Research Of Downlink Synchronization Algorithm And Design To Implementation Based On FPGA In WiMAX Baseband System

As the world’s first to use mobile broadband technology based on OFDMA, WiMAX(Worldwide Interoperability for Microwave Access) provides mobile broadband accesssolutions, for wireless metropolitan area network (Wireless Metropolitan Area Network,WMAN), it can be fixed and in mobile environment to provide high speed data, voice andvideo services. With the character of the mobile, broadband and IP, WiMAX has wideapplication prospect and be a great potential for development of the wireless accesstechnology.The paper study the synchronization algorithm which is one of the key factorsaffecting the performance of The mobile WiMAX system(IEEE802.16e protocol).First,it introduces the WiMAX technology, standards, development and current situation,.Then,it makes the corresponding introduction on important content of the WiMAX and theprinciple of OFDM. Finally，the paper propose and discuss the performance of WiMAXsynchronization algorithm according to the TU (Typical Urban) multipath channel andsector interference.At the same time, there are so much research on WiMAX algorithm theory but itshardware realization are discussed less. In this background, the article put forward acomplete solutions on the WiMAX synchronization algorithm and hardwareimplementation. Based on the FPGA architecture, the inter-related module, correlationmodule, frequency offset estimation module and so on is designed. With a flexiblestructure, more versatility and higher efficiency of the algorithm, and shorter developmentcycle, the system is easy to maintain and extend, which is suitable for real time signalprocessing.1) On the WiMAX physical layer OFDMA which relates to the carrier, sub channel,frame structure, subcarrier allocation and other important concepts of interpretation and thebasic principle of OFDMA system was described and analyzed, giving the downlinkbaseband system realization plan, It has formed a complete theoretical system of OFDMAphysical layer.2) For the TU multipath channel and sector interference, the WiMAX system OFDMAsynchronization algorithms was put up on the condition that concerning the complexity andthe occupation resources,reasonable structure, excellent performance.3) Based on QuartusII8.0which is the professional development platform of FPGAand Verilog HDL hardware description language, the synchronization frame detection, coarse symbol synchronization, fine symbol synchronization, fractional frequency offsetestimation, integer frequency offset estimation for FPGA are designed.4) Based on the Matlab platform, WiMAX model of communication system wasbuilded and authenticated algorithm performance; At the same time, the testbanch isprepared for FPGA module simulation and verification on Modelsim which is theindustry’s most popular hardware platform simulation tool.