Research On WMANOFDM Synchronization And System Simulation

Wireless metropolitan area network(WMAN) is another wideband wireless connection technology after the Wireless local area network(WMAN) came out. About WMAN, IEEE 802.16 Group published IEEE802.16 protocol and took OFDM as the typical physical layer technology.OFDM(Orthogonal Frequency Division Multiplexing) is a multi-carrier modulation technology which has been taken as the physical standard by many international criterions, and it is very suitable to be used in the wireless telecommunication field. The difficulty to implement OFDM is the high requirement of the synchronization precision. For the avoidance of the ICI and ISI, it is nessary to get accurate timing and frequency error estimation.The paper introduces the implementation of the OFDM technology in WMAN and takes a deep research on OFDM synchronization. According to IEEE802.16 protocol, the new frame synchronization algorithm and improved ML estimation algorithm fit for using on WMAN physical layer specification was proposed. The simulation shows, the new frame synchronization algorithm can increase the synchronization accuracy and has a low calculate complexity. Besides, it won't be affected by the frequency offset. The improved ML estimate algorithm can increase the performance of frequency offset estimation and has a better performance in the AWGN channel and multi-path channel.Based on the research of WMANOFDM synchronization, the implementation of IEEE802.16 software simulation platform is also introduced. First the system modeling has been proposed and the research about each model has been carried out. According to the physical layer specification of IEEE802.16 protocol, a full software simulation system has been built by LabVIEW. Simulation shows the system accords with IEEE802.16a protocol and can simulate different modulations as well as channel conditions by setting the parameters of the system. The common OFDM technology and the new methods proposed have been encapsulated to the software module to be used by the simulation system and the comparison of different technologies can be made. For the common use, the simulation platform provides uniform interfaces, works with different software modules and shows the functions of them in the form of data and graph, and supports the further researches of the WMANOFDM synchronization.