Acknowledgments

I would like to express my deepest acknowledgement to my supervisor, Doctor Trinh Anh Vu for his support and guidance. Always when it was needed, he lent me his wealth of knowledge and experience. I am extremely impressed with his teaching, advising and generosity. His guidance and consistent encouragement help me a lot in completing this thesis.

I also acknowledge Mr. Vu Xuan Thang (Bsc) for his expertise and constructive suggestions that helped guide this research to complete.

I would also like to thank my colleagues from Department of Wireless Communications for creating friendly atmosphere that made long hours in our lab more enjoyable.

Finally, to my parents, I wish to extend my loving thanks for their encouragement. This thesis could not have been written without their daily encouragement.