Approved by: Efficient and QoS Guaranteed Data Transport in Heterogeneous Wireless Mobile Networks

To my family for their tremendous love, support, and belief in me. iii ACKNOWLEDGEMENTS First of all, I would like to express my sincere gratitude to my advisor, Dr. John A. Copeland, for his valuable guidance and support throughout this research. Besides providing excellent academic guidance, he has been incredibly encouraging, supportive and patient. It has been a great pleasure to have him as an advisor. I would like to express my appreciation to my dissertation committee members, Dr. Henry L. Owen, Dr. Gee-Kung Chang, Dr. Krishna V. Palem, and Dr. Jun Xu for reviewing this dissertation and providing constrictive comments. I am grateful to all the members of the Communications Systems Center (CSC) for their friendship. Conversations with the colleagues made me cheerful and technical discussions helped me to progress in this work. Special thanks goes to Cherita Corbett and Kulsoom Abdullah for their help, especially during the last stage of this work. Man