BEN-GURION UNIVERSITY OF THE NEGEV FACULTY OF ENGINEERING SCIENCE DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING Sinusoidal Model Based Packet Loss Concealment for Wideband VoIP Applications THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE M.Sc DEGREE By: Dmitry Lihovetski January 2011 BEN-GURION UNIVERSITY OF THE NEGEV FACULTY OF ENGINEERING SCIENCE DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING Sinusoidal Model Based Packet Loss Concealment for Wideband VoIP Applications THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE M.Sc DEGREE By: Dmitry Lihovetski Supervised by: Prof. Ilan D. Shallom Prof. Dov Wulich Author: Date: ………………..……………….. ……………….. Supervisor: Date: ………………..……………….. ………………. Supervisor: Date: ………………..……………….. ………………. Chairman of Graduate Studies Committee: ………………..……………….. Date: ………………. January 2011 SINUSOIDAL MODEL BASED PACKET LOSS CONCEALMENT FOR WIDEBAND VOIP APPLICATIONS “Essentially, all models are wrong, but some are useful”1 - George E.P. Box (1919-present) Dmitry Lihovetski Israel, January 2011 1 Box, George E. P.; Norman R. Draper (1987). Empirical Model-Building and Response Surfaces, p. 424, Wiley. Sinusoidal Model Based Packet Loss Concealment for Wideband VoIP Applications Abstract Voice over Internet Protocol (VoIP) has become very popular in recent years. However, since internet delivery does not guarantee quality of service, data packets are often lost due to network congestions or significantly delayed. Packet loss is a fundamental problem in VoIP networks, unless concealed in some way, it produces an annoying disturbance in the resulting gaps. Therefore, there is considerable interest in developing Packet Loss Concealment (PLC) algorithms to compensate for missing voice packets. In this thesis, a new method for concealment of the missing packets for wideband VoIP applications is presented. The proposed approach is based on sinusoidal modeling of speech where it is reconstructed using sinusoidal generators controlled by amplitudes, frequencies and phases. The major idea is to exploit the continuity of sinusoidal representation and its simplified interpolation or extrapolation capabilities for isolated and consecutive packet loss. Sinusoidal modeling is used for producing synthetic speech analyzed from past packets and subsequent packets allowing packet extrapolation and interpolation under models parametric domain. Several model configurations are investigated, based on fully implemented concealment process tested with an objective voice quality method namely, Perceptual Evaluation of Speech Quality (PESQ). Using the large ITU-T coded speech database (Supplementary P.23) for statistical evaluation of results, it is revealed that the proposed algorithm outperform the standardized PLCs, ITU-T G.722 Appendixes III and IV, in average, under all tested packet loss rates and with increasing its superiority on higher rates. I Sinusoidal Model Based Packet Loss Concealment for Wideband VoIP Applications Keywords Voice over Internet Protocol, Packet Loss Concealment, Sinusoidal Model Based Packet Loss Concealment, Sinusoidal Modeling of Speech, Speech Normalization, Sinusoidal Model Extrapolation, Sinusoidal Model Interpolation, Sinusoidal Model Matching, Sender-Based Techniques, Receiver-Based Techniques, Voice Quality Evaluation, Perceptual Evaluation of Speech Quality, ITU-T P-Series Supplementary 23, NIST Net Emulation Tool. II Sinusoidal Model Based Packet Loss Concealment for Wideband VoIP Applications Acknowledgments I would like to express my sincere gratitude to Prof. Ilan Shallom and Prof. Dov Wulich for their support and encouragement throughout my graduate studies at Ben-Gurion University, especially for their devoted supervision and professional guidance in this research. It was their patient tutoring and invaluable advice that helped me to accomplish this thesis successfully. I am also thankful to all my fellow graduate students in the Signal Processing Laboratory for their companionship and fruitful discussions. My special thanks to all friends who took part in subjective tests during the development and final evaluation of the algorithm proposed in this research, and to Eitan Talianker and Vadim Mishalov, who accompanied me throughout my entire studies. Finally, I wish to thank my family and friends for their infinite care, love, support, patience and encouragement during my undergraduate and graduate studies. Dmitry Lihovetski Israel, January 2011 III Sinusoidal Model Based Packet Loss Concealment for Wideband VoIP Applications Contents 19TU U19T ABSTRACT I K19TU EYWORDSU19T II 19TU U19T ACKNOWLEDGMENTS III C19TU ONTENTSU19T IV 19TU U19T LIST OF ABBREVIATIONS AND ACRONYMS VII L19TU IST OF NOTATIONS AND SYMBOLSU19T XI 19TU U19T LIST OF FIGURES XIV L19TU IST OF TABLESU19T XVI 19T 19T 19TU U19T 1 INTRODUCTION 1 1.119TU U19T I19TU NTERNET TELEPHONYU19T ................................ ................................ ............................... 1 1.19TU 2 U19T V19TU OICE QUALITY EVOLUTION, WIDEBAND IMPROVEMENTS U19T ................................ ............. 2 1.319TU U19T R19TU ESEARCH GOALS AND RESULTSU19T ................................ ................................ ................ 4 1.419TU U19T D19TU OCUMENT OUTLINE U19T ................................ ................................ ................................ 4 219T 19T O19T VERVIEW OF VOICE OVER IP TECHNOLOGIES19T 6 2.119TU U19T V19TU OIP STANDARDS AND ORGANIZATIONSU19T ................................ ................................ ...... 6 2.219TU U19T V19TU OIP ARCHITECTUREU19T ................................ ................................ ................................ 7 2.319TU U19T M19TU EDIA TRANSPORT PROTOCOLSU19T ................................ ................................ .................. 8 2.419TU U19T M19TU EDIA ENCODING PROTOCOLSU19T ................................ ................................ ................... 8 2.519TU U19T M19TU EDIA PACKETIZINGU19T ................................ ................................ ................................ 9 2.5.119TU U19T R19TU EAL-TIME TRANSPORT PROTOCOL (RTP) U19T ................................ ..................... 10 2.619TU U19T V19TU OICE QUALITY IN INTERNET TELEPHONYU19T ................................ ................................ ..11 2.719TU U19T C19TU HARACTERIZATION OF PACKET LOSSU19T ................................ ................................ ........ 15 2.819TU U19T V19TU OICE QUALITY EVALUATIONU19T ................................ ................................ ................... 16 2.8.119TU U19T M19TU EAN OPINION SCORE (MOS)U19T ................................ ................................ ...... 19 2.8.219TU U19T E19TU -MODELU19T ................................ ................................ ................................ ... 20 2.8.319TU U19T P19TU ERCEPTUAL EVALUATION OF SPEECH QUALITY (PESQ)................................U19T ..22 2.8.419TU U19T N19TU ON-INTRUSIVE VOICE QUALITYU19T ................................ ................................ ..24 2.8.519TU U19T V19TU OICE QUALITY MEASURE SELECTIONU19T ................................ ........................... 25 2.919TU U19T P19TU ACKET LOSS RECOVERY TECHNIQUESU19T ................................ ................................ ....... 26 2.9.119TU U19T S19TU ENDER-BASED TECHNIQUESU19T ................................ ................................ ........ 27 IV Sinusoidal Model Based Packet Loss Concealment for Wideband VoIP Applications 19TU U19T 19TU U19T 2.9.2 RECEIVER-BASED TECHNIQUES ................................ ................................ ..... 27 2.9.319TU U19T C19TU ONCEALMENT ALGORITHMSU19T ................................ ................................ ........ 28 19T 19T 19T 19T 3 SINUSOIDAL MODELING OF SPEECH 35 3.119TU U19T S19TU INUSOIDAL MODELING EVOLUTION U19T ................................ ................................ .......... 35 19TU U19T 19TU U19T 3.1.1 RELATED RESEARCH ................................ ................................ .................... 36 3.219TU U19T S19TU PEECH PRODUCTION MODELU19T ................................ ................................ .................... 37 19TU U19T 19TU U19T 3.3 SPEECH ANALYSIS/SYNTHESIS BASED ON A SINUSOIDAL REPRESENTATION ..................... 38 3.3.119TU U19T S19TU INUSOIDAL SPEECH MODELU19T ................................ ................................ ........ 38 19TU U19T 19TU U19T 3.3.2 SINUSOIDAL MODEL PARAMETERS ESTIMATION ................................ .............. 40 3.3.319TU U19T S19TU INUSOIDAL MODEL SYNTHESISU19T ................................ ................................ .... 42 19T 19T 19T 19T 4 SINUSOIDAL MODEL BASED PACKET LOSS CONCEALMENT 45 4.119TU U19T G19TU ENERALIZED CONCEALMENT METHODU19T ................................ ................................ ...... 45 19TU U19T 19TU U19T 4.2 DESCRIPTION OF THE ALGORITHM ................................ ................................ .............. 46 4.2.119TU U19T B19TU UILDING BLOCKSU19T ................................ ................................ ...................... 47 19TU U19T 19TU U19T 4.2.2 CONTROL BLOCK ................................ ................................ ........................ 48 4.2.319TU U19T PLC19TU -IN BLOCKU19T ................................ ................................ ........................... 50 19TU U19T 19TU U19T 4.2.4 PLC-OUT BLOCK ...............................