• 한국통신학회논문지
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• 제33권1B호
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• pp.17-24
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• 2008

The effect of the variable packet size on the LRD characteristic of the MMPP traffic model is investigated. When we generate packet traffic for the performance evaluation of IP packet network, MMPP model can be used to generate packet interarrival time. And a random length of packet size from a certain distribution can be assigned to each packet. However, there is a possibility that the variable packet size might change the LRD characteristic of the original MMPP model. In this study, we investigate this possibility. For this purpose the 'refined traffic' is defined, where packet arrival time is generated according to the MMPP model and a random packet length from a specific distribution is assigned to each generated packet. Hurst parameter of the refined traffic is estimated and compared with the original Hurst parameter, which is the input parameter of the MMPP model. We also investigate the effect of the packet size distribution on the queueing performance of the MMPP traffic model and the relationship between the Hurst parameter and queueing performance.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.57-60
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• 2001

This paper has studied the WAP packet transmission time, using WTP SAR algorithm. One method that is improved transfer ability, SAR fragmented WTP total message down from upper layer and then packet is transmitted to RLP frame time slot. In this paper, we analysis the transmission time of WAP packet with variable HLP layer size on the CDMA wireless channel for next generation systems as well as PCS, DCS. From the results, we can obtain the WAP packet transmission time and optimal WTP packet size.

• ETRI Journal
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• 제33권3호
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• pp.299-309
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• 2011

Energy consumption is a key issue in body sensor networks (BSNs) since energy-constrained sensors monitor the vital signs of human beings in healthcare applications. In this paper, packet size optimization for BSNs has been analyzed to improve the efficiency of energy consumption. Existing studies on packet size optimization in wireless sensor networks cannot be applied to BSNs because the different operational characteristics of nodes and the channel effects of in-body and on-body propagation cannot be captured. In this paper, automatic repeat request (ARQ), forward error correction (FEC) block codes, and FEC convolutional codes have been analyzed regarding their energy efficiency. The hop-length extension technique has been applied to improve this metric with FEC block codes. The theoretical analysis and the numerical evaluations reveal that exploiting FEC schemes improves the energy efficiency, increases the optimal payload packet size, and extends the hop length for all scenarios for in-body and on-body propagation.

• 산업기술연구
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• 제21권A호
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• pp.59-64
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• 2001

This paper analyzes the performance of the several types of ACL(Asynchronous ConnectionLess) packets used in Bluetooth according to a BER(Bit Error Rate) and a packet length and proposes an optimal packet type and an optimal size of the packet being able to be used under the given BER. This paper proposes how to obtain the optimal packet type and the optimal size of the packet maximizing the performance measure under the given BER. In addition, this paper shows that the optimal type and size of the packet maximizing the throughput are different from those maximizing the mean transmission time. This occurs because the Bluetooth uses not only one type of packet but also various types of packets.

• Journal of information and communication convergence engineering
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• 제4권2호
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• pp.71-74
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• 2006

A basic access method about IEEE 802.11 MAC layer protocol using IEEE 802.11 wireless LANs is the DCF thatis based on the CSMA/CA. But, cause of IEEE 802.11 MAC layer uses original backoff algorithm (exponential backoff method), when collision occurred, the size of contention windows increases the double size Also, a time of packet transmission delay increases and efficienty is decreased by original backoff scheme. In this paper, we have analyzed TCP packet transmission time of IEEE 802.11 MAC DCF protocol for wireless LANs a proposed enhanced backoff algorithm. It is considered the transmission time of transmission control protocol (TCP) packet on the orthogonal frequency division multiplexing (OFDM) in additive white gaussian noise (A WGN) and Rician fading channel. From the results, a proposed enhanced backoff algorithm produces a better performance improvement than an original backoff in wireless LAN environment. Also, in OFDM/quadrature phase shift keying channel (QPSK), we can achieve that the transmission time in wireless channel decreases as the TCP packet size increases and based on the data collected, we can infer the correlation between packet size and the transmission time, allowing for an inference of the optimal packet size in the TCP layer.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.530-533
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• 2006

Recently, a basic access method about IEEE 802.11 MAC layer protocol using IEEE 802.11 wireless LANs is the DCF thatis based on the CSMA/CA. But, cause of IEEE 802.11 MAC layer uses original backoff algorithm (exponential backoff method), when collision occurred, the size of contention windows increases the double size. Also, a time of packet transmission delay increases and efficiency is decreased by original backoff scheme. In this paper, we have analyzed TCP packet transmission time of IEEE 802.11 MAC DCF protocol for wireless LANs a proposed enhanced backoff algorithm. It is considered the transmission time of transmission control protocol (TCP) packet on the orthogonal frequency division multiplexing (OFDM) in additive white gaussian noise (AWGN) and Rician fading channel. From the results, a proposed enhanced backoff algorithm produces a better performance improvement than an original backoff in wireless LAN environment. Also, in OFDM/quadrature phase shift keying channel (QPSK), we can achieve that the transmission time in wireless channel decreases as the TCP packet size increases and based on the data collected, we can infer the correlation between packet size and the transmission time, allowing for an inference of the optimal packet size in the TCP layer.

• 대한전자공학회논문지TC
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• 제40권9호
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• pp.373-383
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• 2003

본 논문에서는 다양한 서비스가 복합적으로 운용되고 있는 인터넷 망에서PCM 및 ADPCM으로 압축된 음성 데이터를 전송할 경우, 패킷 크기와 한계 지연시간의 변화가 수신측의 음질에 미치는 영향을 분석하고 주어진 한계 지연시간에 대하여 최고의 음질을 제공하기 위한 전송 패킷의 크기에 대하여 논한다. 결과를 얻기 위한 실험은 공중 인터넷 망을 통하여 연결된 두 대의 PC 상에서 이루어졌다. 송신측은 마이크로부터의 음성신호를 PCM 및 ADPCM으로 부호화하고 이를 UDP 패킷을 이용하여 전송하였으며, 수신 측에서는 망에서 발생하는 전송 지연 및 패킷 손실 등을 거친 패킷이 음성신호로 재생된다. 음질 평가를 위하여 송수신 음성 데이터를 수집하여 오프라인에서 비교하며, 알고리즘으로는 객관성을 유지하기 위하여 MNB 방법을 이용하였다. 실험 결과에 의하면, 40Kbps, 32Kbps, 16Kbps의 ADPCM으로 압축된 음성의 전송에서 한계 전송 지연을 100ms로 하였을 경우 음질 열화를 최소화하기 위하여는 패킷 크기의 하한이 각각 300, 400, 500바이트, 패킷 크기의 상한은 공히 1200바이트인 것이 요구된다.

• Management Science and Financial Engineering
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• 제4권2호
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• pp.43-58
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• 1998

Packet switch is a key component in high speed digital networks. This paper investigates congestion phenomena in the packet switching with input buffers. For large value of switch size N, mathematical models have been developed to analyze asymptotic maximum switch throughput under nonuniform traffic. Simulation study has also been done for small values of finite N. The rapid convergence of the switch performance with finite switch size to asymptotic solutions implies that asymptotic analytical solutions approximate very closely to maximum throughputs for reasonably large but finite N. Numerical examples show that non-uniformity in traffic pattern could result in serious degradation in packet switch performance, while the maximum switch throughput is 0.586 when the traffic load is uniform over the output trunks. Window scheduling policy seems to work only when the traffic is relatively uniformly distributed. As traffic non-uniformity increases, the effect of window size on throughput is getting mediocre.

• Journal of Communications and Networks
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• 제4권2호
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• pp.108-117
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• 2002

TCP, which was developed on the basis of wired links, supposes that packet losses are caused by network congestion. In a wireless network, however, packet losses due to data corruption occur frequently. Since TCP does not distinguish loss types, it applies its congestion control mechanism to non-congestion losses as well as congestion losses. As a result, the throughput of TCP is degraded. To solve this problem of TCP over wireless links, previous researches, such as split-connection and end-to-end schemes, tried to distinguish the loss types and applied the congestion control to only congestion losses; yet they do nothing for non-congestion losses. We propose a novel transport protocol for wireless networks. The protocol called VS-TCP (Variable Segment size Transmission Control Protocol) has a reaction mechanism for a non-congestion loss. VS-TCP varies a segment size according to a non-congestion loss rate, and therefore enhances the performance. If packet losses due to data corruption occur frequently, VS-TCP decreases a segment size in order to reduce both the retransmission overhead and packet corruption probability. If packets are rarely lost, it increases the size so as to lower the header overhead. Via simulations, we compared VS-TCP and other schemes. Our results show that the segment-size variation mechanism of VS-TCP achieves a substantial performance enhancement.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
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• pp.317-320
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• 2004

In this paper, it is analyzed a performance improvement of ACL Packet using turbo code scheme in bluetooth system. In order for segment to improve the transfer capability, the transmission of messages have been simulated using a fragmentation that begins with the total package and incremental fragmentation for each layer using the TCP to define the resultant packet size and the level of fragmentation for each proceeding layer. This turbo code scheme decreases transmission time of L2CAP baseband packets by sending packets. From the results, we were able to obtain packet transmission time, optimal TCP packet size, ACL(DM packet) in AWGN.