Volume 1, Issue 2, July 2011


Remote Sensing Satellite Data Simulator [Download Paper]

A. A.N.Satyanarayana, B. Y.Venkatarami Reddy and C. B.C.S. Rao


Abstract— Remote Sensing Satellites orbit around the Earth around 600-900 kms. in sun synchronous polar orbit.Each satellite trans-mit the image data in X-band and the data reception is carried out through a parabolic antenna along with the associated systems. The entire data acquisition system is complex and expensive as it has to meet the requirements of the fast orbiting remote sensing satel-lites. During the visibility of the satellite, the data is acquired at the acquisition systems, frame synchronized band separated and dis-played in the monitor in real-time. This Remote sensing Satellite Data Simulator (RSDS) is required for qualitative and quantitative analysis of data reception chain as well as Level-0 product generation chain. Qualitative analysis involves frame sync lock/loss moni-toring on front-end hardware, pattern correctness on display, presence of pixel dropouts and line losses. Quantitative analysis involves analyzing the raw simulation data file through software, i.e., frame sync losses, correctness of mode, channel id, line count update; video data check with expected pattern values etc. PN-sequence mode of SDS can be used for receive chain can be BER (Bit Error Rate) evaluation. This paper describes the performance of errors and characterizing the same for error-free data reception and online diagnostics.


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Performance Analysis of Channel Spacing in Wavelength Division Multiplexed Optical Fiber Communication System
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Hardeep Singh


Abstract — In this paper, the simulation results have been presented for dispersive optical communication with different channel spacing. The channel spacing has been put in a run and its impact on four wave mixing is observed. The results have been presented and it is observed that of all the channel spacing’s, the 1.5 nm channel spacing is best suited for dispersive optical communication systems. Initially, four wave maxing was high with less channel spacing and later on it get decreased due to more channel spacing It is observed that the optical power in the channel increases with the increase of channel spacing. Further, it is investigated that eye opening is more for high channel spacing. Besides this, both the correlation diagrams for eye opening and eye closing have been observed for different channel spacings. Moreover, the Q factor has been observed for efficient optical fiber communication systems.

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Dependent Communication Systems: A New Approach for Designing Communication Infrastructures of Smartgrid
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Mohammad Shahraeini, Mohammad H. Javidi, and Mohammad S. Ghazizadeh


Abstract—The term “smartgrid” refers to the power system that integrates new digital measurements, new digital control devices, and communication technology. The first step toward this goal is to establish a two-way communication infrastructure for the purpose of data delivery among data resources, system actuators and control centers. Phasor measurement unit (PMU) is a kind of new data resources that are widely used in power systems, recently. On the other hand, state estimation (SE) is basis application in control centers and it is known as kernel of other smartgrid applications. This study aims to plan a communication infrastructure that creates communication routes from PMUs of a SE to the control center in a power network. To do this, a new concept is introduced to power system communication called dependent communication system (DCS). A DCS has been made by independent transmission media (e.g. optical power grand wire), which is typically attached to the
power systems. In this paper, OPGW based DCS designing problem is formulated as an optimization problem. This optimization problem is solved by genetic algorithm. It will be shown that DCS planning is an effective and flexible approach for designing communication infrastructures of smart grids. The results confirm that almost 25 percent of lengths of transmission lines should be covered by OPGW in order to create communication routes from PMUs to the control center. Hence, it is proved that the price of high speed, reliable and secure communication infrastructure of a smartgrid is considerable in comparison with the price of data resources e.g. PMUs.

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Spectrum Sensing Using Cyclic Prefix Over Fading Channels and Performance Analysis of Cooperative Detection
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Komal Arora, Ankush Kansal and Kulbir Singh


Abstract—Spectrum shortage has become one of the critical problems in the wireless communications. Cognitive Radio technology has been introduced as an attractive solution to tackle with this problem by utilizing the spectrum which remains unused most of the time. In order to detect the unused portion of the spectrum, spectrum sensing techniques are used. In this paper, cyclic prefix, a special feature embedded in the OFDM signals is used for spectrum sensing. Closed form expressions for Probability of detection for AWGN and Rayleigh channels are described. Cooperation among the users is a valuable tool in the implementation of the spectrum sensing and it improves the performance of cyclic prefix based spectrum sensing up to 3.9 times as compared to the single user.

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Performance analysis of Linear Multi-user Detection Techniques in the presence of Interference
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Er. Komal Babbar


Abstract— Multiuser Detection (MUD) techniques are used to improve capacity and also area of research. The demand for cel-lular wireless services, recent interests are in techniques, which can improve the capacity of CDMA system. One such a tech-nique is multiuser detection techniques can substantially increase the capacity of CDMA systems. These technique are used to remove MAI occurs when more then one user is detected. The author has presented the conventional method of demodulating mutually interfering signals: the Matched filter, Decorrelating receiver and MMSE. The author investigates the performance analysis for three receivers under the presence of interference and noise. This problem arises in CDMA applications because the DS-CDMA allows large no. of users to share the same spectrum resources but suffer from MAI and channel distortion. In particular the MAI is one of the main factors that limits both capacity and performance of CDMA. The MATLAB simulation used for analysis and in the last section author also shows Matlab Simulation results for Multi-user detection techniques i.e., Matched filter, Decorrelating, MMSE for 2 users and 10 users.

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RTU Hardware Design of SCADA Systems Using FPGA
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Hamid Reza Naji and Soroush Shirali


Abstract—The Remote Terminal Units (RTUs) are crucial elements in SCADA systems which are responsible for data acquisition in substations, and accomplishment of central station commands. In this work we present a new hardware design for an RTU that performs basic functions of the RTU. This design is made by FPGA and offers high speed of operation and ample variety of configurations and high reliability.

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Effect of Length on WDM Dispersion-Managed Transmission System Using Dispersion Compensating Fiber
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Hardeep Singh


Abstract—In conventional long-distance wavelength-division multiplexed (WDM) Dispersion - managed transmission systems, since both the dispersion-shifted fiber (DSF) and the standard single-mode fiber (SMF) have positive dispersion slope. The transmission window of such systems is severely limited by the interplay between the self-phase modulation and the residual dispersion. In contrast, WDM dispersion managed systems comprised of a SMF followed by a higher order dispersion compensation fiber (DCF) with opposite second and third-order dispersions can clear out this drawback. This paper simulates the 16- channels WDM optical communication system to investigate the effect of length of SSMF and the effect is seen from the eye diagram, optical spectrum and BER diagram.

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Dual-Link Failure Resiliency through BLME
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Mr. Sushant Mangasuli, Dr. D V Ashoka and Mr. Prashant Ankalagi


Abstract— Networks employ link protection to achieve fast recovery from link failures. While the first link failure can be protected using link protection, there are several alternatives for protecting against the second failure. This paper formally classifies the approaches to dual-link failure resiliency. One of the strategies to recover from dual-link failures is to employ link protection for the two failed links independently, which requires that two links may not use each other in their backup paths if they may fail simultaneously. Such a requirement is referred to as backup link mutual exclusion (BLME) constraint and the problem of identifying a backup path for every link that satisfies the above requirement is referred to as the BLME problem. This paper develops the necessary theory to establish the sufficient conditions for existence of a solution to the BLME problem. Solution methodologies for the BLME problem is developed using two approaches by: 1) formulating the backup path selection as an integer linear program; 2) developing a polynomial time heuristic based on minimum cost path routing. The ILP formulation and heuristic are applied to six networks and their performance is compared with approaches that assume specific knowledge of dual-link failure. It is observed that a solution exists for all of the six networks considered. The heuristic approach is shown to obtain feasible solutions that are resilient to most dual-link failures, even though the backup path lengths may be significantly higher than optimal.


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Survey of Reliability Theories of the Last 50 Years [Download Paper]

Asis Sarkar, Dhiren Kumar Behera and Dr Bijan Sarkar


Abstract— This paper is dedicated to all the researchers for their contributions in reliability theories and developments, in the past 50 years. The paper provides a summary on the pioneers of reliability theories, and how their works placed a great influence on our reliability analysis today. This is also a survey paper on Reliability theorirs and methods. The information provided in this paper is mostly based on to provide as much a neutral view as possible. Area of interest in the reliability analysis included representation of reliability parameters, renewal theory, coherent structure, diagram-based models, theoretical methods, and other miscellaneous techniques. Diagram based models included block diagrams, Fault Tree Analysis (FTA), Event Tree Analysis, and flow graphs. The contributions of reliability researchers like, Weibull, Epstein and Sobel had made a significant influence on the distribution functions and Lotka, Campbell, Smith, Barlow, and Proschan, had advanced the theories for reliability. In fact this will be the guidelines for the coming generation for further research in the field of their own interest.