Study On Synchronization For Ofdm System Based On Ieee 802.11a

With the rapid increase of Internet, Orthogonal Frequency Division Multiplexing(OFDM) has invoked a popular research interest in recent years, as the important technology of broadband high-data-rate wireless communications. And the WLAN is generally considered as the 'last mile' in the connection of computers and wired networks. From the authorization of the first WLAN standards, Broadband Wireless Access(BWA) technology started to develop swiftly and violently. Latterly, the coming of IEEE802.11b and IEEE802.11a standards, the WLAN technology has been developed fast. And the Orthogonal Frequency Division Multiplexing(OFDM) is given more and more attention in wireless area, because OFDM lessens the severe effects of frequency selective fading and improves the spectrum efficiency, and this technology has been indicated to become a key technology in the fourth mobile communication.In this paper, we emphasis on investigating the key technology of OFDM, that is synchronization problems, which generally include frame synchronization, timing synchronization and carrier synchronization, at last we will simulate the whole system. Synchronization of based on IEEE802.11a OFDM system is mostly discussed. We also point out the strategy of using the preamble to fast and accurate acquire signal in the limited time and using pilot from the OFDM symbol to track synchronization the error signal after acquisition is suitable for OFDM receiver. It is clear that an integrated system synchronization has been advanced and a method of low-complexity frame detection and co-relation timing has been designed. Whereas OFDM system is sensible to frequency offset, we have minimized the influence of system bit error rate to the degree of the ideal synchronization in the channels of AWGN and Multiple-path by the two frequency offset and compensation. And the arithmetic and structure of synchronization tracking and tracking loop is analyzed and the best loop parameters are confirmed by simulation.Finally we will simulate the whole synchronization in a IEEE802.11a PYH, and gives analysis about simulations and some conclusions.