Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"constant modulus"”.
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Simulation of Adaptive Array Algorithms for CDMA Systems
… and least-squares despread respread multitarget constant modulus algorithm (LS-DRMTCMA), are developed, and a MATLAB simulation testbed is created to compare the performance of these two novel algorithms with those of the multitarget least-squares constant modulus algorithm (MT-LSCMA) and …
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Generalized discrete Fourier transform with non-linear phase : theory and design
Constant modulus transforms like discrete Fourier transform (DFT), Walsh transform, and Gold codes have been successfully used over several decades in various engineering applications, including discrete multi-tone (DMT), orthogonal frequency division multiplexing (OFDM) and code division multiple …
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Equalization Techniques For Multipath Mitigation in Aeronautical Telemetry
… of adaptive equalization based on the constant modulus algorithm (CMA) and the decision-feedback minimum mean squared error (DF-MMSE) concept to the two compatible offset QPSK waveforms (FQPSK and SOQPSK-TG) that constitute the ARTM Tier-1 waveforms. An adaptive version of the DF-MMSE …
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Blind adaptive antenna arrays for mobile communications
… of three blind adaptive algorithms: the Constant Modulus Algorithm (CMA), the Spectral self-COherence Restoral Algorithm (SCORE), and the spectral correlation predictor using a Time-Dependent Adaptive Array (TDAA), are studied. The TDAA is introduced as a new blind algorithm that exploits …
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PAPR reduction in OFDM communications with generalized discrete Fourier transform
… is its ability to design a wide selection of constant modulus orthogonal code sets, based on the desired performance metrics mimicking the engineering specs of interest. One of the main drawbacks of Orthogonal Frequency Division Multiplexing (OFDM) systems is the high Peak to Average Power …
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Fast blind adaptive equalisation for multiuser CDMA systems
… algorithms, or on blind adaptation, such as the Constant Modulus Algorithm (CMA) or the Decision Directed algorithm (DD), which has similar convergence properties as the LMS in the absence of decision errors, the CMA is relatively slow compared to the DD algorithm but more robust in converging to …
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Direction of arrival estimation using antenna arrays
… as the Iterative Least Squares Projection-based Constant Modulus Algorithm (lLSP-CMA) with subspace-based techniques. All these algorithms were simulated in MATLAB and their performance under different conditions were tested and compared. In the second phase of the project a six element uniformly …
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An eigenstructure technique for direct sequence spread spectrum synchronization
… signal. It is applicable to DSSS signals with a constant modulus code and requires the knowledge of only the code repetition rate. The technique is robust to multiple access interference provided the users have different code repetition rates.
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Analysis and Development of Blind Adaptive Beamforming Algorithms
… here is shown to include the well-known Constant Modulus Algorithm (CMA) and decision directed algorithm (DDA). New results on the behavior of the CMA and DDA are presented here, including analytic results on the convergence rate. Previous results have relied on Monte Carlo simulation. …
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Techniques and adaptation algorithms for direct-sequence spread-spectrum CDMA single-user detection
… algorithm, and the linearly constrained constant modulus algorithm (LCCMA ). Through simulation, a blindly-adapted single-user detector is shown to greatly outperform the conventional receiver in terms of bit-error-rate (BER) performance, and to perform almost as well as in the case of …
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A CMA-FRESH Whitening Filter for Blind Interference Rejection
… property restoration algorithm, inspired by the constant modulus algorithm (CMA), is applied to each frequency bin to determine the optimal coefficients for the proposed CMA FRESH whitening filter (CFW). The performance of the CFW in interference rejection is compared to a time-invariant version, …
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A new sufficient-order blind equalization scheme
… and for the adaptation of the FIR filter, a constant modulus adaptive algorithm is proposed. It is shown that the proposed blind equalization scheme requires a substantially less amount of computations and is easy to implement. The proposed sufficient-order blind equalization scheme is …
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Fractionally Spaced Blind Equalizer Performance Improvement
… commonly used blind adaptation algorithm is the Constant Modulus Algorithm (CMA). It is shown by simulation that a logarithmic error equation can make CMA converge to a global minimum, if a differential encoding scheme is used. The performance of CMA with different error equations is also …
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A Novel Material Modulus Function for Modeling Viscoelastic Materials
… into finite element models. In metals, the modulus of elasticity can be modeled as a constant. That is, the modulus of elasticity is not treated as a function of frequency in dynamic models. For viscoelastic materials, the modulus of elasticity can be assumed to be constant for static forces …
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Adaptive polarization mode dispersion equalizers for coherent optical communications systems
… adaptive electronic equalizers, based on the constant modulus algorithm (CMA) equalizers perform slightly better than the decision directed least mean square (DD-LMS) counterparts at links with larger PMD values, whereas the opposite holds true for the low PMD regime. Due to their …
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Array Signal Processing Algorithms for Beamforming and Direction Finding
… minimum variance (CMV) and the constrained constant modulus (CCM) criteria to propose full-rank and reduced-rank adaptive algorithms. Specifically, for the full-rank algorithms, we present two low-complexity adaptive step size mechanisms with the CCM criterion for the step size adaptation of …
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Design and Optimization of Physical Waveform-Diverse and Spatially-Diverse Radar Emissions
… for radar waveform design. Constraints such as constant amplitude (to maintain sufficient power efficiency) and continuous phase (for spectral containment) are still considered prerequisites for high-powered radar waveforms. These criteria are also applicable to the design of multiple waveforms …
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Advanced Interference Suppression Techniques for Spread Spectrum Systems
… Firstly we investigate blind constrained constant modulus (CCM) stochastic gradient (SG) receivers with a low-complexity variable step-size mechanism for downlink direct sequence CDMA (DS-CDMA) systems. This algorithm provides better performance than existing blind schemes in …
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Adaptive interference suppression algorithms for DS-UWB systems
… receiver based on JIO and the constrained constant modulus (CCM) design criterion is proposed that offers higher spectrum efficiency. Adaptive implementations for the blind JIO receiver are developed by using the normalized stochastic gradient (NSG) and RLS algorithms. In order to obtain a …
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Blind multidimensional matched filtering for wireless channelswith multiple antennas
… makes use of an adaptive algorithm, i.e. the Constant Modulus Algorithm (CMA), to estimate the channel without the need for an implementation inefficient approach as stated above. The BMF method assumes that the receiver utilizes channel matched filtering before the equalization of the …
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