研究期間：10208~10307;OFDM technologies have focused a lot of research effort in academia and received substantial research and development attention in industry because they are expected to be the core technologies in the 4G standards of mobile communication in the near future. In this project, the primary purposes are to develop effective techniques of spectrum sensing, cell/sector search and channel estimation (CE) in practical mobile OFDM environments, then try to apply these methods to make carrier aggregation work. Meanwhile, the core and essential transceiving technologies and techniques, such as cell search, sector search, time-synchronization in OFDM, frequency offset estimation/compensation in OFDM, CE and equalization in OFDM will be deeply and thoroughly investigated. These techniques are studied in our preceding NSC research projects, and many preliminary outcomes were also learned to furthermore pursue much advanced research. Therefore, in this research, we not only deeply and thoroughly investigate current 4G techniques, but also consider the MIMO and distributed-chunk CE; meanwhile, in order to enhance the spectrum efficiency, the spectrum sensing and carrier aggregation techniques will be taken in to serious investigation. These important and essential techniques will be researched in theory and in practice in this research project.