• Journal of KIISE:Information Networking
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• v.30 no.1
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• pp.134-142
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• 2003

We present an ATM switch architectures based on the multistage interconnection network(MIN) for the efficient multicast traffic control. Many of these applications require multicast connections as well as point-to-point connections. Muiticast connection in which the same message is delivered from a source to arbitrary number of destinations is fundamental in the areas such as teleconferencing, VOD(video on demand), distributed data processing, etc. In designing the multicast ATM switches to support those services, we should consider the fairness(impartiality) and priority control, in addition to the overflow problem, cell processing with large number of copies, and the blocking problem. In particular, the fairness problem which is to distribute the incoming cells to input ports smoothly is occurred when a cell with the large copy number enters upper input port. In this case, the upper input port sends before the lower input port because of the calculating method of running sum, and therefore cell arrived into lower input port Is delayed to next cycle to be sent and transmission delay time becomes longer. In this paper, we propose the cell splitting and group splitting algorithm, and also the fairness scheme on the basis of the nonblocking characteristics for issuing appropriate copy number depending on the number of Input cell in demand. We evaluate the performance of the proposed schemes in terms of the throughput, cell loss rate and cell delay.

• Journal of the Korea Society of Computer and Information
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• v.6 no.1
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• pp.45-50
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• 2001

Congestion may take place in the ATM network because of high-speed cell transmission features, and cell delay and loss also can be caused by unexpected traffic variation. Thus. traffic control mechanisms are needed. One of them to decrease congestion is the cell shaping. This paper proposes a hybrid type cell shaper composed of a Leaky Bucket with token pool, EWMA with time window, and a spacing control buffer. The simulator BONeS with the ON/OFF traffic source model evaluates the performance of the proposed cell shaping method. Simulation results show that the cell shaping concerning the respective source traffics is adapted to and then controlled on the mean bit rate.

• Journal of the Korea Society of Computer and Information
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• v.9 no.3
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• pp.195-200
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• 2004

The change of traffic by the CDV is entered in a condensed form in UUC/NPC, overflowing the buffer of the net and possibly causing its congestion. For this reason this paper proposes the Cell Spacing Scheme. As the Cell Shaping Scheme, two method is proposed ; RAT based on the time in which cells enter the spacer and RDT based on the time in which cells come out from the spacer. This paper proposes the improved spacing sheme in which the departure time of the present cell determines the departure time of the next one, by combining with Leaky Bucket and on the traffic characteristics of ATM network.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.1
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• pp.23-37
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• 1997

In this paper, performance analysis of video traffic shaper for Motion Picture Experts Group (MPEG) video traffic in on ATM network are investigated. Traffic shaping for MPEG video traffic is proposed as a traffic control function in ATM networks. The proposed shaper smoothes video traffics by controling the output rate of the buffer, which is placed in an MPEG source, according to I,B,P frame sequences of MPEG. In performance analysis of an video traffic shaper, a periodic botch arrival model is suggested to describe cell streams in a frame of MPEG video traffic. The queueing model which has periodic independent botch arrival and periodic deterministic service time is used to obtain the cell loss ratio, the mean cell delay, and the measure of smoothing effect. Simulation results are used to validate this queueing model. The cell loss performance of ATM multiplexer is measured by simulation study with real MPEG-1 data. From the viewpoint of traffic load, the cell loss ratio is observed to be considerably high, which is considered to result from the burstiness of MPEG video traffic. As a result, it is shown that the shaping decreases cell loss ratio of multiplexer. The results of this paper can be employed to establish a basic guideline in the implementation of a traffic control scheme and the design of ATM multiplexer for MPEG video traffic.

• KSCI Review
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• v.15 no.1
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• pp.17-23
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• 2007

The change of traffic by the CDV is entered in a condensed form in UPC/NPC, overflowing the buffer of the net and possibly causing its congestion. For this reason this paper proposes the Cell Spacing Scheme. As the Cell Spaing Scheme. two method is proposed; RAT based on the time in which cells enter the spacer and RDT based on the time in which cells come out from the spacer. This Paper Proposes the improved spacing sheme in which the departure time of the present cell determines the departure time of the next one, by combining with Leaky Bucket and using the traffic characteristics of ATM network.

• Journal of the Korea Society of Computer and Information
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• v.7 no.3
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• pp.143-148
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• 2002

Congestion may take place in the ATM network because of high-speed cell transmission features, and cell delay and loss also can be caused by unexpected traffic variation. Thus, traffic control mechanisms are needed. One of them to decrease congestion is the Cell shaping. This paper proposes a hybrid type cell shaper composed of a Leaky Bucket with token pool, Tn with time window, and a spacing control buffer. The simulator BONeS with the ON/OFF traffic source model evaluates the performance of the proposed cell shaping method. Simulation results show that the cell shaping concerning the respective source traffics is adapted to and then controlled on the mean bit rate.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.8
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• pp.1024-1030
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• 1999

IEEE 1149.1 바운다리스캔은 보드 수준에서 고장점검 및 진단을 위한 테스트 설계기술이다. 그러나, 바운다리스캔 제어기의 특성상 테스트 패턴의 주입에서 관측까지 2.5 TCK가 소요되므로, 연결선상의 지연고장을 점검할 수 없다. 본 논문에서는 UpdateDR 신호를 변경하여, 테스트 패턴 주입에서 관측까지 1 TCK가 소요되게 함으로써, 지연고장 점검을 가능하게 하는 기술을 소개한다. 나아가서, 정적인 고장점검을 위한 테스트 패턴을 개선해 지연고장 점검까지 가능하게 하는, N개의 net에 대한 2 log(n+2) 의 새로운 테스트패턴도 제안한다. 설계와 시뮬레이션을 통해 지연고장 점검이 가능함을 확인하였다.Abstract IEEE 1149.1 Boundary-Scan is a testable design technique for the detection and diagnosis of faults on a board. However, since it takes 2.5TCKs to observe data launched from an output boundary scan cell due to inherent characteristics of the TAP controller, it is impossible to test delay defects on the interconnect nets. This paper introduces a new technique that postpones the activation of UpdateDR signal by 1.5 TCKs while complying with IEEE 1149.1 standard. Furthermore we have developed 2 log(n+2) , where N is the number of nets, interconnect test patterns to test delay faults in addition to the static interconnect faults. The validness of our approach is verified through the design and simulation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.4 s.334
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• pp.21-28
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• 2005

SC-FDE (Single Carrier with Frequency-Domain Equalization), one of physical layers of IEEE802.16, is less sensitive to nonlinear power amplifiers than OFDM while its complexity and performance is comparable. The guard interval length in SC-FDE should be greater than the maximal delay spread. While a delay spread is small in most wireless communication environments, a very large delay spread can be possibly encountered in the mountain areas or due to the repeaters. This paper proposes SC-FDE with variable-length guard intervals. In the proposed method the guard interval length can be determined per each cell or per each subscriber stations.

• Journal of Communications and Networks
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• v.13 no.5
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• pp.494-498
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• 2011

Satellite digital multimedia broadcasting (S-DMB) systems use gap fillers (GFs) to provide wireless multimedia services to non-line-of-sight locations. GFs act as repeaters, and S-DMB systems require GF networks in order to guarantee mobile reception. Each GF covers a cell or sector. In order to provide contiguous coverage of an area comprising two or more cells or sectors, multiple GFs are needed. However, when multiple GFs are situated close to each other, interference is likely to occur. As a result, in this study, we have investigated system-level environments for planning the design of interference-free GF networks in S-DMB systems. Our investigations revealed that S-DMB services are unavailable because of quality deterioration caused by interference when the delay attributable to a GF and the satellite signals exceeds ${\pm}$256 chips and the distance between the GF and its reception terminal is greater than 4.6 km. On the basis of this analysis, we conducted a field test that confirmed that the above-mentioned time delay can be controlled in such a way as to ensure high quality S-DMB services.

• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.459-466
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• 1999

I broadband ISDN every packet will show different result if it would be processed according to its usage by the server. That is, normal data won't show big differences if they would be processed at normal speed. But it will improve the quality of service to process some kinds of data - for example real time video or voice type data or some data for a bid to by something through the internet - more fast than the normal type data. solution for this problem was suggested - priority packets. But the analyses of them are under way. Son in this paper a switching system for an output queuing model in a single server was assumed and some packets were given priorities and analysed. And correlation, simulating real life situation, was given too. These packets were analysed through three cases, first packets having no correlation, second packets having only correlation and finally packets having priority three cases, first packets having no correlation, second packets having only correlation and finally packets having priority and correlation. The result showed that correlation doesn't affect the mean delay time and the high priority packets have improved mean delay time regardless of the arrival rate. Those packets were assumed to be fixed-sized like ATM fixed-sized cell and the contention strategy was assumed to be short bus contention method for the output queue, and the mean delay length and the maximum 버퍼 length not to lose any packets were analysed.