• Journal of KIISE:Information Networking
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• v.35 no.4
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• pp.355-366
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• 2008

This paper proposes a mobile SCTP (mSCTP) handover scheme for vertical handover between 3G wireless and WiBro networks. To evaluate the proposed mSCTP vertical handover scheme, we implement the mSCTP handover supporting system over Linux platform in which the movement of a mobile node is automatically detected and the mSCTP vertical handover is performed by the mobile node. We analyze and compare the performance of mSCTP handover and Mobile IP handover over the preconfigured testbed. From the numerical results, we can see that the handover latency of mSCTP could be much more reduced, compared to the Mobile IP handover, if the mobile node would sojourn long enough in the overlapping region between the two heterogeneous networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.3
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• pp.266-284
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• 2009

The challenges of rapidly growing numbers of mobile nodes in IPv6-based networks are being faced by mobile computing researchers worldwide. Recently, IETF has standardized Mobile IPv6 and Fast Handover for Mobile IPv6(FMIPv6) for supporting IPv6 mobility. Even though existing literatures have asserted that FMIPv6 generally improves MIPv6 in terms of handover speed, they did not carefully consider the details of the whole handover procedures. Therefore, in conventional protocols, the handover process reveals numerous problems manifested by a time-consuming network layer based movement detection and latency in configuring a new care of address with confirmation. In this article, we study the impact of the address configuration and confirmation procedure on the IP handover latency. To mitigate such effects, we propose a new scheme which can reduce the latency taken by the movement detection, address configuration and confirmation from the whole handover latency. Furthermore, a mathematical analysis is provided to show the benefits of our scheme. In the analysis, various parameters are used to compare our scheme with the current procedures, while our approach is focused on the reduction of handover latency. Finally, we demonstrate total handover scenarios for the proposed techniques and discussed the major factors which contribute to the handover latency.

• Journal of Communications and Networks
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• v.14 no.5
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• pp.578-587
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• 2012

One of the key elements in the emerging, packet-based long term evolution (LTE) cellular systems is the deployment of multiple femtocells for the improvement of coverage and data rate. However, arbitrary overlaps in the coverage of these femtocells make the handover operation more complex and challenging. As the existing handover strategy of LTE systems considers only carrier to interference plus noise ratio (CINR), it often suffers from resource constraints in the target femtocell, thereby leading to handover failure. In this paper, we propose a new efficient, multi-objective handover solution for LTE cellular systems. The proposed solution considers multiple parameters like signal strength and available bandwidth in the selection of the optimal target cell. This results in a significant increase in the handover success rate, thereby reducing the blocking of handover and new sessions. The overall handover process is modeled and analyzed by a three-dimensional Markov chain. The analytical results for the major performance metrics closely resemble the simulation results. The simulation results show that the proposed multi-objective handover offers considerable improvement in the session blocking rates, session queuing delay, handover latency, and goodput during handover.

• Journal of Information Technology Services
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• v.8 no.1
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• pp.165-177
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• 2009

This paper reviews diverse IP mobility and fast handover mechanisms for seamless Internet services. Especially, fast handover mechanisms for the Proxy Mobile IPv6( PMIPv6) are categorized according to their approaches. Then, a new fast handover PMIPv6(FH-PMIPv6) mechanism is proposed using only L3 signaling message exchange. In the proposed FH-PMIPv6 mechanism, only local mobility anchor(LMA) exchanges L3 signaling messages with mobility access gateways(MAGs) for the fast handover operation. That is, inter-MAG signalling messages are not required for the fast handover operation. Therefore, unlike existing fast handover mechanisms, two relevant neighbouring MAGs need not set up the security association(SA) to protect fast handover related signaling messages and share SA related information. Moreover, the L3 triggering message is defined newly by standard ICMPv6 to trigger promptly the proposed mechanism. Analysis and comparison of the handover latency are performed for the proposed mechanism and existing mechanisms, which shows that the proposed FH-PMIPv6 mechanism has the favorable performance.

• Journal of Information Processing Systems
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• v.7 no.4
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• pp.627-634
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• 2011

This paper addresses the Proxy Mobile IPv6 (PMIP) handover using bicasting in mobile/wireless networks. The bicasting scheme can be used to support the PMIP handover, which tends to waste the network resources of wireless links and incurs data losses during handover. We propose an enhanced scheme of PMIP handover, called the partial bicasting with buffering for PMIP (PBB-PMIP). In the PBB-PMIP handover, the bicasting is performed in the "partial" region between the Local Mobility Anchor (LMA) and the Mobile Access Gateway (MAG), when a mobile node is in the handover area. The data packets are buffered at the new MAG during handover to reduce data losses and are then forwarded to mobile nodes after handover. By ns-2 simulations, the proposed PBB-PMIP scheme is compared with the existing schemes of PMIP and PMIP with bicasting. The proposed scheme can benefit from the reduction of handover delay and packet loss, and the effective use of the network resources of wireless links, as compared to the existing handover schemes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1256-1262
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• 2008

In mobile broadcasting networks, handover is an important issue to support seamless mobility. DVB-H(Digital Video Broadcasting for Handheld) standard was developed to enhance mobile features for DVB-T(Digital Video Broadcasting -Terrestrial) standard. This paper proposes new approaches for improving handover performance in the DVB-H networks. The proposed handover schemes are targeted to two different DVB-H receivers: One is for the receivers equipped with GPS devices. The other is for ones without GPS support. The first handover approach modifies the cell description table (CDT) proposed in the literature [1]. The second proposes a novel estimation technique of predefined handover region based on a new handover map table (HMT). This new handover approach estimates a predefined handover region with the measured RSSI(Received Signal Strength Indication) signal patterns. Using proposed handover algorithm, we can reduce time and power consumption. Through the computer simulations, we evaluate the performance of handover algorithm.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.397-399
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• 2005

Handover is one of the most important factors that may degrade the performance of TCP connections and real-time applications in wireless data networks. We proposed a seamless handover with Motion Prediction in IEEE 802.16e-based broadband wireless access networks. By intergrating MAC and network layer handovers efficiently, this scheme minimizes the handover delay and eliminates packet losses during handover Simulations show that this scheme achieves loss-free packet delivery without packet duplication and increases TCP throughput significantly.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.509-512
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• 2003

본 논문은 무선랜 환경에서 Mobile IPv6 Node가 이동 시에 발생하는 Handover Latency 를 줄이기 위한 새로운 알고리즘을 제안한다. 현재 Mobile IPv6 Fast Handover Protocol 은 Layer2 에서의 Handover 의 도움을 전제로 하기 때문에 실제 구현상에서 Real-time 이나Delay 에 민감한 Application 에 적용하기 어렵다. 이 문제를 해결하기 위해 무선랜에서 사용하는 Beacon 신호를 이용한 Dominant NAR 알고리즘을 적용하여 MIPv6 Fast Handover 과정을 선 처리하여 Handover Latency를 줄이고자 한다.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1463-1466
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• 2002

This paper suggests the effective channel assignment scheme for mobility prediction handover. For maintaining required quality of service (QoS) during handover, there are handover algorithms these reserve the channel where the movement is predicted. But channel assignment schemes these have been studied are not considered mobility prediction handover. This paper suggests the channel assignment scheme that considers mobility predicted handover. The suggested algorithm maintains dropping probability of handover calls, decreases blocking probability of new calls and increases channel utilization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8B
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• pp.1129-1140
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• 2010

Wireless mesh networks have been widely studied as the next generation technology to solve the problems of conventional wireless networks. Particularly, Mobile WiMAX based wireless mesh networks are noticed due to many advantages. Mobile WiMAX standard provides two kinds of layer-3 handover schemes: Mobile IP and Proxy Mobile IP based handover schemes. MIP based handover scheme has a problem in that it incurs the long handover latency because mobile nodes generate a lot of handover messages. On the other hand, PMIP based handover scheme decreases the handover latency by reducing the number of handover messages, because mobile nodes do not participate in handover procedure. Therefore, layer-3 handover for Mobile WiMAX should be designed based on PMIP. However, conventional PMIP based handover still has latency overhead, because of many message exchanges between PBU and PBA after completing the layer-2 handover. Hence, in this paper, we propose a fast layer-3 handover scheme that achieves the lower handover latency for Mobile WiMAX based wireless mesh networks. Proposed scheme has advantages in terms of handover latency. Simulation results show that proposed scheme achieves low handover latency during the layer-3 handover.