• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1B
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• pp.1-12
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• 2002

In the multimedia CDMA mobile communication service, it is required to support various applications, such as voice, video, file transfer, e-mail, and Internet access, with guaranteed QoS. In the mixed traffic environment ,which consists of voice, stream data, and packet data, we analyze the network where preemptive priority is granted to delay-intolerant voice service and a buffer is offered to delay-tolerant stream data service. And, for best-effort packet data service, the access control by transmission permission probability is applied to obtain prominent throughput. To analyze the multimedia CDMA mobile communication system, we build a 2-dimensional markov chain model about prioritized-voice and stream data services and accomplish numerical analysis in combination with packet data traffic based on residual capacity equation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8B
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• pp.1150-1158
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• 2010

At present multimedia service composed of voice, data, and video service is prevalent in the Internet. As such, wide-scale penetration of Internet service imposes tremendous pressure to the network infrastructure such as the media servers and links as well as the nodes. In addition, users from a large-scale population require broad bandwidth and high level of QoS. This requires a network with reliable and scalable services to customers, which also necessitates a realistic method for the design of the a media server. In this work, we explore the influence of user's behavior about delay on the performance of media server that takes into account the system and user attributes in a realistic manner. By incorporating user's behavior about the delay-sensitivity, we present an analytic framework for the evaluation of the performance of the media server, via which we illustrate a meaningful intuition in the provision of Internet multimedia service.

• Journal of Information Processing Systems
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• v.2 no.2
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• pp.88-94
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• 2006

In wireless cellular networks, previous researches on admission control policies and resource allocation algorithm considered the QoS (Quality of Service) in terms of CDP (Call Dropping Probability) and CBP (Call Blocking Probability). However, since the QoS was considered only within a predetermined cell capacity, the results indicated a serious overload problem of systems not guaranteeing both CDP and CBP constraints, especially in the hotspot cell. That is why a close interrelationship between CDP, CBP and cell capacity exists. Thus, it is indispensable to consider optimal cell capacity guaranteeing multiple QoS (CDP and CBP) at the time of initial cell planning for networks deployment. In this paper, we will suggest a distributed determination scheme of optimal cell capacity guaranteeing both CDP and CBP from a long-term perspective for initial cell planning. The cell-provisioning scheme is performed by using both the two-dimensional continuous-time Markov chain and an iterative method called the Gauss-Seidel method. Finally, numerical and simulation results will demonstrate that our scheme successfully determines an optimal cell capacity guaranteeing both CDP and CBP constraints for initial cell planning.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.178-191
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• 2005

Fourth-generation (4G) wireless networks will be the IP-based cellular networks integrating Internet with the existing cellular networks. Two important issues should be concerned in the IP-based cellular networks, IP mobility, and quality-of-service (QoS) guarantees. In this paper, we proposed two mechanisms to solve the problems with IP mobility and RSVP-based QoS provisioning. First, virtual-IP (VIP) allocation scheme in areas with a large rate of handoff can minimize the wireless signaling overhead due to IP mobility. The access routers (ARs) create dynamically the VIP zone by using the measured handoff rate derived from the history of the handoff into neighboring ARs. We show that VIP allocation scheme reduces the binding update messages in the wireless link than hierarchical mobile IPv6. Second, the new advance resource reservation protocol called proportional aggregate RSVP (PA-RSVP) can minimize waste of bandwidth and soft state refresh overhead due to IP mobility. It allocates the bandwidth in advance between the mobility anchor point and neighboring ARs using proportional aggregate reservation. We also show that PA-RSVP provides an improved performance over existing protocols.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.441-441
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• 2004

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.118-118
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• 2004

• Annual Conference of KIPS
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• 2011.11a
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• pp.629-632
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• 2011

최근 현재 인터넷이 가지는 한계를 극복하기 위해 전세계적으로 연구가 되고 있는 미래인터넷 테스트베드 분야에서 QoS(Quality of Service)에 대한 요구가 계속 증가되고 있다. 본 논문에서는 시뮬레이션을 통한 검증과 실용성은 한계와 확장성의 문제가 있기 때문에, 기존 네트워크의 정상적인 서비스를 간섭하지 않고 새로운 네트워킹 기술을 실험할 수 있고, 가장 각광 받고 있는 OpenFlow를 이용하여 실제 상용 스위치인 Pronto 3290을 기반으로 한 테스트 베드를 구성하였다. 구성한 테스트 베드를 통하여 패킷 정보에 따라 Path를 사용자 요구에 맞게 변경, 삭제, 생성 할 수 있는 QoS 메커니즘을 설계하고 사용자가 사용하기 편하도록 웹 기반의 인터페이스를 구현을 통하여 검증할 것이다.

• Annual Conference of KIPS
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• 2015.10a
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• pp.387-389
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• 2015

IEEE 802.11e EDCA(Enhanced Distributed Channel Access)는 4개의 AC(Access Category)를 이용하여 트래픽에 따른 우선순위를 부여하고 QoS(Quality of Service)를 제공하기 위해 표준화되었다. EDCA는 이진 백오프 알고리즘을 갖는 CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance) 방법을 이용한다. EDCA에서 패킷 전송에 실패할 경우 경쟁 윈도우 값은 두 배씩 증가 되고, 성공할 경우에는 최소 경쟁 윈도우 값으로 초기화된다. 따라서 경쟁 윈도우 값이 최적의 값을 유지하지 못해 많은 패킷 충돌을 야기하여 네트워크 성능을 감소시킨다. 이 문제를 해결하기 위해 기존에 제안된 논문에서는 패킷 전송 성공 후 경쟁 윈도우 값을 최소 경쟁 윈도우 값이 아닌 채널 혼잡 정도에 따라 계산된 값으로 설정한다. 그러나 이 방법은 트래픽 종류와 상관없이 같은 방법으로 동작하기 때문에 트래픽 종류에 따른 차별적 QoS를 보장하지 않는다. 또한 계산된 경쟁 윈도우 값은 현재 값에 비해 상대적으로 낮은 값을 갖기 때문에 여전히 높은 충돌율을 갖는다. 본 논문에서는 이 문제를 해결하기 위해 새로운 프로토콜을 제안한다. 제안된 방법에서는 네트워크의 혼잡 정도를 잘 반영하기 위한 새로운 경쟁 윈도우 계산 알고리즘을 제시한다. 또한 제안된 알고리즘은 트래픽 종류에 따른 QoS 보장을 위해 트래픽 종류에 따른 차별화 파라미터를 이용한다.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.54.5-54
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• 2002

1. Introduction II. Internet Telephony III. Proposed method for quality of service IV. Simulation V. Conclusion

• Journal of Digital Convergence
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• v.15 no.4
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• pp.259-266
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• 2017

The massive traffic interferences in the wireless home IoT provides the reason for packet losses, and it degrades the QoS (Quality of Service) and throughput on the home network. This paper propose a new adaptive traffic interference control system, ATICS, for enhancing QoS and throughput for IoT services as detecting a traffic process and non-traffic process in the wireless home network. The proposed system control the traffic interferences as distinguishing the short-term traffic process and long-term traffic process by traffic characteristics in wireless home networks. The simulation results shows that the proposed scheme have more efficient traffic control performance than the other schemes.