Data-aided Doppler shift estimation for TD-SCDMA system over Rician

In this paper, a new Doppler shift estimator is proposed for Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) over Rician channels. Different from other existing methods, the proposed estimator is developed based on the training sequence, i.e., "midamble" and the statistical properties of demodulation signal. By the help of a training sequence, the received line-of-sight (LOS) signal is first demodulated. Afterwards, its second-order and fourth-order statistics are calculated. Then, by exploiting these statistical results, the Doppler shift estimator is obtained. The proposed estimator employs a smoothing function with corrective factor. By optimizing the corrective factor, an accuracy solution is acquired within the Doppler shift range of possibilities. Simulation results indicate that the proposed estimator is greatly reliable and effective to estimate Doppler shift up to 400 Hz.