• 한국경영과학회지
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• 제24권2호
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• pp.95-108
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• 1999

The CDMA mobile system consists of several subsystems and each subsystem has many processing elements that handle voice messages and control messages for performing CDMA call processing functions through CDMA Interconnection Network(CIN). For assuring a high throughput and a short delay in the CIN, an efficient medium access control protocol should be provided. In this paper, we propose a new access control protocol of CIN for providing real time communications in CDMA mobile system. Also, we evaluate the delay performance of the proposed access control protocol and compare it with that of the existing access control protocol. Through a set of numerical examples, we show that our proposed protocol provides a better delay performance than the existing protocol.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(3)
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• pp.149-152
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• 2000

In the Internet, multimedia data transfer is hard to guarantee the characteristics of the Real-Time because of the Best-Effort of the nature of IP, then additional mechanism is applied to multimedia application for real-time data. In this paper, we introduce the nature of multimedia and the necessary facility for real-time protocol. We propose protocol layer, which has necessary function above mentioned and offer the end-to-end transfer far real-time data. Also, the proposed protocol perform a next low operation: 1) a required information for QoS control by using Feedback mechanism is obtained from sender, 2) divided a transferred packet by delay and loss priority. 3) recognized the low service models, and 4) decided a bandwidth and QoS according to a network state

• Journal of applied mathematics & informatics
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• 제22권1_2호
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• pp.501-515
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• 2006

The IEEE 802.11 protocol is the most mature technology for WLANs(Wireless Local Area Networks). However, as the number of stations increases, the delay and throughput performance of IEEE 802.11 MAC(Medium Access Control) degrades severely. In this paper, we present the comprehensive performance analysis of IEEE 802.11 MAC protocol by investigating the MAC layer packet service time when arrival packet sizes have a general probability distribution. We obtain the discrete probability distribution of the MAC layer service time. By using this, we analyze the system throughput and the MAC layer packet service time of IEEE 802.11 MAC protocol in wireless LAN environment. We take some numerical examples for the system throughput and the mean packet service time for several special distributions of arrival packet sizes.

• 한국음향학회지
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• 제34권6호
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• pp.463-469
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• 2015

본 논문에서는 수중 전파 지연을 고려한 매체 접근 제어 프로토콜을 제안하고 제안하는 프로토콜의 성능을 평가한다. 제안하는 수중 전파 지연을 고려한 매체 접근 제어 프로토콜은 한 슬롯 시간 내에 여러 개의 RTS(Request-To-Send) 프레임들이 싱크 노드에 수신되는 경우에 RTS 프레임들이 겹치지 않게 수신되면 이들을 복원할 수 있다. 본 논문에서는 제안하는 수중 전파 지연을 고려한 매체 접근 제어 프로토콜의 성능 평가를 다양한 환경에서 수행하고 기존의 매체 접근 제어 프로토콜과도 성능을 비교 분석한다.

• 한국경영과학회지
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• 제22권2호
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• pp.99-123
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• 1997

Performance analysis of NTT/BT protocol is investigated, which is a GFC (Generic Flow Control) ptotocol in ATM (Asynchronous Transfer Mode ) network and is based on cyclic reset mechanism. THe mean cell delay time is proposed as a performance measure of NTT/BT protocol. The mean cell delay time is defined as the duration from the instant the cell arrives at the transmission buffer until the cell is fully transmitted. The process of cell transmission can be described as a single server queueing modle with two dependent services. By utilizing this model, mean cell delay time is obtained and sensitivity of the factors such as window size and reset period is also analysed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.118.1-118
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• 2002

Recent trends in internet access to the device network require that information be provided from anywhere in the enterprise. One then needs to integrate both device network protocol and data network protocol to realize Virtual Device Network (VDN). Interoperability between devices and equipments is essential to enhance the quality and the performance of VDN. LonWorks technology is incorporated as device network protocol for interoperability. VDN integrating both device network and data network has varying time delay. Inherent varying time delay of VDN can significantly degrade the reliability of Distributed Control System. This study investigates the transmission characteristics of VDN and s...

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.119.3-119
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• 2001

When building a network-based real-time control system, a network-induced delay time should be surly considered for real time schedulability to be guaranteed. The network delay time on end-to-end communication has been analyzed theoretically and modeled mathematically from many previous works. There also exist any other delay element not considered before. In this paper, the remote feedback control system using the CAN protocol is proposed to control three axes´ manipulator arm and the application layer of CAN is modeled to analyze the delay elements defined by three types of time delay: Software delay time, Controller delay time, and Access delay time, in details. The analyzed results are used as an important component to determine PID gains of the proposed system. The effect of the delay time on the control performance is evaluated by com paring the response characteristics of the control system through simulation.

• 한국시뮬레이션학회논문지
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• 제5권1호
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• pp.81-90
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• 1996

In this paper, we propose a new events ordering mechanism for the optimistic distributed simulation of DEVS models. To simulate DEVS models in a distributed environment, a synchronization protocol is required for correct simulation. Time Warp is the most well-known optimistic synchronization protocol for distributed simulation. However, employing the Time Warp protocol in distributed simulation of DEVS models incurs events ordering problem due to the semantic difference between Time Warp and DEVS, Thus, to resolve such semantic difference, we devise the time-and-priority-stamp and $\varepsilon$ -delay schemes. The proposed schemes can order simultaneous events correctly in Time Warp-based distributed simulation of DEVS models.Time Warp and DEVS, Thus, to resolve such semantic difference, we devise the time-and-priority-stamp and $\varepsilon$ -delay schemes. The proposed schemes can order simultaneous events correctly in Time Warp-based distributed simulation of DEVS models.

• 전자공학회논문지S
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• 제35S권1호
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• pp.1-13
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• 1998

The next generation of wireless network will be problably developed as a mobile communications which will support ATM-based multiMedium traffic. We need to develop an dffective MAC protocol in order to support multimedia traffic having variety of QoS characteristics on wireless neteworks. In this paper, we propose a MAC protocol a MAC protocol where mobile terminals having cells to transmit, request slots to base station through requested slot then the base station analyze parameters from mobile and allocate slots to mobile according to priority. The multimedia slot allocation(MSA) protocol divides multimedias applications into real-time/ variant and non real-time services. Entire slots of the frameare partitioned proportionallyby sizeof bandwidth according to types of services, so that related services can use allocated-slots in priority. The proposed algorithm guarantees real time operation since real-time service share slots allocated for non real-real services. The algorithm whih divides slots of the frame is called as an Algorithm A, otherwise as an Algorithm B. The simulation compares by average delay time and cell loss probability between Algorithm and Algorithm B by increasing number of mobile terminal using the proposed MAC protocol. the simulation result for real-time services shows that average delay time and cell loss probability of Algorithm A is better than those of Algorithm B.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권5호
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• pp.218-225
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• 2001

This paper analyses the performance of network system using the CAN(Controller Area Network) protocol. Given messages are assumed to be scheduled by the DMS(Deadline Monotonic Scheduling) algorithm. The mathematical models for time-delay that can be occurred between CAN nodes are defined. The effectiveness of modeling is shown by comparing the difference of time-delay between simulations and practical experiments. We analyse the results according to the variation of factors, such as the number of nodes, the transmission speed, the message size and the number of aperiodic messages through simulation and confirm the real-time performance of lower priority messages. We also investigate the real-time performance of periodic messages when aperiodic message generates.