Theses and Dissertations

Permanent URI for this collectionhttp://ir.daiict.ac.in/handle/123456789/1

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Subject: search.filters.subject.Synchronization

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Now showing 1 - 4 of 4
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    FPGA implementation of multiband and multimode modem for software defined radio (SDR)
    (Dhirubhai Ambani Institute of Information and Communication Technology, 2012) Timbadiya, Jaykant; Dubey, Rahul
    Now a days Software Defined Radio(SDR) is becoming popular for wireless communication because of it’s flexibility to change as per requirement through software. The work presented here describes the different methods of designing a Multiband and Multimode MODEM, implementation on programmable device like FPGA and verification for different functionality and specification. The design presented here has ability to switch between different modulation scheme and different data rate. Multiband and Multimode modem includes BPSK and QPSK modulator and demodulator with Forward Error Correction and other base band processing
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    Carrier recovery in software defined radio (SDR)
    (Dhirubhai Ambani Institute of Information and Communication Technology, 2012) Topiya, Vishal N.; Dubey, Rahul
    The work presented here, deals with the carrier synchronization in digital communication system. The transmitter and receiver are two separate circuits located at a distance end and rarely share same carrier frequency oscillator and hence it required to synchronize these two carrier frequency oscillator. This task is performed by the circuit called carrier recovery at receiver end. In this document, different sub modules required to implement carrier recovery structure at receiver end is discussed in detail and each sub module is tested separately using Xilinx® ISE tool. Then these sub modules are used as black boxes, to realize complete carrier recovery structure in Matlab Simulink® tool. By using Matlab Simulink® tool one would get better idea of signal processing at each stage of the carrier recovery structure. Then this complete carrier recovery model of Simulink® is translated to Modelsim® model and verified for functionality. Here this carrier recovery model is used for Software Defined Radio (SDR) application so the complete model of SDR is realized in Matlab Simulink® environment and recovered carrier is used for demodulation part of the SDR
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    Frequency offset estimation in OFDM signals using particle filtering along with resampling methods
    (Dhirubhai Ambani Institute of Information and Communication Technology, 2008) Jayanthi, V. Ravisankar; Vijaykumar, Chakka
    Frequency offset is one of the main effects the Bit Error Rate(BER) in orthogonal frequency division multiplexing (OFDM). There are many applications which depend on OFDM. The present method describes the estimation of frequency offset for OFDM irrespective of the distribution of the channel noise. This method uses Particle Filtering for the estimation of frequency offset. As Particle Filter is a non-linear and non-Gaussian estimator, there will be no constraint on the channel noise. This method also uses the resampling methods, which are essential in modifying the weight approximates during the iterations. Here the performance of the Particle Filter in estimating the frequency offset for the OFDM is observed along with the resampling methods.
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    Orthogonal frequency division multiplexing synchronization techniques
    (Dhirubhai Ambani Institute of Information and Communication Technology, 2008) Ravikanth, Sivangi; Vijaykumar, Chakka
    Synchronization plays a major role in the design of a digital communication system. Essentially, this function aims at retrieving some reference parameters from the received signal that are necessary for reliable data detection. The OFDM is very sensitive to symbol timing and frequency offset. The loss of orthogonality among the subcarriers causes degradation of the OFDM system performance. so, the timing and frequency offset must be estimated and compensated before demodulating the OFDM signals. This report presents the study of different synchronization schemes for OFDM receiver. Different methods like Schmidl-Cox synchronizer, The Coulson synchronizer, The Minn-Zeng Bhargava synchronizer, Blind carrier offset estimation using unused subcarriers etc. Matlab experiments are conducted to study the performance of different synchronization schemes. The simulations results shows that Blind estimation method is more advantage over training symbol and Cyclic Prefix (CP) based methods in terms of Bandwidth saving.