Sensitivity of channel estimation using B-splines to mismatched Doppler frequency

In this paper, we investigate the pilot assisted maximum likelihood (ML) and minimum mean square error (MMSE) channel estimators using B-splines in time-variant Rayleigh fading channels following Jakes´ model. The analytical mean square error (MSE), including noise-free modeling error and statistical estimation error, of the channel estimators is derived. We also derive the overall MSE of the MMSE channel estimator with mismatched estimation of the Doppler frequency. The results show that the MMSE estimator using B-splines has little sensitivity to overestimation of the Doppler frequency. However, when the Doppler frequency is underestimated, even slightly, its performance degrades significantly and becomes much worse than that of the ML channel estimator.