Velocity estimation-based channel estimator for WCDMA forward link receiver

In this paper, we propose a new architecture of channel estimator that can compensate for the signal distortion due to the variable mobile station velocity in WCDMA forward link. The proposed channel estimator consists of IIR filter for channel estimation and velocity estimator for selection of a IIR filter coefficients matched to the mobile station velocity. The combination of IIR filter and velocity estimator can overcome the divergence problem of IIR filer due to the mobile station velocity. The velocity estimator estimates the speed of mobile station velocity by observing power-spectrum of the received signal and exhibit stable operation in low SNR environment. To improve the resolution of velocity estimation without additional complexity, an interpolator is adapted in the velocity estimator. The proposed channel estimation algorithm cannot only be used for WCDMA forward link but also is applicable for cdma-2000 system without major modifications. Also, the velocity estimator can be applied in the channel quality measurement for the selection of MCS (modulation and coding scheme) level in HSDPA transmission.