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 30 for “"Quadrature amplitude modulation"”.
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PAPR reduction in OFDM communications with generalized discrete Fourier transform
… systems for Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK) and 16 Quadrature Amplitude Modulation (16-QAM), digital modulation techniques are increased.
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Physical layer DSP design of a wireless gigabit/s indoor LAN
… Multiplexing (OFDM) with adaptive multilevel Quadrature Amplitude Modulation (M-QAM). The proposed network design allows two-way communication through a Time Division Duplexing (TDD) scheme and provides multiuser support through a series of algorithms that establish session links and allocate …
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Novel predistortion techniques for RF power amplifiers
… are applied to both two-tone tests and 16 QAM (Quadrature Amplitude Modulation) signals. The test power amplifiers vary from class A, inverse class E, to cascaded amplifier systems. Our experiments have demonstrated that these new predistortion techniques can reduce the upper and lower sideband …
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Design and analysis of a high-rate acoustic link for underwater video transmission
… acoustic modems based on phase coherent modulation/detection have demonstrated successful transmission at 30 kbps over a deep water channel. The key to bridging the remaining gap between the bit-rate needed for video transmission and that supported by the acoustic channel lies in two …
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GRAND-assisted Optimal Modulation
… peak and average power constraints the optimal modulation (OM) schemes are known to have nonuniform probability distributions over the signal points. An established way to obtain these distributions is assigning different number of bits to different constellation points. However, this method …
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Machine Learning-Based Receiver in Multiple Input Multiple Output Communications Systems
… include the shifting invariant property of quadrature amplitude modulation, the time-frequency relation inherent in OFDM signals, the multi-mode feature of massive antennas, and the delay-Doppler representation of doubly selective channel. In addition, the neural network structures are …
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Experimental demonstration of cap transmitter using very high speed IC hardware description language (VHDL)
Carrierless Amplitude Phase (CAP) Modulation is a multidimensional and multilevel of modulation scheme which it is strongly inspired by QAM modulation scheme. CAP does not depend on a carrier and it is much simpler. Lots of CAP modulation experiments have been proposed and demonstrate but none of …
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A FPGA/DSP based ultrasound system for tumor detection
… 1uS. This work elaborates the implementation of Quadrature Amplitude Modulation (QAM) receiver on FPGA for received signal from ultrasound detector. LTP is applied to the tumor samples through the transmitter and the received signal at ultrasonic receiver is passed through QAM to get different …
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Adaptive multilevel quadrature amplitude radio implementation in programmable logic
… are increasingly employing spectrally efficient modulation methods like Quadrature Amplitude Modulation (QAM) to increase the channel efficiency and maximize data throughput. Unfortunately, the performance of high level QAM modulations in the wireless channel is sensitive to channel imperfections …
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Fast all-digital carrier synchronization techniques for linear modulation formats
… based on oversampling, suitable for linear modulation schemes ( M -ary phaseshift-keying ( M -PSK) and M -ary quadrature amplitude modulation ( M -QAM)). Carrier synchronization is studied because, in passband communications, carrier phase and frequency offsets, due to modem oscillator …
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Design and Analysis of OFDM System for Powerline Based Communication
… environments. Coupled with advances in new modulation techniques, Orthogonal Frequency Division Multiplexing (OFDM) is a well-known digital multicarrier communication technique and one of the best methods of digital data transmission over a limited bandwidth. The main aim of this research is …
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Power allocation and linear precoding for wireless communications with finite-alphabet inputs
… inputs such as phase-shift keying (PSK), pulse-amplitude modulation (PAM), and quadrature amplitude modulation (QAM) signals. This approach, without the commonly used Gaussian input assumptions, complicates the mutual information analysis and precoder design but improves performance when the …
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Error relilient video communications using high level M-QAM. Modelling and simulation of a comparative analysis of a dual-priority M-QAM transmission system for H.264/AVC video applications over band-limited and error-phone channels.
… investigation of an M level (M = 16, 64 and 256) Quadrature Amplitude Modulation (QAM) transmission system suitable for video transmission is presented. The communication system is based on layered video coding and unequal error protection to make the video bitstream robust to channel errors. An …
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Implications of Fiber Nonlinearities on Coherent Optical Fiber Communications
… this target by increasing the cardinality of modulation formats is at the expense of a reduced system tolerance to transmission impairments with the capacity ultimately limited by Kerr fiber nonlinearities. The research presented in this thesis focuses on exploring solutions to fulfill the …
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Developing microwave probes for investigating opto-electronic processes in photovoltaic materials
… shaped pulses for EPR; b) design a custom-built quadrature-amplitude modulation instrument to implement shaped pulses into an existing Bruker E580 spectrometer; and c) demonstrate an increased sensitivity of the Rabi frequency spectroscopy technique using shaped pulses applied to P3TP, a …
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Advanced Orthogonal Frequency-Division Multiplexing Systems with Cyclic Prefix-Less Multiple-Input and Multiple-Output Discrete Fourier Transform Spreading and Unmanned Aerial Vehicles-Assisted Cyclic Postfixed Windowed Schemes
… Ratio (SNR), Eb/N₀ = 15 dB with 16-Quadrature Amplitude Modulation (16-QAM) modulation. To improve the spectral efficiency and robustness of wireless communication systems, on the other hand, drone-assisted 5G and beyond 5G wireless communication networking capabilities require …
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A hybrid-structure offset-QAM filter-bank multi-carrier MIMO system
Offset quadrature amplitude modulation (OQAM) filter-bank multi-carrier (FBMC), has great potential for boosting the spectral efficiency (SE) and energy efficiency (EE) of future communication systems. This is due to its superior spectral localization, CP-less transmission and relaxed …
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On the Impact of Channel and Channel Quality Estimation on Adaptive Modulation
… wireless systems are designed by choosing a modulation scheme to meet worst case conditions and thus rely on power control to adapt to changing channel conditions. Adaptive modulation, however, exploits these channel variations to improve the spectral efficiency of wireless communications by …
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Facilitating Wireless Communications through Intelligent Resource Management on Software-Defined Radios in Dynamic Spectrum Environments
… multiplexing (OFDM) using offset quadrature amplitude modulation (OFDM/OQAM) which is shown to have significant spectral compactness advantages over traditional OFDM. Demodulation of OFDM/OQAM is accomplished using computationally effcient polyphase analysis filterbanks, enabled by …
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Orthogonal Frequency Division Multiplexing Modelling
… 5th Generation (5G) and beyond. One of the modulation strategies for upcoming 5G mobile communication technologies is FBMC. When compared to OFDM, which is utilised in Fourth Generation (4G) mobile communications technology, it employs multicarrier techniques that are immune to fading …
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