Bongkyo Moon

University of London, Londinium, England, United Kingdom

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Publications (9)14.26 Total impact

  • Hoyeon Lee, Bongkyo Moon, A.H. Aghvami
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    ABSTRACT: After acquiring a new Internet protocol (IP) address due to a vertical handover, IP multimedia subsystem (IMS) subscriber has to send session initiation protocol (SIP) messages for registration and session setup to keep an ongoing session. In this paper, we call this registration and session setup delay 'IMS delay.' We show that the IMS delay is unacceptable for supporting real-time applications in vertical handover from Wireless Fidelity (WiFi) to Universal Mobile Telecommunications System (UMTS). To reduce the IMS delay in case of moving to UMTS from WiFi, we propose an enhanced SIP that makes it possible to apply make-before-break handover scheme under IMS. Using the proposed enhanced SIP, SIP messages are sent via WiFi interface before breaking WiFi connection. We define two new headers in SIP and how these new headers work. Numerical results show that the minimum IMS delay with traditional SIP is 0.609936s whilst the maximum IMS delay with enhanced SIP is 11.666ms.
    Next Generation Mobile Applications, Services and Technologies, 2008. NGMAST '08. The Second International Conference on; 10/2008
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    Bongkyo Moon, A.H. Aghvami
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    ABSTRACT: In this paper, we focus on resource reservation protocol (RSVP)-based quality-of-service (QoS) provisioning schemes under Internet protocol (IP) micromobility. We consider QoS provisioning mechanisms for on-going RSVP flows during handoff. First, the rerouting of RSVP branch path at a crossover router (CR) at every handoff event can minimize resource reservation delays and signaling overheads, and in turn the handoff service degradation can be minimized. We show that RSVP branch path rerouting scheme could give a good tradeoff between the resource reservation cost and the link usage. Second, the new RSVP reservation can be made along the branch path toward the CR via a new base station in advance, while the existing reservation path is maintained, and in turn the on-going flow can be kept with the guaranteed QoS. We also show that seamless switching of RSVP branch path could provide the QoS guarantee by adaptively adjusting the pilot signal threshold values. Third, during RSVP resource reservation over wireless link, dynamic resource allocation scheme is used to give a statistical guarantee on the handoff success of on-going flows. We finally obtain the forced termination probability of guaranteed service flows, the average system time of best effort flows by using a transition rate matrix approach.
    IEEE Journal on Selected Areas in Communications 07/2004; · 3.12 Impact Factor
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    Bongkyo Moon, H. Aghvami
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    ABSTRACT: We focus on DiffServ for QoS provisioning in radio access networks (RANs). We first give short explanations of the DiffServ model. We then investigate the problems of DiffServ under IP mobility environments. We also present several DiffServ proposals in IP-based access networks. We finally propose a mobility-aware drop precedence scheme for flows experiencing handover events.
    IEEE Wireless Communications 11/2003; · 3.74 Impact Factor
  • Minkook Kang, Bongkyo Moon, K.H. Aghvami
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    ABSTRACT: Future wireless networks are evolving to provide various real-time multimedia services to mobile users and need an adaptive wireless IP quality of service (QoS) framework. Present radio access networks (RAN) are bandwidth-limited and lack appropriate resource management mechanisms to satisfy fast handoff and provision for QoS, degrading the network performance. We examine bandwidth resource management using the Differentiated Service (DiffServ) mechanism to provision QoS guarantee. Three micro-mobility protocols and two QoS mechanisms are considered. Based on existing solutions, a DiffServ enabled micro-mobility domain is simulated using Network Simulator (NS2) and QoS guarantee is provisioned for each traffic class. DiffServ enabled/nonenabled micro-mobility domain performance comparison during handoff is presented. Furthermore, a dynamic resource allocation scheme is proposed for performance improvements. This work is then an effort to implement a working environment to improve the current challenges supporting both fast handoff and provision of QoS over IP-based RAN.
    Personal Mobile Communications Conference, 2003. 5th European (Conf. Publ. No. 492); 05/2003
  • Bongkyo Moon, A.H. Aghvami
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    ABSTRACT: We propose a wireless resource allocation scheme considering mobility for providing quality of service (QoS) under IT micro mobility domain with differentiated services (DiffServ). In this scheme, each base station provides infinite waiting queue for both assured forwarding (AF) and best effort (BE) handoff flows and guard channels for expedited forwarding (EF) handoff flows. This scheme also allows BE flows to overflow over the region reserved for EF flows with the risk of being preempted by the newly arriving EF flows. If there is no idle channel bandwidth in a new cell after a handoff in heavily crowded area, the EF handoff request is just dropped. Hence, it is required to give a statistical guarantee on the EF handoff success in this wireless mobile environment. The remaining channel bandwidth except for the regions reserved for EF flows in a cell is dedicated to both AF and BE flows. The BE flows preempted by the newly arriving EF flows in a cell are queued, and AF handoff flows has preemptive priority over BE flows existing in dedicated region. We derive the dropping probabilities of both EF and AF flows, and the average system time of BE flows by using a transition rate matrix approach. We also obtain the forced termination probability of EF flow and bandwidth utilization.
    Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE; 12/2002
  • Source
    Bongkyo Moon, H. Aghvami
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    ABSTRACT: We focus on how quality of service (QoS) guarantees can be provided for RSVP flows during handoff events in an IP micromobility network. For this purpose, RSVP message delays and signaling overheads should be minimized, and handoff service disruption should also be minimized. By rerouting the RSVP branch path at a crossover router at every handoff event, and establishing the new RSVP path between the CR and new BS in advance while the existing reservation path is maintained, ongoing RSVP flows can be kept with the guaranteed QoS. We propose the seamless switching of an RSVP branch path for soft handoff, and also show that this scheme could provide QoS guarantee with simulation and examples.
    IEEE Wireless Communications 11/2002; · 3.74 Impact Factor
  • Source
    Bongkyo Moon, A.H. Aghvami
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    ABSTRACT: RSVP (resource reservation protocol) is an attempt to provide a real-time service through the use of virtual circuits in the Internet. It is designed for the integrated services (IntServ) model, and allows Internet real-time applications to reserve resources before they start transmitting data. We consider a cellular system with two-level hierarchy, where RSVP resource reservation is made newly over the two-hop link between the macro-level base station and the mobile host during a handoff. For wireless access networks, we propose a dynamic resource allocation scheme that adapts to variations in handoff attempts, where a macrocell provides bandwidth channels for the GS (guarantee service) handoff flows overflowing from the underlying micro-cells. We derive the average system time of BE (best effort) flows. We also obtain the forced termination probability of GS flow and other performance measures.
    Personal, Indoor and Mobile Radio Communications, 2002. The 13th IEEE International Symposium on; 10/2002
  • Source
    Bongkyo Moon, A H Aghvami
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    ABSTRACT: In this paper, we propose the seamless switching scheme of RSVP (resource ReSerVation Protocol) branch path for soft handoff in IP micro-mobility domain. Typically, in order to minimize the handoff service disruption of RSVP flows, RSVP message delays and signaling overheads should be minimized. We firstly propose the rerouting scheme of RSVP branch path at a crossover router (CR) at every handoff event, and secondly propose the reservation scheme of new RSVP branch path between the CR and new BS in advance while the existing reservation path is maintained. Eventually, we show that this scheme could provide the QoS guarantee for RSVP flows during handoff with simulation and examples.
    10/2002;
  • B. Moon, H. Aghvami
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    ABSTRACT: Currently, the RSVP model, which is efficient resource reservation in the fixed endpoints, becomes invalid under host mobility. We investigate the problems of standard RSVP in providing real-time services in wireless mobile networks. We also observe carefully how to interoperate IntServ services over DiffServ networks, and how to map IntServ QoS parameters into a wireless link. We then identify the advantages and drawbacks of the existing RSVP proposals to support QoS under both micromobility and macromobility. We finally propose a dynamic resource allocation scheme for reducing service disruption of real-time applications due to frequent mobility of a host
    IEEE Communications Magazine 01/2002; · 3.66 Impact Factor

Publication Stats

138 Citations
14.26 Total Impact Points

Institutions

  • 2002–2004
    • University of London
      Londinium, England, United Kingdom
  • 2002–2003
    • King's College London
      • Centre for Telecommunications Research (CTR)
      Londinium, England, United Kingdom