• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2542-2544
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• 2000

In this paper, CAN(Controller Area Network)is used to solve the wire harness problem in the outside mirror of automobile which has a lot of functions in narrow space. If the number of wires is reduced, it has benefits of lower product cost and maintenance. CAN was originally developed by the German company Robert Bosch for use in the car industry to provide a cost-effective communications bus for in car electronics and as alternative to expensive and cumbersome wiring looms. CAN controller is a serial communication protocol which efficiently supports distributed real-time control with a very high level of security. The communication between master CAN controller and slave CAN controller is realized and controller's performance is tested by experiment.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.6
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• pp.632-638
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• 1997

The growing number of electronic components used in automobiles has given rise to problems concerning the increasing number, size and weight of the wiring harnesses. As an approach to resolve these problems, multiplexed wiring systems using automotive communication protocol such as Controller Area Network(CAN), Advanced PALMNET and J1850 have been developed by many automobile companies. In order to compare these protocols quantitatively, this paper presents the performance evaluation of CAN and Advanced PALMNET via discrete event simulation. Through numerous simulation experiments, several important quantitative performance factors such as the probability of a transmission failure, average system delay(data latency), and throughput have been evaluated.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.7
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• pp.6-13
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• 1998

To constoruct a multi-channel system like Optical Frequency Division Multiplexing (OFDM) with the vast amount of transmission capability, a frequency stabilization is essential technique for getting narrower channel spacing and for minimizing fluctuation of oscillation frquency of each channel. This paper proposes a novel multi-channel optical frequency stabilization scheme that uses wavelength crossover properties of a Arrayed Waveguide Grating(AWG). The proposed scheme includes an effective control algorithm that carries out frequency stabilization of all channels through a simple control circuit, simulaneously. And also, a design method of AWG is included which has higher resolutio in consideration of system loss.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.05a
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• pp.132-137
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• 1998

In this paper, conventional STM(Synchronous Transfer Mode) supports another traffics by using idle channels Proposed mobile terminals are distributed independently at the BSA(Basic Service Area). So, MAC(Medium Access Control) specified on the wireless ATM networks, which is managing statistics multiplexing functions, idle channel's utilization is maximized and multimedia service characteristic for conventional wired networks based fixed assignment scheme(connection-oriented) and random assignment scheme(connectionless) improving on dynamic reservation based MAC protocol.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1405-1412
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• 2000

In this paper, we propose an efficient dynamic wavelength assignment algorithm in distributed WDM (Wavelength-Division Multiplexing) networks without wavelength conversion. The algorithm tries to assign a locally-most-used wavelength distributedly on a fixed routing path. We first formulate our algorithm by using the concept of a sample space which consists of optical fibers connected to nodes on a routing path of a lightpath to be assigned a wavelength. In particular, we analyze the blocking performance mathematically as compared with that of the most-used (MU) wavelength assignment algorithm previously proposed for WDM networks under centralized control. We also obtain numerical results by simulation on the blocking performance of other centralized/distributed wavelength assignment algorithms as well as our algorithm using the M/M/c/c dynamic traffic model. Consequently, we show that analytical results match simulation results and that our algorithm is efficient in distributed WDM networks in terms of blocking performance, control traffic overhead and computation complexity.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.346-350
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• 2008

In this paper, we analyze the performance of a reliable, scalable, and cost-effective switchless wavelength division multiplexing (WDM) network based on an arrayed waveguide grating (AWG). The network efficiency is significantly increased by spatially reusing wavelengths and exploiting multiple free spectral ranges (FSRs) of the AWG employed in the architecture. We have analyzed the performance of this architecture by simulating in $Optsim^{TM}$ with a control channel which exploits the broadband light source, i.e., an LED. The data was successfully transmitted to a distance of 30 km without using any EDFA's in the network, with a reasonable BER of $4.0530{\times}10^{-14}$. We have analyzed the performance of this architecture with a control channel which exploits the broadband light source, i.e., an LED, by simulating in $Optsim^{TM}$.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.5
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• pp.267-273
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• 2012

The short-range communication module was developed in this paper which is suitable for the point-to-multipoint circumstances of 40 terminals communicating frequently in about 50 meters. The media access control layer of this communication module using asynchronous time-division multiplexing provides a fast and robust performance even in the worst case of simultaneous transmission events, and low packet error rate was measured a in LOS (Line-of-sight) circumstance by adding the function of acknowledge response to media access control layer. The difference test was carried out in order to measure the performance of point-to-multipoint communication. Two communication modules are respectively measured and graphed in 10 branches to 40 branches. The communication module developed in this paper showed a faster performance than the commercial Zigbee module in the specific case presented in this paper. Especially, in over 20 branches showed wide differences of the transmission speed. This results is caused by more network overhead of Zigbee whose wider applications needs the network layer and applicaiton layer besides media access control layer. Also, the asynchronous time-division multiplexing proposed in this paper are more suitable than CSMA-CA of Zigbee module when a lot of module ought to be frequently communicated in small area.

• Journal of the Korea Society of Computer and Information
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• v.5 no.4
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• pp.82-89
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• 2000

This study analyzes the cell loss probability of an ATM multiplexer with real time and non-real time bursty traffics. It is assumed that an ATM multiplexer with loss priority control for the analysis. The loss priority control uses the CLP Reld of cell header. For easy analysis and less computation. the multiplexed traffic of the ATM multiplexer was modeled by the MMDP. The ATM multiplexer is simulated by the MMDP/MMDP/l/K queueing system. From the above results, The connection admission of an ATM multiplexer with loss priority control is determined by the cell loss probability with low priority as well as the size of threshold buffer. Therefore, to increase the statistical multiplexing gain it will be good to utilize the loss priority control in order.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.9
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• pp.2027-2034
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• 1997

Frame relay is a fast packet switching technology that performs relaying and multiplexing frames with variable lengths over a wide area link at the T1 or E1 speed, by elminating error and flow control in the network. In frame relay networks, congestion control is typically performed through the rate enforcement with a discard eligibility (DE) bit, and the explicit negative feedback meachanisms using explicit congetion notification bits. In this paper, we consider the congestiong control scheme using the rate enforcement mechanism with DE bit for frame relay network. Assuming that each frame with exponentially distributed length arrives according to the Poission fashion, we can treat the frame relay switch as an M/M/1/K priority queueing system with pushout basis. We analyze and present the blocking probabilities and waiting time distributions of frames.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1402-1409
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• 2007

In this paper, we propose various types of AGC algorithms for implementing the OFDM communication systems. For the high-speed packet transmission, in this paper, we assume the OFDM system with relatively long and repeated preambles. We propose the maximum sample value counter for counting the number of maximum sample. In the maximum sample value counter, we use the buffer for the digital signal buffering. Finally, the counting value of the maximum sample value counter controls the gain control signal generator by using gain control table automatically.