Acknowledgements

This thesis is based on research work carried out at the Electronics Laboratory of the Department of Electrical Engineering and Infotech Oulu, University of Oulu, during the years 1994–2002.

I wish to express my gratitude to Professor Juha Kostamovaara, who has supervised this work for his tireless encouragement and guidance. I am also grateful to Dr. Tarmo Ruotsalainen and Dr. Kari Määttä for their help and support. I thank my colleagues at the Electronics Laboratory for the pleasant working atmosphere and for their assistance. My family deserve my warmest thanks for their support during these years.

I wish to thank Professors Günter Kompa and Hannu Tenhunen for examining this thesis, and Mr. Malcolm Hicks for revising the English of the manuscript.

The work was supported financially by the Graduate School in Electronics, Telecommunications and Automation, the Academy of Finland, the Technology Development Centre of Finland (TEKES) and the foundations Emil Aaltosen säätiö, Oulun yliopiston tukisäätiö, Seppo Säynäjäkankaan tiedesäätiö, Tauno Tönningin säätiö, Tekniikan edistämissäätiö and Walter Ahlströmin säätiö, all of which are gratefully acknowledged.

Oulu, March 2003                                                                                    Pasi Palojärvi