On velocity estimation and correlation properties of narrow-band mobile communication channels

Estimation of the maximum Doppler spread or, equivalently, the vehicle velo city, is useful in improving handoff algorithms and necessary for the optim al tuning of parameters for systems that adapt to changing channel conditio ns. We provide a novel velocity estimator based on the spectral moments of the in-phase and the quadrature phase components or the envelope of the rec eived signal. We characterize the joint effects of the Ricean K factor, the directivity and the angle of nonisotropic scattering, and the effects of a dditive white noise on our estimator and other covariance-based velocity es timators analytically. We also prove the mean-square consistency of the cov ariance-based velocity estimators under some assumptions on the angle of ar rival distribution. Simulations illustrate our approach and compare with ex isting techniques.