On The Algorithms And Implementation Of IEEE802.16d OFDM Synchronization And Channel Estimation

With the fast development of Intent and rapid growing of personal communication demands, two trends as "broad band" and "mobility" take on in the development of global communication techniques and systems, which accelerate the development of broadband wireless access technology. As a broadband wireless access scheme for WMAN (Wireless Metropolitan Area Networks), IEEE802.16d/e have received primary concern because of its outstanding system performance and wide market outlook, while the IEEE802.16d OFDM has become the first commercialized standard because of its easy development and low cost.The critical technologies of IEEE802.16d OFDM physical layer are researched in this dissertation, including the synchronization and channel estimation. Some synchronization algorithms are realized on the TS201, which is a DSP produced by AD company.At first, the development of WiMAX is reviewed, and the OFDM which is widely used in WiMAX system is also introduced.Chapter 2 as a key part of theory research of this paper mainly focuses on the synchronization of receiver. Firstly, a physical layer simulation link is set up based on the IEEE802.16d OFDM standard. Secondly, influences of synchronization errors are analyzed in theory based on a simple OFDM system model, and then the problems are pointed out in the stage of synchronization. At last, the timing synchronization, frequency synchronization and sampling frequency tracking algorithms are proposed according to the training sequence and pilot adopted by the IEEE802.16d OFDM system.Chapter 3 is mainly on the research of channel estimation methods, which are suitable for the IEEE802.16d OFDM systems. In this paper, the channel estimation gets from the long training sequence, the pilots are mainly used for tracking the residual frequency offset and sampling frequency offset, and the simulation results indicate that the algorithm works well in AWGN and SUI channel. And also a study on the decision directed channel estimation is carried out, and the simulation results indicate it can enhance the mobility of the IEEE802.16d OFDM system.Finally, timing synchronization and frequency synchronization algorithms are realized on TS201 and some optimization are also introduced.