mitigate the throughput degradation due to HARQ feedback errors. Simulation results show that the proposed scheme improves the throughput and the delay performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.1
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• pp.95-101
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• 2009

Wireless Sensor Network (WSN) has limited power and bandwidth. In order to high data rate and high speed communication systems are required. Cooperative communication system can help to decrease power consumption through spatial diversity. In cooperative transmission, one partner node assists one sensor node to transmit their data to destination. Instead of using M partners for M sensor nodes, we propose 1 partner for M sensor nodes. And we proposed relay selection scheme base on ARQ. Proposed protocol offers higher diversity order as conventional one with much less bandwidth and power. The destination will consider the one packets received from the best relay to reduce the complexity of the system. We verified BER performance for the proposed protocol through Monte-Carlo simulation over Rayleigh fading plus AWGN.

• Journal of Broadcast Engineering
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• v.23 no.5
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• pp.682-692
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• 2018

In this paper, we propose an ARQ packet error control scheme using multiple threads in delivering massive capacity of multimedia based on MMT(MPEG Media Transport) protocol. On the sending side, each frame that constitutes an image is packetized into MMT packets based on MMT protocol. The header of the packet stores the sequence number of the frames contained in the packet and the time of presentation information. The payload of the packet stores the direct information that comprises the frame. The generated MMT packet is transmitted to the IP network. The receiving side checks if any error has occurred in the received packet. For any identified error, it controls the error through ARQ error control scheme and reconfigure the frame according to the information stored in the header of the received packet. At this point, a multi-threading based transport design is constructed so that each thread takes over a single frame, which increases the transmission efficiency of massive capacity multimedia. The efficiency of the multi-threading transport method is verified by solving the problems that might arise when using a single-thread approach if packets with errors are retransmitted.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11B
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• pp.930-937
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• 2004

In this paper, we analyze the delay performance for a Markovian source transported over a wireless channel with time-varying error characteristics. To improve the reliability of the channel, the end points of the wireless link implement a selective-repeat (SR) ARQ error control protocol. We provide an approximate discrete-time analysis of the end-to-end mean packet delay, which consists of transport and resequencing delays. Numerical results and simulations indicate that our approximate analysis is sufficiently accurate for a wide range of parameter values.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.10
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• pp.674-683
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• 2014

Multi-hop wireless networks has become common phenomenon according to a development of wireless communications and an increase of usage of wireless link. ARQ is one of the common protocols in link layer and can improve a link performance recovering packet loss in wireless link. However, ARQ cannot sufficient to assure a end-to-end performance because ARQ only manages the ARQ's own link. In this paper, we propose a new retransmission persistence for ARQ in multi-hop wireless network to satisfy the end-to-end performance. The proposed scheme can aware a bottleneck link according to the exchange of link information between ARQs and can support the end-to-end performance by managing a retransmission persistence. OPNET simulator is used to evaluate the performance of the proposed scheme and results show that proposed scheme can improve the end-to-end performance with satisfying a requirement of entire wireless section.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.2
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• pp.11-18
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• 1995

Error detection in ARQ(Automatic Repeat Request) protocols is very important in wireless data communication systems. The throughput efficiency of ARQ protocols can be improved by dynamically adapting the protocol packet length so that it approaches the optimum value for throuhput efficiency. In this paper, a simple and novel adaptive packet length allocation method is proposed which transmits the packets with variable length by dyanmically estimating the channel codition. The simulation results show that the average of throughput is improved by 315.4% in the stop-and-wait protocol, 41.4% in the go-back-N protocol and 155.9% in the selective repeat protocol respectively. And the throughput performances of adaptive packet length allocation method approximately approach the theoritically optimal throughput performances.

• 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.