Abstract
In this thesis, we present two carrier frequency offset estimation algorithms applied to OFDM system. OFDM is popular transmitting technology for high data rate wireless communication systems. One of the major drawbacks is its high sensitivity to carrier frequency offset (CFO) due to the Doppler frequency and oscillator instability. The existence of a CFO brings about reduction of system performance due to the occurrence of inter-carrier interference (ICI). Geneally, the CFO estimation algorithms can be classified into three categories, which are pilot tone aided (PTA), cyclic prefix based (CPB), and training symbols based (TSB). Moreover, CFO can be divided into: integral and fractional part. In this thesis, we focus on the later. However, above estimation methods have some drawbacks: reduction of transmitted data rate or sensitivity of timing error. Here we propose two midified methods for estimating CFO based on PTA and CPB method, and desire to improve the principal drawbacks of original method. The key opinion of our proposed algorithms is exploitation of the data-carriers to provide more accurate frequency synchronization and provide better performance. Specifically, the effects of estimator are discussed and compared by simulation result in AWGN and UWB channel