SNR-independent maximum Doppler frequency estimators with bandwidth adjustment technique

Information of the maximum Doppler frequency enable to optimize many channel-adaptive techniques and radio resource management methods for mobile radio communication systems. In this paper, we propose four maximum Doppler frequency estimators which are based on the level crossing rate (LCR), the zero crossing rate (ZCR), the covariance function (COV) and the autocorrelation function (ACF). To eliminate the influence of additive noise, we analyze the conditions for the estimators independent of the signal-to-noise ratio (SNR) and implement the conditions with a downsampling process in the time domain. The proposed methods achieve good SNR-independent performance in the Rayleigh fading channels