Spatial Error Concealment in Ad-hoc Audio Conferencing Systems

I would like to express profound gratitude to my advisor in Nokia ResearchCenter-Lausanne, Matti H¨am¨al¨ainen. Thank you for your continuous sup-port during the project and for teaching me how to deal with the technicaldifficulties in industry and thank you for always being there in the difficulties.I would like to thank my advisor in EPFL, Mihailo Kolundˇzija. Withoutyour guidance and persistent help this thesis would not have been finished.I would like to express the deepest appreciation to Prof. Martin Vetterli.It has been a great pleasure for me to know you and work with you duringmy several projects in your lab. Thank you for accepting me in LCAV andfor the enthusiasm and inspiration you have been always giving me.I am thankful to all my colleagues in Nokia Research Center-Lausannefor accepting me warmly and providing me the opportunity to work, to learnand to have fun. Special thanks to my friend, Mahdad Hosseini Kamal,who accompanied me on these project during this six months and left meunforgettable memories.I am grateful to Jussi Mutanen, Jussi Virolainen, and Kai Samposalo, fortheir kind meetings and helpful guidance during this work. Thank you forsharing you work with us and for the hours you spent on answering everysingle question we had.I would also like to thank Ville Myllyl¨a for providing the implementationof adaptive variable step-size method. I am also thankful to Henri Toukomaafor sharing the subjective test software and for computing the results.I am as ever, especially indebted to my family. Thank you for yourunconditional love, support and understanding throughout my studies. Iwould like to dedicate this thesis to you.ii