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Electronics, Communications and Computers, 2006. CONIELECOMP 2006. 16th International Conference on

Date March 1 2006-Feb. 27 2006

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Displaying Results 1 - 25 of 65
  • 16th International Conference on Electronics, Communications and Computers - Cover Page

    Page(s): c1
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  • 16th International Conference on Electronics, Communications and Computers - Title Page

    Page(s): i - iii
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  • 16th International Conference on Electronics, Communications and Computers - Copyright

    Page(s): iv
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  • 16th International Conference on Electronics, Communications and Computers - Table of contents

    Page(s): v - xiii
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  • Chairs welcome

    Page(s): xiv
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  • Acknowledgements

    Page(s): xv
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  • Organizing Committee

    Page(s): xvi
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  • Participating Institutions

    Page(s): xviii
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  • Approaching a Capacity Expansion Problem in Telecommunications

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (83 KB) |  | HTML iconHTML  

    The problem of expanding the capacity of a single facility in telecommunications network planning is addressed. Two models, corresponding to two different policies to approach the problem, are developed and tested. The first policy looks for the best solution in each isolated period the second one is a multi-period point of view. Computational results show that the second policy is considerably better. View full abstract»

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  • VoWF (Vo-IP over Wi-Fi)

    Page(s): 2
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    Wireless telephony has become very popular in the past few years. However, the high costs of cellular systems make it necessary to find different technologies that can reduce the prices while keeping the efficiency and mobility. For this reason we explored the advantages and disadvantages of VoIP over Wi-Fi (VoWF), which means using wireless networks based on the IP protocol (like internet) to transmit voice. In this project we tested the performance of VoWF using Skype and X-Lite which are VoIP softwares and demonstrated to have similar behavior. We also used a software called WirelessMon that allowed us to monitor the status of the wireless network. Although VoWF has many advantages like low cost and easy implementation, we concluded that this technology is not ready to substitute cellular systems like GSM because it has three major problems which are: long handoff time, low range and low capacity. However VoWF can be a good complement for GSM. View full abstract»

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  • Wireless Sensor Network and Remote Data Acquisition System for Mobile Applications

    Page(s): 3
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    In this work, a network based on wireless sensing modules has been developed to measure strains, temperature and accelerations in multiple points of the vehicle. The obtained data of each sensor is prepared, processed, stored and transmitted in time intervals towards a receiver. The receiver in turn sends the information to an Internet server through GSM cellular technology using the GPRS protocol. In the server, the data is stored and analized as it is received so it can be visualized as close as real time as possible by anyone with access to the Internet. View full abstract»

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  • Satellite-Indoor Mobile Communications Path Propagation Losses

    Page(s): 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB) |  | HTML iconHTML  

    A software that calculates satellite indoor loss path for three different systems of mobile satellite communications is presented. The systems are GLOBALSTAR , IRIDIUM and a third option for a GENERAL system in which the user have the possibility of change some parameters of the calculations. The user can choose from 5 different indoor propagation models. The software was developed using Visual Basic. View full abstract»

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  • Mobile Network Evolution toward 3G: A Techno-Economic Analysis

    Page(s): 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB) |  | HTML iconHTML  

    This paper addresses technical and economical aspects to configure a Third Generation (3G) mobile cellular network. Major components of costs and revenues and the major stakeholders are identified and a methodology is developed to compare the main factors affecting the business case of 3G operators and builds a model that estimates the profitability of different scenarios. An open issue, both from the technical and economic points of view, is to identify the requirements and the necessary steps to migrate from 2G to 3G mobile cellular networks. A number of mobile network evolution strategies toward 3G were generated and evaluated using the TERA model. Initial economic conclusions have been derived, presented and discussed using key profitability factors such as Net Present Value (NPV), and Payback Period. View full abstract»

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  • An Evaluation on the Signal-to-Interference Ratio Performance of a Circular Array in CDMA Systems

    Page(s): 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB) |  | HTML iconHTML  

    This paper deals with the interference rejection capability of circular antenna arrays used for smart antenna systems, at base station of a CDMA communications system. In general, this figure of merit depends strongly on the array configuration and is a function of the direction of arrival of the desired signal, the number of antenna elements, and their spacing. The main goal and contribution of this letter is to extend a previous result on the interference rejection capability for uniform linear arrays, to the uniform circular arrays case. A detailed presentation of the behavior of the interference rejection capability of uniform circular arrays is provided, the effect of varying the number of its elements and inter-element spacing on the SIR (signal-to-interference ratio) performance is considered. Analytical results, for the total average of spatial interference suppression coefficient for circular arrays, as a function of inter-element spacing, are provided. These results are compared with a previous result for the linear array case. View full abstract»

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  • Compute rain attenuation. An approach supported in ITU-R recommendations for the Ku Band

    Page(s): 9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (112 KB) |  | HTML iconHTML  

    The methodologies for the Attenuation prediction models due to rain attenuation in frequencies above 10 GHz can be separated by utilization of the input data. The methods based in measurement and experimental data. The last one method is founded on databases from automatic meteorological stations located in different climatic zones within given geographical zone. ' One of the most used method using empiric data it is based in ITU logical process. This methodology has the technical name of ITU-R P.618 Recommendation: "Propagation data and prediction methods required for the design of Earth-space telecommunication systems". As is mentioned this Recommendation, it is extremely important that the methods for the propagation prediction parameters demonstrate in Recommendation P.618 be imported for planning Earth-space links in frequencies above to 10 GHz [1]. Following the regards above, the process to computation of long-term rain attenuation statistics from point rainfall rate is next developed. View full abstract»

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  • Control System Over Power Line

    Page(s): 10
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB) |  | HTML iconHTML  

    It is a basic prototype of a smart control system for electric energy. The circuit controls the provision of energy in each receiving point of the system like electrical lamps, devices and other devices using the mains like mass media. In this prototype the power station receives the data entered by keyboard, soon these data codifies them, generates a frequency, modulates them and transmits on the alternating signal through the existing electrical wiring towards the receiver located in the same mains which demodulates, detects the frequency and decode the data that via optical connection control the firing of tríac activating or deactivating the electrical provision towards the load connected in the receiver. For his complete version one projects to have a programmable power station, that accepts originating data of a PC (local program or page Web), via telephone line (conventional telephony or IP), in these cases the data enter through an interphase. The distance present average of this prototype is of 70 mts, optimizing its yield a maximum distance is considered of 100mts of wiring of the horizontal and vertical mains and it cost is approximately $ 20. (Tx + 1Rx) View full abstract»

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  • Improving Least-Squares-Based VBLAST Architecture with Conventional Channel Coding

    Page(s): 11
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB) |  | HTML iconHTML  

    New demands in wireless communications imply an important increase in channel capacity and thoughput. In recent years, research in wireless communications has focused mainly in the utilization of spatial and temporal diversity in both transmission and reception by means of antenna arrays at both ends, in order to achieve this increase in channel capacity. These MIMO (Multiple-Input Multiple-Output) systems, to work properly and guarantee its potential advantages, demand powerful signal processing procedures so as to recover the signal transmitted by the antenna arrays in the best possible way. Among the different signal processing algorithms that exist for these MIMO systems, the BLAST algorithm has come to be a potential alternative for its excellent complexity-performance tradeoff. This system has different realizations. In this paper, we concentrate on a Least-Squares based VBLAST architecture and propose a simple means for improving further its performance. Indeed, with the concatenation of a conventional convolutional coder, the overall performance can be increased in 3 dB while increasing the complexity in an acceptable way. Results are also compared to the quasioptimal Closest Point (CP) decoder. It is shown that our proposed system outperforms the CP algorithm by 3 dB for the same antenna arrays, and for the same computational complexity, our proposed system is better by 4 dB. View full abstract»

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  • Decoding Vertical Space-Time Codes with Least-Squares Techniques

    Page(s): 12
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    In this paper, we propose and compare three algorithms based on Bell Labs’ vertical space-time codes (V-BLAST) and examine their block error rate and their algorithmic complexity for different combinations of block length and number of antennas. Of special interest are two algorithms that use least-squares techniques, specifically the QR decomposition, to substantially lower the complexity of the original V-BLAST. We present the algorithms in detail as well as simulation results and experimental results based on a high-performance digital signal processor. We show that the algorithm of choice depends on the number of antennas in the system, the block length L, and on whether the application at hand requires low-error rates or low-complexity. View full abstract»

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  • Simulation Platform for MIMO Systems

    Page(s): 13
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB) |  | HTML iconHTML  

    A computer simulator package for MIMO systems is presented. This simulator is highly configurable, easily extensible, and can generate exhaustive performance and complexity measurements. Examples of use and capabilities are shown. The simulator’s source code has been released to the research community under an open-source license. View full abstract»

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  • Selective Modulation performance under Markovian Fading Channel Model

    Page(s): 14
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB) |  | HTML iconHTML  

    Channel modeling is a powerful tool to simulate a mobile communication system performance as shown in [5] and [1] with two or more states using Markov chains. It has been shown that this method simulates with good approximations the real conditions that a communication mobile systems suffer at determined link such as [6], where several places experiment signal fading and multipath phenomenon. With an appropriate simulation method using n States Markov Chains, it is possible to improve receivers performance investigating altering protection methods, as shown in [9]. This work will compare some scenarios, to probe that statistical distributions can be utilized to approach such fading conditions. View full abstract»

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  • Micromachined Transmission Lines for Millimeter-Wave Applications

    Page(s): 15
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    Several different fabrication techniques and materials have been proposed for making low loss high performance micromachined transmission lines. In this paper a review of several micromachined transmission lines that have been proposed over the last years are classified into four types according to their physical structure and their power losses addressed. View full abstract»

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  • Low Cost Visual Event Detection over JPEG Flows

    Page(s): 16
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB) |  | HTML iconHTML  

    For video surveillance systems, visual event detection is an interesting resource since it can reduce the volume of data to be transmitted or stored. Furthermore, visual event detection offers information about physical events occurring inside the scene. This article presents a low cost algorithm for visual event detection. The proposed algorithm is based on the partial decoding of the JPEG (Joint Picture Expert Group) flow produced by the IP cameras hardware and the analysis of the DCT (Discrete Cosine Transform) coefficients on contiguous frames. Two are the main advantages of this algorithm: It runs over a reduced memory space and it is inexpensive in terms of CPU resources. In order to show the advantage of the proposed algorithm, a visual event detection system has been implemented in C language over Linux. View full abstract»

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  • One Method for Design of Wide-band FIR Filters Without Multipliers

    Page(s): 17
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB) |  | HTML iconHTML  

    This paper presents the method for the wide-band FIR filters design without multipliers. The proposed method is based on the masking method and the techniques for rounding and sharpening. The coefficient values of the model and masking filters are represented as integers using the rounding technique. The sharpening technique is applied to the masking filters to improve the overall magnitude characteristic and to satisfy the given specification. View full abstract»

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