928 research outputs found
An Overview of Vertical Handoff Decision Algorithms in NGWNs and a new Scheme for Providing Optimized Performance in Heterogeneous Wireless Networks
Because the increasingly development and use of wireless networks and mobile technologies, was implemented the idea that users of mobile terminals must have access in different wireless networks simultaneously. Therefore one of the main interest points of Next Generation Wireless Networks (NGWNs), refers to the ability to support wireless network access equipment to ensure a high rate of services between different wireless networks. To solve these problems it was necessary to have decision algorithms to decide for each user of mobile terminal, which is the best network at some point, for a service or a specific application that the user needs. Therefore to make these things, different algorithms use the vertical handoff technique. Below are presented a series of algorithms based on vertical handoff technique with a classification of the different existing vertical handoff decision strategies, which tries to solve these issues of wireless network selection at a given time for a specific application of an user. Based on our synthesis on vertical handoff decision strategies given below, we build our strategy based on solutions presented below, taking the most interesting aspect of each one.Vertical Handoff, Genetic Algorithms, Fuzzy Logic, Neural Networks, AHP
A cross-layer mobility management framework for next-generation wireless roaming
Word processed copy.Includes bibliographical references (leaves 62-64).This thesis proposes a mobility management framework that aims to provide a framework for advanced mobility algorithms that allows the challenges of next-generation roaming to be met. The framework features tools that gather context and content information, guarantee low-level QoS, provide security, and offer link and handoff management. The framework aims to be scalable and reliable for all-IP heterogeneous wireless networks whilst conforming to 4G service requirements
Fuzzy-logic framework for future dynamic cellular systems
There is a growing need to develop more robust and energy-efficient network architectures to cope with ever increasing traffic and energy demands. The aim is also to achieve energy-efficient adaptive cellular system architecture capable of delivering a high quality of service (QoS) whilst optimising energy consumption. To gain significant energy savings, new dynamic architectures will allow future systems to achieve energy saving whilst maintaining QoS at different levels of traffic demand. We consider a heterogeneous cellular system where the elements of it can adapt and change their architecture depending on the network demand. We demonstrate substantial savings of energy, especially in low-traffic periods where most mobile systems are over engineered. Energy savings are also achieved in high-traffic periods by capitalising on traffic variations in the spatial domain. We adopt a fuzzy-logic algorithm for the multi-objective decisions we face in the system, where it provides stability and the ability to handle imprecise data
SCALABLE AND EFFICIENT VERTICAL HANDOVER DECISION ALGORITHMS IN VEHICULAR NETWORK CONTEXTS
A finales de los años noventa, y al comienzo del nuevo milenio, las redes inalĂĄmbricas han evolucionado bastante, pasando de ser sĂłlo una tecnologĂa prometedora para convertirse en un requisito para las actividades cotidianas en las sociedades desarrolladas. La infraestructura de transporte tambiĂ©n ha evolucionado, ofreciendo comunicaciĂłn a bordo para mejorar la seguridad vial y el acceso a contenidos de informaciĂłn y entretenimiento.
Los requisitos de los usuarios finales se han hecho dependientes de la tecnologĂa, lo que significa que sus necesidades de conectividad han aumentado debido a los diversos requisitos de las aplicaciones que se ejecutan en sus dispositivos mĂłviles, tales como tabletas, telĂ©fonos inteligentes, ordenadores portĂĄtiles o incluso ordenadores de abordo (On-Board Units (OBUs)) dentro de los vehĂculos. Para cumplir con dichos requisitos de conectividad, y teniendo en cuenta las diferentes redes inalĂĄmbricas disponibles, es necesario adoptar tĂ©cnicas de Vertical Handover (VHO) para cambiar de red de forma transparente y sin necesidad de intervenciĂłn del usuario.
El objetivo de esta tesis es desarrollar algoritmos de decisión (Vertical Handover Decision Algorithms (VHDAs)) eficientes y escalables, optimizados para el contexto de las redes vehiculares. En ese sentido se ha propuesto, desarrollado y probado diferentes algoritmos de decisión basados en la infraestructura disponible en las actuales, y probablemente en las futuras, redes inalåmbricas y redes vehiculares. Para ello se han combinado diferentes técnicas, métodos computacionales y modelos matemåticos, con el fin de garantizar una conectividad apropiada, y realizando el handover hacia las redes mås adecuadas de manera a cumplir tanto con los requisitos de los usuarios como los requisitos de las aplicaciones.
Con el fin de evaluar el contexto, se han utilizado diferentes herramientas para obtener informaciĂłn variada, como la disponibilidad de la red, el estado de la red, la geolocalizaciĂłnMĂĄrquez Barja, JM. (2012). SCALABLE AND EFFICIENT VERTICAL HANDOVER DECISION ALGORITHMS IN VEHICULAR NETWORK CONTEXTS [Tesis doctoral no publicada]. Universitat PolitĂšcnica de ValĂšncia. https://doi.org/10.4995/Thesis/10251/17869Palanci
A Genetic Algorithm-based Framework for Soft Handoff Optimization in Wireless Networks
In this paper, a genetic algorithm (GA)-based approach is used to evaluate the probability of successful handoff in heterogeneous wireless networks (HWNs) so as to increase capacity and network performance. The traditional handoff schemes are prone to ping pong and corner effects and developing an optimized handoff scheme for seamless, faster, and less power consuming handoff decision is challenging. The GA scheme can effectively optimize soft handoff decision by selecting the best fit network for the mobile terminal (MT) considering quality of service (QoS) requirements, network parameters and userâs preference in terms of cost of different attachment points for the MT. The robustness and ability to determine global optima for any function using crossover and mutation operations makes GA a promising solution. The developed optimization framework was simulated in Matrix Laboratory (MATLAB) software using MATLABâs optima tool and results show that an optimal MT attachment point is the one with the highest handoff success probability value which determines direction for successful handoff in HWN environment. The system maintained a 90% Â with 4 channels and more while a 75% was obtained even at high traffic intensity
Mobility and Handoff Management in Wireless Networks
With the increasing demands for new data and real-time services, wireless
networks should support calls with different traffic characteristics and
different Quality of Service (QoS)guarantees. In addition, various wireless
technologies and networks exist currently that can satisfy different needs and
requirements of mobile users. Since these different wireless networks act as
complementary to each other in terms of their capabilities and suitability for
different applications, integration of these networks will enable the mobile
users to be always connected to the best available access network depending on
their requirements. This integration of heterogeneous networks will, however,
lead to heterogeneities in access technologies and network protocols. To meet
the requirements of mobile users under this heterogeneous environment, a common
infrastructure to interconnect multiple access networks will be needed. In this
chapter, the design issues of a number of mobility management schemes have been
presented. Each of these schemes utilizes IP-based technologies to enable
efficient roaming in heterogeneous network. Efficient handoff mechanisms are
essential for ensuring seamless connectivity and uninterrupted service
delivery. A number of handoff schemes in a heterogeneous networking environment
are also presented in this chapter.Comment: 28 pages, 11 figure
Survey Paper: Mobility Management in Heterogeneous Wireless Networks
AbstractEver increasing user demands and development of modern communication technologies have led to the evolution of communication networks from 1st Generation (1G) network to 4G heterogeneous networks. Further, 4G with heterogeneous network environment will provide features such as, âAlways Best Connectedâ, âAnytime Anywhereâ and seamless communication. Due to diverse characteristics of heterogeneous networks such as bandwidth, latency, cost, coverage and Quality of Service (QoS) etc., there are several open and unsolved issues namely mobility management, network administration, security etc. Hence, Designing proficient mobility management to seamlessly integrate heterogeneous wireless networks with all-IP is the most challenging issue in 4G networks. Mobile IPv6 (MIPv6) developed by Internet Engineering Task Force (IETF) has mobility management for the packet-switched devices of homogeneous wireless networks. Further, mobility management of homogeneous networks depends on network related parameter i.e., Received Signal Strength (RSS). However the mobility management of heterogeneous networks, not only depends on network related parameters, but also on terminal-velocity, battery power, location information, user-user profile & preferences and service-service capabilities & QoS etc. Designing mobility management with all-IP, while, considering issues such as context of networks, terminal, user and services is the main concern of industry and researchers in the current era
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