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 26 for “"Flat Fading"”.
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Classification and Parameter Estimation of Asynchronously Received PSK/QAM Modulated Signals in Flat-Fading Channels
… classifier for PSK/QAM modulated signals in flat-fading channels. In developing this classifier, a novel estimator for the unknown channel gain and fractional time delay is proposed which uses a method-of-moments based estimation approach. For the second research thrust of this thesis, the …
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Performance Evaluation of Multiuser Detectors with V-BLAST to MIMO Channel
… detectors over an uplink using AWGN, Rayleigh flat fading single-input single-output (SISO) and multiple-input multiple-output (MIMO) channel models. First, we review the performance of three multiuser receivers; the decorrelator, the MMSE receiver and the multistage parallel interference …
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I/Q imbalance mitigation for space-time block coded communication systems
… by exploiting the spatial diversity in fading channels. However, due to component imperfections, the in-phase/quadrature (I/Q) imbalance caused by the non-ideal matching between the relative amplitudes and phases of the I and Q branches always exists in the practical implementation of …
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Resource allocation in realistic wireless cognitive radios networks
… the performance of realistic channel models with fading. This is of key importance as simple additive white Gaussian noise channels are generally not very realistic and tend to yield overly optimistic results. Hence the proposed solution develops a realistic non-cooperative power control game to …
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Analysis on the use of EM algorithm for space time coding in fading channels
… method of partial detected frame in slow, flat fading channel, it is found that the use of partial frame to estimate the mean is able to improve the EM algorithm further. In the study, the use of a minimum 2 symbols results in a BER performance improvement of 2dB as compared to the use of …
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Channel Prediction for Adaptive Modulation in Wireless Communications
… includes simulations in slow and moderately fast flat fading Rayleigh channels. We present our findings regarding the advantages of using predictive measures to foresee the state of the channel and make adjustments to transmissions accordingly. In addition to finding the general advantages of …
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Performance Study of OFDM over Fading Channels for Wireless Communications
… are additive white Gaussian noise (AWGN) and fading channels. Each channel affects the process of transmission in a certain way. Simulation results will make us understand some of these effects.</p> <p>Fading channels include two types of flat fading and two types of frequency selective …
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Harvesting time-frequency-space diversity with coded modulation for underwater acoustic communications
… white Gaussian noise (AWGN) and Rayleigh fading channels (and, consequently in the Rice fading channel, an intermediate channel model between the latter two). Hence, high data-rate coded modulation schemes should exhibit both large free Euclidean and Hamming distances. In addition, coded …
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A Model-Based Receiver for CPM Signals in a Cochannel Interference Limited Environment
… non-coherent receivers for MSK with AWGN, flat fading, and CCI. Demodulator diversity is also investigated as a way to combat interference. An improved technique combining the proposed model-based receiver and the conventional coherent receiver is implemented and simulated in presence of …
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Modeling and Analysis of Synchronization Schemes for the TDMA Based Satellite Communication System
… its high bandwidth efficiency and robustness to fading. As is known, accurate synchronization is a key requirement for efficient data transmission in TDMA systems. Because of the channel impairment or propagation delay, the receiver may experience the carrier frequency offset (CFO) or symbol …
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Iterative Techniques Based on Energy Spreading Transform for Wireless Communications
… algorithms for communication systems over fading channels. They include channel equalization to combat intersymbol interference (ISI) and multiple input multiple output (MIMO) signal detection to deal with multiple access interference (MAI) from other transmit antennas. As the demand for …
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Feasibility of Smart Antennas for the Small Wireless Terminals
… developments and performance evaluations in both flat fading and frequency selective channels. Practical issues, i.e., latency and amount of feedback, related to transmit smart antenna operation are discussed. Various channel measurements are presented to assess the performance of a transmit smart …
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Wavelet Modulation in Gaussian and Rayleigh Fading Channels
… modulation; BER versus SNR curves for each fading channel show how the message at one rate can be more accurately recovered than at another rate. Furthermore, we also present results indicating the dramatic improvement in wavelet demodulation performance when multiple rates are available and …
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Resource allocation and physical layer security in wireless communication systems
… user selection algorithm is presented for the flat-fading channel, when zero-forcing beamforming is employed at the BS and the aim is to maximize system's throughput. For the more interesting case where the transmission is performed simultaneously over a number of parallel subchannels, two …
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Adaptive signal combining and detection in cooperative wireless networks
… and Decode-and-Forward cooperative protocols in flat fading Rayleigh wireless channels. 2. Adaptive signal combining was proposed for cooperative wireless networks and its performance was analysed by using Least Mean Square and Recursive Least Square algorithms. The other classical non-adaptive …
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Spectrum Sensing in the Presence of Channel and Tx/Rx Impairments
… signals (PAM, PSK, QAM, ...) in slowly-varying flat-fading channels. Based on this work, research is then presented on a feature-based modulation classification approach which relaxes the requirements of perfect frequency synchronization and knowledge of the phase information of the received …
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Fractionally Spaced Blind Equalizer Performance Improvement
… investigated by predicting the envelope of a flat fading channel under constant mobile velocity and constant acceleration conditions.
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Simulation of Adaptive Array Algorithms for OFDM and Adaptive Vector OFDM Systems
… multipaths are present in this environment and fading is not highly correlated across the band. Orthogonal frequency division multiplexing (OFDM) is well-known to be effective against multipath distortion. It is a multicarrier communication scheme, in which the bandwidth of the channel is …
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Empirical Approch For Rate Selection In MIMO OFDM
… The channels can be viewed as parallel flat fading channels for which the expected BER rate can be computed. A SNR-BER table is used to efficiently compute the performance efficiently. An effective SNR is computed using the table and compared with rate threshold to select a suitable …
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Hybrid Orthogonal Code Sequences for High-Density Synchronous CDMA Systems
… and orthogonal m-sequence under Rayleigh flat and frequency selective fading channel conditions while having a significantly higher capacity than those orthogonal code sequences. The proposed HOVLS code sequence could support 134 different cells which is more than twice than that of …
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