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Ítem Technological Models of Municipal Wireless Networks based on Hybrid WiFi/WiMAX Mesh Networks: a proposal to Colombian Municipalities(Ieee, 2009-10-30) Rodríguez Hernández, Pedro SalvadorThe telecommunications infrastructure citizen-oriented has become a necessity in cities that wish to direct themselves to a new Information Society. One of the technological alternatives for these infrastructures is municipal wireless networks. These municipal wireless networks offer flexibility, speed of installation and less implementation costs for cities. For this reason, it is considered of interest the wider use of wireless networks for the Colombian municipalities, considers that in this environment there is limited budget and low rate of connectivity to broadband networks. This article presents a review of the current state of municipal wireless networks related to the technological aspects, with the intention to propose two technological architectures that may be feasible to implement in the Colombian municipalitiesÍtem Seguridad en redes inalámbricas 802.11(Universidad Icesi, 2006-07-28) Madrid Molina, Juan ManuelLack of security in wireless LANs is a problem which has not been correctly assessed by network managers and people in charge of information, in spite of its seriousness. This article presents the existing technologies for heightening the security level in 802.11 wireless LANs, among with their advantages, disadvantages and application scenarios.Ítem Herramienta gráfica de modelado de redes inalámbricas basada en modelos de propagación de señales en interiores(Universidad Icesi, 2006-07-28) Osorio Betancur, Juan David; López Ocampo, Sandra Paulina; Navarro Cadavid, AndrésEl presente artículo describe el proceso de implementación de un modelo de predicción de la propagación de señales en interiores, basado en el modelo semiempírico de K. W. Cheung, J. H. M. Sau, y R. D. Murch,[1] donde se tienen en cuenta la atenuacióndebida a la distancia, el ángulo de incidencia sobre las paredes, laatenuación asociada a estas mismas y las zonas de Fresnel.Los datos del entorno a simular son tomados de un archivo DXF que debe seguir un formato establecido. Se obtienen del usuario la atenuación asociada a cada tipo de pared y la ubicacióndel punto de acceso. También se desarrolla un algoritmo desombreado que optimiza el tiempo de simulación debido a su sencillez. Finalmente se muestra la comparación de los resultados de la simulación y los datos obtenidos en la prueba de campo.Ítem Performance evaluation of Vertical Handoff Algorithms(IEEE, 2010-10-10) Navarro Cadavid, AndresDifferent Vertical Handoff Algorithms (VHA) have been proposed in the literature recently. However, there is no consensus on how to evaluate performance of different VHA at the research community. Although some models have been proposed for evaluation of the VHA, this issue is a challenge because the VHA have evolved to become more sophisticated, thus the evaluation models must consider a variety of parameters. In this paper, we propose a new evaluation model for VHA that has been designed based on specific concepts taken from the multi-criteria evaluation and operational reliability. The proposed evaluation model allows analyzing VHA using measured values of some defined parameters, which can be obtained from simulating VHA on a network simulation tool. We present as a case study an evaluation of two VHA that shows the new model functionality and results. © 2010 IEEE.Ítem QoS and multipath routing in vehicular network(ACM Press, 2007-05-14) Umaña, Sandra CéspedesLas redes Vehiculares Ad-Hoc o redes VANET, consisten en la asociación espontánea de un conjunto de vehículos equipados con tecnología de comunicación inalámbrica, que circulan y cambian dinámicamente su posición e intercambian datos entre sí. Estas redes fueron pensadas como segmentos autónomos y de direccionamiento plano, sin embargo, su estudio ha mostrado los beneficios de interconectarlas a segmentos de redes de infraestructura e Internet. El presente artículo revisa, mediante el uso de una herramienta de simulación, las mejoras globales de las métricas de calidad de servicio de la red, logradas mediante el uso de un protocolo de ruteo multi caminos. El modelo consta de un segmento de red fija (Internet), dos gateway reactivos y dos segmentos jerárquicos de redes VANET IPv6, las cuales están compuestas por nodos con alto grado de movilidad, tales como los vehículos en un entorno urbano.Ítem Caracterización del consumo de energía y el desempeño de las aplicaciones streaming sobre redes inalámbricas WLA N(Universidad Icesi, 2008-07-24) Garnica, Juan Pablo; Marín, Andrés; Aedo Cobo, José EdinsonToday’s society requires people to be connected anyplace, anytime, thorough different media, such as test, audio and video. This requirement explains the high adoption rate of streaming applications and wireless LANSs (WLANs), and the increasing research in these topics. This article presents the power consumption characterization for a laptop computer running a streaming multimedia application over a WLAN, as well as the profile for the WLAN performance while the multimedia application is running. We found that the laptop power consumption changes depending of the network adapter in use, and the network performance is related to the type of media being transmitted over the network, to the communication channel conditions, and the protocol stack implementation.Ítem Traspasos verticales: visión general e innovaciones(Universidad Icesi, 2010-03-24T23:21:22Z) Ríos López, Carlos AndrésIn zones where wireless access networks of various type, coverage, technology and capacity are available, mobility has to deal with the user equipment’s ability to seamlessly switch between different links, even in the middle of an active session. The network has to continuously cope with the selection of a possible new channel for the mobile terminal, and the soundness of this decision has a tremendous impact on the overall performance of the network and quality of service. This survey presents vertical handover related background, research challenges an state-of-the-art proposals in this field.Ítem Arquitecturas tecnológicas y modelos de negocio para un operador de Hotspots inalámbricos WI-FI.(Universidad Icesi, 2006-10-11) Varela, Claudia P.; Escandón, Alfredo; Castillo, Hector F.; Murillo, Sandra L; Millán, Andrés Felipe; Zúñiga Cañón, Claudia LilianaThis paper presents technology architectures and business models in wireless hotspot Wi-Fi service providers market. Besides to describe a business and technology model for Broadband Wireless Network (RIBA) of EMCALI Local Service Provider, this could be implemented in the Wireless Hotspots Colombian Providers.Ítem Up-Link/Down-Link capacity Unbalance analysis in UMTS using a GIS based Planning Tool and MATLAB simulation(WNCG 2003 Wireless Networking Symposium, 2003, Austin, 2003-01-01T16:44:31Z) Navarro Cadavid, AndrésCapacity analysis using simulation is not a new thing in literature. Most of the development process of UMTS standardization have used simulation tools; however, we thing that the use of GIS planning tools and matrix manipulation capacity of MATLAB can show us different scenarios and make a more realistic analysis. Some work is been doing in COST 273 in order to have more realistic scenarios for UMTS planning. Our work initially was centered in uplink analysis, but we are now working in downlink analysis, specifically in two areas: capacity in number of users for RT and NRT services, and Node B power. In this work we will show results for up-link capacity and some results for downlink capacity and BS power consumption.Ítem Vertical handoff algorithms - A new approach for performance evaluation(IEEE, 2010-12-06) 2010 IEEE Globecom Workshops, GC'10A myriad of Vertical Handoff Algorithms (VHA) have been proposed by researchers and networks practitioners. These algorithms allow mobile terminals (MT) to maintain the network connection when they switch from one wireless network to another one. Given the amount of proposed VHA and the need for an objective assessment of these solutions different evaluation methodologies have been proposed, becoming the problem of evaluation of VHA in an interesting challenge. However, there is no consensus on how to evaluate performance of VHA. In this paper, we address this issue by proposing a new approach for evaluating the VHA, which is based on multi -criteria evaluation and criticality analysis - a specific concept taken from the operational reliability. The new approach allows evaluating VHA using measured values of some defined parameters, which can be obtained from simulating VHA on a network simulation tool (e.g. NCTUns, NS -2, OMNET++, among others) or generic software simulation tools (e.g. MATLAB). As a test of the new model, an evaluation of five VHA is presented
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