Frequency domain iterative estimation of SNR and Doppler shift in mobile communications

Representing the reception condition directly, both Signal-to-noise ratio (SNR) and Doppler shift are important parameters in mobile channels, and therefore are widely used in system performance evaluations and adaptive applications. Accordingly, this paper investigates a frequency domain iterative estimator for SNR and Doppler shift in mobile communications, where the discrete cosine transform (DCT) is operated to the band-limited fading channel corrupted by the additive white gaussian noise (AWGN), and then the power spectrum density (PSD) of fading channels can be extracted from the calculated frequency domain samples. With the PSD estimation, we can iteratively estimate the noise variance and the spectrum width in an interlocked manner, where the former is related to SNR and the latter corresponds to the Doppler shift. Moreover, since DCT causes few spectrum leakages than the conventional fast fourier transform, the proposed method can converge within few iterations. We verify our algorithm by simulations and observe high accuracy in a wide range of velocities and SNRs.