RF Imperfections in High-rate Wireless Systems: Impact and Digital Compensation

（有书签和快捷方式）

RF Imperfections in High-rate Wireless Systems

Foreword xi

Preface xiii

1. INTRODUCTION 1

1.1 Wireless communications 1

1.2 OFDM 3

1.3 MIMO 4

1.4 RF transceiver impairments 6

1.5 Outline of the book 9

2. MULTIPLE-ANTENNA OFDM SYSTEMS 11

2.1 Introduction 11

2.2 Channel modelling 11

2.2.1 Multipath propagation 12

2.2.2 Stochastic channel model 16

2.3 System modelling 18

2.3.1 MIMO 19

2.3.2 OFDM 22

2.3.3 MIMO OFDM 26

2.4 Conclusions 29

3. DESIGN AND IMPLEMENTATION OF A MIMO OFDM

SYSTEM 31

3.1 Introduction 31

3.2 Transmission format and preamble design 32

3.2.1 IEEE 802.11a 32

3.2.2 MIMO OFDM 34

3.3 Frequency synchronisation 39

3.3.1 Influence of CFO 40

3.3.2 Algorithm description 42

3.3.3 Performance analysis 44

3.3.4 Numerical results 47

3.3.5 Summary 51

3.4 Channel estimation 52

3.4.1 Algorithm and performance analysis 52

3.4.2 Numerical results 58

3.4.3 Summary 62

3.5 Timing synchronisation 62

3.5.1 System description 63

3.5.2 Algorithm description 66

3.5.3 Numerical results 68

3.5.4 Summary and discussion 72

3.6 Multiple-antenna OFDM system implementation 73

3.6.1 Test system description 73

3.6.2 Baseband design 74

3.6.3 Measurement results 76

3.6.4 Comparison with simulation results 79

3.7 Conclusions 81

4. PHASE NOISE 83

4.1 Introduction 83

4.2 System and phase noise modelling 84

4.2.1 Oscillator modelling 85

4.2.2 Influence on signal model 88

4.3 Impact and distribution of the ICI term 91

4.3.1 System model 91

4.3.2 Bit-error probabilities 94

4.3.3 Properties of the ICI term 95

4.3.4 Simulation results 104

4.3.5 Summary 107

4.4 ICI-caused error term in MIMO OFDM 108

4.4.1 Transmitter phase noise 109

4.4.2 Receiver phase noise 110

4.4.3 Phase noise process 112

4.4.4 Numerical results 113

4.4.5 Summary and discussion 116

4.5 Compensation of the CPE 117

4.5.1 Maximum-likelihood estimator 117

4.5.2 MLE optimisation algorithm 119

4.5.3 Sub-optimal estimator 121

4.5.4 Cram´er-Rao lower bound 122

4.5.5 Numerical results 124

4.5.6 Summary 130

4.6 Compensation of the ICI 130

4.6.1 Suppression algorithm 131

4.6.2 Numerical results 134

4.6.3 Summary 136

4.7 Conclusions 137

5. IQ IMBALANCE 139

5.1 Introduction 139

5.2 System and IQ imbalance modelling 140

5.2.1 TX/RX front-end architecture 141

5.2.2 IQ mismatch 143

5.2.3 Influence on MIMO signal model 145

5.2.4 RX filter imbalance 148

5.3 Impact of IQ imbalance on system performance 150

5.3.1 Error in symbol detection 150

5.3.2 Probability of erroneous detection

for M-QAM 152

5.3.3 Numerical results 159

5.3.4 Summary and discussion 163

5.4 Preamble based estimation and mitigation 163

5.4.1 Preamble design 164

5.4.2 TX IQ imbalance estimation 166

5.4.3 RX IQ imbalance estimation 167

5.4.4 TX and RX IQ imbalance estimation 168

5.4.5 Iterative TX and RX IQ imbalance estimation 170

5.4.6 Numerical results 172

5.4.7 Summary 177

5.5 Decision-directed mitigation 178

5.5.1 Adaptive filter based algorithm 178

5.5.2 Numerical results 180

5.6 Conclusions 182

6. NONLINEARITIES 185

6.1 Introduction 185

6.2 System and nonlinearities modelling 187

6.2.1 Nonlinearity modelling 187

6.2.2 Influence on signal model 192

6.3 Impact of nonlinearities on system performance 195

6.3.1 TX nonlinearities 196

6.3.2 RX nonlinearities 201

6.3.3 Numerical results 203

6.3.4 Summary and discussion 207

6.4 PAPR reduction by spatial shifting 208

6.4.1 Signal modelling 209

6.4.2 Spatial shifting 210

6.4.3 Combining SS and PS 211

6.4.4 Subcarrier grouping schemes 213

6.4.5 Side information/Transparency 213

6.4.6 Numerical results 215

6.4.7 Summary and discussion 217

6.5 RX-based correction of nonlinearities 219

6.5.1 Baseband amplitude clipping 220

6.5.2 Estimation of linear and nonlinear channel 221

6.5.3 Postdistortion 230

6.5.4 Iterative distortion removal 231

6.5.5 Simulation results 233

6.5.6 Summary 242

6.6 Conclusions 242

7. A GENERALISED ERROR MODEL 245

7.1 Introduction 245

7.2 Error model 246

7.2.1 TX and RX impairment model 247

7.2.2 Mapping of RF impairments 248

7.2.3 Nonstationarity of the impairments 250

7.2.4 Transmission structure 252

7.3 Performance evaluation 252

7.3.1 Preamble phase 253

7.3.2 Data phase 253

7.3.3 Probability of error 254

7.4 Numerical results 257

7.5 Conclusions 261

8. DISCUSSION AND CONCLUSIONS 263

8.1 Summary and conclusions 263

8.1.1 Synchronisation for MIMO OFDM systems 264

8.1.2 Multiple-antenna OFDM proof of concept 265

8.1.3 Behavioural RF impairment modelling 265

8.1.4 Performance impact of front-end imperfections 266

8.1.5 Mitigation approaches for RF impairments 267

8.1.6 A generalised error model 269

8.2 Scope of future research 270

8.2.1 Influence of RF impairments 270

8.2.2 Mitigation approaches 271

8.2.3 Towards mm-wave systems 272

Glossary 275

Appendices 281

A MSE in CFO estimation 281

B MSE in channel estimation 283

B.1 MSE in linear channel interpolation 283

B.2 MSE in linear channel extrapolation 284

C Measurement setup 287

C.1 Baseband 287

C.2 IF stages 289

C.3 Antennas 290

D Proof of Theorem 4.1 291

E Orthonormal polynomial basis 299

References 301

Index 315