The Research Of OFDMA Timing Synchronization, Base On WiMax Standard:IEEE 802.16e

OFDM and it's relatived technology OFDMA have obvious advantage in the high using rate of frequency, can resist the multi-path effect ,decline in frequency difference, resist limited band intruder.It is a major technology which already been applied in the frequency band of 11GHz.It also used as a PHY layer technology in many wireless system,such as WLAN,DAB,DVB and B3G.The highly effective frequency using character has been more and more interested, the OFDMA system is sensitive of timing and frequency excursion, It will cause the jam of overload frequency. So it is important to have estimation and compensation to OFDMA system. The synchronization is a major research area in OFDMA system.The synchronization in WiMax IEEE802.16 standard include OFDM synchronization and OFDMA synchronization,It already has many research of OFDM system,but for OFDMA,it has more space to improve.The major work in this article:1. To OFDMA upload channel, we offer a solution of draft synchronization and detail synchronization.The draft one is responsible for detecting the OFDM signal occure and exact estimation for individual in detail period.2. The draft method of OFDMA synchronization. We offer an improved method which solve the question of current method of OFDM synchronization:T.M.Schildl Method:due to a flat in the wave peak,it will lead detection miss of the frame beginning. Base on the emulator,the new method has an obvious improvement. 3. The detail method of OFDMA synchronization. We offer a new method to solve current method question:a.The supposed states is too idealization and b The sub channel in IEEE802.16 standard is not continuous. We also have a emlulator for this method,The result show that the definition and veracity of the system synchronization are improved.