Advances in Digital Speech Transmission

List of Contributors xxi

Preface xxvii

1 Introduction 1
Rainer Martin, Ulrich Heute, Christiane Antweiler

I Speech Quality Assessment 7

2 Speech-Transmission Quality: Aspects and Assessment for Wideband vs. Narrowband Signals 9
Ulrich Heute

2.1 Introduction 9

2.2 Speech Signals . 10

2.3 Telephone-Band Speech Signals 11

2.4 Wideband Speech Signals 14

2.5 Speech-Quality Assessment 25

2.6 Wideband Speech-Quality Assessment 30

2.7 Concluding Remarks 43

Bibliography 44

3 Parametric Quality Assessment of Narrowband Speech in Mobile Communication Systems 51
Marc Werner

3.1 Introduction 51

3.2 Simulations of GSM and UMTS Speech Transmissions 58

3.3 Speech Quality Measures based on Transmission Parameters 65

3.4 Discussion and Conclusions 73

Bibliography 73

II Adaptive Algorithms in Acoustic Signal Processing 77

4 Kalman Filtering in Acoustic Echo Control: A Smooth Ride on a Rocky Road 79
Gerald Enzner

4.1 Introduction 79

4.2 A Comprehensive Theory of Acoustic Echo Control 85

4.3 The Kalman Filter for Conditional Mean and Covariance Estimation 90

4.4 AEC Performance of the Frequency-Domain Adaptive Kalman Filter 100

4.5 Discussion and Conclusions 102

Bibliography 103

5 Noise Reduction - Statistical Analysis and Control of Musical Noise 107
Colin Breithaupt, Rainer Martin

5.1 Introduction 107

5.2 Speech Enhancement in the DFT Domain 109

5.3 Measurement and Assessment of Unnatural Fluctuations 115

5.4 Avoidance of Processing Artifacts 120

5.5 Control of Spectral Fluctuations in the Cepstral Domain 123

5.6 Discussion and Conclusions 128

5.7 Acknowledgements 129

5.8 Appendix 129

Bibliography 131

6 Acoustic Source Localization with Microphone Arrays 135
Nilesh Madhu, Rainer Martin

6.1 Introduction 135

6.2 SignalModel 136

6.3 Localization Approach Taxonomy 141

6.4 Indirect Localization Approaches 141

6.5 Direct Localization Approaches 148

6.6 Evaluation of Localization Algorithms 156

6.7 Conclusions 166

Bibliography 166

7 Multi-Channel System Identification with Perfect Sequences – Theory and Applications – 171
Christiane Antweiler

7.1 Introduction 171

7.2 System Identification with Perfect Sequences 174

7.3 Multi-Channel System Identification 185

7.4 Applications 191

7.5 Discussion and Conclusions 195

Bibliography 195

III Speech Coding for Heterogeneous Networks 199

8 Embedded Speech Coding: From G.711 to G.729.1 201
Bernd Geiser, Stéphane Ragot, Hervé Taddei

8.1 Introduction 201

8.2 Theory and Tools of Embedded Speech Coding 203

8.3 Embedded Speech Coding Methods 212

8.4 Standardized Embedded Speech Coders 219

8.5 Network Aspects of Embedded Speech Coding 232

8.6 Conclusions and Perspectives 237

Bibliography 238

9 Backwards Compatible Wideband Telephony 249
Peter Jax

9.1 Introduction 249

9.2 From Narrowband Telephony to Wideband Telephony 250

9.3 Stand-Alone Bandwidth Extension 254

9.4 Embedded Wideband Coding Using Bandwidth Extension Techniques 257

9.5 Combination of Bandwidth Extension with Watermarking 262

9.6 Advanced Transmission of Highband Parameters 267

9.7 Conclusions 274

Bibliography 274

IV Joint Source-Channel Coding 279

10 Parameter Models and Estimators in Soft Decision Source Decoding 281
Tim Fingscheidt

10.1 Introduction 281

10.2 Overview to Soft Decision Source Decoding 283

10.3 The Markovian Parameter Model 287

10.4 Basic Extrapolative Estimators 290

10.5 Joint Extrapolative Estimation of Two Different Parameters 298

10.6 Extrapolative Estimation with Repeated Parameter Transmission 301

10.7 Interpolative Estimation of a Parameter 304

10.8 Discussion and Conclusions 307

Bibliography 307

11 Optimal MMSE Estimation for Vector Sources with Spatially and Temporally Correlated Elements 311
Stefan Heinen, Marc Adrat

11.1 Introduction 311

11.2 Source Model 312

11.3 Transmission Channel 316

11.4 Optimal MMSE Parameter Estimator 316

11.5 Near-Optimal MMSE Parameter Estimator 320

11.6 Illustrative Comparison 323

11.7 Simulation Results 325

11.8 Conclusions 327

Bibliography 327

12 Source Optimized Channel Codes & Source Controlled Channel Decoding 329
Stefan Heinen, Thomas Hindelang

12.1 Introduction 329

12.2 The Transmission System Used as Reference 330

12.3 Source Optimized Channel Coding (SOCC) 332

12.4 Source Controlled Channel Decoding (SCCD) 341

12.5 Comparison of SOCC versus SCCD 357

12.6 Conclusions 362

Bibliography 363

13 Iterative Source-Channel Decoding & Turbo DeCodulation 365
Marc Adrat, Thorsten Clevorn, Laurent Schmalen

13.1 Introduction 365

13.2 The Key of the Turbo Principle: Extrinsic Information 366

13.3 Iterative Source-Channel Decoding (ISCD) 379

13.4 Turbo DeCodulation (TDeC) 387

13.5 Conclusions 394

Bibliography 395

V Speech Processing in Hearing Instruments 399

14 Binaural Signal Processing in Hearing Aids 401
Volkmar Hamacher, Ulrich Kornagel, Thomas Lotter, Henning Puder

14.1 Introduction 401

14.2 Wireless System for Hearing Aids 405

14.3 Binaural Classification Systems 410

14.4 Binaural Beamformer 415

14.5 Blind Source Separation (BSS): An Application for a Binaural Directional Microphone Array in Hearing Aids 422

14.6 Conclusions 427

Bibliography 428

15 Auditory-profile-based Physical Evaluation of Multi-microphone Noise Reduction Techniques in Hearing Instruments 431
Koen Eneman, Arne Leijon, Simon Doclo, Ann Spriet, Marc Moonen, Jan Wouters

15.1 Introduction 431

15.2 Multi-microphone Noise Reduction in Hearing Instruments 434

15.3 Auditory-profile-based Physical Evaluation 441

15.4 Test Conditions 449

15.5 Simulation Results 450

15.6 Discussion 452

15.7 Conclusions 455

Bibliography 456

VI Speech Processing for Human–Machine Interfaces 459

16 Automatic Speech Recognition in Adverse Acoustic Conditions 461
Hans-Günter Hirsch

16.1 Introduction 461

16.2 Structure of Speech Recognition Systems 462

16.3 Acoustic Scenarios during Speech Input 468

16.4 Improving the Recognition Performance in Adverse Conditions 476

16.5 Conclusions 493

Bibliography 494

17 Speaker Classification for Next-Generation Voice-Dialog Systems 497
Felix Burkhardt, Florian Metze, Joachim Stegmann

17.1 Introduction 497

17.2 Speaker Classification 498

17.3 Detection of Age and Gender 505

17.4 Detection of Anger 510

17.5 Applications in IVR Systems 517

17.6 Discussion and Conclusion 523

Bibliography 525

Index 529

Permissions List 541