Frequency selective Rician fast fading estimation for the downlink of TD-SCDMA system in the presence of a residual frequency offset

In this paper, a new scheme is proposed for estimating the frequency selective Rician fast fading channel for the downlink of TD-SCDMA system in the presence of a residual frequency offset (RFO). Via modifying the burst structure, the channel impulse response (CIR) with the RFO for each block of the modified burst structure is first modeled as a linear function of time, which is analysed and verified by theory and computer simulation, respectively. Then, a maximum-likelihood-based method is presented along with the modified burst structure to estimate these time-varying CIR coefficients with the RFO. Finally, the simulation results illustrate that the proposed method leads to small mean square error for fading estimation even at high speed of the mobile terminals and the RFO up to 200 km/h and 200 Hz, respectively.