Research On Time Domain Synchronization Technique For OFDM

Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) have been great concerned in the future broad-band wireless communication system. Timing synchronization and frequency synchronization are the key effects which influence the performance of OFDM system. This paper introduces timing and frequency synchronization algorithms in SISO/MIMO-OFDM systems thoroughly and comprehensively.As for OFDM system without assistant data, the typical synchronization algorithm ML estimation and the improved algorithms are discussed, an improved algorithm based on the delay-spread estimation is presented, the new algorithm can estimate anterior M-1 number of OFDM symbols more exactly. As for OFDM system with assistant symbols, base on protocol of IEEE802.11a, the frame synchronization and frequency synchronization are simulated, a new algorithm is imposed, using the eight short training symbols and two long training symbols to estimate frequency offset, the result of simulation indicates that the new algorithm has a higher performance of frequency synchronization. At last, two classical MIMO-OFDM algorithms are introduced,and an algorithm of synchronization about MIMO-OFDM base on the leading characters of IEEE802.11a is simulated, and the result of some simulations is shown.