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 “"Maximal Ratio"”.
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Analysis of a Two-Branch Maximal Ratio and Selection Diversity System with Unequal Branch Powers and Correlated Inputs for a Rayleigh Fading Channel
… in differences in average signal-to-noise ratios at both branches depending on which element is better matched to the signal environment. As will be shown, the performance of a diversity system depends greatly on the envelope correlation, average power imbalance and the combining scheme …
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Concatenation of Space-Time Block Codes with ConvolutionalCodes
… system. Receive diversity techniques like maximal ratio receive combining have been popular means of introducing multiple antennas into communication systems. Space-time block codes present a way of introducing transmit diversity into the communication system with similar complexity and …
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Performance evaluation of massive MIMO Systems for future wireless access systems
… generally not optimal. Optimal methods such as Maximal Likelihood (ML) signal processing methods have high computational complexity such that their practical implementation is difficult. The complexity for ML is O(MN ) for an M−ary modulated signal and N antennas. This is compared to a linear …
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Four Branch Diversity Combining and Adaptive Beamforming Measurements Using Mobile Arrays at 2.05 GHz
… of four element arrays with different configurations and with different element patterns is compared using the square array of four half-wave dipole elements as the baseline. Results from diversity and beamforming measurements, performed in urban and suburban environments for both …
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Improving the Performance of Wireless Systems via Selective Interference Nulling and Adaptive Medium Access Control Design
… using selective interference nulling (SIN) and maximal ratio combining (MRC) in mobile radio environments is developed. In the second part of this thesis, we explore the performance gains that can be achieved by exploiting the synergy resulting from the combination of the MAC and the physical …
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Adaptive signal combining and detection in cooperative wireless networks
… The other classical non-adaptive techniques Maximal Ratio Combining and Wiener were also examined. It was also shown that adaptive signal combining achieves Wiener's solution in cooperative wireless networks with added benefit of computational simplicity over classical combining schemes. 3. …
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Performance Evaluation of Equal Gain Diversity Systems In Fading Channels
Next generation wireless systems are being designed to provide ubiquitous broadband link access to information infrastructure. Diversity techniques play a vital role in supporting such high speed connections over radio channels by mitigating the detrimental effects of multiuser interference and …
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Phase-locked loop, delay-locked loop, and linear decorrelating detector for asynchronous multirate DS-CDMA system
… we propose Hybrid Selection Diversity/ Maximal Ratio Combining (Hybrid SD/MRC) one-shot window linear decorrelating detector (LDD) for asynchronous DS-CDMA systems. The selection diversity scheme at the input of the Hybrid SD/MRC LDD is based on choosing the branch with the maximum …
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Smart Base Station Antenna Performance for Several Scenarios - an Experimental and Modeling Investigation
… diversity methods with selection combining (SC), maximal ratio combining (MRC), and equal gain combining (EGC) techniques for both urban and suburban non-line-of-sight (NLOS) environments are presented and summarized using the measured data. Forward-link performance of a twelve-fixed narrow-beam …
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Practical packet combining for use with cooperative and non-cooperative ARQ schemes in wireless sensor networks
… 2.5 dB reduction in the required Signal-to-Noise ratio (SNR) for a particular Packet Error Rate (PER). This is a welcome result as complex schemes, such as maximal-ratio combining, are not implementable on many of the resource constrained devices under consideration. A motivational side study on …
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Spectrum sensing, spectrum monitoring, and security in cognitive radios
… formulate and solve the generalized likelihood ratio test (GLRT) for spectrum sensing when both primary user transmitter and the secondary user receiver are equipped with multiple antennas. We do not assume any prior information about the channel statistics or the primary user’s signal …
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Universal codes for parallel Gaussian channels
… it saturates. We find an expression for this saturation efficiency. We show that partial CSIT improves the efficiency significantly. At the end we compare the performance of maximal ratio combining (MRC) and MMSE receivers and show that they are close in the coding scheme with no CSIT. In Chapter …
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Implementing IS-95, the CDMA standard, on TMS320C6201 DSP
IS-95 is the present U.S. 2nd generation CDMA standard. Currently, the 2nd generation CDMA phones are produced by Qualcomm. Texas Instruments (TI) has ASIC design for Viterbi Decoder on C54x. Several of the components in the forward link process are also implemented in hardware. However, having to …
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Cooperative diversity aided direct-sequence code-division multiple-access systems
… the dependence of the achievable bit error ratio (BER) performance of DS-CDMA systems on the specific locations of the relays as well as on the power-sharing among the source transmitters and relays, when considering different propagation path loss exponents.<br/>This thesis is focused on …
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Smart Antennas at Handsets for the 3G Wideband CDMA Systems and Adaptive Low-Power Rake Combining Schemes
… incorporated into handsets for the third generation wireless personal communication systems in which the two antennas are separated by a quarter wavelength (3.5 cm). We examine the effectiveness of a dual smart antenna system with diversity and adaptive combining schemes and propose a new …
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Advanced methods in automatic modulation classification for emerging technologies
… performance. Although the average likelihood ratio test method can provide an optimal solution to the MC problem with unknown parameters, it suffers from high computational complexity and in some cases mathematical intractability. Instead, in this research, an array-based quasi-hybrid …
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Space Time Processing for Third Generation CDMA Systems
… the world are working to introduce the third generation (3G) cellular service that will provide higher data rates and better spectral efficiency. Wideband CDMA (WCDMA) has been widely accepted as one of the air interfaces for 3G. A Beamformer-Rake receiver can be an effective solution to provide …
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Time Diversity Modelling and Implementation for Broadcast Satellite Systems at V-band
… diversity (TD) as a highly promising link restoration scheme that makes for efficient use of higher frequency bands without imposing unrealistically high fixed propagation margins on the satellite link.Accurate knowledge of rain attenuation distribution is necessary for a proper design of a TD …
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Doppler spread estimation in mobile fading channels
… diversity schemes, selection combining (SC) and maximal ratio combining (MRC), are considered for Doppler spread estimation. Four new estimators are derived which rely on the inphase zero crossing rate, inphase rate of maxima, phase zero crossing rate, and the instantaneous frequency zero …
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