DOCTORAL DISSERTATION Medium Access Control Protocols for Energy and Delay Efficient Applications of Wireless Sensor Networks Dissertation zur Erlangung des akademischen Grades eines

ii iii Acknowledgment It is my pleasure to write down a few lines about the people who made my Ph.D. a nice, interesting, and rewarding experience. I found them always with me whenever I looked around. I would like to thank them for motivating and encouraging me during this venture. First and foremost, I am proudly grateful to my supervisor, Prof. Dr. Mesut Güne, whose thoughtful and logical guidance, insightful vision, continuing sup-port, and frank nature have leaded me to grow immensely over the couple of years. He not only motivated me on technical grounds and provided friendly and enlight-ening environment but also gave me full freedom to explore my research interests. How to start with research, how to formulate research problems, how to narrow down research interests, what is the technical writing and many more `hows ' and `whats ' I have learnt from him. His suggestions other than technical ones are also of higher value to my future life. In simple, this work would have never happened if it wasn't with him. I would like to express my special gratitude to Prof. Dr. Jochen Schiller for being cooperative and helpful throughout these years. Taking this opportunity, I would also like to thank Dr. Abd-Al-Basset Al-Mamou, Bastian Blywis, Qasim Mushtaq, Felix Juraschek, Hans Peter Heitzman, and all other colleagues for their constant support and help. I am deeply indebted to my wife and children for bearing with me during my research time and for being away from parents, relatives, and friends whilst sacrificing own education, language, culture, and much more. I have no words to explain incessant support from my mother, brothers, sisters, and friends during this time. This achievement is only possible with their understanding, patience, and encouragement. Thank you very much