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Mobile IPv6 (MIPv6) has been approved by the IETF as the standardized solution for mobility management in IPv6 network. MIPv6 is a host-based mobility support specification, and it can provide the global mobility support for mobil...
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Mobile IPv6 (MIPv6) has been approved by the IETF as the standardized solution for mobility management in IPv6 network. MIPv6 is a host-based mobility support specification, and it can provide the global mobility support for mobile terminal. However, MIPv6 handover procedure results in a long handover delay. To improve the handover performance, some MIPv6 variants such as Fast Handover for MIPv6 (FMIPv6) and Hierarchical MIPv6 (HMIPv6) were proposed. However, they all require the mobile terminal to support the mobility management protocols. Recently, the Proxy Mobile IPv6 (PMIPv6) was proposed in IETF NETLMM workgroup, which is a network-based localized mobility management and it can provide the mobility support for mobile node without an involvement in the mobility signaling. The previous work about the performance evaluation of PMIPv6 is mainly based on the analysis and lacks of evaluation in a real system. So, in this paper, we study the PMIPv6 and implement it in the WLAN environments. We set up a test-bed to evaluate its performance and compare it with the other mobility specifications including the MIPv6, FMIPv6 and HMIPv6. The results show that the PMIPv6 can improve the handover performance under low-delay networks, as for the wide are networks, it needs to introduce some mechanism like fast handover needs to further improve its performance.
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Recently wireless 3rd generation mobile telecommunication service providers have been showing strong interest in network-based localized mobility management. This could be a prominent way to support IP mobility to mobile nodes, be...
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Recently wireless 3rd generation mobile telecommunication service providers have been showing strong interest in network-based localized mobility management. This could be a prominent way to support IP mobility to mobile nodes, because it requires minimal functionality on the mobile node. However, there is a limited understanding of security provisioning, security infrastructure, low latency handoff, and deployment scenarios, etc. With the fundamental aim low latency handoff in the proxy Mobile IPv6, we introduce a new approach to minimize handoff latency which could eliminate time required for re-authentication by AAA server while the mobile node is roaming across the localized Proxy Mobile IPv6 domains. From a security perspective, this allows mobile access gateways to exchange mobile node's policy profile and ongoing session securely using a variant of the Diffie-Hellman key agreement. To learn its feasibility, security analysis and handoff latency compared to existing handoff schemes are presented. The result shows that latency of the proposed handoff scheme is relatively lower than latency of the handoff scheme across Proxy Mobile IPv6 domains. This provides the confidentiality and integrity of a mobile node's policy profile and ongoing sessions in the exchange phase additionally.
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The diversity of services delivered over wireless channels has increased people desire in ubiquitously accessing these services from their mobile devices. However, an ubiquitous mobile computing environment faces several challenge...
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The diversity of services delivered over wireless channels has increased people desire in ubiquitously accessing these services from their mobile devices. However, an ubiquitous mobile computing environment faces several challenges such as scarce bandwidth, limited energy resources, and frequent disconnection of the server and mobile devices. Caching frequently accessed data is an effective technique to improve the network performance since it reduces the network congestion, the query delay, and the power consumption. When caching is used, maintaining cache consistency becomes a major challenge since data items that are updated on the server should be also updated in the cache of the mobile devices. In this paper we propose a new cache invalidation scheme called Selective Adaptive Sorted (SAS) cache invalidation strategy. The proposed scheme overcomes the false invalidation problem that exists in most of the invalidation strategies found in the literature. The performance of the proposed strategy is evaluated. Results showed that a significant cost reduction can be obtained with SAS when measuring performance metrics such as delay, bandwidth, and energy.
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In this paper, the accepted submissions published on Handheld and Ubiquitous Computing (HUC) and Ubicomp conferences between 1999 and 2007 are reviewed. We classify 244 papers into six distinct categories and analyze the change in...
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In this paper, the accepted submissions published on Handheld and Ubiquitous Computing (HUC) and Ubicomp conferences between 1999 and 2007 are reviewed. We classify 244 papers into six distinct categories and analyze the change in the distribution of the papers in these categories over the period under review. The strongest change trends identified in the analysis are the decrease in the number of application and interaction related papers and the increase in the number of user studies. We recognized three major issues that we think are missing in the reviewed research: internet-related research, research on technology adaptation and acceptance among end users, and reports on the large-scale deployment of ubiquitous systems. Furthermore we describe the state-of-the-art in ubiquitous computing in the sense of design space as defined by Stankiewitz. In this regard the field has evolved from technological prototyping-oriented art towards end user-driven approaches where real world constraints are taken more seriously. A need for future work on user acceptance, interoperability and privacy issues is suggested.
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Mobile IPv6 enables mobile clients to retain its network connections while roaming into foreign networks. However, in a multi-server environment whereby multiple mirror servers are located at different IP networks providing the sa...
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Mobile IPv6 enables mobile clients to retain its network connections while roaming into foreign networks. However, in a multi-server environment whereby multiple mirror servers are located at different IP networks providing the same service, a mobile client consuming a service from a particular server continues consuming the service from the same server after roaming into foreign network, ignoring the existence of other mirror servers that may give higher throughput based on mobile client's latest network location.
In this paper, we propose an active anycast-based server selection model that enables roaming mobile client to detect and access a mirror server that gives better performance based on the mobile client's latest network location. Two schemes are proposed for such performance enhancement, namely: Best Performance Scheme (BPS), and Acceptable Performance Scheme (APS). In BPS, mobile client re-initiates the server selection process whenever it roams into a foreign network. In APS, mobile client re-initiates the server selection process only if the throughput of the current server drops to a dissatisfactory level. Simulation is , performed to evaluate the proposed schemes and its results are presented and discussed.
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With the improvement of miniaturized fabrication and battery technologies, the topic of deploying a wireless sensor network which uses tiny sensors with the abilities of detecting environmental factors and processing data is getti...
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With the improvement of miniaturized fabrication and battery technologies, the topic of deploying a wireless sensor network which uses tiny sensors with the abilities of detecting environmental factors and processing data is getting more and more important for different environments and applications. However, the resource limitation in a sensor brings out an important issue. The challenges for saving energy and thus extending the lifespan of a sensor are conceivable. This paper proposes a protocol involving multi-hops and self-organization of routing paths. The method, using time division with reservation scheduling, reduces energy consumption and prevents packet collisions. The routing decision takes the transmission cost, the battery status and the traffic load into consideration. This yields efficient routings and results in energy savings in sensors. The experimental results show the system's lifespan is extended dramatically and the system is quite robust under different environmental narameters.
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Main concepts to handle in ambient computing applications are hard to integrate at the same time. After studying mid-dlewares handling a part of the challenge, and after studying possiblities of main paradigms in name of CBSE and ...
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Main concepts to handle in ambient computing applications are hard to integrate at the same time. After studying mid-dlewares handling a part of the challenge, and after studying possiblities of main paradigms in name of CBSE and SOA, we present our Service Lightweight Component Architecture (SLCA) model, based on three main paradigms: Web services, enabling entities interoperability, dynamic discovery, and distribution; lightweight component assemblies to create composite Web services, allowing a high dynamic-ity; and finally events, giving applications reactivity and a maximal decoupling between entities, thus enabling an even higher dynamicity. This leads to conciliate both service oriented and event driven approaches in a new way to manage a graph of cooperating services in ubiquitous systems.
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Wireless local area networks (WLANs) have been rapidly developed in recent years for various applications. VoWLAN, which transmits VoIP data over WLANs, shows its amazing attraction and constitutes one of the most flourishing appl...
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Wireless local area networks (WLANs) have been rapidly developed in recent years for various applications. VoWLAN, which transmits VoIP data over WLANs, shows its amazing attraction and constitutes one of the most flourishing applications nowadays in WLANs. How to improve the capacity while providing QoS of VoWLAN is a big concern for network planners. In this paper, we propose and validate an improved Markov analysis model to study the performance of VoWLAN. Based on the developed analytical model, we bring forward a solution that boosts the capacity high enough to support larger number of calls than existing schemes, with fair call quality. The solution comes in two parts: Frame Enqueue Rear-end Aggregation and Device Differentiation Configuration. We demonstrate the performance of the proposed approach through extensive simulations based on ns-2 and Linux-based VoWLAN environment. The experimental results are very promising; the VoIP capacity was improved by 163.7%.
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SIP-NEMO has previously been proposed in the literature as a NEtwork Mobility (NEMO) solution. However, the SIP-NEMO handoff delay has been shown to be more than 320 ms, which is intolerable to real-time services. In this paper, w...
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SIP-NEMO has previously been proposed in the literature as a NEtwork Mobility (NEMO) solution. However, the SIP-NEMO handoff delay has been shown to be more than 320 ms, which is intolerable to real-time services. In this paper, we focus on the SIP-NEMO and aim to reduce the handoff delay of SIP-NEMO.We design soft handoff mechanism for SIP-NEMO and implement a test-bed of SIP-NEMO with soft handoff support. Our experimental results indicate that our SIP-NEMO with soft handoff support can effectively lower down the handoff disruption time compared with SIP-NEMO without soft handoff and MIPv4-NEMO with fast handover. Thus, our proposed soft handoff mechanism for SIP-NEMO can improve the handoff performance to meet the delay requirement of real-time multimedia applications.
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Call Admission Control (CAC) plays a significant role in providing Quality of Service (QoS) in wireless broadband mobile networks. Although much research focuses on modified Mobile IP to get better efficient performance, there are...
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Call Admission Control (CAC) plays a significant role in providing Quality of Service (QoS) in wireless broadband mobile networks. Although much research focuses on modified Mobile IP to get better efficient performance, there are few papers to discuss admission control when considering handover and mobility management. CAC should be introduced to Mobile IP-based network to guarantee the QoS for users. In this paper, we propose a CAC scheme which incorporates multiple traffic types and adjusts the admission threshold dynamically using fuzzy inference system (FIS) to achieve better usage of resources. According to the simulation results, it is evident that these CAC schemes can reduce the probability of the handoff dropping and the cell overload and limit the probability of the new call blocking. The method can provide QoS in Mobile IPv6 networks with few modifications on MAP functionality and slight change in binding update (BU) message formats.
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