8 resultados
Resultados de la búsqueda
Mostrando 1 - 8 de 8
Ítem W-CDMA capacity analysis using GIS based planning tools and MATLAB simulation(IEEE, 2000-03-29) 1st International Conference on '3G Mobile Communication TechnologiesThe evolution of cellular systems towards third generation (3G) or IMT-2000 seems to have a tendency to use W-CDMA as the standard access method, as ETSI decisions have showed. However, there is a question about the improvements in capacity and the wellness of this access method. One of the aspects that worry developers and researchers planning the third generation is the extended use of the Internet and more and more bandwidth hungry applications. This work shows the performance of a W-CDMA system simulated in a PC using cover maps generated with DC-Cell, a GIS based planning tool developed by the Technical University of Valencia, Spain. The maps are exported to MATLAB and used in the model. The system used consists of several microcells in a downtown area. We analyse the interference from users in the same cell and in adjacent cells and the effect in the system, assuming perfect control for each cell. The traffic generated by the simulator is voice and data. This model allows us to work with coverage that is more accurate and is a good approach to analyse the multiple access interference (MAI) problem in microcellular systems with irregular coverage. Finally, we compare the results obtained, with the performance of a similar system using TDMA.Ítem Some parameters that affect CDMA capacity analysis. Results using GIS based simulation(3G Mobile Communication Technologies, 2001. Second International Conference, 2001-01-01T15:55:51Z) Cardona Marcet, Narcís; 2nd International Conference on 3G Mobile Communication TechnologyIn previous papers we describe a model for capacity analysis in CDMA systems using DC-Cell, a GIS based planning tool developed at Universidad Politecnica de Valencia, and MATLAB. We show some initial results of that model, and now, we are exploring different parameters like cell size, proximity between cells, number of cells in the system and “clustering” CDMA in order to improve the planning process for third generation systems. In this paper we show the results for variations of some of these parameters, specifically the cell size and number of cells. In CDMA systems is quite common to suppose only one carrier frequency for capacity estimation, and it is intuitive to think that for more base stations, mean more users. However the multiple access interference problem in CDMA systems could establish a limit for that supposition in a similar way that occurs in FDMA and TDMA systems.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 Análisis de capacidad en sistemas CDMA y WCDMA, usando herramientas de planificación basadas en GIS y dinámica poliédrica(Universitat Politècnica de València, 2003-10-17) Navarro Cadavid, Andrés; Cardona Marcet, NarcísEn este momento están entrando en operación los primeros sistemas UMTS en Europa, y están operando en varios países del mundo sistemas CDMA-2000 1xRTT, y aunque existen muchos trabajos publicados sobre la capacidad de estos sistemas, prácticamente todo lo existente se basa en el comportamiento de sistemas ideales que consideran celdas hexagonales o circulares y propagación basada en exponente inverso de la distancia y poco es lo que hay sobre el comportamiento real de dichos sistemas en entornos reales.
Sobre el exponente de pérdidas de propagación, es bien conocido que este afecta la capacidad de los sistemas CDMA; sin embargo hasta ahora no se ha considerado el efecto de los modelos de propagación que tienen en cuenta la difracción y otros fenómenos más cercanos a la realidad, y por lo tanto no se ha considerado el efecto del entorno urbano y el terreno sobre la capacidad real de los sistemas basados en CDMA.
Ítem Simulation and analysis of compressed sensing technique as sampling and data compression and reconstruction of signals using convex programming(Institute of Electrical and Electronics Engineers Inc., 2016-12-14) Navarro Cadavid, Andrés; 21st Symposium on Signal Processing, Images and Artificial Vision, STSIVA 2016The information management has been treated primarily under the Nyquist sampling theory, but it is important to introduce new theories that replace deficiencies of what we know as the classical theory of sampling. These deficiencies create difficulties in data acquisition; this is a problem when large volumes of information are handled, in addition to the higher costs in storage and processing. This article presents the results obtained from the compressed sensing simulation technique applied to two types of signals. The aim of this paper was to simulate a communication system involving the data recovery applying the compressed sensing technique, analyzing sampling rates reduction, measuring the efficiency of the process and the behavior of the technique. The recovery of the signal is made using convex programming and using l1 norm minimization for recover the signals in the time domain. We used the L1Magic toolbox, which is a set of Matlab® functions used to solve optimization problems in this case with the l1eqpd function. As a summary of the obtained results, we checked the efficiency of the compressed sensing technique, minimum average rates for sampling the constructed signals, and the best performance of the technique to recover soft signals compared to non-differentiable signals. Additionally, the recovery results of an audio signal with the compressed sensing technique, by varying the sampling rate and checking the audibility of the signal, are presented. This allowed the testing of this technique in a real scenario, finding a good opportunity for the transmission of audio signals in a more efficient way.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 presentedÍtem Analysis of the influence of sectorization in the capacity of WCDMA using topological invariants(Lu W.W., 2005-05-17) Navarro Cadavid, AndrésPolyhedral analysis and simplicial complexes have been used in areas such as database design, traffic and social sciences, since work from Atkin. In this paper we make a short introduction on simplicial complexes and then propose the use of some topological invariants of simplicial complexes such is the structure vector to qualitatively predict the capacity of a WCDMA system and improve the planning process of CDMA based systems used in third generation. We compare results obtained from structural vector with results obtained from a dynamic simulator in order to show the relation between structural vector and capacity.Ítem Body Area Networks: Channel Models and Applications in Wireless Sensor Networks(IGI Global, 2011-01-01) Betancur Agudelo, LeonardoNowadays, wireless Body Area Networks (wBAN) have gained more relevance, in particular in the areas of health care, emergencies, ranging, location, domotics and entertainment applications. Regulations and several wireless protocols and standards have appeared in recent years. Some of them, like Bluetooth, ZigBee, Ultra Wide Band (UWB), ECMA368, WiFi, GPRS and mobile applications offer different kinds of solutions for personal area communications. In this chapter, body area network channel modelling will be described; also, a brief description of the applications and state-of-the-art of regulation and standardization processes pertaining to these kinds of networks will be presented. For each topic, the chapter shows not only the main technical characteristics, but also the technical problems and challenges in recent and future research. Finally, the chapter provides an analysis of Body Area Networks, opinions about the future and possible scenarios in the short- and medium-term for the development of standards and applications and their impacts on our daily lives.