M Tech Dissertations

Permanent URI for this collectionhttp://drsr.daiict.ac.in/handle/123456789/3

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Subject: search.filters.subject.Radio & TV communications equipment

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Now showing 1 - 3 of 3
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    Spectrum sensing in cognitive radio using quickest change detection framework
    (Dhirubhai Ambani Institute of Information and Communication Technology, 2015) Bharmal, Sara; Pillutla, Laxminarayana S.
    Spectrum sensing is a term associated with detection of primary (licensed) users (PU) by secondary (unlicensed) users (SU) to pursue opportunistic transmission of their data. The problem of spectrum sensing is challenging because of the distributed nature of SU. Since the presence or absence of PU has to be detected as quickly as possible therefore we use an approach based on quickest detection. To improve sensing efficiency we assume the SU to be equipped with multiple antennas for spectrum sensing. We also assume that each antenna makes fixed number of observations which are used to compute energy metrics. The energy metrics computed at various antennas are then combined using weights determined according to Fisher linear discriminant criterion. In our work we proposed a theoretical framework for change detection of the two hypotheses namely presence (or) absence of PU. From our simulation results we observe that the average detection delay decreases with an increase in the number of observations. The proposed weighted gain combining (WGC) gives lower average detection delay than the equal gain combining (EGC).
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    Study of communication schemes for multiple neural processing nodes
    (Dhirubhai Ambani Institute of Information and Communication Technology, 2015) Mehta, Nilay V.; Mazad, Zaveri
    Over the past few years variety of hardware for implementing Artificial Neural Networks (ANN) has been designed. The most basic approach to speed up any ANN algorithm, is to parallelize processing. However, the existing wired strategies are not easily scalable and are also expensive. This thesis aims to provide low cost, easily scalable architecture for implementation of ANN, targeted for microcontrollers and FPGA architectures. With wired strategies, it is difficult to have scalable architecture with multiple Processing Nodes (PNs). Scalability of the same architecture can be improved by enabling wireless communication between the PNs. In this thesis, different strategies for implementation ofANNhave been analyzed, which considers two different types of PNs (Arduino R and Spartan3E R ) and various communication strategies (I2C with different speeds, Zigbee beacon enabled, Zigbee Non-beacon enabled, Zigbee GTS mode and TDMA scheme). Comparison of all these communication protocols have been carried out in terms of performance (speed) and energy. In this thesis, Nearest-Neighbour-Mesh (NNM) structure for the implementation is considered, where an application consists of 1024 neurons and 1024 synapses per neuron. The analysis has been carried out by varying number of PNs available for implementing this application. For simulation of all the wireless strategies, NS2 (Network Simulator) is used. For estimating computation time for Arduino and Spartan3E, Arduino software (Arduino 1.6.2) and Xilinx ISE Design Suite 14.7 R is used, respectively.
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    Ultra wide band dielectric resonator array antenna
    (Dhirubhai Ambani Institute of Information and Communication Technology, 2015) Rathore, Bhanu Pratap Singh; Ghodgaonkar, Deepak
    Wireless communication play a imported role in our daily life. Present scenario of communication, all wired ones becoming as wireless. So, to achieve efficient and affordable communication in wireless technology, compact and efficient radiators are required. One of the efficient radiators is dielectric resonator antenna (DRA). Almost all the applied power will be lost in the radiated fields only, with this attractive feature DRAs become popular in wireless communication field at microwave frequencies. At high frequency, patch and other metallic antennas have significant amount of energy losses due to conductor which cannot be negligible. Generally, dielectric Resonator antennas have more attractive features compared to general microstrip patch antennas because of absence of conductor material in DR antennas. Dielectric resonating antenna uses a basic type of cavity resonator. It uses various combinations of dielectric materials, different and varied shapes of conducting material, various coupling techniques to produce the desired radiation pattern. In this thesis, DR antenna array is designed with microstrip feed, using High Frequency Simulation Software (HFSS) version 14. The basic design of first antenna which was to be used as a test case for validation of results obtained by the antenna designed in software from a real data set. The second and third antenna which was designed was based on 6.2 GHz band. Its design parameters had two element array mechanisms with dielectric resonator incorporated in every single element separated with a calculated distance to achieve the requisite radiation pattern and desired gain. The only difference was third one was stacked Dielectric Resonator antenna for better coupling and bandwidth improvement purpose. In third arrangement higher permittivity material placed over lower permittivity material because high permittivity material gives better coupling results and low permittivity material gives better Bandwidth.