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A Vertical Handoff Decision Algorithm for Heterogeneous Wireless Networks
"... Abstract — One of the major design issues in heterogeneous wireless networks is the support of vertical handoff. Vertical handoff occurs when a mobile terminal switches from one network to another (e.g., from WLAN to CDMA 1xRTT). The objective of this paper is to determine the conditions under which ..."
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Abstract — One of the major design issues in heterogeneous wireless networks is the support of vertical handoff. Vertical handoff occurs when a mobile terminal switches from one network to another (e.g., from WLAN to CDMA 1xRTT). The objective of this paper is to determine the conditions under which vertical handoff should be performed. The problem is formulated as a Markov decision process. A link reward function and a signaling cost function are introduced to capture the tradeoff between the network resources utilized by the connection and the signaling and processing load incurred on the network. A stationary deterministic policy is obtained when the connection termination time is geometrically distributed. Numerical results show good performance of our proposed scheme over two other vertical handoff decision algorithms, namely: SAW (Simple Additive Weighting) and GRA (Grey Relational Analysis). I.
Vertical Handoff Decision Algorithms for Providing Optimized Performance in Heterogeneous Wireless Networks
"... There are currently a large variety of wireless access networks, including the emerging Vehicular Ad-hoc Networks (VANETs). A large variety of applications utilizing these networks will demand features such as real-time, high-availability and even instantaneous high-bandwidth in some cases. Therefo ..."
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There are currently a large variety of wireless access networks, including the emerging Vehicular Ad-hoc Networks (VANETs). A large variety of applications utilizing these networks will demand features such as real-time, high-availability and even instantaneous high-bandwidth in some cases. Therefore, it is imperative for network service providers to make the best possible use of the combined resources of available heterogeneous networks (WLAN, UMTS, VANETs, Wi-MAX, etc.) for connection support. When connections need to migrate between heterogeneous networks for performance and high-availability reasons, then seamless vertical handoff is a necessary first step. In the near future, vehicular and other mobile applications will expect seamless vertical handoff between heterogeneous access networks. With regard to vertical handoff performance, there is a critical need for developing algorithms for connection management and optimal resource allocation for seamless mobility. In this paper, we develop a vertical handoff decision algorithm that enables a wireless access network to not only balance the overall load among all attachment points (e.g., Base Stations (BSs) and Access Points (APs)) but also to maximize the collective battery lifetime of Mobile Nodes (MNs). Moreover, when ad-hoc mode is applied to 3/4G wireless data networks, VANETs and IEEE 802.11 WLANs for more seamless integration of heterogeneous wireless networks, we devise a route selection algorithm to forward data packets to the most appropriate AP in order to maximize the collective battery lifetime as well as maintain load balancing. Results based on a detailed performance evaluation study are also presented here to demonstrate the efficacy of the proposed algorithms.
Takeover: A New Vertical Handover Concept for Net-Generation Heterogeneous Networks",
- Vechicular Technology Conference, 2005 VTC 2005-Spring 2005 IEEE 61st
, 2005
"... Abstract-One of the major challenges for seamless mobility in next-generation heterogeneous networks is vertical handover, which is the process of maintaining a mobile user's active connections as it changes its point of attachment. For seamless vertical handover, we introduce a new concept, T ..."
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Abstract-One of the major challenges for seamless mobility in next-generation heterogeneous networks is vertical handover, which is the process of maintaining a mobile user's active connections as it changes its point of attachment. For seamless vertical handover, we introduce a new concept, Takeover, which enables a neighbor node to process requests of a mobile node. We develop protocol and operation for the takeover and apply it to vertical handover for next-generation heterogeneous networks. The proposed handover scheme using the takeover protocol reduces average handover latency and so enables a fast and seamless handover between two different access technologies. The simulation results show that the takeover-based vertical handover scheme achieves better performances compared with conventional handover schemes, with respect to handover delay, packet loss, and power consumption. I. INTRODUCTION Next-generation communication requires universal wireless access and ubiquitous computing through seamless personal and terminal mobility. One of the major challenges for seamless mobility is vertical handover, which is the process of maintaining a mobile user's active connections as it moves between different types of network. In order to achieve seamless vertical handover in heterogeneous network environments, it is necessary to guarantee service continuity and quality-ofservice (QoS), which means low latency and low packet loss during handover Generally, conventional handover schemes have been proposed by using pre-registration or post-registration method, which can reduce the handover delay because they separate layer 2 (L2) and L3 handovers and perform the L3 handover earlier or later than the L2 handover
A Cross-Layering and Autonomic Approach to Optimized Seamless Handover
"... Abstract — Performing global node mobility requires to support seamless vertical and horizontal handovers between different network providers and technologies. The optimization of the handover processes requires not only continuous network services, but also continuous service performance. In this p ..."
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Abstract — Performing global node mobility requires to support seamless vertical and horizontal handovers between different network providers and technologies. The optimization of the handover processes requires not only continuous network services, but also continuous service performance. In this paper we present a novel design approach based on autonomic components and cross-layer monitoring and control to optimize the performance of the WiOptiMo system, which provides seamless internetwork roaming by handling mobility at the application layer. We also distinguish from past work, in that we pragmatically followed the approach to rely only on existing technologies, deployed protocols and lightweight calculations, such that our system can be straightforwardly implemented as it is on most of the currently available mobile network devices. We report results from some simple real-world experiments showing the benefits of using a cross-layering approach. We also describe a first version of the new WiOptiMo based on the innovative design. Results from preliminary tests in real-world scenarios indicate the effectivness of our pragmatic approach. The system is still under development and testing, and we plan to integrate in it several autonomic components, which are presented and discussed in the paper. 1 I.
DTN based dominating set routing for MANET in heterogeneous wireless networking
- Mobile Networks and Applications
, 2009
"... Abstract In mobile communications, effective inter-networking is mandatory in order to support user roam-ing among various types of wireless networks while maintaining connectivity. In this paper, we propose a super node system architecture to achieve the con-nectivity over interconnected heterogene ..."
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Abstract In mobile communications, effective inter-networking is mandatory in order to support user roam-ing among various types of wireless networks while maintaining connectivity. In this paper, we propose a super node system architecture to achieve the con-nectivity over interconnected heterogeneous wireless access networks, which employs the delay-tolerant net-work (DTN) concept to overcome the problem of po-tential intermittent connections caused by user roaming and ensures message delivery in the presence of a long disconnection period. By introducing the concept of virtual network topology, we present a new rout-ing technique for mobile ad hoc networks (MANETs) within the system architecture, which redefines the dominating-set based routing for the challenged net-work environment. A time based methodology is pre-sented to predict the probability of future contacts between node pairs for constructing the virtual network
Adaptive Channel Selection Through Collaborative Sensing
"... Abstract — Proper channel selection is essential to exploit the benefits of multi-channel systems by distributing conflicting transmissions across non-interfering channels. Critical to channel selection is the channel quality metric. We propose a busy time ratio (BT R) metric that captures channel c ..."
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Abstract — Proper channel selection is essential to exploit the benefits of multi-channel systems by distributing conflicting transmissions across non-interfering channels. Critical to channel selection is the channel quality metric. We propose a busy time ratio (BT R) metric that captures channel contention and user traffic load under a variety of network dynamics. We also propose a distributed collaborative sensing scheme to reduce sensing overhead and energy consumptions. The proposed algorithms can be implemented using conventional 802.11 hardware with single radio interface. The proposed metric can be integrated with routing and channel selection. Experimental results show that the proposed scheme significantly outperforms the existing channel selection methods. Index Terms — Multiple channel, channel selection, available bandwidth, busy time ratio
Article Adaptive Momentum-Based Motion Detection Approach and Its Application on Handoff in Wireless Networks
, 2009
"... sensors ..."
Akhila ―Handover Modeling of Multiple States of Mobile Node in a Five Node Network Model
- International Journal of Computer Applications (IJCA) (0975 – 8887) Volume 111– No.3, February 2015
"... In this work, handover probability, unnecessary handover probability, missing handover probability and wrong decision probability are computed for a five node network model. The four states of mobile node, namely Cooperative state, failed state, selfish state and malicious state are also modeled. Th ..."
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In this work, handover probability, unnecessary handover probability, missing handover probability and wrong decision probability are computed for a five node network model. The four states of mobile node, namely Cooperative state, failed state, selfish state and malicious state are also modeled. The simulation results are presented for a case of bandwidths up to 20. Decision time has been varied from 11ms to 15ms. Finally important conclusions are drawn and future work is defined.
Using Predictive Triggers to Improve Handover Performance in Mixed Networks”,
, 2008
"... Abstract. End-users of multi-radio devices expect ubiquitous connectivity anytime and anywhere across heterogeneous networks. A minimal service disruption time while roaming across networks is key for successful deployments. Today's roaming decisions are reactive and traditionally based on thr ..."
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Abstract. End-users of multi-radio devices expect ubiquitous connectivity anytime and anywhere across heterogeneous networks. A minimal service disruption time while roaming across networks is key for successful deployments. Today's roaming decisions are reactive and traditionally based on thresholds for signal strength, missed beacons, or other properties, leading to undesirable handover delays. In this paper we propose a novel and energy efficient approach to predict when a device needs to take proactive actions to perform either a horizontal or vertical handover. The significant improvements our solution achieved in reducing service discontinuity time are demonstrated by applying our algorithms on WiFi and WiMax networks, in both enterprise and city-wide wireless environments.
An Adaptive Multipath Protocol for Efficient IP Handoff in Mobile Wireless Networks ∗
"... Achieving IP handoff with a short latency and minimal packet loss is essential for mobile devices that roam across IP subnets. Many existing solutions require changes to be made to the network or transport layer, and they tend to suffer from long handoff latency in either soft or hard handoff scenar ..."
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Achieving IP handoff with a short latency and minimal packet loss is essential for mobile devices that roam across IP subnets. Many existing solutions require changes to be made to the network or transport layer, and they tend to suffer from long handoff latency in either soft or hard handoff scenario, or both; and some are difficult to deploy in practice. We propose a new protocol, called the adaptive multipath protocol, to achieve efficient IP handoff. Based on link-layer signal strength measurements, two different schemes are used to handle soft and hard handoff respectively. Seamless IP handoff is achieved by using multiple transport layer connections on top of persistent link-layer connectivity during soft handoff. To achieve low handoff latency during hard handoff, a set of distributed sessions repositories (SRs), which are independent of the end hosts, are employed. Simulation results clearly support our claims. In particular, the latency for hard handoff is found to be as low as 50 % of that of Fast handoff. 1.
