A Doppler Offset Estimator By Using The Signal'S Cyclostationarity In Cdma System

In wireless communication, There may be large frequency-offset between the transmitter and receiver due to Doppler effects. So it's very complex to synchronize the mobile unit with the base station, and the receiver's performance is degraded rapidly. We propose a Doppler offset estimator by using the CDMA signal's cyclostationarity. The CDMA signal's cyclic frequency is drifted with the Doppler offset. Exploiting the CDMA signal's cyclostationarity and taking account of the affection of the finite sample data, we estimate the Doppler offset by calculating the signal's cyclic frequency. The estimator needs no training sequences, so it won't lower the data rate; the adding stationary noise can't affect the estimator. The simulating results show the estimator can estimate the Doppler offset fast and correctly in the fading environments.