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 32 for “"PAPR"”.
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Ultraviolet-C Powered Air Purifying Respirator (UVC PAPR)
… a multi-stage powered air-purifying respirator (PAPR) incorporating direct ultraviolet-C (UVC) germicidal irradiation. The proposed PAPR aims to provide enhanced protection by actively sterilizing air through this UVC chamber immediately prior to inhalation. This approach offers an advantage over …
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PAPR reduction in OFDM communications with generalized discrete Fourier transform
… systems is the high Peak to Average Power Ratio (PAPR) value which is directly related to power consumption of the system. Discrete Fourier Transform (DFT) spread OFDM technology, also known as Single Carrier Frequency Division Multiple Access (SCFDMA), which has a lower PAPR value, is used for …
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Spread OFDM via carrier interferometry spreading codes: performance, throughput, and PAPR enhancement
… of performance and Peak-to-Average Power Ratio (PAPR). In this dissertation, the author significantly enhances the performance of traditional OFDM systems via the introduction of novel Carrier Interferometry (Cl) spreading codes. Specifically, this research demonstrates through computer emulation …
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Design, Implementation and Assessment of BPSK and QPSK PAPR over OFDM signals using LimeSDR
… biggest challenge of OFDM multiplexing was high PAPR, which could necessitate expensive circuitry for ADC/DAC components of an SDR solution. OFDM signals were popularly modulated either by Binary Phase Shift Keying (BPSK) or Quadrature Phase Shift Keying (QPSK), which then brought in the question …
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Peak to average power ratio reduction in the orthogonal frequency division multiplexing system using partial transmit sequence
… also. The highest Peak to average power ratio (PAPR) considers the main restrict which cause non-linearity at receiving end. Coding, clipping and phase rotation among many PAPR reduction techniques are proposed to overcome this problem. In this project, we investigated the PAPR reduction …
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An implementation of peak to average power ratio reduction for multicarrier system (orthogonal frequency division multiplexing)
… also. The highest Peak to average power ratio (PAPR) considers the main restrict which cause non-linearity at receiving end. Coding, clipping and phase rotation among many PAPR reduction techniques are proposed to overcome this problem. In this project, we investigated the PAPR reduction …
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Energy-Efficient Multicarrier and Multicarrier-CDMA Systems
… for computation of Peak-to-Average Power Ratio (PAPR). Using extensive simulations, Complementary Cumulative Distribution Functions (CCDFs) of PAPR of OFDM signals for Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), and -QPSK are obtained as a function of number of …
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Evaluation performance of OFDM system using the selected mapping technique for WIMAX technology
… leading to high peak to average power ratio (PAPR). This work, a technique is proposed in the literature for reducing the PAPR in OFDM systems selected mapping technique (SML) for reducing the PAPR in the simulation result shows the PAPR reduction of OFDM signals. The aim is to come up with an …
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Fast peak-power reduction for MIMO-OFDM systems with diversity
… (ACE) reduces the peak-to-average power ratio (PAPR) of single-input single-output (SISO) orthogonal frequency-division modulated (OFDM) signals by extending the outer constellation points in a way that minimizes the PAPR of an OFDM transmit signal, without reducing the bandwidth or increasing …
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New methods of partial transmit sequence for reducing the high peak-to-average-power ratio with low complexity in the ofdm and f-ofdm systems
… However, the high peak-to-average- power ratio (PAPR) is the main obstacle of the OFDM system in the real applications because of the non-linearity nature in the transmitter. Partial transmit sequence (PTS) is one of the effective PAPR reduction techniques that has been employed for reducing the …
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Exploiting Spatial Degrees-of-Freedom for Energy-Efficient Next Generation Cellular Systems
… energy efficiency, peak-to-average power ratio (PAPR) reduction and power amplifier (PA) linearization. Green communication is expected to be a primary goal in next generation cellular systems because it promises to reduce operating costs. The first key issue is energy efficiency of distributed …
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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
… minimization of Peak-to-Average Power Ratio (PAPR) of the time domain Orthogonal Frequency-Division Multiplexing (OFDM)/Cyclic Prefix (CP)-less OFDM signal and reduction of baseband signal Out-of-Band (OOB) spectral power in the vicinity of boundaries of the transmission frequency band is very …
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Generalized DFT: extensions in communications
… Meanwhile, high peak-to-average power ratio (PAPR) is one of the well-known drawbacks of the OFDM system due to reduced power efficiency in non-linear modules. Such a situation leads to inefficient amplification and increases the cost of the system, or increases in interference and signal …
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A hybrid-structure offset-QAM filter-bank multi-carrier MIMO system
… (MIMO) and its high peak-to-average power ratio (PAPR). OQAM/FBMC systems are mainly implemented either using frequency spreading (FS) or polyphase network (PPN) techniques. The PPN technique is generally less complex, but when using frequency domain equalization (FDE) to equalize multipath …
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Generalized discrete Fourier transform with non-linear phase : theory and design
… based communications technique is of its high PAPR at the RF stage of a transmitter. PAPR dominates the power (battery) efficiency of the radio transceiver. Among the PAPR reduction methods proposed in the literature, Selected Mapping (SLM) method has been successfully used in OFDM …
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Design and Implementation of a Constant Envelope OFDM Waveform in a Software-Defined Radio Platform
… examines the high peak-to-average-power ratio (PAPR) problem of OFDM and other spectrally-efficient multicarrier modulation schemes, specifically their stringent requirements for highly linear, power-inefficient amplification. The thesis then presents a most intriguing answer to the PAPR-problem …
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Resource management of cognitive radio networks with optimization methods.
… power (OBP) and the peak-to-average power ratio (PAPR) for non-contiguous orthogonal frequency-division multiplexing (NC-OFDM) systems; (3) Common control channels assignment of cognitive radio networks. MIMO cognitive radio networks adjust the transmit signal covariance matrices. Each secondary …
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Analysis of Wavelet Based Alternatives for OFDM
… We compare the peak to average power ratio (PAPR) for the alternatives. The results show improvement in PAPR for the wavelet based system. That is, the DT-CWT performs the best, then the DWT, and the worst is for the DFT based system.
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NOMA Integrated with Enabling Technologies and Practical Challenges
… for uplink (UL) NOMA, the thesis studies the PAPR problem in UL SCMA-OFDM systems. A novel link between the obtained PAPR statistics and the SCMA modulation scheme and the placement of the sub-carriers (SC’s) that carry the SCMA codewords is presented. The thesis highlights unique …
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Linear Power-Efficient RF Amplifier with Partial Positive Feedback
… signals with high peak-to-average power ratios (PAPR), exhibiting rapid changes in the signal magnitude. To accommodate these high-PAPR signals, RF power amplifiers in mobile devices must operate under backed-off gain conditions, resulting in poor power efficiency. Various efficiency-enhancement …
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