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Envelope Tracking Power Amplifiers For Wireless Communications
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Book Synopsis Envelope Tracking Power Amplifiers for Wireless Communications by : Zhancang Wang
Download or read book Envelope Tracking Power Amplifiers for Wireless Communications written by Zhancang Wang and published by Artech House. This book was released on 2014-06-01 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: Envelope tracking technology is seen as the most promising efficiency enhancement technology for RF power amplifiers for 4G and beyond wireless communications. More and more organizations are investing and researching on this topic with huge potential in academic and commercial areas. This is the first book on the market to offer complete introduction, theory, and design considerations on envelope tracking for wireless communications. This resource presents you with a full introduction to the subject and covers underlying theory and practical design considerations.
Book Synopsis High Efficiency Wideband Envelope Tracking Power Amplifier for Next-generation Wireless Communications by : Myoungbo Kwak
Download or read book High Efficiency Wideband Envelope Tracking Power Amplifier for Next-generation Wireless Communications written by Myoungbo Kwak and published by . This book was released on 2011 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: The latest generation of smart devices deployed in cellular networks has created explosive growth in network data traffic, and the increasing demand for broadband services with higher data rates, require higher peak to average power ratio (PAPR) with wider bandwidth. One of the challenges in the conventional power amplifiers (PAs) with fixed supply voltage, is the degraded efficiency and generated heats at a large back-off to meet tight linearity requirements. This dissertation presents high efficiency wideband envelope tracking power amplifiers for 2.1 GHz micro base-stations and 2.5 GHz wireless mobile applications. By superimposing the envelope signal at the drain such that the RF amplifier operates consistently closer to saturation, the overall efficiency is improved and the generated heat is reduced dramatically. In the first part of the dissertation, a high performance BiCMOS DMOS monolithic envelope amplifier for micro-base station power amplifiers is presented. Due to the low breakdown voltage of the CMOS transistors, the high voltage envelope amplifier has been implemented with discrete components with high voltage process. Compared to these discrete solutions, an integrated circuits implementation for the envelope amplifier brings many benefits. The design of monolithic envelope amplifiers for high voltage (VDD = 15 V) envelope tracking applications, and the design techniques to solve the reliability issues with thin gate oxide is described. The overall envelope tracking system employing a GaN-HEMT RF transistor, and fully integrated high voltage envelope amplifier with a 0.35[mu]m BiCMOS DMOS process, is demonstrated. In the second part, a high-efficiency wideband envelope tracking power amplifier for mobile LTE applications will be presented. The CMOS envelope amplifier with hybrid linear and switcher is designed in a 150 nm CMOS process. The envelope amplifier employs direct sensing of the linear stage current to reduce the propagation delay in the switcher. The strategy is demonstrated to improve the efficiency of the complete envelope tracking power amplifier system. The resulting performance of envelope tracking system employing a GaAs HBT-based RF PA with a 5 MHz LTE signal input demonstrated state-of-the-art efficiency while meet the linearity requirement.
Book Synopsis Concurrent Multi-band Envelope Tracking Power Amplifiers for Emerging Wireless Communications by : Hassan Sarbishaei
Download or read book Concurrent Multi-band Envelope Tracking Power Amplifiers for Emerging Wireless Communications written by Hassan Sarbishaei and published by . This book was released on 2014 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emerging wireless communication is shifting toward data-centric broadband services, resulting in employment of sophisticated and spectrum efficient modulation and access techniques. This yields communication signals with large peak-to-average power ratios (PAPR) and stringent linearity requirements. For example, future wireless communication standard, such as long term evolution advanced (LTE-A) require adoption of carrier aggregation techniques to improve their effective modulation bandwidth. The carrier aggregation technique for LTE-A incorporates multiple carriers over a wide frequency range to create a wider bandwidth of up to 100MHz. This will require future power amplifiers (PAs) and transmitters to efficiently amplify concurrent multi-band signals with large PAPR, while maintaining good linearity. Different back-off efficiency enhancement techniques are available, such as envelope tracking (ET) and Doherty. ET has gained a lot of attention recently as it can be applied to both base station and mobile transmitters. Unfortunately, few publications have investigated concurrent multi-band amplification using ET PAs, mainly due to the limited bandwidth of the envelope amplifier. In this thesis, a novel approach to enable concurrent amplification of multi-band signals using a single ET PA will be presented. This thesis begins by studying the sources of nonlinearities in single-band and dual-band PAs. Based on the analysis, a design methodology is proposed to reduce the sources of memory effects in single-band and dual-band PAs from the circuit design stage and improve their linearizability. Using the proposed design methodology, a 45W GaN PA was designed. The PA was linearized using easy to implement, memoryless digital pre-distortion (DPD) with 8 and 28 coefficients when driven with single-band and dual-band signals, respectively. This analysis and design methodology will enable the design of PAs with reduced memory effects, which can be linearized using simple, power efficient linearization techniques, such as lookup table or memoryless polynomial DPD. Note that the power dissipation of the linearization engine becomes crucial as we move toward smaller base station cells, such as femto- and pico-cells, where complicated DPD models cannot be implemented due to their significant power overhead. This analysis is also very important when implementing a multi-band ET PA system, where the sources of memory effects in the PA itself are minimized through the proposed design methodology. Next, the principle of concurrent dual-band ET operation using the low frequency component (LFC) of the envelope of the dual-band signal is presented. The proposed dual-band ET PA modulates the drain voltage of the PA using the LFC of the envelope of the dual-band signal. This will enable concurrent dual-band operation of the ET PA without posing extra bandwidth requirements on the envelope amplifier. A detailed efficiency and linearity analysis of the dual-band ET PA is also presented. Furthermore, a new dual-band DPD model with supply dependency is proposed in this thesis, capable of capturing and compensating for the sources of distortion in the dual-band ET PA. To the best of our knowledge, concurrent dual-band operation of ET PAs using the LFC of the envelope of the dual-band signal is presented for the first time in the literature. The proposed dual-band ET operation is validated using the measurement results of two GaN ET PA prototypes. Lastly, the principle of concurrent dual-band ET operation is extended to multi-band signals using the LFC of the envelope of the multi-band signal. The proposed multi-band ET operation is validated using the measurement results of a tri-band ET PA. To the best of our knowledge, this is the first reported tri-band ET PA in literature. The tri-band ET PA is linearized using a new tri-band DPD model with supply dependency.
Book Synopsis Dynamic Power Supply Transmitters by : Earl McCune
Download or read book Dynamic Power Supply Transmitters written by Earl McCune and published by Cambridge University Press. This book was released on 2015-05-21 with total page 495 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Power is dissipated (lost) when this current flows through any resistance, which includes the amplifier's transistor. This dissipated power is the product of the current in the load times the voltage difference between the supply voltage to the amplifier and the output signal voltage. When the voltage supplied to the amplifier is a constant value, and by far the most common design practice, the situation in Fig. 1-2a results. Power dissipation in the amplifier is maximum when the output signal voltage is 1/2 of the supply voltage. When the output signal voltage is higher, even though the current value is larger the voltage drop is less and the power dissipation is lower. Similarly, when the output signal voltage is small, even though the voltage drop is now large the current in the load is smaller and again the power dissipation is lower"--
Book Synopsis High-Efficiency Load Modulation Power Amplifiers for Wireless Communications by : Zhancang Wang
Download or read book High-Efficiency Load Modulation Power Amplifiers for Wireless Communications written by Zhancang Wang and published by Artech House. This book was released on 2017-06-30 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: This cutting-edge resource presents a complete and systematic overview of the practical design considerations of radio frequency (RF) high efficiency load modulation power amplifiers (PA) for modern wireless communications for 4G and beyond. It provides comprehensive insight into all aspects of load modulation PA design and optimization not only covering design approaches specifically for passive and active load modulation operation but also hybrid with dynamic supply modulation and digital signal processing algorithms required for performance enhancement. Passive load impedance tuner design, dynamic load modulation PA, active load modulation PA and Doherty PA design for efficiently enhancement are explained. Readers find practical guidance into load modulation PA design for bandwidth extension, including video bandwidth enhancement techniques, broadband dynamic load amplifiers, topology selection, design procedures, and network output. This book presents the evolution and integration of classical load modulation PA topologies in order to meet new challenges in the field.
Book Synopsis High Efficiency Broadband Envelope-Tracking Power Amplifiers by : Jonmei Johana Yan
Download or read book High Efficiency Broadband Envelope-Tracking Power Amplifiers written by Jonmei Johana Yan and published by . This book was released on 2013 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to meet the increasing demand for higher data rates while maximizing spectral efficiency, modern wireless communication systems transmit complex non-constant envelope modulation signals with high peak-to-average ratio (PAPR). As a result, conventional power amplifiers must be operated in back-off, leading to a significant efficiency reduction. Various power amplifier architectures (i.e. Doherty, outphasing, and envelope tracking) have been demonstrated to achieve high efficiency for these high PAPR signals. Unlike the other architectures, the envelope tracking power amplifier (ETPA) makes an excellent candidate for multi-band multi-frequency use, while maintaining high efficiency for high PAPR and under average power back-off, as it is fundamentally immune to changes in the frequency of the carrier; it depends only on the envelope of the RF signal. This dissertation focuses on the design of envelope tracking power amplifiers for enabling broadband wireless communication systems. First, a test-bench for evaluating broadband ETPAs is described. A calibration routine, acting as a pre-equalizer, is used to achieve a flat linear response over the entire instantaneous bandwidth of the system, resulting in less than 1% EVM for a 40 MHz LTE signal. Performances of envelope tracking power amplifiers on this test-bench at various frequencies from UHF to millimeter-wave are evaluated, and record efficiencies are demonstrated. Next, this dissertation describes how in under practical usage, the power transmitted fluctuates as a function of the load demands over time. The long-term efficiency of the ETPA is evaluated using Monte-Carlo simulations based on a projected time-varying power profile. Compared to a Doherty PA with the same peak efficiency, the ETPA can provide more than 1.4x reduction in overall energy consumed. The ETPA thus provides significant opportunities for system energy savings under realistic operation. Thirdly, to accommodate the wide range of carrier frequencies required for numerous emerging wireless systems, a multi-octave RFPA based on a compact GaN stacked IC with RC feedback is designed, fabricated, and evaluated. Multi-octave ET operation was demonstrated from 500 to 1750 MHz with >25% efficiency. Compared to its constant drain voltage counterpart, >2x improvement in RFPA efficiency is observed in ET. Lastly, while the ETPA provides advantages such as broad carrier bandwidths and high efficiency under back-off operation, one of the main challenges in ETPA design lies in accommodating wide modulation bandwidths. Adaptive de-troughing, a digital signal processing approach for extending the modulation bandwidth capability of an existing dynamic power supply, is described and evaluated. Measurements demonstrated the ability to extend ET operation to 20 MHz LTE signals. In addition, ~5-6% modulator efficiency enhancement was measured when comparing "standard" to "adaptive" de-troughing supply waveforms.
Book Synopsis Reconfigurable RF Power Amplifiers on Silicon for Wireless Handsets by : Laurent Leyssenne
Download or read book Reconfigurable RF Power Amplifiers on Silicon for Wireless Handsets written by Laurent Leyssenne and published by Springer Science & Business Media. This book was released on 2011-01-11 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reconfigurable RF Power Amplifiers on Silicon for Wireless Handsets is intended to designers and researchers who have to tackle the efficiency/linearity trade-off in modern RF transmitters so as to extend their battery lifetime. High data rate 3G/4G standards feature broad channel bandwidths, high dynamic range and critical envelope variations which generally forces the power amplifier (PA) to operate in a low efficiency “backed-off” regime. Classic efficiency enhancement techniques such as Envelope Elimination and Restoration reveal to be little compliant with handset-dedicated PA implementation due to their channel-bandwidth-limited behavior and their increased die area consumption and/or bill-of-material. The architectural advances that are proposed in this book circumvent these issues since they put the stress on low die-area /low power-consumption control circuitry. The advantages of silicon over III/V technologies are highlighted by several analogue signal processing techniques that can be implemented on-chip with a power amplifier. System-level and transistor-level simulations are combined to illustrate the principles of the proposed power adaptive solutions. Measurement on BICMOS demonstrators allows validating the functionality of dynamic linearity/efficiency management. In Reconfigurable RF Power Amplifiers on Silicon for Wireless Handsets, PA designers will find a review of technologies, architectures and theoretical formalisms (Volterra series...) that are traditionally related to PA design. Specific issues that one encounters in power amplifiers (such as thermal / memory effects, stability, VSWR sensitivity...) and the way of overcoming them are also extensively considered throughout this book.
Book Synopsis Envelope Amplifier Design for Wireless Base-station Power Amplifiers by : Chin Hsia
Download or read book Envelope Amplifier Design for Wireless Base-station Power Amplifiers written by Chin Hsia and published by . This book was released on 2010 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to deliver high data rates, modern wireless communication systems transmit complex modulated signals with high peak-to-average ratio, which demands wide bandwidth and stringent linearity performance for power amplifiers. To satisfy spectral mask regulations and achieve adequate error vector magnitude, power amplifiers typically operate at 6 to 10 dB back-off from the maximum output power, leading to low efficiency. To overcome the low efficiency problem, the envelope tracking power amplifier architecture has been proposed for this type of application due to its feature of high efficiency over a wide power range. The overall efficiency of an envelope tracking system relies not only on performance of the RF power amplifier but also on that of an envelope amplifier that provides a dynamically varying power supply voltage. This dissertation focuses on envelope amplifier design for efficiency enhancement of envelope tracking power amplifiers. First, the envelope tracking power amplifier architecture is analyzed, and the efficiency of a RF transistor in the envelope tracking technique is described. Then envelope amplifier behavior is investigated and a general purpose simulator is developed for analyzing and designing an envelope amplifier. Power loss and efficiency of the envelope amplifier is analyzed and compared with experimental results. The design of envelope amplifiers for high voltage (> 30 V) envelope tracking applications is described. A high voltage envelope amplifier is designed, implemented and verified. The overall envelope tracking system employing a GaN-HEMT RF transistor is demonstrated. Finally, a new architecture is developed for the efficiency enhancement of envelope amplifiers, using a digitally assisted controller design. Digital control is utilized to mitigate delay in the control loop inside the envelope amplifier, leading to lower overall power dissipation. A novel envelope amplifier architecture with dual-switcher stages based on the digitally-assisted control strategy is proposed, designed and implemented. The strategy is demonstrated to improve the efficiency of envelope amplifier as well as the system overall efficiency. The resulting performance of envelope tracking system employing a GaAs high voltage HBT with a single carrier W-CDMA input demonstrated state-of-the-art efficiency with good linearity performance.
Book Synopsis Design of the Envelope Tracking Hybrid Supply Modulator for Power Amplifier in LTE-20MHz Wireless Communication Applications by : 鄧厚威
Download or read book Design of the Envelope Tracking Hybrid Supply Modulator for Power Amplifier in LTE-20MHz Wireless Communication Applications written by 鄧厚威 and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis High Efficiency Linear Envelope Tracking and Envelope Elimination and Restoration Power Amplifier for WLAN OFDM Applications by : Feipeng Wang
Download or read book High Efficiency Linear Envelope Tracking and Envelope Elimination and Restoration Power Amplifier for WLAN OFDM Applications written by Feipeng Wang and published by . This book was released on 2006 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: High efficiency radio frequency (RF) power amplifiers (PAs) are critical in portable battery-operated wireless communication systems because they can dominate the power consumption. Linear power amplifier is required for envelope modulated signal. Traditionally, linear power amplifiers are implemented by "backing-off" the Class-A or Class-AB PA. However for a high peak-to-average (PAR) signal, the average efficiency is much lower than the peak efficiency, which is well down as the inherent trade-off between linearity and efficiency. This dissertation focuses on Envelope Elimination and Restoration (EER) and Envelope Tracking (ET) efficiency enhancement techniques to improve the PA average efficiency for high PAR signal. The EER and ET PA structures are investigated. Wideband ET and "hybrid" EER structures are proposed for WLAN 802.11g signal at 20MHz signal. Two major challenges of the wideband EER and ET PAs are investigated: 1) An adaptive time-alignment algorithm was proposed to calibrate the time-mismatch in wideband EER and ET systems; (2) A high efficiency wideband envelope amplifier is designed for wideband EER and wideband ET applications. A monolithic wideband high efficiency ET power amplifier is designed and implemented for WLAN 802.11g applications in IBM SiGe BiCMOS technology. Digital pre-distortion was implemented to reduce the EVM of the amplifier. The measured overall power-added efficiency of the amplifier is 28% at 20 dBm (100mW) output power.
Book Synopsis Bandwidth and Efficiency Enhancement in Radio Frequency Power Amplifiers for Wireless Transmitters by : Karun Rawat
Download or read book Bandwidth and Efficiency Enhancement in Radio Frequency Power Amplifiers for Wireless Transmitters written by Karun Rawat and published by Springer Nature. This book was released on 2020-03-05 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on broadband power amplifier design for wireless communication. Nonlinear model embedding is described as a powerful tool for designing broadband continuous Class-J and continuous class F power amplifiers. The authors also discuss various techniques for extending bandwidth of load modulation based power amplifiers, such as Doherty power amplifier and Chireix outphasing amplifiers. The book also covers recent trends on digital as well as analog techniques to enhance bandwidth and linearity in wireless transmitters. Presents latest trends in designing broadband power amplifiers; Covers latest techniques for using nonlinear model embedding in designing power amplifiers based on waveform engineering; Describes the latest techniques for extending bandwidth of load modulation based power amplifiers such as Doherty power amplifier and Chireix outphasing amplifiers; Includes coverage of hybrid analog/digital predistortion as wideband solution for wireless transmitters; Discusses recent trends on on-chip power amplifier design with GaN /GaAs MMICs for high frequency applications.
Book Synopsis Envelope Amplifier for Broadband Base-station Envelope Tracking Power Amplifier by : Qiuyao Zhu
Download or read book Envelope Amplifier for Broadband Base-station Envelope Tracking Power Amplifier written by Qiuyao Zhu and published by . This book was released on 2011 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: Envelope tracking (ET), which is a dynamic supply control technology to realize high efficiency power amplifiers, is a promising approach for base-station transmitters of the future. The envelope amplifier (EA) in ET systems provides a non-constant modulated power supply to the RF transistor. It is challenging to design so that it is both broadband and high efficiency, while meeting the stringent linearity requirements for high peak-to-average ratio signals in modern wireless communication systems. This thesis focuses on EA design and implementation for efficiency enhancement of ET systems with broadband envelope input signals. First, the ET system architecture is analyzed, and the efficiencies of RF transistors and envelope amplifiers are described. Secondly, the principles of the EA operation are investigated, and each circuit stage is carefully designed for broadband signals. Then, an EA model, including the RF transistor load, is developed in PSpice, and many simulations are described in order to better analyze and design the broadband EA for high efficiency. After the design, a broadband EA is implemented on a PCB board. The testing with constant resistive loads is carried out to verify the function and measure the efficiencies of 5 MHz WCDMA and 20 MHz LTE-A downlink envelope signals. Finally, tests on the whole ET system are performed, and the overall drain and power added efficiencies are tabulated. For this broadband envelope amplifier, the efficiency for a 5 MHz WCDMA input signal is above 75%, and for 20 MHz LTE-A, it works robustly with an efficiency of 62%.
Book Synopsis RF Power Amplifiers for Wireless Communications by : Steve C. Cripps
Download or read book RF Power Amplifiers for Wireless Communications written by Steve C. Cripps and published by Artech House Publishers. This book was released on 2006-01-01 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: This extensively revised edition offers a comprehensive, practical, up-to-date understanding of how to tackle a power amplifier design with confidence and quickly determine the cause of malfunctioning hardware.
Book Synopsis Design of Linear RF Outphasing Power Amplifiers by : Xuejun Zhang
Download or read book Design of Linear RF Outphasing Power Amplifiers written by Xuejun Zhang and published by Artech House. This book was released on 2003 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book devoted exclusively to the outphasing power amplifier, covering the most recent research results on important aspects in practical design and applications. A compilation of all the proposed outphasing approaches, this is an important resource for engineers designing base station and mobile handset amplifiers, engineering managers and program managers supervising power amplifier designs, and R&D personnel in industry. The work enables you to: design microwave power amplifiers with higher efficiency and improved linearity at a lower cost; understand linearity and performance tradeoffs in microwave power amplifiers; and understand the effect of new modulation techniques on microwave power amplifiers.
Book Synopsis Microwave Circuit Design Using Linear and Nonlinear Techniques by : George D. Vendelin
Download or read book Microwave Circuit Design Using Linear and Nonlinear Techniques written by George D. Vendelin and published by John Wiley & Sons. This book was released on 2021-04-27 with total page 1202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Four leaders in the field of microwave circuit design share their newest insights into the latest aspects of the technology The third edition of Microwave Circuit Design Using Linear and Nonlinear Techniques delivers an insightful and complete analysis of microwave circuit design, from their intrinsic and circuit properties to circuit design techniques for maximizing performance in communication and radar systems. This new edition retains what remains relevant from previous editions of this celebrated book and adds brand-new content on CMOS technology, GaN, SiC, frequency range, and feedback power amplifiers in the millimeter range region. The third edition contains over 200 pages of new material. The distinguished engineers, academics, and authors emphasize the commercial applications in telecommunications and cover all aspects of transistor technology. Software tools for design and microwave circuits are included as an accompaniment to the book. In addition to information about small and large-signal amplifier design and power amplifier design, readers will benefit from the book's treatment of a wide variety of topics, like: An in-depth discussion of the foundations of RF and microwave systems, including Maxwell's equations, applications of the technology, analog and digital requirements, and elementary definitions A treatment of lumped and distributed elements, including a discussion of the parasitic effects on lumped elements Descriptions of active devices, including diodes, microwave transistors, heterojunction bipolar transistors, and microwave FET Two-port networks, including S-Parameters from SPICE analysis and the derivation of transducer power gain Perfect for microwave integrated circuit designers, the third edition of Microwave Circuit Design Using Linear and Nonlinear Techniques also has a place on the bookshelves of electrical engineering researchers and graduate students. It's comprehensive take on all aspects of transistors by world-renowned experts in the field places this book at the vanguard of microwave circuit design research.
Book Synopsis Power Efficiency Enhancement and Linearization Techniques for Power Amplifiers in Wireless Communications by :
Download or read book Power Efficiency Enhancement and Linearization Techniques for Power Amplifiers in Wireless Communications written by and published by . This book was released on 2020 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wireless communication systems require Power Amplifiers (PAs) for signal transmissions. The trade-off between power efficiency and nonlinear distortion in PAs degrades the communication performance. Thus, power efficiency and nonlinearity are two main concerns of operating PAs in communication systems. Nonlinear behavioral models are typically used to quantify and mitigate the distortion effects of PAs on communication systems. This dissertation presents an estimation approach for modeling and linearizing the PA Amplitude-to-Amplitude (AM/AM) nonlinearity using the design specifications of PAs, such as gain, the third-order intercept point, and 1dB compression point. Furthermore, an enhanced approach for modeling solid-state power amplifiers is developed by modifying the Saleh empirical model. The Envelope Tracking (ET) technique for PAs has been a popular power efficiency enhancement in modern cellular systems. However, the time-varying effects of the supply voltage impacts the PA linearity. Therefore, an accurate behavioral model for PA with ET has become an important research effort to characterize the effect of dynamic supply voltage on both the amplitude and phase nonlinearities. Furthermore, the empirical models of ET PAs are widely used to improve PAs linearity by using Digital Predistortion (DPD). This dissertation develops an extended modeling approach to characterize the AM/AM and Amplitude-to-Phase (AM/PM) conversions as well as account for the impact of the time-varying supply voltage on the ET PAs. Memory effects, due to energy storage elements (e.g. capacitors and inductors) in ET PA circuits in addition to the temperature variation of integrated circuit, are modeled using digital filters (finite impulse-response filters) in series with the static AM/AM and static AM/PM nonlinearities. A least-squares approach is mathematically derived for estimating the model coefficients of ET PAs. The model identification of many coefficients requires high computational cost in Float Point Operations (FLOPS), such as multipliers and adders. In addition, the computational cost in FLOPs of a complex number is equivalent to (2-6) times the cost of real numbers. The estimation complexity of the ET PAs model in this work requires around half the number of FLOPS compared to the state-of-the-art behavioral models. This is because the modeling approach in this work consists of real coefficients and a lower number of model parameters. A DPD model is derived in this dissertation to compensate for both the AM/AM and AM/PM nonlinear distortions in ET PAs. A dual-input single-output function architecture is calculated for the DPD model to compensate for the nonlinearities in the AM/AM and AM/PM conversions contributed by the time-varying supply voltage in the ET system. Both the proposed AM/AM and AM/PM DPD models exhibit lower numbers of coefficients, which result in reduction of the identification complexity compared to the state-of-the-art DPD models. The proposed behavioral models of the ET PA and DPD are both evaluated in the time and frequency domains, as well as compared to the state-of-the-art models in terms of model accuracy and estimation complexity.
Book Synopsis Signal Processing Techniques for Power Efficient Wireless Communication Systems by : Fernando Gregorio
Download or read book Signal Processing Techniques for Power Efficient Wireless Communication Systems written by Fernando Gregorio and published by Springer Nature. This book was released on 2019-11-23 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a synthesis of the research carried out in the Laboratory of Signal Processing and Communications (LaPSyC), CONICET, Universidad Nacional del Sur, Argentina, since 2003. It presents models and techniques widely used by the signal processing community, focusing on low-complexity methodologies that are scalable to different applications. It also highlights measures of the performance and impact of each compensation technique. The book is divided into three parts: 1) basic models 2) compensation techniques and 3) applications in advanced technologies. The first part addresses basic architectures of transceivers, their component blocks and modulation techniques. It also describes the performance to be taken into account, regardless of the distortions that need to be compensated. In the second part, several schemes of compensation and/or reduction of imperfections are explored, including linearization of power amplifiers, compensation of the characteristics of analog-to- digital converters and CFO compensation for OFDM modulation. The third and last part demonstrates the use of some of these techniques in modern wireless-communication systems, such as full-duplex transmission, massive MIMO schemes and Internet of Things applications.
