Browsing by Author "Liu, Zong-Hua"

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Design and Analysis of the Gateway Relocation and Admission Control Algorithm in Mobile WiMAX Networks
(2012-01-01)
Liu, Zong-Hua
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Chen, Jyh-Cheng
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資訊工程學系
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Department of Computer Science
The WiMAX Forum has defined a two-tiered mobility management to minimize handover delay and packet loss. However, it leads to another problem: When to perform ASN GW relocation? The standards only define the ASN GW relocation procedures without specifying when the ASN GW relocation should be performed. It is left for vendors and operators to develop their own proprietary solutions. In this paper, we propose an algorithm, which incorporates traditional Admission Control (AC) and Wiener Process (WP)-based prediction algorithms to determine when to carry out ASN GW relocation. We further develop an analytical model to analyze the proposed algorithm. Simulations are also conducted to evaluate the performance of the proposed algorithm. The results show that the proposed algorithm can improve the performance significantly in terms of blocking probability, dropping probability, average serving rate, and average signaling overhead.
Secure Network Mobility (SeNEMO) for Real-Time Applications
(2011-08-01)
Chen, Tuan-Che
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Chen, Jyh-Cheng
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Liu, Zong-Hua
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資訊工程學系
;
Department of Computer Science
The IETF NEtwork MObility (NEMO) working group has considered how to enable an entire network to move from one location to another. Mobile Virtual Private Network (VPN) has been developed to secure mobile user's communication between untrusted external networks and the protected private internal network. However, the IETF's mobile VPN does not address how to support NEMO. In addition, it is not suitable for real-time applications. In this paper, we propose architecture and protocols to support VPN in NEMO, which is called Secure NEMO (SeNEMO). The proposed SeNEMO, based on Session Initiation Protocol (SIP), is specifically designed for real-time applications over VPN. It allows an entire network to move and still maintains session continuity. In addition to analyzing the security vulnerabilities, we also propose analytical models to evaluate the performance of the proposed SeNEMO. The analysis is validated by extensive simulations. The results show that the proposed SeNEMO can reduce signaling cost significantly.