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 39 for “"Peak to average power ratio"”.
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An implementation of peak to average power ratio reduction for multicarrier system (orthogonal frequency division multiplexing)
… (LTE) which depended from the fourth-generation (4G) of wireless communication system. OFDM proves high efficiency to transmit data rate as high as 100 Mbps, the capability to combat multipath fading channel and utilization the whole bandwidth. Although, OFDM technology has more …
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Peak to average power ratio reduction in the orthogonal frequency division multiplexing system using partial transmit sequence
… (LTE) which depended from the fourth-generation (4G) of wireless communication system. OFDM proves high efficiency to transmit data rate as high as 100 Mbps, the capability to combat multipath fading channel and utilization the whole bandwidth. Although, OFDM technology has more …
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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
… high-speed wireless standards. 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 …
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Peak power reduction in orthogonal frequency division multiplexing transmitters
… is a digital transmission method developed to meet the increasing demand for higher data rates in communications which can be used in both wired and wireless environments. This thesis describes the issue of the Peak to Average Power Ratio (PAPR) in OFDM which is a major drawback, and …
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Broadband and Energy-Efficient Power Amplifier Architectures
In this dissertation, power amplifier circuits and architectures are proposed that provide high efficiency for spectral-efficient high peak-to-average power ratio signals that are being used in modern communications systems. Using the proposed amplifier architectures and circuits high efficiency …
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New Techniques for Multicarrier Communication Systems
Common to all OFDM systems is a large peak-to-average-power ratio (PAR) problem, which can lead to low power efficiency and nonlinear distortion at the transmit power amplifier. Tone reservation uses unavailable or reserved tones to design a peak-cancelling signal that lowers the PAR of a transmit …
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Spread OFDM via carrier interferometry spreading codes: performance, throughput, and PAPR enhancement
… since the 1970's and 1980's. OFDM is now the protocol in the IEEE 802.11a and IEEE 802.1 lg Wireless Local Area Networks (WLANs) standards, as well as the IEEE 802.16 Fixed Broadband standard. It is also a front-runner for implementation in future cellular standards and satellite systems. …
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PAPR reduction in OFDM communications with generalized discrete Fourier transform
… Discrete Fourier Transform (GDFT) is its ability to design a wide selection of constant modulus orthogonal code sets, based on the desired performance metrics mimicking the engineering specs of interest. One of the main drawbacks of Orthogonal Frequency Division Multiplexing (OFDM) systems is the …
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Evaluation performance of OFDM system using the selected mapping technique for WIMAX technology
… with high spectral efficiency, robustness to channel fading, immunity to impulse interference, uniform average spectral density, capacity to handle very strong echoes and very less nonlinear distortion are the properties of the OFDM. One major disadvantage of OFDM is that the time domain …
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Analysis of Wavelet Based Alternatives for OFDM
The objective of this thesis is to analyze wavelet based alternatives for orthogonal frequency division multiplexing (OFDM) and find whether a better system performance is achieved when compared to the discrete Fourier transform (DFT)-based OFDM. We analyze DFT, discrete wavelet transform (DWT), …
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Sistemas de transmissão multiportadora aplicados em um canal acústico submarino na presença de efeito doppler
… rate, has also the motivation of reducing the peak-to-average power ratio (PAPR). The performance of these systems is assessed through the relation between signal to noise ratio (SNR) and bit error rate. The applicability of filterbank based transceivers with reduced redundancy in each block in …
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Digitally enhanced CMOS RF transmitter with integrated power amplifier
… RF transmitter with integrated 23 dBm, Class-B power amplifier (PA) is fabricated in a 0.13 μm CMOS process. The TX chip is packaged using a low-cost chip-on-board (COB) technique. When 20-MHz bandwidth OFDM signals are transmitted, a high TX average power efficiency is achieved exploiting the …
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Optimal nonlinear digital signal processing : a dynamical systems approach
… digital signal processing problems aimed to improve power efficiency of modern wireless transmission systems. The first part of this thesis is motivated by peak-to-average power ratio reduction of communication signals. The problem is formulated as minimization of a frequency-weighted …
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The Bit Error Rate (BER) Performance in Multi-Carrier (OFDM) and Single-Carrier
… spectacular growth of wireless communication tools has escalated the number of mobile subscribers from almost 700 million in 2000 to more than 4 billion in 2009. The huge number of subscribers has led to several issues with how service is provided. The high user demand has forced developers to …
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Design and Implementation of a Constant Envelope OFDM Waveform in a Software-Defined Radio Platform
This thesis 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 …
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AC Power Combining Strategy with Application to Efficient Linear Power Amplifiers
<p>With the ongoing push for wireless systems to accommodate more users and support higher data rates more efficient modulation schemes have been created that are more advanced than simple FM and AM modulation used for radio broadcasting. These modulation schemes, such as orthogonal frequency …
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Investigation and Design of New, Efficient and Compact Load Modulation Amplifiers for 5G Base Stations. Design, Simulation, Implementation and Measurements of Radio Frequency Power Amplifiers Using Active Load Modulation Technique for More Compact and Efficient 5G Base Stations Amplifiers
… with full retention of system performance. The power amplifier in modern mobile communications system consumes most of the supplied power through the dissipated power and the required cooling systems. However, as new services were added as features for the developed mobile generations, the …
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Resource management of cognitive radio networks with optimization methods.
… channel usage so that the induced interference to the licensed user is regulated. The dissertation focuses on solving three kinds of problems of the cognitive radio networks: (1) Multiple-input and multiple-output (MIMO) transmission of cognitive radio networks; (2) Joint reduction of the …
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Fast peak-power reduction for MIMO-OFDM systems with diversity
A robust peak-power reduction technique called active constellation extension (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 …
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Energy-Efficient Multicarrier and Multicarrier-CDMA Systems
… and iii) Selective Mapping (SLM) and Tone Reservation (TR) with reduced complexity. These methods are described and algorithms are presented for computation of Peak-to-Average Power Ratio (PAPR). Using extensive simulations, Complementary Cumulative Distribution Functions (CCDFs) of …
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