• Journal of Digital Contents Society
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• v.12 no.3
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• pp.347-353
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• 2011

In HIPERLAN/2, the radio channels are assigned by AP(Access Point) that is centrally operated and the MAC protocol is based on TDMA/TDD. Mobile terminal that data transmission is necessary to uplink requests radio resource to AP through RCH channel. The changing number of RCHs in each MAC frame is important because too many RCHs may result in a waste of radio resources and too few RCHs may result in many access collisions and prolong time that connect to AP. Hence the number of RCH should be allocated properly according to traffic. From these point, this paper proposes an scheme that dynamically assigned the number of RCH which is based on the number of success and collision of message in previous MAC frame. To prove efficiency of proposed scheme, lots of simulations are conducted and analyzed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8B
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• pp.757-763
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• 2006

In this paper, a novel multiple access scheme using SMA(Split and Merge Algorithm) is proposed to reduce the accessdelay of wireless MAC protocols. The key idea of the SMA is to dynamically split and merge the contending terminals depending on their traffic loads for effective control of access to the channels. The SMA divides the collided terminals into several sub-groups if a collision occurs and merges the idle terminals of the split sub-groups into their original group. The merge algorithm can be used to resolve collision and split operation can be used to dynamic group management. The simulation results indicate that our algorithm may provide a higher throughput and a lower collision rate than the existing algorithms, especially under heavy traffic loads.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6A
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• pp.351-360
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• 2003

To provide good-quality services of multimedia in wireless mobile networks, QoS for multimedia traffic should be guaranteed. However, since the existing QoS guaranteed schemes are designed for fixed networks, they are inadequate in the wireless network environments. Recently, as the size of cells like micro cell or pico cell becomes smaller. Mobile hosts on micro cellular networks, change their location frequently. It causes many drawbacks such as delayed delivery, packet losses and signaling overheads. Because the existing schemes supporting interoperability between RSVP and Mobile If are designed for macro cell environments. Their uses in micro cellular networks can be restricted. In this paper, we propose the CRSVP(Cellular RSVP Protocol) which supports QoS in micro cellular network environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.5
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• pp.1116-1125
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• 1997

In this paper, the modified UPC(Usage Parameter Control) algorithm is proposed. The proposed UPC algorithm is based on Leakey Bucket algorithm and adds the characteristics of the jumping window algorithm for monitoring the average bit rate. The proposed algorithm let a cell, which is tagged by Leaky Bucket algorithm, pass through the network, if the network does not violate the average bit rate. The measuring method of window mechanism like jumping window. This paper supposes On/Off traffic source model of rthe performance evaluation and analysis of the proposed algorithm. Therefore, as simulation results, the proposed algorithm acquires more reduced results of the cell loss rate and bucket size than the Leaky Bucket algorithm.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.4
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• pp.771-788
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• 1996

A CDMA-based cellular mobile telecommunication system has already been developed and is expected to provide more stable mobile communication services for much more users than traditional analog mobile systems. As a natural course of development, the CDMA mobile system is expected to provide ISDN services in the near future. In this paper, we analyze several traffic control policies for the voice-data integrated traffic in the cellular CDMA system. We first select four admission control policies which take differences in traffic and QOS characteristics between voice and data into account, and then develop modelling and analysis techniques, which can be used directly to analyze the chosen control policies. Our approach is based on so-called threshold model. Numerical computation results obtained under the typical traffic situation are also given. Through these computation results we could tentatively conclude that the cutoff priority policy, which can provide the priority for handoff voice cells while effectively utilizing unused channels, seems to be most effective among the four policies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.3
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• pp.401-408
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• 1998

Recently there comes out various applications on real time control, audio/video conference, medical image and so on. These applications request certain Quality of Service(QoS) to their underlying communication subsystem. In these cases those communication subsystems should provide real time communication service on their QoS request as well as good performance to maintain best effort traffic. In this paper firstly we briefly look over bandwidth, traffic parameters on point to point network secondly we analyze on real time channel and propose design factors in real time channel protocol for multimedia applications.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.3
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• pp.343-350
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• 1999

무선 ATM에서 단말의 이동성을 지원하기 위해서는 핸드오버 기법과 이에 따른 경로 재설정 및 자원재할당, 그리고 서비스 품질(Quality of Service : QoS) 및 트래픽 제어 기술의 구현이 필요하다. 이 문제를 해결하기 위해서 본 논문에서는 무선 ATM기능을 ATM망의 한요소로 보고 기존 ATM 스위치의 Q.2931 프로토콜을 별도의 수정없이 그대로수용하면서 ATM 스위치에 단말의 이동성을 지원하는 별도의 이동성 지원 서버를 두는 방안을 제시하고 구현하였다. 본 논문에서 구현한 이동성 지원 서버는 단말의 이동성 자원을 성공적으로 수행하면서 클러스터 단위로 단말의 이동성 서비스를 지원할 수 있음을 보였다.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.289-300
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• 2005

This paper proposed an analytical framework to compare and model the policy-based network management; centralized and distributed typed model. Policy-based network is introduced in various application fields, and a policy framework can offer different processing performance according to application. Therefore, we evaluated the performance and extensibility of each PBNM model when we apply the policy process to the models. The evaluated measurement metrics are policy provisioning time, traffic occurrence amount, PDP processing rate, and global conflict detection in qualitative simulation. The results show that the suitable structure is required according to the analysis for the careful application characteristics, when PBNM is adopted. The modeling framework presented in this paper is intended to quantify the merits and demerits among the currently suggested PBNM models.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.1
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• pp.88-93
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• 2020

Recently, SDN technology is applied to real communication business, users are getting bigger, and as the amount of data flowing in the network increases, interest in network data flow management is increasing. During this process, it must be ensured that the confidentiality, integrity, availability, and traceability of the data on the network being transmitted. In addition, it is necessary to develop an environment for observing the flow of data in real time on a network required in various fields and visually confirming the control. In this paper, first, Mininet is applied to construct a network topology and various environment attributes. Second, we added OpenDayLight in Mininet environment to develop a simulation environment to visually check and control network traffic flow in network topology.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.310-323
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• 2004

In this paper, we extend the multiple time scale control framework to window-based congestion control, in particular, TCP This is performed by interfacing TCP with a large tine scale control nodule which adjusts the aggressiveness of bandwidth consumption behavior exhibited by TCP as a function of "large time scale" network state. i.e., conformation that exceeds the horizon of the feedback loop as determined by RTT Our contribution is threefold. First, we define a modular extension of TCP-a function call with a simple interface-that applies to various flavors of TCP-e.g., Tahoe, Reno, Vegas and show that it significantly improves performance. Second, we show that multiple time scale TCP endows the underlying feedback control with preactivity by bridging the uncertainty gap associated with reactive controls which is exacerbated by the high delay-bandwidth product in broadband wide area networks. Third, we investigate the influence of three traffic control dimensions-tracking ability, connection duration, and fairness-on performance. Performance evaluation of multiple time scale TCP is facilitated by a simulation bench-mark environment which is based on physical modeling of self-similar traffic.