My foremost and earnest appreciation goes to my supervisor, Associate Professor Wen-De Zhong. I am truly grateful for his professional guidance, invaluable assistance and encouragement throughout my graduate studies. I want to express my sincere thanks to my co-supervisor, Dr. Yang Jing Wen, of Institute for Infocomm Research for his countless hours of brainstorming discussion and good instruction. I am also deeply indebted to Professor Chao Lu who was my supervisor and led me to this exciting research area. I have benefited tremendously from his guidance. Throughout my thesis-writing period, the useful advice, good teaching, and well understanding from Prof. Zhong and Dr. Wen benefit me a lot. Without the endless supports of my supervisors, this work would not have come to fruition.