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 35 for “"Rayleigh Fading Channel"”.
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Coding and multiaccess for the energy limited Rayleigh fading channel
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1988.
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The impact of Rayleigh fading channel effects on the RF-DNA fingerprinting process
… that estimates the coefficients of an indoor Rayleigh fading channel. The performance of the Nelder-Mead estimator is compared to the Least Square estimator and is assessed with degrading signal-to-noise ratio. The Rayleigh channel coefficients set estimated by the Nelder-Mead estimator is …
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Adaptive DS-CDMA multiuser detection for time variant frequency selective Rayleigh fading channel
… systems over time-variant frequency selective fading channels. In addition, channel acquisition and delay estimation techniques are developed to combat the uncertainty introduced by the wireless propagation channel. This work emphasizes fast and simple techniques that can meet practical needs …
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Performance Evaluation of Cognitive Radio Spectrum Sensing Techniques through a Rayleigh Fading Channel
… of these spectrum-sensing techniques through a Rayleigh fading channel. In a wireless environment, a Rayleigh fading channel models the propagation of a wireless signal where there is no dominant line of sight between the transmitter and receiver. Understanding the performance of spectrum …
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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
… for analyzing two-branch diversity systems for a Rayleigh fading channel. In many cases the fading received at both branches (i.e. a two-antenna element system) is correlated because of the proximity of the antenna elements to each other. It is also not uncommon for a diversity system to use …
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Noncoherent Communication Over Fading Channels
… communication scenario. For a Gauss-Markov Rayleigh fading channel, we derive upper and lower bounds for the mutual information generated by the Gaussian input distribution. The upper bound shows that the mutual information remains bounded at high SNR. We obtain necessary and sufficient …
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Improved successive interference cancellation schemes using selective pre-cancellation and cross- correlation
… capacity improvements up to 100% in an AWGN channel and 26% in a Rayleigh fading channel compared to a SIC without the improvements. This is achieved with minimal additional computation complexity and processing time.
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Simulation and Estimation Techniques for Wideband High-Frequency Communication Channels
A technique for estimating the channel multipath parameters for wideband high frequency (WBHF) communication systems is analyzed. To explore the technique, a WBHF communication system is simulated in software using three new channel models. One channel model is based on a simulation of wave …
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Bit error rate simulation enhancement and outage prediction in mobile communication systems
… systems. Internally generated two-ray Rayleigh fading channel models as well as imported spatially varying complex channel impulse responses can be utilized in simulations. Implementation of receiver timing jitter and timing recovery models, as well as modifications of the channel …
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Performance evaluation of communication systems with transmit diversity
Transmit diversity is a key technique to combat fading with multiple transmit antennae for next-generation wireless communication systems. Space-time block code (STBC) is a main component of this technique. This dissertation consists of four parts: the first three discuss performance evaluation of …
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Error and erasure decoding for a CDPD system
… telephone network to transmit data with a channel hopping technique. The CDPD system employs Gaussian minimum shift keying (GMSK) as a modulation scheme and a Reed-Solomon code for error control to transmit high-quality data in the mobile and wireless environment. Most current CDPD …
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A new hybrid acquisition scheme for CDMA systems employing short concatenated codes
… Finally the simplified model is studied in a Rayleigh fading channel.
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Adaptive, Turbo-coded OFDM
… error correction (FEC) methods over wireless channels. In this thesis, we enhance the system throughput of a working OFDM system by adding turbo coding and adaptive modulation (AD). Simulation is done over a time varying, frequency selective Rayleigh fading channel. The temporal variations in …
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Combined Space-Time Diversity and Interference Cancellation for MIMO Wireless Systems
… of multiple-input and multiple-output (MIMO) channels to enhance the capacity of wireless systems. In this study, we develop and evaluate a channel model, evaluate the corresponding channel capacity, and design and analyze a simple orthogonal transmit waveform for MIMO channels in mobile radio …
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Concatenation of Space-Time Block Codes with ConvolutionalCodes
… help in combating the destructive effects of fading as well as improve the spectral efficiency of a communication system. Receive diversity techniques like maximal ratio receive combining have been popular means of introducing multiple antennas into communication systems. Space-time block …
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DSP implementation of trellis coded modulation and distributed space time coding
… from multiple antennas at the same time over a Rayleigh fading channel. STC combines of transmit diversity, coding and M-ary modulation to mitigate problems imposed by the fading channel, Two types of STC, space time coded modulation (STCM) and block STC, are discussed in this thesis. …
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Simulation of adaptive equalization in two-ray, SIRCIM, and SMRCIM mobile radio channels
… because of their better performances. A two-ray Rayleigh fading channel model is used to simulate the mobile channels. The results show that adaptive equalization can significantly improve the performance of mobile communications if the channel does not change too fast. The simulation shows that …
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Implementation and evaluation of various stop and wait type II hybrid ARQ schemes for mobile radio
… and numerically analyzed in both an AWGN channel and a combined AWGN and Rayleigh fading channel. The three variations of the general scheme implemented are: Rate 3/4 CPC SW Type II ARQ, Rate 3/4CPC SW Type II ARQ with Code Combining, and an Adaptive CPC SW Type II ARQ scheme. The …
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Channel-predictive link layer ARQ protocols in wireless networks
Communication performance over a wireless channel should be considered according to two main parameters: energy and throughput. The reliable data transfer is a key to these goals. The reliable node-to-node data transfer is performed by link layer protocols. One prominent approach is Automatic …
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