ACKNOWLEDGEMENT

I would like to express my sincere gratitude to my thesis advisor, Dr. R.M.A.P. Rajatheva, for his guidance and unreserved help during the study period. My special thanks should go to the examination committee members Dr. Poompat Saengudom-lert, Dr. Teerapat Sanguankotchakorn for their constructive opinions and invaluable suggestions. My grateful thanks also go to the rest of the faculty members, all of the staff members in the telecommunications program for their constant support during my study period at AIT. Also I’m grateful to the assistant Professor Hlaing Minn, Uni-versity of Texas Dallas for extending his generous cooperation with my research study. His cooperation was much helpful in realizing the modern research trend in wireless communications. For financial support, I thank the Royal Thai Government. Without this scholar-ship, this thesis as well as the study at AIT would not have been possible. Moreover, I would like to convey my heartfelt appreciation to the PhD student, Mr. Prathapasinghe Dharmawansa for his precious instructions and guidance throughou