پردازش سیگنال برای کاهش نقص‌های RF در ارتباطات بی‌سیم

A wireless communication system employs a radio frequency (RF) wave to transmit information bearing signals. In modern digital communication systems, sophisticated modulation techniques are developed to modulate information onto an RF carrier waveform, so as to transmit more information. This new book presents signal processing techniques for reducing impairments of analog and RF circuits in wireless communications systems. Engineers, researchers, and students will find full coverage of the topic, including vector modulators, power amplifiers, vector demodulators, group delay distortion in analog/RF filters, digital beamforming networks, and dual polarization systems. Several applications are discussed, including both single carrier and multi-carrier scenarios. Signal Processing for RF Circuit Impairment Mitigation Contents Preface 1 Introduction 1.1 A Basic Wireless Communication System 1.2 Spatial Diversity Transmissions 1.3 Dual-Polarization Transmissions 1.4 Impairment Mitigation by Signal Processing Reference 2 I/Q Impairment and Compensation Techniques 2.1 Introduction 2.2 Some Preliminaries 2.2.1 Direct-Conversion Quadrature Modulator 2.2.2 Direct-Conversion Quadrature Demodulator 2.3 Modulator I/Q Impairment Compensation 2.3.1 I/Q Impairment Modeling 2.3.2 Frequency-Independent Impairment Compensation 2.3.3 Frequency-Dependent Impairment Compensation 2.4 Demodulator I/Q Impairment Compensation 2.4.1 I/Q Impairment Modeling 2.4.2 Frequency-Independent Impairment Compensation 2.4.3 Frequency-Dependent Impairment Compensation 2.5 Conclusion References 3 Nonlinear PA Linearization 3.1 Introduction 3.1.1 PA Nonlinearity 3.1.2 Linearization Approaches 3.2 Linearization of Memoryless PA 3.2.1 Parametric Approaches 3.2.2 Performance of Parametric Approaches 3.2.3 Nonparametric Approaches 3.2.4 Performance of Nonparametric Approaches 3.3 Lineariation of PA with Memory Effect 3.3.1 Generic Predistortion Formulation 3.3.2 Volterra Series Model 3.3.3 Memory Polynomial (MP) Model 3.3.4 Generalized Rational Function Model 3.3.5 Performance Illustration 3.4 Joint Mitigation Techniques 3.4.1 Conventional Quadrature Transmitter 3.4.2 LINC Transmitter 3.5 Conclusion References 4 RF Circuit In-Band Distortion Compensation 4.1 Introduction 4.2 In-Band Distortion Modeling 4.2.1 Model of RF Circuit In-Band Distortion 4.2.2 Effects of In-Band Distortion 4.3 In-Band Distortion Compensation 4.3.1 Compensation by Equalization 4.3.2 Frequency-Domain Equalization Filter Design 4.3.3 Time-Domain Equalization Filter Design 4.3.4 FIR Implementation of Equalization Filter 4.4 Performance Study 4.4.1 Computer Simulation 4.4.2 Prototype Experimentation 4.5 Conclusion References 5 Array Calibration for Digital Beamforming Applications 5.1 Introduction 5.2 Principle of Digital Beamforming System 5.3 RF Impairment Modeling and Effects 5.3.1 RF Impairment Model 5.3.2 Effects of RF Impairment 5.4 Calibration Model 5.5 Type-Based Calibration Approach 5.5.1 Measure of Signal Distortion 5.5.2 Calibration Coefficient Estimation 5.5.3 Simulation Study 5.6 Kurtosis-Based Calibration Approach 5.6.1 Measure of Signal Distortion 5.6.2 Calibration Coefficient Estimation 5.6.3 Simulation Study 5.6.4 Comparative Discussion 5.7 Conclusion References 6 Cross-Polarization Interference Cancellationin Dual-Polarization Communication Systems 6.1 Introduction 6.2 Cross-Polarization Interference Models 6.3 Cross-Polarization Interference Cancellation Model 6.4 Type-Based Cancellation Approach 6.4.1 Measure of Signal Distortion 6.4.2 Estimation of Cancellation Parameters 6.4.3 Simulation Study 6.5 Kurtosis-Based Cancellation Approach 6.5.1 Measure of Signal Distortion 6.5.2 Estimation of Cancellation Parameters 6.5.3 Simulation Study 6.6 Conclusion References 7 Carrier Frequency Offset (CFO) and Phase Noise (PHN) Mitigation 7.1 Frequency Offset and PHN Modeling 7.2 Effects of Frequency Offset and PHN 7.3 Compensation Techniques 7.3.1 PHN Compensation 7.3.2 Frequency Offset Compensation 7.4 Joint I/Q Imbalance and Frequency Offset Compensation 7.4.1 Signal Models 7.4.2 Compensation Techniques 7.5 Conclusion References List of Symbols Index